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Sample records for inhibits root gravitropism

  1. Inhibition of phospholipase C disrupts cytoskeletal organization and gravitropic growth in Arabidopsis roots.

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    Andreeva, Zornitza; Barton, Deborah; Armour, William J; Li, Min Y; Liao, Li-Fen; McKellar, Heather L; Pethybridge, Kylie A; Marc, Jan

    2010-10-01

    The phospholipase protein superfamily plays an important role in hormonal signalling and cellular responses to environmental stimuli. There is also growing evidence for interactions between phospholipases and the cytoskeleton. In this report we used a pharmacological approach to investigate whether inhibiting a member of the phospholipase superfamily, phospholipase C (PLC), affects microtubules and actin microfilaments as well as root growth and morphology of Arabidopsis thaliana seedlings. Inhibiting PLC activity using the aminosteroid U73122 significantly inhibited root elongation and disrupted root morphology in a concentration-dependent manner, with the response being saturated at 5 μM, whereas the inactive analogue U73343 was ineffective. The primary root appeared to lose growth directionality accompanied by root waving and formation of curls. Immunolabelling of roots exposed to increasingly higher U73122 concentrations revealed that the normal transverse arrays of cortical microtubules in the elongation zone became progressively more disorganized or depolymerized, with the disorganization appearing within 1 h of incubation. Likewise, actin microfilament arrays also were disrupted. Inhibiting PLC using an alternative inhibitor, neomycin, caused similar disruptions to both cytoskeletal organization and root morphology. In seedlings gravistimulated by rotating the culture plates by 90°, both U73122 and neomycin disrupted the normal gravitropic growth of roots and etiolated hypocotyls. The effects of PLC inhibitors are therefore consistent with the notion that, as with phospholipases A and D, PLC likewise interacts with the cytoskeleton, alters growth morphology, and is involved in gravitropism.

  2. The Ca2+ pump inhibitor, thapsigargin, inhibits root gravitropism in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    DANIELA C URBINA

    2006-01-01

    Full Text Available Thapsigargin, a specific inhibitor of most animal intracellular SERCA-type Ca2+ pumps present in the sarcoplasmic/endoplasmic reticulum, was originally isolated from the roots of the Mediterranean plant Thapsia gargancia L. Here, we demonstrate that this root-derived compound is capable of altering root gravitropism in Arabidopsis thaliana. Thapsigargin concentrations as low as 0.1 µM alter root gravitropism whereas under similar conditions cyclopiazonic acid does not. Furthermore, a fluorescently conjugated thapsigargin (BODIPY FL thapsigargin suggests that target sites for thapsigargin are located in intracellular organelles in the root distal elongation zone and the root cap, regions known to regulate root gravitropism

  3. Inhibition of polar calcium movement and gravitropism in roots treated with auxin-transport inhibitors

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    Lee, J. S.; Mulkey, T. J.; Evans, M. L.

    1984-01-01

    Primary roots of maize (Zea mays L.) and pea (Pisum sativum L.) exhibit strong positive gravitropism. In both species, gravistimulation induces polar movement of calcium across the root tip from the upper side to the lower side. Roots of onion (Allium cepa L.) are not responsive to gravity and gravistimulation induces little or no polar movement of calcium across the root tip. Treatment of maize or pea roots with inhibitors of auxin transport (morphactin, naphthylphthalamic acid, 2,3,5-triiodobenzoic acid) prevents both gravitropism and gravity-induced polar movement of calcium across the root tip. The results indicate that calcium movement and auxin movement are closely linked in roots and that gravity-induced redistribution of calcium across the root cap may play an important role in the development of gravitropic curvature.

  4. Characterization of a calcium/calmodulin-dependent protein kinase homolog from maize roots showing light-regulated gravitropism

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    Lu, Y. T.; Hidaka, H.; Feldman, L. J.

    1996-01-01

    Roots of many species respond to gravity (gravitropism) and grow downward only if illuminated. This light-regulated root gravitropism is phytochrome-dependent, mediated by calcium, and inhibited by KN-93, a specific inhibitor of calcium/calmodulin-dependent protein kinase II (CaMK II). A cDNA encoding MCK1, a maize homolog of mammalian CaMK, has been isolated from roots of maize (Zea mays L.). The MCK1 gene is expressed in root tips, the site of perception for both light and gravity. Using the [35S]CaM gel-overlay assay we showed that calmodulin-binding activity of the MCK1 is abolished by 50 microM KN-93, but binding is not affected by 5 microM KN-93, paralleling physiological findings that light-regulated root gravitropism is inhibited by 50 microM KN-93, but not by 5 microM KN-93. KN-93 inhibits light-regulated gravitropism by interrupting transduction of the light signal, not light perception, suggesting that MCK1 may play a role in transducing light. This is the first report suggesting a physiological function for a CaMK homolog in light signal transduction.

  5. Root growth, secondary root formation and root gravitropism in carotenoid-deficient seedlings of Zea mays L

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    Ng, Y. K.; Moore, R.

    1985-01-01

    The effect of ABA on root growth, secondary-root formation and root gravitropism in seedlings of Zea mays was investigated by using Fluridone-treated seedlings and a viviparous mutant, both of which lack carotenoids and ABA. Primary roots of seedlings grown in the presence of Fluridone grew significantly slower than those of control (i.e. untreated) roots. Elongation of Fluridone-treated roots was inhibited significantly by the exogenous application of 1 mM ABA. Exogenous application of 1 micromole and 1 nmole ABA had either no effect or only a slight stimulatory effect on root elongation, depending on the method of application. The absence of ABA in Fluridone-treated plants was not an important factor in secondary-root formation in seedlings less than 9-10 d old. However, ABA may suppress secondary-root formation in older seedlings, since 11-d-old control seedlings had significantly fewer secondary roots than Fluridone-treated seedlings. Roots of Fluridone-treated and control seedlings were graviresponsive. Similar data were obtained for vp-9 mutants of Z. mays, which are phenotypically identical to Fluridone-treated seedlings. These results indicate that ABA is necessary for neither secondary-root formation nor for positive gravitropism by primary roots.

  6. Effects of abscisic acid and xanthoxin on elongation and gravitropism in primary roots of Zea mays

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    Lee, J. S.; Hasenstein, K. H.; Mulkey, T. J.; Yang, R. L.; Evans, M. L.

    1990-01-01

    We examined the involvement of abscisic acid (ABA) and xanthoxin (Xan) in maize root gravitropism by (1) testing the ability of ABA to allow positive gravitropism in dark-grown seedlings of the maize cultivar LG11, a cultivar known to require light for positive gravitropism of the primary root, (2) comparing curvature in roots in which half of the cap had been excised and replaced with agar containing either ABA or indole-3-acetic acid (IAA), (3) measuring gravitropism in roots of seedlings submerged in oxygenated solutions of ABA or IAA and (4) testing the effect of Xan on root elongation. Using a variety of methods of applying ABA to the root, we found that ABA did not cause horizontally-oriented primary roots of dark-grown seedlings to become positively gravitropic. Replacing half of the root cap of vertically oriented roots with an agar block containing ABA had little or no effect on curvature relative to that of controls in which the half cap was replaced by a plain agar block. Replacement of the removed half cap with IAA either canceled or reversed the curvature displayed by controls. When light-grown seedlings were submerged in ABA they responded strongly to gravistimulation while those in IAA did not. Xan (up to 0.1 mM) did not affect root elongation. The results indicate that ABA is not a likely mediator of root gravitropism and that the putative ABA precursor, Xan, lacks the appropriate growth-inhibiting properties to serve as a mediator of root gravitropism.

  7. The effect of the external medium on the gravitropic curvature of rice (Oryza sativa, Poaceae) roots

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    Staves, M. P.; Wayne, R.; Leopold, A. C.

    1997-01-01

    The roots of rice seedlings, growing in artificial pond water, exhibit robust gravitropic curvature when placed perpendicular to the vector of gravity. To determine whether the statolith theory (in which intracellular sedimenting particles are responsible for gravity sensing) or the gravitational pressure theory (in which the entire protoplast acts as the gravity sensor) best accounts for gravity sensing in rice roots, we changed the physical properties of the external medium with impermeant solutes and examined the effect on gravitropism. As the density of the external medium is increased, the rate of gravitropic curvature decreases. The decrease in the rate of gravicurvature cannot be attributed to an inhibition of growth, since rice roots grown in 100 Osm/m3 (0.248 MPa) solutions of different densities all support the same root growth rate but inhibit gravicurvature increasingly with increasing density. By contrast, the sedimentation rate of amyloplasts in the columella cells is unaffected by the external density. These results are consistent with the gravitational pressure theory of gravity sensing, but cannot be explained by the statolith theory.

  8. Early development and gravitropic response of lateral roots in Arabidopsis thaliana.

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    Guyomarc'h, S; Léran, S; Auzon-Cape, M; Perrine-Walker, F; Lucas, M; Laplaze, L

    2012-06-05

    Root system architecture plays an important role in determining nutrient and water acquisition and is modulated by endogenous and environmental factors, resulting in considerable developmental plasticity. The orientation of primary root growth in response to gravity (gravitropism) has been studied extensively, but little is known about the behaviour of lateral roots in response to this signal. Here, we analysed the response of lateral roots to gravity and, consistently with previous observations, we showed that gravitropism was acquired slowly after emergence. Using a lateral root induction system, we studied the kinetics for the appearance of statoliths, phloem connections and auxin transporter gene expression patterns. We found that statoliths could not be detected until 1 day after emergence, whereas the gravitropic curvature of the lateral root started earlier. Auxin transporters modulate auxin distribution in primary root gravitropism. We found differences regarding PIN3 and AUX1 expression patterns between the lateral root and the primary root apices. Especially PIN3, which is involved in primary root gravitropism, was not expressed in the lateral root columella. Our work revealed new developmental transitions occurring in lateral roots after emergence, and auxin transporter expression patterns that might explain the specific response of lateral roots to gravity.

  9. Enhanced gravitropism of roots with a disrupted cap actin cytoskeleton

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    Hou, Guichuan; Mohamalawari, Deepti R.; Blancaflor, Elison B.

    2003-01-01

    The actin cytoskeleton has been proposed to be a major player in plant gravitropism. However, understanding the role of actin in this process is far from complete. To address this problem, we conducted an analysis of the effect of Latrunculin B (Lat B), a potent actin-disrupting drug, on root gravitropism using various parameters that included detailed curvature kinetics, estimation of gravitropic sensitivity, and monitoring of curvature development after extended clinorotation. Lat B treatment resulted in a promotion of root curvature after a 90 degrees reorientation in three plant species tested. More significantly, the sensitivity of maize (Zea mays) roots to gravity was enhanced after actin disruption, as determined from a comparison of presentation time of Lat B-treated versus untreated roots. A short 10-min gravistimulus followed by extended rotation on a 1-rpm clinostat resulted in extensive gravitropic responses, manifested as curvature that often exceeded 90 degrees. Application of Lat B to the cap or elongation zone of maize roots resulted in the disruption of the actin cytoskeleton, which was confined to the area of localized Lat B application. Only roots with Lat B applied to the cap displayed the strong curvature responses after extended clinorotation. Our study demonstrates that disrupting the actin cytoskeleton in the cap leads to the persistence of a signal established by a previous gravistimulus. Therefore, actin could function in root gravitropism by providing a mechanism to regulate the proliferation of a gravitropic signal originating from the cap to allow the root to attain its correct orientation or set point angle.

  10. Inhibitory effects of KN-93, an inhibitor of Ca2+ calmodulin-dependent protein kinase II, on light-regulated root gravitropism in maize

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    Feldman, L. J.; Hidaka, H.

    1993-01-01

    Light is essential for root gravitropism in Zea mays L., cultivar Merit. It is hypothesized that calcium mediates this light-regulated response. KN-93, an inhibitor of calcium/calmodulin kinase II (CaMK II), inhibits light-regulated root gravitropism but does not affect light perception. We hypothesize that CaMK II, or a homologue, operates late in the light/gravity signal transduction chain. Here we provide evidence suggesting a possible physiological involvement of CaMK II in root gravitropism in plants.

  11. Amyloplast Distribution Directs a Root Gravitropic Reaction

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    Kordyum, Elizabeth

    Immobile higher plants are oriented in the gravitational field due to gravitropim that is a physiological growth reaction and consists of three phases: reception of a gravitational signal by statocytes, its transduction to the elongation zone, and finally the organ bending. As it is known, roots are characterized with positive gravitropism, i. e. they grow in the direction of a gravitational vector, stems - with negative gravitropism, i. e. they grow in the direction opposite to a gravitational vector. According to the Nemec’s and Haberlandt’s starch-statolith hypothesis, amyloplasts in diameter of 1.5 - 3 μ in average, which appear to act as gravity sensors and fulfill a statolythic function in the specialized graviperceptive cells - statocytes, sediment in the direction of a gravitational vector in the distal part of a cell, while a nucleus is in the proximal one. There are reasonable data that confirm the amyloplasts-statoliths participation in gravity perception: 1) correlation between the statoliths localization and the site of gravity sensing, 2) significant redistribution (sedimentation) of amyloplasts in statocytes under gravistimulation in comparison with other cell organelles, 3) root decreased ability to react on gravity under starch removal from amyloplasts, 4) starchless Arabidopsis thaliana mutants are agravitropic, 5) amyloplasts-statoliths do not sediment in the absence of the gravitational vector and are in different parts or more concentrated in the center of statocytes. Plant tropisms have been intensively studied for many decades and continue to be investigated. Nevertheless, the mechanisms by which plants do so is still not clearly explained and many questions on gravisensing and graviresponse remain unanswered. Even accepted hypotheses are now being questioned and recent data are critically evaluated. Although the available data show the Ca2+ and cytoskeleton participation in graviperception and signal transduction, the clear evidence

  12. Genetic analysis of the gravitropic set-point angle in lateral roots of arabidopsis

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    Mullen, J. L.; Hangarter, R. P.

    2003-05-01

    Research on gravity responses in plants has mostly focused on primary roots and shoots, which typically orient to a vertical orientation. However, the distribution of lateral organs and their characteristically non-vertical growth orientation are critical for the determination of plant form. For example, in Arabidopsis, when lateral roots emerge from the primary root, they grow at a nearly horizontal orientation. As they elongate, the roots slowly curve until they eventually reach a vertical orientation. The regulation of this lateral root orientation is an important component affecting overall root system architecture. We found that this change in orientation is not simply due to the onset of gravitropic competence, as non-vertical lateral roots are capable of both positive and negative gravitropism. Thus, the horizontal growth of new lateral roots appears to be determined by what is called the gravitropic set-point angle (GSA). This developmental control of the GSA of lateral roots in Arabidopsis provides a useful system for investigating the components involved in regulating gravitropic responses. Using this system, we have identified several Arabidopsis mutants that have altered lateral root orientations but maintain normal primary root orientation.

  13. Exogenous hydrogen peroxide reversibly inhibits root gravitropism and induces horizontal curvature of primary root during grass pea germination.

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    Jiang, Jinglong; Su, Miao; Wang, Liyan; Jiao, Chengjin; Sun, Zhengxi; Cheng, Wei; Li, Fengmin; Wang, Chongying

    2012-04-01

    During germination in distilled water (dH(2)O) on a horizontally positioned Petri dish, emerging primary roots of grass pea (Lathyrus sativus L.) grew perpendicular to the bottom of the Petri dish, due to gravitropism. However, when germinated in exogenous hydrogen peroxide (H(2)O(2)), the primary roots grew parallel to the bottom of the Petri dish and asymmetrically, forming a horizontal curvature. Time-course experiments showed that the effect was strongest when H(2)O(2) was applied prior to the emergence of the primary root. H(2)O(2) failed to induce root curvature when applied post-germination. Dosage studies revealed that the frequency of primary root curvature was significantly enhanced with increased H(2)O(2) concentrations. This curvature could be directly counteracted by dimethylthiourea (DMTU), a scavenger of H(2)O(2), but not by diphenylene iodonium (DPI) and pyridine, inhibitors of H(2)O(2) production. Exogenous H(2)O(2) treatment caused both an increase in the activities of H(2)O(2)-scavenging enzymes [including ascorbate peroxidase (APX: EC 1.11.1.11), catalase (CAT: EC 1.11.1.6) and peroxidase (POD: EC 1.11.1.7)] and a reduction in endogenous H(2)O(2) levels and root vitality. Although grass pea seeds absorbed exogenous H(2)O(2) during seed germination, DAB staining of paraffin sections revealed that exogenous H(2)O(2) only entered the root epidermis and not inner tissues. These data indicated that exogenously applied H(2)O(2) could lead to a reversible loss of the root gravitropic response and a horizontal curvature in primary roots during radicle emergence of the seedling. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  14. Distribution of Endogenous NO Regulates Early Gravitropic Response and PIN2 Localization in Arabidopsis Roots

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    Ramiro París

    2018-04-01

    Full Text Available High-resolution and automated image analysis of individual roots demonstrated that endogenous nitric oxide (NO contribute significantly to gravitropism of Arabidopsis roots. Lowering of endogenous NO concentrations strongly reduced and even reversed gravitropism, resulting in upward bending, without affecting root growth rate. Notably, the asymmetric accumulation of NO along the upper and lower sides of roots correlated with a positive gravitropic response. Detection of NO by the specific DAF-FM DA fluorescent probe revealed that NO was higher at the lower side of horizontally-oriented roots returning to initial values 2 h after the onset of gravistimulation. We demonstrate that NO promotes plasma membrane re-localization of PIN2 in epidermal cells, which is required during the early root gravitropic response. The dynamic and asymmetric localization of both auxin and NO is critical to regulate auxin polar transport during gravitropism. Our results collectively suggest that, although auxin and NO crosstalk occurs at different levels of regulation, they converge in the regulation of PIN2 membrane trafficking in gravistimulated roots, supporting the notion that a temporally and spatially coordinated network of signal molecules could participate in the early phases of auxin polar transport during gravitropism.

  15. Gravitropism interferes with hydrotropism via counteracting auxin dynamics in cucumber roots: clinorotation and spaceflight experiments.

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    Morohashi, Keita; Okamoto, Miki; Yamazaki, Chiaki; Fujii, Nobuharu; Miyazawa, Yutaka; Kamada, Motoshi; Kasahara, Haruo; Osada, Ikuko; Shimazu, Toru; Fusejima, Yasuo; Higashibata, Akira; Yamazaki, Takashi; Ishioka, Noriaki; Kobayashi, Akie; Takahashi, Hideyuki

    2017-09-01

    Roots of land plants show gravitropism and hydrotropism in response to gravity and moisture gradients, respectively, for controlling their growth orientation. Gravitropism interferes with hydrotropism, although the mechanistic aspects are poorly understood. Here, we differentiated hydrotropism from gravitropism in cucumber roots by conducting clinorotation and spaceflight experiments. We also compared mechanisms regulating hydrotropism and auxin-regulated gravitropism. Clinorotated or microgravity (μG)-grown cucumber seedling roots hydrotropically bent toward wet substrate in the presence of moisture gradients, but they grew straight in the direction of normal gravitational force at the Earth's surface (1G) on the ground or centrifuge-generated 1G in space. The roots appeared to become hydrotropically more sensitive to moisture gradients under μG conditions in space. Auxin transport inhibitors significantly reduced the hydrotropic response of clinorotated seedling roots. The auxin efflux protein CsPIN5 was differentially expressed in roots of both clinorotated and μG-grown seedlings; with higher expression in the high-humidity (concave) side than the low-humidity (convex) side of hydrotropically responding roots. Our results suggest that roots become hydrotropically sensitive in μG, and CsPIN5-mediated auxin transport has an important role in inducing root hydrotropism. Thus, hydrotropic and gravitropic responses in cucumber roots may compete via differential auxin dynamics established in response to moisture gradients and gravity. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  16. The microtubule cytoskeleton does not integrate auxin transport and gravitropism in maize roots

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    Hasenstein, K. H.; Blancaflor, E. B.; Lee, J. S.

    1999-01-01

    The Cholodny-Went hypothesis of gravitropism suggests that the graviresponse is controlled by the distribution of auxin. However, the mechanism of auxin transport during the graviresponse of roots is still unresolved. To determine whether the microtubule (MT) cytoskeleton is participating in auxin transport, the cytoskeleton was examined and the movement of 3H-IAA measured in intact and excised taxol, oryzalin, and naphthylphthalamic acid (NPA)-treated roots of Zea mays cv. Merit. Taxol and oryzalin did not inhibit the graviresponse of roots but the auxin transport inhibitor NPA greatly inhibited both auxin transport and graviresponse. NPA had no effect on MT organization in vertical roots, but caused MT reorientation in horizontally placed roots. Regardless of treatment, the organization of MTs in intact roots differed from that in root segments. The MT inhibitors, taxol and oryzalin had opposite effects on the MTs, namely, depolymerization (oryzalin) and stabilization and thickening (taxol), but both treatments caused swelling of the roots. The data indicate that the MT cytoskeleton does not directly interfere with auxin transport or auxin-mediated growth responses in maize roots.

  17. Characterizing pathways by which gravitropic effectors could move from the root cap to the root of primary roots of Zea mays

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    Moore, R.; McClelen, C. E.

    1989-01-01

    Plasmodesmata linking the root cap and root in primary roots Zea mays are restricted to approx. 400 protodermal cells bordering approx. 110000 microns2 of the calyptrogen of the root cap. This area is less than 10% of the cross-sectional area of the root-tip at the cap junction. Therefore, gravitropic effectors moving from the root cap to the root can move symplastically only through a relatively small area in the centre of the root. Decapped roots are non-responsive to gravity. However, decapped roots whose caps are replaced immediately after decapping are strongly graviresponsive. Thus, gravicurvature occurs only when the root cap contacts the root, and symplastic continuity between the cap and root is not required for gravicurvature. Completely removing mucilage from the root tip renders the root non-responsive to gravity. Taken together, these data suggest that gravitropic effectors move apoplastically through mucilage from the cap to the root.

  18. Gravitropic reaction of primary seminal roots of Zea mays L. influenced by temperature and soil water potential.

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    Nakamoto, T

    1995-03-01

    The growth of the primary seminal root of maize (Zea mays L.) is characterized by an initial negative gravitropic reaction and a later positive one that attains a plagiotropic liminal angle. The effects of temperature and water potential of the surrounding soil on these gravitropic reactions were studied. Temperatures of 32, 25, and 18C and soil water potentials of -5, -38, and -67 kPa were imposed and the direction of growth was measured for every 1 cm length of the root. The initial negative gravitropic reaction extended to a distance of about 10 cm from the grain. Higher temperatures reduced the initial negative gravitropic reaction. Lower soil water potential induced a downward growth at root emergence. A mathematical model, in which it was assumed that the rate of the directional change of root growth was a sum of a time-dependent negative gravitropic reaction and an establishment of the liminal angle, adequately fitted the distance-angle relations. It was suggested that higher temperatures and/or a lower water potential accelerated the diminution of the initial negative gravitropic reaction.

  19. Early development and gravitropic response of lateral roots in Arabidopsis thaliana

    OpenAIRE

    Guyomarc'h, S.; Leran, S.; Auzon-Cape, M.; Perrine-Walker, F.; Lucas, Mikaël; Laplaze, Laurent

    2012-01-01

    Root system architecture plays an important role in determining nutrient and water acquisition and is modulated by endogenous and environmental factors, resulting in considerable developmental plasticity. The orientation of primary root growth in response to gravity (gravitropism) has been studied extensively, but little is known about the behaviour of lateral roots in response to this signal. Here, we analysed the response of lateral roots to gravity and, consistently with previous observati...

  20. Actin cytoskeleton rearrangements in Arabidopsis roots under stress and during gravitropic response

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    Pozhvanov, Gregory; Medvedev, Sergei; Suslov, Dmitry; Demidchik, Vadim

    Among environmental factors, gravity vector is the only one which is constant in direction and accompanies the whole plant ontogenesis. That said, gravity vector can be considered as an essential factor for correct development of plants. Gravitropism is a plant growth response against changing its position relative to the gravity vector. It is well estableshed that gravitropism is directed by auxin redistribution across the gravistimulated organ. In addition to auxin, actin cytoskeleton was shown to be involved in gravitropism at different stages: gravity perception, signal transduction and gravitropic bending formation. However, the relationship between IAA and actin is still under discussion. In this work we studied rearrangements of actin cytoskeleton during root gravitropic response. Actin microfilaments were visualized in vivo in GFP-fABD2 transgenic Arabidopsis plants, and their angle distribution was acquired from MicroFilament Analyzer software. The curvature of actin microfilaments in root elongation zone was shown to be increased within 30-60 min of gravistimulation, the fraction of axially oriented microfilaments decreased with a concomitant increase in the fraction of oblique and transversally oriented microfilaments. In particular, the fraction of transversally oriented microfilaments (i.e. parallel to the gravity vector) increased 3-5 times. Under 10 min of sub-lethal salt stress impact, actin microfilament orientations widened from an initial axial orientation to a set of peaks at 15(°) , 45(°) and 90(°) . We conclude that the actin cytoskeleton rearrangements observed are associated with the regulation of basic mechanisms of cell extension growth by which the gravitropic bending is formed. Having common stress-related features, gravity-induced actin cytoskeleton rearrangement is slower but results in higher number of g-vector-parallel microfilaments when compared to salt stress-induced rearrangement. Also, differences in gravistimulated root

  1. Comparative effects of auxin and abscisic acid on growth, hydrogen ion efflux and gravitropism in primary roots of maize

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    Evans, M. L.; Mulkey, T. J.

    1984-01-01

    In order to test the idea that auxin action on root growth may be mediated by H(+) movement, the correlation of auxin action on growth and H(+) movement in roots was examined along with changes in H(+) efflux patterns associated with the asymmetric growth which occurs during gravitropism. The effects of indoleacetic acid (IAA) and abscisic acid (AbA) on growth, H(+) secretion, and gravitropism in roots were compared. Results show a close correlation existent between H(+) efflux and growth in maize roots. In intact roots there is strong H(+) efflux from the elongation zone. Growth-promoting concentrations of IAA stimulate H(+) efflux. During gravitropism the H(+) efflux from the elongation zone becomes asymmetric; the evidence indicates that auxin redistribution contributes to the development of acid efflux asymmetry. That AbA stimulates root growth is reflected in its ability to stimulate H(+) efflux from apical root segments.

  2. Auxin-induced nitric oxide, cGMP and gibberellins were involved in the gravitropism

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    Cai, Weiming; Hu, Liwei; Hu, Xiangyang; Cui, Dayong; Cai, Weiming

    Gravitropism is the asymmetric growth or curvature of plant organs in response to gravistimulation. There is a complex signal transduction cascade which involved in the differential growth of plants in response to changes in the gravity vector. The role of auxin in gravitropism has been demonstrated by many experiments, but little is known regarding the molecular details of such effects. In our studies before, mediation of the gravitropic bending of soybean roots and rice leaf sheath bases by nitric oxide, cGMP and gibberellins, are induced by auxin. The asymmetrical distribution of nitric oxide, cGMP and gibberellins resulted from the asymmetrical synthesis of them in bending sites. In soybean roots, inhibitions of NO and cGMP synthesis reduced differential NO and cGMP accumulation respectively, which both of these effects can lead to the reduction of gravitropic bending. Gibberellin-induced OsXET, OsEXPA4 and OsRWC3 were also found involved in the gravitropic bending. These data indicated that auxin-induced nitric oxide, cGMP and gibberellins were involved in the gravitropism. More experiments need to prove the more detailed mechanism of them.

  3. Changes in root gravitropism, ultrastructure, and calcium balance of pea root statocytes induced by A23187

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    Belyavskaya, N.

    The role for calcium in the regulation of a wide variety of cellular events in plants is well known. Calcium signaling has been implicated in plant gravitropism. A carboxylic acid antibiotic A23187 (calcimycin) has been widely used in biological studies since it can translocate calcium across membranes. Seedlings of Pisum sativum L. cv. Uladovsky germinated in a vertically oriented cylinder of moist filter paper soaked in water during 4.5 day had been treated with 10-5 M A23187 for 12 hr. Tips of primary roots of control and A23187-treated pea seedlings were fixed for electron microscopy and electron cytochemistry. Experiments with Pisum sativum 5- day seedlings placed horizontally for 4 h after treatment with 10 μM A23187 during 12 h found that the graviresponsiveness of their primary roots was lost completely (91 % of roots) or inhibited (24 +/- 6° in comparison with 88 +/- 8° in control). At ultrastructural level, there were observed distribution of amyloplasts around the nucleus, remarkable lengthening of statocytes, advanced vacuolization, changes in dictyosome structure, ER fragmentation, cell wall thinning in A23187-treated statocytes. Cytochemical study has indicated that statocytes exposed to calcimycin have contained a number of Ca-pyroantimonate granules detected Ca 2 + ions in organelles and hyaloplasm (unlike the control ones). The deposits were mainly associated with the plasma membrane. Among organelles, mitochondria were notable for their ability to accumulate Ca 2 +. In amyloplasts, a fine precipitate was predominately located in their stroma and envelope lumens. In cell walls, deposits of the reaction product were observed along the periphery and in the median zone. Localization of electron-dense granules of lead phosphate, which indicated Ca 2 +- ATPase activities in pea statocytes exposed to A23187, was generally consistent with that in untreated roots. Apart from plasma membrane, chromatin, and nucleolus components, the cytochemical reaction

  4. Callose deposition during gravitropism of Zea mays and Pisum sativum and its inhibition by 2-deoxy-D-glucose

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    Jaffe, M. J.; Leopold, A. C.

    1984-01-01

    In etiolated corn (Zea mays L.) and etiolated pea (Pisum sativum L.) seedlings, a gravitropic stimulation induces the deposition of callose. In the corn coleoptiles this occurs within 5 min of gravity stimulation, and prior to the beginning of curvature. Both gravitropic curvature and callose deposition reach their maxima by 12 h. Within the first 2 h more callose is deposited on the upper (concave) side, but after 2-3 h, this deposition pattern is reversed. An inhibitor of protein glycosylation, 2-deoxy-D-glucose (DDG), inhibits callose production and considerably retards gravitropic bending in both species of plants. Mannose can relieve the inhibition of gravitropic bending by DDG. The pea mutant "Ageotropum", which does not respond to gravity when etiolated, also fails to produce callose in response to a gravitic stimulus. These correlations indicate that callose deposition may be a biochemical component of gravitropism in plant shoots.

  5. Changes in cytosolic pH within Arabidopsis root columella cells play a key role in the early signaling pathway for root gravitropism

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    Scott, A. C.; Allen, N. S.; Davies, E. (Principal Investigator)

    1999-01-01

    Ratiometric wide-field fluorescence microscopy with 1',7'- bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF)-dextran demonstrated that gravistimulation leads to rapid changes in cytoplasmic pH (pHc) in columella cells of Arabidopsis roots. The pHc of unstimulated columella cells in tiers 2 and 3, known sites of graviperception (E.B. Blancaflor, J.B. Fasano, S. Gilroy [1998] Plant Physiol 116: 213-222), was 7.22 +/- 0.02 pH units. Following gravistimulation, the magnitude and direction of pHc changes in these cells depended on their location in the columella. Cells in the lower side of tier 2 became more alkaline by 0.4 unit within 55 s of gravistimulation, whereas alkalinization of the cells on the upper side was slower (100 s). In contrast, all cells in tier 3 acidified by 0.4 pH unit within 480 s after gravistimulation. Disrupting these pHc changes in the columella cells using pHc modifiers at concentrations that do not affect root growth altered the gravitropic response. Acidifying agents, including bafilomycin A1, enhanced curvature, whereas alkalinizing agents disrupted gravitropic bending. These results imply that pHc changes in the gravisensing cells and the resultant pH gradients across the root cap are important at an early stage in the signal cascade leading to the gravitropic response.

  6. Collection of gravitropic effectors from mucilage of electrotropically-stimulated roots of Zea mays L

    Science.gov (United States)

    Fondren, W. M.; Moore, R.

    1987-01-01

    We placed agar blocks adjacent to tips of electrotropically stimulated primary roots of Zea mays. Blocks placed adjacent to the anode-side of the roots for 3 h induced significant curvature when subsequently placed asymmetrically on tips of vertically-oriented roots. Curvature was always toward the side of the root unto which the agar block was placed. Agar blocks not contacting roots and blocks placed adjacent to the cathode-side of electrotropically stimulated roots did not induce significant curvature when placed asymmetrically on tips of vertically-oriented roots. Atomic absorption spectrophotometry indicated that blocks adjacent to the anode-side of electrotropically-stimulated roots contained significantly more calcium than (1) blocks not contacting roots, and (2) blocks contacting the cathode-side of roots. These results demonstrate the presence of a gradient of endogenous Ca in mucilage of electrotropically-stimulated roots (i.e. roots undergoing gravitropic-like curvature).

  7. Apoplastic pH in corn root gravitropism: a laser scanning confocal microscopy measurement

    International Nuclear Information System (INIS)

    Taylor, D.P.; Slattery, J.; Leopold, A.C.

    1996-01-01

    The ability to measure the pH of the apoplast in situ is of special interest as a test of the cell wall acidification theory. Optical sectioning of living seedlings of corn roots using the laser scanning confocal microscope (LSCM) permits us to make pH measurements in living tissue. The pH of the apoplast of corn roots was measured by this method after infiltration with CI-NERF, a pH-sensitive dye, along with Texas Red Dextran 3000, a pH-insensitive dye, as an internal standard. In the elongation zone of corn roots, the mean apoplastic pH was 4.9. Upon gravitropic stimulation, the pH on the convex side of actively bending roots was 4.5. The lowering of the apoplastic pH by 0.4 units appears to be sufficient to account for the increased growth on that side. This technique provides site-specific evidence for the acid growth theory of cell elongation. The LSCM permits measurements of the pH of living tissues, and has a sensitivity of approximately 0.2 pH units. (author)

  8. Genetics of the gravitropic set-point angle in lateral organs of Arabidopsis

    Science.gov (United States)

    Mullen, J.; Hangarter, R.

    Research on gravity responses in plants has mostly focused on primary roots and shoots, which typically orient to a vertical orientation. However, the distribution of lateral organs and their typically non-vertical growth orientation are critical for the determination of plant form. For example, in Arabidopsis, when lateral roots emerge from the primary root, they grow at a nearly horizontal orientation. As they elongate, the roots slowly curve until they eventually reach a vertical orientation. The regulation of this lateral root orientation is an important component affecting the overall root system architecture. We found that this change in orientation is not simply due to the onset of gravitropic competence, as non-vertical lateral roots are capable of both positive and negative gravitropism. Thus, the horizontal growth the new lateral roots is determined by what is called the gravitropic set-point angle (GSA). This developmental control of the GSA of lateral roots in Arabidopsis provides a useful system for investigating the components involved in regulating gravitropic responses. Using this system, we have identified several Arabidopsis mutants that have altered lateral root orientations but maintain normal primary root orientation. Two of these mutants also have altered orientation of their rosette leaves, indicating some common mechanisms in the positioning of root and shoot lateral organs. Rosette leaves and lateral roots also have in common a regulation of orientation by red light that may be due to red-light-dependent changes in the GSA. Further molecular and physiological analyses of the GSA mutants will provide insight into the basis of GSA regulation and, thus, a better understanding of how gravity controls plant architecture. [This work was supported by the National Aeronautics and Space Administration through grant no. NCC 2-1200.

  9. Analysis of growth patterns during gravitropic curvature in roots of Zea mays by use of a computer-based video digitizer

    Science.gov (United States)

    Nelson, A. J.; Evans, M. L.

    1986-01-01

    A computer-based video digitizer system is described which allows automated tracking of markers placed on a plant surface. The system uses customized software to calculate relative growth rates at selected positions along the plant surface and to determine rates of gravitropic curvature based on the changing pattern of distribution of the surface markers. The system was used to study the time course of gravitropic curvature and changes in relative growth rate along the upper and lower surface of horizontally-oriented roots of maize (Zea mays L.). The growing region of the root was found to extend from about 1 mm behind the tip to approximately 6 mm behind the tip. In vertically-oriented roots the relative growth rate was maximal at about 2.5 mm behind the tip and declined smoothly on either side of the maximum. Curvature was initiated approximately 30 min after horizontal orientation with maximal (50 degrees) curvature being attained in 3 h. Analysis of surface extension patterns during the response indicated that curvature results from a reduction in growth rate along both the upper and lower surfaces with stronger reduction along the lower surface.

  10. Correlations between gravitropic curvature and auxin movement across gravistimulated roots of Zea mays

    Science.gov (United States)

    Young, L. M.; Evans, M. L.; Hertel, R.

    1990-01-01

    We compared the kinetics of auxin redistribution across the caps of primary roots of 2-day-old maize (Zea mays, cv Merit) seedlings with the time course of gravitropic curvature. [3H] indoleacetic acid was applied to one side of the cap in an agar donor and radioactivity moving across the cap was collected in an agar receiver applied to the opposite side. Upon gravistimulation the roots first curved upward slightly, then returned to the horizontal and began curving downward, reaching a final angle of about 67 degrees. Movement of label across the caps of gravistimulated roots was asymmetric with preferential downward movement (ratio downward/upward = ca. 1.6, radioactivity collected during the 90 min following beginning of gravistimulation). There was a close correlation between the development of asymmetric auxin movement across the root cap and the rate of curvature, with both values increasing to a maximum and then declining as the roots approached the final angle of curvature. In roots preadapted to gravity (alternate brief stimulation on opposite flanks over a period of 1 hour) the initial phase of upward curvature was eliminated and downward bending began earlier than for controls. The correlation between asymmetric auxin movement and the kinetics of curvature also held in comparisons between control and preadapted roots. Both downward auxin transport asymmetry and downward curvature occurred earlier in preadapted roots than in controls. These findings are consistent with suggestions that the root cap is not only the site of perception but also the location of the initial redistribution of effectors that ultimately leads to curvature.

  11. Regulation of auxin transport during gravitropism

    Science.gov (United States)

    Rashotte, A.; Brady, S.; Kirpalani, N.; Buer, C.; Muday, G.

    Plants respond to changes in the gravity vector by differential growth across the gravity-stimulated organ. The plant hormone auxin, which is normally basipetally transported, changes in direction and auxin redistribution has been suggested to drive this differential growth or gravitropism. The mechanisms by which auxin transport directionality changes in response to a change in gravity vector are largely unknown. Using the model plant, Arabidopsis thaliana, we have been exploring several regulatory mechanisms that may control auxin transport. Mutations that alter protein phosphorylation suggest that auxin transport in arabidopsis roots may be controlled via phosphorylation and this signal may facilitate gravitropic bending. The protein kinase mutant pinoid (pid9) has reduced auxin transport; whereas the protein phosphatase mutant, rcn1, has elevated transport, suggesting reciprocal regulation of auxin transport by reversible protein phosphorylation. In both of these mutants, the auxin transport defects are accompanied by gravitropic defects, linking phosphorylation signaling to gravity-induced changes in auxin transport. Additionally, auxin transport may be regulated during gravity response by changes in an endogenous auxin efflux inhibitor. Flavonoids, such as quercetin and kaempferol, have been implicated in regulation of auxin transport in vivo and in vitro. Mutants that make no flavonoids have reduced root gravitropic bending. Furthermore, changes in auxin-induced gene expression and flavonoid accumulation patterns have been observed during gravity stimulation. Current studies are examining whether there are spatial and temporal changes in flavonoid accumulation that precede gravitropic bending and whether the absence of these changes are the cause of the altered gravity response in plants with mutations that block flavonoid synthesis. These results support the idea that auxin transport may be regulated during gravity response by several mechanisms including

  12. Activated by Combined Magnrtic Field Gravitropic Reaction Reply on Nanodose of Biologicaly Active Compounds

    Science.gov (United States)

    Sheykina, Nadezhda; Bogatina, Nina

    The new science direction nanotechnologies initiated a big jump in the pharmacology and medicine. This leads to the big development of homeopathy. The most interest appeared while investigating of the reaction of biological object on the nano dose of iologically substances. The changing of concentration (in nmol/l) of biologically active material is also possible during weak energy action. For instance, weak combined magnetic field may change a little the concentration of ions that are oriented parallel to the external magnetic field and, by the analogy with said above, lead to the similar effects. Simple estimations give the value for the threshold to the magnetic field by two orders smaller than the geomagnetic field. By this investigation we wanted to understand whether the analogy in the action of nano dose of biologically active substances and weak combined magnetic field presents and whether the action of one of these factors may be replaced by other one. The effect of one of biologically active substances NPA (Naphtyl-Phtalame Acid) solution with the concentration 0.01 mol/l on the gravitropic reaction of cress roots was investigated. It was shown that its effect was the inhibition of cress roots gravitropic reaction. The same inhibition was achieved by the combined magnetic field action on the cress roots, germinated in water. The alternative component of the combined magnetic field coincided formally with the cyclotron frequency of NPA ions. So the analogy in the action of nano dose of biologically active substances and weak combined magnetic field was shown. The combined magnetic field using allows to decrease sufficiently the dose of biologically active substances. This fact can be of great importance in pharmacy and medicine.

  13. Small RNA Deep Sequencing and the Effects of microRNA408 on Root Gravitropic Bending in Arabidopsis

    Science.gov (United States)

    Li, Huasheng; Lu, Jinying; Sun, Qiao; Chen, Yu; He, Dacheng; Liu, Min

    2015-11-01

    MicroRNA (miRNA) is a non-coding small RNA composed of 20 to 24 nucleotides that influences plant root development. This study analyzed the miRNA expression in Arabidopsis root tip cells using Illumina sequencing and real-time PCR before (sample 0) and 15 min after (sample 15) a 3-D clinostat rotational treatment was administered. After stimulation was performed, the expression levels of seven miRNA genes, including Arabidopsis miR160, miR161, miR394, miR402, miR403, miR408, and miR823, were significantly upregulated. Illumina sequencing results also revealed two novel miRNAsthat have not been previously reported, The target genes of these miRNAs included pentatricopeptide repeat-containing protein and diadenosine tetraphosphate hydrolase. An overexpression vector of Arabidopsis miR408 was constructed and transferred to Arabidopsis plant. The roots of plants over expressing miR408 exhibited a slower reorientation upon gravistimulation in comparison with those of wild-type. This result indicate that miR408 could play a role in root gravitropic response.

  14. Control of gravitropic orientation. I. Non-vertical orientation by primary roots of maize results from decay of competence for orthogravitropic induction

    Science.gov (United States)

    LaMotte, Clifford E.; Pickard, Barbara G.

    2004-01-01

    Plant organs may respond to gravity by vertical (orthogravitropic), oblique (plagiogravitropic) or horizontal (diagravitropic) growth. Primary roots of maize (Zea mays L.) provide a good system for studying such behaviours because they are reportedly capable of displaying all three responses. In current work using maize seedlings of the Silver Queen cultivar, stabilisation of growth at an oblique orientation was commonplace. Hypothetically, plagiogravitropism may be accomplished either by a process we call graded orthogravitropism or by hunting about a sensed non-vertical setpoint. In graded orthotropism primary bending is unidirectional and depends on facilitative stimuli that determine its extent. The hallmark of the setpoint mechanism is restorative curvature of either sign following a displacement; both diagravitropism and orthogravitropism are based on setpoints. Roots settled in a plagiogravitropic orientation were tested with various illumination and displacement protocols designed to distinguish between these two hypotheses. The tests refuted the setpoint hypothesis and supported that of graded orthotropism. No evidence of diagravitropism could be found, thus, earlier claims were likely based on inadequately controlled observations of graded orthotropism. We propose that orthotropism is graded by the sequential action of dual gravity receptors: induction of a vectorial gravitropic response requires gravitational induction of a separate facilitative response, whose decay in the absence of fresh stimuli can brake gravitropism at plagiotropic angles.

  15. Mechanisms of gravitropism in single-celled systems

    Science.gov (United States)

    Greuel, Nicole; Braun, Markus; Hauslage, Jens; Wiemann, Katharina

    higher plant statocytes was also found to be not dependent on mechanical pressure but on direct interactions between gravireceptors and statoliths. In contrast to Chara rhizoids, however, the actin system of higher plant statocytes is not essentially required for gravity-sensing. Parabolic flight experiments and ground controls indicated that disruption of the actin cytoskeleton in root statocytes by using Latrunculin B results in an increased gravisensitivity and in a promoted gravitropic curvature rather than in an inhibition. It is speculated that the actomyosin system in statocytes has a fine-tuning function in the early phases of gravity sensing. Actin in higher plant statocytes may be required to optimize statolith-receptor interactions and to keep the sensing system highly sensitive on one hand, but on the other hand actomyosin-statolith interactions seem to avoid unfavourable responses to only transient stimuli.Investigating the unicellular characean rhizoid has greatly enhanced our understanding of gravity sensing processes in plants and there is increasing evidence that higher plants and characean rhizoids share common processes in the signalling pathway of gravity-oriented growth.

  16. Identification and analysis of novel genes involved in gravitropism of Arabidopsis thaliana.

    Science.gov (United States)

    Morita, Miyo T.; Tasaka, Masao; Masatoshi Taniguchi, .

    2012-07-01

    Gravitropism is a continuous control with regard to the orientation and juxtaposition of the various parts of the plant body in response to gravity. In higher plants, the relative directional change of gravity is mainly suscepted in specialized cells called statocytes, followed by signal conversion from physical information into physiological information within the statocytes. We have studied the early process of shoot gravitropism, gravity sensing and signaling process, mainly by molecular genetic approach. In Arabidopsis shoot, statocytes are the endodermal cells. sgr1/scarcrow (scr) and sgr7/short-root (shr) mutants fail to form the endodermis and to respond to gravity in their inflorescence stems. Since both SGR1/SCR and SGR7/SHR are transcriptional factors, at least a subset of their downstream genes can be expected to be involved in gravitropism. In addition, eal1 (endodermal-amyloplast less 1), which exhibits no gravitropism in inflorescence stem but retains ability to form endodermis, is a hypomorphic allele of sgr7/shr. Take advantage of these mutants, we performed DNA microarray analysis and compared gene expression profiles between wild type and the mutants. We found that approx. 40 genes were commonly down-regulated in these mutants and termed them DGE (DOWN-REGULATED GENE IN EAL1) genes. DGE1 has sequence similarity to Oryza sativa LAZY1 that is involved in shoot gravitropism of rice. DGE2 has a short region homologous to DGE1. DTL (DGE TWO-LIKE}) that has 54% identity to DGE2 is found in Arabidopsis genome. All three genes are conserved in angiosperm but have no known functional domains or motifs. We analyzed T-DNA insertion for these genes in single or multiple combinations. In dge1 dge2 dtl triple mutant, gravitropic response of shoot, hypocotyl and root dramatically reduced. Now we are carrying out further physiological and molecular genetic analysis of the triple mutant.

  17. Assessing potential targets of calcium action in light-modulated gravitropism

    Science.gov (United States)

    Roux, S. J.

    1995-01-01

    Light, through the mediation of the pigment phytochrome, modulates the gravitropic response of the shoots and roots of many plants. The transduction of both light and gravity stimuli appears to involve Ca(2+)-regulated steps, one or more of which may represent points of intersection between the two transduction chains. To be confident that Ca2+ plays a critical role in stimulus-response coupling for gravitropism, it will be important to identify specific targets of Ca2+ action whose function can be clearly linked to the regulation of growth. Calcium typically exerts its influence on cell metabolism through binding to and activating key regulatory proteins. The three best characterized of these proteins in plants are the calmodulins, calcium-dependent protein kinases, and annexins. In this review we summarize what is known about the structure and function of these proteins and speculate on how their activation by Ca2+ could influence the differential growth response of gravitropism.

  18. Protein synthesis in geostimulated root caps

    Science.gov (United States)

    Feldman, L. J.

    1982-01-01

    A study is presented of the processes occurring in the root cap of corn which are requisite for the formation of root cap inhibitor and which can be triggered or modulated by both light and gravity. The results of this study indicate the importance of protein synthesis for light-induced gravitropic bending in roots. Root caps in which protein synthesis is prevented are unable to induce downward bending. This suggests that light acts by stimulating proteins which are necessary for the translation of the gravitropic stimulus into a growth response (downward bending). The turnover of protein with time was also examined in order to determine whether light acts by stimulating the synthesis of unique proteins required for downward growth. It is found that auxin in combination with light allows for the translation of the gravitropic stimulus into a growth response at least in part through the modification of protein synthesis. It is concluded that unique proteins are stimulated by light and are involved in promoting the downward growth in roots which are responding to gravity.

  19. The involvement of ethylene in regulation of Arabidopsis gravitropism

    Science.gov (United States)

    Li, Ning; Zhu, Lin

    Plant gravitropism is a directional response to gravity stimulus. This response involves a com-plex signaling network. Ethylene, a major plant hormone, has been found to modulate grav-itropism. The biosynthesis of ethylene is induced by the gravi-stimulus and the requirement for ethylene during gravitropism is tissue-dependent. While ethylene plays a modulating role in inflorescence stems, the light-grown hypocotyls of Arabidopsis requires ethylene to achieve a maximum gravicurvature. Because both inhibitory and stimulatory effects of ethylene on gravitropism have been overwhelmingly documented, there is a need to postulate a new theory to consolidate the apparently contradictory results. A dual-and-opposing effects (DOE) theory is therefore hypothesized to address how ethylene is involved in regulation of Arabidopsis grav-itropism, in which it is suggested that both stimulatory and inhibitory effects act on the same organ of a plant and co-exist at the same time in a mutually opposing manner. The final out-come of gravitropic response is determined by the dynamic display between the two opposing effects. A prolonged pretreatment of ethylene promotes the gravitropism in both inflorescence and light-grown hypocotyls, while a short ethylene pretreatment inhibits gravitropism. Gener-ally speaking, the inhibitory effect of ethylene is dominant over the expression of the stimula-tory effect in light-grown hypocotyls, whereas the stimulatory effect is dominant in inflorescence stem. Each effect is also positively correlated with concentrations of ethylene and in a time-dependent manner. The stimulatory effect occurs slowly but continues to react after the removal of ethylene, whereas the inhibitory effect takes place abruptly and diminishes shortly after its removal. Forward genetic screening based on the DOE phenotype of ethylene-treated Arabidop-sis has revealed a novel component in gravity signaling pathway: EGY1 (ethylene-dependent gravitropism-deficient and yellow

  20. Disruption of the actin cytoskeleton results in the promotion of gravitropism in inflorescence stems and hypocotyls of Arabidopsis

    Science.gov (United States)

    Yamamoto, Kazuyoshi; Kiss, John Z.

    2002-01-01

    The actin cytoskeleton is hypothesized to play a major role in gravity perception and transduction mechanisms in roots of plants. To determine whether actin microfilaments (MFs) are involved in these processes in stem-like organs, we studied gravitropism in Arabidopsis inflorescence stems and hypocotyls. Localization studies using Alexa Fluor-phalloidin in conjugation with confocal microscopy demonstrated a longitudinally and transversely oriented actin MF network in endodermal cells of stems and hypocotyls. Latrunculin B (Lat-B) treatment of hypocotyls caused depolymerization of actin MFs in endodermal cells and a significant reduction of hypocotyl growth rates. Actin MFs in Lat-B-treated inflorescence stems also were disrupted, but growth rates were not affected. Despite disruption of the actin cytoskeleton in these two organs, Lat-B-treated stems and hypocotyls exhibited a promotion of gravitropic curvature in response to reorientation. In contrast, Lat-B reduced gravitropic curvature in roots but also reduced the growth rate. Thus, in contrast to prevailing hypotheses, our results suggest that actin MFs are not a necessary component of gravitropism in inflorescence stems and hypocotyls. Furthermore, this is the first study to demonstrate a prominent actin MF network in endodermal cells in the putative gravity-perceiving cells in stems.

  1. New moss species with gravitropic protonemata

    Science.gov (United States)

    Lobachevska, O. V.

    Gravitropism of 30 moss species was analysed at different stages of development: germination of spores, protonemata, gametophore and sporophyte formation. Spores were sowed in sterile conditions from the closed capsules on 1 % bactoagar with 0,2 % glucose and cultivated in the dark in vertically oriented petri dishes. In the same conditions fragments of protonemata and gametophores were grown being transferred aseptically from sterile cultures of spores germinated in controled light conditions. To assess gravity sensitivity the dishes were kept upright for 7 10 days in darkness and then 90o turned. After 20 h gravistimulation the angles of apical cell gravity bending were determined. The amount of amyloplasts and their distribution during growth and spatial reorientation of sporophytes selected from nature samples on different stages of species-specific capsule formation were analyzed after JK2J staining. The gravitropic sensing was established in 7 new moss species only. The general traits of all such species were the ark-like cygneous seta bending and inclined, to pendulous, capsules. JK2J staining of young isolated sporophytes has shown, that twisting and bending of seta as well as the spatial capsule reorientation result from the changes of distribution of amyloplasts in the direction of gravitropic growth or caused by their lateral sedimentation. In the dark protonemata of investigated mosses grew upwards on agar surface giving rise to bundles of negatively gravitropic stolons in 7-10 days. During germination at first negatively gravitropic primary chloronema and then positively gravitropic primary rizoid appeared. In 3 days, however, the growth of all primary filaments was negatively gravitropic. In Dicranella cerviculata majority of primary filaments were negatively gravitropic from the very beginning. After 20 h gravistimulation of protonemata of different moss species the following mean values of gravity bending (degrees) were established: Leptobryum

  2. Graviresponsiveness of surgically altered primary roots of Zea mays

    Science.gov (United States)

    Maimon, E.; Moore, R.

    1991-01-01

    We examined the gravitropic responses of surgically altered primary roots of Zea mays to determine the route by which gravitropic inhibitors move from the root tip to the elongating zone. Horizontally oriented roots, from which a 1-mm-wide girdle of epidermis plus 2-10 layers of cortex were removed from the apex of the elongating zone, curve downward. However, curvature occurred only apical to the girdle. Filling the girdle with mucilage-like material transmits curvature beyond the girdle. Vertically oriented roots with a half-girdle' (i.e. the epidermis and 2-10 layers of the cortex removed from half of the circumference of the apex of the elongating zone) curve away from the girdle. Inserting the half-girdle at the base of the elongating zone induces curvature towards the girdle. Filling the half-circumference girdles with mucilage-like material reduced curvature significantly. Stripping the epidermis and outer 2-5 layers of cortex from the terminal 1.5 cm of one side of a primary root induces curvature towards the cut, irrespective of the root's orientation to gravity. This effect is not due to desiccation since treated roots submerged in water also curved towards their cut surface. Coating a root's cut surface with a mucilage-like substance minimizes curvature. These results suggest that the outer cell-layers of the root, especially the epidermis, play an important role in root gravicurvature, and the gravitropic signals emanating from the root tip can move apoplastically through mucilage.

  3. Inhibition of ethylene production by putrescine alleviates aluminium-induced root inhibition in wheat plants.

    Science.gov (United States)

    Yu, Yan; Jin, Chongwei; Sun, Chengliang; Wang, Jinghong; Ye, Yiquan; Zhou, Weiwei; Lu, Lingli; Lin, Xianyong

    2016-01-08

    Inhibition of root elongation is one of the most distinct symptoms of aluminium (Al) toxicity. Although putrescine (Put) has been identified as an important signaling molecule involved in Al tolerance, it is yet unknown how Put mitigates Al-induced root inhibition. Here, the possible mechanism was investigated by using two wheat genotypes differing in Al resistance: Al-tolerant Xi Aimai-1 and Al-sensitive Yangmai-5. Aluminium caused more root inhibition in Yangmai-5 and increased ethylene production at the root apices compared to Xi Aimai-1, whereas the effects were significantly reversed by ethylene biosynthesis inhibitors. The simultaneous exposure of wheat seedlings to Al and ethylene donor, ethephon, or ethylene biosynthesis precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), increased ethylene production and aggravated root inhibition, which was more pronounced in Xi Aimai-1. In contrast, Put treatment decreased ethylene production and alleviated Al-induced root inhibition in both genotypes, and the effects were more conspicuous in Yangmai-5. Furthermore, our results indicated that Al-induced ethylene production was mediated by ACC synthase (ACS) and ACC oxidase, and that Put decreased ethylene production by inhibiting ACS. Altogether, these findings indicate that ethylene is involved in Al-induced root inhibition and this process could be alleviated by Put through inhibiting ACS activity.

  4. Jasmonic Acid Enhances Al-Induced Root Growth Inhibition.

    Science.gov (United States)

    Yang, Zhong-Bao; He, Chunmei; Ma, Yanqi; Herde, Marco; Ding, Zhaojun

    2017-02-01

    Phytohormones such as ethylene and auxin are involved in the regulation of the aluminum (Al)-induced root growth inhibition. Although jasmonate (JA) has been reported to play a crucial role in the regulation of root growth and development in response to environmental stresses through interplay with ethylene and auxin, its role in the regulation of root growth response to Al stress is not yet known. In an attempt to elucidate the role of JA, we found that exogenous application of JA enhanced the Al-induced root growth inhibition. Furthermore, phenotype analysis with mutants defective in either JA biosynthesis or signaling suggests that JA is involved in the regulation of Al-induced root growth inhibition. The expression of the JA receptor CORONATINE INSENSITIVE1 (COI1) and the key JA signaling regulator MYC2 was up-regulated in response to Al stress in the root tips. This process together with COI1-mediated Al-induced root growth inhibition under Al stress was controlled by ethylene but not auxin. Transcriptomic analysis revealed that many responsive genes under Al stress were regulated by JA signaling. The differential responsive of microtubule organization-related genes between the wild-type and coi1-2 mutant is consistent with the changed depolymerization of cortical microtubules in coi1 under Al stress. In addition, ALMT-mediated malate exudation and thus Al exclusion from roots in response to Al stress was also regulated by COI1-mediated JA signaling. Together, this study suggests that root growth inhibition is regulated by COI1-mediated JA signaling independent from auxin signaling and provides novel insights into the phytohormone-mediated root growth inhibition in response to Al stress. © 2017 American Society of Plant Biologists. All Rights Reserved.

  5. Changes in root cap pH are required for the gravity response of the Arabidopsis root

    Science.gov (United States)

    Fasano, J. M.; Swanson, S. J.; Blancaflor, E. B.; Dowd, P. E.; Kao, T. H.; Gilroy, S.

    2001-01-01

    Although the columella cells of the root cap have been identified as the site of gravity perception, the cellular events that mediate gravity signaling remain poorly understood. To determine if cytoplasmic and/or wall pH mediates the initial stages of root gravitropism, we combined a novel cell wall pH sensor (a cellulose binding domain peptide-Oregon green conjugate) and a cytoplasmic pH sensor (plants expressing pH-sensitive green fluorescent protein) to monitor pH dynamics throughout the graviresponding Arabidopsis root. The root cap apoplast acidified from pH 5.5 to 4.5 within 2 min of gravistimulation. Concomitantly, cytoplasmic pH increased in columella cells from 7.2 to 7.6 but was unchanged elsewhere in the root. These changes in cap pH preceded detectable tropic growth or growth-related pH changes in the elongation zone cell wall by 10 min. Altering the gravity-related columella cytoplasmic pH shift with caged protons delayed the gravitropic response. Together, these results suggest that alterations in root cap pH likely are involved in the initial events that mediate root gravity perception or signal transduction.

  6. Isolation of New Gravitropic Mutants under Hypergravity Conditions.

    Science.gov (United States)

    Mori, Akiko; Toyota, Masatsugu; Shimada, Masayoshi; Mekata, Mika; Kurata, Tetsuya; Tasaka, Masao; Morita, Miyo T

    2016-01-01

    Forward genetics is a powerful approach used to link genotypes and phenotypes, and mutant screening/analysis has provided deep insights into many aspects of plant physiology. Gravitropism is a tropistic response in plants, in which hypocotyls and stems sense the direction of gravity and grow upward. Previous studies of gravitropic mutants have suggested that shoot endodermal cells in Arabidopsis stems and hypocotyls are capable of sensing gravity (i.e., statocytes). In the present study, we report a new screening system using hypergravity conditions to isolate enhancers of gravitropism mutants, and we also describe a rapid and efficient genome mapping method, using next-generation sequencing (NGS) and single nucleotide polymorphism (SNP)-based markers. Using the endodermal-amyloplast less 1 ( eal1 ) mutant, which exhibits defective development of endodermal cells and gravitropism, we found that hypergravity (10 g) restored the reduced gravity responsiveness in eal1 hypocotyls and could, therefore, be used to obtain mutants with further reduction in gravitropism in the eal1 background. Using the new screening system, we successfully isolated six ene ( enhancer of eal1 ) mutants that exhibited little or no gravitropism under hypergravity conditions, and using NGS and map-based cloning with SNP markers, we narrowed down the potential causative genes, which revealed a new genetic network for shoot gravitropism in Arabidopsis .

  7. The cytoskeleton and gravitropism in higher plants

    Science.gov (United States)

    Blancaflor, Elison B.

    2002-01-01

    The cellular and molecular mechanisms underlying the gravitropic response of plants have continued to elude plant biologists despite more than a century of research. Lately there has been increased attention on the role of the cytoskeleton in plant gravitropism, but several controversies and major gaps in our understanding of cytoskeletal involvement in gravitropism remain. A major question in the study of plant gravitropism is how the cytoskeleton mediates early sensing and signal transduction events in plants. Much has been made of the actin cytoskeleton as the cellular structure that sedimenting amyloplasts impinge upon to trigger the downstream signaling events leading to the bending response. There is also strong molecular and biochemical evidence that the transport of auxin, an important player in gravitropism, is regulated by actin. Organizational changes in microtubules during the growth response phase of gravitropism have also been well documented, but the significance of such reorientations in controlling differential cellular growth is unclear. Studies employing pharmacological approaches to dissect cytoskeletal involvement in gravitropism have led to conflicting results and therefore need to be interpreted with caution. Despite the current controversies, the revolutionary advances in molecular, biochemical, and cell biological techniques have opened up several possibilities for further research into this difficult area. The myriad proteins associated with the plant cytoskeleton that are being rapidly characterized provide a rich assortment of candidate regulators that could be targets of the gravity signal transduction chain. Cytoskeletal and ion imaging in real time combined with mutant analysis promises to provide a fresh start into this controversial area of research.

  8. Effects of norflurazon, an inhibitor of carotenogenesis, on abscisic acid and xanthoxin in the caps of gravistimulated maize roots

    Science.gov (United States)

    Feldman, L. J.; Sun, P. S.

    1986-01-01

    Maize seeds were germinated in the dark in the presence of the carotenoid synthesis inhibitor norflurazon and the levels of abscisic acid, xanthoxin and total carotenoids were measured in the root cap and in the adjacent 1.5 mm segment. In norflurazon-treated roots abscisic acid levels were markedly reduced, but an increase occurred in the levels of xanthoxin, a compound structurally and physiologically similar to abscisic acid. In the cultivar of maize (Zea mays L. cv. Merit) used for this work, brief illumination of the root is required for gravitropic curving. Following illumination both control and norflurazon-treated roots showed normal gravitropic curvature; however, the rate of curvature was delayed in norflurazon-treated roots. Our data from norflurazon-treated roots are consistent with a role for xanthoxin in maize root gravitropism. The increase in xanthoxin in the presence of an inhibitor of carotenoid synthesis suggests that xanthoxin and abscisic acid originate, at least in part, via different metabolic pathways.

  9. Isolation of new gravitropic mutants under hypergravity conditions

    Directory of Open Access Journals (Sweden)

    Akiko Mori

    2016-09-01

    Full Text Available Forward genetics is a powerful approach used to link genotypes and phenotypes, and mutant screening/analysis has provided deep insights into many aspects of plant physiology. Gravitropism is a tropistic response in plants, in which hypocotyls and stems sense the direction of gravity and grow upwards. Previous studies of gravitropic mutants have suggested that shoot endodermal cells in Arabidopsis stems and hypocotyls are capable of sensing gravity (i.e., statocytes. In the present study, we report a new screening system using hypergravity conditions to isolate enhancers of gravitropism mutants, and we also describe a rapid and efficient genome mapping method, using Next-Generation Sequencing (NGS and Single Nucleotide Polymorphism (SNP-based markers. Using the endodermal-amyloplast less 1 (eal1 mutant, which exhibits defective development of endodermal cells and gravitropism, we found that hypergravity (10 g restored the reduced gravity responsiveness in eal1 hypocotyls and could, therefore, be used to obtain mutants with further reduction in gravitropism in the eal1 background. Using the new screening system, we successfully isolated six ene (enhancer of eal1 mutants that exhibited little or no gravitropism under hypergravity conditions, and using NGS and map-based cloning with SNP markers, we narrowed down the potential causative genes, which revealed a new genetic network for shoot gravitropism in Arabidopsis.

  10. The persistence of the gravity signal in flax roots

    Science.gov (United States)

    Hasenstein, Karl H.

    Although the presentation time of gravitropism has been studied, no data exist as to how long a reorientation stimulus affects the gravitropic response of a root. We tested the duration of gravitropic curvature in roots of Linum usitatissimum after reversing a one hour, 90 degree gravistimulus by increasing time intervals in vertical orientation before clinorotating the roots and acquiring infrared digital images. Clinorotation was performed either parallel or perpendicular to the gravity vector. Under either condition the gravistimulus affected curvature during clinorotation only between two to three minutes. Maximal curvature after one minute of vertical reorientation was 15 degrees within one hour. After three minutes in vertical orientation the observed curvature was not statistically different from vertically growing roots. In both orientations, maximum curvature occurred after 1hr. Perpendicular (horizontal) clinorotation showed decreasing curvature with increasing reorientation time. Parallel (vertical) clinorotation resulted in greater variability to the reorientation time. These data indicate that the gravity stimulus operates essentially memory free and that clinorotation affects the gravity response. Therefore all aspects of clinorotation need to be studied before an assessment of clinostats for the simulation of microgravity is possible and a time limit for memory effects of mechanostimulation can be determined.

  11. Exogenous nitrate induces root branching and inhibits primary root growth in Capsicum chinense Jacq.

    Science.gov (United States)

    Celis-Arámburo, Teresita de Jesús; Carrillo-Pech, Mildred; Castro-Concha, Lizbeth A; Miranda-Ham, María de Lourdes; Martínez-Estévez, Manuel; Echevarría-Machado, Ileana

    2011-12-01

    The effects of nitrate (NO₃⁻) on the root system are complex and depend on several factors, such as the concentration available to the plant, endogenous nitrogen status and the sensitivity of the species. Though these effects have been widely documented on Arabidopsis and cereals, no reports are available in the Capsicum genus. In this paper, we have determined the effect of an exogenous in vitro application of this nutrient on root growth in habanero pepper (Capsicum chinense Jacq.). Exposure to NO₃⁻ inhibited primary root growth in both, dose- and time-dependent manners. The highest inhibition was attained with 0.1 mM NO₃⁻ between the fourth and fifth days of treatment. Inhibition of primary root growth was observed by exposing the root to both homogeneous and heterogeneous conditions of the nutrient; in contrast, ammonium was not able to induce similar changes. NO₃⁻-induced inhibition of primary root growth was reversed by treating the roots with IAA or NPA, a polar auxin transport inhibitor. Heterogeneous NO₃⁻ application stimulated the formation and elongation of lateral roots in the segment where the nutrient was present, and this response was influenced by exogenous phytohormones. These results demonstrate that habanero pepper responds to NO₃⁻ in a similar fashion to other species with certain particular differences. Therefore, studies in this model could help to elucidate the mechanisms by which roots respond to NO₃⁻ in fluctuating soil environments. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  12. Gravitropism in caulonemata of the moss Pottia intermedia

    Science.gov (United States)

    Chaban, C. I.; Kern, V. D.; Ripetskyj, R. T.; Demkiv, O. T.; Sack, F. D.

    1998-01-01

    The gravitropism of caulonemata of Pottia intermedia is described and compared with that of other mosses. Spore germination produces primary protonemata including caulonemata which give rise to buds that form the leafy moss plant, the gametophore. Primary caulonemata are negatively gravitropic but their growth and the number of filaments are limited in the dark. Axenic culture of gametophores results in the production of secondary caulonemata that usually arise near the leaf base. Secondary protonemata that form in the light are agravitropic. Secondary caulonemata that form when gametophores are placed in the dark for several days show strong negative gravitropism and grow well in the dark. When upright caulonemata are reorientated to the horizontal or are inverted, upward bending can be detected after 1 h and caulonemata reach the vertical within 1-2 d. Clear amyloplast sedimentation occurs 10-15 minutes after horizontal placement and before the start of upward curvature. This sedimentation takes place in a sub-apical zone. Amyloplast sedimentation also takes place along the length of upright and inverted Pottia protonemata. These results support the hypothesis that amyloplast sedimentation functions in gravitropic sensing since sedimentation occurs before gravitropism in Pottia and since the location and presence of a unique sedimentation zone is conserved in all four mosses known to gravitropic protonomata.

  13. Gravity sensing and signal transduction in vascular plant primary roots.

    Science.gov (United States)

    Baldwin, Katherine L; Strohm, Allison K; Masson, Patrick H

    2013-01-01

    During gravitropism, the potential energy of gravity is converted into a biochemical signal. How this transfer occurs remains one of the most exciting mysteries in plant cell biology. New experiments are filling in pieces of the puzzle. In this review, we introduce gravitropism and give an overview of what we know about gravity sensing in roots of vascular plants, with special highlight on recent papers. When plant roots are reoriented sideways, amyloplast resedimentation in the columella cells is a key initial step in gravity sensing. This process somehow leads to cytoplasmic alkalinization of these cells followed by relocalization of auxin efflux carriers (PINs). This changes auxin flow throughout the root, generating a lateral gradient of auxin across the cap that upon transmission to the elongation zone leads to differential cell elongation and gravibending. We will present the evidence for and against the following players having a role in transferring the signal from the amyloplast sedimentation into the auxin signaling cascade: mechanosensitive ion channels, actin, calcium ions, inositol trisphosphate, receptors/ligands, ARG1/ARL2, spermine, and the TOC complex. We also outline auxin transport and signaling during gravitropism.

  14. Isolation of a novel mutant gene for soil-surface rooting in rice (Oryza sativa L.).

    Science.gov (United States)

    Hanzawa, Eiko; Sasaki, Kazuhiro; Nagai, Shinsei; Obara, Mitsuhiro; Fukuta, Yoshimichi; Uga, Yusaku; Miyao, Akio; Hirochika, Hirohiko; Higashitani, Atsushi; Maekawa, Masahiko; Sato, Tadashi

    2013-11-20

    Root system architecture is an important trait affecting the uptake of nutrients and water by crops. Shallower root systems preferentially take up nutrients from the topsoil and help avoid unfavorable environments in deeper soil layers. We have found a soil-surface rooting mutant from an M2 population that was regenerated from seed calli of a japonica rice cultivar, Nipponbare. In this study, we examined the genetic and physiological characteristics of this mutant. The primary roots of the mutant showed no gravitropic response from the seedling stage on, whereas the gravitropic response of the shoots was normal. Segregation analyses by using an F2 population derived from a cross between the soil-surface rooting mutant and wild-type Nipponbare indicated that the trait was controlled by a single recessive gene, designated as sor1. Fine mapping by using an F2 population derived from a cross between the mutant and an indica rice cultivar, Kasalath, revealed that sor1 was located within a 136-kb region between the simple sequence repeat markers RM16254 and 2935-6 on the terminal region of the short arm of chromosome 4, where 13 putative open reading frames (ORFs) were found. We sequenced these ORFs and detected a 33-bp deletion in one of them, Os04g0101800. Transgenic plants of the mutant transformed with the genomic fragment carrying the Os04g0101800 sequence from Nipponbare showed normal gravitropic responses and no soil-surface rooting. These results suggest that sor1, a rice mutant causing soil-surface rooting and altered root gravitropic response, is allelic to Os04g0101800, and that a 33-bp deletion in the coding region of this gene causes the mutant phenotypes.

  15. Shoot-supplied ammonium targets the root auxin influx carrier AUX1 and inhibits lateral root emergence in Arabidopsis

    KAUST Repository

    Li, Baohai

    2011-03-24

    Deposition of ammonium (NH4 +) from the atmosphere is a substantial environmental problem. While toxicity resulting from root exposure to NH4 + is well studied, little is known about how shoot-supplied ammonium (SSA) affects root growth. In this study, we show that SSA significantly affects lateral root (LR) development. We show that SSA inhibits lateral root primordium (LRP) emergence, but not LRP initiation, resulting in significantly impaired LR number. We show that the inhibition is independent of abscisic acid (ABA) signalling and sucrose uptake in shoots but relates to the auxin response in roots. Expression analyses of an auxin-responsive reporter, DR5:GUS, and direct assays of auxin transport demonstrated that SSA inhibits root acropetal (rootward) auxin transport while not affecting basipetal (shootward) transport or auxin sensitivity of root cells. Mutant analyses indicated that the auxin influx carrier AUX1, but not the auxin efflux carriers PIN-FORMED (PIN)1 or PIN2, is required for this inhibition of LRP emergence and the observed auxin response. We found that AUX1 expression was modulated by SSA in vascular tissues rather than LR cap cells in roots. Taken together, our results suggest that SSA inhibits LRP emergence in Arabidopsis by interfering with AUX1-dependent auxin transport from shoot to root. © 2011 Blackwell Publishing Ltd.

  16. Influence of electrical fields and asymmetric application of mucilage on curvature of primary roots of Zea mays

    Science.gov (United States)

    Marcum, H.; Moore, R.

    1990-01-01

    Primary roots of Zea mays cv. Yellow Dent growing in an electric field curve towards the anode. Roots treated with EDTA and growing in electric field do not curve. When root cap mucilage is applied asymmetrically to tips of vertically-oriented roots, the roots curve toward the mucilage. Roots treated with EDTA curve toward the side receiving mucilage and toward blocks containing 10 mM CaCl2, but not toward "empty" agar blocks or the cut surfaces of severed root tips. These results suggest that 1) free calcium (Ca) is necessary for root electrotropism, 2) mucilage contains effector(s) that induce gravitropiclike curvature, and 3) mucilage can replace gravitropic effectors chelated by EDTA. These results are consistent with the hypothesis that the downward movement of gravitropic effectors to the lower sides of tips of horizontally-oriented roots occurs at least partially in the apoplast.

  17. Adsorption and inhibition of CuO nanoparticles on Arabidopsis thaliana root

    Science.gov (United States)

    Xu, Lina

    2018-02-01

    CuO NPs, the size ranging from 20 to 80 nm were used to detect the adsorption and inhibition on the Arabidopsis thaliana roots. In this study, CuO NPs were adsorbed and agglomerated on the surface of root top after exposed for 7 days. With the increasing of CuO NPs concentrations, CuO NPs also adsorbed on the meristernatic zone. The growth of Arabidopsis thaliana lateral roots were also inhibited by CuO NPs exposure. The Inhibition were concentration dependent. The number of root top were 246, 188 and 123 per Arabidopsis thaliana, respectively. The number of root tops after CuO NPs exposure were significantly decreased compared with control groups. This results suggested the phytotoxicity of CuO NPs on Arabidopsis thaliana roots.

  18. Graviresponsiveness and abscisic-acid content of roots of carotenoid-deficient mutants of Zea mays L

    Science.gov (United States)

    Moore, R.; Smith, J. D.

    1985-01-01

    The abscisic-acid (ABA) content of roots of the carotenoid-deficient w-3, vp-5, and vp-7 mutants of Z. mays was analyzed using gas chromatography-mass spectrometry with an analysis sensitivity of 6 ng ABA g-1 fresh weight (FW). Roots of normal seedlings of the same lines were characterized by the following amounts of ABA (as ng ABA g-1 FW, +/- standard deviation): w-3, 279 +/- 43; vp-5, 237 +/- 26; vp-7, 338 +/- 61. We did not detect any ABA in roots of any of the mutants. Thus, the lack of carotenoids in these mutants correlated positively with the apparent absence of ABA. Primary roots of normal and mutant seedlings were positively gravitropic, with no significant differences in the curvatures of roots of normal as compared with mutant seedlings. These results indicate that ABA 1) is synthesized in maize roots via the carotenoid pathway, and 2) is not necessary for positive gravitropism by primary roots of Z. mays.

  19. Abscisic acid, xanthoxin and violaxanthin in the caps of gravistimulated maize roots

    Science.gov (United States)

    Feldman, L. J.; Arroyave, N. J.; Sun, P. S.

    1985-01-01

    The occurrence and distribution of abscisic acid (ABA), xanthoxin (Xa) and the carotenoid violaxanthin (Va) were investigated in root tips of maize (Zea mays L. cv. Merit). In roots grown in the dark, Va and ABA were present in relatively high amounts in the root cap and in low amounts in the adjacent terminal 1.5 mm of the root. Xanthoxin was present in equal concentrations in both regions. In roots exposed to light, the ABA distribution was reversed, with relatively low levels in the root cap and high levels in the adjacent 1.5-mm segment. Light also caused a decrease in Va in both regions of the root and an increase in Xa, especially in the cap. In the maize cultivar used for this work, light is necessary for gravitropic curving. This response occurs within the same time frame as the light-induced ABA redistribution as well as the changes in the levels of Va and Xa. These data are consistent with a role for ABA in root gravitropism and support the proposal that Xa may arise from the turnover of Va.

  20. Shoot-supplied ammonium targets the root auxin influx carrier AUX1 and inhibits lateral root emergence in Arabidopsis

    KAUST Repository

    Li, Baohai; Li, Qing; Su, Yanhua; Chen, Hao; Xiong, Liming; Mi, Guohua; Kronzucker, Herbert J.; Shi, Weiming

    2011-01-01

    . In this study, we show that SSA significantly affects lateral root (LR) development. We show that SSA inhibits lateral root primordium (LRP) emergence, but not LRP initiation, resulting in significantly impaired LR number. We show that the inhibition

  1. Phytotoxicity of nanoparticles: Inhibition of seed germination and root growth

    Energy Technology Data Exchange (ETDEWEB)

    Lin Daohui [Department of Environmental Science, Zhejiang University, Hangzhou 310028 (China); Department of Plant, Soil and Insect Sciences, University of Massachusetts, Stockbridge Hall, Amherst, MA 01003 (United States); Xing Baoshan [Department of Plant, Soil and Insect Sciences, University of Massachusetts, Stockbridge Hall, Amherst, MA 01003 (United States)], E-mail: bx@pssci.umass.edu

    2007-11-15

    Plants need to be included to develop a comprehensive toxicity profile for nanoparticles. Effects of five types of nanoparticles (multi-walled carbon nanotube, aluminum, alumina, zinc, and zinc oxide) on seed germination and root growth of six higher plant species (radish, rape, ryegrass, lettuce, corn, and cucumber) were investigated. Seed germination was not affected except for the inhibition of nanoscale zinc (nano-Zn) on ryegrass and zinc oxide (nano-ZnO) on corn at 2000 mg/L. Inhibition on root growth varied greatly among nanoparticles and plants. Suspensions of 2000 mg/L nano-Zn or nano-ZnO practically terminated root elongation of the tested plant species. Fifty percent inhibitory concentrations (IC{sub 50}) of nano-Zn and nano-ZnO were estimated to be near 50 mg/L for radish, and about 20 mg/L for rape and ryegrass. The inhibition occurred during the seed incubation process rather than seed soaking stage. These results are significant in terms of use and disposal of engineered nanoparticles. - Engineered nanoparticles can inhibit the seed germination and root growth.

  2. Phytotoxicity of nanoparticles: Inhibition of seed germination and root growth

    International Nuclear Information System (INIS)

    Lin Daohui; Xing Baoshan

    2007-01-01

    Plants need to be included to develop a comprehensive toxicity profile for nanoparticles. Effects of five types of nanoparticles (multi-walled carbon nanotube, aluminum, alumina, zinc, and zinc oxide) on seed germination and root growth of six higher plant species (radish, rape, ryegrass, lettuce, corn, and cucumber) were investigated. Seed germination was not affected except for the inhibition of nanoscale zinc (nano-Zn) on ryegrass and zinc oxide (nano-ZnO) on corn at 2000 mg/L. Inhibition on root growth varied greatly among nanoparticles and plants. Suspensions of 2000 mg/L nano-Zn or nano-ZnO practically terminated root elongation of the tested plant species. Fifty percent inhibitory concentrations (IC 50 ) of nano-Zn and nano-ZnO were estimated to be near 50 mg/L for radish, and about 20 mg/L for rape and ryegrass. The inhibition occurred during the seed incubation process rather than seed soaking stage. These results are significant in terms of use and disposal of engineered nanoparticles. - Engineered nanoparticles can inhibit the seed germination and root growth

  3. Identification of a Gravitropism-Deficient Mutant in Rice

    Directory of Open Access Journals (Sweden)

    He Yan

    2017-03-01

    Full Text Available A gravitropism-deficient mutant M96 was isolated from a mutant bank, generated by ethyl methane sulfonate (EMS mutagenesis of indica rice accession ZJ100. The mutant was characterized as prostrate growth at the beginning of germination, and the prostrate growth phenotype ran through the whole life duration. Tiller angle and tiller number of M96 increased significantly in comparison with the wild type. Tissue section observation analysis indicated that asymmetric stem growth around the second node occurred in M96. Genetic analysis and gene mapping showed that M96 was controlled by a single recessive nuclear gene, tentatively termed as gravitropism-deficient M96 (gdM96, which was mapped to a region of 506 kb flanked by markers RM5960 and InDel8 on the long arm of chromosome 11. Sequencing analysis of the open reading frames in this region revealed a nucleotide substitution from G to T in the third exon of LOC_Os11g29840. Additionally, real-time fluorescence quantitative PCR analysis showed that the expression level of LOC_Os11g29840 in the stems was much higher than in the roots and leaves in M96. Furthermore, the expression level was more than four times in M96 stem than in the wild type stem. Our results suggested that the mutant gene was likely a new allele to the reported gene LAZY1. Isolation of this new allele would facilitate the further characterization of LAZY1.

  4. Isolation of new gravitropic mutants under hypergravity conditions

    OpenAIRE

    Akiko Mori; Masatsugu Toyota; Masatsugu Toyota; Masayoshi Shimada; Mika Mekata; Tetsuya Kurata; Masao Tasaka; Miyo Terao Morita

    2016-01-01

    Forward genetics is a powerful approach used to link genotypes and phenotypes, and mutant screening/analysis has provided deep insights into many aspects of plant physiology. Gravitropism is a tropistic response in plants, in which hypocotyls and stems sense the direction of gravity and grow upwards. Previous studies of gravitropic mutants have suggested that shoot endodermal cells in Arabidopsis stems and hypocotyls are capable of sensing gravity (i.e., statocytes). In the present study, we ...

  5. Effects of ethylene on the kinetics of curvature and auxin redistribution in gravistimulated roots of Zea mays

    Science.gov (United States)

    Lee, J. S.; Evans, M. L.

    1990-01-01

    We tested the involvement of ethylene in maize (Zea mays L.) root gravitropism by measuring the kinetics of curvature and lateral auxin movement in roots treated with ethylene, inhibitors of ethylene synthesis, or inhibitors of ethylene action. In the presence of ethylene the latent period of gravitropic curvature appeared to be increased somewhat. However, ethylene-treated roots continued to curve after control roots had reached their final angle of curvature. Consequently, maximum curvature in the presence of ethylene was much greater in ethylene-treated roots than in controls. Inhibitors of ethylene biosynthesis or action had effects on the kinetics of curvature opposite to that of ethylene, i.e. the latent period appeared to be shortened somewhat while total curvature was reduced relative to that of controls. Label from applied 3H-indole-3-acetic acid was preferentially transported toward the lower side of stimulated roots. In parallel with effects on curvature, ethylene treatment delayed the development of gravity-induced asymmetric auxin movement across the root but extended its duration once initiated. The auxin transport inhibitor, 1-N-naphthylphthalamic acid reduced both gravitropic curvature and the effect of ethylene on curvature. Since neither ethylene nor inhibitors of ethylene biosynthesis or action prevented curvature, we conclude that ethylene does not mediate the primary differential growth response causing curvature. Because ethylene affects curvature and auxin transport in parallel, we suggest that ethylene modifies curvature by affecting gravity-induced lateral transport of auxin, perhaps by interfering with adaptation of the auxin transport system to the gravistimulus.

  6. Isolation of New Gravitropic Mutants under Hypergravity Conditions

    OpenAIRE

    Mori, Akiko; Toyota, Masatsugu; Shimada, Masayoshi; Mekata, Mika; Kurata, Tetsuya; Tasaka, Masao; Morita, Miyo T.

    2016-01-01

    Forward genetics is a powerful approach used to link genotypes and phenotypes, and mutant screening/analysis has provided deep insights into many aspects of plant physiology. Gravitropism is a tropistic response in plants, in which hypocotyls and stems sense the direction of gravity and grow upward. Previous studies of gravitropic mutants have suggested that shoot endodermal cells in Arabidopsis stems and hypocotyls are capable of sensing gravity (i.e., statocytes). In the present study, we r...

  7. Calcium movements and the cellular basis of gravitropism

    Science.gov (United States)

    Roux, S. J.; Biro, R. L.; Hale, C. C.

    An early gravity-transduction event in oat coleoptiles which precedes any noticeable bending is the accumulation of calcium on their prospective slower-growing side. Sub-cellular calcium localization studies indicate that the gravity-stimulated redistribution of calcium results in an increased concentration of calcium in the walls of responding cells. Since calcium can inhibit the extension growth of plant cell walls, this selective accumulation of calcium in walls may play a role in inducing the asymmetry of growth which characterizes gravitropism. The active transport of calcium from cells into walls is performed by a calcium-dependent ATPase localized in the plasma membrane. Evidence is presented in support of the hypothesis that this calcium pump is regulated by a feed-back mechanism which includes the participation of calmodulin.

  8. Piriformospora indica root colonization triggers local and systemic root responses and inhibits secondary colonization of distal roots.

    Science.gov (United States)

    Pedrotti, Lorenzo; Mueller, Martin J; Waller, Frank

    2013-01-01

    Piriformosporaindica is a basidiomycete fungus colonizing roots of a wide range of higher plants, including crop plants and the model plant Arabidopsis thaliana. Previous studies have shown that P. indica improves growth, and enhances systemic pathogen resistance in leaves of host plants. To investigate systemic effects within the root system, we established a hydroponic split-root cultivation system for Arabidopsis. Using quantitative real-time PCR, we show that initial P. indica colonization triggers a local, transient response of several defense-related transcripts, of which some were also induced in shoots and in distal, non-colonized roots of the same plant. Systemic effects on distal roots included the inhibition of secondary P. indica colonization. Faster and stronger induction of defense-related transcripts during secondary inoculation revealed that a P. indica pretreatment triggers root-wide priming of defense responses, which could cause the observed reduction of secondary colonization levels. Secondary P. indica colonization also induced defense responses in distant, already colonized parts of the root. Endophytic fungi therefore trigger a spatially specific response in directly colonized and in systemic root tissues of host plants.

  9. Patterns of auxin and abscisic acid movement in the tips of gravistimulated primary roots of maize

    Science.gov (United States)

    Young, L. M.; Evans, M. L.

    1996-01-01

    Because both abscisic acid (ABA) and auxin (IAA) have been suggested as possible chemical mediators of differential growth during root gravitropism, we compared with redistribution of label from applied 3H-IAA and 3H-ABA during maize root gravitropism and examined the relative basipetal movement of 3H-IAA and 3H-ABA applied to the caps of vertical roots. Lateral movement of 3H-ABA across the tips of vertical roots was non-polar and about 2-fold greater than lateral movement of 3H-IAA (also non-polar). The greater movement of ABA was not due to enhanced uptake since the uptake of 3H-IAA was greater than that of 3H-ABA. Basipetal movement of label from 3H-IAA or 3H-ABA applied to the root cap was determined by measuring radioactivity in successive 1 mm sections behind the tip 90 minutes after application. ABA remained largely in the first mm (point of application) whereas IAA was concentrated in the region 2-4 mm from the tip with substantial levels found 7-8 mm from the tip. Pretreatment with inhibitors of polar auxin transport decreased both gravicurvature and the basipetal movement of IAA. When roots were placed horizontally, the movement of 3H-IAA from top to bottom across the cap was enhanced relative to movement from bottom to top whereas the pattern of movement of label from 3H-ABA was unaffected. These results are consistent with the hypothesis that IAA plays a role in root gravitropism but contrary to the idea that gravi-induced asymmetric distribution of ABA contributes to the response.

  10. Interactions between red light, abscisic acid, and calcium in gravitropism

    Science.gov (United States)

    Leopold, A. C.; LaFavre, A. K.

    1989-01-01

    The effect of red light on orthogravitropism of Merit corn (Zea mays L.) roots has been attributed to its effects on the transduction phase of gravitropism (AC Leopold, SH Wettlaufer [1988] Plant Physiol 87:803-805). In an effort to characterize the orthogravitropic transduction system, comparative experiments have been carried out on the effects of red light, calcium, and abscisic acid (ABA). The red light effect can be completely satisfied with added ABA (100 micromolar) or with osmotic shock, which is presumed to increase endogenous ABA. The decay of the red light effect is closely paralleled by the decay of the ABA effect. ABA and exogenous calcium show strong additive effects when applied to either Merit or a line of corn which does not require red light for orthogravitropism. Measurements of the ABA content show marked increases in endogenous ABA in the growing region of the roots after red light. The interpretation is offered that red light or ABA may serve to increase the cytoplasmic concentrations of calcium, and that this may be an integral part of orthogravitropic transduction.

  11. Inhibiting Cadmium Transport Process in Root Cells of Plants: A Review

    Directory of Open Access Journals (Sweden)

    ZHAO Yan-ling

    2016-05-01

    Full Text Available Cadmium(Cd is the most common element found in the heavy-metal contaminated soils in China. Roots of rice and vegetables can concentrate Cd from acid soils, and then transport Cd to above-ground parts. Cd in edible part of plants directly influences the food safety. Cellwall, plasma membrane and organells of root cells in plant can discriminate Cd from other elements. A lot of Cd can be fixed in root cells by precipitation, complexation, compartmentation, and so on, to inhibit its transport from roots to shoot and guarantee the physiological activities in above-ground parts carrying out normally. This paper summarized recent advance on inhibiting Cd transport process in subcellular fractions of root cells of plants, which is in advantage of exploring excellent germplasms and gene resources in the future.

  12. Root exudates from grafted-root watermelon showed a certain contribution in inhibiting Fusarium oxysporum f. sp. niveum.

    Directory of Open Access Journals (Sweden)

    Ning Ling

    Full Text Available Grafting watermelon onto bottle gourd rootstock is commonly used method to generate resistance to Fusarium oxysporum f. sp. niveum (FON, but knowledge of the effect of the root exudates of grafted watermelon on this soil-borne pathogen in rhizosphere remains limited. To investigate the root exudate profiles of the own-root bottle gourd, grafted-root watermelon and own-root watermelon, recirculating hydroponic culture system was developed to continuously trap these root exudates. Both conidial germination and growth of FON were significantly decreased in the presence of root exudates from the grafted-root watermelon compared with the own-root watermelon. HPLC analysis revealed that the composition of the root exudates released by the grafted-root watermelon differed not only from the own-root watermelon but also from the bottle gourd rootstock plants. We identified salicylic acid in all 3 root exudates, chlorogenic acid and caffeic acid in root exudates from own-root bottle gourd and grafted-root watermelon but not own-root watermelon, and abundant cinnamic acid only in own-root watermelon root exudates. The chlorogenic and caffeic acid were candidates for potentiating the enhanced resistance of the grafted watermelon to FON, therefore we tested the effects of the two compounds on the conidial germination and growth of FON. Both phenolic acids inhibited FON conidial germination and growth in a dose-dependent manner, and FON was much more susceptible to chlorogenic acid than to caffeic acid. In conclusion, the key factor in attaining the resistance to Fusarium wilt is grafting on the non-host root stock, however, the root exudates profile also showed some contribution in inhibiting FON. These results will help to better clarify the disease resistance mechanisms of grafted-root watermelon based on plant-microbe communication and will guide the improvement of strategies against Fusarium-mediated wilt of watermelon plants.

  13. Inducing gravitropic curvature of primary roots of Zea mays cv Ageotropic

    Science.gov (United States)

    Moore, R.; Evans, M. L.; Fondren, W. M.

    1990-01-01

    Primary roots of the mutant 'Ageotropic' cultivar of Zea mays are nonresponsive to gravity. Their root caps secrete little or no mucilage and touch the root only at the extreme apex. A gap separates the cap and root at the periphery of the cap. Applying mucilage from normal roots or substances with a consistency similar to that of mucilage to tips of mutant roots causes these roots to become strongly graviresponsive. Gravicurvature stops when these substances are removed. Caps of some mutants secrete small amounts of mucilage and are graviresponsive. These results indicate that (a) the lack of graviresponsiveness in the mutant results from disrupting the transport pathway between the cap and root, (b) movement of the growth-modifying signal from the cap to the root occurs via an apoplastic pathway, and (c) mucilage is necessary for normal communication between the root cap and root in Zea mays cv Ageotropic.

  14. Sprout inhibition in roots, tubers and bulbs

    International Nuclear Information System (INIS)

    Luna C, P.C.

    1992-05-01

    The treatment with ionizing radiations to low dose impedes that appear sprouts in the tubers (potatoes); bulbs (onion and garlic) and in roots like the ginger and the yucca. The purpose is to inhibit the germination during the process of manipulation and storage, and this way to avoid the lost ones post crop of these products. The radiation dose required to inhibit the germination goes to depend of: the development conditions, the differences of variety, of the storage state of the bulbs and the conditions of cured and storage. (Author)

  15. Inheritance and gene expression of a root-growth inhibiting mutant in rice (Oryza sativa L.)

    International Nuclear Information System (INIS)

    Kitano, H.; Futsuhara, Y.

    1990-01-01

    Full text: A root-growth inhibiting mutant was induced in the dwarf mutant line, 'Fukei 71', through ethylene-imine. The mutant is characterised by the excessive inhibition of both seminal and crown roots elongation just after germination, although its shoots grow nearly normal. To study the genetics, the mutant was crossed with its original line 'Fukei 71' and some other normal cultivars. Results show that the root-growth inhibition is controlled by a recessive gene (rt), independent of the dwarf gene, d-50(t) locus in Fukei 71. For elucidating the gene action on root morphogenesis, histological and cytological experiments were carried out using a longitudinal and transverse thin section of seminal and/or crown root tips. Observations suggest that the rt gene affects the normal formation of the epidermal system which is differentiated from the protoderm of the root apical meristem. (author)

  16. Ethylene Inhibits Cell Proliferation of the Arabidopsis Root Meristem1[OPEN

    Science.gov (United States)

    Street, Ian H.; Aman, Sitwat; Zubo, Yan; Ramzan, Aleena; Wang, Xiaomin; Shakeel, Samina N.; Kieber, Joseph J.; Schaller, G. Eric

    2015-01-01

    The root system of plants plays a critical role in plant growth and survival, with root growth being dependent on both cell proliferation and cell elongation. Multiple phytohormones interact to control root growth, including ethylene, which is primarily known for its role in controlling root cell elongation. We find that ethylene also negatively regulates cell proliferation at the root meristem of Arabidopsis (Arabidopsis thaliana). Genetic analysis indicates that the inhibition of cell proliferation involves two pathways operating downstream of the ethylene receptors. The major pathway is the canonical ethylene signal transduction pathway that incorporates CONSTITUTIVE TRIPLE RESPONSE1, ETHYLENE INSENSITIVE2, and the ETHYLENE INSENSITIVE3 family of transcription factors. The secondary pathway is a phosphorelay based on genetic analysis of receptor histidine kinase activity and mutants involving the type B response regulators. Analysis of ethylene-dependent gene expression and genetic analysis supports SHORT HYPOCOTYL2, a repressor of auxin signaling, as one mediator of the ethylene response and furthermore, indicates that SHORT HYPOCOTYL2 is a point of convergence for both ethylene and cytokinin in negatively regulating cell proliferation. Additional analysis indicates that ethylene signaling contributes but is not required for cytokinin to inhibit activity of the root meristem. These results identify key elements, along with points of cross talk with cytokinin and auxin, by which ethylene negatively regulates cell proliferation at the root apical meristem. PMID:26149574

  17. GRAVI-2 space experiment: investigating statoliths displacement and location effects on early stages of gravity perception pathways in lentil roots.

    Science.gov (United States)

    Bizet, François; Eche, Brigitte; Pereda Loth, Veronica; Badel, Eric; Legue, Valerie; Brunel, Nicole; Label, Philippe; Gérard, Joëlle

    2016-07-01

    The plants ability to orient their growth with respect to external stimuli such as gravity is a key factor for survival and acclimation to their environment. Belowground, plant roots modulate their growth towards gravity, allowing soil exploration and uptake of water and nutrients. In roots, gravity sensing cells called statocytes are located in the center of the root cap. Statocytes contain starch-filled plastids denser than the cytoplasm, which sedimentation along the direction of gravity is widely accepted as being involved into early stages of gravity perception (the starch-statolith hypothesis; Sack, 1991). Root gravitropism following statoliths displacement is based on auxin redistribution in the root apex, inducing differential growth between the root upward and downward sides. However at the cell scale, the chain of transduction starting from statoliths displacement and leading to auxin redistribution remains poorly documented. Signaling molecules such as calcium, reactive oxygen species, nitric oxide and inositol 1,4,5-triphosphate are serious candidates previously shown to be involved within minutes before modification of the expression of auxin-related genes (Morita, 2010; Sato et al., 2015). Here, we observe and quantify statoliths displacements and locations at various levels of gravity to investigate two hypothesis: (i) Are contacts between statoliths and the endoplasmic reticulum necessary to induce gravitropism? (ii) Are very low displacements of statoliths sufficient to initiate transduction pathways such as the calcium's one? These questionings have led to an experiment called GRAVI-2 which took place aboard the ISS in 2014. During the experiment, lentil roots were grown in the European modular cultivation system for several hours in microgravity and were then submitted to short high gravity stimulus (5 and 15 minutes at 2 g) before the return to Earth for analyses. Ongoing cytological measurements will reveal the effects of statoliths

  18. Unifying model of shoot gravitropism reveals proprioception as a central feature of posture control in plants

    DEFF Research Database (Denmark)

    Bastien, Renaud; Bohr, Tomas; Moulia, Bruno

    2012-01-01

    Gravitropism, the slow reorientation of plant growth in response to gravity, is a key determinant of the form and posture of land plants. Shoot gravitropism is triggered when statocysts sense the local angle of the growing organ relative to the gravitational field. Lateral transport of the hormone...... is thus as important as gravisensing in gravitropic control, and the B ratio can be measured as phenotype in genetic studies....

  19. A molecular framework for the inhibition of Arabidopsis root growth in response to boron toxicity.

    Science.gov (United States)

    Aquea, Felipe; Federici, Fernan; Moscoso, Cristian; Vega, Andrea; Jullian, Pastor; Haseloff, Jim; Arce-Johnson, Patricio

    2012-04-01

    Boron is an essential micronutrient for plants and is taken up in the form of boric acid (BA). Despite this, a high BA concentration is toxic for the plants, inhibiting root growth and is thus a significant problem in semi-arid areas in the world. In this work, we report the molecular basis for the inhibition of root growth caused by boron. We show that application of BA reduces the size of root meristems, correlating with the inhibition of root growth. The decrease in meristem size is caused by a reduction of cell division. Mitotic cell number significantly decreases and the expression level of key core cell cycle regulators is modulated. The modulation of the cell cycle does not appear to act through cytokinin and auxin signalling. A global expression analysis reveals that boron toxicity induces the expression of genes related with abscisic acid (ABA) signalling, ABA response and cell wall modifications, and represses genes that code for water transporters. These results suggest that boron toxicity produces a reduction of water and BA uptake, triggering a hydric stress response that produces root growth inhibition. © 2011 Blackwell Publishing Ltd.

  20. Inhibition of tobacco mosaic virus replication in lateral roots is dependent on an activated meristem-derived signal.

    Science.gov (United States)

    Valentine, T A; Roberts, I M; Oparka, K J

    2002-05-01

    Viral invasion of the root system of Nicotiana benthamiana was studied noninvasively with a tobacco mosaic virus (TMV) vector expressing the green-fluorescent protein (GFP). Lateral root primordia, which developed from the pericycle of primary roots, became heavily infected as they emerged from the root cortex. However, following emergence, a progressive wave of viral inhibition occurred that originated in the lateral-root meristem and progressed towards its base. Excision of source and sink tissues suggested that the inhibition of virus replication was brought about by the basipetal movement of a root meristem signal. When infected plants were inoculated with tobacco rattle virus (TRV) expressing the red-fluorescent protein, DsRed, TRV entered the lateral roots and suppressed the host response, leading to a reestablishment of TMV infection in lateral roots. By infecting GFP-expressing transgenic plants with TMV carrying the complementary GFP sequence it was possible to silence the host GFP, leading to the complete loss of fluorescence in lateral roots. The data suggest that viral inhibition in lateral roots occurs by a gene-silencing-like mechanism that is dependent on the activation of a lateral-root meristem.

  1. Actin Cytoskeleton-Based Plant Synapse as Gravitransducer in the Transition Zone of the Root Apex

    Science.gov (United States)

    Baluska, Frantisek; Barlow, Peter; Volkmann, Dieter; Mancuso, Stefano

    The actin cytoskeleton was originally proposed to act as the signal transducer in the plant gravity sensory-motoric circuit. Surprisingly, however, several studies have documented that roots perfom gravisensing and gravitropism more effectively if exposed to diverse anti-F-actin drugs. Our study, using decapped maize root apices, has revealed that depolymerization of F-actin stimulates gravity perception in cells of the transition zone where root gravitropism is initiated (Mancuso et al. 2006). It has been proposed (Balǔka et al. 2005, 2009a) that s the non-growing adhesive end-poles, enriched with F-actin and myosin VIII, and active in endocytic recycling of both PIN transporters and cell wall pectins cross-linked with calcium and boron, act as the gravisensing domains, and that these impinge directly upon the root motoric responses via control of polar auxin transport. This model suggests that mechanical asymmetry at these plant synapses determines vectorial gravity-controlled auxin transport. Due to the gravity-imposed mechanical load upon the protoplast, a tensional stress is also imposed upon the plasma membrane of the physically lower synaptic cell pole. This stress is then relieved by shifting the endocytosis-exocytosis balance towards exocytosis (Balǔka et al. s 2005, 2009a,b). This `Synaptic Auxin Secretion' hypothesis does not conflict with the `Starch Statolith' hypothesis, which is based on amyloplast sedimentation. In fact, the `Synaptic Auxin Secretion' hypothesis has many elements which allow its unification with the Starch-Statolith model (Balǔka et al. 2005, 2009a,b). s References Balǔka F, Volkmann D, Menzel D (2005) Plant synapses: actin-based adhesion s domains for cell-to-cell communication. Trends Plant Sci 10: 106-111 Balǔka F, Schlicht M, s Wan Y-L, Burbach C, Volkmann D (2009a) Intracellular domains and polarity in root apices: from synaptic domains to plant neurobiology. Nova Acta Leopoldina 96: 103-122 Balǔka s F, Mancuso S

  2. Roles of abscisic acid and auxin in shoot-supplied ammonium inhibition of root system development.

    Science.gov (United States)

    Li, Baohai; Li, Qing; Kronzucker, Herbert J; Shi, Weiming

    2011-10-01

    A plastic root system is a prerequisite for successful plant acclimation to variable environments. The normally functioning root system is the result of a complex interaction of root-borne signals and shoot-derived regulators. We recently demonstrated that AUX1, a well-studied component of auxin transport, mediates shoot-supplied ammonium (SSA) inhibition of lateral root (LR) formation in Arabidopsis. By contrast, the response did not involve ABA pathways, via which several other abiotic stresses affect LR formation. We proposed that SSA regulates LR emergence by interrupting AUX1-mediated auxin transport from shoot to root. Here, by analyzing both ABA- and auxin-related mutants, we show that AUX1 is also required for SSA-mediated suppression of primary root growth. Ammonium content in shoots was furthermore shown to increase linearly with shoot-, but not root-supplied, ammonium, suggesting it may represent the internal trigger for SSA inhibition of root development. Taken together, our data identify AUX1-mediated auxin transport as a key transmission step in the sensing of excessive ammonium exposure and its inhibitory effect on root development. 

  3. Sites and regulation of auxin biosynthesis in Arabidopsis roots.

    Science.gov (United States)

    Ljung, Karin; Hull, Anna K; Celenza, John; Yamada, Masashi; Estelle, Mark; Normanly, Jennifer; Sandberg, Göran

    2005-04-01

    Auxin has been shown to be important for many aspects of root development, including initiation and emergence of lateral roots, patterning of the root apical meristem, gravitropism, and root elongation. Auxin biosynthesis occurs in both aerial portions of the plant and in roots; thus, the auxin required for root development could come from either source, or both. To monitor putative internal sites of auxin synthesis in the root, a method for measuring indole-3-acetic acid (IAA) biosynthesis with tissue resolution was developed. We monitored IAA synthesis in 0.5- to 2-mm sections of Arabidopsis thaliana roots and were able to identify an important auxin source in the meristematic region of the primary root tip as well as in the tips of emerged lateral roots. Lower but significant synthesis capacity was observed in tissues upward from the tip, showing that the root contains multiple auxin sources. Root-localized IAA synthesis was diminished in a cyp79B2 cyp79B3 double knockout, suggesting an important role for Trp-dependent IAA synthesis pathways in the root. We present a model for how the primary root is supplied with auxin during early seedling development.

  4. Root evolution at the base of the lycophyte clade: insights from an Early Devonian lycophyte

    Science.gov (United States)

    Matsunaga, Kelly K. S.; Tomescu, Alexandru M. F.

    2016-01-01

    Background and Aims The evolution of complex rooting systems during the Devonian had significant impacts on global terrestrial ecosystems and the evolution of plant body plans. However, detailed understanding of the pathways of root evolution and the architecture of early rooting systems is currently lacking. We describe the architecture and resolve the structural homology of the rooting system of an Early Devonian basal lycophyte. Insights gained from these fossils are used to address lycophyte root evolution and homology. Methods Plant fossils are preserved as carbonaceous compressions at Cottonwood Canyon (Wyoming), in the Lochkovian–Pragian (∼411 Ma; Early Devonian) Beartooth Butte Formation. We analysed 177 rock specimens and documented morphology, cuticular anatomy and structural relationships, as well as stratigraphic position and taphonomic conditions. Key Results The rooting system of the Cottonwood Canyon lycophyte is composed of modified stems that bear fine, dichotomously branching lateral roots. These modified stems, referred to as root-bearing axes, are produced at branching points of the above-ground shoot system. Root-bearing axes preserved in growth position exhibit evidence of positive gravitropism, whereas the lateral roots extend horizontally. Consistent recurrence of these features in successive populations of the plant preserved in situ demonstrates that they represent constitutive structural traits and not opportunistic responses of a flexible developmental programme. Conclusions This is the oldest direct evidence for a rooting system preserved in growth position. These rooting systems, which can be traced to a parent plant, include some of the earliest roots known to date and demonstrate that substantial plant–substrate interactions were under way by Early Devonian time. The morphological relationships between stems, root-bearing axes and roots corroborate evidence that positive gravitropism and root identity were evolutionarily

  5. Arabidopsis mutants lacking asparaginases develop normally but exhibit enhanced root inhibition by exogenous asparagine.

    Science.gov (United States)

    Ivanov, Ana; Kameka, Alexander; Pajak, Agnieszka; Bruneau, Luanne; Beyaert, Ronald; Hernández-Sebastià, Cinta; Marsolais, Frédéric

    2012-06-01

    Asparaginase catalyzes the degradation of L-asparagine to L-aspartic acid and ammonia, and is implicated in the catabolism of transported asparagine in sink tissues of higher plants. The Arabidopsis genome includes two genes, ASPGA1 and ASPGB1, belonging to distinct asparaginase subfamilies. Conditions of severe nitrogen limitation resulted in a slight decrease in seed size in wild-type Arabidopsis. However, this response was not observed in a homozygous T-DNA insertion mutant where ASPG genes had been inactivated. Under nitrogen-sufficient conditions, the ASPG mutant had elevated levels of free asparagine in mature seed. This phenotype was observed exclusively under conditions of low illumination, when a low ratio of carbon to nitrogen was translocated to the seed. Mutants deficient in one or both asparaginases were more sensitive than wild-type to inhibition of primary root elongation and root hair emergence by L-asparagine as a single nitrogen source. This enhanced inhibition was associated with increased accumulation of asparagine in the root of the double aspga1-1/-b1-1 mutant. This indicates that inhibition of root growth is likely elicited by asparagine itself or an asparagine-derived metabolite, other than the products of asparaginase, aspartic acid or ammonia. During germination, a fusion between the ASPGA1 promoter and beta-glucuronidase was expressed in endosperm cells starting at the micropylar end. Expression was initially high throughout the root and hypocotyl, but became restricted to the root tip after three days, which may indicate a transition to nitrogen-heterotrophic growth.

  6. Abscisic acid is not necessary for gravitropism in primary roots of Zea mays

    Science.gov (United States)

    Moore, R.

    1990-01-01

    Primary roots of Zea mays L. cv. Tx 5855 treated with fluridone are strongly graviresponsive, but have undetectable levels of abscisic acid (ABA). Primary roots of the carotenoid-deficient w-3, vp-5, and vp-7 mutants of Z. mays are also graviresponsive despite having undetectable amounts of ABA. Graviresponsive roots of untreated and wild-type seedlings contain 286 to 317 ng ABA g-1 f. wt, respectively. These results indicate that ABA is not necessary for root gravicurvature.

  7. Antioxidant, antimicrobial and urease inhibiting activities of methanolic extracts from Cyphostemma digitatum stem and roots.

    Science.gov (United States)

    Khan, Rasool; Saif, Abdullah Qasem; Quradha, Mohammed Mansour; Ali, Jawad; Rauf, Abdur; Khan, Ajmal

    2016-01-01

    Cyphostemma digitatum stem and roots extracts were investigated for antioxidant, antimicrobial, urease inhibition potential and phytochemical analysis. Phytochemical screening of the roots and stem extract revealed the presence of secondary metabolites including flavonoids, alkaloids, coumarins, saponins, terpenoids, tannins, carbohydrates/reducing sugars and phenolic compounds. The methanolic extracts of the roots displayed highest antioxidant activity (93.518%) against DPPH while the crude methanolic extract of the stem showed highest antioxidant activity (66.163%) at 100 μg/mL concentration. The methanolic extracts of both stem and roots were moderately active or even found to be less active against the selected bacterial and fungal strains (Tables S2 and S3). The roots extract (methanol) showed significant urease enzyme inhibition activity (IC50 = 41.2 ± 0.66; 0.2 mg/mL) while the stem extract was found moderately active (IC50 = 401.1 ± 0.58; 0.2 mg/mL) against thiourea (IC50 = 21.011; 0.2 mg/mL).

  8. Trigoxazonane, a monosubstituted trioxazonane from Trigonella foenum-graecum root exudate, inhibits Orobanche crenata seed germination.

    Science.gov (United States)

    Evidente, Antonio; Fernández-Aparicio, Mónica; Andolfi, Anna; Rubiales, Diego; Motta, Andrea

    2007-10-01

    Orobanche crenata is a major threat to grain legume production. Fenugreek (Trigonella foenum-graecum) is an annual legume that has been shown to effectively reduce O. crenata infection when intercropped with grain legumes. In this paper, we point that this can be attributed to allelopathy, through inhibition of the germination of O. crenata by fenugreek root exudates. The main inhibitory metabolite was isolated and characterized. Allelopathy was demonstrated in different bioassays, by inhibition of O. crenata seeds germination both by growing fenugreek and pea plants together (intercropped), and by application of fenugreek root exudates. Fenugreek root exudates were extracted with organic solvent and fractionated giving several fractions, two of which showed moderate (27%) and strong (54%) inhibition of O. crenata seed germination, respectively. The most active metabolite is a new monosubstituted trioxazonane, characterized by spectroscopic methods as the 2-butyl-[1,4,7,2]trioxazonane and named trigoxazonane.

  9. Roles of abscisic acid and auxin in shoot-supplied ammonium inhibition of root system development

    OpenAIRE

    Li, Baohai; Li, Qing; Kronzucker, Herbert J; Shi, Weiming

    2011-01-01

    A plastic root system is a prerequisite for successful plant acclimation to variable environments. The normally functioning root system is the result of a complex interaction of root-borne signals and shoot-derived regulators. We recently demonstrated that AUX1, a well-studied component of auxin transport, mediates shoot-supplied ammonium (SSA) inhibition of lateral root (LR) formation in Arabidopsis. By contrast, the response did not involve ABA pathways, via which several other abiotic stre...

  10. Inhibition of white light of 86Rb+ absorption in the root apex of corn

    International Nuclear Information System (INIS)

    McKendree, W.L.; Smith, R.C.

    1990-01-01

    Measurements of cell lengths made at 0.5 millimeter intervals in median longitudinal sections of the primary roots of corn (Zea mays) were used to construct a growth curve. The region 1.5 to 4.0 millimeters from the apex contained the largest number of elongating cells. Absorption of 86 Rb + was measured using intact, dark-grown corn seedlings. Following uptake and exchange, the terminal 8.0 millimeters of each root was cut into four 2.0 millimeter segments. Maximum 86 Rb + uptake occurred in the region from 0.0 to 4.0 millimeter from the root tip. Washing the intact primary root in fresh 2.0 millimolar CaSO 4 for 2 hours prior to uptake augmented the rate of 86 Rb + uptake in all regions. Illumination with white light during washing caused a reduction of 86 Rb + uptake as compared with controls washing in darkness, and the region of greatest light response was the region of elongation. Removal of the coleoptile prior to washing did not prevent the light inhibition of subsequent 86 Rb + uptake. Removal of the root cap prior to washing in light partially reversed the light-induced inhibition of the washing response

  11. Actin is an essential component of plant gravitropic signaling pathways

    Science.gov (United States)

    Braun, Markus; Hauslage, Jens; Limbach, Christoph

    2003-08-01

    A role of the actin cytoskeleton in the different phases of gravitropism in higher plant organs seems obvious, but experimental evidence is still inconclusive and contradictory. In gravitropically tip-growing rhizoids and protonemata, however, it is well documented that actin is an essential component of the tip-growth machinery and is involved either in the cellular mechanisms that lead to gravity sensing and in the processes of the graviresponses that result in the reorientation of the growth direction. All these processes depend on a complexly organized and highly dynamic organization of actin filaments whose diverse functions are coordinated by numerous associated proteins. Actin filaments and myosins mediate the transport of secretory vehicles to the growing tip and precisely control the delivery of cell wall material. In addition, both cell types use a very efficient actomyosin-based system to control and correct the position of their statoliths and to direct sedimenting statoliths to confined graviperception sites at the plasma membrane. The studies presented in this paper provide evidence for the essential role of actin in plant gravity sensing and the gravitropic responses. A unique actin-organizing center exists in the tip of characean rhizoids and protonemata which is associated with and dynamically regulated by a specific set of actin-dynamizing proteins. It is concluded that this highly dynamic apical actin array is an essential prerequisite for gravity sensing and gravity-oriented tip growth.

  12. Genetic Analysis of Gravity Signal Transduction in Arabidopsis Roots

    Science.gov (United States)

    Masson, Patrick; Strohm, Allison; Barker, Richard; Su, Shih-Heng

    Like most other plant organs, roots use gravity as a directional guide for growth. Specialized cells within the columella region of the root cap (the statocytes) sense the direction of gravity through the sedimentation of starch-filled plastids (amyloplasts). Amyloplast movement and/or pressure on sensitive membranes triggers a gravity signal transduction pathway within these cells, which leads to a fast transcytotic relocalization of plasma-membrane associated auxin-efflux carrier proteins of the PIN family (PIN3 and PIN7) toward the bottom membrane. This leads to a polar transport of auxin toward the bottom flank of the cap. The resulting lateral auxin gradient is then transmitted toward the elongation zones where it triggers a curvature that ultimately leads to a restoration of vertical downward growth. Our laboratory is using strategies derived from genetics and systems biology to elucidate the molecular mechanisms that modulate gravity sensing and signal transduction in the columella cells of the root cap. Our previous research uncovered two J-domain-containing proteins, ARG1 and ARL2, as contributing to this process. Mutations in the corresponding paralogous genes led to alterations of root and hypocotyl gravitropism accompanied by an inability for the statocytes to develop a cytoplasmic alkalinization, relocalize PIN3, and transport auxin laterally, in response to gravistimulation. Both proteins are associated peripherally to membranes belonging to various compartments of the vesicular trafficking pathway, potentially modulating the trafficking of defined proteins between plasma membrane and endosomes. MAR1 and MAR2, on the other end, are distinct proteins of the plastidic outer envelope protein import TOC complex (the transmembrane channel TOC75 and the receptor TOC132, respectively). Mutations in the corresponding genes enhance the gravitropic defects of arg1. Using transformation-rescue experiments with truncated versions of TOC132 (MAR2), we have shown

  13. Mobile phone radiation inhibits Vigna radiata (mung bean) root growth by inducing oxidative stress

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Ved Parkash [Department of Environment and Vocational Studies, Panjab University, Chandigarh 160014 (India); Department of Zoology, Panjab University, Chandigarh 160014 (India); Singh, Harminder Pal, E-mail: hpsingh_01@yahoo.com [Department of Environment and Vocational Studies, Panjab University, Chandigarh 160014 (India); Kohli, Ravinder Kumar; Batish, Daizy Rani [Department of Botany, Panjab University, Chandigarh 160014 (India)

    2009-10-15

    During the last couple of decades, there has been a tremendous increase in the use of cell phones. It has significantly added to the rapidly increasing EMF smog, an unprecedented type of pollution consisting of radiation in the environment, thereby prompting the scientists to study the effects on humans. However, not many studies have been conducted to explore the effects of cell phone EMFr on growth and biochemical changes in plants. We investigated whether EMFr from cell phones inhibit growth of Vigna radiata (mung bean) through induction of conventional stress responses. Effects of cell phone EMFr (power density: 8.55 {mu}W cm{sup -2}; 900 MHz band width; for 1/2, 1, 2, and 4 h) were determined by measuring the generation of reactive oxygen species (ROS) in terms of malondialdehyde and hydrogen peroxide (H{sub 2}O{sub 2}) content, root oxidizability and changes in levels of antioxidant enzymes. Our results showed that cell phone EMFr significantly inhibited the germination (at {>=}2 h), and radicle and plumule growths ({>=}1 h) in mung bean in a time-dependent manner. Further, cell phone EMFr enhanced MDA content (indicating lipid peroxidation), and increased H{sub 2}O{sub 2} accumulation and root oxidizability in mung bean roots, thereby inducing oxidative stress and cellular damage. In response to EMFr, there was a significant upregulation in the activities of scavenging enzymes, such as superoxide dismutases, ascorbate peroxidases, guaiacol peroxidases, catalases and glutathione reductases, in mung bean roots. The study concluded that cell phone EMFr inhibit root growth of mung bean by inducing ROS-generated oxidative stress despite increased activities of antioxidant enzymes.

  14. Mobile phone radiation inhibits Vigna radiata (mung bean) root growth by inducing oxidative stress

    International Nuclear Information System (INIS)

    Sharma, Ved Parkash; Singh, Harminder Pal; Kohli, Ravinder Kumar; Batish, Daizy Rani

    2009-01-01

    During the last couple of decades, there has been a tremendous increase in the use of cell phones. It has significantly added to the rapidly increasing EMF smog, an unprecedented type of pollution consisting of radiation in the environment, thereby prompting the scientists to study the effects on humans. However, not many studies have been conducted to explore the effects of cell phone EMFr on growth and biochemical changes in plants. We investigated whether EMFr from cell phones inhibit growth of Vigna radiata (mung bean) through induction of conventional stress responses. Effects of cell phone EMFr (power density: 8.55 μW cm -2 ; 900 MHz band width; for 1/2, 1, 2, and 4 h) were determined by measuring the generation of reactive oxygen species (ROS) in terms of malondialdehyde and hydrogen peroxide (H 2 O 2 ) content, root oxidizability and changes in levels of antioxidant enzymes. Our results showed that cell phone EMFr significantly inhibited the germination (at ≥2 h), and radicle and plumule growths (≥1 h) in mung bean in a time-dependent manner. Further, cell phone EMFr enhanced MDA content (indicating lipid peroxidation), and increased H 2 O 2 accumulation and root oxidizability in mung bean roots, thereby inducing oxidative stress and cellular damage. In response to EMFr, there was a significant upregulation in the activities of scavenging enzymes, such as superoxide dismutases, ascorbate peroxidases, guaiacol peroxidases, catalases and glutathione reductases, in mung bean roots. The study concluded that cell phone EMFr inhibit root growth of mung bean by inducing ROS-generated oxidative stress despite increased activities of antioxidant enzymes.

  15. Gravity-dependent differentiation and root coils in Arabidopsis thaliana wild type and phospholipase-A-I knockdown mutant grown on the International Space Station.

    Science.gov (United States)

    Scherer, G F E; Pietrzyk, P

    2014-01-01

    Arabidopsis roots on 45° tilted agar in 1-g grow in wave-like figures. In addition to waves, formation of root coils is observed in several mutants compromised in gravitropism and/or auxin transport. The knockdown mutant ppla-I-1 of patatin-related phospholipase-A-I is delayed in root gravitropism and forms increased numbers of root coils. Three known factors contribute to waving: circumnutation, gravisensing and negative thigmotropism. In microgravity, deprivation of wild type (WT) and mutant roots of gravisensing and thigmotropism and circumnutation (known to slow down in microgravity, and could potentially lead to fewer waves or increased coiling in both WT and mutant). To resolve this, mutant ppla-I-1 and WT were grown in the BIOLAB facility in the International Space Station. In 1-g, roots of both types only showed waving. In the first experiment in microgravity, the mutant after 9 days formed far more coils than in 1-g but the WT also formed several coils. After 24 days in microgravity, in both types the coils were numerous with slightly more in the mutant. In the second experiment, after 9 days in microgravity only the mutant formed coils and the WT grew arcuated roots. Cell file rotation (CFR) on the mutant root surface in microgravity decreased in comparison to WT, and thus was not important for coiling. Several additional developmental responses (hypocotyl elongation, lateral root formation, cotyledon expansion) were found to be gravity-influenced. We tentatively discuss these in the context of disturbances in auxin transport, which are known to decrease through lack of gravity. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

  16. Water Deficit and Abscisic Acid Cause Differential Inhibition of Shoot versus Root Growth in Soybean Seedlings 1

    Science.gov (United States)

    Creelman, Robert A.; Mason, Hugh S.; Bensen, Robert J.; Boyer, John S.; Mullet, John E.

    1990-01-01

    Roots often continue to elongate while shoot growth is inhibited in plants subjected to low-water potentials. The cause of this differential response to water deficit was investigated. We examined hypocotyl and root growth, polysome status and mRNA populations, and abscisic acid (ABA) content in etiolated soybean (Glycine max [L.] Merr. cv Williams) seedlings whose growth was inhibited by transfer to low-water potential vermiculite or exogenous ABA. Both treatments affected growth and dry weight in a similar fashion. Maximum inhibition of hypocotyl growth occurred when internal ABA levels (modulated by ABA application) reached the endogenous level found in the elongating zone of seedlings grown in water-deficient vermiculite. Conversely, root growth was affected to only a slight extent in low-water potential seedlings and by most ABA treatments (in some, growth was promoted). In every seedling section examined, transfer of seedlings into low-water potential vermiculite caused ABA levels to increase approximately 5- to 10-fold over that found in well-watered seedlings. Changes in soluble sugar content, polysome status, and polysome mRNA translation products seen in low-water potential seedlings did not occur with ABA treatments sufficient to cause significant inhibition of hypocotyl elongation. These data suggest that both variation in endogenous ABA levels, and differing sensitivity to ABA in hypocotyls and roots can modulate root/shoot growth ratios. However, exogenous ABA did not induce changes in sugar accumulation, polysome status, and mRNA populations seen after transfer into low-water potential vermiculite. Images Figure 6 Figure 7 PMID:16667248

  17. Deep Roots? Behavioral Inhibition and Behavioral Activation System (BIS/BAS) Sensitivity and Entrepreneurship

    NARCIS (Netherlands)

    Lerner, Daniel; Hatak, Isabella; Rauch, Andreas

    2018-01-01

    A growing number of studies suggest a link between disinhibition and entrepreneurship. Separately, psychology literature has theorized and empirically shown that the roots of disinhibition can largely be traced to two psychophysiological systems – the behavioral inhibition system (BIS) and

  18. Towards systems biology of the gravity response of higher plants -multiscale analysis of Arabidopsis thaliana root growth

    Science.gov (United States)

    Palme, Klaus; Aubry, D.; Bensch, M.; Schmidt, T.; Ronneberger, O.; Neu, C.; Li, X.; Wang, H.; Santos, F.; Wang, B.; Paponov, I.; Ditengou, F. A.; Teale, W. T.; Volkmann, D.; Baluska, F.; Nonis, A.; Trevisan, S.; Ruperti, B.; Dovzhenko, A.

    Gravity plays a fundamental role in plant growth and development. Up to now, little is known about the molecular organisation of the signal transduction cascades and networks which co-ordinate gravity perception and response. By using an integrated systems biological approach, a systems analysis of gravity perception and the subsequent tightly-regulated growth response is planned in the model plant Arabidopsis thaliana. This approach will address questions such as: (i) what are the components of gravity signal transduction pathways? (ii) what are the dynamics of these components? (iii) what is their spatio-temporal regulation in different tis-sues? Using Arabidopsis thaliana as a model-we use root growth to obtain insights in the gravity response. New techniques enable identification of the individual genes affected by grav-ity and further integration of transcriptomics and proteomics data into interaction networks and cell communication events that operate during gravitropic curvature. Using systematic multiscale analysis we have identified regulatory networks consisting of transcription factors, the protein degradation machinery, vesicle trafficking and cellular signalling during the gravire-sponse. We developed approach allowing to incorporate key features of the root system across all relevant spatial and temporal scales to describe gene-expression patterns and correlate them with individual gene and protein functions. Combination of high-resolution microscopy and novel computational tools resulted in development of the root 3D model in which quantitative descriptions of cellular network properties and of multicellular interactions important in root growth and gravitropism can be integrated for the first time.

  19. The Arabidopsis LAZY1 Family Plays a Key Role in Gravity Signaling within Statocytes and in Branch Angle Control of Roots and Shoots.

    Science.gov (United States)

    Taniguchi, Masatoshi; Furutani, Masahiko; Nishimura, Takeshi; Nakamura, Moritaka; Fushita, Toyohito; Iijima, Kohta; Baba, Kenichiro; Tanaka, Hirokazu; Toyota, Masatsugu; Tasaka, Masao; Morita, Miyo Terao

    2017-08-01

    During gravitropism, the directional signal of gravity is perceived by gravity-sensing cells called statocytes, leading to asymmetric distribution of auxin in the responding organs. To identify the genes involved in gravity signaling in statocytes, we performed transcriptome analyses of statocyte-deficient Arabidopsis thaliana mutants and found two candidates from the LAZY1 family, AtLAZY1 / LAZY1-LIKE1 ( LZY1 ) and AtDRO3 / AtNGR1 / LZY2 We showed that LZY1 , LZY2 , and a paralog AtDRO1/AtNGR2/LZY3 are redundantly involved in gravitropism of the inflorescence stem, hypocotyl, and root. Mutations of LZY genes affected early processes in gravity signal transduction without affecting amyloplast sedimentation. Statocyte-specific expression of LZY genes rescued the mutant phenotype, suggesting that LZY genes mediate gravity signaling in statocytes downstream of amyloplast displacement, leading to the generation of asymmetric auxin distribution in gravity-responding organs. We also found that lzy mutations reversed the growth angle of lateral branches and roots. Moreover, expression of the conserved C-terminal region of LZY proteins also reversed the growth direction of primary roots in the lzy mutant background. In lateral root tips of lzy multiple mutants, asymmetric distribution of PIN3 and auxin response were reversed, suggesting that LZY genes regulate the direction of polar auxin transport in response to gravity through the control of asymmetric PIN3 expression in the root cap columella. © 2017 American Society of Plant Biologists. All rights reserved.

  20. Inhibition of primary roots and stimulation of lateral root development in Arabidopsis thaliana by the rhizobacterium Serratia marcescens 90-166 is through both auxin-dependent and -independent signaling pathways.

    Science.gov (United States)

    Shi, Chun-Lin; Park, Hyo-Bee; Lee, Jong Suk; Ryu, Sangryeol; Ryu, Choong-Min

    2010-03-01

    The rhizobacterium Serratia marcescens strain 90-166 was previously reported to promote plant growth and induce resistance in Arabidopsis thaliana. In this study, the influence of strain 90-166 on root development was studied in vitro. We observed inhibition of primary root elongation, enhanced lateral root emergence, and early emergence of second order lateral roots after inoculation with strain 90-166 at a certain distance from the root. Using the DR5::GUS transgenic A. thaliana plant and an auxin transport inhibitor, N-1-naphthylphthalamic acid, the altered root development was still elicited by strain 90-166, indicating that this was not a result of changes in plant auxin levels. Intriguingly, indole-3-acetic acid, a major auxin chemical, was only identified just above the detection limit in liquid culture of strain 90-166 using liquid chromatography-mass spectrometry. Focusing on bacterial determinants of the root alterations, we found that primary root elongation was inhibited in seedlings treated with cell supernatant (secreted compounds), while lateral root formation was induced in seedlings treated with lysate supernatant (intracellular compounds). Further study revealed that the alteration of root development elicited by strain 90-166 involved the jasmonate, ethylene, and salicylic acid signaling pathways. Collectively, our results suggest that strain 90-166 can contribute to plant root development via multiple signaling pathways.

  1. The root barks of Morus alba and the flavonoid constituents inhibit airway inflammation.

    Science.gov (United States)

    Lim, Hun Jai; Jin, Hong-Guang; Woo, Eun-Rhan; Lee, Sang Kook; Kim, Hyun Pyo

    2013-08-26

    The root barks of Morus alba have been used in traditional medicine as an anti-inflammatory drug, especially for treating lung inflammatory disorders. To find new alternative agents against airway inflammation and to establish the scientific rationale of the herbal medicine in clinical use, the root barks of Morus alba and its flavonoid constituents were examined for the first time for their pharmacological activity against lung inflammation. For in vivo evaluation, an animal model of lipopolysaccharide-induced airway inflammation in mice was used. An inhibitory action against the production of proinflammatory molecules in lung epithelial cells and lung macrophages was examined. Against lipopolysaccharide-induced airway inflammation, the ethanol extract of the root barks of Morus alba clearly inhibited bronchitis-like symptoms, as determined by TNF-α production, inflammatory cells infiltration and histological observation at 200-400mg/kg/day by oral administration. In addition, Morus alba and their major flavonoid constituents including kuwanone E, kuwanone G and norartocarpanone significantly inhibited IL-6 production in lung epithelial cells (A549) and NO production in lung macrophages (MH-S). Taken together, it is concluded that Morus alba and the major prenylated flavonoid constituents have a potential for new agents to control lung inflammation including bronchitis. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  2. Inhibition of Cariogenic Plaque Formation on Root Surface with Polydopamine-Induced-Polyethylene Glycol Coating

    Directory of Open Access Journals (Sweden)

    May Lei Mei

    2016-05-01

    Full Text Available Root caries prevention has been a challenge for clinicians due to its special anatomical location, which favors the accumulation of dental plaque. Researchers are looking for anti-biofouling material to inhibit bacterial growth on exposed root surfaces. This study aimed to develop polydopamine-induced-polyethylene glycol (PEG and to study its anti-biofouling effect against a multi-species cariogenic biofilm on the root dentine surface. Hydroxyapatite disks and human dentine blocks were divided into four groups for experiments. They received polydopamine-induced-PEG, PEG, polydopamine, or water application. Contact angle, quartz crystal microbalance, and Fourier transform infrared spectroscopy were used to study the wetting property, surface affinity, and an infrared spectrum; the results indicated that PEG was induced by polydopamine onto a hydroxyapatite disk. Salivary mucin absorption on hydroxyapatite disks with polydopamine-induced-PEG was confirmed using spectrophotometry. The growth of a multi-species cariogenic biofilm on dentine blocks with polydopamine-induced-PEG was assessed and monitored by colony-forming units, confocal laser scanning microscopy, and scanning electron microscopy. The results showed that dentine with polydopamine-induced-PEG had fewer bacteria than other groups. In conclusion, a novel polydopamine-induced-PEG coating was developed. Its anti-biofouling effect inhibited salivary mucin absorption and cariogenic biofilm formation on dentine surface and thus may be used for the prevention of root dentine caries.

  3. Effect of CO2 laser on root caries inhibition around composite restorations: an in vitro study.

    Science.gov (United States)

    de Melo, Jociana Bandeira; Hanashiro, Fernando Seishim; Steagall, Washington; Turbino, Miriam Lacalle; Nobre-dos-Santos, Marinês; Youssef, Michel Nicolau; de Souza-Zaroni, Wanessa Christine

    2014-03-01

    The aim of the present study was to investigate the in vitro effect of CO2 laser on the inhibition of root surface demineralization around composite resin restorations. For this purpose, 30 blocks obtained from human molar roots were divided into three groups: group 1 (negative control), cavity prepared with cylindrical diamond bur + acid etching + adhesive + composite resin restoration; group 2, cavity prepared with cylindrical diamond bur + CO2 laser (5.0 J/cm(2)) + acid etching + adhesive + composite resin; and group 3, cavity prepared with cylindrical diamond bur + CO2 laser (6.0 J/cm(2)) + acid etching + adhesive + composite resin. After this procedure, the blocks were submitted to thermal and pH cycling. Root surface demineralization around the restorations was measured by microhardness analysis. The hardness results of the longitudinally sectioned root surface were converted into percentage of mineral volume, which was used to calculate the mineral loss delta Z (ΔZ). The percentage of mineral volume, ΔZ, and the percentage of demineralization inhibition of the groups were statistically analyzed by using analysis of variance and Tukey-Kramer test. The percentage of mineral volume was higher in the irradiated groups up to 80 μm deep. The ΔZ was significantly lower in the irradiated groups than in the control group. The percentage of reduction in demineralization ranged from 19.73 to 29.21 in position 1 (50 μm), and from 24.76 to 26.73 in position 2 (100 μm), when using 6 and 5 J/cm(2), respectively. The CO2 laser was effective in inhibiting root demineralization around composite resin restorations.

  4. Transcriptional and Hormonal Regulation of Gravitropism of Woody Stems in Populus

    Science.gov (United States)

    Suzanne Gerttula; Matthew S. Zinkgraf; Gloria K. Muday; Daniel R. Lewis; Farid M. Ibatullin; Harry Brumer; Foster Hart; Shawn D. Mansfield; Vladimir Filkov; Andrew Groover

    2015-01-01

    Angiosperm trees reorient their woody stems by asymmetrically producing a specialized xylem tissue, tension wood, which exerts a strong contractile force resulting in negative gravitropism of the stem. Here, we show, in Populus trees, that initial gravity perception and response occurs in specialized cells through sedimentation of starch-filled...

  5. Profiling Gene Expression in Germinating Brassica Roots.

    Science.gov (United States)

    Park, Myoung Ryoul; Wang, Yi-Hong; Hasenstein, Karl H

    2014-01-01

    Based on previously developed solid-phase gene extraction (SPGE) we examined the mRNA profile in primary roots of Brassica rapa seedlings for highly expressed genes like ACT7 (actin7), TUB (tubulin1), UBQ (ubiquitin), and low expressed GLK (glucokinase) during the first day post-germination. The assessment was based on the mRNA load of the SPGE probe of about 2.1 ng. The number of copies of the investigated genes changed spatially along the length of primary roots. The expression level of all genes differed significantly at each sample position. Among the examined genes ACT7 expression was most even along the root. UBQ was highest at the tip and root-shoot junction (RS). TUB and GLK showed a basipetal gradient. The temporal expression of UBQ was highest in the MZ 9 h after primary root emergence and higher than at any other sample position. Expressions of GLK in EZ and RS increased gradually over time. SPGE extraction is the result of oligo-dT and oligo-dA hybridization and the results illustrate that SPGE can be used for gene expression profiling at high spatial and temporal resolution. SPGE needles can be used within two weeks when stored at 4 °C. Our data indicate that gene expression studies that are based on the entire root miss important differences in gene expression that SPGE is able to resolve for example growth adjustments during gravitropism.

  6. ARG1 and ARL2 contribute to gravity signal transduction in the statocytes of Arabidopsis thaliana roots and hypocotyls

    Science.gov (United States)

    Masson, Patrick; Harrison, Benjamin; Stanga, John; Otegui, Marisa; Sedbrook, John

    Gravity is an important cue that plant organs use to guide their growth. Each organ is characterized by a defined gravity set point angle that dictates its optimal orientation within the gravity field. Specialized cells, named statocytes, enable this directional growth response by perceiving gravity via the sedimentation of, and/or tension/pressure exerted by, starch-filled plastids within their cytoplasm. Located in the columella region of the cap in roots and in the endodermis of hypocotyls and stems, these cells modulate the lateral transport of auxin across the corresponding organ in a gravistimulus-dependent manner. Upon plant reorientation within the gravity field, a gravity signal transduction pathway is activated within those cells, which in roots leads to a relocalization of the PIN3 auxin efflux carrier toward the lower membrane and an alkalinization of the cytoplasm. In turn, these events appear to promote a lateral transport of auxin toward the bottom side of the stimulated organ, which promotes a curvature. We previously uncovered ARG1 and ARL2 as essential contributors to these cellular processes. Mutations in these genes result in altered root and hypocotyl gravitropism. In roots, this abnormal growth behavior is associated with a lack of PIN3 relocalization within the statocytes and an absence of preferential downward auxin transport upon gravistimulation. These two genes encode paralogous J-domain proteins that are associated with the plasma membrane and other membranes of the vesicular trafficking pathway, and appear to modulate protein trafficking within the statocytes. An analysis of the root gravitropic phenotypes associated with different double mutant configurations affecting ARG1, ARL2 and PIN3 suggest that all three proteins function in a common gravity-signaling pathway. Surprisingly, when a mutation that affects starch biosynthesis (pgm) is introgressed into an arg1-2 mutant, the gravitropic defects are dramatically enhanced relative to

  7. Methyl Protodioscin from the Roots of Asparagus cochinchinensis Attenuates Airway Inflammation by Inhibiting Cytokine Production

    Directory of Open Access Journals (Sweden)

    Ju Hee Lee

    2015-01-01

    Full Text Available The present study was designed to find pharmacologically active compound against airway inflammation from the roots of Asparagus cochinchinensis. The 70% ethanol extract of the roots of A. cochinchinensis (ACE was found to inhibit IL-6 production from IL-1β-treated lung epithelial cells (A549 and the major constituent, methyl protodioscin (MP, also strongly inhibited the production of IL-6, IL-8, and tumor necrosis factor- (TNF- α from A549 cells at 10–100 μM. This downregulating effect of proinflammatory cytokine production was found to be mediated, at least in part, via inhibition of c-Jun N-terminal kinase (JNK and c-Jun activation pathway. When examined on an in vivo model of airway inflammation in mice, lipopolysaccharide- (LPS- induced acute lung injury, ACE, and MP significantly inhibited cell infiltration in the bronchoalveolar lavage fluid by the oral treatment at doses of 100–400 mg/kg and 30–60 mg/kg, respectively. MP also inhibited the production of proinflammatory cytokines such as IL-6, TNF-α, and IL-1β in lung tissue. All of these findings provide scientific evidence supporting the role of A. cochinchinensis as a herbal remedy in treating airway inflammation and also suggest a therapeutic value of MP on airway inflammatory disorders.

  8. Selenium hyperaccumulation by Astragalus (Fabaceae) does not inhibit root nodule symbiosis.

    Science.gov (United States)

    Alford, Elan R; Pilon-Smits, Elizabeth A H; Fakra, Sirine C; Paschke, Mark W

    2012-12-01

    A survey of the root-nodule symbiosis in Astragalus and its interaction with selenium (Se) has not been conducted before. Such studies can provide insight into how edaphic conditions modify symbiotic interactions and influence partner coevolution. In this paper plant-organ Se concentration ([Se]) was investigated to assess potential Se exposure to endophytes. • Selenium distribution and molecular speciation of root nodules from Se-hyperaccumulators Astragalus bisulcatus, A. praelongus, and A. racemosus was determined by Se K-edge x-ray absorption spectroscopy. A series of greenhouse experiments were conducted to characterize the response of root-nodule symbiosis in Se-hyperaccumulators and nonhyperaccumulators. • Nodules in three Se-hyperaccumulators (Astragalus crotalariae, A. praelongus, and A. preussii) are reported for the first time. Leaves, flowers, and fruits from Se-hyperaccumulators were routinely above the hyperaccumulator threshold (1,000 µg Se g(-1) DW), but root samples rarely contained that amount, and nodules never exceeded 110 µg Se g(-1) DW. Nodules from A. bisulcatus, A. praelongus, and A. racemosus had Se throughout, with a majority stored in C-Se-C form. Finally, an evaluation of nodulation in Se-hyperaccumulators and nonhyperaccumulators indicated that there was no nodulation inhibition because of plant Se tolerance. Rather, we found that in Se-hyperaccumulators higher levels of Se treatment (up to 100 µM Se) corresponded with higher nodule counts, indicating a potential role for dinitrogen fixation in Se-hyperaccumulation. The effect was not found in nonhyperaccumulators. • As the evolution of Se hyperaccumulation in Astragalus developed, root-nodule symbiosis may have played an integral role.

  9. The inhibiting effects of Urtica dioica root extracts on experimentally induced prostatic hyperplasia in the mouse.

    Science.gov (United States)

    Lichius, J J; Muth, C

    1997-08-01

    Extracts of stinging nettle roots (Urtica dioica L. Urticaceae) are used in the treatment of benign prostatic hyperplasia (BPH). We established a BPH-model by directly implanting an urogenital sinus (UGS) into the ventral prostate gland of an adult mouse. Five differently prepared stinging nettle root extracts were tested in this model. The 20% methanolic extract was the most effective with a 51.4% inhibition of induced growth.

  10. The ARG1-LIKE2 gene of Arabidopsis functions in a gravity signal transduction pathway that is genetically distinct from the PGM pathway

    Science.gov (United States)

    Guan, Changhui; Rosen, Elizabeth S.; Boonsirichai, Kanokporn; Poff, Kenneth L.; Masson, Patrick H.

    2003-01-01

    The arl2 mutants of Arabidopsis display altered root and hypocotyl gravitropism, whereas their inflorescence stems are fully gravitropic. Interestingly, mutant roots respond like the wild type to phytohormones and an inhibitor of polar auxin transport. Also, their cap columella cells accumulate starch similarly to wild-type cells, and mutant hypocotyls display strong phototropic responses to lateral light stimulation. The ARL2 gene encodes a DnaJ-like protein similar to ARG1, another protein previously implicated in gravity signal transduction in Arabidopsis seedlings. ARL2 is expressed at low levels in all organs of seedlings and plants. arl2-1 arg1-2 double mutant roots display kinetics of gravitropism similar to those of single mutants. However, double mutants carrying both arl2-1 and pgm-1 (a mutation in the starch-biosynthetic gene PHOSPHOGLUCOMUTASE) at the homozygous state display a more pronounced root gravitropic defect than the single mutants. On the other hand, seedlings with a null mutation in ARL1, a paralog of ARG1 and ARL2, behave similarly to the wild type in gravitropism and other related assays. Taken together, the results suggest that ARG1 and ARL2 function in the same gravity signal transduction pathway in the hypocotyl and root of Arabidopsis seedlings, distinct from the pathway involving PGM.

  11. Root graviresponsiveness and columella cell structure in carotenoid-deficient seedlings of Zea mays

    Science.gov (United States)

    Moore, R.; McClelen, C. E.

    1985-01-01

    Root graviresponsiveness in normal and carotenoid-deficient mutant seedlings of Zea mays was not significantly different. Columella cells in roots of mutant seedlings were characterized by fewer, smaller, and a reduced relative volume of plastids as compared to columella cells of normal seedlings. Plastids in columella cells of mutant seedlings possessed reduced amounts of starch. Although approximately 10 per cent of the columella cells in mutant seedlings lacked starch, their plastids were located at the bottom of the cell. These results suggest that (i) carotenoids are not necessary for root gravitropism, (ii) graviresponsiveness is not necessarily proportional to the size, number, or relative volume of plastids in columella cells, and (iii) sedimentation of plastids in columella cells may not result directly from their increased density due to starch content. Plastids in columella cells of normal and mutant seedlings were associated with bands of microtubule-like structures, suggesting that these structures may be involved in 'positioning' plastids in the cell.

  12. Light and decapitation effects on in vitro rooting in maize root segments.

    Science.gov (United States)

    Golaz, F W; Pilet, P E

    1985-10-01

    The effects of white light and decapitation on the initiation and subsequent emergence and elongation of lateral roots of apical maize (Zea mays L. cv LG 11) root segments have been examined. The formation of lateral root primordium was inhibited by the white light. This inhibition did not depend upon the presence of the primary root tip. However, root decapitation induced a shift of the site of appearance of the most apical primordium towards the root apex, and a strong disturbance of the distribution pattern of primordium volumes along the root axis. White light had a significant effect neither on the distribution pattern of primordium volumes, nor on the period of primordium development (time interval required for the smallest detectable primordia to grow out as secondary roots). Thus, considering the rooting initiation and emergence, the light effect was restricted to the initiation phase only. Moreover, white light reduced lateral root elongation as well as primary root growth.

  13. High-resolution mapping and genetic characterization of the Lazy-2 gravitropic mutant of tomato

    Science.gov (United States)

    Behringer, F. J.; Lomax, T. L.

    1999-01-01

    Mutation of the Lazy-2 (Lz-2) gene in tomato (Lycopersicon esculentum mill.) produces a phytochrome-dependent reversal of shoot gravitropism, providing a unique genetic resource for investigating how signals from light modulate gravitropism. We mapped the Lz-2 gene using RFLPs and a PCR-based technique to assess the feasibility of positional cloning. Analysis of a 1338 plant backcross population between L. esculentum and L. pennellii placed Lz-2 within a 1.2 cM interval on chromosome 5, 0.4 cM from TG504-CT201A interval. The inabililty to resolve these markers indicates that Lz-2 resides in a centromeric region in which recombination is highly suppressed. Lazy-2 is tightly linked to but does not encode the gene for ACC4, an enzyme involved in ethylene biosynthesis. We also observed that Lz-2 is partially dominant under certain conditions and stages of development.

  14. An Arabidopsis E3 Ligase, SHOOT GRAVITROPISM9, Modulates the Interaction between Statoliths and F-Actin in Gravity Sensing[W][OA

    Science.gov (United States)

    Nakamura, Moritaka; Toyota, Masatsugu; Tasaka, Masao; Morita, Miyo Terao

    2011-01-01

    Higher plants use the sedimentation of amyloplasts in statocytes as statolith to sense the direction of gravity during gravitropism. In Arabidopsis thaliana inflorescence stem statocyte, amyloplasts are in complex movement; some show jumping-like saltatory movement and some tend to sediment toward the gravity direction. Here, we report that a RING-type E3 ligase SHOOT GRAVITROPISM9 (SGR9) localized to amyloplasts modulates amyloplast dynamics. In the sgr9 mutant, which exhibits reduced gravitropism, amyloplasts did not sediment but exhibited increased saltatory movement. Amyloplasts sometimes formed a cluster that is abnormally entangled with actin filaments (AFs) in sgr9. By contrast, in the fiz1 mutant, an ACT8 semidominant mutant that induces fragmentation of AFs, amyloplasts, lost saltatory movement and sedimented with nearly statically. Both treatment with Latrunculin B, an inhibitor of AF polymerization, and the fiz1 mutation rescued the gravitropic defect of sgr9. In addition, fiz1 decreased saltatory movement and induced amyloplast sedimentation even in sgr9. Our results suggest that amyloplasts are in equilibrium between sedimentation and saltatory movement in wild-type endodermal cells. Furthermore, this equilibrium is the result of the interaction between amyloplasts and AFs modulated by the SGR9. SGR9 may promote detachment of amyloplasts from AFs, allowing the amyloplasts to sediment in the AFs-dependent equilibrium of amyloplast dynamics. PMID:21602290

  15. Gibberellin Is Involved in Inhibition of Cucumber Growth and Nitrogen Uptake at Suboptimal Root-Zone Temperatures.

    Directory of Open Access Journals (Sweden)

    Longqiang Bai

    Full Text Available Suboptimal temperature stress often causes heavy yield losses of vegetables by suppressing plant growth during winter and early spring. Gibberellin acid (GA has been reported to be involved in plant growth and acquisition of mineral nutrients. However, no studies have evaluated the role of GA in the regulation of growth and nutrient acquisition by vegetables under conditions of suboptimal temperatures in greenhouse. Here, we investigated the roles of GA in the regulation of growth and nitrate acquisition of cucumber (Cucumis sativus L. plants under conditions of short-term suboptimal root-zone temperatures (Tr. Exposure of cucumber seedlings to a Tr of 16°C led to a significant reduction in root growth, and this inhibitory effect was reversed by exogenous application of GA. Expression patterns of several genes encoding key enzymes in GA metabolism were altered by suboptimal Tr treatment, and endogenous GA concentrations in cucumber roots were significantly reduced by exposure of cucumber plants to 16°C Tr, suggesting that inhibition of root growth by suboptimal Tr may result from disruption of endogenous GA homeostasis. To further explore the mechanism underlying the GA-dependent cucumber growth under suboptimal Tr, we studied the effect of suboptimal Tr and GA on nitrate uptake, and found that exposure of cucumber seedlings to 16°C Tr led to a significant reduction in nitrate uptake rate, and exogenous application GA can alleviate the down-regulation by up regulating the expression of genes associated with nitrate uptake. Finally, we demonstrated that N accumulation in cucumber seedlings under suboptimal Tr conditions was improved by exogenous application of GA due probably to both enhanced root growth and nitrate absorption activity. These results indicate that a reduction in endogenous GA concentrations in roots due to down-regulation of GA biosynthesis at transcriptional level may be a key event to underpin the suboptimal Tr

  16. Characterization of root agravitropism induced by genetic, chemical, and developmental constraints

    International Nuclear Information System (INIS)

    Moore, R.; Fondren, W.M.; Marcum, H.

    1987-01-01

    The patterns and rates of organelle redistribution in columella (i.e., putative statocyte) cells of agravitropic agt mutants of Zea mays are not significantly different from those of columella cells in graviresponsive roots. Graviresponsive roots of Z. mays are characterized by a strongly polar movement of 45 Ca 2+ across the root tip from the upper to the lower side. Horizontally-oriented roots of agt mutants exhibit only a minimal polar transport of 45 Ca 2+ . Exogenously-induced asymmetries of Ca result in curvature of agt roots toward the Ca source. A similar curvature can be induced by a Ca asymmetry in normally nongraviresponsive (i.e., lateral) roots of Phaseolus vulgaris. Similarly, root curvature can be induced by placing the roots perpendicular to an electric field. This electrotropism increase with (1) currents between 8-35 mA, and (2) time between 1-9 hr when the current is constant. Electrotropism is reduced significantly by treating roots with triiodobenzoic acid (TIBA), an inhibitor of auxin transport. These results suggest that (1) if graviperception occurs via the sedimentation of amyloplasts in columella cells, then nongraviresponsive roots apparently sense gravity as do graviresponsive roots, (2) exogenously induced asymmetries of a gravitropic effector (i.e., Ca) can induce curvature of normally nongraviresponsive roots, (3) the gravity-induced downward movement of exogenously-applied 45 Ca 2+ across tips of graviresponsive roots does not occur in nongraviresponsive roots, (4) placing roots in an electrical field (i.e., one favoring the movement of ions such as Ca 2+ ) induces root curvature and (5) electrically-induced curvature is apparently dependent on auxin transport. These result are discussed relative to a model to account for the lack of graviresponsiveness by these roots

  17. Sprout inhibition in roots, tubers and bulbs; Inhibicion de brotes en raices, tuberculos y bulbos

    Energy Technology Data Exchange (ETDEWEB)

    Luna C, P.C

    1992-05-15

    The treatment with ionizing radiations to low dose impedes that appear sprouts in the tubers (potatoes); bulbs (onion and garlic) and in roots like the ginger and the yucca. The purpose is to inhibit the germination during the process of manipulation and storage, and this way to avoid the lost ones post crop of these products. The radiation dose required to inhibit the germination goes to depend of: the development conditions, the differences of variety, of the storage state of the bulbs and the conditions of cured and storage. (Author)

  18. Molecular mechanisms of root gravity sensing and signal transduction.

    Science.gov (United States)

    Strohm, Allison K; Baldwin, Katherine L; Masson, Patrick H

    2012-01-01

    Plants use gravity as a guide to direct their roots down into the soil to anchor themselves and to find resources needed for growth and development. In higher plants, the columella cells of the root tip form the primary site of gravity sensing, and in these cells the sedimentation of dense, starch-filled plastids (amyloplasts) triggers gravity signal transduction. This generates an auxin gradient across the root cap that is transmitted to the elongation zone where it promotes differential cell elongation, allowing the root to direct itself downward. It is still not well understood how amyloplast sedimentation leads to auxin redistribution. Models have been proposed to explain how mechanosensitive ion channels or ligand-receptor interactions could connect these events. Although their roles are still unclear, possible second messengers in this process include protons, Ca(2+), and inositol 1,4,5-triphosphate. Upon gravistimulation, the auxin efflux facilitators PIN3 and PIN7 relocalize to the lower side of the columella cells and mediate auxin redistribution. However, evidence for an auxin-independent secondary mechanism of gravity sensing and signal transduction suggests that this physiological process is quite complex. Furthermore, plants must integrate a variety of environmental cues, resulting in multifaceted relationships between gravitropism and other directional growth responses such as hydro-, photo-, and thigmotropism. Copyright © 2011 Wiley Periodicals, Inc.

  19. Adrenergic receptors inhibit TRPV1 activity in the dorsal root ganglion neurons of rats.

    Science.gov (United States)

    Matsushita, Yumi; Manabe, Miki; Kitamura, Naoki; Shibuya, Izumi

    2018-01-01

    Transient receptor potential vanilloid type 1 (TRPV1) is a polymodal receptor channel that responds to multiple types of stimuli, such as heat, acid, mechanical pressure and some vanilloids. Capsaicin is the most commonly used vanilloid to stimulate TRPV1. TRPV1 channels are expressed in dorsal root ganglion neurons that extend to Aδ- and C-fibers and have a role in the transduction of noxious inputs to the skin into the electrical signals of the sensory nerve. Although noradrenergic nervous systems, including the descending antinociceptive system and the sympathetic nervous system, are known to modulate pain sensation, the functional association between TRPV1 and noradrenaline in primary sensory neurons has rarely been examined. In the present study, we examined the effects of noradrenaline on capsaicin-evoked currents in cultured dorsal root ganglion neurons of the rat by the whole-cell voltage clamp method. Noradrenaline at concentrations higher than 0.1 pM significantly reduced the amplitudes of the inward capsaicin currents recorded at -60 mV holding potential. This inhibitory action was reversed by either yohimbine (an α2 antagonist, 10 nM) or propranolol (a β antagonist, 10 nM). The α2 agonists, clonidine (1 pM) and dexmedetomidine (1 pM) inhibited capsaicin currents, and yohimbine (1 nM) reversed the effects of clonidine. The inhibitory action of noradrenaline was not seen in the neurons pretreated with pertussis toxin (100 μg/ml for 24 h) and the neurons dialyzed intracellularly with guanosine 5'- [β-thio] diphosphate (GDPβS, 200 μM), the catalytic subunit of protein kinase A (250 U/ml) or okadaic acid (1 μM). These results suggest that noradrenaline directly acts on dorsal root ganglion neurons to inhibit the activity of TRPV1 depending on the activation of α2-adrenoceptors followed by the inhibition of the adenylate cyclase/cAMP/protein kinase A pathway.

  20. Ethylene-Induced Inhibition of Root Growth Requires Abscisic Acid Function in Rice (Oryza sativa L.) Seedlings

    Science.gov (United States)

    He, Si-Jie; Lu, Xiang; Zhang, Wan-Ke; Lu, Tie-Gang; Chen, Shou-Yi; Zhang, Jin-Song

    2014-01-01

    Ethylene and abscisic acid (ABA) have a complicated interplay in many developmental processes. Their interaction in rice is largely unclear. Here, we characterized a rice ethylene-response mutant mhz4, which exhibited reduced ethylene-response in roots but enhanced ethylene-response in coleoptiles of etiolated seedlings. MHZ4 was identified through map-based cloning and encoded a chloroplast-localized membrane protein homologous to Arabidopsis thaliana (Arabidopsis) ABA4, which is responsible for a branch of ABA biosynthesis. MHZ4 mutation reduced ABA level, but promoted ethylene production. Ethylene induced MHZ4 expression and promoted ABA accumulation in roots. MHZ4 overexpression resulted in enhanced and reduced ethylene response in roots and coleoptiles, respectively. In root, MHZ4-dependent ABA pathway acts at or downstream of ethylene receptors and positively regulates root ethylene response. This ethylene-ABA interaction mode is different from that reported in Arabidopsis, where ethylene-mediated root inhibition is independent of ABA function. In coleoptile, MHZ4-dependent ABA pathway acts at or upstream of OsEIN2 to negatively regulate coleoptile ethylene response, possibly by affecting OsEIN2 expression. At mature stage, mhz4 mutation affects branching and adventitious root formation on stem nodes of higher positions, as well as yield-related traits. Together, our findings reveal a novel mode of interplay between ethylene and ABA in control of rice growth and development. PMID:25330236

  1. Water Deficit and Abscisic Acid Cause Differential Inhibition of Shoot versus Root Growth in Soybean Seedlings : Analysis of Growth, Sugar Accumulation, and Gene Expression.

    Science.gov (United States)

    Creelman, R A; Mason, H S; Bensen, R J; Boyer, J S; Mullet, J E

    1990-01-01

    Roots often continue to elongate while shoot growth is inhibited in plants subjected to low-water potentials. The cause of this differential response to water deficit was investigated. We examined hypocotyl and root growth, polysome status and mRNA populations, and abscisic acid (ABA) content in etiolated soybean (Glycine max [L.] Merr. cv Williams) seedlings whose growth was inhibited by transfer to low-water potential vermiculite or exogenous ABA. Both treatments affected growth and dry weight in a similar fashion. Maximum inhibition of hypocotyl growth occurred when internal ABA levels (modulated by ABA application) reached the endogenous level found in the elongating zone of seedlings grown in water-deficient vermiculite. Conversely, root growth was affected to only a slight extent in low-water potential seedlings and by most ABA treatments (in some, growth was promoted). In every seedling section examined, transfer of seedlings into low-water potential vermiculite caused ABA levels to increase approximately 5- to 10-fold over that found in well-watered seedlings. Changes in soluble sugar content, polysome status, and polysome mRNA translation products seen in low-water potential seedlings did not occur with ABA treatments sufficient to cause significant inhibition of hypocotyl elongation. These data suggest that both variation in endogenous ABA levels, and differing sensitivity to ABA in hypocotyls and roots can modulate root/shoot growth ratios. However, exogenous ABA did not induce changes in sugar accumulation, polysome status, and mRNA populations seen after transfer into low-water potential vermiculite.

  2. Effects of cations on hormone transport in primary roots of Zea mays

    Science.gov (United States)

    Hasenstein, K. H.; Evans, M. L.

    1988-01-01

    We examined the influence of aluminum and calcium (and certain other cations) on hormone transport in corn roots. When aluminum was applied unilaterally to the caps of 15 mm apical root sections the roots curved strongly away from the aluminum. When aluminum was applied unilaterally to the cap and 3H-indole-3-acetic acid was applied to the basal cut surface twice as much radioactivity (assumed to be IAA) accumulated on the concave side of the curved root as on the convex side. Auxin transport in the apical region of intact roots was preferentially basipetal, with a polarity (basipetal transport divided by acropetal transport) of 6.3. In decapped 5 mm apical root segments, auxin transport was acropetally polar (polarity = 0.63). Application of aluminum to the root cap strongly promoted acropetal transport of auxin reducing polarity from 6.3 to 2.1. Application of calcium to the root cap enhanced basipetal movement of auxin, increasing polarity from 6.3 to 7.6. Application of the calcium chelator, ethylene-glycol-bis-(beta-aminoethylether)-N,N,N',N'-tetraacetic acid, greatly decreased basipetal auxin movement, reducing polarity from 6.3 to 3.7. Transport of label after application of tritiated abscisic acid showed no polarity and was not affected by calcium or aluminum. The results indicate that the root cap is particularly important in maintaining basipetal polarity of auxin transport in primary roots of corn. The induction of root curvature by unilateral application of aluminum or calcium to root caps is likely to result from localized effects of these ions on auxin transport. The findings are discussed relative to the possible role of calcium redistribution in the gravitropic curvature of roots and the possibility of calmodulin involvement in the action of calcium and aluminum on auxin transport.

  3. Two seven-transmembrane domain MILDEW RESISTANCE LOCUS O proteins cofunction in Arabidopsis root thigmomorphogenesis.

    Science.gov (United States)

    Chen, Zhongying; Noir, Sandra; Kwaaitaal, Mark; Hartmann, H Andreas; Wu, Ming-Jing; Mudgil, Yashwanti; Sukumar, Poornima; Muday, Gloria; Panstruga, Ralph; Jones, Alan M

    2009-07-01

    Directional root expansion is governed by nutrient gradients, positive gravitropism and hydrotropism, negative phototropism and thigmotropism, as well as endogenous oscillations in the growth trajectory (circumnutation). Null mutations in phylogenetically related Arabidopsis thaliana genes MILDEW RESISTANCE LOCUS O 4 (MLO4) and MLO11, encoding heptahelical, plasma membrane-localized proteins predominantly expressed in the root tip, result in aberrant root thigmomorphogenesis. mlo4 and mlo11 mutant plants show anisotropic, chiral root expansion manifesting as tightly curled root patterns upon contact with solid surfaces. The defect in mlo4 and mlo11 mutants is nonadditive and dependent on light and nutrients. Genetic epistasis experiments demonstrate that the mutant phenotype is independently modulated by the Gbeta subunit of the heterotrimeric G-protein complex. Analysis of expressed chimeric MLO4/MLO2 proteins revealed that the C-terminal domain of MLO4 is necessary but not sufficient for MLO4 action in root thigmomorphogenesis. The expression of the auxin efflux carrier fusion, PIN1-green fluorescent protein, the pattern of auxin-induced gene expression, and acropetal as well as basipetal auxin transport are altered at the root tip of mlo4 mutant seedlings. Moreover, addition of auxin transport inhibitors or the loss of EIR1/AGR1/PIN2 function abolishes root curling of mlo4, mlo11, and wild-type seedlings. These results demonstrate that the exaggerated root curling phenotypes of the mlo4 and mlo11 mutants depend on auxin gradients and suggest that MLO4 and MLO11 cofunction as modulators of touch-induced root tropism.

  4. Inhibition of histone deacetylation alters Arabidopsis root growth in response to auxin via PIN1 degradation.

    Science.gov (United States)

    Nguyen, Hoai Nguyen; Kim, Jun Hyeok; Jeong, Chan Young; Hong, Suk-Whan; Lee, Hojoung

    2013-10-01

    Our results showed the histone deacetylase inhibitors (HDIs) control root development in Arabidopsis via regulation of PIN1 degradation. Epigenetic regulation plays a crucial role in the expression of many genes in response to exogenous or endogenous signals in plants as well as other organisms. One of epigenetic mechanisms is modifications of histone, such as acetylation and deacetylation, are catalyzed by histone acetyltransferase (HAT) and histone deacetylase (HDAC), respectively. The Arabidopsis HDACs, HDA6, and HDA19, were reported to function in physiological processes, including embryo development, abiotic stress response, and flowering. In this study, we demonstrated that histone deacetylase inhibitors (HDIs) inhibit primary root elongation and lateral root emergence. In response to HDIs treatment, the PIN1 protein was almost abolished in the root tip. However, the PIN1 gene did not show decreased expression in the presence of HDIs, whereas IAA genes exhibited increases in transcript levels. In contrast, we observed a stable level of gene expression of stress markers (KIN1 and COR15A) and a cell division marker (CYCB1). Taken together, these results suggest that epigenetic regulation may control auxin-mediated root development through the 26S proteasome-mediated degradation of PIN1 protein.

  5. The cyclic nucleotide gated cation channel AtCNGC10 traffics from the ER via Golgi vesicles to the plasma membrane of Arabidopsis root and leaf cells

    Directory of Open Access Journals (Sweden)

    Andres Marilou A

    2007-09-01

    antisense phenotypes of decreased gravitropic and cell enlargement responses, suggest roles of AtCNGC10 in modulating cation balance required for root gravitropism, cell division and growth.

  6. The microtubule associated protein END BINDING 1 represses root responses to mechanical cues.

    Science.gov (United States)

    Gleeson, Laura; Squires, Shannon; Bisgrove, Sherryl R

    2012-05-01

    The ability of roots to navigate around rocks and other debris as they grow through the soil requires a mechanism for detecting and responding to input from both touch and gravity sensing systems. The microtubule associated protein END BINDING 1b (EB1b) is involved in this process as mutants have defects responding to combinations of touch and gravity cues. This study investigates the role of EB1b in root responses to mechanical cues. We find that eb1b-1 mutant roots exhibit an increase over wild type in their response to touch and that the expression of EB1b genes in transgenic mutants restores the response to wild type levels, indicating that EB1b is an inhibitor of the response. Mutant roots are also hypersensitive to increased levels of mechanical stimulation, revealing the presence of another process that activates the response. These findings are supported by analyses of double mutants between eb1b-1 and seedlings carrying mutations in PHOSPHOGLUCOMUTASE (PGM), ALTERED RESPONSE TO GRAVITY1 (ARG1), or TOUCH3 (TCH3), genes that encode proteins involved in gravity sensing, signaling, or touch responses, respectively. A model is proposed in which root responses to mechanical cues are modulated by at least two competing regulatory processes, one that promotes touch-mediated growth and another, regulated by EB1b, which dampens root responses to touch and enhances gravitropism. © 2012. Published by Elsevier Ireland Ltd. All rights reserved.

  7. Two Seven-Transmembrane Domain MILDEW RESISTANCE LOCUS O Proteins Cofunction in Arabidopsis Root Thigmomorphogenesis[C][W

    Science.gov (United States)

    Chen, Zhongying; Noir, Sandra; Kwaaitaal, Mark; Hartmann, H. Andreas; Wu, Ming-Jing; Mudgil, Yashwanti; Sukumar, Poornima; Muday, Gloria; Panstruga, Ralph; Jones, Alan M.

    2009-01-01

    Directional root expansion is governed by nutrient gradients, positive gravitropism and hydrotropism, negative phototropism and thigmotropism, as well as endogenous oscillations in the growth trajectory (circumnutation). Null mutations in phylogenetically related Arabidopsis thaliana genes MILDEW RESISTANCE LOCUS O 4 (MLO4) and MLO11, encoding heptahelical, plasma membrane–localized proteins predominantly expressed in the root tip, result in aberrant root thigmomorphogenesis. mlo4 and mlo11 mutant plants show anisotropic, chiral root expansion manifesting as tightly curled root patterns upon contact with solid surfaces. The defect in mlo4 and mlo11 mutants is nonadditive and dependent on light and nutrients. Genetic epistasis experiments demonstrate that the mutant phenotype is independently modulated by the Gβ subunit of the heterotrimeric G-protein complex. Analysis of expressed chimeric MLO4/MLO2 proteins revealed that the C-terminal domain of MLO4 is necessary but not sufficient for MLO4 action in root thigmomorphogenesis. The expression of the auxin efflux carrier fusion, PIN1-green fluorescent protein, the pattern of auxin-induced gene expression, and acropetal as well as basipetal auxin transport are altered at the root tip of mlo4 mutant seedlings. Moreover, addition of auxin transport inhibitors or the loss of EIR1/AGR1/PIN2 function abolishes root curling of mlo4, mlo11, and wild-type seedlings. These results demonstrate that the exaggerated root curling phenotypes of the mlo4 and mlo11 mutants depend on auxin gradients and suggest that MLO4 and MLO11 cofunction as modulators of touch-induced root tropism. PMID:19602625

  8. Mechanical modelling quantifies the functional importance of outer tissue layers during root elongation and bending

    Science.gov (United States)

    Dyson, Rosemary J; Vizcay-Barrena, Gema; Band, Leah R; Fernandes, Anwesha N; French, Andrew P; Fozard, John A; Hodgman, T Charlie; Kenobi, Kim; Pridmore, Tony P; Stout, Michael; Wells, Darren M; Wilson, Michael H; Bennett, Malcolm J; Jensen, Oliver E

    2014-01-01

    Root elongation and bending require the coordinated expansion of multiple cells of different types. These processes are regulated by the action of hormones that can target distinct cell layers. We use a mathematical model to characterise the influence of the biomechanical properties of individual cell walls on the properties of the whole tissue. Taking a simple constitutive model at the cell scale which characterises cell walls via yield and extensibility parameters, we derive the analogous tissue-level model to describe elongation and bending. To accurately parameterise the model, we take detailed measurements of cell turgor, cell geometries and wall thicknesses. The model demonstrates how cell properties and shapes contribute to tissue-level extensibility and yield. Exploiting the highly organised structure of the elongation zone (EZ) of the Arabidopsis root, we quantify the contributions of different cell layers, using the measured parameters. We show how distributions of material and geometric properties across the root cross-section contribute to the generation of curvature, and relate the angle of a gravitropic bend to the magnitude and duration of asymmetric wall softening. We quantify the geometric factors which lead to the predominant contribution of the outer cell files in driving root elongation and bending. PMID:24641449

  9. Analysis of magnetic gradients to study gravitropism.

    Science.gov (United States)

    Hasenstein, Karl H; John, Susan; Scherp, Peter; Povinelli, Daniel; Mopper, Susan

    2013-01-01

    Gravitropism typically is generated by dense particles that respond to gravity. Experimental stimulation by high-gradient magnetic fields provides a new approach to selectively manipulate the gravisensing system. The movement of corn, wheat, and potato starch grains in suspension was examined with videomicroscopy during parabolic flights that generated 20 to 25 s of weightlessness. During weightlessness, a magnetic gradient was generated by inserting a wedge into a uniform, external magnetic field that caused repulsion of starch grains. The resultant velocity of movement was compared with the velocity of sedimentation under 1 g conditions. The high-gradient magnetic fields repelled the starch grains and generated a force of at least 0.6 g. Different wedge shapes significantly affected starch velocity and directionality of movement. Magnetic gradients are able to move diamagnetic compounds under weightless or microgravity conditions and serve as directional stimulus during seed germination in low-gravity environments. Further work can determine whether gravity sensing is based on force or contact between amyloplasts and statocyte membrane system.

  10. Arbuscular mycorrhizal symbiosis and methyl jasmonate avoid the inhibition of root hydraulic conductivity caused by drought.

    Science.gov (United States)

    Sánchez-Romera, Beatriz; Ruiz-Lozano, Juan Manuel; Zamarreño, Ángel María; García-Mina, José María; Aroca, Ricardo

    2016-02-01

    Hormonal regulation and symbiotic relationships provide benefits for plants to overcome stress conditions. The aim of this study was to elucidate the effects of exogenous methyl jasmonate (MeJA) application on root hydraulic conductivity (L) of Phaseolus vulgaris plants which established arbuscular mycorrhizal (AM) symbiosis under two water regimes (well-watered and drought conditions). The variation in endogenous contents of several hormones (MeJA, JA, abscisic acid (ABA), indol-3-acetic acid (IAA), salicylic acid (SA)) and the changes in aquaporin gene expression, protein abundance and phosphorylation state were analyzed. AM symbiosis decreased L under well-watered conditions, which was partially reverted by the MeJA treatment, apparently by a drop in root IAA contents. Also, AM symbiosis and MeJA prevented inhibition of L under drought conditions, most probably by a reduction in root SA contents. Additionally, the gene expression of two fungal aquaporins was upregulated under drought conditions, independently of the MeJA treatment. Plant aquaporin gene expression could not explain the behaviour of L. Conversely, evidence was found for the control of L by phosphorylation of aquaporins. Hence, MeJA addition modified the response of L to both AM symbiosis and drought, presumably by regulating the root contents of IAA and SA and the phosphorylation state of aquaporins.

  11. Diagnostic of Gravitropism-like Stabilizer of Inspection Drone Using Neural Networks

    Science.gov (United States)

    Kruglova, Tatyana; Sayfeddine, Daher; Bulgakov, Alexey

    2018-03-01

    This paper discusses the enhancement of flight stability of using an inspection drone to scan the condition of buildings on low and high altitude. Due to aerial perturbations and wakes, the drone starts to shake and may be damaged. One of the mechanical optimization methods it so add a built-in stabilizing mechanism. However, the performance of this supporting device becomes critical on certain flying heights, thus to avoid losing the drone. The paper is divided in two parts: the description of the gravitropism-like stabilizer and the diagnostic of its status using wavelet transformation and neural network classification.

  12. Gravity response mechanisms of lateral organs and the control of plant architecture in Arabidopsis

    Science.gov (United States)

    Mullen, J.; Hangarter, R.

    Most research on gravity responses in plants has focused on primary roots and shoots, which typically grow in a vertical orientation. However, the patterns of lateral organ formation and their growth orientation, which typically are not vertical, govern plant architecture. For example, in Arabidopsis, when lateral roots emerge from the primary root, they grow at a nearly horizontal orientation. As they elongate, the roots slowly curve until they eventually reach a vertical orientation. The regulation of this lateral root orientation is an important component affecting the overall root system architecture. We have found that this change in orientation is not simply due to the onset of gravitropic competence, as non-vertical lateral roots are capable of both positive and negative gravitropism. Thus, the horizontal growth of the new lateral roots is determined by what is called the gravitropic set-point angle (GSA). In Arabidopsis shoots, rosette leaves and inflorescence branches also display GSA-dependent developmental changes in their orientation. The developmental control of the GSA of lateral organs in Arabidopsis provides us with a useful system for investigating the components involved in regulating directionality of tropistic responses. We have identified several Arabidopsis mutants that have either altered lateral root orientations, altered orientation of lateral organs in the shoot, or both, but maintain normal primary organ orientation. The mgsa ({m}odified {g}ravitropic {s}et-point {a}ngle) mutants with both altered lateral root and shoot orientation show that there are common components in the regulation of growth orientation in the different organs. Rosette leaves and lateral roots also have in common a regulation of positioning by red light. Further molecular and physiological analyses of the GSA mutants will provide insight into the basis of GSA regulation and, thus, a better understanding of how gravity controls plant architecture. [This work was

  13. Total Saponin from Root of Actinidia valvata Dunn Inhibits Hepatoma 22 Growth and Metastasis In Vivo by Suppression Angiogenesis

    Directory of Open Access Journals (Sweden)

    Guo-Yin Zheng

    2012-01-01

    Full Text Available The root of Actinidia valvata dunn has been widely used in the treatment of hepatocellular carcinoma (HCC, proved to be beneficial for a longer and better life in China. In present work, total saponin from root of Actinidia valvata Dunn (TSAVD was extracted, and its effects on hepatoma H22-based mouse in vivo were observed. Primarily transplanted hypodermal hepatoma H22-based mice were used to observe TSAVD effect on tumor growth. The microvessel density (MVD, vascular endothelial growth factor (VEGF, basic fibroblast growth factor (bFGF are characterized factors of angiogenesis, which were compared between TSAVD-treated and control groups. Antimetastasis effect on experimental pulmonary metastasis hepatoma mice was also observed in the study. The results demonstrated that TSAVD can effectively inhibit HCC growth and metastasis in vivo, inhibit the formation of microvessel, downregulate expressions of VEGF and bFGF, and retrain angiogenesis of hepatoma 22 which could be one of the reasons.

  14. ARG1 (altered response to gravity) encodes a DnaJ-like protein that potentially interacts with the cytoskeleton

    Science.gov (United States)

    Sedbrook, J. C.; Chen, R.; Masson, P. H.

    1999-01-01

    Gravitropism allows plant organs to direct their growth at a specific angle from the gravity vector, promoting upward growth for shoots and downward growth for roots. Little is known about the mechanisms underlying gravitropic signal transduction. We found that mutations in the ARG1 locus of Arabidopsis thaliana alter root and hypocotyl gravitropism without affecting phototropism, root growth responses to phytohormones or inhibitors of auxin transport, or starch accumulation. The positional cloning of ARG1 revealed a DnaJ-like protein containing a coiled-coil region homologous to coiled coils found in cytoskeleton-interacting proteins. These data suggest that ARG1 participates in a gravity-signaling process involving the cytoskeleton. A combination of Northern blot studies and analysis of ARG1-GUS fusion-reporter expression in transgenic plants demonstrated that ARG1 is expressed in all organs. Ubiquitous ARG1 expression in Arabidopsis and the identification of an ortholog in Caenorhabditis elegans suggest that ARG1 is involved in other essential processes.

  15. Over-expression of mango (Mangifera indica L.) MiARF2 inhibits root and hypocotyl growth of Arabidopsis.

    Science.gov (United States)

    Wu, Bei; Li, Yun-He; Wu, Jian-Yong; Chen, Qi-Zhu; Huang, Xia; Chen, Yun-Feng; Huang, Xue-Lin

    2011-06-01

    An auxin response factor 2 gene, MiARF2, was cloned in our previous study [1] from the cotyledon section of mango (Mangifera indica L. cv. Zihua) during adventitious root formation, which shares an 84% amino acid sequence similarity to Arabidopsis ARF2. This study was to examine the effects of over-expression of the full-length MiARF2 open reading frame on the root and hypocotyl growth in Arabidopsis. Phenotype analysis showed that the T(3) transgenic lines had about 20-30% reduction in the length of hypocotyls and roots of the seedlings in comparison with the wild-type. The transcription levels of ANT and ARGOS genes which play a role in controlling organ size and cell proliferation in the transgenic seedlings also decreased. Therefore, the inhibited root and hypocotyl growth in the transgenic seedlings may be associated with the down-regulated transcription of ANT and ARGOS by the over-expression of MiARF2. This study also suggests that although MiARF2 only has a single DNA-binding domain (DBD), it can function as other ARF-like proteins containing complete DBD, middle region (MR) and carboxy-terminal dimerization domain (CTD).

  16. Gravisensing in roots

    Science.gov (United States)

    Perbal, G.

    1999-01-01

    The mode of gravisensing in higher plants is not yet elucidated. Although, it is generally accepted that the amyloplasts (statoliths) in the root cap cells (statocytes) are responsible for susception of gravity. However, the hypothesis that the whole protoplast acts as gravisusceptor cannot be dismissed. The nature of the sensor that is able to transduce and amplify the mechanical energy into a biochemical factor is even more controversial. Several cell structures could potentially serve as gravireceptors: the endoplasmic reticulum, the actin network, the plasma membrane, or the cytoskeleton associated with this membrane. The nature of the gravisusceptors and gravisensors is discussed by taking into account the characteristics of the gravitropic reaction with respect to the presentation time, the threshold acceleration, the reciprocity rule, the deviation from the sine rule, the movement of the amyloplasts, the pre-inversion effect, the response of starch free and intermediate mutants and the effects of cytochalasin treatment. From this analysis, it can be concluded that both the amyloplasts and the protoplast could be the gravisusceptors, the former being more efficient than the latter since they can focus pressure on limited areas. The receptor should be located in the plasma membrane and could be a stretch-activated ion channel.

  17. Flavonoids modify root growth and modulate expression of SHORT-ROOT and HD-ZIP III.

    Science.gov (United States)

    Franco, Danilo Miralha; Silva, Eder Marques; Saldanha, Luiz Leonardo; Adachi, Sérgio Akira; Schley, Thayssa Rabelo; Rodrigues, Tatiane Maria; Dokkedal, Anne Ligia; Nogueira, Fabio Tebaldi Silveira; Rolim de Almeida, Luiz Fernando

    2015-09-01

    Flavonoids are a class of distinct compounds produced by plant secondary metabolism that inhibit or promote plant development and have a relationship with auxin transport. We showed that, in terms of root development, Copaifera langsdorffii leaf extracts has an inhibitory effect on most flavonoid components compared with the application of exogenous flavonoids (glycosides and aglycones). These compounds alter the pattern of expression of the SHORT-ROOT and HD-ZIP III transcription factor gene family and cause morpho-physiological alterations in sorghum roots. In addition, to examine the flavonoid auxin interaction in stress, we correlated the responses with the effects of exogenous application of auxin and an auxin transport inhibitor. The results show that exogenous flavonoids inhibit primary root growth and increase the development of lateral roots. Exogenous flavonoids also change the pattern of expression of specific genes associated with root tissue differentiation. These findings indicate that flavonoid glycosides can influence the polar transport of auxin, leading to stress responses that depend on auxin. Copyright © 2015 Elsevier GmbH. All rights reserved.

  18. Halogenated auxins affect microtubules and root elongation in Lactuca sativa

    Science.gov (United States)

    Zhang, N.; Hasenstein, K. H.

    2000-01-01

    We studied the effect of 4,4,4-trifluoro-3-(indole-3-)butyric acid (TFIBA), a recently described root growth stimulator, and 5,6-dichloro-indole-3-acetic acid (DCIAA) on growth and microtubule (MT) organization in roots of Lactuca sativa L. DCIAA and indole-3-butyric acid (IBA) inhibited root elongation and depolymerized MTs in the cortex of the elongation zone, inhibited the elongation of stele cells, and promoted xylem maturation. Both auxins caused the plane of cell division to shift from anticlinal to periclinal. In contrast, TFIBA (100 micromolar) promoted elongation of primary roots by 40% and stimulated the elongation of lateral roots, even in the presence of IBA, the microtubular inhibitors oryzalin and taxol, or the auxin transport inhibitor naphthylphthalamic acid. However, TFIBA inhibited the formation of lateral root primordia. Immunostaining showed that TFIBA stabilized MTs orientation perpendicular to the root axis, doubled the cortical cell length, but delayed xylem maturation. The data indicate that the auxin-induced inhibition of elongation and swelling of roots results from reoriented phragmoplasts, the destabilization of MTs in elongating cells, and promotion of vessel formation. In contrast, TFIBA induced promotion of root elongation by enhancing cell length, prolonging transverse MT orientation, delaying cell and xylem maturation.

  19. The effect of ethylene on root growth of Zea mays seedlings

    Science.gov (United States)

    Whalen, M. C.; Feldman, L. J.

    1988-01-01

    The control of primary root growth in Zea mays cv. Merit by ethylene was examined. At applied concentrations of ethylene equal to or greater than 0.1 microliter L-1, root elongation during 24 h was inhibited. The half-maximal response occurred at 0.6 microliter L-1 and the response saturated at 6 microliters L-1. Inhibition of elongation took place within 20 min. However, after ethylene was removed, elongation recovered to control values within 15 min. Root elongation was also inhibited by green light. The inhibition caused by a 24-h exposure to ethylene was restricted to the elongating region just behind the apex, with inhibition of cortical cell elongation being the primary contributor to the effect. Based on use of 2,5-norbornadiene, a gaseous competitive inhibitor of ethylene, it was concluded that endogenous ethylene normally inhibits root elongation.

  20. Root-growth-inhibiting sheet

    Science.gov (United States)

    Burton, F.G.; Cataldo, D.A.; Cline, J.F.; Skiens, W.E.; Van Voris, P.

    1993-01-26

    In accordance with this invention, a porous sheet material is provided at intervals with bodies of a polymer which contain a 2,6-dinitroaniline. The sheet material is made porous to permit free passage of water. It may be either a perforated sheet or a woven or non-woven textile material. A particularly desirable embodiment is a non-woven fabric of non-biodegradable material. This type of material is known as a geotextile'' and is used for weed control, prevention of erosion on slopes, and other landscaping purposes. In order to obtain a root repelling property, a dinitroaniline is blended with a polymer which is attached to the geotextile or other porous material.

  1. Root-growth-inhibiting sheet

    Science.gov (United States)

    Burton, Frederick G.; Cataldo, Dominic A.; Cline, John F.; Skiens, W. Eugene; Van Voris, Peter

    1993-01-01

    In accordance with this invention, a porous sheet material is provided at intervals with bodies of a polymer which contain a 2,6-dinitroaniline. The sheet material is made porous to permit free passage of water. It may be either a perforated sheet or a woven or non-woven textile material. A particularly desirable embodiment is a non-woven fabric of non-biodegradable material. This type of material is known as a "geotextile" and is used for weed control, prevention of erosion on slopes, and other landscaping purposes. In order to obtain a root repelling property, a dinitroaniline is blended with a polymer which is attached to the geotextile or other porous material.

  2. Synergistic effect of baicalein, wogonin and oroxylin A mixture: multistep inhibition of the NF-κB signalling pathway contributes to an anti-inflammatory effect of Scutellaria root flavonoids.

    Science.gov (United States)

    Shimizu, Tomofumi; Shibuya, Nobuhiko; Narukawa, Yuji; Oshima, Naohiro; Hada, Noriyasu; Kiuchi, Fumiyuki

    2018-01-01

    Scutellaria root, the root of Scutellaria baicalensis Georgi, is a crude drug used for inflammatory diseases. In our previous report, the combination of flavonoids contained in Scutellaria root have been found to inhibit PGE 2 production more strongly than individual flavonoids. Here, to investigate the mechanism of the synergistic effect, we examined the effects of an equimolar mixture (F-mix) of baicalein (1), wogonin (2) and oroxylin A (3) on the production of PGE 2 in LPS-treated J774.1 cells. Although 1 and 3 inhibited COX-2 activity, the F-mix showed no synergistic effect on COX-2 inhibition. Therefore, we investigated the steps leading to the activation of COX-2 protein. Compounds 1-3 and F-mix inhibited the expression of COX-2 protein. However, only 2 inhibited the expression of COX-2 mRNA among the flavonoids, and the F-mix showed no synergistic effect. Only 1 inhibited NF-κB translocation into the nucleus, and the F-mix showed no synergistic effect. Although 2 did not affect NF-κB translocation, it strongly inhibited NF-κB-dependent transcriptional activity, and the F-mix inhibited the activity slightly more than 2. Compounds 1-3 also inhibited NO production, and the F-mix showed a synergistic effect. However, the effects of each flavonoid on the expression of iNOS mRNA were not consistent with those on COX-2 mRNA. Because the flavonoids inhibit different steps in the production of PGE 2 and NO, and their mixture did not show apparent synergistic effects in each step, we conclude that the synergistic effect of the flavonoid mixture reflects the total effect of the flavonoids inhibiting different steps in the NF-κB signalling pathway.

  3. Shoot-derived abscisic acid promotes root growth.

    Science.gov (United States)

    McAdam, Scott A M; Brodribb, Timothy J; Ross, John J

    2016-03-01

    The phytohormone abscisic acid (ABA) plays a major role in regulating root growth. Most work to date has investigated the influence of root-sourced ABA on root growth during water stress. Here, we tested whether foliage-derived ABA could be transported to the roots, and whether this foliage-derived ABA had an influence on root growth under well-watered conditions. Using both application studies of deuterium-labelled ABA and reciprocal grafting between wild-type and ABA-biosynthetic mutant plants, we show that both ABA levels in the roots and root growth in representative angiosperms are controlled by ABA synthesized in the leaves rather than sourced from the roots. Foliage-derived ABA was found to promote root growth relative to shoot growth but to inhibit the development of lateral roots. Increased root auxin (IAA) levels in plants with ABA-deficient scions suggest that foliage-derived ABA inhibits root growth through the root growth-inhibitor IAA. These results highlight the physiological and morphological importance, beyond the control of stomata, of foliage-derived ABA. The use of foliar ABA as a signal for root growth has important implications for regulating root to shoot growth under normal conditions and suggests that leaf rather than root hydration is the main signal for regulating plant responses to moisture. © 2015 John Wiley & Sons Ltd.

  4. Calcium ion dependency of ethylene production in segments of primary roots of Zea mays

    Science.gov (United States)

    Hasenstein, K. H.; Evans, M. L.

    1986-01-01

    We investigated the effect of Ca2+ on ethylene production in 2-cm long apical segments from primary roots of corn (Zea mays L., B73 x Missouri 17) seedlings. The seedlings were raised under different conditions of Ca2+ availability. Low-Ca and high-Ca seedlings were raised by soaking the grains and watering the seedlings with distilled water or 10 mM CaCl2, respectively. Segments from high-Ca roots produced more than twice as much ethylene as segments from low-Ca roots. Indoleacetic acid (IAA; 1 micromole) enhanced ethylene production in segments from both low-Ca and high-Ca roots but auxin-induced promotion of ethylene production was consistently higher in segments from high-Ca roots. Addition of 1-aminocyclopropane-1-carboxylic acid (ACC) to root segments from low-Ca seedlings doubled total ethylene production and the rate of production remained fairly constant during a 24 h period of monitoring. In segments from high-Ca seedlings ACC also increased total ethylene production but most of the ethylene was produced within the first 6 h. The data suggest that Ca2+ enhances the conversion of ACC to ethylene. The terminal 2 mm of the root tip were found to be especially important to ethylene biosynthesis by apical segments and, experiments using 45Ca2+ as tracer indicated that the apical 2 mm of the root is the region of strongest Ca2+ accumulation. Other cations such as Mn2+, Mg2+, and K+ could largely substitute for Ca2+. The significance of these findings is discussed with respect to recent evidence for gravity-induced Ca2+ redistribution and its relationship to the establishment of asymmetric growth during gravitropic curvature.

  5. Heuristic Aspect of the Lateral Root Initiation Index: A Case Study of the Role of Nitric Oxide in Root Branching

    Directory of Open Access Journals (Sweden)

    Veronica Lira-Ruan

    2013-10-01

    Full Text Available Premise of the study: Lateral root (LR initiation (LRI is a central process in root branching. Based on LR and/or LR primordium densities, it has been shown that nitric oxide (NO promotes LRI. However, because NO inhibits primary root growth, we hypothesized that NO may have an opposite effect if the analysis is performed on a cellular basis. Using a previously proposed parameter, the LRI index (which measures how many LRI events take place along a root portion equivalent to the length of a single file of 100 cortical cells of average length, we addressed this hypothesis and illustrate here that the LRI index provides a researcher with a tool to uncover hidden but important information about root initiation. Methods and Results: Arabidopsis thaliana roots were treated with an NO donor (sodium nitroprusside [SNP] and/or an NO scavenger (2-(4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-l-oxyl-3-oxide [cPTIO]. LRI was analyzed separately in the root portions formed before and during the treatment. In the latter, SNP caused root growth inhibition and an increase in the LR density accompanied by a decrease in LRI index, indicating overall inhibitory outcome of the NO donor on branching. The inhibitory effect of SNP was reversed by cPTIO, showing the NO-specific action of SNP on LRI. Conclusions: Analysis of the LRI index permits the discovery of otherwise unknown modes of action of a substance on the root system formation. NO has a dual action on root branching, slightly promoting it in the root portion formed before the treatment and strongly inhibiting it in the root portion formed during the treatment.

  6. Inhibition of Insulin like growth factor-I expression by chromatographic fraction of Polygonum hydropiper root reduces implantation preference in rat

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    Pranjiv Goswami

    2014-03-01

    Major conclusions: The root of P. hydropiper contains compound(s with capability to modulate transcription and expression of IGF-I in rat uterus during early gestation. Down regulation of IGF-I results suggests that the phytocompound(s work through the ovarian steroid receptor(s resulting in an inhibition of decidual cell reaction and implantation.

  7. Inhibition of Human Cervical Cancer Cell Growth by Ethanolic Extract of Boerhaavia diffusa Linn. (Punarnava Root

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    Rakhi Srivastava

    2011-01-01

    Full Text Available In Indian traditional medicine, Boerhaavia diffusa (punarnava roots have been widely used for the treatment of dyspepsia, jaundice, enlargement of spleen, abdominal pain and as an anti-stress agent. Pharmacological evaluation of the crude ethanolic extract of B. diffusa roots has been shown to possess antiproliferative and immunomodulatory properties. The extract of B. diffusa was studied for anti-proliferative effects on the growth of HeLa cells and for its effect on cell cycle. Bio-assays of extracts from B. diffusa root showed that a methanol : chloroform fraction (BDF 5 had an antiproliferative effect on HeLa cells. After 48 h of exposure, this fraction at a concentration of 200 μg mL−1 significantly reduced cell proliferation with visible morphological changes in HeLa cells. Cell cycle analysis suggests that antiproliferative effect of BDF 5 could be due to inhibition of DNA synthesis in S-phase of cell cycle in HeLa cells, whereas no significant change in cell cycle was detected in control cells. The fraction BDF 5 caused cell death via apoptosis as evident from DNA fragmentation and caspase-9 activation. Thus the extract has potential to be evaluated in detail to assess the molecular mechanism-mediated anticancer activities of this plant.

  8. Naringenin inhibits the growth and stimulates the lignification of soybean root

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    Graciene de Souza Bido

    2010-06-01

    Full Text Available The flavanone naringenin, an intermediate in flavonoid biosynthesis, was tested for its effect on root growth, phenylalanine ammonia-lyase (PAL and peroxidase (POD activities, as well as phenolic compounds and lignin contents in soybean (Glycine max L. Merrill seedlings. Three-day-old seedlings were cultivated in half-strength Hoagland nutrient solution (pH 6.0, with or without 0.1 to 0.4 mM naringenin in a growth chamber (25°C, 12-h photoperiod, irradiance of 280 µmol m-2 s-1 for 24 h. Inhibitory effects on root growth (length, weight, cell viability, PAL and soluble POD activities were detected after naringenin treatments. These effects were associated with stimulatory activity of the cell wall-bound POD followed by an increase in the lignin contents, suggesting that naringenin-induced inhibition in soybean roots could be due to the lignification process.Os efeitos de naringenina, um intermediário da biossíntese de flavonóides, foram avaliados sobre o crescimento das raízes, as atividades da fenilalanina amônia liase (PAL e peroxidases, bem como sobre os teores de compostos fenólicos e de lignina em plântulas de soja (Glycine max L. Merrill. Plântulas de três dias foram cultivadas em solução nutritiva de Hoagland, meia-força (pH 6,0, contendo ou não, naringenina 0,1 a 0,4 mM, em uma câmara de germinação (25°C, fotoperíodo de 12 h, 280 µmol m-2 s-1 durante 24 h. Efeitos inibitórios no crescimento das raízes (comprimento, massa e viabilidade celular e nas atividades da PAL e POD solúvel foram constatados após os tratamentos com naringenina. Estes efeitos foram associados com atividade estimulatória da POD ligada à parede celular, seguido por aumento nos teores de lignina, sugerindo que a inibição do crescimento das raízes pode ser devido ao processo de lignificação.

  9. Cellular and molecular insight into the inhibition of primary root growth of Arabidopsis induced by peptaibols, a class of linear peptide antibiotics mainly produced by Trichoderma spp.

    Science.gov (United States)

    Shi, Wei-Ling; Chen, Xiu-Lan; Wang, Li-Xia; Gong, Zhi-Ting; Li, Shuyu; Li, Chun-Long; Xie, Bin-Bin; Zhang, Wei; Shi, Mei; Li, Chuanyou; Zhang, Yu-Zhong; Song, Xiao-Yan

    2016-04-01

    Trichoderma spp. are well known biocontrol agents that produce a variety of antibiotics. Peptaibols are a class of linear peptide antibiotics mainly produced by Trichoderma Alamethicin, the most studied peptaibol, is reported as toxic to plants at certain concentrations, while the mechanisms involved are unclear. We illustrated the toxic mechanisms of peptaibols by studying the growth-inhibitory effect of Trichokonin VI (TK VI), a peptaibol from Trichoderma longibrachiatum SMF2, on Arabidopsis primary roots. TK VI inhibited root growth by suppressing cell division and cell elongation, and disrupting root stem cell niche maintenance. TK VI increased auxin content and disrupted auxin response gradients in root tips. Further, we screened the Arabidopsis TK VI-resistant mutant tkr1. tkr1 harbors a point mutation in GORK, which encodes gated outwardly rectifying K(+)channel proteins. This mutation alleviated TK VI-induced suppression of K(+)efflux in roots, thereby stabilizing the auxin gradient. The tkr1 mutant also resisted the phytotoxicity of alamethicin. Our results indicate that GORK channels play a key role in peptaibol-plant interaction and that there is an inter-relationship between GORK channels and maintenance of auxin homeostasis. The cellular and molecular insight into the peptaibol-induced inhibition of plant root growth advances our understanding of Trichoderma-plant interactions. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  10. Salacia campestris root bark extract: peroxidase inhibition, antioxidant and antiradical profile

    Directory of Open Access Journals (Sweden)

    José Carlos Rebuglio Vellosa

    2009-03-01

    Full Text Available Reactive oxygen species (ROS and free radical species have been implicated in initiating or accompanying many diseases in living organisms; there is thus, a continual need for antioxidants molecules to inactivate ROS/free radicals. Many studies of plants crude extracts have demonstrated free-radical scavenging and antioxidant action. Salacia species have long been used, in several countries, as traditional medicines against certain diseases and for their anti-inflammatory properties. In this study, Salacia campestris Walp (Hippocrateaceae root bark ethanol extract (ScEtOH was assessed for its ability to scavenge free radicals and reactive oxygen species; the results were expressed as percentage inhibition of the active species. ScEtOH was efficient against studied species: DPPH radical (obtained inhibition = 30%, ABTS•+ (IC50 = 1.8±0.8 μg/mL, HOCl (IC50 = 1.7 ± 0.1 μg/mL, O2•- (obtained inhibition = 32%, and NO• (obtained inhibition = 18 %. Peroxidase activity inhibition was evaluated through the guaiacol oxidation reaction catalyzed by hemin, HRP and myeloperoxidase (MPO; data showed that ScEtOH at 10 μg/mL led to 54 and 51% of inhibition, respectively, for the hemin and HRP systems. In the MPO system, ScEtOH promoted a 50% inhibition at 8.9 μg/mL, whereas quercetin, a powerful MPO inhibitor, inhibited this system at 1.35 μg/mL.Espécies reativas do oxigênio (ERO e radicais livres estão relacionados ao início ou à exacerbação de muitas doenças em organismos vivos; existindo portanto uma necessidade contínua por moléculas antioxidantes que inativem as ERO e radicais livres. Muitos estudos com extratos brutos de plantas têm demonstrado propriedades antioxidantes e seqüestradoras de radicais livres. Espécies de Salacia são utilizadas, em muitos países, como remédio tradicional contra certas doenças e por suas propriedades antiinflamatórias. Neste estudo, o extrato bruto etanólico da casca da raiz da Salacia

  11. Evaluation of allelopathic impact of aqueous extract of root and aerial root of Tinospora cordifolia (Willd. miers on some weed plants

    Directory of Open Access Journals (Sweden)

    K. M. Abdul RAOOF

    2012-05-01

    Full Text Available The present laboratory experimental study was conducted to evaluate the allelopathic potential of Tinospora cordifolia (Willd. Miers on seed germination and seedling growth of weed plants (Chenopodium album L. Chenopodium murale L., Cassia tora L. and Cassia sophera L.. Root and aerial root aqueous extracts of Tinospora at 0.5, 1.0, 2.0 and 4.0% concentrations were applied to determine their effect on seed germination and seedling growth of test plants under laboratory conditions. Germination was observed for 15 days after that the root length and shoot length was measured. Dry weight was measured after oven drying the seedlings. The aqueous extracts from root and aerial root had inhibitory effect on seed germination of test plants. Aqueous extracts from root and aerial root significantly inhibited not only germination and seedling growth but also reduced dry weight of the seedlings. Root length, shoot length of weed species decreased progressively when plants were exposed to increasing concentration (0.5, 1, 2 and 4%. Aqueous extract of aerial root shows the least inhibition. The pH of aqueous extracts of different parts of T. cordifolia does not show any major change when the concentration increases.

  12. Primary physical mechanism of different magnetic fields action on roots of some plants

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    N. V. Sheykina

    2017-12-01

    Full Text Available Background: Though the magnetic field action on biological object is proved now by many experiments it cannot be explained. The counterarguments are the small value of magnetic induction, that is effective for static magnetic field and the small value of ions free path length for ion cyclotron resonance presence.   Objectives of the article were to generalize all the results that had been obtained before in static, alternative and combined magnetic fields and to explain all results by one and the same primary physical mechanism. Materials and methods that were used to obtain experimental results were based on the using of well reproducible magnetic conditions. For this purpose 3 lays µ-metal shield and superconductive shield with warm volume were used. The artificial magnetic field was created in the shield. The objects of the investigation were roots of cress, maize and pea. Their gravitropic reaction was studied. Results and discussion: All experimental results were compared with the theories and calculations maid before and following from the three mechanisms proposed below.  It was shown that there were three physical primary mechanisms that could lead to effect of low frequency alternative and combined magnetic fields and permanent magnetic field on gravitropic reaction in plants. All of them depended on the relative location of roots, gravity and components of permanent and alternative magnetic fields between themselves. The first mechanism is based on the classic model of the rotation of ions in the plane that is perpendicular to the magnetic field direction or precession of magnetic moments round the direction of magnetic field vector. The second mechanism is connected with the piezoelectric properties of starch grain (porous piezoelectricity. This property of starch may create the change in the moving of starch grains in alternative and combined magnetic fields, and even in static one. The third mechanism is caused by the phase

  13. The relationship between profiles of plagiogravitropism and morphometry of columella cells during the development of lateral roots of Vigna angularis

    Science.gov (United States)

    Kuya, Noriyuki; Sato, Seiichi

    2011-02-01

    There has been no convincing explanation on a mechanism inducing plagiogravitropism of lateral roots. The present work deals with gravitropic features of Vignaangularis lateral roots during the course of their growth and morphometric analysis of root caps, columella cells and amyloplasts. Regardless of the magnitude of deviation of the primary root axis from the gravity vector, the newly emerging lateral roots tended to keep a constant angle to the gravity vector. They modified gravireaction several times during the course of their development: a first horizontal-growth stage when they grow in the cortex of primary roots (stage I), a sloping-down growth stage from their emergence to a length of about 1 mm (stage II), a second horizontal-growth stage from a length of about 1 mm to that of over 4 mm (stage III) and a curving-down stage thereafter (stage IV). The columella cells with amyloplasts large enough to sediment were not fully differentiated in the stage I but the turning point from the stage I to II was associated with the development of amyloplasts which were able to sediment toward the distal part of the cell. Amyloplasts were significantly small in the lateral roots over 10 mm long compared with those in ones 0-10 mm long, suggesting that they rapidly develop immediately after the lateral roots emerge from primary roots and then gradually decrease their size when the lateral roots grow over 10 mm long. This dimensional decrease of amyloplasts may be partially involved in weak gravireaction in the stage III. Evidence was not presented indicating that a switchover from the stage III to IV was connected with the dimension of root caps, the number of columella cells and the development of amyloplasts. Some factors at the molecular level rather than at the cellular and tissue levels are probably dominant to induce the stage IV.

  14. Aluminium localization and toxicity symptoms related to root growth ...

    Indian Academy of Sciences (India)

    We correlated root growth inhibition with aluminium (Al3+) localization and toxicity symptoms in rice roots using seedlings of two genotypes (tolerant and sensitive) that were exposed to different AlCl3 concentrations. Al3+ localization was evaluated by hematoxylin in primary roots and by morin in cross-sections of the root ...

  15. Comparative Transcriptome Analysis Reveal Candidate Genes Potentially Involved in Regulation of Primocane Apex Rooting in Raspberry (Rubus spp.).

    Science.gov (United States)

    Liu, Jianfeng; Ming, Yuetong; Cheng, Yunqing; Zhang, Yuchu; Xing, Jiyang; Sun, Yuqi

    2017-01-01

    Raspberries ( Rubus spp.) exhibit a unique rooting process that is initiated from the stem apex of primocane, conferring an unusual asexual mode of reproduction to this plant. However, the full complement of genes involved in this process has not been identified. To this end, the present study analyzed the transcriptomes of the Rubus primocane and floricane stem apex at three developmental stages by Digital Gene Expression profiling to identify genes that regulate rooting. Sequencing and de novo assembly yielded 26.82 Gb of nucleotides and 59,173 unigenes; 498, 7,346, 4,110, 7,900, 9,397, and 4,776 differently expressed genes were identified in paired comparisons of SAF1 (floricane at developmental stage 1) vs. SAP1 (primocane at developmental stage 1), SAF2 vs. SAP2, SAF3 vs. SAP3, SAP1 vs. SAP2, SAP1 vs. SAP3, and SAP2 vs. SAP3, respectively. SAP1 maintains an extension growth pattern; SAP2 then exhibits growth arrest and vertical (downward) gravitropic deflection; and finally, short roots begin to form on the apex of SAP3. The Kyoto Encyclopedia of Genes and Genomes enrichment analysis of SAP1 vs. SAP2 revealed 12 pathways that were activated in response to shoot growth arrest and root differentiation, including circadian rhythm-plant (ko04712) and plant hormone signal transduction (ko04075). Our results indicate that genes related to circadian rhythm, ethylene and auxin signaling, shoot growth, and root development are potentially involved in the regulation of primocane apex rooting in Rubus . These findings provide a basis for elucidating the molecular mechanisms of primocane apex rooting in this economically valuable crop.

  16. Phenotype abnormality: 42 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available 42 http://metadb.riken.jp/db/SciNetS_ria224i/cria224u1ria224u548i abnormal for trait of behavior...al quality in organ named root during process named gravitropism ... root ... abnormal ... behavioral quality

  17. Genetic analysis of gravity signal transduction in roots

    Science.gov (United States)

    Masson, Patrick; Strohm, Allison; Baldwin, Katherine

    To grow downward into the soil, roots use gravity as a guide. Specialized cells, named stato-cytes, enable this directional growth response by perceiving gravity. Located in the columella region of the cap, these cells sense a reorientation of the root within the gravity field through the sedimentation of, and/or tension/pressure exerted by, dense amyloplasts. This process trig-gers a gravity signal transduction pathway that leads to a fast alkalinization of the cytoplasm and a change in the distribution of the plasma membrane-associated auxin-efflux carrier PIN3. The latter protein is uniformly distributed within the plasma membrane on all sides of the cell in vertically oriented roots. However, it quickly accumulates at the bottom side upon gravis-timulation. This process correlates with a preferential transport of auxin to the bottom side of the root cap, resulting in a lateral gradient across the tip. This gradient is then transported to the elongation zone where it promotes differential cellular elongation, resulting in downward curvature. We isolated mutations that affect gravity signal transduction at a step that pre-cedes cytoplasmic alkalinization and/or PIN3 relocalization and lateral auxin transport across the cap. arg1 and arl2 mutations identify a common genetic pathway that is needed for all three gravity-induced processes in the cap statocytes, indicating these genes function early in the pathway. On the other hand, adk1 affects gravity-induced PIN3 relocalization and lateral auxin transport, but it does not interfere with cytoplasmic alkalinization. ARG1 and ARL2 encode J-domain proteins that are associated with membranes of the vesicular trafficking path-way whereas ADK1 encodes adenosine kinase, an enzyme that converts adenosine derived from nucleic acid metabolism and the AdoMet cycle into AMP, thereby alleviating feedback inhibi-tion of this important methyl-donor cycle. Because mutations in ARG1 (and ARL2) do not completely eliminate

  18. Transcriptome responses to aluminum stress in roots of aspen (Populus tremula

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    Grisel Nadine

    2010-08-01

    Full Text Available Abstract Background Ionic aluminum (mainly Al3+ is rhizotoxic and can be present in acid soils at concentrations high enough to inhibit root growth. Many forest tree species grow naturally in acid soils and often tolerate high concentrations of Al. Previously, we have shown that aspen (Populus tremula releases citrate and oxalate from roots in response to Al exposure. To obtain further insights into the root responses of aspen to Al, we investigated root gene expression at Al conditions that inhibit root growth. Results Treatment of the aspen roots with 500 μM Al induced a strong inhibition of root growth within 6 h of exposure time. The root growth subsequently recovered, reaching growth rates comparable to that of control plants. Changes in gene expression were determined after 6 h, 2 d, and 10 d of Al exposure. Replicated transcriptome analyses using the Affymetrix poplar genome array revealed a total of 175 significantly up-regulated and 69 down-regulated genes, of which 70% could be annotated based on Arabidopsis genome resources. Between 6 h and 2 d, the number of responsive genes strongly decreased from 202 to 26, and then the number of changes remained low. The responses after 6 h were characterized by genes involved in cell wall modification, ion transport, and oxidative stress. Two genes with prolonged induction were closely related to the Arabidopsis Al tolerance genes ALS3 (for Al sensitive 3 and MATE (for multidrug and toxin efflux protein, mediating citrate efflux. Patterns of expression in different plant organs and in response to Al indicated that the two aspen genes are homologs of the Arabidopsis ALS3 and MATE. Conclusion Exposure of aspen roots to Al results in a rapid inhibition of root growth and a large change in root gene expression. The subsequent root growth recovery and the concomitant reduction in the number of responsive genes presumably reflect the success of the roots in activating Al tolerance mechanisms. The

  19. N-P Fertilization Inhibits Growth of Root Hemiparasite Pedicularis kansuensis in Natural Grassland

    Science.gov (United States)

    Liu, Yanyan; Taxipulati, Teyibai; Gong, Yanming; Sui, Xiaolin; Wang, Xuezhao; Parent, Serge-Étienne; Hu, Yukun; Guan, Kaiyun; Li, Airong

    2017-01-01

    Fertilization has been shown to affect interactions between root hemiparasitic plants and their host plants, alleviating damage to the hosts by parasitism. However, as a majority of studies were conducted in pot cultivation, the influence of fertilizer application on root hemiparasites and the surrounding plant community in field conditions as well as relevant mechanisms remain unclear. We manipulated soil nutrient resources in a semi-arid subalpine grassland in the Tianshan Mountains, northwestern China, to explore the links between fertilization and plant community composition, productivity, survival, and growth of a weedy root hemiparasite (Pedicularis kansuensis). Nitrogen (at a low rate, LN, 30 kg N ha-1 year-1 as urea; or at a high rate, HN, 90 kg N ha-1 year-1 as urea) and phosphorus [100 kg ha-1 year-1 as Ca(H2PO4)2⋅H2O] were added during two growing seasons. Patterns of foliar nutrient balances were described with isometric log ratios for the different plant functional groups receiving these fertilization regimes. Fertilization with LN, HN, and P reduced above-ground biomass of P. kansuensis, with above-ground biomass in the fertilization treatments, respectively, 12, 1, and 39% of the value found in the unfertilized control. Up to three times more above-ground biomass was produced in graminoids receiving fertilizers, whereas forb above-ground biomass was virtually unchanged by the fertilization regimes and forb species richness was reduced by 52% in the HN treatment. Fertilization altered foliar nutrient balances, and distinct patterns emerged for each plant functional group. Foliar [C | P,N] balance in the plant community was negatively correlated with above-ground biomass (P = 0.03). The inhibited competitiveness of P. kansuensis, which showed a much higher [C | P,N] balance, could be attributed to reduced C assimilation rather than mineral nutrient acquisition, as shown by significant increase in foliar N and P concentrations but little increase in C

  20. Distinct modes of adventitious rooting in Arabidopsis thaliana.

    Science.gov (United States)

    Correa, L da Rocha; Troleis, J; Mastroberti, A A; Mariath, J E A; Fett-Neto, A G

    2012-01-01

    The literature describes different rooting protocols for Arabidopsis thaliana as models to study adventitious rooting, and results are generally perceived as comparable. However, there is a lack of investigations focusing on the distinct features, advantages and limitations of each method in the study of adventitious rooting with both wild-type (WT) ecotypes and their respective mutants. This investigation was undertaken to evaluate the adventitious rooting process in three different experimental systems, all using A. thaliana, analysing the same rooting parameters after transient exposure to auxin (indole-3-acetic acid) and control conditions: excised leaves, de-rooted plants and etiolated seedlings. The founding tissues and sites of origin of roots differed depending on the system used, whereas all rooting patterns were of the direct type (i.e., without callus formation). None of the systems had an absolute requirement for exogenous auxin, although rooting was enhanced by this phytohormone, with the exception of de-rooted plants, which had adventitious rooting strongly inhibited by exogenous auxin. Root elongation was much favoured in isolated leaves. Auxin-overproducing mutants could not be used in the detached leaf system due to precocious senescence; in the de-rooted plant system, these mutants had a WT-like rooting response, whereas the expression of the 'rooty' phenotype was only evident in the etiolated seedling system. Adventitious rooting of etiolated WT seedlings in the presence of exogenous auxin was inhibited by exogenous flavonoids, which act as auxin transport inhibitors; surprisingly, the flavonoid-deficient mutant chs had a lower rooting response compared to WT. Although Arabidopsis is an excellent model system to study adventitious rooting, physiological and developmental responses differed significantly, underlining the importance of avoiding data generalisation on rooting responses derived from different experimental systems with this species.

  1. Inhibition of acrolein-stimulated MUC5AC expression by Platycodon grandiflorum root-derived saponin in A549 cells.

    Science.gov (United States)

    Choi, Jae Ho; Hwang, Yong Pil; Han, Eun Hee; Kim, Hyung Gyun; Park, Bong Hwan; Lee, Hyun Sun; Park, Byung Keun; Lee, Young Chun; Chung, Young Chul; Jeong, Hye Gwang

    2011-09-01

    Mucin overproduction is a hallmark of chronic airway diseases such as chronic obstructive pulmonary disease. In this study, we investigated the inhibition of acrolein-induced expression of mucin 5, subtypes A and C (MUC5AC) by Changkil saponin (CKS) in A549 cells. Acrolein, a known toxin in tobacco smoke and an endogenous mediator of oxidative stress, increases the expression of airway MUC5AC, a major component of airway mucus. CKS, a Platycodon grandiflorum root-derived saponin, inhibited acrolein-induced MUC5AC expression and activity, through the suppression of NF-κB activation. CKS also repressed acrolein-induced phosphorylation of ERK1/2, JNK1/2, and p38MAPK, which are upstream signaling molecules that control MUC5AC expression. In addition, the MAPK inhibitors PD98059 (ERK1/2), SP600125 (JNK1/2), and SB203580 (p38 MAPK), and a PKC delta inhibitor (rottlerin; PKCδ) inhibited acrolein-induced MUC5AC expression and activity. CKS repressed acrolein-induced phosphorylation of PKCδ. Moreover, a reactive oxygen species (ROS) inhibitor, N-acetylcysteine, inhibited acrolein-induced MUC5AC expression and activity through the suppression of PKCδ and MAPK activation, and CKS repressed acrolein-induced ROS production. These results suggest that CKS suppresses acrolein-induced MUC5AC expression by inhibiting the activation of NF-κB via ROS-PKCδ-MAPK signaling. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Ethylene-auxin interactions regulate lateral root initiation and emergence in Arabidopsis thaliana.

    Science.gov (United States)

    Ivanchenko, Maria G; Muday, Gloria K; Dubrovsky, Joseph G

    2008-07-01

    Plant root systems display considerable plasticity in response to endogenous and environmental signals. Auxin stimulates pericycle cells within elongating primary roots to enter de novo organogenesis, leading to the establishment of new lateral root meristems. Crosstalk between auxin and ethylene in root elongation has been demonstrated, but interactions between these hormones in root branching are not well characterized. We find that enhanced ethylene synthesis, resulting from the application of low concentrations of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), promotes the initiation of lateral root primordia. Treatment with higher doses of ACC strongly inhibits the ability of pericycle cells to initiate new lateral root primordia, but promotes the emergence of existing lateral root primordia: behaviour that is also seen in the eto1 mutation. These effects are correlated with decreased pericycle cell length and increased lateral root primordia cell width. When auxin is applied simultaneously with ACC, ACC is unable to prevent the auxin stimulation of lateral root formation in the root tissues formed prior to ACC exposure. However, in root tissues formed after transfer to ACC, in which elongation is reduced, auxin does not rescue the ethylene inhibition of primordia initiation, but instead increases it by several fold. Mutations that block auxin responses, slr1 and arf7 arf19, render initiation of lateral root primordia insensitive to the promoting effect of low ethylene levels, and mutations that inhibit ethylene-stimulated auxin biosynthesis, wei2 and wei7, reduce the inhibitory effect of higher ethylene levels, consistent with ethylene regulating root branching through interactions with auxin.

  3. Root growth in corn and soybeans: effects of cadmium and lead on lateral root initiation

    Energy Technology Data Exchange (ETDEWEB)

    Malone, C P; Miller, R J; Koeppe, D E

    1978-02-01

    This study examines the previously reported inhibitory effects of Cd on root growth. In hydroponic experiments, 100 ..mu..g Cd/l effected a 33% inhibition of lateral root initiation of corn. The growth of corn and soybean primary roots was not reduced at Cd concentrations of 1 mg/l, and the number of lateral root initials in soybeans was not reduced at 2 mg Cd/l. The toxic effects of Cd were ameliorated by additions of Zn or by additions of Fe citrate to nutrient growth solutions. While both Zn and Fe additions did result in increased lateral root initiation, the number of initials was significantly lower than the controls. Lead had no effect on the initiation of soybean lateral roots at a concentration of 100 ..mu..g Pb/l. However, 5 mg Pb/l did effect a 21% decrease in corn lateral root initials, but this decrease could not be demonstrated with higher Pb concentrations.

  4. Effect of MET on formation and vigor of wheat roots

    International Nuclear Information System (INIS)

    Wang Bingkui; Jin Ziyu; Zhao Miaozhen; Zhao Yanshen

    1993-01-01

    Effect of MET on the formation and vigor of roots of wheat seedlings were studied. The results showed that 50 ∼ 200 ppm MET inhibited vertical elongation of roots, increased root, shoot ratio and enhanced the formation and vigor of roots. But MET had no effect on the dry weight of roots. The activity of peroxidase was decreased and the proportion of assimilates in roots was increased by MET treatment compared with the control

  5. Nitric oxide mediates strigolactone signaling in auxin and ethylene-sensitive lateral root formation in sunflower seedlings

    OpenAIRE

    Bharti, Niharika; Bhatla, Satish C

    2015-01-01

    Strigolactones (SLs) play significant role in shaping root architecture whereby auxin-SL crosstalk has been observed in SL-mediated responses of primary root elongation, lateral root formation and adventitious root (AR) initiation. Whereas GR24 (a synthetic strigolactone) inhibits LR and AR formation, the effect of SL biosynthesis inhibitor (fluridone) is just the opposite (root proliferation). Naphthylphthalamic acid (NPA) leads to LR proliferation but completely inhibits AR development. The...

  6. [Calcitonin as an alternative treatment for root resorption].

    Science.gov (United States)

    Pierce, A; Berg, J O; Lindskog, S

    1989-01-01

    Inflammatory root resorption is a common finding following trauma and will cause eventual destruction of the tooth root if left untreated. This study examined the effects of intrapulpal application of calcitonin, a hormone known to inhibit osteoclastic bone resorption, on experimental inflammatory root resorption induced in monkeys. Results were histologically evaluated using a morphometric technique and revealed that calcitonin was an effective medicament for the treatment of inflammatory root resorption. It was concluded that this hormone could be a useful therapeutic adjunct in difficult cases of external root resorption.

  7. Effects of N fertilizer on root growth in Zea mays L. seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z. R.; Rui, Y. R.; Shen, J. B.; Zhang, F. S.

    2008-07-01

    This paper reports the effects of different nitrogen (N) fertilizer levels on the growth of maize (Zea mays L.) under field conditions. The N supply was found to influence the growth of the plants, especially the roots. A high N supply significantly inhibited root elongation, and was associated with reduced root dry weight compared to controls and to plants grown with smaller supplies of N. However, no differences were seen in lateral primary root density under the different N supply conditions, nor did plant N concentration increase with high N supply. In conclusion, a high N supply not only wastes resources and pollutes the environment, it may also inhibit root growth. (Author)

  8. Effect of heavy metals on inhibition of root elongation in 23 cultivars of flax (Linum usitatissimum L.).

    Science.gov (United States)

    Soudek, Petr; Katrusáková, Adéla; Sedlácek, Lukás; Petrová, Sárka; Kocí, Vladimír; Marsík, Petr; Griga, Miroslav; Vanek, Tomás

    2010-08-01

    The effect of toxic metals on seed germination was studied in 23 cultivars of flax (Linum usitatissimum L.). Toxicity of cadmium, cobalt, copper, zinc, nickel, lead, chromium, and arsenic at five different concentrations (0.01-1 mM) was tested by standard ecotoxicity test. Root length was measured after 72 h of incubation. Elongation inhibition, EC50 value, slope, and NOEC values were calculated. Results were evaluated by principal component analysis, a multidimensional statistical method. The results showed that heavy-metal toxicity decreased in the following order: As3+>or=As5+>Cu2+>Cd2+>Co2+>Cr6+>Ni2+>Pb2+>Cr3+>Zn2+.

  9. Nature and origin of the calcium asymmetry-arising during gravitropic response in etiolated pea epicotyls

    International Nuclear Information System (INIS)

    Migliaccio, F.; Galston, A.W.

    1987-01-01

    Seven day old etiolated pea epicotyls were loaded symmetrically with 3 H-indole 3-acetic acid (IAA) or 45 Ca 2+ , then subjected to 1.5 hours of 1g gravistimulation. Epidermal peels taken from top and bottom surfaces after 90 minutes showed an increase in IAA on the lower side and of Ca 2+ on the upper side. Inhibitors of IAA movement (TIBA, 9-hydroxyfluorene carboxylic acid) block the development of both IAA and Ca 2+ asymmetries, but substances known to interfere with normal Ca 2+ transport do not significantly alter either IAA or Ca 2+ asymmetries. These substances, however, are active in modifying both Ca 2+ uptake and efflux through oat and pea leaf protoplast membranes. The authors conclude that the 45 Ca 2+ fed to pea epicotyls occurs largely in the cell wall, and that auxin movement is primary and Ca 2+ movement secondary in gravitropism. They hypothesize that apoplastic Ca 2+ changes during the graviresponse because it is displaced by H + secreted through auxin-induced proton release. This proposed mechanism is supported by localized pH experiments, in which filter paper soaked in various buffers was applied to one side of a carborundum-abraded epicotyls. Buffer at pH 3 increased calcium loss from the side to which it is applied, whereas pH 7 buffer decreases it. Moreover, 10 micromolar IAA and 1 micromolar fusicoccin, which promote H + efflux, increase Ca 2+ release from pea epicotyl segments, whereas cycloheximide, which inhibits H + efflux, has the reverse effect

  10. Circumnutation and its dependence on the gravity response in rice, morning glory and pea plants: verification by spaceflight experiments

    Science.gov (United States)

    Takahashi, Hideyuki; Kobayashi, Akie; Fujii, Nobuharu; Yano, Sachiko; Shimazu, Toru; Kim, Hyejeong; Tomita, Yuuta; Miyazawa, Yutaka

    Plant organs display helical growth movement known as circumnutation. This movement helps plant organs find suitable environmental cues. The amplitude, period and shape of the circumnutation differ depending on plant species or organs. Although the mechanism for circumnutation is unclear, it has long been argued whether circumnutation is involved with gravitropic response. Previously, we showed that shoots of weeping morning glory (we1 and we2) are impaired in not only the differentiation of endodermis (gravisensing cells) and gravitropic response, but also winding and circumnutation (Kitazawa et al., PNAS 102: 18742-18747, 2005). Here, we report a reduced circumnutation in the shoots of rice and the roots of pea mutants defective in gravitropic response. Coleoptiles of clinorotated rice seedlings and decapped roots of pea seedlings also showed a reduction of their circumnutational movement. These results suggest that circumnutation is tightly related with gravitropic response. In the proposed spaceflight experiments, “Plant Rotation”, we will verify the hypothesis that circumnutation requires gravity response, by using microgravity environment in KIBO module of the International Space Station. We will grow rice and morning glory plants under both muG and 1G conditions on orbit and monitor their growth by a camera. The downlinked images will be analyzed for the measurements of plant growth and nutational movements. This experiment will enable us to answer the question whether circumnutation depends on gravity response or not.

  11. Gravitropism in higher plant shoots. VI. Changing sensitivity to auxin in gravistimulated soybean hypocotyls

    Science.gov (United States)

    Rorabaugh, P. A.; Salisbury, F. B.

    1989-01-01

    Although the Cholodny-Went model of auxin redistribution has been used to explain the transduction phase of gravitropism for over 60 years, problems are apparent, especially with dicot stems. An alternative to an auxin gradient is a physiological gradient in which lower tissues of a horizontal stem become more sensitive than upper tissues to auxin already present. Changes in tissue sensitivity to auxin were tested by immersing marked Glycine max Merrill (soybean) hypocotyl sections in buffered auxin solutions (0, 10(-8) to 10(-2) molar indoleacetic acid) and observing bending and growth of upper and lower surfaces. The two surfaces of horizontal hypocotyl sections responded differently to the same applied auxin stimulus; hypocotyls bent up (lower half grew more) in buffer alone or in low auxin levels, but bent down (upper half grew more) in high auxin. Dose-response curves were evaluated with Michaelis-Menten kinetics, with auxin-receptor binding analogous to enzyme-substrate binding. Vmax for the lower half was usually greater than that for the upper half, which could indicate more binding sites in the lower half. Km of the upper half was always greater than that of the lower half (unmeasurably low), which could indicate that upper-half binding sites had a much lower affinity for auxin than lower-half sites. Dose-response curves were also obtained for sections scrubbed' (cuticle abraded) on top or bottom before immersion in auxin, and gravitropic memory' experiments of L. Brauner and A. Hagar (1958 Planta 51: 115-147) were duplicated. [1-14C]Indoleacetic acid penetration was equal into the two halves, and endogenous plus exogenously supplied (not radiolabeled) free auxin in the two halves (by gas chromatography-selected ion monitoring-mass spectrometry) was also equal. Thus, differential growth occurred without free auxin redistribution, contrary to Cholodny-Went but in agreement with a sensitivity model.

  12. Root cortical aerenchyma inhibits radial nutrient transport in maize (Zea mays).

    Science.gov (United States)

    Hu, Bo; Henry, Amelia; Brown, Kathleen M; Lynch, Jonathan P

    2014-01-01

    Formation of root cortical aerenchyma (RCA) can be induced by nutrient deficiency. In species adapted to aerobic soil conditions, this response is adaptive by reducing root maintenance requirements, thereby permitting greater soil exploration. One trade-off of RCA formation may be reduced radial transport of nutrients due to reduction in living cortical tissue. To test this hypothesis, radial nutrient transport in intact roots of maize (Zea mays) was investigated in two radiolabelling experiments employing genotypes with contrasting RCA. In the first experiment, time-course dynamics of phosphate loading into the xylem were measured from excised nodal roots that varied in RCA formation. In the second experiment, uptake of phosphate, calcium and sulphate was measured in seminal roots of intact young plants in which variation in RCA was induced by treatments altering ethylene action or genetic differences. In each of three paired genotype comparisons, the rate of phosphate exudation of high-RCA genotypes was significantly less than that of low-RCA genotypes. In the second experiment, radial nutrient transport of phosphate and calcium was negatively correlated with the extent of RCA for some genotypes. The results support the hypothesis that RCA can reduce radial transport of some nutrients in some genotypes, which could be an important trade-off of this trait.

  13. Genetic Analysis of Gravity Signal Transduction in Arabidopsis thaliana Seedlings

    Science.gov (United States)

    Boonsirichai, K.; Harrison, B.; Stanga, J.; Young, L.-S.; Neal, C.; Sabat, G.; Murthy, N.; Harms, A.; Sedbrook, J.; Masson, P.

    The primary roots of Arabidopsis thaliana seedlings respond to gravity stimulation by developing a tip curvature that results from differential cellular elongation on opposite flanks of the elongation zone. This curvature appears modulated by a lateral gradient of auxin that originates in the gravity-perceiving cells (statocytes) of the root cap through an apparent lateral repositioning of a component the auxin efflux carrier complex within these cells (Friml et al, 2002, Nature 415: 806-809). Unfortunately, little is known about the molecular mechanisms that govern early phases of gravity perception and signal transduction within the root-cap statocytes. We have used a molecular genetic approach to uncover some of these mechanisms. Mutations in the Arabidopsis ARG1 and ARL2 genes, which encode J-domain proteins, resulted in specific alterations in root and hypocotyl gravitropism, without pleiotropic phenotypes. Interestingly, ARG1 and ARL2 appear to function in the same genetic pathway. A combination of molecular genetic, biochemical and cell-biological approaches were used to demonstrate that ARG1 functions in early phases of gravity signal transduction within the root and hypocotyl statocytes, and is needed for efficient lateral auxin transport within the cap. The ARG1 protein is associated with components of the secretory and/or endosomal pathways, suggesting its role in the recycling of components of the auxin efflux carrier complex between plasma membrane and endosome (Boonsirichai et al, 2003, Plant Cell 15:2612-2625). Genetic modifiers of arg1-2 were isolated and shown to enhance the gravitropic defect of arg1-2, while resulting in little or no gravitropic defects in a wild type ARG1 background. A slight tendency for arg1-2;mar1-1 and arg1-2;mar2-1 double-mutant organs to display an opposite gravitropic response compared to wild type suggests that all three genes contribute to the interpretation of the gravity-vector information by seedling organs. The

  14. Space-time analysis of gravitropism in etiolated Arabidopsis hypocotyls using bioluminescence imaging of the IAA19 promoter fusion with a destabilized luciferase reporter.

    Science.gov (United States)

    Yamamoto, Kotaro T; Watahiki, Masaaki K; Matsuzaki, Jun; Satoh, Soichirou; Shimizu, Hisayo

    2017-07-01

    Imaging analysis was carried out during the gravitropic response of etiolated Arabidopsis hypocotyls, using an IAA19 promoter fusion of destabilized luciferase as a probe. From the bright-field images we obtained the local deflection angle to the vertical, A, local curvature, C, and the partial derivative of C with respect to time, [Formula: see text]. These were determined every 19.9 µm along the curvilinear length of the hypocotyl, at ~10 min intervals over a period of ~6 h after turning hypocotyls through 90° to the horizontal. Similarly from the luminescence images we measured the luminescence intensity of the convex and concave flanks of the hypocotyl as well as along the median of the hypocotyl, to determine differential expression of auxin-inducible IAA19. Comparison of these parameters as a function of time and curvilinear length shows that the gravitropic response is composed of three successive elements: the first and second curving responses and a decurving response (autostraightening). The maximum of the first curving response occurs when A is 76° along the entire length of the hypocotyl, suggesting that A is the sole determinant in this response; in contrast, the decurving response is a function of both A and C, as predicted by the newly-proposed graviproprioception model (Bastien et al., Proc Natl Acad Sci USA 110:755-760, 2013). Further, differential expression of IAA19, with higher expression in the convex flank, is observed at A = 44°, and follows the Sachs' sine law. This also suggests that IAA19 is not involved in the first curving response. In summary, the gravitropic response of Arabidopsis hypocotyls consists of multiple elements that are each determined by separate principles.

  15. Infrared light-emitting diode radiation causes gravitropic and morphological effects in dark-grown oat seedlings

    Science.gov (United States)

    Johnson, C. F.; Brown, C. S.; Wheeler, R. M.; Sager, J. C.; Chapman, D. K.; Deitzer, G. F.

    1996-01-01

    Oat (Avena sativa cv Seger) seedlings were irradiated with IR light-emitting diode (LED) radiation passed through a visible-light-blocking filter. Infrared LED irradiated seedlings exhibited differences in growth and gravitropic response when compared to seedlings grown in darkness at the same temperature. Thus, the oat seedlings in this study were able to detect IR LED radiation. These findings call into question the use of IR LED as a safe-light for some photosensitive plant response experiments. These findings also expand the defined range of wavelengths involved in radiation-gravity (light-gravity) interactions to include wavelengths in the IR region of the spectrum.

  16. The Interaction between Auxin and Nitric Oxide Regulates Root Growth in Response to Iron Deficiency in Rice

    Directory of Open Access Journals (Sweden)

    Huwei Sun

    2017-12-01

    Full Text Available Fe deficiency (-Fe is a common abiotic stress that affects the root development of plants. Auxin and nitric oxide (NO are key regulator of root growth under -Fe. However, the interactions between auxin and NO regulate root growth in response to Fe deficiency are complex and unclear. In this study, the indole-3-acetic acid (IAA and NO levels in roots, and the responses of root growth in rice to different levels of Fe supply were investigated using wild type (WT, ospin1b and osnia2 mutants. -Fe promoted LR formation but inhibited seminal root elongation. IAA levels, [3H] IAA transport, and expression levels of PIN1a-c genes in roots were reduced under -Fe, suggesting that polar auxin transport from shoots to roots was decreased. Application of IAA to -Fe seedlings restored seminal root length, but not LR density, to levels similar to those under normal Fe (+Fe, and the seminal root length was shorter in two ospin1b mutants relative to WT under +Fe, but not under -Fe, confirming that auxin transport participates in -Fe-inhibited seminal root elongation. Moreover, -Fe-induced LR density and -Fe-inhibited seminal root elongation paralleled NO production in roots. Interestingly, similar NO accumulation and responses of LR density and root elongation were observed in osnia2 mutants compared to WT, and the higher expression of NOA gene under -Fe, suggesting that -Fe-induced NO was generated via the NO synthase-like pathway rather than the nitrate reductase pathway. However, IAA could restore the functions of NO in inhibiting seminal root elongation, but did not replace the role of NO-induced LR formation under -Fe. Overall, our findings suggested that NO functions downstream of auxin in regulating LR formation; NO-inhibited seminal root elongation by decreasing meristem activity in root tips under -Fe, with the involvement of auxin.

  17. The effect of flowering on adventitious root-formation

    NARCIS (Netherlands)

    Selim, H.H.A.

    1956-01-01

    The rooting of cuttings from day-neutral tomato was not influenced by flower development, nor by SD or LD treatments of them or of the mother plants. In cuttings of the SD plant Perilla crispa flower initiation and development severely inhibited rooting. Leaves produced about 61 %

  18. Negative Phototropism of Chlorophytum comosum Roots and Their Mechanisms

    Directory of Open Access Journals (Sweden)

    Chen Juan

    2015-07-01

    Full Text Available The aerial roots of Chlorophytum comosum were grown hydroponically, allowing us to study the performance and mechanism of negative phototropism. The results of this study were as follows. All the adventitious roots and their branch roots bent away from light with a maximum curvature of approximately 88.5°. Blue-violet light prominently induced negative phototropism while red light had no effect. The root cap was the site of photo perception. Roots with shaded or divested root caps exposed to unilateral light showed no negative phototropism, but resumed their original characteristics when the shade was removed or when new root caps grew. The curvature increased when the light intensity ranged 0–110 μmol · m−2 · s−1. The negative phototropism curvature could be promoted by exogenous CaCl2 but was inhibited by exogenous LaCl3; exogenous CaCl2 could reduce the inhibitory effect of LaCl3. Unilateral light induced the horizontal transport of IAA from the irradiated side to the shaded side, resulting in an unequal distribution of IAA in both the sides, leading to negative phototropism. The horizontal transport of IAA was promoted by exogenous Ca2+ but inhibited by exogenous La3+.

  19. A functional TOC complex contributes to gravity signal transduction in Arabidopsis.

    Science.gov (United States)

    Strohm, Allison K; Barrett-Wilt, Greg A; Masson, Patrick H

    2014-01-01

    Although plastid sedimentation has long been recognized as important for a plant's perception of gravity, it was recently shown that plastids play an additional function in gravitropism. The Translocon at the Outer envelope membrane of Chloroplasts (TOC) complex transports nuclear-encoded proteins into plastids, and a receptor of this complex, Toc132, was previously hypothesized to contribute to gravitropism either by directly functioning as a gravity signal transducer or by indirectly mediating the plastid localization of a gravity signal transducer. Here we show that mutations in multiple genes encoding TOC complex components affect gravitropism in a genetically sensitized background and that the cytoplasmic acidic domain of Toc132 is not required for its involvement in this process. Furthermore, mutations in TOC132 enhance the gravitropic defect of a mutant whose amyloplasts lack starch. Finally, we show that the levels of several nuclear-encoded root proteins are altered in toc132 mutants. These data suggest that the TOC complex indirectly mediates gravity signal transduction in Arabidopsis and support the idea that plastids are involved in gravitropism not only through their ability to sediment but also as part of the signal transduction mechanism.

  20. JNK1/2 Activation by an Extract from the Roots of Morus alba L. Reduces the Viability of Multidrug-Resistant MCF-7/Dox Cells by Inhibiting YB-1-Dependent MDR1 Expression

    Directory of Open Access Journals (Sweden)

    Youn Kyung Choi

    2013-01-01

    Full Text Available Cancer cells acquire anticancer drug resistance during chemotherapy, which aggravates cancer disease. MDR1 encoded from multidrug resistance gene 1 mainly causes multidrug resistance phenotypes of different cancer cells. In this study, we demonstrate that JNK1/2 activation by an extract from the root of Morus alba L. (White mulberry reduces doxorubicin-resistant MCF-7/Dox cell viability by inhibiting YB-1 regulation of MDR1 gene expression. When MCF-7 or MCF-7/Dox cells, where MDR1 is highly expressed were treated with an extract from roots or leaves of Morus alba L., respectively, the root extract from the mulberry (REM but not the leaf extract (LEM reduced cell viabilities of both MCF-7 and MCF-7/Dox cells, which was enhanced by cotreatment with doxorubicin. REM but not LEM further inhibited YB-1 nuclear translocation and its regulation of MDR1 gene expression. Moreover, REM promoted phosphorylation of c-Jun NH2-terminal kinase 1/2 (JNK1/2 and JNK1/2 inhibitor, SP600125 and rescued REM inhibition of both MDR1 expression and viabilities in MCF-7/Dox cells. Consistently, overexpression of JNK1, c-Jun, or c-Fos inhibited YB-1-dependent MDR1 expression and reduced viabilities in MCF-7/Dox cells. In conclusion, our data indicate that REM-activated JNK-cJun/c-Fos pathway decreases the viability of MCF-7/Dox cells by inhibiting YB-1-dependent MDR1 gene expression. Thus, we suggest that REM may be useful for treating multidrug-resistant cancer cells.

  1. The Integration of Electrical Signals Originating in the Root of Vascular Plants

    Directory of Open Access Journals (Sweden)

    Javier Canales

    2018-01-01

    Full Text Available Plants have developed different signaling systems allowing for the integration of environmental cues to coordinate molecular processes associated to both early development and the physiology of the adult plant. Research on systemic signaling in plants has traditionally focused on the role of phytohormones as long-distance signaling molecules, and more recently the importance of peptides and miRNAs in building up this communication process has also been described. However, it is well-known that plants have the ability to generate different types of long-range electrical signals in response to different stimuli such as light, temperature variations, wounding, salt stress, or gravitropic stimulation. Presently, it is unclear whether short or long-distance electrical communication in plants is linked to nutrient uptake. This review deals with aspects of sensory input in plant roots and the propagation of discrete signals to the plant body. We discuss the physiological role of electrical signaling in nutrient uptake and how nutrient variations may become an electrical signal propagating along the plant.

  2. Three consecutive days of application of LED therapy is necessary to inhibit experimentally induced root resorption in rats: a microtomographic study.

    Science.gov (United States)

    Higashi, Dayla Thyeme; Andrello, Avacir Casanova; Tondelli, Pedro Marcelo; de Oliveira Toginho Filho, Dari; de Paula Ramos, Solange

    2017-01-01

    Previous studies have suggested that phototherapy may modulate orthodontic tooth movement and the incidence of root resorption. We aimed to identify a minimal dose-response relationship to LED therapy with regard to orthodontic tooth movement (OTM) and root resorption in rats. Forty-eight male Wistar rats were divided into six groups with equal and random distribution: control (C) no intervention; three daily LED irradiation (CLED); submitted only to OTM (RR); OTM and LED irradiation on the first day (LED1); OTM and two LED irradiation on the first and second days (LED2); and OTM and three LED irradiation on the first, second, and third days (LED3). Orthodontic appliance was installed in groups RR, LED1, LED2, and LED3 to promote OTM. Animals from groups CLED, LED1, LED2, and LED3 received LED therapy (940 nm, 4 J, 4 J/cm2) according to each group of treatment. After 7 days, all the animals were sacrificed. The jaws were fixed and scanned with microtomography (micro-CT). The micro-CT images were reconstructed on 2D and 3D models. These models were used to identify and measure root resorption number and dimensions (diameter, depth, and volume). The distance between the first and second molars was used to verify tooth displacement. The results showed that LED3 group had significantly lower number of root resorption. The root resorption dimensions (diameter and depth) had no significant differences among the experimental groups. LED3 group had significant tooth displacement in relation to C and CLED groups. In conclusion, three daily LED therapy doses are required to inhibit root resorption after appliance of orthodontic forces.

  3. Statistical modeling of nitrogen-dependent modulation of root system architecture in Arabidopsis thaliana.

    Science.gov (United States)

    Araya, Takao; Kubo, Takuya; von Wirén, Nicolaus; Takahashi, Hideki

    2016-03-01

    Plant root development is strongly affected by nutrient availability. Despite the importance of structure and function of roots in nutrient acquisition, statistical modeling approaches to evaluate dynamic and temporal modulations of root system architecture in response to nutrient availability have remained as widely open and exploratory areas in root biology. In this study, we developed a statistical modeling approach to investigate modulations of root system architecture in response to nitrogen availability. Mathematical models were designed for quantitative assessment of root growth and root branching phenotypes and their dynamic relationships based on hierarchical configuration of primary and lateral roots formulating the fishbone-shaped root system architecture in Arabidopsis thaliana. Time-series datasets reporting dynamic changes in root developmental traits on different nitrate or ammonium concentrations were generated for statistical analyses. Regression analyses unraveled key parameters associated with: (i) inhibition of primary root growth under nitrogen limitation or on ammonium; (ii) rapid progression of lateral root emergence in response to ammonium; and (iii) inhibition of lateral root elongation in the presence of excess nitrate or ammonium. This study provides a statistical framework for interpreting dynamic modulation of root system architecture, supported by meta-analysis of datasets displaying morphological responses of roots to diverse nitrogen supplies. © 2015 Institute of Botany, Chinese Academy of Sciences.

  4. Effects of cell suspension and cell·free culture filtrate of Pseudomonas aeruginosa in the control of root rot-root kont disease complex of tomato (Lycopersicon esculentum Mill.

    Directory of Open Access Journals (Sweden)

    I. A. Siddiqui

    2013-12-01

    Full Text Available The plant growth-promoting rhizobacterium Pseudomonas aeruginosa strain IE-6 was tested for antagonistic activity towards Meloidogyne javanica, the root-knot nematode and soilbome root-infecting fungi viz., Macrophomina phaseolina, Fusarium solani and Rhizoctonia solani under laboratory and greenhouse conditions. Cell-free culture filtrate of the bacterium caused significant reduction in egg hatching of M.javanica and inhibited radial growth of fungi in vitro. Cell-free culture filtrate also caused lyses in mycelium of F.solani. Under greenhouse conditions, soil drenches with the aqueous cell suspension or cell-free culture resulted in a considerable reduction in nematode population densities in soil and subsequent root-knot development due to M.javanica. In addition to nematode control, rhizobacterium application also inhibited root-infection caused by soilborne root~infecting fungi with significant enhancement of growth of tomato seedlings.

  5. The jasmonate receptor COI1 plays a role in jasmonate-induced lateral root formation and lateral root positioning in Arabidopsis thaliana.

    Science.gov (United States)

    Raya-González, Javier; Pelagio-Flores, Ramón; López-Bucio, José

    2012-09-15

    Jasmonic acid (JA) regulates a broad range of plant defense and developmental responses. COI1 has been recently found to act as JA receptor. In this report, we show that low micromolar concentrations of JA inhibited primary root (PR) growth and promoted lateral root (LR) formation in Arabidopsis wild-type (WT) seedlings. It was observed that the coi1-1 mutant was less sensitive to JA on pericycle cell activation to induce lateral root primordia (LRP) formation and presented alterations in lateral root positioning and lateral root emergence on bends. To investigate JA-auxin interactions important for remodeling of root system (RS) architecture, we tested the expression of auxin-inducible markers DR5:uidA and BA3:uidA in WT and coi1-1 seedlings in response to indole-3-acetic acid (IAA) and JA and analyzed the RS architecture of a suite of auxin-related mutants under JA treatments. We found that JA did not affect DR5:uidA and BA3:uidA expression in WT and coi1-1 seedlings. Our data also showed that PR growth inhibition in response to JA was likely independent of auxin signaling and that the induction of LRP required ARF7, ARF19, SLR, TIR1, AFB2, AFB3 and AXR1 loci. We conclude that JA regulation of postembryonic root development involves both auxin-dependent and independent mechanisms. Copyright © 2012 Elsevier GmbH. All rights reserved.

  6. Overexpression of the protein phosphatase 2A regulatory subunit a gene ZmPP2AA1 improves low phosphate tolerance by remodeling the root system architecture of maize.

    Directory of Open Access Journals (Sweden)

    Jiemin Wang

    Full Text Available Phosphate (Pi limitation is a constraint for plant growth and development in many natural and agricultural ecosystems. In this study, a gene encoding Zea mays L. protein phosphatase 2A regulatory subunit A, designated ZmPP2AA1, was induced in roots by low Pi availability. The function of the ZmPP2AA1 gene in maize was analyzed using overexpression and RNA interference. ZmPP2AA1 modulated root gravitropism, negatively regulated primary root (PR growth, and stimulated the development of lateral roots (LRs. A detailed characterization of the root system architecture (RSA in response to different Pi concentrations with or without indole-3-acetic acid and 1-N-naphthylphthalamic acid revealed that auxin was involved in the RSA response to low Pi availability. Overexpression of ZmPP2AA1 enhanced tolerance to Pi starvation in transgenic maize in hydroponic and soil pot experiments. An increased dry weight (DW, root-to-shoot ratio, and total P content and concentration, along with a delayed and reduced accumulation of anthocyanin in overexpressing transgenic maize plants coincided with their highly branched root system and increased Pi uptake capability under low Pi conditions. Inflorescence development of the ZmPP2AA1 overexpressing line was less affected by low Pi stress, resulting in higher grain yield per plant under Pi deprivation. These data reveal the biological function of ZmPP2AA1, provide insights into a linkage between auxin and low Pi responses, and drive new strategies for the efficient utilization of Pi by maize.

  7. PKCɛ mediates substance P inhibition of GABAA receptors-mediated current in rat dorsal root ganglion.

    Science.gov (United States)

    Li, Li; Zhao, Lei; Wang, Yang; Ma, Ke-tao; Shi, Wen-yan; Wang, Ying-zi; Si, Jun-qiang

    2015-02-01

    The mechanism underlying the modulatory effect of substance P (SP) on GABA-activated response in rat dorsal root ganglion (DRG) neurons was investigated. In freshly dissociated rat DRG neurons, whole-cell patch-clamp technique was used to record GABA-activated current and sharp electrode intracellular recording technique was used to record GABA-induced membrane depolarization. Application of GABA (1-1000 μmol/L) induced an inward current in a concentration-dependent manner in 114 out of 127 DRG neurons (89.8 %) examined with whole-cell patch-clamp recordings. Bath application of GABA (1-1000 μmol/L) evoked a depolarizing response in 236 out of 257 (91.8%) DRG neurons examined with intracellular recordings. Application of SP (0.001-1 μmol/L) suppressed the GABA-activated inward current and membrane depolarization. The inhibitory effects were concentration-dependent and could be blocked by the selective neurokinin 1 (NK1) receptors antagonist spantide but not by L659187 and SR142801 (1 μmol/L, n=7), selective antagonists of NK2 and NK3. The inhibitory effect of SP was significantly reduced by the calcium chelator BAPTA-AM, phospholipase C (PLC) inhibitor U73122, and PKC inhibitor chelerythrine, respectively. The PKA inhibitor H-89 did not affect the SP effect. Remarkably, the inhibitory effect of SP on GABA-activated current was nearly completely removed by a selective PKCε inhibitor epilon-V1-2 but not by safingol and LY333531, selective inhibitors of PKCα and PKCβ. Our results suggest that NK1 receptor mediates SP-induced inhibition of GABA-activated current and membrane depolarization by activating intracellular PLC-Ca²⁺-PKCε cascade. SP might regulate the excitability of peripheral nociceptors through inhibition of the "pre-synaptic inhibition" evoked by GABA, which may explain its role in pain and neurogenic inflammation.

  8. The hexane fraction of Ardisia crispa Thunb. A. DC. roots inhibits inflammation-induced angiogenesis

    Science.gov (United States)

    2013-01-01

    Background Ardisia crispa (Myrsinaceae) is used in traditional Malay medicine to treat various ailments associated with inflammation, including rheumatism. The plant’s hexane fraction was previously shown to inhibit several diseases associated with inflammation. As there is a strong correlation between inflammation and angiogenesis, we conducted the present study to investigate the anti-angiogenic effects of the plant’s roots in animal models of inflammation-induced angiogenesis. Methods We first performed phytochemical screening and high-performance liquid chromatography (HPLC) fingerprinting of the hexane fraction of Ardisia crispa roots ethanolic extract (ACRH) and its quinone-rich fraction (QRF). The anti-inflammatory properties of ACRH and QRF were tested using the Miles vascular permeability assay and the murine air pouch granuloma model following oral administration at various doses. Results Preliminary phytochemical screening of ACRH revealed the presence of flavonoids, triterpenes, and tannins. The QRF was separated from ACRH (38.38% w/w) by column chromatography, and was isolated to yield a benzoquinonoid compound. The ACRH and QRF were quantified by HPLC. The LD50 value of ACRH was 617.02 mg/kg. In the Miles vascular permeability assay, the lowest dose of ACRH (10 mg/kg) and all doses of QRF significantly reduced vascular endothelial growth factor (VEGF)-induced hyperpermeability, when compared with the vehicle control. In the murine air pouch granuloma model, ACRH and QRF both displayed significant and dose-dependent anti-inflammatory effects, without granuloma weight. ACRH and QRF significantly reduced the vascular index, but not granuloma tissue weight. Conclusions In conclusion, both ACRH and QRF showed potential anti-inflammatory properties in a model of inflammation-induced angiogenesis model, demonstrating their potential anti-angiogenic properties. PMID:23298265

  9. Anti-inflammatory potential of different extracts isolated from the roots of Ficus lacor buch. Hum and Murraya koenigii L. spreng

    Directory of Open Access Journals (Sweden)

    Sindhu Rakesh K.

    2014-01-01

    Full Text Available The present study was undertaken to evaluate the anti-inflammatory potential of Murraya koenigii root extracts petroleum ether, ethyl acetate and chloroform (MKPE, MKEA and MKCF, respectively and Ficus lacor aerial root extracts petroleum ether, ethyl acetate, chloroform and ethanol (FLPE , FLET, FLCF and FLET, respectively at doses of 50 and 100 mg/kg body weight (b.w. using animal models of acute inflammation (carrageenan-, histamine- and serotonin-induced inflammation. The results of the Murraya koenigii roots chloroform extract caused 66.4% inhibition and the ethanol extract of Ficus lacor aerial roots caused 68.3% inhibition at the dose of 50 mg/kg b.w. At a higher dose of 100 mg/kg b.w., MKPE and MKCF showed 55.10% and 70.10% inhibition, respectively. FLPE and FLET showed 74.50% and 75.40% inhibition, respectively, in the carrageenan-induced inflammation model. In histamine-induced inflammation, the MKCF showed 60% inhibition, and 67.01% and 68.02% inhibition with the petroleum ether and ethanol extracts, respectively, in Ficus lacor aerial roots at the dose of 50 mg/kg b.w. At a higher dose (100 mg/kg b.w., MKCF showed 64% inhibition. FLPE and FLET showed 70.13%and 74.01% inhibition, respectively; 62.15% and 66.10% inhibition was observed with the petroleum ether and ethanol extracts of Ficus lacor aerial roots at 50 mg/kg b.w. At higher dose (100 mg/kg b.w., FLPE and FLET showed 69.10% and 68.72% inhibition in serotonin-induced inflammation.

  10. Effect of soil acidification on root growth, nutrient and water uptake

    International Nuclear Information System (INIS)

    Marschner, H.

    1989-01-01

    Soil acidification poses various types of stress to plants, especially Al and H + toxicity in roots and Mg and Ca deficiency in roots and shoots. The importance of the various types of stress varies with plant species, location and time. Average data of the chemical composition of the bulk soil or of the molar Ca/Al or Mg/Al ratios in the soil solution without consideration of the Al species are of limited value for precise conclusions of the actual, or for predictions of the potential risk of soil-acidity-induced inhibition of root growth and of nutritional imbalances. The root-induced changes in the rhizosphere and the consequences for Al toxicity and nutrient acquisition by plants deserve more attention. Further it should be considered that roots are not only required for anchoring higher plants in the soil and for nutrient and water uptake. Roots are also important sites for synthesis of phytohormones, cytokinins and abscisic acid in particular, which are transported into the shoots and act either as signals for the water status at the soil-root interface (ABA) or as compounds required for growth and development. Inhibition in root growth may therefore affect shoot growth by means other than water and nutrient supply. (orig./vhe)

  11. Physiological and Biochemical Responses to Aluminum Stress in the Root of a Biodiesel Plant Jatropha curcas L.

    Directory of Open Access Journals (Sweden)

    RADITE TISTAMA

    2012-03-01

    Full Text Available We investigated J. curcas responses to aluminum stress, histochemically and biochemically. Histochemical stainings were observed to analysis aluminum accumulation, lipid peroxidation and the loss of plasma membrane integrity on the surface and tissue of the root apex. Enzymatic analysis was conducted to measure malate content in leaf, root and malate efflux in the medium. We used M. malabathricum as a comparison for Al-tolerance plant. J. curcas root elongation was inhibited by 0.4 mM AlCl3, while M. malabathricum root elongation was inhibited by 0.8 mM AlCl3 treatment. Inhibition of root elongation has high correlation with Al accumulation in the root apex, which caused lipid degradation and cell death. Generally, malate content in J. curcas leaf and root was higher than that in M. malabathricum. In the contrary malate efflux from the root into the medium was lower. J. curcas root has a different pattern compared to M. malabathricum in malate synthesis and malate secretion when treated with a different Al concentration. We categorized J. curcas acc IP3 as more sensitive to aluminum than M. malabathricum.

  12. A plant microRNA regulates the adaptation of roots to drought stress

    KAUST Repository

    Chen, Hao

    2012-06-01

    Plants tend to restrict their horizontal root proliferation in response to drought stress, an adaptive response mediated by the phytohormone abscisic acid (ABA) in antagonism with auxin through unknown mechanisms. Here, we found that stress-regulated miR393-guided cleavage of the transcripts encoding two auxin receptors, TIR1 and AFB2, was required for inhibition of lateral root growth by ABA or osmotic stress. Unlike in the control plants, the lateral root growth of seedlings expressing miR393-resistant TIR1 or AFB2 was no longer inhibited by ABA or osmotic stress. Our results indicate that miR393-mediated attenuation of auxin signaling modulates root adaptation to drought stress. © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  13. Inhibition of acid-sensing ion channels by levo-tetrahydropalmatine in rat dorsal root ganglion neurons.

    Science.gov (United States)

    Liu, Ting-Ting; Qu, Zu-Wei; Qiu, Chun-Yu; Qiu, Fang; Ren, Cuixia; Gan, Xiong; Peng, Fang; Hu, Wang-Ping

    2015-02-01

    Levo-tetrahydropalmatine (l-THP), a main bioactive Chinese herbal constituent from the genera Stephania and Corydalis, has been in use in clinical practice for years in China as a traditional analgesic agent. However, the mechanism underlying the analgesic action of l-THP is poorly understood. This study shows that l-THP can exert an inhibitory effect on the functional activity of native acid-sensing ion channels (ASICs), which are believed to mediate pain caused by extracellular acidification. l-THP dose dependently decreased the amplitude of proton-gated currents mediated by ASICs in rat dorsal root ganglion (DRG) neurons. l-THP shifted the proton concentration-response curve downward, with a decrease of 40.93% ± 8.45% in the maximum current response to protons, with no significant change in the pH0.5 value. Moreover, l-THP can alter the membrane excitability of rat DRG neurons to acid stimuli. It significantly decreased the number of action potentials and the amplitude of the depolarization induced by an extracellular pH drop. Finally, peripherally administered l-THP inhibited the nociceptive response to intraplantar injection of acetic acid in rats. These results indicate that l-THP can inhibit the functional activity of ASICs in dissociated primary sensory neurons and relieve acidosis-evoked pain in vivo, which for the first time provides a novel peripheral mechanism underlying the analgesic action of l-THP. © 2014 Wiley Periodicals, Inc.

  14. Inhibition of tumor necrosis factor-α-induced expression of adhesion molecules in human endothelial cells by the saponins derived from roots of Platycodon grandiflorum

    International Nuclear Information System (INIS)

    Kim, Ji Young; Kim, Dong Hee; Kim, Hyung Gyun; Song, Gyu-Yong; Chung, Young Chul; Roh, Seong Hwan; Jeong, Hye Gwang

    2006-01-01

    Adhesion molecules play an important role in the development of atherogenesis and are produced by endothelial cells after being stimulated with various inflammatory cytokines. This study examined the effect of saponins that were isolated from the roots of Platycodon grandiflorum A. DC (Campanulaceae), Changkil saponins (CKS), on the cytokine-induced monocyte/human endothelial cell interaction, which is a crucial early event in atherogenesis. CKS significantly inhibited the TNFα-induced increase in monocyte adhesion to endothelial cells as well as decreased the protein and mRNA expression levels of vascular adhesion molecule-1 and intercellular cell adhesion molecule-1 on endothelial cells. Furthermore, CKS significantly inhibited the TNFα-induced production of intracellular reactive oxygen species (ROS) and activation of NF-κB by preventing IκB degradation and inhibiting IκB kinase activity. Overall, CKS has anti-atherosclerotic and anti-inflammatory activity, which is least in part the result of it reducing the cytokine-induced endothelial adhesion to monocytes by inhibiting intracellular ROS production, NF-κB activation, and cell adhesion molecule expression in endothelial cells

  15. Physiological behavior of hydrogen sulfide in rice plant. Part 5. Effect of hydrogen sulfide on respiration of rice roots

    Energy Technology Data Exchange (ETDEWEB)

    Okajima, H; Takagi, S

    1955-01-01

    The inhibitory effects of hydrogen sulfide on the respiration of rice plant roots were investigated using Warburg's manometory technique. Hydrogen sulfide inhibited not only aerobic respiration but anaerobic respiration process of roots. Inhibitory action of hydrogen sulfide and potassium cyanide on the respiration were apparently reversible, but the style of recovery reaction from inhibition was somewhat different in each case. Oxygen consumption of roots was increased by addition of ammonium salts, but the same effects were not recognized by the addition of any other salt examined (except nitrate salts). There was close relationship between respiration of roots and assimilation of nitrogen by roots. The increased oxygen uptake by addition of ammonium salt was also inhibited by hydrogen sulfide. The reactivation of this reaction occurred with the recovery of endogenous respiration of roots. 19 references, 8 figures, 3 tables.

  16. Auxin increases the hydrogen peroxide (H2O2) concentration in tomato (Solanum lycopersicum) root tips while inhibiting root growth

    NARCIS (Netherlands)

    Ivanchenko, Maria G.; den Os, Desiree; Monshausen, Gabriele B.; Dubrovsky, Joseph G.; Bednarova, Andrea; Krishnan, Natraj

    2013-01-01

    The hormone auxin and reactive oxygen species (ROS) regulate root elongation, but the interactions between the two pathways are not well understood. The aim of this study was to investigate how auxin interacts with ROS in regulating root elongation in tomato, Solanum lycopersicum. Wild-type and

  17. Establishment of a transgenic hairy root system in wild and domesticated watermelon (Citrullus lanatus) for studying root vigor under drought.

    Science.gov (United States)

    Kajikawa, Masataka; Morikawa, Kaoru; Abe, Yosuke; Yokota, Akiho; Akashi, Kinya

    2010-07-01

    Root vigor is an important trait for the growth of terrestrial plants, especially in water-deficit environments. Although deserts plants are known for their highly developed root architecture, the molecular mechanism responsible for this trait has not been determined. Here we established an efficient protocol for the genetic manipulation of two varieties of watermelon plants: a desert-grown wild watermelon that shows vigorous root growth under drought, and a domesticated cultivar showing retardation of root growth under drought stress. Agrobacterium rhizogenes-mediated transgenic hairy roots were efficiently induced and selected from the hypocotyls of these plants. Transgenic GUS expression was detected in the roots by RT-PCR and histochemical GUS staining. Moreover, a liquid culture system for evaluating their root growth was also established. Interestingly, growth of the hairy roots derived from domesticated variety of watermelon strongly inhibited under high osmotic condition, whereas the hairy roots derived from wild variety of watermelon retained substantial growth rates under the stress condition. The new protocol presented here offers a powerful tool for the comparative study of the molecular mechanism underlying drought-induced root growth in desert plants.

  18. Nitric oxide mediates strigolactone signaling in auxin and ethylene-sensitive lateral root formation in sunflower seedlings.

    Science.gov (United States)

    Bharti, Niharika; Bhatla, Satish C

    2015-01-01

    Strigolactones (SLs) play significant role in shaping root architecture whereby auxin-SL crosstalk has been observed in SL-mediated responses of primary root elongation, lateral root formation and adventitious root (AR) initiation. Whereas GR24 (a synthetic strigolactone) inhibits LR and AR formation, the effect of SL biosynthesis inhibitor (fluridone) is just the opposite (root proliferation). Naphthylphthalamic acid (NPA) leads to LR proliferation but completely inhibits AR development. The diffusive distribution of PIN1 in the provascular cells in the differentiating zone of the roots in response to GR24, fluridone or NPA treatments further indicates the involvement of localized auxin accumulation in LR development responses. Inhibition of LR formation by GR24 treatment coincides with inhibition of ACC synthase activity. Profuse LR development by fluridone and NPA treatments correlates with enhanced [Ca(2+)]cyt in the apical region and differentiating zones of LR, indicating a critical role of [Ca(2+)] in LR development in response to the coordinated action of auxins, ethylene and SLs. Significant enhancement of carotenoid cleavage dioxygenase (CCD) activity (enzyme responsible for SL biosynthesis) in tissue homogenates in presence of cPTIO (NO scavenger) indicates the role of endogenous NO as a negative modulator of CCD activity. Differences in the spatial distribution of NO in the primary and lateral roots further highlight the involvement of NO in SL-modulated root morphogenesis in sunflower seedlings. Present work provides new report on the negative modulation of SL biosynthesis through modulation of CCD activity by endogenous nitric oxide during SL-modulated LR development.

  19. Aluminium-induced reduction of plant growth in alfalfa (Medicago sativa) is mediated by interrupting auxin transport and accumulation in roots

    Science.gov (United States)

    Wang, Shengyin; Ren, Xiaoyan; Huang, Bingru; Wang, Ge; Zhou, Peng; An, Yuan

    2016-01-01

    The objective of this study was to investigate Al3+-induced IAA transport, distribution, and the relation of these two processes to Al3+-inhibition of root growth in alfalfa. Alfalfa seedlings with or without apical buds were exposed to 0 or 100 μM AlCl3 and were foliar sprayed with water or 6 mg L−1 IAA. Aluminium stress resulted in disordered arrangement of cells, deformed cell shapes, altered cell structure, and a shorter length of the meristematic zone in root tips. Aluminium stress significantly decreased the IAA concentration in apical buds and root tips. The distribution of IAA fluorescence signals in root tips was disturbed, and the IAA transportation from shoot base to root tip was inhibited. The highest intensity of fluorescence signals was detected in the apical meristematic zone. Exogenous application of IAA markedly alleviated the Al3+-induced inhibition of root growth by increasing IAA accumulation and recovering the damaged cell structure in root tips. In addition, Al3+ stress up-regulated expression of AUX1 and PIN2 genes. These results indicate that Al3+-induced reduction of root growth could be associated with the inhibitions of IAA synthesis in apical buds and IAA transportation in roots, as well as the imbalance of IAA distribution in root tips. PMID:27435109

  20. Strigolactones suppress adventitious rooting in Arabidopsis and pea.

    Science.gov (United States)

    Rasmussen, Amanda; Mason, Michael Glenn; De Cuyper, Carolien; Brewer, Philip B; Herold, Silvia; Agusti, Javier; Geelen, Danny; Greb, Thomas; Goormachtig, Sofie; Beeckman, Tom; Beveridge, Christine Anne

    2012-04-01

    Adventitious root formation is essential for the propagation of many commercially important plant species and involves the formation of roots from nonroot tissues such as stems or leaves. Here, we demonstrate that the plant hormone strigolactone suppresses adventitious root formation in Arabidopsis (Arabidopsis thaliana) and pea (Pisum sativum). Strigolactone-deficient and response mutants of both species have enhanced adventitious rooting. CYCLIN B1 expression, an early marker for the initiation of adventitious root primordia in Arabidopsis, is enhanced in more axillary growth2 (max2), a strigolactone response mutant, suggesting that strigolactones restrain the number of adventitious roots by inhibiting the very first formative divisions of the founder cells. Strigolactones and cytokinins appear to act independently to suppress adventitious rooting, as cytokinin mutants are strigolactone responsive and strigolactone mutants are cytokinin responsive. In contrast, the interaction between the strigolactone and auxin signaling pathways in regulating adventitious rooting appears to be more complex. Strigolactone can at least partially revert the stimulatory effect of auxin on adventitious rooting, and auxin can further increase the number of adventitious roots in max mutants. We present a model depicting the interaction of strigolactones, cytokinins, and auxin in regulating adventitious root formation.

  1. Fertilizer application and root development analyzed by neutron imaging

    International Nuclear Information System (INIS)

    Nihei, Naoto; Tanoi, Keitaro; Nakanishi, Tomoko M.

    2013-01-01

    We studied the development of the soybean root system under different application of fertilizer applying neutron imaging technique. When neutron beam was irradiated, the root image as well as fertilizer imbedded in a thin aluminum container was clearly projected, since water amount in roots are higher than that in soil. Through image analysis, the development of root system was studied under different application of the fertilizer. The development of a main root with lateral roots was observed without applying fertilizer. When the fertilizer was homogeneously supplied to the soil, the morphological development of the root showed the similar pattern to that grown without fertilizer, in different to the amount of the fertilizer. In the case of local application of the fertilizer, lateral position or downward to the main root, the inhibition of the root growth was observed, suggesting that the localization of the fertilizer is responsible for reduction of the soybean yield. (author)

  2. Colonization of lettuce rhizosphere and roots by tagged Streptomyces.

    Science.gov (United States)

    Bonaldi, Maria; Chen, Xiaoyulong; Kunova, Andrea; Pizzatti, Cristina; Saracchi, Marco; Cortesi, Paolo

    2015-01-01

    Beneficial microorganisms are increasingly used in agriculture, but their efficacy often fails due to limited knowledge of their interactions with plants and other microorganisms present in rhizosphere. We studied spatio-temporal colonization dynamics of lettuce roots and rhizosphere by genetically modified Streptomyces spp. Five Streptomyces strains, strongly inhibiting in vitro the major soil-borne pathogen of horticultural crops, Sclerotinia sclerotiorum, were transformed with pIJ8641 plasmid harboring an enhanced green fluorescent protein marker and resistance to apramycin. The fitness of transformants was compared to the wild-type strains and all of them grew and sporulated at similar rates and retained the production of enzymes and selected secondary metabolites as well as in vitro inhibition of S. sclerotiorum. The tagged ZEA17I strain was selected to study the dynamics of lettuce roots and rhizosphere colonization in non-sterile growth substrate. The transformed strain was able to colonize soil, developing roots, and rhizosphere. When the strain was inoculated directly on the growth substrate, significantly more t-ZEA17I was re-isolated both from the rhizosphere and the roots when compared to the amount obtained after seed coating. The re-isolation from the rhizosphere and the inner tissues of surface-sterilized lettuce roots demonstrated that t-ZEA17I is both rhizospheric and endophytic.

  3. Dehydrocostus lactone is exuded from sunflower roots and stimulates germination of the root parasite Orobanche cumana.

    Science.gov (United States)

    Joel, Daniel M; Chaudhuri, Swapan K; Plakhine, Dina; Ziadna, Hammam; Steffens, John C

    2011-05-01

    The germination of the obligate root parasites of the Orobanchaceae depends on the perception of chemical stimuli from host roots. Several compounds, collectively termed strigolactones, stimulate the germination of the various Orobanche species, but do not significantly elicit germination of Orobanche cumana, a specific parasite of sunflower. Phosphate starvation markedly decreased the stimulatory activity of sunflower root exudates toward O. cumana, and fluridone - an inhibitor of the carotenoid biosynthesis pathway - did not inhibit the production of the germination stimulant in both shoots and roots of young sunflower plants, indicating that the stimulant is not a strigolactone. We identified the natural germination stimulant from sunflower root exudates by bioassay-driven purification. Its chemical structure was elucidated as the guaianolide sesquiterpene lactone dehydrocostus lactone (DCL). Low DCL concentrations effectively stimulate the germination of O. cumana seeds but not of Phelipanche aegyptiaca (syn. Orobanche aegyptiaca). DCL and other sesquiterpene lactones were found in various plant organs, but were previously not known to be exuded to the rhizosphere where they can interact with other organisms. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. [Antimicrobial effect of a new bio-ceramic material iRoot FM on Porphyromonas endodontalis].

    Science.gov (United States)

    Bi, Jing; Liu, Yao; Chen, Xu

    2017-10-01

    To compare the antimicrobial effect of a new bio-ceramic material iRoot FM with traditional intracanal medicaments including calcium hydroxide [Ca(OH) 2 ] and triple antibiotic paste (TAP), on Porphyromonas endodontalis (P. endodontalis), and to evaluate the antimicrobial activity of iRoot FM, providing reference for clinical use of intracanal medicaments. P. endodontalis ATCC 35406 were used in this study. The study was divided into 3 experimental groups including iRoot FM, Ca(OH) 2 and TAP group. Sterile water was used as blank control. Frozen P. endodontalis were seeded and grown overnight in the liquid medium, then P. endodontalis were seeded on BHI-blood agar plates. After the plates were dried, the materials were filled on the plates which were made by a punching machine. Zones of inhibition (mm) were measured after 72 h of anaerobic incubation at 37degrees centigrade. The experimental data were analyzed statistically using SPSS 17.0 software package. The zones of inhibition in the 3 experimental groups: iRoot FM, Ca(OH) 2 and TAP group were (20.74±4.35)mm, (24.89±3.84)mm and (34.51±1.20)mm, respectively. The zones of inhibition of the iRoot FM group and Ca(OH) 2 group were significantly smaller compared with the TAP group (P0.05). There were no zone of inhibition in the control group. As a new bio-ceramic material, iRoot FM shows a good antimicrobial activity against P. endodontalis and may be a promising intracanal material.

  5. Anti-Alzheimer's disease activity of compounds from the root bark of Morus alba L.

    Science.gov (United States)

    Kuk, Eun Bi; Jo, A Ra; Oh, Seo In; Sohn, Hee Sook; Seong, Su Hui; Roy, Anupom; Choi, Jae Sue; Jung, Hyun Ah

    2017-03-01

    The inhibition of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and β-site amyloid precursor protein cleaving enzyme 1 (BACE1) plays important roles in prevention and treatment of Alzheimer's disease (AD). Among the individual parts of Morus alba L. including root bark, branches, leaves, and fruits, the root bark showed the most potent enzyme inhibitory activities. Therefore, the aim of this study was to evaluate the anti-AD activity of the M. alba root bark and its isolate compounds, including mulberrofuran G (1), albanol B (2), and kuwanon G (3) via inhibition of AChE, BChE, and BACE1. Compounds 1 and 2 showed strong AChE- and BChE-inhibitory activities; 1-3 showed significant BACE1 inhibitory activity. Based on the kinetic study with AChE and BChE, 2 and 3 showed noncompetitive-type inhibition; 1 showed mixed-type inhibition. Moreover, 1-3 showed mixed-type inhibition against BACE1. The molecular docking simulations of 1-3 demonstrated negative binding energies, indicating a high affinity to AChE and BACE1. The hydroxyl group of 1-3 formed hydrogen bond with the amino acid residues located at AChE and BACE1. Consequently, these results indicate that the root bark of M. alba and its active compounds might be promising candidates for preventive and therapeutic agents for AD.

  6. Polyamines and meristematic activity in Zea mays roots

    International Nuclear Information System (INIS)

    Schwartz, M.; Arzee, T.; Cohen, Y.; Altman, A.

    1989-01-01

    Polyamine content and biosynthesis were determined in conjunction with meristematic activity and growth of Zea mays roots. Three types of developmental events were investigated: growth of intact primary roots, formation of lateral root primordia following main root decapitation, and activity of the quiescent center following root cap excision. A low ratio of putrescine/spermidine cotents was found to be salient feature of regions with high meristematic activity, in all 3 experimental systems. Arginine decarboxylase (ADC) and ornithine decarboxylase (ODC) activities increased concomitantly with lateral root primordia development and activation of the quiescent center. An increase in the incorporation of arginine and ornithine into spermidine was found in meristematic zones. L-canavanine inhibited primary root elongation and formation of lateral primordia as well as ADC and ODC activity. Similar inhibitory effects were found with MGBG and CHA, both inhibitors of polyamine biosynthesis. A parallel study of ODC localization and DNA synthesis (using α- 14 C-DFMO and 3 H-thymidine microautoradiography, respectively) revealed than root zones with high meristematic activity are characterized by high ODC activity

  7. Polyamine-Induced Rapid Root Abscission in Azolla pinnata.

    Science.gov (United States)

    Gurung, Sushma; Cohen, Michael F; Fukuto, Jon; Yamasaki, Hideo

    2012-01-01

    Floating ferns of the genus Azolla detach their roots under stress conditions, a unique adaptive response termed rapid root abscission. We found that Azolla pinnata plants exhibited dose-dependent rapid root abscission in response to the polyamines spermidine and spermine after a substantial time lag (>20 min). The duration of the time lag decreased in response to high pH and high temperature whereas high light intensity increased the time lag and markedly lowered the rate of abscission. The oxidation products of polyamines, 1,3-diaminopropane, β-alanine and hydrogen peroxide all failed to initiate root abscission, and hydroxyethyl hydrazine, an inhibitor of polyamine oxidase, did not inhibit spermine-induced root abscission. Exposure of A. pinnata to the polyamines did not result in detectable release of NO and did not affect nitrite-dependent NO production. The finding of polyamine-induced rapid root abscission provides a facile assay for further study of the mode of action of polyamines in plant stress responses.

  8. Colonization of lettuce rhizosphere and roots by tagged Streptomyces

    Directory of Open Access Journals (Sweden)

    Maria eBonaldi

    2015-02-01

    Full Text Available Beneficial microorganisms are increasingly used in agriculture, but their efficacy often fails due to limited knowledge of their interactions with plants and other microorganisms present in rhizosphere. We studied spatio-temporal colonization dynamics of lettuce roots and rhizosphere by genetically modified Streptomyces spp. Five Streptomyces strains, strongly inhibiting in vitro the major soil-borne pathogen of horticultural crops, Sclerotinia sclerotiorum, were transformed with pIJ8641 plasmid harboring an enhanced green fluorescent protein marker and resistance to apramycin. The fitness of transformants was compared to the wild-type strains and all of them grew and sporulated at similar rates and retained the production of enzymes and selected secondary metabolites as well as in vitro inhibition of S. sclerotiorum. The tagged ZEA17I strain was selected to study the dynamics of lettuce roots and rhizosphere colonization in non-sterile growth substrate. The transformed strain was able to colonize soil, developing roots and rhizosphere. When the strain was inoculated directly on the growth substrate, significantly more t-ZEA17I was re-isolated both from the rhizosphere and the roots when compared to the amount obtained after seed coating. The re-isolation from the rhizosphere and the inner tissues of surface-sterilized lettuce roots demonstrated that t-ZEA17I is both rhizospheric and endophytic.

  9. Effects of solubilization on the inhibition of the p-type ATPase from maize roots by N-(ethoxycarbonyl)-2-ethoxy-1,2-dihydroquinoline.

    Science.gov (United States)

    Brauer, D K; Gurriel, M; Tu, S I

    1992-12-01

    The biochemical events utilized by transport proteins to convert the chemical energy from the hydrolysis of ATP into an electro-chemical gradient are poorly understood. The inhibition of the plasma membrane ATPase from corn (Zea mays L.) roots by N-(ethoxycarbonyl)-2-ethoxy-1,2-dihydroquinoline (EEDQ) was compared to that of ATPase solubilized with N-tetradecyl-N,N-dimethyl-3-ammonio-1-propane-sulfonate (3-14) to provide insight into the minimal functional unit. The chromatographic behavior of the 3-14-solubilized ATPase activity during size exclusion chromatography and glycerol gradient centrifugation indicated that the solubilized enzyme was in a monomeric form. Both plasma membrane-bound and solubilized ATPase were inhibited by EEDQ in a time- and concentration-dependent manner consistent with a first-order reaction. When the log of the reciprocal of the half-time for inhibition was plotted as a function of the log of the EEDQ concentration, straight lines were obtained with slopes of approximately 0.5 and 1.0 for membrane-bound and 3-14-solubilized ATPase, respectively, indicating a change in the number of polypeptides per functional ATPase complex induced by solubilization with 3-14.

  10. Effect of microcystins on root growth, oxidative response, and exudation of rice (Oryza sativa).

    Science.gov (United States)

    Cao, Qing; Rediske, Richard R; Yao, Lei; Xie, Liqiang

    2018-03-01

    A 30 days indoor hydroponic experiment was carried out to evaluate the effect of microcystins (MCs) on rice root morphology and exudation, as well as bioaccumulation of MCs in rice. MCs were bioaccumulated in rice with the greatest concentrations being observed in the leaves (113.68μgg -1 Fresh weight (FW)) when exposed to 500μgL -1 MCs. Root activity at 500μgL -1 decreased 37%, compared to the control. MCs also induced disruption of the antioxidant system and lipid peroxidation in rice roots. Root growth was significantly inhibited by MCs. Root weight, length; surface area and volume were significantly decreased, as well as crown root number and lateral root number. After 30 days exposure to MCs, an increase was found in tartaric acid and malic acid while the other organic acids were not affected. Glycine, tyrosine, and glutamate were the only amino acids stimulated at MCs concentrations of 500μgL -1 . Similarly, dissolved organic carbon (DOC) and carbohydrate at 50 and 500μgL -1 treatments were significantly increased. The increase of DOC and carbohydrate in root exudates was due to rice root membrane permeability changes induced by MCs. Overall, this study indicated that MCs significantly inhibited rice root growth and affected root exudation. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Root Growth Optimizer with Self-Similar Propagation

    Directory of Open Access Journals (Sweden)

    Xiaoxian He

    2015-01-01

    Full Text Available Most nature-inspired algorithms simulate intelligent behaviors of animals and insects that can move spontaneously and independently. The survival wisdom of plants, as another species of biology, has been neglected to some extent even though they have evolved for a longer period of time. This paper presents a new plant-inspired algorithm which is called root growth optimizer (RGO. RGO simulates the iterative growth behaviors of plant roots to optimize continuous space search. In growing process, main roots and lateral roots, classified by fitness values, implement different strategies. Main roots carry out exploitation tasks by self-similar propagation in relatively nutrient-rich areas, while lateral roots explore other places to seek for better chance. Inhibition mechanism of plant hormones is applied to main roots in case of explosive propagation in some local optimal areas. Once resources in a location are exhausted, roots would shrink away from infertile conditions to preserve their activity. In order to validate optimization effect of the algorithm, twelve benchmark functions, including eight classic functions and four CEC2005 test functions, are tested in the experiments. We compared RGO with other existing evolutionary algorithms including artificial bee colony, particle swarm optimizer, and differential evolution algorithm. The experimental results show that RGO outperforms other algorithms on most benchmark functions.

  12. Is comfrey root more than toxic pyrrolizidine alkaloids? Salvianolic acids among antioxidant polyphenols in comfrey (Symphytum officinale L.) roots.

    Science.gov (United States)

    Trifan, Adriana; Opitz, Sebastian E W; Josuran, Roland; Grubelnik, Andreas; Esslinger, Nils; Peter, Samuel; Bräm, Sarah; Meier, Nadja; Wolfram, Evelyn

    2018-02-01

    Comfrey root preparations are used for the external treatment of joint distortions and myalgia, due to its analgesic and anti-inflammatory properties. Up to date, key activity-determining constituents of comfrey root extracts have not been completely elucidated. Therefore, we applied different approaches to further characterize a comfrey root extract (65% ethanol). The phenolic profile of comfrey root sample was characterized by HPLC-DAD-QTOF-MS/MS. Rosmarinic acid was identified as main phenolic constituent (7.55 mg/g extract). Moreover, trimers and tetramers of caffeic acid (isomers of salvianolic acid A, B and C) were identified and quantified for the first time in comfrey root. In addition, pyrrolizidine alkaloids were evaluated by HPLC-QQQ-MS/MS and acetylintermedine, acetyllycopsamine and their N-oxides were determined as major pyrrolizidine alkaloids in the comfrey root sample. Lastly, the antioxidant activity was determined using four assays: DPPH and ABTS radicals scavenging assays, reducing power assay and 15-lipoxygenase inhibition assay. Comfrey root extract exhibited significant antioxidant activities when compared to known antioxidants. Thus, comfrey root is an important source of phenolic compounds endowed with antioxidant activity which may contribute to the overall bioactivity of Symphytum preparations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Effects of rare earth oxide nanoparticles on root elongation of plants.

    Science.gov (United States)

    Ma, Yuhui; Kuang, Linglin; He, Xiao; Bai, Wei; Ding, Yayun; Zhang, Zhiyong; Zhao, Yuliang; Chai, Zhifang

    2010-01-01

    The phytotoxicity of four rare earth oxide nanoparticles, nano-CeO(2), nano-La(2)O(3), nano-Gd(2)O(3) and nano-Yb(2)O(3) on seven higher plant species (radish, rape, tomato, lettuce, wheat, cabbage, and cucumber) were investigated in the present study by means of root elongation experiments. Their effects on root growth varied greatly between different nanoparticles and plant species. A suspension of 2000 mg L(-1) nano-CeO(2) had no effect on the root elongation of six plants, except lettuce. On the contrary, 2000 mg L(-1) suspensions of nano-La(2)O(3), nano-Gd(2)O(3) and nano-Yb(2)O(3) severely inhibited the root elongation of all the seven species. Inhibitory effects of nano-La(2)O(3), nano-Gd(2)O(3), and nano-Yb(2)O(3) also differed in the different growth process of plants. For wheat, the inhibition mainly took place during the seed incubation process, while lettuce and rape were inhibited on both seed soaking and incubation process. The fifty percent inhibitory concentrations (IC(50)) for rape were about 40 mg L(-1) of nano-La(2)O(3), 20mg L(-1) of nano-Gd(2)O(3), and 70 mg L(-1) of nano-Yb(2)O(3), respectively. In the concentration ranges used in this study, the RE(3+) ion released from the nanoparticles had negligible effects on the root elongation. These results are helpful in understanding phytotoxicity of rare earth oxide nanoparticles. Copyright 2009 Elsevier Ltd. All rights reserved.

  14. Inhibition of Apical Root Resorption by Calcium Hydroxide During Orthodontic Treatment: A Case Report

    OpenAIRE

    Pacheco, Cinthia Mara da Fonseca; Pacheco, Daniela da Fonseca; Motta, Patrícia Gonçalves da

    2016-01-01

    Apical root resorption is a common outcome of orthodontic treatment. The present article reports a case of absence of apical root resorption in a left maxillary lateral incisor filled with calcium hydroxide paste throughout orthodontic movement. After orthodontic treatment was completed the tooth was subsequently obturatedwith gutta-percha and the patient followed for 18 months. The presence of a periapical lesion and the properties of calcium hydroxide as a root resorption inhibitor were dec...

  15. Effect of fluorine and of beta-indolacetic acid on the respiration of root tissue

    Energy Technology Data Exchange (ETDEWEB)

    Pilet, P E

    1964-01-01

    The auxin, beta-indolacetic acid, (BIAA) inhibited the elongation of Lens culinaris roots at all concentrations. At high concentrations fluoride had an inhibitor effect, but it had a stimulatory effect on root growth at low concentrations. BIAA mildly stimulated respiration at low concentrations and inhibited oxygen absorption at high concentrations. At concentrations stimulating respiration fluoride was found to reduce these stimulating effects caused by BIAA. Therefore, fluoride and BIAA acted as antagonists in their effect on respiration.

  16. L-Cysteine inhibits root elongation through auxin/PLETHORA and SCR/SHR pathway in Arabidopsis thaliana.

    Science.gov (United States)

    Wang, Zhen; Mao, Jie-Li; Zhao, Ying-Jun; Li, Chuan-You; Xiang, Cheng-Bin

    2015-02-01

    L-Cysteine plays a prominent role in sulfur metabolism of plants. However, its role in root development is largely unknown. Here, we report that L-cysteine reduces primary root growth in a dosage-dependent manner. Elevating cellular L-cysteine level by exposing Arabidopsis thaliana seedlings to high L-cysteine, buthionine sulphoximine, or O-acetylserine leads to altered auxin maximum in root tips, the expression of quiescent center cell marker as well as the decrease of the auxin carriers PIN1, PIN2, PIN3, and PIN7 of primary roots. We also show that high L-cysteine significantly reduces the protein level of two sets of stem cell specific transcription factors PLETHORA1/2 and SCR/SHR. However, L-cysteine does not downregulate the transcript level of PINs, PLTs, or SCR/SHR, suggesting that an uncharacterized post-transcriptional mechanism may regulate the accumulation of PIN, PLT, and SCR/SHR proteins and auxin transport in the root tips. These results suggest that endogenous L-cysteine level acts to maintain root stem cell niche by regulating basal- and auxin-induced expression of PLT1/2 and SCR/SHR. L-Cysteine may serve as a link between sulfate assimilation and auxin in regulating root growth. © 2014 Institute of Botany, Chinese Academy of Sciences.

  17. Effects of stinging nettle root extracts and their steroidal components on the Na+,K(+)-ATPase of the benign prostatic hyperplasia.

    Science.gov (United States)

    Hirano, T; Homma, M; Oka, K

    1994-02-01

    The effects of organic-solvent extracts of Urtica dioica (Urticaceae) on the Na+,K(+)-ATPase of the tissue of benign prostatic hyperplasia (BPH) were investigated. The membrane Na+,K(+)-ATPase fraction was prepared from a patient with BPH by a differential centrifugation of the tissue homogenate. The enzyme activity was inhibited by 10(-4)-10(-5) M of ouabain. The hexane extract, the ether extract, the ethyl acetate extract, and the butanol extract of the roots caused 27.6-81.5% inhibition of the enzyme activity at 0.1 mg/ml. In addition, a column extraction of stinging nettle roots using benzene as an eluent afforded efficient enzyme inhibiting activity. Steroidal components in stinging nettle roots, such as stigmast-4-en-3-one, stigmasterol, and campesterol inhibited the enzyme activity by 23.0-67.0% at concentrations ranging from 10(-3)-10(-6) M. These results suggest that some hydrophobic constituents such as steroids in the stinging nettle roots inhibited the membrane Na+,K(+)-ATPase activity of the prostate, which may subsequently suppress prostate-cell metabolism and growth.

  18. The ABA receptor PYL8 promotes lateral root growth by enhancing MYB77-dependent transcription of auxin-responsive genes.

    Science.gov (United States)

    Zhao, Yang; Xing, Lu; Wang, Xingang; Hou, Yueh-Ju; Gao, Jinghui; Wang, Pengcheng; Duan, Cheng-Guo; Zhu, Xiaohong; Zhu, Jian-Kang

    2014-06-03

    The phytohormone abscisic acid (ABA) regulates plant growth, development, and abiotic stress responses. ABA signaling is mediated by a group of receptors known as the PYR1/PYL/RCAR family, which includes the pyrabactin resistance 1-like protein PYL8. Under stress conditions, ABA signaling activates SnRK2 protein kinases to inhibit lateral root growth after emergence from the primary root. However, even in the case of persistent stress, lateral root growth eventually recovers from inhibition. We showed that PYL8 is required for the recovery of lateral root growth, following inhibition by ABA. PYL8 directly interacted with the transcription factors MYB77, MYB44, and MYB73. The interaction of PYL8 and MYB77 increased the binding of MYB77 to its target MBSI motif in the promoters of multiple auxin-responsive genes. Compared to wild-type seedlings, the lateral root growth of pyl8 mutant seedlings and myb77 mutant seedlings was more sensitive to inhibition by ABA. The recovery of lateral root growth was delayed in pyl8 mutant seedlings in the presence of ABA, and the defect was rescued by exposing pyl8 mutant seedlings to the auxin IAA (3-indoleacetic acid). Thus, PYL8 promotes lateral root growth independently of the core ABA-SnRK2 signaling pathway by enhancing the activities of MYB77 and its paralogs, MYB44 and MYB73, to augment auxin signaling. Copyright © 2014, American Association for the Advancement of Science.

  19. Effect of corn steep liquor on lettuce root rot (Fusarium oxysporum f.sp. lactucae) in hydroponic cultures.

    Science.gov (United States)

    Chinta, Yufita D; Kano, Kazuki; Widiastuti, Ani; Fukahori, Masaru; Kawasaki, Shizuka; Eguchi, Yumi; Misu, Hideyuki; Odani, Hiromitsu; Zhou, Songying; Narisawa, Kazuhiko; Fujiwara, Kazuki; Shinohara, Makoto; Sato, Tatsuo

    2014-08-01

    Recent reports indicate that organic fertilisers have a suppressive effect on the pathogens of plants grown under hydroponic systems. Furthermore, microorganisms exhibiting antagonistic activity to diseases have been observed in organic hydroponic systems. This study evaluated the effect of corn steep liquor (CSL) on controlling lettuce root rot disease [Fusarium oxysporum f.sp. lactucae (FOL)] in a hydroponic system. The effect of CSL and Otsuka A (a chemical fertiliser) on the inhibition of FOL in terms of mycelial growth inhibition was tested in vivo. Addition of CSL suppressed FOL infection rates. CSL inhibited FOL infection by 26.3-42.5% from 2 days after starting incubation. In comparison, Otsuka A inhibited FOL growth by 5.5-19.4%. In addition, four of 10 bacteria isolated from the nutrient media containing CSL exhibited inhibition zones preventing FOL mycelial growth. We found that CSL suppressed FOL in lettuce via its antifungal and biostimulatory effects. We suggest that activation of beneficial microorganisms present in CSL may be used to decrease lettuce root rot disease and contribute to lettuce root growth. © 2014 Society of Chemical Industry.

  20. WHEN STRESS AND DEVELOPMENT GO HAND IN HAND: MAIN HORMONAL CONTROLS OF ADVENTITIOUS ROOTING IN CUTTINGS

    Directory of Open Access Journals (Sweden)

    Cibele Tesser Da Costa

    2013-05-01

    Full Text Available Adventitious rooting (AR is a multifactorial response leading to new roots at the base of stem cuttings, and the establishment of a complete and autonomous plant. AR has two main phases: a induction, with a requirement for higher auxin concentration; b formation, inhibited by high auxin and in which anatomical changes take place. The first stages of this process in severed organs necessarily include wounding and water stress responses which may trigger hormonal changes that contribute to reprogram target cells that are competent to respond to rooting stimuli. At severance, the roles of jasmonate and abscisic acid are critical for wound response and perhaps sink strength establishment, although their negative roles on the cell cycle may inhibit root induction. Strigolactones may also inhibit AR. A reduced cytokinin concentration in cuttings results from the separation of the root system, whose tips are a relevant source of these root induction inhibitors. The combined increased accumulation of basipetally transported auxins from the shoot apex at the cutting base is often sufficient for AR in easy-to-root species. The role of peroxidases and phenolic compounds in auxin catabolism may be critical at these early stages right after wounding. The events leading to AR strongly depend on mother plant nutritional status, both in terms of minerals and carbohydrates, as well as on sink establishment at cutting bases. Auxins play a central role in AR. Auxin transporters control auxin canalization to target cells. There, auxins act primarily through selective proteolysis and cell wall loosening, via their receptor proteins TIR1 and ABP1. A complex microRNA circuitry is involved in the control of auxin response factors essential for gene expression in AR. After root establishment, new hormonal controls take place, with auxins being required at lower concentrations for root meristem maintenance and cytokinins needed for root tissue differentiation.

  1. Probe substrate and enzyme source-dependent inhibition of UDP ...

    African Journals Online (AJOL)

    Background: Drug-metabolizing enzymes (DMEs) inhibition based drug-drug interaction and herb-drug interaction severely challenge the R&D process of drugs or herbal ingredients. Objective: To evaluate the inhibition potential of wogonin (an important flavonoid isolated from the root of Scutellaria baicalensis) towards ...

  2. Gibberellins inhibit adventitious rooting in hybrid aspen and Arabidopsis by affecting auxin transport.

    Science.gov (United States)

    Mauriat, Mélanie; Petterle, Anna; Bellini, Catherine; Moritz, Thomas

    2014-05-01

    Knowledge of processes involved in adventitious rooting is important to improve both fundamental understanding of plant physiology and the propagation of numerous plants. Hybrid aspen (Populus tremula × tremuloïdes) plants overexpressing a key gibberellin (GA) biosynthesis gene (AtGA20ox1) grow rapidly but have poor rooting efficiency, which restricts their clonal propagation. Therefore, we investigated the molecular basis of adventitious rooting in Populus and the model plant Arabidopsis. The production of adventitious roots (ARs) in tree cuttings is initiated from the basal stem region, and involves the interplay of several endogenous and exogenous factors. The roles of several hormones in this process have been characterized, but the effects of GAs have not been fully investigated. Here, we show that a GA treatment negatively affects the numbers of ARs produced by wild-type hybrid aspen cuttings. Furthermore, both hybrid aspen plants and intact Arabidopsis seedlings overexpressing AtGA20ox1, PttGID1.1 or PttGID1.3 genes (with a 35S promoter) produce few ARs, although ARs develop from the basal stem region of hybrid aspen and the hypocotyl of Arabidopsis. In Arabidopsis, auxin and strigolactones are known to affect AR formation. Our data show that the inhibitory effect of GA treatment on adventitious rooting is not mediated by perturbation of the auxin signalling pathway, or of the strigolactone biosynthetic and signalling pathways. Instead, GAs appear to act by perturbing polar auxin transport, in particular auxin efflux in hybrid aspen, and both efflux and influx in Arabidopsis. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

  3. Light requirement for shoot regeneration in horseradish hairy roots.

    Science.gov (United States)

    Saitou, T; Kamada, H; Harada, H

    1992-08-01

    Hairy roots of horseradish (Armoracia rusticana) were induced by inoculation with Agrobacterium rhizogenes harboring Ri plasmid and cultured on phytohormone-free Murashige and Skoog medium after eliminating the bacteria. Hairy roots grew vigorously and sometimes formed yellowish calli under dark conditions. On the other hand, growth of hairy roots stopped after several weeks of culture with light, then shoots were regenerated. Frequency of shoot formation from hairy roots increased as the culture period in light lengthened and the light intensity increased. The shoot regeneration was induced by treatment with white or red light, but not with far-red light. Shoot regeneration by red light was inhibited by following treatment with far-red light. Red and far-red light reversibly affected shoot regeneration. Excised roots of nontransformed plants grew quite slowly on phytohormone-free Murashige and Skoog medium and occasionally formed shoots under white light conditions.

  4. Growth and microtubule orientation of Zea mays roots subjected to osmotic stress

    Science.gov (United States)

    Blancaflor, E. B.; Hasenstein, K. H.

    1995-01-01

    Previous work has shown that microtubule (MT) reorientation follows the onset of growth inhibition on the lower side of graviresponding roots, indicating that growth reduction can occur independently of MT reorientation. To test this observation further, we examined whether the reduction in growth in response to osmotic stress is correlated with MT reorientation. The distribution and rate of growth in maize roots exposed to 350 mOsm sorbitol and KCl or 5 mM Mes/Tris buffer were measured with a digitizer. After various times roots were processed for indirect immunofluorescence microscopy. Application of sorbitol or KCl had no effect on the organization of MTs in the apical 2 mm of the root but resulted in striking and different effects in the basal region of the root. Sorbitol treatment caused rapid appearance of oval to circular holes in the microtubular array that persisted for at least 9 h. Between 30 min and 4 h of submersion in KCl, MTs in cortical cells 4 mm and farther from the quiescent center began to reorient oblique to the longitudinal axis. After 9 h, the alignment of MTs had shifted to parallel to the root axis but MTs of the epidermal cells remained transverse. In KCl-treated roots MT reorientation appeared to follow a pattern of development similar to that in controls but without elongation. Our data provide additional evidence that MT reorientation is not the cause but a consequence of growth inhibition.

  5. Characterisation of bacteria from Pinus sylvestris-Suillus luteus mycorrhizas and their effects on root-fungus interactions and plant growth.

    Science.gov (United States)

    Bending, Gary D; Poole, Elizabeth J; Whipps, John M; Read, David J

    2002-03-01

    Bacteria from Pinus sylvestris-Suillus luteus mycorrhizas were isolated, characterised, and their effects on P. sylvestris-S. luteus interactions and plant growth investigated in vitro. The isolates formed five distinct phenotypic and physiological groups. Two of the groups, accounting for 34 of the 55 isolates, consisted of Bacillus spp., with three subgroups represented. The other groups contained Burkholderia spp., Serratia spp. and Pseudomonas spp. Representatives from each bacterial group were used in microcosm experiments to investigate bacterial effects on P. sylvestris-S. luteus interactions. Most Bacillus isolates stimulated growth of S. luteus along the P. sylvestris root, while isolates of Pseudomonas and Serratia inhibited root colonisation by the fungus. Burkholderia and Serratia isolates inhibited ectomycorrhiza formation by 97 and 41% respectively, while a single Bacillus isolate doubled the formation of first order ectomycorrhizal roots. There were no clear relationships between effects of the bacteria on root colonisation by the fungus after 4 weeks, and chitinase production or subsequent ectomycorrhiza formation. However, isolates that inhibited ectomycorrhiza formation appeared to associate preferentially with ectomycorrhizal roots. Several isolates enhanced plant growth substantially, although these effects were unrelated to either root colonisation by the fungus or ectomycorrhiza formation.

  6. Novel MtCEP1 peptides produced in vivo differentially regulate root development in Medicago truncatula.

    Science.gov (United States)

    Mohd-Radzman, Nadiatul A; Binos, Steve; Truong, Thy T; Imin, Nijat; Mariani, Michael; Djordjevic, Michael A

    2015-08-01

    Small, post-translationally modified and secreted peptides regulate diverse plant developmental processes. Due to low natural abundance, it is difficult to isolate and identify these peptides. Using an improved peptide isolation protocol and Orbitrap mass spectrometry, nine 15-amino-acid CEP peptides were identified that corresponded to the two domains encoded by Medicago truncatula CEP1 (MtCEP1). Novel arabinosylated and hydroxylated peptides were identified in root cultures overexpressing MtCEP1. The five most abundant CEP peptides were hydroxylated and these species were detected also in low amounts in vector control samples. Synthetic peptides with different hydroxylation patterns differentially affected root development. Notably, the domain 1 peptide hydroxylated at Pro4 and Pro11 (D1:HyP4,11) imparted the strongest inhibition of lateral root emergence when grown with 5mM KNO3 and stimulated the highest increase in nodule number when grown with 0mM KNO3. Inhibition of lateral root emergence by D1:HyP4,11 was not alleviated by removing peptide exposure. In contrast, the domain 2 peptide hydroxylated at Pro11 (D2:HyP11) increased stage III-IV lateral root primordium numbers by 6-fold (P emerge. Auxin addition at levels which stimulated lateral root formation in wild-type plants had little or no ameliorating effect on CEP peptide-mediated inhibition of lateral root formation or emergence. Both peptides increased and altered the root staining pattern of the auxin-responsive reporter GH3:GUS suggesting CEPs alter auxin sensitivity or distribution. The results showed that CEP primary sequence and post-translational modifications influence peptide activities and the improved isolation procedure effectively and reproducibly identifies and characterises CEPs. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  7. Growth and Anatomical Parameters of Adventitious Roots Formed on Mung Bean Hypocotyls Are Correlated with Galactoglucomannan Oligosaccharides Structure

    Directory of Open Access Journals (Sweden)

    K. Kollárová

    2012-01-01

    Full Text Available The effect of galactoglucomannan oligosaccharides (GGMOs compared with chemically modified oligosaccharides, GGMOs-g (with reduced number of D-galactose side chains and GGMOs-r (with reduced reducing ends on mung bean (Vigna radiata (L. Wilczek adventitious roots formation, elongation, and anatomical structure have been studied. All types of oligosaccharides influenced adventitious root formation in the same way: stimulation in the absence of exogenous auxin and inhibition in the presence of exogenous auxin. Both reactions are probably related with the presence/content of endogenous auxin in plant cuttings. However, the adventitious root length was inhibited by GGMOs both in the absence as well as in the presence of auxin (IBA or NAA, while GGMOs-g inhibition was significantly weaker compared with GGMOs. GGMOs-r were without significant difference on both processes, compared with GGMOs. GGMOs affected not only the adventitious root length but also their anatomy in dependence on the combination with certain type of auxin. The oligosaccharides influenced cortical cells division, which was reflected in the cortex area and in the root diameter. All processes followed were dependent on oligosaccharides chemical structure. The results suggest also that GGM-derived oligosaccharides may play an important role in adventitious roots elongation but not in their formation.

  8. The use of 32P to study root growth of soybean as affected by soil compaction

    International Nuclear Information System (INIS)

    Sisworo, Elsje L.; Sisworo, Widjang H.; Syaukat, Sri Harti; Wemay, Johannis; Haryanto

    1996-01-01

    Two greenhouse and two field experiments have been conducted to study the effect of soil compaction on root and plant growth of soybean, by using 32 P in the form of carrier free KH 2 32 PO 4 solution. In the greenhouse experiment it was clearly shown that by increasing soil compaction the growth of roots and shoots was increasingly inhibited. The growth of roots was expressed in √% arcsin converted from 32 P activity (counts per minute, cpm) in the shoots and 32 P activity in the shoots (cpm) without convertion. Plant growth was expressed in plant height, number of leaves, dry weight of pods and shoots. In the field experiment, it was shown distinctively that root growth in the 15 cm soil depth was inhibited whith the increase of soil compaction. Similar with the greenhouse experiments the of plants of roots was expressed in cpm 32 P of roots, shoots, and pods, while, the growth of plants was expressed in plant height, number of pods, and dry weight of pods, seeds, and stover. (author). 19 refs, 4 tabs, 6 figs

  9. Plasma membrane NADH oxidase of maize roots responds to gravity and imposed centrifugal forces

    Science.gov (United States)

    Bacon, E.; Morre, D. J.

    2001-01-01

    NADH oxidase activities measured with excised roots of dark-grown maize (Zea mays) seedlings and with isolated plasma membrane vesicles from roots of dark-grown maize oscillated with a regular period length of 24 min and were inhibited by the synthetic auxin 2,4-dichlorophenoxyacetic [correction of dichorophenoxyacetic] acid. The activities also responded to orientation with respect to gravity and to imposed centrifugal forces. Turning the roots upside down resulted in stimulation of the activity with a lag of about 10 min. Returning the sections to the normal upright position resulted in a return to initial rates. The activity was stimulated reversibly to a maximum of about 2-fold with isolated plasma membrane vesicles, when subjected to centrifugal forces of 25 to 250 x g for 1 to 4 min duration. These findings are the first report of a gravity-responsive enzymatic activity of plant roots inhibited by auxin and potentially related to the gravity-induced growth response. c2001 Editions scientifiques et medicales Elsevier SAS.

  10. Aluminium localization and toxicity symptoms related to root growth ...

    Indian Academy of Sciences (India)

    2012-10-26

    Oct 26, 2012 ... Aluminium localization and toxicity symptoms related to root growth inhibition in rice (Oryza sativa ... growth of this cultivar when submitted to Al3+ stress. Moreover ..... Caiapó. Previous work has shown the IAC cultivar to be.

  11. EXPANSINA17 up-regulated by LBD18/ASL20 promotes lateral root formation during the auxin response.

    Science.gov (United States)

    Lee, Han Woo; Kim, Jungmook

    2013-10-01

    Expansins are non-hydrolytic cell wall-loosening proteins involved in a variety of plant developmental processes during which cell wall modification occurs. Cell wall remodeling proteins including expansins have been suggested to be involved in cell separation to facilitate the emergence of lateral roots (LRs) through the overlaying tissues of the primary root. LBD18/ASL20 activates EXPANSINA14 (EXPA14) expression by directly binding to the EXPA14 promoter to enhance LR emergence in Arabidopsis thaliana. Here we show that EXPA17 is another target gene regulated by LBD18 to promote LR formation in Arabidopsis. We showed that nuclear translocation of the LBD18:GR fusion protein expressed under the Cauliflower mosaic virus (CaMV) 35S promoter or under the LBD18 promoter by dexamethasone treatment results in an increase in EXPA17 transcript levels. β-Glucuronidase (GUS) expression under the EXPA17 promoter, which is detected only in the roots of the wild type, was reduced in the LR primordium and overlaying tissues in an lbd18 mutant background. The number of emerged LRs of the EXPA17 RNAi (RNA interference) Arabidopsis lines was significantly lower than that of the wild type. Overexpression of EXPA17 in Arabidopsis increased the density of emerged LRs in the presence of auxin compared with the wild type. LR induction experiments with a gravitropic stimulus showed that LR emergence is delayed in the EXPA17 RNAi plants compared with the wild type. In addition, EXPA4 expression was also detected in overlaying tissues of the LR primordium and was inducible by LBD18. Taken together, these results support the notion that LBD18 up-regulates a subset of EXP genes to enhance cell separation to promote LR emergence in Arabidopsis.

  12. 4,4,4-trifluoro-3-(indole-3-)butyric acid promotes root elongation in Lactuca sativa independent of ethylene synthesis and pH

    Science.gov (United States)

    Zhang, Nenggang; Hasenstein, Karl H.

    2002-01-01

    We studied the mode of action of 4,4,4-trifluoro-3- (indole-3-) butyric acid (TFIBA), a recently described root growth stimulator, on primary root growth of Lactuca sativa L. seedlings. TFIBA (100 micromoles) promoted elongation of primary roots by 40% in 72 h but inhibited hypocotyl growth by 35%. TFIBA induced root growth was independent of pH. TFIBA did not affect ethylene production, but reduced the inhibitory effect of ethylene on root elongation. TFIBA promoted root growth even in the presence of the ethylene biosynthesis inhibitor L-alpha-(2-aminoethoxyvinyl)glycine. TFIBA and the ethylene-binding inhibitor silver thiosulphate (STS) had a similar effect on root elongation. The results indicate that TFIBA-stimulated root elongation was neither pH-dependent nor related to inhibition of ethylene synthesis, but was possibly related to ethylene action.

  13. Phytochemical and Antibacterial Properties of Root and Leaf ...

    African Journals Online (AJOL)

    Antibacterial growth inhibition was determined using Ditch method against ... have examined the effects of plants used traditionally ... and 16 cm wide (Aliyu, 2006). .... India. Likewise, water extracts obtained from the root did not show activity on all the test organisms except .... toxicity studies of Parkinsonia aculeate L.

  14. 1,8-cineole inhibits both proliferation and elongation of BY-2 cultured tobacco cells.

    Science.gov (United States)

    Yoshimura, Hiroko; Sawai, Yu; Tamotsu, Satoshi; Sakai, Atsushi

    2011-03-01

    Volatile monoterpenes such as 1,8-cineole inhibit the growth of Brassica campestris seedlings in a dose-dependent manner, and the growth-inhibitory effects are more severe for roots than hypocotyls. The preferential inhibition of root growth may be explained if the compounds inhibit cell proliferation more severely than cell elongation because root growth requires both elongation and proliferation of the constituent cells, whereas hypocotyl growth depends exclusively on elongation of existing cells. In order to examine this possibility, BY-2 suspension-cultured tobacco (Nicotiana tabacum) cells were treated with 1,8-cineole, and the inhibitory effects on cell proliferation and on cell elongation were assessed quantitatively. Treatment with 1,8-cineole lowered both the mitotic index and elongation of the cells in a dose-dependent manner, and the half-maximal inhibitory concentration (IC₅₀) for cell elongation was lower than that for cell proliferation. Moreover, 1,8-cineole also inhibited starch synthesis, with IC₅₀ lower than that for cell proliferation. Thus, the inhibitory effects of 1,8-cineole were not specific to cell proliferation; rather, 1,8-cineole seemed inhibitory to a variety of physiological activities when it was in direct contact with target cells. Based on these results, possible mechanisms for the mode of action of 1,8-cineole and for its preferential inhibition on root growth are discussed.

  15. Growth and graviresponsiveness of primary roots of Zea mays seedlings deficient in abscisic acid and gibberellic acid

    Science.gov (United States)

    Moore, R.; Dickey, K.

    1985-01-01

    The objective of this research was to determine if gibberellic acid (GA) and/or abscisic acid (ABA) are necessary for graviresponsiveness by primary roots of Zea mays. To accomplish this objective we measured the growth and graviresponsiveness of primary roots of seedlings in which the synthesis of ABA and GA was inhibited collectively and individually by genetic and chemical means. Roots of seedlings treated with Fluridone (an inhibitor of ABA biosynthesis) and Ancymidol (an inhibitor of GA biosynthesis) were characterized by slower growth rates but not significantly different gravicultures as compared to untreated controls. Gravicurvatures of primary roots of d-5 mutants (having undetectable levels of GA) and vp-9 mutants (having undectable levels of ABA) were not significantly different from those of wild-type seedlings. Roots of seedlings in which the biosynthesis of ABA and GA was collectively inhibited were characterized by gravicurvatures not significantly different for those of controls. These results (1) indicate that drastic reductions in the amount of ABA and GA in Z. mays seedlings do not significantly alter root graviresponsiveness, (2) suggest that neither ABA nor GA is necessary for root gravicurvature, and (3) indicate that root gravicurvature is not necessarily proportional to root elongation.

  16. Early Arabidopsis root hair growth stimulation by pathogenic strains of Pseudomonas syringae.

    Science.gov (United States)

    Pecenková, Tamara; Janda, Martin; Ortmannová, Jitka; Hajná, Vladimíra; Stehlíková, Zuzana; Žárský, Viktor

    2017-09-01

    Selected beneficial Pseudomonas spp. strains have the ability to influence root architecture in Arabidopsis thaliana by inhibiting primary root elongation and promoting lateral root and root hair formation. A crucial role for auxin in this long-term (1week), long-distance plant-microbe interaction has been demonstrated. Arabidopsis seedlings were cultivated in vitro on vertical plates and inoculated with pathogenic strains Pseudomonas syringae pv. maculicola (Psm) and P. syringae pv. tomato DC3000 (Pst), as well as Agrobacterium tumefaciens (Atu) and Escherichia coli (Eco). Root hair lengths were measured after 24 and 48h of direct exposure to each bacterial strain. Several Arabidopsis mutants with impaired responses to pathogens, impaired ethylene perception and defects in the exocyst vesicle tethering complex that is involved in secretion were also analysed. Arabidopsis seedling roots infected with Psm or Pst responded similarly to when infected with plant growth-promoting rhizobacteria; root hair growth was stimulated and primary root growth was inhibited. Other plant- and soil-adapted bacteria induced similar root hair responses. The most compromised root hair growth stimulation response was found for the knockout mutants exo70A1 and ein2. The single immune pathways dependent on salicylic acid, jasmonic acid and PAD4 are not directly involved in root hair growth stimulation; however, in the mutual cross-talk with ethylene, they indirectly modify the extent of the stimulation of root hair growth. The Flg22 peptide does not initiate root hair stimulation as intact bacteria do, but pretreatment with Flg22 prior to Psm inoculation abolished root hair growth stimulation in an FLS2 receptor kinase-dependent manner. These early response phenomena are not associated with changes in auxin levels, as monitored with the pDR5::GUS auxin reporter. Early stimulation of root hair growth is an effect of an unidentified component of living plant pathogenic bacteria. The root

  17. Light Requirement for Shoot Regeneration in Horseradish Hairy Roots 1

    Science.gov (United States)

    Saitou, Tsutomu; Kamada, Hiroshi; Harada, Hiroshi

    1992-01-01

    Hairy roots of horseradish (Armoracia rusticana) were induced by inoculation with Agrobacterium rhizogenes harboring Ri plasmid and cultured on phytohormone-free Murashige and Skoog medium after eliminating the bacteria. Hairy roots grew vigorously and sometimes formed yellowish calli under dark conditions. On the other hand, growth of hairy roots stopped after several weeks of culture with light, then shoots were regenerated. Frequency of shoot formation from hairy roots increased as the culture period in light lengthened and the light intensity increased. The shoot regeneration was induced by treatment with white or red light, but not with far-red light. Shoot regeneration by red light was inhibited by following treatment with far-red light. Red and far-red light reversibly affected shoot regeneration. Excised roots of nontransformed plants grew quite slowly on phytohormone-free Murashige and Skoog medium and occasionally formed shoots under white light conditions. PMID:16669041

  18. When stress and development go hand in hand: main hormonal controls of adventitious rooting in cuttings.

    Science.gov (United States)

    da Costa, Cibele T; de Almeida, Márcia R; Ruedell, Carolina M; Schwambach, Joseli; Maraschin, Felipe S; Fett-Neto, Arthur G

    2013-01-01

    Adventitious rooting (AR) is a multifactorial response leading to new roots at the base of stem cuttings, and the establishment of a complete and autonomous plant. AR has two main phases: (a) induction, with a requirement for higher auxin concentration; (b) formation, inhibited by high auxin and in which anatomical changes take place. The first stages of this process in severed organs necessarily include wounding and water stress responses which may trigger hormonal changes that contribute to reprogram target cells that are competent to respond to rooting stimuli. At severance, the roles of jasmonate and abscisic acid are critical for wound response and perhaps sink strength establishment, although their negative roles on the cell cycle may inhibit root induction. Strigolactones may also inhibit AR. A reduced concentration of cytokinins in cuttings results from the separation of the root system, whose tips are a relevant source of these root induction inhibitors. The combined increased accumulation of basipetally transported auxins from the shoot apex at the cutting base is often sufficient for AR in easy-to-root species. The role of peroxidases and phenolic compounds in auxin catabolism may be critical at these early stages right after wounding. The events leading to AR strongly depend on mother plant nutritional status, both in terms of minerals and carbohydrates, as well as on sink establishment at cutting bases. Auxins play a central role in AR. Auxin transporters control auxin canalization to target cells. There, auxins act primarily through selective proteolysis and cell wall loosening, via their receptor proteins TIR1 (transport inhibitor response 1) and ABP1 (Auxin-Binding Protein 1). A complex microRNA circuitry is involved in the control of auxin response factors essential for gene expression in AR. After root establishment, new hormonal controls take place, with auxins being required at lower concentrations for root meristem maintenance and cytokinins

  19. A bell pepper cultivar tolerant to chilling enhanced nitrogen allocation and stress-related metabolite accumulation in the roots in response to low root-zone temperature.

    Science.gov (United States)

    Aidoo, Moses Kwame; Sherman, Tal; Lazarovitch, Naftali; Fait, Aaron; Rachmilevitch, Shimon

    2017-10-01

    Two bell pepper (Capsicum annuum) cultivars, differing in their response to chilling, were exposed to three levels of root-zone temperatures. Gas exchange, shoot and root phenology, and the pattern of change of the central metabolites and secondary metabolites caffeate and benzoate in the leaves and roots were profiled. Low root-zone temperature significantly inhibited gaseous exchange, with a greater effect on the sensitive commercial pepper hybrid (Canon) than on the new hybrid bred to enhance abiotic stress tolerance (S103). The latter was less affected by the treatment with respect to plant height, shoot dry mass, root maximum length, root projected area, number of root tips and root dry mass. More carbon was allocated to the leaves of S103 than nitrogen at 17°C, while in the roots at 17°C, more nitrogen was allocated and the ratio between C/N decreased. Metabolite profiling showed greater increase in the root than in the leaves. Leaf response between the two cultivars differed significantly. The roots accumulated stress-related metabolites including γ-aminobutyric acid (GABA), proline, galactinol and raffinose and at chilling (7°C) resulted in an increase of sugars in both cultivars. Our results suggest that the enhanced tolerance of S103 to root cold stress, reflected in the relative maintenance of shoot and root growth, is likely linked to a more effective regulation of photosynthesis facilitated by the induction of stress-related metabolism. © 2017 Scandinavian Plant Physiology Society.

  20. Abscisic Acid Stimulates Elongation of Excised Pea Root Tips

    Science.gov (United States)

    Gaither, Douglas H.; Lutz, Donald H.; Forrence, Leonard E.

    1975-01-01

    Excised Pisum sativum L. root tips were incubated in a pH 5.2 sucrose medium containing abscisic acid. Elongation growth was inhibited by 100 μm abscisic acid. However, decreasing the abscisic acid concentration caused stimulation of elongation, the maximum response (25% to 30%) occurring at 1 μm abscisic acid. Prior to two hours, stimulation of elongation by 1 μm abscisic acid was not detectable. Increased elongation did not occur in abscisic acid-treated root tips of Lens culinaris L., Phaseolus vulgaris L., or Zea mays L. PMID:16659198

  1. Strigolactones Suppress Adventitious Rooting in Arabidopsis and Pea1[C][W][OA

    Science.gov (United States)

    Rasmussen, Amanda; Mason, Michael Glenn; De Cuyper, Carolien; Brewer, Philip B.; Herold, Silvia; Agusti, Javier; Geelen, Danny; Greb, Thomas; Goormachtig, Sofie; Beeckman, Tom; Beveridge, Christine Anne

    2012-01-01

    Adventitious root formation is essential for the propagation of many commercially important plant species and involves the formation of roots from nonroot tissues such as stems or leaves. Here, we demonstrate that the plant hormone strigolactone suppresses adventitious root formation in Arabidopsis (Arabidopsis thaliana) and pea (Pisum sativum). Strigolactone-deficient and response mutants of both species have enhanced adventitious rooting. CYCLIN B1 expression, an early marker for the initiation of adventitious root primordia in Arabidopsis, is enhanced in more axillary growth2 (max2), a strigolactone response mutant, suggesting that strigolactones restrain the number of adventitious roots by inhibiting the very first formative divisions of the founder cells. Strigolactones and cytokinins appear to act independently to suppress adventitious rooting, as cytokinin mutants are strigolactone responsive and strigolactone mutants are cytokinin responsive. In contrast, the interaction between the strigolactone and auxin signaling pathways in regulating adventitious rooting appears to be more complex. Strigolactone can at least partially revert the stimulatory effect of auxin on adventitious rooting, and auxin can further increase the number of adventitious roots in max mutants. We present a model depicting the interaction of strigolactones, cytokinins, and auxin in regulating adventitious root formation. PMID:22323776

  2. Hormonal control of root development on epiphyllous plantlets of Bryophyllum (Kalanchoe) marnierianum: role of auxin and ethylene.

    Science.gov (United States)

    Kulka, Richard G

    2008-01-01

    Epiphyllous plantlets develop on leaves of Bryophyllum marnierianum when they are excised from the plant. Shortly after leaf excision, plantlet shoots develop from primordia located near the leaf margin. After the shoots have enlarged for several days, roots appear at their base. In this investigation, factors regulating plantlet root development were studied. The auxin transport inhibitor 2,3,5-triiodobenzoic acid (TIBA) abolished root formation without markedly affecting shoot growth. This suggested that auxin transport from the plantlet shoot induces root development. Excision of plantlet apical buds inhibits root development. Application of indole-3-acetic acid (IAA) in lanolin at the site of the apical buds restores root outgrowth. Naphthalene acetic acid (NAA), a synthetic auxin, reverses TIBA inhibition of plantlet root emergence on leaf explants. Both of these observations support the hypothesis that auxin, produced by the plantlet, induces root development. Exogenous ethylene causes precocious root development several days before that of a control without hormone. Ethylene treatment cannot bypass the TIBA block of root formation. Therefore, ethylene does not act downstream of auxin in root induction. However, ethylene amplifies the effects of low concentrations of NAA, which in the absence of ethylene do not induce roots. Ag(2)S(2)O(3), an ethylene blocker, and CoCl(2), an ethylene synthesis inhibitor, do not abolish plantlet root development. It is therefore unlikely that ethylene is essential for root formation. Taken together, the experiments suggest that roots develop when auxin transport from the shoot reaches a certain threshold. Ethylene may augment this effect by lowering the threshold and may come into play when the parent leaf senesces.

  3. Automated Root Tracking with "Root System Analyzer"

    Science.gov (United States)

    Schnepf, Andrea; Jin, Meina; Ockert, Charlotte; Bol, Roland; Leitner, Daniel

    2015-04-01

    Crucial factors for plant development are water and nutrient availability in soils. Thus, root architecture is a main aspect of plant productivity and needs to be accurately considered when describing root processes. Images of root architecture contain a huge amount of information, and image analysis helps to recover parameters describing certain root architectural and morphological traits. The majority of imaging systems for root systems are designed for two-dimensional images, such as RootReader2, GiA Roots, SmartRoot, EZ-Rhizo, and Growscreen, but most of them are semi-automated and involve mouse-clicks in each root by the user. "Root System Analyzer" is a new, fully automated approach for recovering root architectural parameters from two-dimensional images of root systems. Individual roots can still be corrected manually in a user interface if required. The algorithm starts with a sequence of segmented two-dimensional images showing the dynamic development of a root system. For each image, morphological operators are used for skeletonization. Based on this, a graph representation of the root system is created. A dynamic root architecture model helps to determine which edges of the graph belong to an individual root. The algorithm elongates each root at the root tip and simulates growth confined within the already existing graph representation. The increment of root elongation is calculated assuming constant growth. For each root, the algorithm finds all possible paths and elongates the root in the direction of the optimal path. In this way, each edge of the graph is assigned to one or more coherent roots. Image sequences of root systems are handled in such a way that the previous image is used as a starting point for the current image. The algorithm is implemented in a set of Matlab m-files. Output of Root System Analyzer is a data structure that includes for each root an identification number, the branching order, the time of emergence, the parent

  4. Inhibition of aldose reductase by Gentiana lutea extracts.

    Science.gov (United States)

    Akileshwari, Chandrasekhar; Muthenna, Puppala; Nastasijević, Branislav; Joksić, Gordana; Petrash, J Mark; Reddy, Geereddy Bhanuprakash

    2012-01-01

    Accumulation of intracellular sorbitol due to increased aldose reductase (ALR2) activity has been implicated in the development of various secondary complications of diabetes. Thus, ALR2 inhibition could be an effective strategy in the prevention or delay of certain diabetic complications. Gentiana lutea grows naturally in the central and southern areas of Europe. Its roots are commonly consumed as a beverage in some European countries and are also known to have medicinal properties. The water, ethanol, methanol, and ether extracts of the roots of G. lutea were subjected to in vitro bioassay to evaluate their inhibitory activity on the ALR2. While the ether and methanol extracts showed greater inhibitory activities against both rat lens and human ALR2, the water and ethanol extracts showed moderate inhibitory activities. Moreover, the ether and methanol extracts of G. lutea roots significantly and dose-dependently inhibited sorbitol accumulation in human erythrocytes under high glucose conditions. Molecular docking studies with the constituents commonly present in the roots of G. lutea indicate that a secoiridoid glycoside, amarogentin, may be a potential inhibitor of ALR2. This is the first paper that shows G. lutea extracts exhibit inhibitory activity towards ALR2 and these results suggest that Gentiana or its constituents might be useful to prevent or treat diabetic complications.

  5. CLE peptides regulate lateral root development in response to nitrogen nutritional status of plants.

    Science.gov (United States)

    Araya, Takao; von Wirén, Nicolaus; Takahashi, Hideki

    2014-01-01

    CLE (CLAVATA3/embryo surrounding region (ESR)) peptides control meristem functions in plants. Our recent study highlights the critical role of a peptide-receptor signaling module composed of nitrogen (N)-responsive CLE peptides and the CLAVATA1 (CLV1) leucine-rich repeat receptor-like kinase in controlling lateral root development in Arabidopsis thaliana. CLE1, -3, -4 and -7 are expressed in root pericycle cells in Arabidopsis roots under N-limited growth conditions. Overexpression of these CLE genes inhibits lateral root emergence from the primary root. The inhibitory action of N-responsive CLE peptides on lateral root development requires the function of CLV1 expressed in phloem companion cells in roots, suggesting that downstream signals are transferred through phloem for systemic regulation of root system architecture. An additional mechanism downstream of CLV1 feedback-regulates transcript levels of N-responsive CLE genes in roots for fine-tuning the signal amplitude.

  6. The effect of CO2 laser irradiation plus fluoride dentifrice on the inhibition of secondary caries on root surfaces adjacent to glass ionomer cement or composite resin restorations

    International Nuclear Information System (INIS)

    Rodrigues, S R; Moraes, M; Youssef, M N; De Souza-Zaroni, W C; Hanashiro, F S; Brugnera Junior, A; Nobre-dos-Santos, M

    2016-01-01

    Although the cariostatic effects of CO 2 laser on the root surface have been shown, there is scarce information regarding its effects on root secondary caries. The objective of this research was to investigate the effect of the association of CO 2 laser and a fluoride dentifrice on the inhibition of secondary caries on root surfaces adjacent to composite-resin or glass-ionomer-cement restorations. Dental blocks of human roots were divided into two groups: composite resin (CR) or glass ionomer cement (GIC). Subsequently, the blocks were divided into four subgroups (n  =  10): C, non-fluoride dentifrice; FD, fluoride dentifrice; L, CO 2 laser with an energy density of 6.0 J cm −2   +  non-fluoride dentifrice; and L  +  FD, CO 2 laser  +  fluoride dentifrice. The blocks were subjected to pH cycling to simulate a high cariogenic challenge. Dental demineralization around the restorations was quantified by microhardness analysis. The results were subjected to analysis of variance (ANOVA) and the Tukey–Kramer test (p  ⩽  0.05). As for mineral loss, it can be observed that all the groups that were treated with a fluoride dentifrice and laser, used alone or not, were statistically similar and superior to the RC–C group. It was concluded that CO 2 laser irradiation and a fluoride dentifrice used alone or combined with each other are efficient surface treatments for preventing secondary root caries, regardless of the restorative material used. (paper)

  7. Phytotoxic cyanamide affects maize (Zea mays) root growth and root tip function: from structure to gene expression.

    Science.gov (United States)

    Soltys, Dorota; Rudzińska-Langwald, Anna; Kurek, Wojciech; Szajko, Katarzyna; Sliwinska, Elwira; Bogatek, Renata; Gniazdowska, Agnieszka

    2014-05-01

    Cyanamide (CA) is a phytotoxic compound produced by four Fabaceae species: hairy vetch, bird vetch, purple vetch and black locust. Its toxicity is due to complex activity that involves the modification of both cellular structures and physiological processes. To date, CA has been investigated mainly in dicot plants. The goal of this study was to investigate the effects of CA in the restriction of the root growth of maize (Zea mays), representing the monocot species. CA (3mM) reduced the number of border cells in the root tips of maize seedlings and degraded their protoplasts. However, CA did not induce any significant changes in the organelle structure of other root cells, apart from increased vacuolization. CA toxicity was also demonstrated by its effect on cell cycle activity, endoreduplication intensity, and modifications of cyclins CycA2, CycD2, and histone HisH3 gene expression. In contrast, the arrangement of microtubules was not altered by CA. Treatment of maize seedlings with CA did not completely arrest mitotic activity, although the frequency of dividing cells was reduced. Furthermore, prolonged CA treatment increased the proportion of endopolyploid cells in the root tip. Cytological malformations were accompanied by an induction of oxidative stress in root cells, which manifested as enhanced accumulation of H2O2. Exposure of maize seedlings to CA resulted in an increased concentration of auxin and stimulated ethylene emission. Taken together, these findings suggested that the inhibition of root growth by CA may be a consequence of stress-induced morphogenic responses. Copyright © 2014. Published by Elsevier GmbH.

  8. Cadmium induces changes in sucrose partitioning, invertase activities, and membrane functionality in roots of Rangpur lime (Citrus limonia L. Osbeck).

    Science.gov (United States)

    Podazza, G; Rosa, M; González, J A; Hilal, M; Prado, F E

    2006-09-01

    Cadmium (Cd) uptake effects on sucrose content, invertase activities, and plasma membrane functionality were investigated in Rangpur lime roots ( CITRUS LIMONIA L. Osbeck). Cadmium accumulation was significant in roots but not in shoots and leaves. Cadmium produced significant reduction in roots DW and increment in WC. Leaves and shoots did not show significant differences on both parameters. Sucrose content was higher in control roots than in Cd-exposed ones. Apoplastic sucrose content was much higher in Cd-exposed roots than in control ones. Cd-exposed roots showed a significant decrease in both cell wall-bound and cytoplasmic (neutral) invertase activities; while the vacuolar isoform did not show any change. Alterations in lipid composition and membrane fluidity of Cd-exposed roots were also observed. In Cd-exposed roots phospholipid and glycolipid contents decreased about 50 %, while sterols content was reduced about 22 %. Proton extrusion was inhibited by Cd. Lipid peroxidation and proton extrusion inhibition were also detected by histochemical analysis. This work's findings demonstrate that Cd affects sucrose partitioning and invertase activities in apoplastic and symplastic regions in Rangpur lime roots as well as the plasma membrane functionality and H (+)-ATPase activity.

  9. Avocado roots treated with salicylic acid produce phenol-2,4-bis (1,1-dimethylethyl), a compound with antifungal activity.

    Science.gov (United States)

    Rangel-Sánchez, Gerardo; Castro-Mercado, Elda; García-Pineda, Ernesto

    2014-02-15

    We demonstrated the ability of salicylic acid (SA) to induce a compound in avocado roots that strengthens their defense against Phytophthora cinnamomi. The SA content of avocado roots, before and after the application of exogenous SA, was determined by High-Performance Liquid Chromatography (HPLC). After 4h of SA feeding, the endogenous level in the roots increased to 223 μg g(-1) FW, which was 15 times the amount found in control roots. The methanolic extract obtained from SA-treated avocado roots inhibited the radial growth of P. cinnamomi. A thin layer chromatographic bioassay with the methanolic extract and spores of Aspergillus showed a distinct inhibition zone. The compound responsible for the inhibition was identified as phenol-2,4-bis (1,1-dimethylethyl) by gas chromatography and mass spectrometry. At a concentration of 100 μg/mL, the substance reduced germinative tube length in Aspergillus and radial growth of P. cinnamomi. A commercial preparation of phenol-2,4-bis (1,1-dimethylethyl) caused the same effects on mycelium morphology and radial growth as our isolate, confirming the presence of this compound in the root extracts. This is the first report of the induction of this compound in plants by SA, and the results suggest that it plays an important role in the defense response of avocado. Copyright © 2013 Elsevier GmbH. All rights reserved.

  10. Phosphate-dependent root system architecture responses to salt stress

    KAUST Repository

    Kawa, Dorota; Julkowska, Magdalena; Montero Sommerfeld, Hector; Horst, Anneliek ter; Haring, Michel A; Testerink, Christa

    2016-01-01

    Nutrient availability and salinity of the soil affect growth and development of plant roots. Here, we describe how phosphate availability affects root system architecture (RSA) of Arabidopsis and how phosphate levels modulate responses of the root to salt stress. Phosphate (Pi) starvation reduced main root length and increased the number of lateral roots of Arabidopsis Col-0 seedlings. In combination with salt, low Pi dampened the inhibiting effect of mild salt stress (75mM) on all measured RSA components. At higher NaCl concentrations, the Pi deprivation response prevailed over the salt stress only for lateral root elongation. The Pi deprivation response of lateral roots appeared to be oppositely affected by abscisic acid (ABA) signaling compared to the salt stress response. Natural variation in the response to the combination treatment of salt and Pi starvation within 330 Arabidopsis accessions could be grouped into four response patterns. When exposed to double stress, in general lateral roots prioritized responses to salt, while the effect on main root traits was additive. Interestingly, these patterns were not identical for all accessions studied and multiple strategies to integrate the signals from Pi deprivation and salinity were identified. By Genome Wide Association Mapping (GWAS) 13 genomic loci were identified as putative factors integrating responses to salt stress and Pi starvation. From our experiments, we conclude that Pi starvation interferes with salt responses mainly at the level of lateral roots and that large natural variation exists in the available genetic repertoire of accessions to handle the combination of stresses.

  11. Phosphate-dependent root system architecture responses to salt stress

    KAUST Repository

    Kawa, Dorota

    2016-05-20

    Nutrient availability and salinity of the soil affect growth and development of plant roots. Here, we describe how phosphate availability affects root system architecture (RSA) of Arabidopsis and how phosphate levels modulate responses of the root to salt stress. Phosphate (Pi) starvation reduced main root length and increased the number of lateral roots of Arabidopsis Col-0 seedlings. In combination with salt, low Pi dampened the inhibiting effect of mild salt stress (75mM) on all measured RSA components. At higher NaCl concentrations, the Pi deprivation response prevailed over the salt stress only for lateral root elongation. The Pi deprivation response of lateral roots appeared to be oppositely affected by abscisic acid (ABA) signaling compared to the salt stress response. Natural variation in the response to the combination treatment of salt and Pi starvation within 330 Arabidopsis accessions could be grouped into four response patterns. When exposed to double stress, in general lateral roots prioritized responses to salt, while the effect on main root traits was additive. Interestingly, these patterns were not identical for all accessions studied and multiple strategies to integrate the signals from Pi deprivation and salinity were identified. By Genome Wide Association Mapping (GWAS) 13 genomic loci were identified as putative factors integrating responses to salt stress and Pi starvation. From our experiments, we conclude that Pi starvation interferes with salt responses mainly at the level of lateral roots and that large natural variation exists in the available genetic repertoire of accessions to handle the combination of stresses.

  12. Inhibition effect of calcium hydroxide point and chlorhexidine point on root canal bacteria of necrosis teeth

    Directory of Open Access Journals (Sweden)

    Andry Leonard Je

    2006-03-01

    Full Text Available Calcium Hydroxide point and Chlorhexidine point are new drugs for eliminating bacteria in the root canal. The points slowly and controly realease Calcium Hydroxide and Chlorhexidine into root canal. The purpose of the study was to determined the effectivity of Calcium hydroxide point (Calcium hydroxide plus point and Chlorhexidine point in eleminating the root canal bacteria of nescrosis teeth. In this study 14 subjects were divided into 2 groups. The first group was treated with Calcium hydroxide point and the second was treated with Chlorhexidine poin. The bacteriological sampling were measured with spectrofotometry. The Paired T Test analysis (before and after showed significant difference between the first and second group. The Independent T Test which analysed the effectivity of both groups had not showed significant difference. Although there was no significant difference in statistical test, the result of second group eliminate more bacteria than the first group. The present finding indicated that the use of Chlorhexidine point was better than Calcium hydroxide point in seven days period. The conclusion is Chlorhexidine point and Calcium hydroxide point as root canal medicament effectively eliminate root canal bacteria of necrosis teeth.

  13. Immunologically related lectins from stems and roots of developing seedlings of Cucurbita ficifolia: purification and some properties of root and stem lectins

    Directory of Open Access Journals (Sweden)

    Irena Lorenc-Kubis

    2014-01-01

    Full Text Available Hemagglutinating activity has been found in acetate extracts from roots and stems of squash seedlings (Cucurbita ficifolia. The hemaglutinating activity changes during seeds germination and seedling development. Dot blot and Western blot techniques have shown that proteins from these vegetative tissues cross-reacted with antibodies raised against endogenous cotyledons lectin CLBa and Con A.Lectins were isolated from stems and roots of 6-day old seedlings by precipitation with ethanol, affinity chromatography on Con A-Sepharose, gel filtration on Bio-gel P100 and separated by electrophoresis on polyacrylamide gel. Three purified lectins (RLA1, RLA2, RLA3 were obtained from roots and four from stems (SLA1, SLA2, SLA3, SLA4. The purified lectins from roots and stems agglutinated all human red blood cells, but sheep erythrocytes were most sensitive to agglutination. The hemagglutination of the root lectins RLA2 and RLA3 was inhibited by a very low concentration of arabinose, while RLA1, of xylose and Ga1NAc. Arabinose and Xylose were also found to be the most effective inhibitors of all stem lectins.

  14. Regulation of Arabidopsis root development by nitrate availability.

    Science.gov (United States)

    Zhang, H; Forde, B G

    2000-01-01

    When the root systems of many plant species are exposed to a localized source of nitrate (NO3- they respond by proliferating their lateral roots to colonize the nutrient-rich zone. This study reviews recent work with Arabidopsis thaliana in which molecular genetic approaches are being used to try to understand the physiological and genetic basis for this response. These studies have led to the conclusion that there are two distinct pathways by which NO3- modulates root branching in Arabidopsis. On the one hand, meristematic activity in lateral root tips is stimulated by direct contact with an enriched source of NO3- (the localized stimulatory effect). On the other, a critical stage in the development of the lateral root (just after its emergence from the primary root) is highly susceptible to inhibition by a systemic signal that is related to the amount of NO3- absorbed by the plant (the systemic inhibitory effect). Evidence has been obtained that the localized stimulatory effect is a direct effect of the NO3- ion itself rather than a nutritional effect. A NO3(-)-inducible MADS-box gene (ANR1) has been identified which encodes a component of the signal transduction pathway linking the external NO3- supply to the increased rate of lateral root elongation. Experiments using auxin-resistant mutants have provided evidence for an overlap between the auxin and NO3- response pathways in the control of lateral root elongation. The systemic inhibitory effect, which does not affect lateral root initiation but delays the activation of the lateral root meristem, appears to be positively correlated with the N status of the plant and is postulated to involve a phloem-mediated signal from the shoot.

  15. Inhibition of vascular smooth muscle cell proliferation by Gentiana lutea root extracts.

    Directory of Open Access Journals (Sweden)

    Rushendhiran Kesavan

    Full Text Available Gentiana lutea belonging to the Gentianaceae family of flowering plants are routinely used in traditional Serbian medicine for their beneficial gastro-intestinal and anti-inflammatory properties. The aim of the study was to determine whether aqueous root extracts of Gentiana lutea consisting of gentiopicroside, gentisin, bellidifolin-8-O-glucoside, demethylbellidifolin-8-O-glucoside, isovitexin, swertiamarin and amarogentin prevents proliferation of aortic smooth muscle cells in response to PDGF-BB. Cell proliferation and cell cycle analysis were performed based on alamar blue assay and propidium iodide labeling respectively. In primary cultures of rat aortic smooth muscle cells (RASMCs, PDGF-BB (20 ng/ml induced a two-fold increase in cell proliferation which was significantly blocked by the root extract (1 mg/ml. The root extract also prevented the S-phase entry of synchronized cells in response to PDGF. Furthermore, PDGF-BB induced ERK1/2 activation and consequent increase in cellular nitric oxide (NO levels were also blocked by the extract. These effects of extract were due to blockade of PDGF-BB induced expression of iNOS, cyclin D1 and proliferating cell nuclear antigen (PCNA. Docking analysis of the extract components on MEK1, the upstream ERK1/2 activating kinase using AutoDock4, indicated a likely binding of isovitexin to the inhibitor binding site of MEK1. Experiments performed with purified isovitexin demonstrated that it successfully blocks PDGF-induced ERK1/2 activation and proliferation of RASMCs in cell culture. Thus, Gentiana lutea can provide novel candidates for prevention and treatment of atherosclerosis.

  16. Inhibition of vascular smooth muscle cell proliferation by Gentiana lutea root extracts.

    Science.gov (United States)

    Kesavan, Rushendhiran; Potunuru, Uma Rani; Nastasijević, Branislav; T, Avaneesh; Joksić, Gordana; Dixit, Madhulika

    2013-01-01

    Gentiana lutea belonging to the Gentianaceae family of flowering plants are routinely used in traditional Serbian medicine for their beneficial gastro-intestinal and anti-inflammatory properties. The aim of the study was to determine whether aqueous root extracts of Gentiana lutea consisting of gentiopicroside, gentisin, bellidifolin-8-O-glucoside, demethylbellidifolin-8-O-glucoside, isovitexin, swertiamarin and amarogentin prevents proliferation of aortic smooth muscle cells in response to PDGF-BB. Cell proliferation and cell cycle analysis were performed based on alamar blue assay and propidium iodide labeling respectively. In primary cultures of rat aortic smooth muscle cells (RASMCs), PDGF-BB (20 ng/ml) induced a two-fold increase in cell proliferation which was significantly blocked by the root extract (1 mg/ml). The root extract also prevented the S-phase entry of synchronized cells in response to PDGF. Furthermore, PDGF-BB induced ERK1/2 activation and consequent increase in cellular nitric oxide (NO) levels were also blocked by the extract. These effects of extract were due to blockade of PDGF-BB induced expression of iNOS, cyclin D1 and proliferating cell nuclear antigen (PCNA). Docking analysis of the extract components on MEK1, the upstream ERK1/2 activating kinase using AutoDock4, indicated a likely binding of isovitexin to the inhibitor binding site of MEK1. Experiments performed with purified isovitexin demonstrated that it successfully blocks PDGF-induced ERK1/2 activation and proliferation of RASMCs in cell culture. Thus, Gentiana lutea can provide novel candidates for prevention and treatment of atherosclerosis.

  17. Root developmental adaptation to phosphate starvation: better safe than sorry.

    Science.gov (United States)

    Péret, Benjamin; Clément, Mathilde; Nussaume, Laurent; Desnos, Thierry

    2011-08-01

    Phosphorus is a crucial component of major organic molecules such as nucleic acids, ATP and membrane phospholipids. It is present in soils in the form of inorganic phosphate (Pi), which has low availability and poor mobility. To cope with Pi limitations, plants have evolved complex adaptive responses that include morphological and physiological modifications. This review describes how the model plant Arabidopsis thaliana adapts its root system architecture to phosphate deficiency through inhibition of primary root growth, increase in lateral root formation and growth and production of root hairs, which all promote topsoil foraging. A better understanding of plant adaptation to low phosphate will open the way to increased phosphorus use efficiency by crops. Such an improvement is needed in order to adjust how we manage limited phosphorus stocks and to reduce the disastrous environmental effects of phosphate fertilizers overuse. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Inhibition of Aldose Reductase by Gentiana lutea Extracts

    Directory of Open Access Journals (Sweden)

    Chandrasekhar Akileshwari

    2012-01-01

    Full Text Available Accumulation of intracellular sorbitol due to increased aldose reductase (ALR2 activity has been implicated in the development of various secondary complications of diabetes. Thus, ALR2 inhibition could be an effective strategy in the prevention or delay of certain diabetic complications. Gentiana lutea grows naturally in the central and southern areas of Europe. Its roots are commonly consumed as a beverage in some European countries and are also known to have medicinal properties. The water, ethanol, methanol, and ether extracts of the roots of G. lutea were subjected to in vitro bioassay to evaluate their inhibitory activity on the ALR2. While the ether and methanol extracts showed greater inhibitory activities against both rat lens and human ALR2, the water and ethanol extracts showed moderate inhibitory activities. Moreover, the ether and methanol extracts of G. lutea roots significantly and dose-dependently inhibited sorbitol accumulation in human erythrocytes under high glucose conditions. Molecular docking studies with the constituents commonly present in the roots of G. lutea indicate that a secoiridoid glycoside, amarogentin, may be a potential inhibitor of ALR2. This is the first paper that shows G. lutea extracts exhibit inhibitory activity towards ALR2 and these results suggest that Gentiana or its constituents might be useful to prevent or treat diabetic complications.

  19. Differential effects of methylmercury on the synthesis of protein species in dorsal root ganglia of the rat

    International Nuclear Information System (INIS)

    Kasama, Hidetaka; Itoh, Kazuo; Omata, Saburo; Sugano, Hiroshi

    1989-01-01

    Dorsal root ganglia from control and methylmercury(MeHg)-treated rats were incubated in vitro with 35 S-methionine and the proteins synthesized were analyzed by two-dimensional electrophoresis. The double labelling method, in which proteins of control dorsal root ganglia labelled in vitro with 3 H-leucine were added to each of the two samples as an internal standard, was used to minimize unavoidable errors arising from the resolving procedure itself. The results obtained showed that the effect of MeHg on the synthesis of proteins in dorsal root ganglia was not uniform for individual protein species in the latent period of MeHg intoxication. Among 200 protein species investigated, 157 showed inhibition of synthesis close to that of the total proteins in the tissue (68% of the control). Among the remaining protein species, 20 showed real stimulation of synthesis, whereas 7 were moderately inhibited and 16 were inhibited more strongly than the total proteins in the tissue. These results suggest that the effect of MeHg on the synthetic rates for protein species in dorsal root ganglia differs with the species, and that unusual elevation or reduction of the synthesis of some protein species caused by MeHg may lead to impairment of normal nerve functions. (orig.)

  20. Uptake and phytotoxicity of the herbicide metsulfuron methyl in corn root tissue in the presence of the safener 1,8-naphthalic anhydride

    International Nuclear Information System (INIS)

    Milhomme, H.; Bastide, J.

    1990-01-01

    Growth of Zea mays L. cv Potro roots was inhibited by the herbicide metsulfuron methyl (MSM) at the lowest concentration tested: 5 nanomoles per liter. Pretreatment of corn seeds with commercial 1,8-naphthalic anhydride (NA) at 1% (w/w) partially reversed MSM-induced root growth inhibition. MSM at a concentration of 52 nanomoles per liter was taken up rapidly by roots and accumulated in the corn tissue to concentrations three times those in the external medium; the safener NA increased MSM uptake up to 48 hours. The protective effect of NA was related to the ability of the safener to increase the metabolism of MSM; ten-fold increases in the metabolic rates of MSM were observed in NA-pretreated corn seedlings grown for 48 hours on 52 nanomolar [ 14 C]MSM solution. DNA synthesis determined by measurement of [ 3 H]thymidine incorporation into DNA was inhibited by root MSM applications; after a 6-hour application period, 13 nanomolar MSM solution reduced DNA synthesis by 64%, and the same reduction was also observed with NA-treated seedlings. Pretreatment of corn seeds with safener NA did not increase the acetolactate synthase activity in the roots and did not change, up to 13 micromoles per liter, the in vitro sensitivity of roots to MSM

  1. In vitro antimycobacterial and antilegionella activity of licochalcone A from Chinese licorice roots

    DEFF Research Database (Denmark)

    Friis-Møller, Alice; Chen, Ming; Fuursted, Kurt

    2002-01-01

    Licochalcone A, extracted and purified from Chinese licorice roots, showed in vitro inhibitory effect on human pathogenic Mycobacteria species and Legionella species. M. tuberculosis, M. bovis and BCG were inhibited by ... resistant to > 20 mg/l Legionella pneumophila (serogroups 1 - 7) and L. bozemanii, L. dumoffii, L. feelei, L. longbeacheae and L. wadsworthii were inhibited by licochalcone A 1 - 4 mg/l, whereas L. gormanii and L. micdadei were inhibited by licochalcone A 500 - 1000 mg/l. These data indicate...

  2. Prostaglandin E 2 (PgE 2 ) Inhibition By Crude Extracts Of Selected ...

    African Journals Online (AJOL)

    This study was undertaken to assess anti-inflammatory activity of crude extracts of Cassine transvaalensis Burtt-Davy, Clerodendrum uncinatum Schinz and Commiphora glandulosa Schinz using COX inhibition assay. Water extract of C. transvaalensis root bark (125mg/ml) exhibited a (90%) PGE2 inhibition in ...

  3. Low Frequency Electroacupuncture Alleviated Spinal Nerve Ligation Induced Mechanical Allodynia by Inhibiting TRPV1 Upregulation in Ipsilateral Undamaged Dorsal Root Ganglia in Rats

    Directory of Open Access Journals (Sweden)

    Yong-Liang Jiang

    2013-01-01

    Full Text Available Neuropathic pain is an intractable problem in clinical practice. Accumulating evidence shows that electroacupuncture (EA with low frequency can effectively relieve neuropathic pain. Transient receptor potential vanilloid type 1 (TRPV1 plays a key role in neuropathic pain. The study aimed to investigate whether neuropathic pain relieved by EA administration correlates with TRPV1 inhibition. Neuropathic pain was induced by right L5 spinal nerve ligation (SNL in rats. 2 Hz EA stimulation was administered. SNL induced mechanical allodynia in ipsilateral hind paw. SNL caused a significant reduction of TRPV1 expression in ipsilateral L5 dorsal root ganglia (DRG, but a significant up-regulation in ipsilateral L4 and L6 DRGs. Calcitonin gene-related peptide (CGRP change was consistent with that of TRPV1. EA alleviated mechanical allodynia, and inhibited TRPV1 and CGRP overexpressions in ipsilateral L4 and L6 DRGs. SNL did not decrease pain threshold of contralateral hind paw, and TRPV1 expression was not changed in contralateral L5 DRG. 0.001, 0.01 mg/kg TRPV1 agonist 6′-IRTX fully blocked EA analgesia in ipsilateral hind paw. 0.01 mg/kg 6′-IRTX also significantly decreased pain threshold of contralateral paw. These results indicated that inhibition of TRPV1 up-regulation in ipsilateral adjacent undamaged DRGs contributed to low frequency EA analgesia for mechanical allodynia induced by spinal nerve ligation.

  4. Inhibition of seed germination by extracts of bitter Hawkesbury watermelon containing cucurbitacin, a feeding stimulant for corn rootworm (Coleoptera: Chrysomelidae).

    Science.gov (United States)

    Martin, Phyllis A W; Blackburn, Michael

    2003-04-01

    Cucurbitacins are feeding stimulants for corn rootworm used in baits to control the adults of this insect pest. Corn rootworm larvae also feed compulsively on cucurbitacins. Cucurbitacins are reported to be gibberellin antagonists that may preclude their use as seed treatments for these soil-dwelling insects. The crude extract of a bitter Hawkesbury watermelon containing cucurbitacin E-glycoside significantly inhibited germination of watermelon, squash, and tomato seeds. Although the germination of corn seed was not significantly inhibited, root elongation was inhibited by crude extracts, but not by high-performance liquid chromatography-purified cucurbitacin E-glycoside. Therefore, the effects of the major components in the bitter watermelon extract (e.g., sugars) on seed germination and root elongation were determined. Pure sugars (glucose and fructose), at concentrations found in watermelon extract, mimicked the inhibition of seed germination and root elongation seen with the crude bitter Hawkesbury watermelon extract. Removal of these sugars may be necessary to use this extract as a bait for corn rootworm larvae as a seed or root treatment.

  5. Periapical inflammation subsequent to coronal inoculation of dog teeth root filled with resilon/epiphany in 1 or 2 treatment sessions with chlorhexidine medication.

    Science.gov (United States)

    Santos, João M; Palma, Paulo J; Ramos, João C; Cabrita, António S; Friedman, Shimon

    2014-06-01

    Therapeutic methods that inhibit microbial ingress into filled root canals are desirable. This in vivo study assessed the inhibition of periapical inflammation subsequent to coronal inoculation in canals medicated with 2% chlorhexidine gel and filled with Resilon/Epiphany (Pentron Clinical Technologies, Wallingford, CT). Six Beagle dogs each had 10 two-rooted premolars treated. In group 1 (n = 36 roots), 1 root/tooth had the canal conditioned with Primer Epiphany, filled with Epiphany sealer and Resilon core in 1 session, and coronally sealed with PhotacFil. In group 2 (n = 36 roots), the second root/tooth had the canal medicated with 2% chlorhexidine gel for 1 week and then filled and coronally sealed as in group 1. After 3 weeks, canals were exposed to the oral environment for 7 days, inoculated with isologous plaque, and coronally sealed. Negative controls treated as groups 1 and 2 remained sealed. Positive controls had canals unfilled and exposed. Seven months after inoculation, dogs were euthanized; jaw blocks processed for histologic examination; and periapical inflammation (PI) recorded as none, mild, or severe. In groups 1 and 2, severe PI occurred in 5 of 65 roots (8%) and mild PI in 18 of 65 roots (28%) with a significantly higher (P = .031) PI incidence in group 2 than in group 1. Negative controls had only mild PI in 9 of 29 roots (31%). Roots medicated with 2% chlorhexidine gel had mild PI significantly more (P = .009) than roots filled in 1 session (more than 2-fold). Intracanal medication with 2% chlorhexidine gel and root filling with Resilon/Epiphany did not effectively inhibit apical periodontitis subsequent to coronal inoculation. Copyright © 2014 American Association of Endodontists. All rights reserved.

  6. Growth of bean and tomato plants as affected by root absorbed growth substances and atmospheric carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Tognoni, F; Halevy, A H; Wittwer, S H

    1967-01-01

    Bean and tomato plants were grown in solution culture root media containing pre-determined concentrations of gibberellin A/sub 3/ (GA), 1-naphthalene-acetic acid (NAA), N/sup 6/-benzyladenine (BA), (2-chloroethyl)trimethylammonium chloride (CCC), and at atmospheric levels of 300 and 1000 ppm of CO/sub 2/. Net assimilation rates (NAR), relative growth rates (RGR), leaf area ratios (LAR), root to top dry weight ratios (R/T) and changes in dry weight, size, and form of each organ were recorded. Gibberellin had no effect on RGR of either plant species but increased the NAR of tomatoes at 1000 ppm CO/sub 2/. Total dry weight was only slightly affected by GA but root growth and R/T were markedly depressed. CCC had no effect on NAR, but decreased RGR and LAR. Root growth of beans and R/T in both plants were promoted by CCC. NAR and RGR were strongly inhibited by BA and NAA. Inhibition of stem and leaf growth by CCC and NAA was greater than that for roots; thus, R/T ratios were increased. Root branching was promoted by NAA. High (1000 ppm), compared to the low (300 ppm), atmospheric levels of CO/sub 2/ generally promoted root growth and produced an increase in the R/T, both in the absence and presence of chemical treatment. The multiplicity of effects of the root-absorbed chemical growth substances and CO/sub 2/ on growth and photosynthesis is discussed.

  7. N,N-dimethyl hexadecylamine and related amines regulate root morphogenesis via jasmonic acid signaling in Arabidopsis thaliana.

    Science.gov (United States)

    Raya-González, Javier; Velázquez-Becerra, Crisanto; Barrera-Ortiz, Salvador; López-Bucio, José; Valencia-Cantero, Eduardo

    2017-05-01

    Plant growth-promoting rhizobacteria are natural inhabitants of roots, colonize diverse monocot and dicot species, and affect several functional traits such as root architecture, adaptation to adverse environments, and protect plants from pathogens. N,N-dimethyl-hexadecylamine (C16-DMA) is a rhizobacterial amino lipid that modulates the postembryonic development of several plants, likely as part of volatile blends. In this work, we evaluated the bioactivity of C16-DMA and other related N,N-dimethyl-amines with varied length and found that inhibition of primary root growth was related to the length of the acyl chain. C16-DMA inhibited primary root growth affecting cell division and elongation, while promoting lateral root formation and root hair growth and density in Arabidopsis thaliana (Arabidopsis) wild-type (WT) seedlings. Interestingly, C16-DMA induced the expression of the jasmonic acid (JA)-responsive gene marker pLOX2:uidA, while JA-related mutants jar1, coi1-1, and myc2 affected on JA biosynthesis and perception, respectively, are compromised in C16-DMA responses. Comparison of auxin-regulated gene expression, root architectural changes in WT, and auxin-related mutants aux1-7, tir1/afb2/afb3, and arf7-1/arf19-1 to C16-DMA shows that the C16-DMA effects occur independently of auxin signaling. Together, these results reveal a novel class of aminolipids modulating root organogenesis via crosstalk with the JA signaling pathway.

  8. The components of rice and watermelon root exudates and their effects on pathogenic fungus and watermelon defense.

    Science.gov (United States)

    Ren, Lixuan; Huo, Hongwei; Zhang, Fang; Hao, Wenya; Xiao, Liang; Dong, Caixia; Xu, Guohua

    2016-06-02

    Watermelon (Citrullus lanatus) is susceptible to wilt disease caused by the fungus Fusarium oxysporum f. sp niveum (FON). Intercropping management of watermelon/aerobic rice (Oryza sativa) alleviates watermelon wilt disease, because some unidentified component(s) in rice root exudates suppress FON sporulation and spore germination. Here, we show that the phenolic acid p-coumaric acid is present in rice root exudates only, and it inhibits FON spore germination and sporulation. We found that exogenously applied p-coumaric acid up-regulated the expression of ClPR3 in roots, as well as increased chitinase activity in leaves. Furthermore, exogenously applied p-coumaric acid increased β-1,3-glucanase activity in watermelon roots. By contrast, we found that ferulic acid was secreted by watermelon roots, but not by rice roots, and that it stimulated spore germination and sporulation of FON. Exogenous application of ferulic acid down-regulated ClPR3 expression and inhibited chitinase activity in watermelon leaves. Salicylic acid was detected in both watermelon and rice root exudates, which stimulated FON spore germination at low concentrations and suppressed spore germination at high concentrations. Exogenously applied salicylic acid did not alter ClPR3 expression, but did increase chitinase and β-1,3-glucanase activities in watermelon leaves. Together, our results show that the root exudates of phenolic acids were different between rice and watermelon, which lead to their special ecological roles on pathogenic fungus and watermelon defense.

  9. Orthodontic tooth movement and root resorption in ovariectomized rats treated by systemic administration of zoledronic acid.

    Science.gov (United States)

    Sirisoontorn, Irin; Hotokezaka, Hitoshi; Hashimoto, Megumi; Gonzales, Carmen; Luppanapornlarp, Suwannee; Darendeliler, M Ali; Yoshida, Noriaki

    2012-05-01

    The effect of zoledronic acid, a potent and novel bisphosphonate, on tooth movement and orthodontically induced root resorption in osteoporotic animals systemically treated with zoledronic acid as similarly used in postmenopausal patients has not been elucidated. Therefore, this study was undertaken. Fifteen 10-week-old female Wistar rats were divided into 3 groups: ovariectomy, ovariectomy + zoledronic acid, and control. Only the ovariectomy and ovariectomy + zoledronic acid groups underwent ovariectomies. Two weeks after the ovariectomy, zoledronic acid was administered only to the ovariectomy + zoledronic acid group. Four weeks after the ovariectomy, 25-g nickel-titanium closed-coil springs were applied to observe tooth movement and orthodontically induced root resorption. There were significant differences in the amounts of tooth movement and orthodontically induced root resorption between the ovariectomy and the control groups, and also between the ovariectomy and the ovariectomy + zoledronic acid groups. There was no statistically significant difference in tooth movement and orthodontically induced root resorption between the ovariectomy + zoledronic acid and the control groups. Zoledronic acid inhibited significantly more tooth movement and significantly reduced the severity of orthodontically induced root resorption in the ovariectomized rats. The ovariectomy + zoledronic acid group showed almost the same results as did the control group in both tooth movement and orthodontically induced root resorption. Zoledronic acid inhibits excessive orthodontic tooth movement and also reduces the risk of severe orthodontically induced root resorption in ovariectomized rats. Copyright © 2012 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  10. Root-Securing and Brain-Fortifying Liquid Upregulates Caveolin-1 in Cell Model with Alzheimer’s Disease through Inhibiting Tau Phosphorylation

    Directory of Open Access Journals (Sweden)

    Depei Yuan

    2017-01-01

    Full Text Available In order to explore the effect of root-securing and brain-fortifying Liquid- (RSBFL- mediated caveolin-1 (CAV-1 on phosphorylation of Tau protein and to uncover underlying mechanisms of RSBFL for the prevention and treatment of Alzheimer’s disease (AD, hippocampal neurons isolated from neonatal SD rats and cultured in DMEM-F12 medium were induced by exogenous Aβ1–42 to establish a cell model with AD. Meanwhile, pEGFP-C1-CAV1 and CAV1-shRNA plasmids were transfected into hippocampal neurons for CAV-1 overexpression and silence, respectively. The serum containing RSBFL was prepared for the intervention of AD model cells. The expression of CAV-1, GSK-3β, and p-Tau in normal hippocampal neurons and AD model cells in the presence of serum containing RSBFL was evaluated. The model hippocampal neurons with AD induced by Aβ1–42 revealed an obvious CAV-1 inhibition, enhanced GSK-3β activity, and abnormal Tau phosphorylation. In contrast, the treatment with serum containing RSBFL could upregulate CAV-1 in AD hippocampal neurons (P<0.05 with improved p-GSK-3βSer9 and reduced p-GSK-3βTyr216 (P<0.01, as well as suppressed abnormal phosphorylation of Tau protein. Therefore, RSBFL has an excellent protective effect on hippocampal neurons through increasing CAV-1 expression, inhibiting GSK-3β activity, and reducing excessive abnormal phosphorylation of Tau protein.

  11. Enhanced lignin monomer production caused by cinnamic Acid and its hydroxylated derivatives inhibits soybean root growth.

    Directory of Open Access Journals (Sweden)

    Rogério Barbosa Lima

    Full Text Available Cinnamic acid and its hydroxylated derivatives (p-coumaric, caffeic, ferulic and sinapic acids are known allelochemicals that affect the seed germination and root growth of many plant species. Recent studies have indicated that the reduction of root growth by these allelochemicals is associated with premature cell wall lignification. We hypothesized that an influx of these compounds into the phenylpropanoid pathway increases the lignin monomer content and reduces the root growth. To confirm this hypothesis, we evaluated the effects of cinnamic, p-coumaric, caffeic, ferulic and sinapic acids on soybean root growth, lignin and the composition of p-hydroxyphenyl (H, guaiacyl (G and syringyl (S monomers. To this end, three-day-old seedlings were cultivated in nutrient solution with or without allelochemical (or selective enzymatic inhibitors of the phenylpropanoid pathway in a growth chamber for 24 h. In general, the results showed that 1 cinnamic, p-coumaric, caffeic and ferulic acids reduced root growth and increased lignin content; 2 cinnamic and p-coumaric acids increased p-hydroxyphenyl (H monomer content, whereas p-coumaric, caffeic and ferulic acids increased guaiacyl (G content, and sinapic acid increased sinapyl (S content; 3 when applied in conjunction with piperonylic acid (PIP, an inhibitor of the cinnamate 4-hydroxylase, C4H, cinnamic acid reduced H, G and S contents; and 4 when applied in conjunction with 3,4-(methylenedioxycinnamic acid (MDCA, an inhibitor of the 4-coumarate:CoA ligase, 4CL, p-coumaric acid reduced H, G and S contents, whereas caffeic, ferulic and sinapic acids reduced G and S contents. These results confirm our hypothesis that exogenously applied allelochemicals are channeled into the phenylpropanoid pathway causing excessive production of lignin and its main monomers. By consequence, an enhanced stiffening of the cell wall restricts soybean root growth.

  12. Mercury-induced biochemical and proteomic changes in rice roots.

    Science.gov (United States)

    Chen, Yun-An; Chi, Wen-Chang; Huang, Tsai-Lien; Lin, Chung-Yi; Quynh Nguyeh, Thi Thuy; Hsiung, Yu-Chywan; Chia, Li-Chiao; Huang, Hao-Jen

    2012-06-01

    Mercury (Hg) is a serious environmental pollution threats to the planet. Accumulation of Hg in plants disrupts many cellular-level functions and inhibits growth and development, but the mechanism is not fully understood. We investigated cellular, biochemical and proteomic changes in rice roots under Hg stress. Root growth rate was decreased and Hg, reactive oxygen species (ROS), and malondialdehyde (MDA) content and lipoxygenase activity were increased significantly with increasing Hg concentration in roots. We revealed a time-dependent alteration in total glutathione content and enzymatic activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POD) during Hg stress. 2-D electrophoresis revealed differential expression of 25 spots with Hg treatment of roots: 14 spots were upregulated and 11 spots downregulated. These differentially expressed proteins were identified by ESI-MS/MS to be involved in cellular functions including redox and hormone homeostasis, chaperone activity, metabolism, and transcription regulation. These results may provide new insights into the molecular basis of the Hg stress response in plants. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  13. Gravimorphism in rice and barley: promotion of leaf elongation by vertical inversion in agravitropically growing plants.

    Science.gov (United States)

    Abe, K; Takahashi, H; Suge, H

    1998-12-01

    We have compared shoot responses of agravitropic rice and barley plants to vertical inversion with those of normal ones. When rice plants were vertically inverted, the main stems of a japonica type of rice, cv. Kamenoo, showed negative gravitropism at nodes 2-15 of both elongated and non-elongated internodes. However, shoots of lazy line of rice, lazy-Kamenoo, bent gravitropically at nodes 11-15 only elongated internodes but not at nodes 2-10 of non-elongated ones. Thus, shoots of Kamenoo responded gravitropically at all stages of growth, whereas shoots of lazy-Kamenoo did not show gravitropic response before heading. In Kamenoo plants, lengths of both leaf-sheath and leaf-blade were shortened by vertical inversion, but those of the vertically inverted plants of lazy-Kamenoo were significantly longer than the plants in an upright position. When agravitropic and normal plants of barley were vertically inverted, the same results as in rice were obtained; elongation of both leaf-sheath and leaf-blade was inhibited in normal barley plants, Chikurin-Ibaragi No. 1, but significantly stimulated in agravitropic plants of serpentina barley. These results suggest that vertical inversion of rice and barley plants enhances the elongation growth of leaves in the absence of tropistic response.

  14. Responses of root architecture development to low phosphorus availability: a review.

    Science.gov (United States)

    Niu, Yao Fang; Chai, Ru Shan; Jin, Gu Lei; Wang, Huan; Tang, Cai Xian; Zhang, Yong Song

    2013-07-01

    Phosphorus (P) is an essential element for plant growth and development but it is often a limiting nutrient in soils. Hence, P acquisition from soil by plant roots is a subject of considerable interest in agriculture, ecology and plant root biology. Root architecture, with its shape and structured development, can be considered as an evolutionary response to scarcity of resources. This review discusses the significance of root architecture development in response to low P availability and its beneficial effects on alleviation of P stress. It also focuses on recent progress in unravelling cellular, physiological and molecular mechanisms in root developmental adaptation to P starvation. The progress in a more detailed understanding of these mechanisms might be used for developing strategies that build upon the observed explorative behaviour of plant roots. The role of root architecture in alleviation of P stress is well documented. However, this paper describes how plants adjust their root architecture to low-P conditions through inhibition of primary root growth, promotion of lateral root growth, enhancement of root hair development and cluster root formation, which all promote P acquisition by plants. The mechanisms for activating alterations in root architecture in response to P deprivation depend on changes in the localized P concentration, and transport of or sensitivity to growth regulators such as sugars, auxins, ethylene, cytokinins, nitric oxide (NO), reactive oxygen species (ROS) and abscisic acid (ABA). In the process, many genes are activated, which in turn trigger changes in molecular, physiological and cellular processes. As a result, root architecture is modified, allowing plants to adapt effectively to the low-P environment. This review provides a framework for understanding how P deficiency alters root architecture, with a focus on integrated physiological and molecular signalling.

  15. Responses of root architecture development to low phosphorus availability: a review

    Science.gov (United States)

    Niu, Yao Fang; Chai, Ru Shan; Jin, Gu Lei; Wang, Huan; Tang, Cai Xian; Zhang, Yong Song

    2013-01-01

    Background Phosphorus (P) is an essential element for plant growth and development but it is often a limiting nutrient in soils. Hence, P acquisition from soil by plant roots is a subject of considerable interest in agriculture, ecology and plant root biology. Root architecture, with its shape and structured development, can be considered as an evolutionary response to scarcity of resources. Scope This review discusses the significance of root architecture development in response to low P availability and its beneficial effects on alleviation of P stress. It also focuses on recent progress in unravelling cellular, physiological and molecular mechanisms in root developmental adaptation to P starvation. The progress in a more detailed understanding of these mechanisms might be used for developing strategies that build upon the observed explorative behaviour of plant roots. Conclusions The role of root architecture in alleviation of P stress is well documented. However, this paper describes how plants adjust their root architecture to low-P conditions through inhibition of primary root growth, promotion of lateral root growth, enhancement of root hair development and cluster root formation, which all promote P acquisition by plants. The mechanisms for activating alterations in root architecture in response to P deprivation depend on changes in the localized P concentration, and transport of or sensitivity to growth regulators such as sugars, auxins, ethylene, cytokinins, nitric oxide (NO), reactive oxygen species (ROS) and abscisic acid (ABA). In the process, many genes are activated, which in turn trigger changes in molecular, physiological and cellular processes. As a result, root architecture is modified, allowing plants to adapt effectively to the low-P environment. This review provides a framework for understanding how P deficiency alters root architecture, with a focus on integrated physiological and molecular signalling. PMID:23267006

  16. Evaluation of an Aqueous Extract from Horseradish Root (Armoracia rusticana Radix against Lipopolysaccharide-Induced Cellular Inflammation Reaction

    Directory of Open Access Journals (Sweden)

    Corinna Herz

    2017-01-01

    Full Text Available Horseradish (Armoracia rusticana is a perennial crop and its root is used in condiments. Traditionally, horseradish root is used to treat bacterial infections of the respiratory tract and urinary bladder. The antiphlogistic activity, determined in activated primary human peripheral blood mononuclear cells (PBMC, was evaluated for an aqueous extract and its subfractions, separated by HPLC. Compound analysis was done by UHPLC-QToF/MS and GC-MS. The aqueous extract concentration-dependently inhibited the anti-inflammatory response to lipopolysaccharide (LPS in terms of TNF-α release at ≥37 μg/mL. Further, the cyclooxygenase as well as lipoxygenase pathway was blocked by the extract as demonstrated by inhibition of COX-2 protein expression and PGE2 synthesis at ≥4 μg/mL and leukotriene LTB4 release. Mechanistic studies revealed that inhibition of ERK1/2 and c-Jun activation preceded COX-2 suppression upon plant extract treatment in the presence of LPS. Chemical analysis identified target compounds with a medium polarity as relevant for the observed bioactivity. Importantly, allyl isothiocyanate, which is quite well known for its anti-inflammatory capacity and as the principal pungent constituent in horseradish roots, was not relevant for the observations. The results suggest that horseradish root exerts an antiphlogistic activity in human immune cells by regulation of the COX and LOX pathway via MAPK signalling.

  17. Evaluation of an Aqueous Extract from Horseradish Root (Armoracia rusticana Radix) against Lipopolysaccharide-Induced Cellular Inflammation Reaction.

    Science.gov (United States)

    Herz, Corinna; Tran, Hoai Thi Thu; Márton, Melinda-Rita; Maul, Ronald; Baldermann, Susanne; Schreiner, Monika; Lamy, Evelyn

    2017-01-01

    Horseradish ( Armoracia rusticana ) is a perennial crop and its root is used in condiments. Traditionally, horseradish root is used to treat bacterial infections of the respiratory tract and urinary bladder. The antiphlogistic activity, determined in activated primary human peripheral blood mononuclear cells (PBMC), was evaluated for an aqueous extract and its subfractions, separated by HPLC. Compound analysis was done by UHPLC-QToF/MS and GC-MS. The aqueous extract concentration-dependently inhibited the anti-inflammatory response to lipopolysaccharide (LPS) in terms of TNF- α release at ≥37  μ g/mL. Further, the cyclooxygenase as well as lipoxygenase pathway was blocked by the extract as demonstrated by inhibition of COX-2 protein expression and PGE 2 synthesis at ≥4  μ g/mL and leukotriene LTB4 release. Mechanistic studies revealed that inhibition of ERK1/2 and c-Jun activation preceded COX-2 suppression upon plant extract treatment in the presence of LPS. Chemical analysis identified target compounds with a medium polarity as relevant for the observed bioactivity. Importantly, allyl isothiocyanate, which is quite well known for its anti-inflammatory capacity and as the principal pungent constituent in horseradish roots, was not relevant for the observations. The results suggest that horseradish root exerts an antiphlogistic activity in human immune cells by regulation of the COX and LOX pathway via MAPK signalling.

  18. GmPGIP3 enhanced resistance to both take-all and common root rot diseases in transgenic wheat.

    Science.gov (United States)

    Wang, Aiyun; Wei, Xuening; Rong, Wei; Dang, Liang; Du, Li-Pu; Qi, Lin; Xu, Hui-Jun; Shao, Yanjun; Zhang, Zengyan

    2015-05-01

    Take-all (caused by the fungal pathogen Gaeumannomyces graminis var. tritici, Ggt) and common root rot (caused by Bipolaris sorokiniana) are devastating root diseases of wheat (Triticum aestivum L.). Development of resistant wheat cultivars has been a challenge since no resistant wheat accession is available. GmPGIP3, one member of polygalacturonase-inhibiting protein (PGIP) family in soybean (Glycine max), exhibited inhibition activity against fungal endopolygalacturonases (PGs) in vitro. In this study, the GmPGIP3 transgenic wheat plants were generated and used to assess the effectiveness of GmPGIP3 in protecting wheat from the infection of Ggt and B. sorokiniana. Four independent transgenic lines were identified by genomic PCR, Southern blot, and reverse transcription PCR (RT-PCR). The introduced GmPGIP3 was integrated into the genomes of these transgenic lines and could be expressed. The expressing GmPGIP3 protein in these transgenic wheat lines could inhibit the PGs produced by Ggt and B. sorokiniana. The disease response assessments postinoculation showed that the GmPGIP3-expressing transgenic wheat lines displayed significantly enhanced resistance to both take-all and common root rot diseases caused by the infection of Ggt and B. sorokiniana. These data suggested that GmPGIP3 is an attractive gene resource in improving resistance to both take-all and common root rot diseases in wheat.

  19. The influence of ascorbic acid on the oxygen consumption and the heat production by the cells of wheat seedling roots with their mitochondrial electron transport chain inhibited at complexes I and III

    International Nuclear Information System (INIS)

    Gordon, L.K.; Rakhmatullina, D.F.; Ogorodnikova, T.I.; Alyabyev, A.J.; Minibayeva, F.V.; Loseva, N.L.; Mityashina, S.Y.

    2007-01-01

    The influence of exogenous ascorbic acid (AsA) on oxidative phosphorylation was studied using wheat seedling roots. Treatment of them with AsA stimulated the rates of oxygen consumption and the heat production and caused a decrease of the respiratory coefficient. The increase in respiration was prevented by inhibitors of ascorbate oxidase, diethyldithiocarbamate (DEDTC), and of cytochrome oxidase, cyanide (KCN). Exogenous AsA sharply stimulated the rate of oxygen consumption of roots when complexes I and III of the mitochondrial electron transport chain were inhibited by rotenone and antimycin A, respectively, while the rates of heat production did not change significantly. It is concluded that AsA is a potent energy substrate, which can be used in conditions of failing I and III complexes in the mitochondrial electron transport chain

  20. Sporamin-mediated resistance to beet cyst nematodes (Heterodera schachtii Schm.) is dependent on trypsin inhibitory activity in sugar beet (Beta vulgaris L.) hairy roots.

    Science.gov (United States)

    Cai, Daguang; Thurau, Tim; Tian, Yanyan; Lange, Tina; Yeh, Kai-Wun; Jung, Christian

    2003-04-01

    Sporamin, a sweet potato tuberous storage protein, is a Kunitz-type trypsin inhibitor. Its capability of conferring insect-resistance on transgenic tobacco and cauliflower has been confirmed. To test its potential as an anti-feedant for the beet cyst nematode (Heterodera schachtii Schm.), the sporamin gene SpTI-1 was introduced into sugar beet (Beta vulgaris L.) by Agrobacterium rhizogenes-mediated transformation. Twelve different hairy root clones expressing sporamin were selected for studying nematode development. Of these, 8 hairy root clones were found to show significant efficiency in inhibiting the growth and development of the female nematodes whereas 4 root clones did not show any inhibitory effects even though the SpTI-1 gene was regularly expressed in all of the tested hairy roots as revealed by northern and western analyses. Inhibition of nematode development correlated with trypsin inhibitor activity but not with the amount of sporamin expressed in hairy roots. These data demonstrate that the trypsin inhibitor activity is the critical factor for inhibiting growth and development of cyst nematodes in sugar beet hairy roots expressing the sporamin gene. Hence, the sweet potato sporamin can be used as a new and effective anti-feedant for controlling cyst nematodes offering an alternative strategy for establishing nematode resistance in crops.

  1. Hyaluronidase and protease activities from Indian snake venoms: neutralization by Mimosa pudica root extract.

    Science.gov (United States)

    Girish, K S; Mohanakumari, H P; Nagaraju, S; Vishwanath, B S; Kemparaju, K

    2004-06-01

    The aqueous root extract of Mimosa pudica dose dependently inhibited the hyaluronidase and protease activities of Indian snakes (Naja naja, Vipera russelii and Echis carinatus) venom. Copyright 2004 Elsevier B.V.

  2. Genetic association among root morphology, root quality and root yield in ashwagandha (Withania somnifera)

    OpenAIRE

    Kumar Ramesh R.; Reddy Anjaneya Prasanna L.; Subbaiah Chinna J.; Kumar Niranjana A.; Prasad Nagendra H.N.; Bhukya Balakishan

    2011-01-01

    Ashwagandha (Withania somnifera) is a dryland medicinal crop and roots are used as valuable drug in traditional systems of medicine. Morphological variants (morphotypes) and the parental populations were evaluated for root - morphometric, quality and yield traits to study genetic association among them. Root morphometric traits (root length, root diameter, number of secondary roots/ plant) and crude fiber content exhibited strong association among them and ...

  3. Cellular mechanisms for presynaptic inhibition of sensory afferents

    DEFF Research Database (Denmark)

    Perrier, Jean-Francois Marie; delgado-lezama, rodolfo; Christensen, Rasmus Kordt

    It is well established that presynaptic inhibition of primary afferents involves the activation of GABAA receptors located on presynaptic terminals. However, the source of GABA remains unknown. In an integrated preparation of the spinal cord of the adult turtle, we evoked dorsal root potentials...

  4. Root uptake and phytotoxicity of nanosized molybdenum octahedral clusters

    International Nuclear Information System (INIS)

    Aubert, Tangi; Burel, Agnès; Esnault, Marie-Andrée; Cordier, Stéphane; Grasset, Fabien; Cabello-Hurtado, Francisco

    2012-01-01

    Highlights: ► We investigated the effect of nanosized Mo 6 clusters on the growth of rapeseed plants. ► The aggregation state of the clusters depends on the dispersion medium. ► The concentration-dependant toxicity of the clusters depends on aggregation state. ► We took into account the possible contribution to toxicity of dissolved ionic species. ► The root uptake of the clusters was followed by NanoSIMS. - Abstract: Here are examined the root uptake and phytotoxicity of octahedral hexamolybdenum clusters on rapeseed plants using the solid state compound Cs 2 Mo 6 Br 14 as cluster precursor. [Mo 6 Br 14 ] 2− cluster units are nanosized entities offering a strong and stable emission in the near-infrared region with numerous applications in biotechnology. To investigate cluster toxicity on rapeseed plants, two different culture systems have been set up, using either a water-sorbing suspension of cluster aggregates or an ethanol-sorbing solution of dispersed nanosized clusters. Size, shape, surface area and state of clusters in both medium were analyzed by FE-SEM, BET and XPS. The potential contribution of cluster dissolution to phytotoxicity was evaluated by ICP-OES and toxicity analysis of Mo, Br and Cs. We showed that the clusters did not affect seed germination but greatly inhibited plant growth. This inhibition was much more important when plants were treated with nanosized entities than with microsized cluster aggregates. In addition, nanosized clusters affected the root morphology in a different manner than microsized cluster aggregates, as shown by FE-SEM observations. The root penetration of the clusters was followed by secondary ion mass spectroscopy with high spatial resolution (NanoSIMS) and was also found to be much more important for treatments with nanosized clusters.

  5. Root uptake and phytotoxicity of nanosized molybdenum octahedral clusters

    Energy Technology Data Exchange (ETDEWEB)

    Aubert, Tangi [Solid State Chemistry and Materials Group, UMR CNRS 6226 Sciences Chimiques de Rennes, University of Rennes 1, 263 av. du General Leclerc, Campus de Beaulieu, 35042 Rennes (France); Burel, Agnes [Electronic Microscopy Department, University of Rennes 1, 2 av. du Professeur Leon-Bernard, Campus de Villejean, 35043 Rennes (France); Esnault, Marie-Andree [Mechanisms at the Origin of Biodiversity Team, UMR CNRS 6553 Ecobio, University of Rennes 1, 263 av. du General Leclerc, Campus de Beaulieu, 35042 Rennes (France); Cordier, Stephane; Grasset, Fabien [Solid State Chemistry and Materials Group, UMR CNRS 6226 Sciences Chimiques de Rennes, University of Rennes 1, 263 av. du General Leclerc, Campus de Beaulieu, 35042 Rennes (France); Cabello-Hurtado, Francisco, E-mail: francisco.cabello@univ-rennes1.fr [Mechanisms at the Origin of Biodiversity Team, UMR CNRS 6553 Ecobio, University of Rennes 1, 263 av. du General Leclerc, Campus de Beaulieu, 35042 Rennes (France)

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer We investigated the effect of nanosized Mo{sub 6} clusters on the growth of rapeseed plants. Black-Right-Pointing-Pointer The aggregation state of the clusters depends on the dispersion medium. Black-Right-Pointing-Pointer The concentration-dependant toxicity of the clusters depends on aggregation state. Black-Right-Pointing-Pointer We took into account the possible contribution to toxicity of dissolved ionic species. Black-Right-Pointing-Pointer The root uptake of the clusters was followed by NanoSIMS. - Abstract: Here are examined the root uptake and phytotoxicity of octahedral hexamolybdenum clusters on rapeseed plants using the solid state compound Cs{sub 2}Mo{sub 6}Br{sub 14} as cluster precursor. [Mo{sub 6}Br{sub 14}]{sup 2-} cluster units are nanosized entities offering a strong and stable emission in the near-infrared region with numerous applications in biotechnology. To investigate cluster toxicity on rapeseed plants, two different culture systems have been set up, using either a water-sorbing suspension of cluster aggregates or an ethanol-sorbing solution of dispersed nanosized clusters. Size, shape, surface area and state of clusters in both medium were analyzed by FE-SEM, BET and XPS. The potential contribution of cluster dissolution to phytotoxicity was evaluated by ICP-OES and toxicity analysis of Mo, Br and Cs. We showed that the clusters did not affect seed germination but greatly inhibited plant growth. This inhibition was much more important when plants were treated with nanosized entities than with microsized cluster aggregates. In addition, nanosized clusters affected the root morphology in a different manner than microsized cluster aggregates, as shown by FE-SEM observations. The root penetration of the clusters was followed by secondary ion mass spectroscopy with high spatial resolution (NanoSIMS) and was also found to be much more important for treatments with nanosized clusters.

  6. Modes of Antiviral Action of Chemical Portions and Constituents from Woad Root Extract against Influenza Virus A FM1

    Directory of Open Access Journals (Sweden)

    Jia-Hang Su

    2016-01-01

    Full Text Available Woad root has been used for the prevention of influenza for hundreds of years in many Asian countries. In this study, the antiviral modes of clemastanin B (CB, epigoitrin, phenylpropanoid portion (PEP, and the mixture of phenylpropanoids, alkaloids, and organic acid portions (PEP + ALK + OA from wood root extract against influenza virus A FM1 were investigated. The results revealed that CB, epigoitrin, PEP, and PEP + ALK + OA exert their anti-influenza activity via inhibiting the virus multiplication, prophylaxis, and blocking the virus attachment. The primary mode of action of PEP and PEP + ALK + OA is the inhibition of virus replication. The inhibitory effect on virus attachment and multiplication is the main modes for epigoitrin. All the compounds or chemical portions from woad root extract tested in this study do not have direct virucidal activity. Our results provided the comprehensive analysis of the antiviral mechanism of wood root extract.

  7. Evaluation of Antimicrobial Activity of Root Extracts of Abitulon indicum

    Directory of Open Access Journals (Sweden)

    Krishna Rao MORTHA

    2015-06-01

    Full Text Available Antimicrobial activity of Abitulon indicum roots was studied against seven pathogenic bacteria and three fungal strains by agar well diffusion method. Antimicrobial activity was recorded for hexane, chloroform, methanol, ethanol and aqueous extracts. Alcohol (ethanol and methanol extracts exhibited the highest degree of antimicrobial activity compared to aqueous, chloroform and hexane extracts. Pseudomonas aeruginosa was turned out to be the most susceptible bacterium to the crude root chemical constituents, using the standard Tetracycline and Clotrimazole. Minimum inhibition concentration values of hexane, chloroform, methanol, ethanol and aqueous extracts were determined by the agar dilution method and ranged between 62.5 and 1,000 µg. The study suggested that the root extracts possess bioactive compounds with antimicrobial activity against the tested bacteria and fungi, revealing a significant scope to develop a novel broad spectrum of antimicrobial drug formulation from Abitulon indicum.

  8. Phytochemical Characterization of Low Molecular Weight Constituents from Marshmallow Roots (Althaea officinalis) and Inhibiting Effects of the Aqueous Extract on Human Hyaluronidase-1.

    Science.gov (United States)

    Sendker, Jandirk; Böker, Ines; Lengers, Isabelle; Brandt, Simone; Jose, Joachim; Stark, Timo; Hofmann, Thomas; Fink, Careen; Abdel-Aziz, Heba; Hensel, Andreas

    2017-02-24

    Extract RE was obtained from the roots of Althaea officinalis in a yield of 8.1%, related to the dried plant material, by extraction with MeOH-H 2 O (1:1), followed by precipitation with EtOH to remove high molecular weight constituents. Phytochemical investigation of RE revealed the presence of N-phenylpropenoyl-l-amino acid amides 1-5, 8% glycine betaine 6, about 9% total amino acids with proline as the main compound, and about 61% mono- and oligomeric carbohydrates with sucrose as the main compound. Further fractionation revealed the presence of a hypolaetin diglycoside (12) and four hypolaetin glycosides (7-9 and 11) with O-sulfocarbohydrate moieties; additionally, 4'-O-methylisoscutellarein-8-O-β-d-(3″-O-sulfo)glucuronopyranoside (10) and the diglycosylated coumarin haploperoside D (13) were identified. The hypolaetin-O-sulfoglycosides 7-10 are new natural products. RE inhibited the enzymatic activity of surface-displayed human hyaluronidase-1 on Escherichia coli F470 cells with an IC 50 of 7.7 mg/mL. RE downregulated mRNA expression of hyal-1 in HaCaT keratinocytes at 125 and 250 μg/mL, respectively. These data contribute to a deeper phytochemical understanding of marshmallow root extracts and to the positive influence of extracts used for therapy of irritated and inflamed buccal tissue and cough.

  9. Induction of hypoxic root metabolism results from physical limitations in O2 bioavailability in microgravity.

    Science.gov (United States)

    Liao, J; Liu, G; Monje, O; Stutte, G W; Porterfield, D M

    2004-01-01

    Numerous spaceflight experiments have noted changes in the roots that are consistent with hypoxia in the root zone. These observations include general ultrastructure analysis and biochemical measurements to direct measurements of stress specific enzymes. In experiments that have monitored alcohol dehydrogenase (ADH), the data shows this hypoxically responsive gene is induced and is associated with increased ADH activity in microgravity. These changes in ADH could be induced either by spaceflight hypoxia resulting from inhibition of gravity mediated O2 transport, or by a non-specific stress response due to inhibition of gravisensing. We tested these hypotheses in a series of two experiments. The objective of the first experiment was to determine if physical changes in gravity-mediated O2 transport can be directly measured, while the second series of experiments tested whether disruption of gravisensing can induce a non-specific ADH response. To directly measure O2 bioavailability as a function of gravity, we designed a sensor that mimics metabolic oxygen consumption in the rhizosphere. Because of these criteria, the sensor is sensitive to any changes in root O2 bioavailability that may occur in microgravity. In a KC-135 experiment, the sensor was implanted in a moist granular clay media and exposed to microgravity during parabolic flight. The resulting data indicated that root O2 bioavailability decreased in phase with gravity. In experiments that tested for non-specific induction of ADH, we compared the response of transgenic Arabidopsis plants (ADH promoted GUS marker gene) exposed to clinostat, control, and waterlogged conditions. The plants were grown on agar slats in a growth chamber before being exposed to the experimental treatments. The plants were stained for GUS activity localization, and subjected to biochemical tests for ADH, and GUS enzyme activity. These tests showed that the waterlogging treatment induced significant increases in GUS and ADH enzyme

  10. Simplified and representative bacterial community of maize roots.

    Science.gov (United States)

    Niu, Ben; Paulson, Joseph Nathaniel; Zheng, Xiaoqi; Kolter, Roberto

    2017-03-21

    Plant-associated microbes are important for the growth and health of their hosts. As a result of numerous prior studies, we know that host genotypes and abiotic factors influence the composition of plant microbiomes. However, the high complexity of these communities challenges detailed studies to define experimentally the mechanisms underlying the dynamics of community assembly and the beneficial effects of such microbiomes on plant hosts. In this work, from the distinctive microbiota assembled by maize roots, through host-mediated selection, we obtained a greatly simplified synthetic bacterial community consisting of seven strains ( Enterobacter cloacae , Stenotrophomonas maltophilia, Ochrobactrum pituitosum, Herbaspirillum frisingense, Pseudomonas putida, Curtobacterium pusillum , and Chryseobacterium indologenes ) representing three of the four most dominant phyla found in maize roots. By using a selective culture-dependent method to track the abundance of each strain, we investigated the role that each plays in community assembly on roots of axenic maize seedlings. Only the removal of E. cloacae led to the complete loss of the community, and C. pusillum took over. This result suggests that E. cloacae plays the role of keystone species in this model ecosystem. In planta and in vitro, this model community inhibited the phytopathogenic fungus Fusarium verticillioides , indicating a clear benefit to the host. Thus, combined with the selective culture-dependent quantification method, our synthetic seven-species community representing the root microbiome has the potential to serve as a useful system to explore how bacterial interspecies interactions affect root microbiome assembly and to dissect the beneficial effects of the root microbiota on hosts under laboratory conditions in the future.

  11. Root rots

    Science.gov (United States)

    Kathryn Robbins; Philip M. Wargo

    1989-01-01

    Root rots of central hardwoods are diseases caused by fungi that infect and decay woody roots and sometimes also invade the butt portion of the tree. By killing and decaying roots, root rotting fungi reduce growth, decrease tree vigor, and cause windthrow and death. The most common root diseases of central hardwoods are Armillaria root rot, lnonotus root rot, and...

  12. A novel fluorescence imaging approach to monitor salt stress-induced modulation of ouabain-sensitive ATPase activity in sunflower seedling roots.

    Science.gov (United States)

    Mukherjee, Soumya; Bhatla, Satish Chander

    2014-04-01

    Seedlings exposed to salt stress are expected to show modulation of intracellular accumulation of sodium ions through a variety of mechanisms. Using a new methodology, this work demonstrates ouabain (OU)-sensitive ATPase activity in the roots of sunflower seedlings subjected to salt stress (120 mM NaCl). 9-Anthroylouabain (a derivative of ouabain known to inhibit Na(+), K(+) -ATPase activity in animal systems, EC 3.6.3.9) has been used as a probe to analyze OU-sensitive ATPase activity in sunflower (Helianthus annuus) seedling roots by spectrofluorometric estimation and localization of its spatial distribution using confocal laser scanning microscopy. Salt stress for 48 h leads to a significant induction of OU-sensitive ATPase activity in the meristematic region of the seedling roots. Calcium ions (10 mM) significantly inhibit enzyme activity and a parallel accumulation of sodium ions in the cytosol of the columella cells, epidermis and in the cells of the meristematic region of the roots is evident. As a rapid response to NaCl stress, the activity of OU-sensitive ATPase gets localized in the nuclear membrane of root protoplasts and it gets inhibited after treatment with calcium ions. Nuclear membrane localization of the OU-sensitive ATPase activity highlights a possible mechanism to efflux sodium ions from the nucleus. Thus, a correlation between OU-sensitive ATPase activity, its modulation by calcium ions and accumulation of sodium ions in various regions of the seedling roots, has been demonstrated using a novel approach in a plant system. © 2013 Scandinavian Plant Physiology Society.

  13. In vitro rooting of Crocosmia × crocosmiiflora ‘Lucifer’

    Directory of Open Access Journals (Sweden)

    Krupa-Małkiewicz Marcelina

    2017-06-01

    Full Text Available The aim of this study was to determine the effect of various auxins and their concentrations on Crocosmia × crocosmiiflora ‘Lucifer’ rooting in in vitro cultures and in vivo conditions. The initial research materials were shoots obtained from a stabilized in vitro culture. MS media were supplemented with the following auxins: IAA, IBA and NAA at concentrations of 0.5, 1.0, 2.0 and 5.0 mg dm-3. The results of the study showed that hormone applications had a positive effect on the root development of Crocosmia microshoots. 100% rooted shoots were observed in each of the applied combinations of the experiment. The highest number of roots and the longest roots were formed in the presence of IBA at a concentration of 1.0 mg dm-3. IAA, IBA and NAA affected plant height and root morphology of Crocosmia differently. The addition of higher concentrations of auxins to the medium (2.0 and 5.0 mg dm-3 resulted in the formation of short roots. The applied IBA concentrations determined the percentage of the plants that were adapted to in vivo conditions, as well as their vegetative features and the yield of descendant tubers. At the end of the vegetation period, higher IBA concentrations, i.e., 1.0, 2.0 and 5.0 mg dm-3, caused a decrease of up to 50-75% in the obtained plants and also inhibited plant height, as well as the weight and diameter of the tubers formed, compared to the control.

  14. Ion transport in roots of cotton seedlings under the effect of gamma-radiation

    International Nuclear Information System (INIS)

    Kasymov, A.K.

    1976-01-01

    It has been found that small doses (0.1 to 0.5kR) increase the ion transport (K + and Na + ) in seedling roots, and relatively high radiation doses (25 to 100 kR) markedly decrease it. ATPase activity varied with the dose. Mgsup(++)-, Na + - and K + -activated ATPases were more sensitive than a background ATPase. It is suggested that high radiation doses destroy the work of the sodium-potassium pump of cotton root cells inhibiting the activity of the transfer ATPase

  15. The effect of sugars in relation to methyl jasmonate on anthocyanin formation in the roots of Kalanchoe blossfeldiana (Poelln.

    Directory of Open Access Journals (Sweden)

    Justyna Góraj-Koniarska

    2015-07-01

    Full Text Available This study investigated the effects of different sugars (sucrose, fructose, glucose and sugar alcohols (mannitol, sorbitol applied alone and in solution with methyl jasmonate (JA-Me on the anthocyanin content in the roots of Kalanchoe blossfeldiana. None of the sugars used individually in the experiment affected anthocyanin accumulation in the roots of intact plants. The anthocyanin level was similar to that in the control. Sucrose at concentrations of 0.5% and 3.0%, and glucose at a concentration of 3.0% inhibited anthocyanin accumulation induced by JA-Me. Only fructose at a concentration of 3.0% stimulated anthocyanin accumulation induced by JA-Me. The sugar alcohols, mannitol at a concentration of 3.0% and sorbitol at 0.5% and 3.0%, inhibited anthocyanin accumulation in the roots of intact K. blossfeldiana plants induced by JA-Me. In excised roots, both sugars and JA-Me used individually did not affect the formation of anthocyanins. Also, the sugar alcohols (mannitol and sorbitol applied simultaneously with JA-Me had no effect on the accumulation of anthocyanins. However, roots treated with sugars (sucrose, fructose, glucose in solution with JA-Me promoted the induction of anthocyanins in the apical parts of the roots.  The results suggest that anthocyanin elicitation in the roots of K. blossfeldiana by methyl jasmonate may be dependent on the interaction of JA-Me with sugars transported from the stems (leaves to the roots.

  16. Characterization of an inducible UDP-glucose:salicylic acid O-glucosyltransferase from oat roots

    International Nuclear Information System (INIS)

    Yalpani, N.; Schulz, M.; Balke, N.E.

    1990-01-01

    Phytotoxicity of salicylic acid (SA), a phenolic acid that inhibits ion absorption in plant roots, is reduced in oat roots by the action of a UDP-glucose:SA glucosyltransferase (GTase). GTase activity, extracted from oat roots and assayed with [ 14 C]SA, was present at low constitutive levels but increased within 1.5 h of incubation of roots in 0.5 mM SA at pH 6.5. This induction was the result of de novo RNA and protein synthesis. Induction was highly specific towards SA as the inducer. The partially purified, soluble enzyme has a M t of about 50,000 and high specificity towards UDP-glucose as the sugar donor (K m = 0.28 mM) and SA as the glucose acceptor (K m = 0.11 mM). 2-D PAGE of [ 35 S]methionine-labeled proteins extracted from induced and uninduced roots revealed a candidate peptide representing the GTase. This peptide was also present on gels of partially purified GTase

  17. Indole-3-butyric acid mediates antioxidative defense systems to promote adventitious rooting in mung bean seedlings under cadmium and drought stresses.

    Science.gov (United States)

    Li, Shi-Weng; Zeng, Xiao-Ying; Leng, Yan; Feng, Lin; Kang, Xiao-Hu

    2018-06-08

    In vitro experiments were performed to determine whether auxin can mediate the formation of adventitious roots in response to heavy metal and drought stresses using a model rooting plant, mung bean [Vigna radiata (L.) Wilczek]. The treatments with CdCl 2 or mannitol alone significantly inhibited the formation and growth of adventitious roots in mung bean seedlings. In contrast, when CdCl 2 or mannitol was applied together with indole-3-butyric acid (IBA), IBA considerably cancelled the inhibition of adventitious rooting by stresses. Treatment with CdCl 2 or mannitol alone significantly increased the soluble protein and malondialdehyde (MDA) contents. CdCl 2 and mannitol stress each induced differentially significant changes in the activities of antioxidative enzyme and antioxidant levels during adventitious rooting. Notably, both CdCl 2 and mannitol stress strongly reduced the peroxidase (POD) and ascorbate peroxidase (APX) activities and glutathione (GSH) and phenols levels. Catalase and superoxide dismutase (SOD) activity were enhanced by CdCl 2 but reduced by mannitol. CdCl 2 increased the ascorbate acid (ASA) level, which was decreased by mannitol. Furthermore, when CdCl 2 or mannitol was applied together with IBA, IBA counteracted the CdCl 2 - or mannitol-induced increase or decrease in certain antioxidants, MDA, and antioxidative enzymes. These results suggest that Cd and mannitol stress inhibition of adventitious rooting is associated with the regulation of antioxidative enzymes and antioxidants in cells to defense the oxidative stress. Moreover, IBA alleviates the effects of Cd and mannitol stress on the rooting process partially through the regulation of antioxidative defense systems. Copyright © 2018 Elsevier Inc. All rights reserved.

  18. Evaluation of biocontrol potential of epiphytic fluorescent pseudomonas as associated with healthy fruits and vegetables against root rot and root knot pathogens of mungbean

    International Nuclear Information System (INIS)

    Habiba, A.; Noreen, R.; Ali, S. A.; Sultana, V.; Ara, J.

    2016-01-01

    Endophytic and rhizospheric fluorescent Pseudomonas have widely been used as biological control agents against soilborne plant pathogens. In this study, fifteen epiphytic fluorescent Pseudomonas isolated from the surfaces of citrus (grapefruit, orange and lemon) melon and tomato fruits were characterized for their in vitro activity against root rotting fungi viz., Macrophomina phaseolina, Fusarium solani, F. oxysporum and Rhizoctonia solani and nematicidal activity against the second stage juveniles of Meloidogyne javanica. Out of fifteen Pseudomonas isolates HAB-16, HAB-1 and HAB-25 inhibited the growth of all the test fungi and showed maximum nematicidal activity against second stage juvenile of M. javanica. Based on their effective in vitro activity nine epiphytic fluorescent Pseudomonas were evaluated for their growth promoting ability and biocontrol activity in screen house on mungbean. Pseudomonas isolates (HAB-13, HAB-2, HAB-4, HAB-1, HAB-14, HAB-9, HAB-7 and HAB-25) used as soil drench greatly reduced the root rot-root knot infection and thereby enhanced plant growth, root nodulation and yield in mungbean. Besides, rhizospheric and endophytic, epiphytic fluorescent Pseudomonas associated with healthy fruits may be used as biocontrol agent against root rotting fungi, besides, using for the mangemnet of postharvest diseases. (author)

  19. Maize Fungal Growth Control with Scopoletin of Cassava Roots Produced in Benin

    Directory of Open Access Journals (Sweden)

    Rafiatou Ba

    2017-01-01

    Full Text Available The chemical contamination of food is among the main public health issues in developing countries. With a view to find new natural bioactive products against fungi responsible for chemical contamination of staple food such as maize, the antifungal activity tests of scopoletin extracted from different components of the cassava root produced in Benin were carried out. The dosage of scopoletin from parts of the root (first skin, second skin, whole root, and flesh was done by High Performance Liquid Chromatography. The scopoletin extract was used to assess the activity of 12 strains (11 strains of maize and a reference strain. The presence of scopoletin was revealed in all components of the cassava root. Scopoletin extracted from the first skin cassava root was the most active both as inhibition of sporulation (52.29 to 87.91% and the mycelial growth (36.51–80.41%. Scopoletin extract from the cassava root skins showed significant inhibitory activity on the tested strains with fungicide concentration (MFC between 0.0125 mg/mL and 0.1 mg/mL. The antifungal scopoletin extracted from the cassava root skins may be well beneficial for the fungal control of the storage of maize.

  20. Arabidopsis pdr2 reveals a phosphate-sensitive checkpoint in root development.

    Science.gov (United States)

    Ticconi, Carla A; Delatorre, Carla A; Lahner, Brett; Salt, David E; Abel, Steffen

    2004-03-01

    Plants have evolved complex strategies to maintain phosphate (Pi) homeostasis and to maximize Pi acquisition when the macronutrient is limiting. Adjustment of root system architecture via changes in meristem initiation and activity is integral to the acclimation process. However, the mechanisms that monitor external Pi status and interpret the nutritional signal remain to be elucidated. Here, we present evidence that the Pi deficiency response, pdr2, mutation disrupts local Pi sensing. The sensitivity and amplitude of metabolic Pi-starvation responses, such as Pi-responsive gene expression or accumulation of anthocyanins and starch, are enhanced in pdr2 seedlings. However, the most conspicuous alteration of pdr2 is a conditional short-root phenotype that is specific for Pi deficiency and caused by selective inhibition of root cell division followed by cell death below a threshold concentration of about 0.1 mm external Pi. Measurements of general Pi uptake and of total phosphorus (P) in root tips exclude a defect in high-affinity Pi acquisition. Rescue of root meristem activity in Pi-starved pdr2 by phosphite (Phi), a non-metabolizable Pi analog, and divided-root experiments suggest that pdr2 disrupts sensing of low external Pi availability. Thus, PDR2 is proposed to function at a Pi-sensitive checkpoint in root development, which monitors environmental Pi status, maintains and fine-tunes meristematic activity, and finally adjusts root system architecture to maximize Pi acquisition.

  1. Flavonol-induced changes in PIN2 polarity and auxin transport in the Arabidopsis thaliana rol1-2 mutant require phosphatase activity

    Czech Academy of Sciences Publication Activity Database

    Kuhn, B.M.; Nodzynski, T.; Errafi, S.; Bucher, R.; Gupta, S.; Aryal, B.; Dobrev, Petre; Bigler, L.; Geisler, M.; Zažímalová, Eva; Friml, J.; Ringli, Ch.

    2017-01-01

    Roč. 7, FEB 6 (2017), č. článku 41906. ISSN 2045-2322 R&D Projects: GA MŠk(CZ) LQ1601; GA ČR(CZ) GA16-10948S Institutional support: RVO:61389030 Keywords : regulatory subunit * p-glycoproteins * lateral root * protein * efflux * phosphorylation * growth * accumulation * gravitropism * mutation Subject RIV: CE - Biochemistry OBOR OECD: Cell biology Impact factor: 4.259, year: 2016

  2. Toxic effects of Cu2+ on growth, nutrition, root morphology, and distribution of Cu in roots of Sabi grass

    International Nuclear Information System (INIS)

    Kopittke, P.M.; Asher, C.J.; Blamey, F.P.C.; Menzies, N.W.

    2009-01-01

    Sabi grass (Urochloa mosambicensis (Hack.) Dandy) (a C4 species of Poaceae) is commonly used to revegetate disturbed sites in low-rainfall environments, but comparatively little is known regarding copper (Cu) toxicity in this species. A dilute nutrient solution culture experiment was conducted for 10 d to examine the effects of elevated Cu 2+ activities ({Cu 2+ }) on the growth of Sabi grass. Growth was inhibited by high Cu in solution, with a 50% reduction in the relative fresh mass occurring at 1.0 μM {Cu 2+ } for the roots and 1.2 μM {Cu 2+ } for the shoots. In solutions containing 1.2-1.9 μM {Cu 2+ }, many of the roots ruptured due to the tearing and separation of the rhizodermis and outer cortex from the underlying tissues. Transmission electron microscopy revealed that Cu-rich deposits were found to accumulate predominantly within vacuoles. Due to limited translocation of Cu from the roots to the shoots, phytotoxicity is likely to be more of a problem in remediation of Cu-toxic sites than is Cu toxicity of fauna consuming the above-ground biomass.

  3. Regulation of root development in Arabidopsis thaliana by phytohormone-secreting epiphytic methylobacteria.

    Science.gov (United States)

    Klikno, Jana; Kutschera, Ulrich

    2017-09-01

    In numerous experimental studies, seedlings of the model dicot Arabidopsis thaliana have been raised on sterile mineral salt agar. However, under natural conditions, no plant has ever grown in an environment without bacteria. Here, we document that germ-free (gnotobiotic) seedlings, raised on mineral salt agar without sucrose, develop very short root hairs. In the presence of a soil extract that contains naturally occurring microbes, root hair elongation is promoted; this effect can be mimicked by the addition of methylobacteria to germ-free seedlings. Using five different bacterial species (Methylobacterium mesophilicum, Methylobacterium extorquens, Methylobacterium oryzae, Methylobacterium podarium, and Methylobacterium radiotolerans), we show that, over 9 days of seedling development in a light-dark cycle, root development (hair elongation, length of the primary root, branching patterns) is regulated by these epiphytic microbes that occur in the rhizosphere of field-grown plants. In a sterile liquid culture test system, auxin (IAA) inhibited root growth with little effect on hair elongation and significantly stimulated hypocotyl enlargement. Cytokinins (trans-zeatin, kinetin) and ethylene (application of the precursor ACC) likewise exerted an inhibitory effect on root growth but, in contrast to IAA, drastically stimulated root hair elongation. Methylobacteria are phytosymbionts that produce/secrete cytokinins. We conclude that, under real-world conditions (soil), the provision of these phytohormones by methylobacteria (and other epiphytic microbes) regulates root development during seedling establishment.

  4. Colonization of lettuce rhizosphere and roots by tagged Streptomyces

    OpenAIRE

    Maria eBonaldi; Xiaoyulong eChen; Andrea eKunova; Cristina ePizzatti; Marco eSaracchi; Paolo eCortesi

    2015-01-01

    Beneficial microorganisms are increasingly used in agriculture, but their efficacy often fails due to limited knowledge of their interactions with plants and other microorganisms present in rhizosphere. We studied spatio-temporal colonization dynamics of lettuce roots and rhizosphere by genetically modified Streptomyces spp. Five Streptomyces strains, strongly inhibiting in vitro the major soil-borne pathogen of horticultural crops, Sclerotinia sclerotiorum, were transformed with pIJ8641 plas...

  5. Investigation of VEGGIE Root Mat

    Science.gov (United States)

    Subbiah, Arun M.

    2013-01-01

    VEGGIE is a plant growth facility that utilizes the phenomenon of capillary action as its primary watering system. A cloth made of Meta Aramid fiber, known as Nomex is used to wick water up from a reservoir to the bottom of the plants roots. This root mat system is intended to be low maintenance with no moving parts and requires minimal crew interface time. Unfortunately, the water wicking rates are inconsistent throughout the plant life cycle, thus causing plants to die. Over-wicking of water occurs toward the beginning of the cycle, while under-wicking occurs toward the middle. This inconsistency of wicking has become a major issue, drastically inhibiting plant growth. The primary objective is to determine the root cause of the inconsistent wicking through experimental testing. Suspect causes for the capillary water column to break include: a vacuum effect due to a negative pressure gradient in the water reservoir, contamination of material due to minerals in water and back wash from plant fertilizer, induced air bubbles while using syringe refill method, and material limitations of Nomex's ability to absorb and retain water. Experimental testing will be conducted to systematically determine the cause of under and over-wicking. Pressure gages will be used to determine pressure drop during the course of the plant life cycle and during the water refill process. A debubbler device will be connected to a root mat in order to equalize pressure inside the reservoir. Moisture and evaporation tests will simultaneously be implemented to observe moisture content and wicking rates over the course of a plant cycle. Water retention tests will be performed using strips of Nomex to determine materials wicking rates, porosity, and absorptivity. Through these experimental tests, we will have a better understanding of material properties of Nomex, as well as determine the root cause of water column breakage. With consistent test results, a forward plan can be achieved to resolve

  6. Biological control of corky root in tomato.

    Science.gov (United States)

    Fiume, G; Fiume, F

    2008-01-01

    Corky root caused by Pyrenochaeta lycopersici (Schneider et Gerlach) is one of the most important soil borne fungal pathogens which develops in the soils, causing diseases in different crops. The research was carried out to evaluate the effectiveness of the biological control of corky root on tomato. Biological control was performed by using Trichoderma viride Pers. 18/17 SS, Streptomyces spp. AtB42 and Bacillus subtilis M51 PI. According to present and future regulations on the use of chemical fungicides and considering that treatments must avoids environmental pollution, the main object of this research was to find alternative strategies by using biocontrol agents against P. lycopersici that affect tomato plants. In laboratory, the effectiveness of T. viride 18/17 SS, Streptomyces spp. AtB42 and B. subtilis M51 PI to control P. lycopersici were studied. In greenhouse, the research was carried out comparing the following treatments: 1) untreated control; 2) T. viride 18/17 SS; 3) Streptomyces spp. AtB42; 4) B. subtilis M51 PI. Roots of plants of tomato H3028 Hazera were treated with the antagonist suspensions just prior of transplant. Treatments were repeated about 2 months after, with the same suspensions sprayed on the soil to the plant collar. In dual culture, the inhibition of P. lycopersici ranged up to 81.2% (caused from T. viride 18/17 SS), 75.6% (from Streptomyces spp. AtB42) and 66.8% (from B. subtilis M51 PI). In greenhouse trials, with regard to corky root symptoms, all treated plots showed signifycative differences compared to untreated. T. viride gave the better results followed by Streptomyces spp. and then by B. subtilis. The fungus antagonist showed good root surface competence such as demonstrated its persistence on the roots surface of the tomato plants whose roots were treated with T. viride 18/17 SS up to 2 months before.

  7. Effects of Tomato Root Exudates on Meloidogyne incognita.

    Directory of Open Access Journals (Sweden)

    Guodong Yang

    Full Text Available Plant root exudates affect root-knot nematodes egg hatch. Chemicals in root exudates can attract nematodes to the roots or result in repellence, motility inhibition or even death. However, until recently little was known about the relationship between tomato root exudates chemicals and root-knot nematodes. In this study, root exudates were extracted from three tomato rootstocks with varying levels of nematode resistance: Baliya (highly resistant, HR, RS2 (moderately resistant, MR and L-402 (highly susceptible, T. The effects of the root exudates on Meloidogyne incognita (M. incognita egg hatch, survival and chemotaxis of second-stage juveniles (J2 were explored. The composition of the root exudates was analysed by gas chromatography/mass spectrometry (GC/MS prior to and following M. incognita inoculation. Four compounds in root exudates were selected for further analysis and their allopathic effect on M. incognita were investigated. Root exudates from each tomato rootstocks (HR, MR and T strains suppressed M. incognita egg hatch and increased J2 mortality, with the highest rate being observed in the exudates from the HR plants. Exudate from HR variety also repelled M. incognita J2 while that of the susceptible plant, T, was demonstrated to be attractive. The relative amount of esters and phenol compounds in root exudates from HR and MR tomato rootstocks increased notably after inoculation. Four compounds, 2,6-Di-tert-butyl-p-cresol, L-ascorbyl 2,6-dipalmitate, dibutyl phthalate and dimethyl phthalate increased significantly after inoculation. The egg hatch of M. incognita was suppressed by each of the compound. L-ascorbyl 2,6-dipalmitate showed the most notable effect in a concentration-dependent manner. All four compounds were associated with increased J2 mortality. The greatest effect was observed with dimethyl phthalate at 2 mmol·L-1. Dibutyl phthalate was the only compound observed to repel M. incognita J2 with no effect being detected in

  8. Proteomic and metabolomic analyses of soybean root tips under flooding stress.

    Science.gov (United States)

    Komatsu, Setsuko; Nakamura, Takuji; Sugimoto, Yurie; Sakamoto, Kazunori

    2014-01-01

    Flooding is one of the serious problems for soybean plants because it inhibits growth. Proteomic and metabolomic techniques were used to determine whether proteins and metabolites are altered in the root tips of soybeans under flooding stress. Two-day-old soybean plants were flooded for 2 days, and proteins and metabolites were extracted from root tips. Flooding-responsive proteins were identified using two-dimensional- or SDS-polyacrylamide gel electrophoresis- based proteomics techniques. Using both techniques, 172 proteins increased and 105 proteins decreased in abundance in the root tips of flood-stressed soybean. The abundance of methionine synthase, heat shock cognate protein, urease, and phosphoenol pyruvate carboxylase was significantly increased by flooding stress. Furthermore, 73 flooding-responsive metabolites were identified using capillary electrophoresis-mass spectrometry. The levels of gamma-aminobutyric acid, glycine, NADH2, and phosphoenol pyruvate were increased by flooding stress. Taken together, these results suggest that synthesis of phosphoenol pyruvate by way of oxaloacetate produced in the tricarboxylic acid cycle is activated in soybean root tips in response to flooding stress, and that flooding stress also leads to modulation of the urea cycle in the root tips.

  9. Antifungal activity of root, bark, leaf and soil extracts of Androstachys ...

    African Journals Online (AJOL)

    Extracts of leaf, root, soil and bark of Androstachys johnsonii Prain (commonly called Lembobo ironwood) screened for antifungal activity had a significant inhibitory effect on the most of fungi tested in this investigation. Of the four fungi tested in the present study Fusarium solani was significantly inhibited by all extracts (that ...

  10. Elevated CO2 plus chronic warming reduce nitrogen uptake and levels or activities of nitrogen-uptake and -assimilatory proteins in tomato roots.

    Science.gov (United States)

    Jayawardena, Dileepa M; Heckathorn, Scott A; Bista, Deepesh R; Mishra, Sasmita; Boldt, Jennifer K; Krause, Charles R

    2017-03-01

    Atmospheric CO 2 enrichment is expected to often benefit plant growth, despite causing global warming and nitrogen (N) dilution in plants. Most plants primarily procure N as inorganic nitrate (NO 3 - ) or ammonium (NH 4 + ), using membrane-localized transport proteins in roots, which are key targets for improving N use. Although interactive effects of elevated CO 2 , chronic warming and N form on N relations are expected, these have not been studied. In this study, tomato (Solanum lycopersicum) plants were grown at two levels of CO 2 (400 or 700 ppm) and two temperature regimes (30 or 37°C), with NO 3 - or NH 4 + as the N source. Elevated CO 2 plus chronic warming severely inhibited plant growth, regardless of N form, while individually they had smaller effects on growth. Although %N in roots was similar among all treatments, elevated CO 2 plus warming decreased (1) N-uptake rate by roots, (2) total protein concentration in roots, indicating an inhibition of N assimilation and (3) shoot %N, indicating a potential inhibition of N translocation from roots to shoots. Under elevated CO 2 plus warming, reduced NO 3 - -uptake rate per g root was correlated with a decrease in the concentration of NO 3 - -uptake proteins per g root, reduced NH 4 + uptake was correlated with decreased activity of NH 4 + -uptake proteins and reduced N assimilation was correlated with decreased concentration of N-assimilatory proteins. These results indicate that elevated CO 2 and chronic warming can act synergistically to decrease plant N uptake and assimilation; hence, future global warming may decrease both plant growth and food quality (%N). © 2016 Scandinavian Plant Physiology Society.

  11. [Influence of exogenous gamma-aminobutyric acid (GABA) on GABA metabolism and amino acid contents in roots of melon seedling under hypoxia stress].

    Science.gov (United States)

    Wang, Chun-Yan; Li, Jing-Rui; Xia, Qing-Ping; Wu, Xiao-Lei; Gao, Hong-Bo

    2014-07-01

    This paper investigated the influence of gamma-aminobutyric acid (GABA) on GABA metabolism and amino acid content under hypoxia stress by accurately controlling the level of dissolved oxygen in hydroponics, using the roots of melon 'Xiyu 1' seedlings as the test material. The results showed that compared with the control, the growth of roots was inhibited seriously under hypoxia stress. Meanwhile, the hypoxia-treated roots had significantly higher activities of glutamate decarboxylase (GAD), glutamate dehydrogenase (GDH), glutamate synthase (GOGAT), glutamine synthetase (GS), alanine aminotransferase (ALT), aspartate aminotransferase (AST) as well as the contents of GABA, pyruvic acid, alanine (Ala) and aspartic acid (Asp). But the contents of glutamic acid (Glu) and alpha-keto glutaric acid in roots under hypoxia stress was obviously lower than those of the control. Exogenous treatment with GABA alleviated the inhibition effect of hypoxia stress on root growth, which was accompanied by an increase in the contents of endogenous GABA, Glu, alpha-keto glutaric acid and Asp. Furthermore, under hypoxia stress, the activities of GAD, GDH, GOGAT, GS, ALT, AST as well as the contents of pyruvic acid and Ala significantly decreased in roots treated with GABA. However, adding GABA and viny-gamma-aminobutyric acid (VGB) reduced the alleviation effect of GABA on melon seedlings under hypoxia stress. The results suggested that absorption of GABA by roots could alleviate the injury of hypoxia stress to melon seedlings. This meant that GABA treatment allows the normal physiological metabolism under hypoxia by inhibiting the GAD activity through feedback and maintaining higher Glu content as well as the bal- ance of carbon and nitrogen.

  12. Fagopyrum esculentum Alters Its Root Exudation after Amaranthus retroflexus Recognition and Suppresses Weed Growth.

    Science.gov (United States)

    Gfeller, Aurélie; Glauser, Gaétan; Etter, Clément; Signarbieux, Constant; Wirth, Judith

    2018-01-01

    Weed control by crops through growth suppressive root exudates is a promising alternative to herbicides. Buckwheat ( Fagopyrum esculentum ) is known for its weed suppression and redroot pigweed ( Amaranthus retroflexus ) control is probably partly due to allelopathic root exudates. This work studies whether other weeds are also suppressed by buckwheat and if the presence of weeds is necessary to induce growth repression. Buckwheat and different weeds were co-cultivated in soil, separating roots by a mesh allowing to study effects due to diffusion. Buckwheat suppressed growth of pigweed, goosefoot and barnyard grass by 53, 42, and 77% respectively without physical root interactions, probably through allelopathic compounds. Root exudates were obtained from sand cultures of buckwheat (BK), pigweed (P), and a buckwheat/pigweed mixed culture (BK-P). BK-P root exudates inhibited pigweed root growth by 49%. Characterization of root exudates by UHPLC-HRMS and principal component analysis revealed that BK and BK-P had a different metabolic profile suggesting that buckwheat changes its root exudation in the presence of pigweed indicating heterospecific recognition. Among the 15 different markers, which were more abundant in BK-P, tryptophan was identified and four others were tentatively identified. Our findings might contribute to the selection of crops with weed suppressive effects.

  13. Effect of topical alendronate on root resorption of dried replanted dog teeth.

    Science.gov (United States)

    Levin, L; Bryson, E C; Caplan, D; Trope, M

    2001-06-01

    Alendronate (ALN) is a third generation bisphosphonate with demonstrated osteoclast inhibitory activity that may slow down the resorptive process after severe traumatic injuries. Eighty-two premolar roots of five mongrel dogs were endodontically treated and restored, extracted and treated as follows: 70 roots were bench dried for either 40 or 60 min. Thirty-eight of these roots were then soaked for 5 min in a 1 mM solution of ALN in Hanks' Balanced Salt Solution (HBSS) and replanted. Thirty-two roots were soaked for 5 min in HBSS and replanted. In the remaining 12 roots which were not exposed to the bench drying procedure, a 0.5 mM deep lingual mid-root cemental defect was made. Six of these roots were soaked in a 1 mM solution of ALN in HBSS for 5 min and replanted. The other six roots were soaked for 5 min in HBSS and replanted. Historical negative and positive controls were used from similarly treated teeth in our previous studies. After 4 months the dogs were killed and the roots prepared for histological evaluation. Five-microm-thick cross-sections of the root and surrounding tissue taken every 70 microm were evaluated for healing according to the criteria of Andreasen. In the 12 roots with cemental defects, healing with cementum of the damaged root surface was evaluated. In addition, residual root mass was also measured to determine the extent of root structure loss for each soaking method. Cemental healing took place in all 12 artificially damaged roots, indicating that these soaking media did not inhibit cementogenesis. The alendronate-soaked roots had statistically significantly more healing than the roots soaked in HBSS without alendronate. This improvement in healing was seen in all dogs except one and in all teeth except the first premolar. Soaking in alendronate also resulted in significantly less loss in root mass due to resorption compared to those teeth soaked in HBSS without alendronate.

  14. IAA oxidase activity in relation to adventitious root formation on stem cuttings of some forest tree species. [Salix tetrasperma, Populus Robusta, Hibiscus rosa-sinensis, Eucalyptus citriodora

    Energy Technology Data Exchange (ETDEWEB)

    Bansal, M.P.; Nanda, K.K.

    1981-01-01

    In rooting tests with stem cuttings, IAA oxidase activity was found to be very high in Salix tetrasperma and Populus 'Robusta' both of which rooted profusely, less in Hibiscus rosa-sinensis which rooted but weakly and insignificant in Eucalyptus citriodora, which did not root at all. Proteins extracted from the stem cuttings of E. citriodora inhibited IAA oxidase activity, and also root formation on hypocotyl cuttings of Phaseolus mungo.

  15. Chromate and phosphate inhibited each other's uptake and translocation in arsenic hyperaccumulator Pteris vittata L

    International Nuclear Information System (INIS)

    Oliveira, Letúzia M. de; Lessl, Jason T.; Gress, Julia; Tisarum, Rujira; Guilherme, Luiz R.G.; Ma, Lena Q.

    2015-01-01

    We investigated the effects of chromate (CrVI) and phosphate (P) on their uptake and translocation in As-hyperaccumulator Pteris vittata (PV). Plants were exposed to 1) 0.10 mM CrVI and 0, 0.25, 1.25, or 2.50 mM P or 2) 0.25 mM P and 0, 0.50, 2.5 or 5.0 mM CrVI for 24 h in hydroponics. PV accumulated 2919 mg/kg Cr in the roots at CrVI 0.10 , and 5100 and 3500 mg/kg P in the fronds and roots at P 0.25 . When co-present, CrVI and P inhibited each other's uptake in PV. Increasing P concentrations reduced Cr root concentrations by 62–82% whereas increasing CrVI concentrations reduced frond P concentrations by 52–59% but increased root P concentrations by 11–15%. Chromate reduced P transport, with more P being accumulated in PV roots. Though CrVI was supplied, 64−78% and 92−93% CrIII were in PV fronds and roots. Based on X-ray diffraction, Cr 2 O 3 was detected in the roots confirming CrVI reduction to CrIII by PV. In short, CrVI and P inhibited each other in uptake and translocation by PV, and CrVI reduction to CrIII in PV roots served as its detoxification mechanism. The finding helps to understand the interactions of P and Cr during their uptake in PV. - Highlights: • Phosphate and CrVI inhibited each other in uptake and translocation by Pteris vittata. • P. vittata was more efficient in CrVI uptake than CrIII, but little Cr being translocated to the fronds. • CrVI was provided in the media, but 64–78% and 92–93% CrIII were in the fronds and roots of P. vittata. • CrVI was taken up by P. vittata and reduced to CrIII in the roots possibly as Cr 2 O 3 . - Pteris vittata was efficient in CrVI uptake, concentrating in the roots after reducing to CrIII

  16. Azacytidine and miR156 promote rooting in adult but not in juvenile Arabidopsis tissues.

    Science.gov (United States)

    Massoumi, Mehdi; Krens, Frans A; Visser, Richard G F; De Klerk, Geert-Jan M

    2017-01-01

    Poor adventitious root (AR) formation is a major obstacle in micropropagation and conventional vegetative propagation of many crops. It is affected by many endogenous and exogenous factors. With respect to endogenous factors, the phase change from juvenile to adult has a major influence on AR formation and rooting is usually much reduced or even fully inhibited in adult tissues. It has been reported that the phase change is characterized by an increase in DNA-methylation and a decrease in the expression of microRNA156 (miR156). In this paper, we examined the effect of azacytidine (AzaC) and miR156 on AR formation in adult and juvenile Arabidopsis tissues. To identify the ontogenetic state researchers have used flowering or leaf morphology. We have used the rootability which allows - in contrast with both other characteristics- to examine the ontogenetic state at the cellular level. Overexpression of miR156 promoted only the rooting of adult tissues indicating that the phase change-associated loss in tissues' competence to develop ARs is also under the control of miR156. Azacytidine inhibits DNA methylation during DNA replication. Azacytidine treatment also promoted AR formation in nonjuvenile tissues but had no or little effect in juvenile tissues. Its addition during seedling growth (by which all tissues become hypomethylated) or during the rooting treatment (by which only those cells become hypomethylated that are generated after taking the explant) are both effective in the promotion of rooting. An AzaC treatment may be useful in tissue culture for crops that are recalcitrant to root. Copyright © 2016 Elsevier GmbH. All rights reserved.

  17. Evaluation of the antioxidant activity of root extract of pepper fruit (Dennetia tripetala), and it's potential for the inhibition of lipid peroxidation.

    Science.gov (United States)

    Okolie, Ngozi Paulinus; Falodun, Abiodun; Davids, Oluseyi

    2014-01-01

    The antioxidant properties of ethanolic root extract of pepper fruit (Donnetia tripetala), and its effect on lipid peroxidation of some fresh beef tissues during frozen storage were investigated. The antioxidant parameters were assessed using standard methods, while malondialdehyde levels of different fresh beef tissue sections treated with the extract prior to freezing, were estimated in a colorimetric reaction with thiobarbituric acid. The H2O2-scavenging ability of the extract was similar to that of ascorbic acid, with a maximum scavenging power of 55.61 ±4.98%, and an IC50 value of 86µg/ml. The extract exhibited a concentration-dependent ferric ion-reducing power, although this was significantly lower relative to that of the ascorbic acid (p capacity of the extract to inhibit lipid peroxidation in frozen heart muscle slices was significantly higher than that of vitamin C (p extract of D. tripetala is rich in antioxidants which can be applied to meat preservation during refrigerated storage.

  18. In vitro antimycobacterial and antilegionella activity of licochalcone A from Chinese licorice roots

    DEFF Research Database (Denmark)

    Friis-Møller, Alice; Chen, Ming; Fuursted, Kurt

    2002-01-01

    Licochalcone A, extracted and purified from Chinese licorice roots, showed in vitro inhibitory effect on human pathogenic Mycobacteria species and Legionella species. M. tuberculosis, M. bovis and BCG were inhibited by < 20 mg/l licochalcone A, whereas all non- M. tuberculosis complex species wer...

  19. MPK6 controls H2 O2-induced root elongation by mediating Ca2+ influx across the plasma membrane of root cells in Arabidopsis seedlings.

    Science.gov (United States)

    Han, Shuan; Fang, Lin; Ren, Xuejian; Wang, Wenle; Jiang, Jing

    2015-01-01

    Mitogen-activated protein kinases (MPKs) play critical roles in signalling and growth, and Ca(2+) and H2 O2 control plant growth processes associated with abscisic acid (ABA). However, it remains unclear how MPKs are involved in H2 O2 - and Ca(2+) -mediated root elongation. Root elongation in seedlings of the loss-of-function mutant Atmpk6 (Arabidopsis thaliana MPK6) was less sensitive to moderate H2 O2 or ABA than that in wild-type (WT) plants. The enhanced elongation was a result of root cell expansion. This effect disappeared when ABA-induced H2 O2 accumulation or the cytosolic Ca(2+) increase were defective. Molecular and biochemical evidence showed that increased expression of the cell wall peroxidase PRX34 in Atmpk6 root cells enhanced apoplastic H2 O2 generation; this promoted a cytosolic Ca(2+) increase and Ca(2+) influx across the plasma membrane. The plasma membrane damage caused by high levels of H2 O2 was ameliorated in a Ca(2+) -dependent manner. These results suggested that there was intensified PRX34-mediated H2 O2 generation in the apoplast and increased Ca(2+) flux into the cytosol of Atmpk6 root cells; that is, the spatial separation of apoplastic H2 O2 from cytosolic Ca(2+) in root cells prevented H2 O2 -induced inhibition of root elongation in Atmpk6 seedlings. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  20. Effects of ionizing radiation on the hypocotyl-root axis of three species of gossypium

    International Nuclear Information System (INIS)

    Reed, J.P.

    1977-01-01

    The hypocotyl-root axis of cotton seedlings grown from irradiated and non-irradiated seeds was investigated using light microscopy and histological techniques. Special emphasis was placed on the pattern of vascular transition. Two patterns of vascular transition in non-irradiated seedlings were found. In Gossypium hirsutum and G. barbadense there are prominent metaxylem bands between the vascular bundles in the hypocotyl. In G. gossypioides there are no bands. The presence or absence of the bands was easily detected using polarized light. The most outstanding effects of radiation were inhibition of lateral root development and alteration of the pattern of vascular transition in seedlings grown from irradiated seeds. The findings suggest that the root apical meristem determines the vascular pattern

  1. Characterization of a chondroitin sulfate hydrogel for nerve root regeneration

    Science.gov (United States)

    Conovaloff, Aaron; Panitch, Alyssa

    2011-10-01

    Brachial plexus injury is a serious medical problem that affects many patients annually, with most cases involving damage to the nerve roots. Therefore, a chondroitin sulfate hydrogel was designed to both serve as a scaffold for regenerating root neurons and deliver neurotrophic signals. Capillary electrophoresis showed that chondroitin sulfate has a dissociation constant in the micromolar range with several common neurotrophins, and this was determined to be approximately tenfold stronger than with heparin. It was also revealed that nerve growth factor exhibits a slightly stronger affinity for hyaluronic acid than for chondroitin sulfate. However, E8 chick dorsal root ganglia cultured in the presence of nerve growth factor revealed that ganglia cultured in chondroitin sulfate scaffolds showed more robust growth than those cultured in control gels of hyaluronic acid. It is hypothesized that, despite the stronger affinity of nerve growth factor for hyaluronic acid, chondroitin sulfate serves as a better scaffold for neurite outgrowth, possibly due to inhibition of growth by hyaluronic acid chains.

  2. The Growth of Root Rot Disease on Pepper Seed Applied by Trichoderma Harzianum Inoculum

    Directory of Open Access Journals (Sweden)

    S. Sofian

    2013-06-01

    Full Text Available Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 Root rot disease on pepper caused by Phytophthora capsici is one of the most important diseases on pepper. The using of antagonistic fungus of Trichoderma harzianum as a biological control agent of the pathogen is one of the important alternatives in controlling P. capsici without causing negative effects on the environment. The objectives of the research were to study about the ability of T. harzianum inoculum application in inhibiting the development of root-rot disease, influenced the growth of pepper seed, to studythe effective length time application of T. harzianum inoculum in inhibiting the development of root rot disease, and increased the growth of pepper seedlings. This research was arranged in a completely randomized design, with five treatments of length time application of T. harzianum inoculum i.e. control treatment without applicationtime of T. harzianum inoculum (K, application time of T. harzianum inoculum for 0 week (S0, application time of T. harzianum inoculum for 1 week (S1, application time of T. harzianum inoculum for two weeks (S2, application time of T. harzianum inoculum for three weeks (S3, and application time of T. harzianum inoculum for 4 weeks (S4 before planting. Each treatment was repeated15 times. The observed parameterswere disease percentage, the inhibition of antagonistic fungus, disease infection rate, plant height, number of leaves, wet and dry weight of plant, stem and leaves on pepper seed, and P. capsici population density. The result showed that application time of T. harzianum inoculumfor 4 weeks (S4 before planting is the most effective time in inhibiting the development of root rot disease than the other treatment sand also had significant effect on increasing the growth of pepper seed. The antagonism test showed that T. harzianum could inhibit P. capsiciin vitro. This result proves that application time of T. harzianum inoculums

  3. [Behavior of different strains of Staphylococcus aureus against root canal filling cements].

    Science.gov (United States)

    Pumarola, J; Berástegui, E; Canalda, C; Brau, E

    1991-01-01

    The mean goal of this study is the determination of the conduct of 120 strains of Staphylococcus aureus against seven root canal sealers: Traitement Spad, Endométhasone, N2 Universal, AH26 with silver, Diaket-A, Tubli Seal and Sealapex. The agar diffusion test was employed in the determination of its bacterial growth inhibition. The results obtained have demonstrated values very different between the tested strains. Therefore we recommended to employ strains with reference in the investigation of the bacterial growth inhibition in order to repeat equal experimentation conditions.

  4. Characterization and inhibitive study of gel-grown hydroxyapatite crystals at physiological temperature

    Science.gov (United States)

    Parekh, Bharat; Joshi, Mihir; Vaidya, Ashok

    2008-04-01

    Hydroxyapatite is very useful for various biomedical applications, due to its chemical similarity with mineralized bone of human. Hydroxyapatite is also responsible for arthropathy (joint disease). In the present study, the growth of hydroxyapatite crystals was carried out by using single-diffusion gel growth technique in silica hydro gel media, at physiological temperature. The growth of hydroxyapatite crystals under slow and controlled environment in gel medium can be simulated in a simple manner to the growth in human body. The crystals, formed in the Liesegang rings, were characterized by powder XRD, FTIR and dielectric study. The diffusion study is also carried out for the hydroxyapatite crystals using the moving boundary model. The inhibitive influence of various Ayurvedic medicinal plant extracts such as Boswellia serrata gum resin , Tribulus terrestris fruits, Rotula aquatica roots, Boerhaavia diffusa roots and Commiphora wightii, on the growth of hydroxyapatite was studied. Roots of R. aquatica and B. diffusa show some inhibition of the hydroxyapatite crystals in vitro. This preclinical study will be helpful to design the therapy for prevention of hydroxyapatite-based ailments.

  5. Root development during soil genesis: effects of root-root interactions, mycorrhizae, and substrate

    Science.gov (United States)

    Salinas, A.; Zaharescu, D. G.

    2015-12-01

    A major driver of soil formation is the colonization and transformation of rock by plants and associated microbiota. In turn, substrate chemical composition can also influence the capacity for plant colonization and development. In order to better define these relationships, a mesocosm study was set up to analyze the effect mycorrhizal fungi, plant density and rock have on root development, and to determine the effect of root morphology on weathering and soil formation. We hypothesized that plant-plant and plant-fungi interactions have a stronger influence on root architecture and rock weathering than the substrate composition alone. Buffalo grass (Bouteloua dactyloides) was grown in a controlled environment in columns filled with either granular granite, schist, rhyolite or basalt. Each substrate was given two different treatments, including grass-microbes and grass-microbes-mycorrhizae and incubated for 120, 240, and 480 days. Columns were then extracted and analyzed for root morphology, fine fraction, and pore water major element content. Preliminary results showed that plants produced more biomass in rhyolite, followed by schist, basalt, and granite, indicating that substrate composition is an important driver of root development. In support of our hypothesis, mycorrhizae was a strong driver of root development by stimulating length growth, biomass production, and branching. However, average root length and branching also appeared to decrease in response to high plant density, though this trend was only present among roots with mycorrhizal fungi. Interestingly, fine fraction production was negatively correlated with average root thickness and volume. There is also slight evidence indicating that fine fraction production is more related to substrate composition than root morphology, though this data needs to be further analyzed. Our hope is that the results of this study can one day be applied to agricultural research in order to promote the production of crops

  6. Blood, sweat, tears and success of technology transfer long-term controlled-release of herbicides: Root-growth-inhibiting biobarrier technology

    International Nuclear Information System (INIS)

    Van Voris, P.; Cataldo, D.A.; Burton, F.G.; Skeins, W.E.

    1988-01-01

    Through the unique combination of polymers with a herbicidally active dinitroaniline, a cylinderical pellet (9mm long and 9mm in diameter) was developed that continuously releases a herbicide for a period of up to 100 years. Equilibrium concentration of the herbicide in soil adjacent to the pellet and the bioactive lifetime of the device cam be adjusted by changing the size of the pellet; the type of polymer; the type, quality, and quantity of carrier; and/or the concentration and type of dinitroaniline used. Commercial products that have been developed under a Federal Technology Transfer Program that utilize this technology include: (1) ROOT-SHIELD, a root repelling sewer gasket for concrete, clay, and PVC sewer lines, (2) BIOBARRIER, a spun-bonded polypropylene geotextile fabric developed to prevent root growth from invading septic tanks; penetrating under roadways, and along the edge of sidewalks, airport runways, and tennis courts, and for landscaped areas; and (3) ROOT-GUARD, a plastic drip irrigation emitter designed to protect buried drip irrigation systems from being plugged by roots. 17 refs., 4 figs., 6 tabs

  7. SHB1/HY1 Alleviates Excess Boron Stress by Increasing BOR4 Expression Level and Maintaining Boron Homeostasis in Arabidopsis Roots

    Directory of Open Access Journals (Sweden)

    Qiang Lv

    2017-05-01

    Full Text Available Boron is an essential mineral nutrient for higher plant growth and development. However, excessive amounts of boron can be toxic. Here, we report on the characterization of an Arabidopsis mutant, shb1 (sensitive to high-level of boron 1, which exhibits hypersensitivity to excessive boron in roots. Positional cloning demonstrated that the shb1 mutant bears a point mutation in a gene encoding a heme oxygenase 1 (HO1 corresponding to the HY1 gene involved in photomorphogenesis. The transcription level of the SHB1/HY1 gene in roots is up-regulated under excessive boron stimulation. Either overexpressing SHB1/HY1 or applying the HO1 inducer hematin reduces boron accumulation in roots and confers high boron tolerance. Furthermore, carbon monoxide and bilirubin, catalytic products of HO1, partially rescue the boron toxicity-induced inhibition of primary root growth in shb1. Additionally, the mRNA level of BOR4, a boron efflux transporter, is reduced in shb1 roots with high levels of boron supplementation, and hematin cannot relieve the boron toxicity-induced root inhibition in bor4 mutants. Taken together, our study reveals that HO1 acts via its catalytic by-products to promote tolerance of excessive boron by up-regulating the transcription of the BOR4 gene and therefore promoting the exclusion of excessive boron in root cells.

  8. Differential effects of auxin polar transport inhibitors on rooting in some Crassulaceae species

    Directory of Open Access Journals (Sweden)

    Marian Saniewski

    2014-07-01

    Full Text Available Effects of auxin polar transport inhibitors, 2,3,5-triio-dobenzoic acid (TIBA, 1-N-naphthylphthalamic acid (NPA and methyl 2-chloro-9-hydroxyfluorene-9-carboxylate (morphactin IT 3456, as a lanolin paste, on root formation in cuttings of some species of Crassulaceae, such as Bryophyllum daigremontianum, B. calycinum, Kalanchoe blossfeldiana and K. tubiflora, were studied. Cuttings of these plants were easily rooted in water without any treatment. TIBA and morphactin IT 3456 completely inhibited root formation in the cuttings of these plants but NPA did not when these inhibitors were applied around the stem below the leaves. When TIBA and morphactin were applied around the stem near the top, but leaves were present below the treatment, the root formation was observed in B. calycinum and K. blossfeldiana but in a smaller degree than in control cuttings. These results strongly suggest that endogenous auxin is required for root formation in cuttings of Crassulaceae plants. The differential mode of action of NPA is discussed together with its effect on auxin polar transport.

  9. Antioxidant, antimicrobial, toxicity and analgesic properties of ethanol extract of Solena amplexicaulis root

    Directory of Open Access Journals (Sweden)

    Md Golam Kabir

    2014-01-01

    Full Text Available BACKGROUND: This study was subjected to investigate different pharmacological properties of ethanol extract ofSolena amplexicaulis root. RESULTS: The extract contains flavonoid, alkaloid, saponin and steroid compounds. The extract exhibited excellent antioxidant activity in DPPH radical scavenging activity. The extract also showed potent activity in brine shrimp lethality bioassay. The LC50 value was found to 44.677 µg/ml. The extract showed better anti-bacterial activity against gram-negative bacteria. In antifungal assay, the maximum 79.31% of anti-mycotic activity was observed against Aspergillus ochraceus while minimum 44.2% against Rhizopus oryzae. MIC value ranged between 1500 - 3000 µg/ml. The extract was found moderately toxic with a 24-hr LD50 value of 81.47 mg/kg in Swiss albino mice. The degree of inhibition by the ethanolic extract of the root was found less than that of standard analgesic drug diclofenac sodium. The extract also showed moderate anti-inflammatory and antinociceptive activity and anti-diabetic property. Reducing power of the extract was comparable with standard ascorbic acid. Moderate in vitro thrombolytic activity, lipid peroxidation inhibition property, metal chelating ability and stress-protective activity was also observed. CONCLUSION: Ethanol extract of Solena amplexicaulis root can be valuable for treatment of different diseases.

  10. Rooting gene trees without outgroups: EP rooting.

    Science.gov (United States)

    Sinsheimer, Janet S; Little, Roderick J A; Lake, James A

    2012-01-01

    Gene sequences are routinely used to determine the topologies of unrooted phylogenetic trees, but many of the most important questions in evolution require knowing both the topologies and the roots of trees. However, general algorithms for calculating rooted trees from gene and genomic sequences in the absence of gene paralogs are few. Using the principles of evolutionary parsimony (EP) (Lake JA. 1987a. A rate-independent technique for analysis of nucleic acid sequences: evolutionary parsimony. Mol Biol Evol. 4:167-181) and its extensions (Cavender, J. 1989. Mechanized derivation of linear invariants. Mol Biol Evol. 6:301-316; Nguyen T, Speed TP. 1992. A derivation of all linear invariants for a nonbalanced transversion model. J Mol Evol. 35:60-76), we explicitly enumerate all linear invariants that solely contain rooting information and derive algorithms for rooting gene trees directly from gene and genomic sequences. These new EP linear rooting invariants allow one to determine rooted trees, even in the complete absence of outgroups and gene paralogs. EP rooting invariants are explicitly derived for three taxon trees, and rules for their extension to four or more taxa are provided. The method is demonstrated using 18S ribosomal DNA to illustrate how the new animal phylogeny (Aguinaldo AMA et al. 1997. Evidence for a clade of nematodes, arthropods, and other moulting animals. Nature 387:489-493; Lake JA. 1990. Origin of the metazoa. Proc Natl Acad Sci USA 87:763-766) may be rooted directly from sequences, even when they are short and paralogs are unavailable. These results are consistent with the current root (Philippe H et al. 2011. Acoelomorph flatworms are deuterostomes related to Xenoturbella. Nature 470:255-260).

  11. Solanum paniculatum root extract reduces diarrhea in rats

    Directory of Open Access Journals (Sweden)

    Jonh A.B. Tenório

    Full Text Available Abstract Solanum paniculatum L., Solanaceae, locally known as "jurubeba", is widely used in Brazil for culinary purposes, and in folk medicine to treat of diverse disorder including gastric dysfunctions. In this study we investigated the antidiarrheal activity of S. paniculatum roots extract in rats at different concentrations (125, 250 and 500 mg/kg, p.o using different experimental models such as castor oil-induced diarrhea, enteropooling and gastrointestinal motility, determined by in vivo experimental models. The major compound of root extract was characterized as chlorogenic acid based in the IR, 1D and 2D NMR analysis. All the extract doses achieved antidiarrheal potency, as indicated by reduced weight of feces in castor oil-induced diarrhea, decreased intestinal motility and significantly inhibited castor oil-induced enteropooling compared to the vehicle group. The highest dose (500 mg/kg produced greater anti-motility effect and better reduction of enteropooling, similar to the reference drug Loperamide (5 mg/kg. Extract from S. paniculatum L. roots had antidiarrheal activity, as shown by the lower weight of the feces as well as decrease in the accumulation of intestinal fluid and slower transit, justifying the traditional use of plant for diarrhea.

  12. Retinal glia promote dorsal root ganglion axon regeneration.

    Directory of Open Access Journals (Sweden)

    Barbara Lorber

    Full Text Available Axon regeneration in the adult central nervous system (CNS is limited by several factors including a lack of neurotrophic support. Recent studies have shown that glia from the adult rat CNS, specifically retinal astrocytes and Müller glia, can promote regeneration of retinal ganglion cell axons. In the present study we investigated whether retinal glia also exert a growth promoting effect outside the visual system. We found that retinal glial conditioned medium significantly enhanced neurite growth and branching of adult rat dorsal root ganglion neurons (DRG in culture. Furthermore, transplantation of retinal glia significantly enhanced regeneration of DRG axons past the dorsal root entry zone after root crush in adult rats. To identify the factors that mediate the growth promoting effects of retinal glia, mass spectrometric analysis of retinal glial conditioned medium was performed. Apolipoprotein E and secreted protein acidic and rich in cysteine (SPARC were found to be present in high abundance, a finding further confirmed by western blotting. Inhibition of Apolipoprotein E and SPARC significantly reduced the neuritogenic effects of retinal glial conditioned medium on DRG in culture, suggesting that Apolipoprotein E and SPARC are the major mediators of this regenerative response.

  13. RootJS: Node.js Bindings for ROOT 6

    Science.gov (United States)

    Beffart, Theo; Früh, Maximilian; Haas, Christoph; Rajgopal, Sachin; Schwabe, Jonas; Wolff, Christoph; Szuba, Marek

    2017-10-01

    We present rootJS, an interface making it possible to seamlessly integrate ROOT 6 into applications written for Node.js, the JavaScript runtime platform increasingly commonly used to create high-performance Web applications. ROOT features can be called both directly from Node.js code and by JIT-compiling C++ macros. All rootJS methods are invoked asynchronously and support callback functions, allowing non-blocking operation of Node.js applications using them. Last but not least, our bindings have been designed to platform-independent and should therefore work on all systems supporting both ROOT 6 and Node.js. Thanks to rootJS it is now possible to create ROOT-aware Web applications taking full advantage of the high performance and extensive capabilities of Node.js. Examples include platforms for the quality assurance of acquired, reconstructed or simulated data, book-keeping and e-log systems, and even Web browser-based data visualisation and analysis.

  14. Evaluation of bacterial leakage of four root- end filling materials: Gray Pro Root MTA, White Pro Root MTA, Root MTA and Portland Cement (type I

    Directory of Open Access Journals (Sweden)

    Zarabian M.

    2005-07-01

    Full Text Available Background and Aim: Today several materials have been used for root- end filling in endodontic surgery. Optimal properties of Pro Root MTA in in-vitro and in-vivo studies has been proven. On the other hand, based on some studies, Root MTA (Iranian Pro Root MTA and Portland cement are similar to Pro Root MTA in physical and biologic properties. The aim of this study was to evaluate bacterial leakage (amount and mean leakage time of four root- end filling materials. Materials and Methods: In this experimental in-vitro study, seventy six extracted single- rooted human teeth were randomly divided into six groups for root-end filling with gray Pro Root MTA, white Pro Root MTA, Root MTA (Iranian Pro Root MTA, Portland Cement (type I and positive and negative control groups. Root canals were instrumented using the step- back technique. Root- end filling materials were placed in 3mm ultra sonic retro preparations. Samples and microleakage model system were sterilized in autoclave. The apical 3-4 mm of the roots were immersed in phenol red with 3% lactose broth culture medium. The coronal access of each specimen was inoculated every 24h with a suspension of Streptococcus sanguis (ATCC 10556. Culture media were observed every 24h for colour change indicating bacterial contamination for 60 days. Statistical analysis was performed using log- rank test with P<0.05 as the limit of significance. Results: At the end of study 50%, 56.25%, 56.25% and 50% of specimens filled with Gray Pro Root MTA, White Pro Root MTA. Root MTA and Portland Cement (type I had evidence of leakage respectively. The mean leakage time was 37.19±6.29, 36.44±5.81, 37.69±5.97 and 34.81±6.67 days respectively. Statistical analysis of data showed no significant difference among the leakage (amount and mean leakage time of the four tested root- end filling materials (P=0.9958. Conclusion: Based on the results of this study, there were no significant differences in leakage among the four

  15. Water-soluble constituents of the root barks of Fraxinus rhynchophylla (Chinese drug Qinpi).

    Science.gov (United States)

    Xiao, Kai; Song, Qing-Hong; Zhang, Shu-Wei; Xuan, Li-Jiang

    2008-01-01

    Chemical studies on the roots of Fraxinus rhynchophylla led to the isolation of fraxisecoside (1), a novel coumarin-secoiridoid hybrid glycoside, namely, fraxetin-8-O-[11'-methyl-oleosidyl-(7'-->6'')]-beta-D-glucopyranoside and 14 known compounds. Their structures were elucidated based on chemical evidence and spectroscopic analysis, including extensive 2D NMR methods. Compound 2 was first isolated as a pure compound. Compound 1 exhibited moderate PTP1B inhibition activity. Compounds 1 and 2 showed inhibition activity against B- and T-cell proliferation, without cytotoxicity.

  16. Functional Analysis of the Arabidopsis thaliana CDPK-Related Kinase Family: AtCRK1 Regulates Responses to Continuous Light

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    Abu Imran Baba

    2018-04-01

    Full Text Available The Calcium-Dependent Protein Kinase (CDPK-Related Kinase family (CRKs consists of eight members in Arabidopsis. Recently, AtCRK5 was shown to play a direct role in the regulation of root gravitropic response involving polar auxin transport (PAT. However, limited information is available about the function of the other AtCRK genes. Here, we report a comparative analysis of the Arabidopsis CRK genes, including transcription regulation, intracellular localization, and biological function. AtCRK transcripts were detectable in all organs tested and a considerable variation in transcript levels was detected among them. Most AtCRK proteins localized at the plasma membrane as revealed by microscopic analysis of 35S::cCRK-GFP (Green Fluorescence Protein expressing plants or protoplasts. Interestingly, 35S::cCRK1-GFP and 35S::cCRK7-GFP had a dual localization pattern which was associated with plasma membrane and endomembrane structures, as well. Analysis of T-DNA insertion mutants revealed that AtCRK genes are important for root growth and control of gravitropic responses in roots and hypocotyls. While Atcrk mutants were indistinguishable from wild type plants in short days, Atcrk1-1 mutant had serious growth defects under continuous illumination. Semi-dwarf phenotype of Atcrk1-1 was accompanied with chlorophyll depletion, disturbed photosynthesis, accumulation of singlet oxygen, and enhanced cell death in photosynthetic tissues. AtCRK1 is therefore important to maintain cellular homeostasis during continuous illumination.

  17. Root proliferation in decaying roots and old root channels: A nutrient conservation mechanism in oligotrophic mangrove forests?

    Science.gov (United States)

    McKee, K.L.

    2001-01-01

    1. In oligotrophic habitats, proliferation of roots in nutrient-rich microsites may contribute to overall nutrient conservation by plants. Peat-based soils on mangrove islands in Belize are characterized by the presence of decaying roots and numerous old root channels (0.1-3.5 cm diameter) that become filled with living and highly branched roots of Rhizophora mangle and Avicennia germinans. The objectives of this study were to quantify the proliferation of roots in these microsites and to determine what causes this response. 2. Channels formed by the refractory remains of mangrove roots accounted for only 1-2% of total soil volume, but the proportion of roots found within channels varied from 9 to 24% of total live mass. Successive generations of roots growing inside increasingly smaller root channels were also found. 3. When artificial channels constructed of PVC pipe were buried in the peat for 2 years, those filled with nutrient-rich organic matter had six times more roots than empty or sand-filled channels, indicating a response to greater nutrient availability rather than to greater space or less impedance to root growth. 4. Root proliferation inside decaying roots may improve recovery of nutrients released from decomposing tissues before they can be leached or immobilized in this intertidal environment. Greatest root proliferation in channels occurred in interior forest zones characterized by greater soil waterlogging, which suggests that this may be a strategy for nutrient capture that minimizes oxygen losses from the whole root system. 5. Improved efficiency of nutrient acquisition at the individual plant level has implications for nutrient economy at the ecosystem level and may explain, in part, how mangroves persist and grow in nutrient-poor environments.

  18. Trichoderma-Induced Acidification Is an Early Trigger for Changes in Arabidopsis Root Growth and Determines Fungal Phytostimulation

    Science.gov (United States)

    Pelagio-Flores, Ramón; Esparza-Reynoso, Saraí; Garnica-Vergara, Amira; López-Bucio, José; Herrera-Estrella, Alfredo

    2017-01-01

    Trichoderma spp. are common rhizosphere inhabitants widely used as biological control agents and their role as plant growth promoting fungi has been established. Although soil pH influences several fungal and plant functional traits such as growth and nutrition, little is known about its influence in rhizospheric or mutualistic interactions. The role of pH in the Trichoderma–Arabidopsis interaction was studied by determining primary root growth and lateral root formation, root meristem status and cell viability, quiescent center (QC) integrity, and auxin inducible gene expression. Primary root growth phenotypes in wild type seedlings and STOP1 mutants allowed identification of a putative root pH sensing pathway likely operating in plant–fungus recognition. Acidification by Trichoderma induced auxin redistribution within Arabidopsis columella root cap cells, causing root tip bending and growth inhibition. Root growth stoppage correlated with decreased cell division and with the loss of QC integrity and cell viability, which were reversed by buffering the medium. In addition, stop1, an Arabidopsis mutant sensitive to low pH, was oversensitive to T. atroviride primary root growth repression, providing genetic evidence that a pH root sensing mechanism reprograms root architecture during the interaction. Our results indicate that root sensing of pH mediates the interaction of Trichoderma with plants. PMID:28567051

  19. The ethylene-inhibitor aminoethoxyvinylglycine restores normal nodulation by Rhizobium leguminosarum biovar. viciae on Vicia sativa subsp. nigra by suppressing the 'Thick and short roots' phenotype.

    Science.gov (United States)

    Zaat, S A; Van Brussel, A A; Tak, T; Lugtenberg, B J; Kijne, J W

    1989-02-01

    Nodulation of Vicia sativa subsp. nigra L. by Rhizobium bacteria is coupled to the development of thick and short roots (Tsr). This root phenotype as well as root-hair induction (Hai) and root-hair deformation (Had) are caused by a factor(s) produced by the bacteria in response to plant flavonoids. When very low inoculum concentrations (0.5-5 bacteria·ml(-1)) were used, V. sativa plants did not develop the Tsr phenotype and became nodulated earlier than plants with Tsr roots. Furthermore, the nodules of these plants were located on the primary root in contrast to nodules on Tsr roots, which were all located at sites of lateral-root emergence. The average numbers of nodules per plant were not significantly different for these two types of nodulation. Root-growth inhibition and Hai, but not Had, could be mimicked by ethephon, and inhibited by aminoethoxyvinylglycine (AVG). Addition of AVG to co-cultures of Vicia sativa and the standard inoculum concentration of 5·10(5) bacteria·ml(-1) suppressed the development of the Tsr phenotype and restored nodulation to the pattern that was observed with very low concentrations of bacteria (0.5-5 bacteria·ml(-1)). The delay in nodulation on Tsr roots appeared to be caused by the fact that nodule meristems did not develop on the primary root, but only on the emerging laterals. The relationship between Tsr, Hai, Had, and nodulation is discussed.

  20. Effect of nickel on the organization of actin filaments in Arabidopsis thaliana primary root cells

    International Nuclear Information System (INIS)

    Goryunova, I.I.; Krasilenko, Yu.A.; Emets, A.I.; Blyum, Ya.B.

    2016-01-01

    The influence of one of the most toxic heavy metals - nickel (Ni 2+ ) - on the organization of actin filaments (microfilaments) of different types of Arabidopsis thaliana (L.) root cells is studied in living cells by the laser scanning microscopy. To visualize microfilaments, the A. thaliana line expressing chimeric gene gfp-fabd2 was used. Ni 2+ leads to a significant inhibition of the growth of the main root and disturbs its morphology, causing the swelling of epidermal cells and inducing a large number of abnormally long root hairs. For the first time, it has been shown that Ni 2+ disturbs the organization of actin filaments in cells, leading to morphological changes of a root as the main organ, being the first exposed to the intoxication by soil pollutants. It is found that the most sensitive to its action are actin filaments of epidermal cells of all growth zones of A. thaliana root

  1. Analyzing Arabidopsis thaliana root proteome provides insights into the molecular bases of enantioselective imazethapyr toxicity

    Science.gov (United States)

    Qian, Haifeng; Lu, Haiping; Ding, Haiyan; Lavoie, Michel; Li, Yali; Liu, Weiping; Fu, Zhengwei

    2015-07-01

    Imazethapyr (IM) is a widely used chiral herbicide that inhibits the synthesis of branched-chain amino acids (BCAAs). IM is thought to exert its toxic effects on amino acid synthesis mainly through inhibition of acetolactate synthase activity, but little is known about the potential effects of IM on other key biochemical pathways. Here, we exposed the model plant Arabidospsis thaliana to trace S- and R-IM enantiomer concentrations and examined IM toxicity effects on the root proteome using iTRAQ. Conventional analyses of root carbohydrates, organic acids, and enzyme activities were also performed. We discovered several previously unknown key biochemical pathways targeted by IM in Arabidospsis. 1,322 and 987 proteins were differentially expressed in response to R- and S-IM treatments, respectively. Bioinformatics and physiological analyses suggested that IM reduced the BCAA tissue content not only by strongly suppressing BCAA synthesis but also by increasing BCAA catabolism. IM also affected sugar and starch metabolism, changed the composition of root cell walls, increased citrate production and exudation, and affected the microbial community structure of the rhizosphere. The present study shed new light on the multiple toxicity mechanisms of a selective herbicide on a model plant.

  2. Anti-ulcerogenic activity of the root bark extract of the African laburnum “Cassia sieberiana” and its effect on the anti-oxidant defence system in rats

    Directory of Open Access Journals (Sweden)

    Nartey Edmund T

    2012-12-01

    Full Text Available Abstract Background Despite the widespread use of roots of Cassia sieberiana in managing several health conditions including gastric ulcer disease, there is little scientific data to support the rational phytotherapeutics as an anti-ulcer agent. This paper reports an evaluation of the in vivo anti-oxidant properties of an aqueous root bark extract of C. sieberiana in experimental gastric ulcer rats in a bid to elucidate its mechanism of action. Methods Fisher 344 (F344 rats received pretreatment of C. sieberiana root bark extract (500, 750, and 1000 mg/kg body wt. for 7 days after which there was induction of gastric injury with absolute ethanol. The mean ulcer index (MUI was calculated and serum total anti-oxidant level determined. Gastric mucosal tissues were prepared and the activity level of the enzymes superoxide dismutase (SOD, catalase (CAT, glutathione peroxidase (GPx and myeloperoxidase (MPO were measured together with the level of lipid hydroperoxides (LPO. Statistical difference between treatment groups was analysed using one-way analysis of variance (ANOVA followed by Dunnett’s post hoc t test. Statistical significance was calculated at P Results The administration of ethanol triggered severe acute gastric ulcer and pretreatment with C. sieberiana root bark extract significantly and dose dependently protected against this effect. The root bark extract also dose dependently and significantly inhibited the ethanol induced decrease in activity levels of the enzymes SOD, CAT and GPx. The extract also inhibited the ethanol-induced decrease in level of serum total anti-oxidant capacity. The increase in ethanol-induced LPO level and MPO activity were also significantly and dose-dependently inhibited by the root bark extract. Conclusions The gastro-cytoprotective effect, inhibition of decrease in activity of gastric anti-oxidant enzymes and MPO as well as the inhibition of gastric LPO level suggests that one of the anti-ulcer mechanisms of

  3. Phytochemical and antifungal activity of anthraquinones and root and leaf extracts of Coccoloba mollis on phytopathogens

    Directory of Open Access Journals (Sweden)

    Iuri Bezerra de Barros

    2011-06-01

    Full Text Available The aim of this work was to study the phytochemical and antifungal activity of anthraquinones and root and leaf extracts of Coccoloba mollis on phytopathogens. The chemical analysis of ethanolic extracts showed a mixture of long-chain hydrocarbons, carboxyl esters and 3-taraxerone in the leaf extract. Two anthraquinones (emodin and physcion were isolated and identified from the root extract. Phytochemical screening using the pharmacognostic methods revealed the presence of flavonoids and tannins in the leaves and roots. Anthraquinones were only found in the root extract, no alkaloids, coumarins, saponins and simple phenolics were present. The antifungal activity of C. mollis extracts and anthraquinones isolated from the root of this plant against Botryospheria ribis, B. rhodina, Lasiodiplodia theobromae and Fusarium sp showed promising results for their use as fungicides, where emodin was the most active compound, which inhibited the microorganisms tested up to 44%.

  4. Rhodamine B induces long nucleoplasmic bridges and other nuclear anomalies in Allium cepa root tip cells.

    Science.gov (United States)

    Tan, Dehong; Bai, Bing; Jiang, Donghua; Shi, Lin; Cheng, Shunchang; Tao, Dongbing; Ji, Shujuan

    2014-03-01

    The cytogenetic toxicity of rhodamine B on root tip cells of Allium cepa was investigated. A. cepa were cultured in water (negative control), 10 ppm methyl methanesulfonate (positive control), and three concentrations of rhodamine B (200, 100, and 50 ppm) for 7 days. Rhodamine B inhibited mitotic activity; increased nuclear anomalies, including micronuclei, nuclear buds, and bridged nuclei; and induced oxidative stress in A. cepa root tissues. Furthermore, a substantial amount of long nucleoplasmic bridges were entangled together, and some nuclei were simultaneously linked to several other nuclei and to nuclear buds with nucleoplasmic bridges in rhodamine B-treated cells. In conclusion, rhodamine B induced cytogenetic effects in A. cepa root tip cells, which suggests that the A. cepa root is an ideal model system for detecting cellular interactions.

  5. Saiboku-to, a Kampo herbal medicine, inhibits LTC4 release from eosinophils

    Directory of Open Access Journals (Sweden)

    Koichi Hirai

    1998-01-01

    Full Text Available Saiboku-to (TJ-96, a traditional Kampo herbal formation, has been used in the treatment of bronchial asthma in Japan as an anti-allergy herbal medicine. We investigated the effect of TJ-96 on leukotriene (LTC4 release from eosinophils and basophils isolated from healthy volunteers. Pre-incubation of eosinophils with TJ-96 inhibited ionophore- or formyl-methionyl-leucyl-phenylalanine (FMLP-induced LTC4 generation by eosinophils in a dose-dependent fashion. The TJ-96 was more potent in the release by ionophore (IC50 = 60 mg/mL than the release induced by FMLP (IC50 = 300 mg/mL. Maximal inhibition was observed when eosinophils were pretreated with TJ-96 for 5 min. Although TJ-96 at high concentrations inhibited IgE-mediated histamine release from human basophils, inhibition of IgE-mediated LTC4 release was not statistically significant. The potent inhibitory activity was found in the extract of Glycyrrhiza root, one of the herbal components of TJ-96, but the inhibitory effects were not due to either glycyrrhizin or liquiritin, the main elements of the Glycyrrhiza root. These results raise the possibility that the clinical efficacy of TJ-96 is derived, at least in part, from its potent inhibitory effect on LTC4 release from eosinophils.

  6. Acetylcholinesterase inhibition and antibacterial activity of Mondia whitei adventitious roots and ex vitro-grown somatic embryogenic-biomass

    Directory of Open Access Journals (Sweden)

    Ponnusamy Baskaran

    2016-10-01

    Full Text Available Mondia whitei (Hook.f. Skeels is an important endangered medicinal and commercial plant in South Africa. In vitro propagation systems are required for biomass production and bioactivity analysis to supplement wild resources/stocks. Adventitious roots from somatic embryogenic explants using suspension culture and ex vitro-grown plants produced via somatic embryogenesis were established using different plant growth regulator treatments. The adventitious root biomass and different parts of ex vitro-grown and mother plants were used to investigate the potential for acetylcholinesterase (AChE and antibacterial activities. Adventitious roots derived from 2.5 µM indole-3-acetic acid (IAA treatments and ex vitro-grown plants derived from meta-topolin riboside (mTR and IAA treatments gave the best AChE and antibacterial activities. The in vitro-established M. whitei and ex vitro biomass have comparable ability to function as inhibitors of acetylcholinesterase and antibacterial agents, and can be used as potent bioresources in traditional medicine

  7. Descendant root volume varies as a function of root type: estimation of root biomass lost during uprooting in Pinus pinaster.

    Science.gov (United States)

    Danjon, Frédéric; Caplan, Joshua S; Fortin, Mathieu; Meredieu, Céline

    2013-01-01

    Root systems of woody plants generally display a strong relationship between the cross-sectional area or cross-sectional diameter (CSD) of a root and the dry weight of biomass (DWd) or root volume (Vd) that has grown (i.e., is descendent) from a point. Specification of this relationship allows one to quantify root architectural patterns and estimate the amount of material lost when root systems are extracted from the soil. However, specifications of this relationship generally do not account for the fact that root systems are comprised of multiple types of roots. We assessed whether the relationship between CSD and Vd varies as a function of root type. Additionally, we sought to identify a more accurate and time-efficient method for estimating missing root volume than is currently available. We used a database that described the 3D root architecture of Pinus pinaster root systems (5, 12, or 19 years) from a stand in southwest France. We determined the relationship between CSD and Vd for 10,000 root segments from intact root branches. Models were specified that did and did not account for root type. The relationships were then applied to the diameters of 11,000 broken root ends to estimate the volume of missing roots. CSD was nearly linearly related to the square root of Vd, but the slope of the curve varied greatly as a function of root type. Sinkers and deep roots tapered rapidly, as they were limited by available soil depth. Distal shallow roots tapered gradually, as they were less limited spatially. We estimated that younger trees lost an average of 17% of root volume when excavated, while older trees lost 4%. Missing volumes were smallest in the central parts of root systems and largest in distal shallow roots. The slopes of the curves for each root type are synthetic parameters that account for differentiation due to genetics, soil properties, or mechanical stimuli. Accounting for this differentiation is critical to estimating root loss accurately.

  8. Effect of the association between citric acid and EDTA on root surface etching.

    Science.gov (United States)

    Manzolli Leite, Fabio Renato; Nascimento, Gustavo Giacomelli; Manzolli Leite, Elza Regina; Leite, Amauri Antiquera; Cezar Sampaio, Josá Eduardo

    2013-09-01

    This study aims to compare the clot stabilization on root surfaces conditioned with citric acid and ethylenediamine-tetraacetic acid (EDTA). Scaled root samples (n = 100) were set in fve groups: group I-control group (saline solution); group II (24% EDTA); group III (25% citric acid); group IV (EDTA + citric acid); group V (citric acid + EDTA). Fifty samples were assessed using the root surface modifcation index (RSMI). The other 50 received a blood drop after conditioning. Clot formation was assessed using blood elements adhesion index (BEAI). A blind examiner evaluated photomicrographs. Statistical analysis considered p EDTA employment before citric acid (group-IV) reduced clot formation in comparison to citric acid use alone (group-III). Root conditioning with citric acid alone and before EDTA had the best results for smear layer removal and clot stabilization. EDTA inhibited clot stabilization on root surface and must have a residual activity once it has diminished clot adhesion to root even after citric acid conditioning. Thus, EDTA can be used to neutralize citric acid effects on periodontal cells without affecting clot stabilization. Clinical signifcance: To demonstrate that citric acid use on root surfaces previously affected by periodontal disease may favor clot stabilization and may have a benefcial effect on surgical outcomes. Also, EDTA can be used to neutralize citric acid effects on periodontal cells.

  9. Competitive sorption of heavy metals by water hyacinth roots.

    Science.gov (United States)

    Zheng, Jia-Chuan; Liu, Hou-Qi; Feng, Hui-Min; Li, Wen-Wei; Lam, Michael Hon-Wah; Lam, Paul Kwan-Sing; Yu, Han-Qing

    2016-12-01

    Heavy metal pollution is a global issue severely constraining aquaculture practices, not only deteriorating the aquatic environment but also threatening the aquaculture production. One promising solution is adopting aquaponics systems where a synergy can be established between aquaculture and aquatic plants for metal sorption, but the interactions of multiple metals in such aquatic plants are poorly understood. In this study, we investigated the absorption behaviors of Cu(II) and Cd(II) in water by water hyacinth roots in both single- and binary-metal systems. Cu(II) and Cd(II) were individually removed by water hyacinth roots at high efficiency, accompanied with release of protons and cations such as Ca 2+ and Mg 2+ . However, in a binary-metal arrangement, the Cd(II) sorption was significantly inhibited by Cu(II), and the higher sorption affinity of Cu(II) accounted for its competitive sorption advantage. Ionic exchange was identified as a predominant mechanism of the metal sorption by water hyacinth roots, and the amine and oxygen-containing groups are the main binding sites accounting for metal sorption via chelation or coordination. This study highlights the interactive impacts of different metals during their sorption by water hyacinth roots and elucidates the underlying mechanism of metal competitive sorption, which may provide useful implications for optimization of phytoremediation system and development of more sustainable aquaculture industry. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Rhizosphere microbial community structure in relation to root location and plant iron nutritional status.

    Science.gov (United States)

    Yang, C H; Crowley, D E

    2000-01-01

    Root exudate composition and quantity vary in relation to plant nutritional status, but the impact of the differences on rhizosphere microbial communities is not known. To examine this question, we performed an experiment with barley (Hordeum vulgare) plants under iron-limiting and iron-sufficient growth conditions. Plants were grown in an iron-limiting soil in root box microcosms. One-half of the plants were treated with foliar iron every day to inhibit phytosiderophore production and to alter root exudate composition. After 30 days, the bacterial communities associated with different root zones, including the primary root tips, nonelongating secondary root tips, sites of lateral root emergence, and older roots distal from the tip, were characterized by using 16S ribosomal DNA (rDNA) fingerprints generated by PCR-denaturing gradient gel electrophoresis (DGGE). Our results showed that the microbial communities associated with the different root locations produced many common 16S rDNA bands but that the communities could be distinguished by using correspondence analysis. Approximately 40% of the variation between communities could be attributed to plant iron nutritional status. A sequence analysis of clones generated from a single 16S rDNA band obtained at all of the root locations revealed that there were taxonomically different species in the same band, suggesting that the resolving power of DGGE for characterization of community structure at the species level is limited. Our results suggest that the bacterial communities in the rhizosphere are substantially different in different root zones and that a rhizosphere community may be altered by changes in root exudate composition caused by changes in plant iron nutritional status.

  11. Antimalarial and cytotoxic activities of roots and fruits fractions of Astrodaucus persicus extract

    Directory of Open Access Journals (Sweden)

    Saied Goodarzi

    2017-12-01

    Full Text Available Objective(s:Astrodaucus persicus (Apiaceae is one of the two species of this genus which grows in different parts of Iran. Roots of this plant were rich in benzodioxoles and used as food additive or salad in Iran and near countries. The aim of present study was evaluation of antimalarial and cytotoxic effects of different fractions of A. persicus fruits and roots extracts. Materials and Methods: Ripe fruits and roots of A. persicuswere extracted and fractionated by hexane, chloroform, ethyl acetate and methanol, separately. Antimalarial activities of fractions were performed based on Plasmodium berghei suppressive test in mice model and percentage of parasitemia and suppression were determined for each sample. Cytotoxicity of fruits and roots fractions were investigated against human breast adenocarcinoma (MCF-7, colorectal carcinoma (SW480 and normal (L929 cell lines by MTT assay and IC50 of them were measured. Results: Hexane fraction of roots extract (RHE and ethyl acetate fraction of fruits extract (FEA of A. persicus demonstrated highest parasite inhibition (73.3 and 72.3%, respectively at 500 mg/kg/day which were significantly different from negative control group (P

  12. Root anatomy, morphology, and longevity among root orders in Vaccinium corymbosum (Ericaceae).

    Science.gov (United States)

    Valenzuela-Estrada, Luis R; Vera-Caraballo, Vivianette; Ruth, Leah E; Eissenstat, David M

    2008-12-01

    Understanding root processes at the whole-plant or ecosystem scales requires an accounting of the range of functions within a root system. Studying root traits based on their branching order can be a powerful approach to understanding this complex system. The current study examined the highly branched root system of the ericoid plant, Vaccinium corymbosum L. (highbush blueberry) by classifying its root orders with a modified version of the morphometric approach similar to that used in hydrology for stream classification. Root anatomy provided valuable insight into variation in root function across orders. The more permanent portion of the root system occurred in 4th- and higher-order roots. Roots in these orders had radial growth; the lowest specific root length, N:C ratios, and mycorrhizal colonization; the highest tissue density and vessel number; and the coarsest root diameter. The ephemeral portion of the root system was mainly in the first three root orders. First- and 2nd-order roots were nearly anatomically identical, with similar mycorrhizal colonization and diameter, and also, despite being extremely fine, median lifespans were not very short (115-120 d; estimated with minirhizotrons). Our research underscores the value of examining root traits by root order and its implications to understanding belowground processes.

  13. Gibberellins and gravitropism in maize shoots: endogenous gibberellin-like substances and movement and metabolism of [3H]Gibberellin A20

    Science.gov (United States)

    Rood, S. B.; Kaufman, P. B.; Abe, H.; Pharis, R. P.

    1987-01-01

    from these lower leaf sheath pulvini by capillary gas chromatography-selected ion monitoring. Results from all of these experiments are consistent with a role for GAs in the differential shoot growth that follows gravitropism, although the results do not eliminate the possibility that the redistribution of GAs results from the gravitropic response.

  14. α-Dendrotoxin inhibits the ASIC current in dorsal root ganglion neurons from rat.

    Science.gov (United States)

    Báez, Adriana; Salceda, Emilio; Fló, Martín; Graña, Martín; Fernández, Cecilia; Vega, Rosario; Soto, Enrique

    2015-10-08

    Dendrotoxins are a group of peptide toxins purified from the venom of several mamba snakes. α-Dendrotoxin (α-DTx, from the Eastern green mamba Dendroaspis angusticeps) is a well-known blocker of voltage-gated K(+) channels and specifically of K(v)1.1, K(v)1.2 and K(v)1.6. In this work we show that α-DTx inhibited the ASIC currents in DRG neurons (IC50=0.8 μM) when continuously perfused during 25 s (including a 5 s pulse to pH 6.1), but not when co-applied with the pH drop. Additionally, we show that α-DTx abolished a transient component of the outward current that, in some experiments, appeared immediately after the end of the acid pulse. Our data indicate that α-DTx inhibits ASICs in the high nM range while some Kv are inhibited in the low nM range. The α-DTx selectivity and its potential interaction with ASICs should be taken in consideration when DTx is used in the high nM range. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. Oxidative defence reactions in sunflower roots induced by methyl-jasmonate and methyl-salicylate and their relation with calcium signalling.

    Science.gov (United States)

    Garrido, Inmaculada; Espinosa, Francisco; Alvarez-Tinaut, M Carmen

    2009-10-01

    Ca(2+) plays a critical role as second messenger in the signal-response coupling of plant defence responses, and methyl-jasmonate and methyl-salicylate are important components of signal transduction cascades activating plant defences. When intact axenic non-induced seedling roots of sunflower were treated with different Ca(2+) concentrations up to 1 mM, there was no significant increase in O(2)(*-) generation or DMAB-MBTH peroxidase (extracellular, ECPOX) activities in the apoplast, probably because these roots had enough Ca(2+) in their exo- and endocellular reservoirs. Both activities were strongly inhibited by the RBOH-NADPH oxidase inhibitor DPI and by the Ca(2+) surrogate antagonist La(3+), but the voltage-dependent Ca(2+) channel blocker verapamil was only inhibitory at concentrations higher than those active on animal L-type Ca(2+) channels. Concentrations >5 mM EGTA (chelating Ca(2+) in the apoplast) and Li(+) (inhibiting PI cycle dependent endogenous Ca(2+) fluxes) also inhibited both activities. W7, inhibitor of binding of Ca-CaM to its target protein, enhanced both activities, but the inactive analogue W5 showed a similar effect. Our data suggest that Ca(2+) from exocellular and, to a lesser extent, from endocellular stores is involved in oxidative activities, and that RBOH-NADPH oxidase is the main system supporting them. Ca(2+) activation of the PM cytosolic side of RBOH-NADPH oxidase is probably the key to Ca(2+) involvement in these processes. Roots induced by MeJA or MeSA showed significant enhancement of both oxidative activities, as corresponding to the oxidative burst evoked by the two phytohormones in the root apoplast. But while ECPOX activity showed a response to the effectors similar to that described above for non-induced roots, O(2)(*-) generation activity in the apoplast of induced roots was insensitive to EGTA, verapamil and Li(+), the inhibitors of exogenous and endogenous Ca(2+) fluxes; only DPI and La(3+) were inhibitory. As

  16. A Co-Opted Hormonal Cascade Activates Dormant Adventitious Root Primordia upon Flooding in Solanum dulcamara.

    Science.gov (United States)

    Dawood, Thikra; Yang, Xinping; Visser, Eric J W; Te Beek, Tim A H; Kensche, Philip R; Cristescu, Simona M; Lee, Sangseok; Floková, Kristýna; Nguyen, Duy; Mariani, Celestina; Rieu, Ivo

    2016-04-01

    Soil flooding is a common stress factor affecting plants. To sustain root function in the hypoxic environment, flooding-tolerant plants may form new, aerenchymatous adventitious roots (ARs), originating from preformed, dormant primordia on the stem. We investigated the signaling pathway behind AR primordium reactivation in the dicot species Solanum dulcamara Transcriptome analysis indicated that flooding imposes a state of quiescence on the stem tissue, while increasing cellular activity in the AR primordia. Flooding led to ethylene accumulation in the lower stem region and subsequently to a drop in abscisic acid (ABA) level in both stem and AR primordia tissue. Whereas ABA treatment prevented activation of AR primordia by flooding, inhibition of ABA synthesis was sufficient to activate them in absence of flooding. Together, this reveals that there is a highly tissue-specific response to reduced ABA levels. The central role for ABA in the response differentiates the pathway identified here from the AR emergence pathway known from rice (Oryza sativa). Flooding and ethylene treatment also induced expression of the polar auxin transporter PIN2, and silencing of this gene or chemical inhibition of auxin transport inhibited primordium activation, even though ABA levels were reduced. Auxin treatment, however, was not sufficient for AR emergence, indicating that the auxin pathway acts in parallel with the requirement for ABA reduction. In conclusion, adaptation of S. dulcamara to wet habitats involved co-option of a hormonal signaling cascade well known to regulate shoot growth responses, to direct a root developmental program upon soil flooding. © 2016 American Society of Plant Biologists. All Rights Reserved.

  17. Ammonium assimilation in rice based on the occurrence of 15N and inhibition of glutamine synthetase activity

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, J. R.; Huber, D. M.; Lee, T. C.; Tsai, C. Y.

    1995-07-01

    Assimilation of ammonium (NH4) into free amino acids and total reduced nitrogen (N) was monitored in both roots and shoots of two-week old rice seedlings supplied with 5 mM 99% (15NH4)2SO4 in aerated hydroponic culture with or without a 2 h preincubation with 1 mM methionine sulfoximine (MSX) an inhibitor of glutamine synthetase (GS) activity. 15NH4 was not assimilated into amino acids when the GS/GOGAT (glutamate synthase) cycle was inhibited by MSX. Inhibition of glutamine synthetase (GS) activity in roots with MSX increased both the amount of NH4 and the abundance of 15N labeled NH4. In contrast, the amount of Gln and Glu, and their proportions as 15N, decreased in roots when GS activity was inhibited. This research confirms the importance of GS/GOGAT in NH4 assimilation in rice roots. 15N-labeled studies indicate that NH4 ions incorporated by roots of rice are transformed primarily into glutamine (Gin) and glutamic acid (Glu) before being converted to other amino acids through transamination. The formation of amino acids such as aspartic acid (Asp) and alanine (Ala) directly from free NH4 in roots also has been reported. Translocation of free NH4 to plant shoots, based on the concentration of free NH4 in xylem exudate, has been reported in tomato, although NH4 in shoots primarily originates from nitrate reduction in the shoot. Photorespiration also can contribute to the accumulation of NH4 in leaves. The GS/GOGAT cycle appears to be primarily responsible for the assimilation of exogenously supplied NH4 and NH4 derived from nitrate reduction in leaves, as well as NH4 derived from photorespiration. Genetic evidence cited to support this conclusion includes the lethal effect of photorespiratory conditions on plant mutants deficient in chloroplast-localized GS and GOGAT activities, and the rapid accumulation of free NH4 in GS-deficient mutants under photorespiratory conditions. The present study was initiated to quantify the in vivo amino acid synthesis in rice

  18. Ammonium assimilation in rice based on the occurrence of 15N and inhibition of glutamine synthetase activity

    International Nuclear Information System (INIS)

    Magalhaes, J.R.; Huber, D.M.; Lee, T.C.; Tsai, C.Y.

    1995-01-01

    Assimilation of ammonium (NH4) into free amino acids and total reduced nitrogen (N) was monitored in both roots and shoots of two-week old rice seedlings supplied with 5 mM 99% (15NH4)2SO4 in aerated hydroponic culture with or without a 2 h preincubation with 1 mM methionine sulfoximine (MSX) an inhibitor of glutamine synthetase (GS) activity. 15NH4 was not assimilated into amino acids when the GS/GOGAT (glutamate synthase) cycle was inhibited by MSX. Inhibition of glutamine synthetase (GS) activity in roots with MSX increased both the amount of NH4 and the abundance of 15N labeled NH4. In contrast, the amount of Gln and Glu, and their proportions as 15N, decreased in roots when GS activity was inhibited. This research confirms the importance of GS/GOGAT in NH4 assimilation in rice roots. 15N-labeled studies indicate that NH4 ions incorporated by roots of rice are transformed primarily into glutamine (Gin) and glutamic acid (Glu) before being converted to other amino acids through transamination. The formation of amino acids such as aspartic acid (Asp) and alanine (Ala) directly from free NH4 in roots also has been reported. Translocation of free NH4 to plant shoots, based on the concentration of free NH4 in xylem exudate, has been reported in tomato, although NH4 in shoots primarily originates from nitrate reduction in the shoot. Photorespiration also can contribute to the accumulation of NH4 in leaves. The GS/GOGAT cycle appears to be primarily responsible for the assimilation of exogenously supplied NH4 and NH4 derived from nitrate reduction in leaves, as well as NH4 derived from photorespiration. Genetic evidence cited to support this conclusion includes the lethal effect of photorespiratory conditions on plant mutants deficient in chloroplast-localized GS and GOGAT activities, and the rapid accumulation of free NH4 in GS-deficient mutants under photorespiratory conditions. The present study was initiated to quantify the in vivo amino acid synthesis in rice

  19. Reactive Oxygen Species Generated by NADPH Oxidases Promote Radicle Protrusion and Root Elongation during Rice Seed Germination

    Directory of Open Access Journals (Sweden)

    Wen-Yan Li

    2017-01-01

    Full Text Available Seed germination is a complicated biological process that requires regulation through various enzymatic and non-enzymatic mechanisms. Although it has been recognized that reactive oxygen species (ROS regulate radicle emergence and root elongation in a non-enzymatic manner during dicot seed germination, the role of ROS in monocot seed germination remains unknown. NADPH oxidases (NOXs are the major ROS producers in plants; however, whether and how NOXs regulate rice seed germination through ROS generation remains unclear. Here, we report that diphenyleneiodinium (DPI, a specific NOX inhibitor, potently inhibited embryo and seedling growth—especially that of the radicle and of root elongation—in a dose-dependent manner. Notably, the DPI-mediated inhibition of radicle and root growth could be eliminated by transferring seedlings from DPI to water. Furthermore, ROS production/accumulation during rice seed germination was quantified via histochemistry. Superoxide radicals (O2−, hydrogen peroxide (H2O2 and hydroxyl radicals (•OH accumulated steadily in the coleorhiza, radicle and seedling root of germinating rice seeds. Expression profiles of the nine typical NOX genes were also investigated. According to quantitative PCR, OsNOX5, 7 and 9 were expressed relatively higher. When seeds were incubated in water, OsNOX5 expression progressively increased in the embryo from 12 to 48 h, whereas OsNOX7 and 9 expressions increased from 12 to 24 h and decreased thereafter. As expected, DPI inhibits the expression at predetermined time points for each of these genes. Taken together, these results suggest that ROS produced by NOXs are involved in radicle and root elongation during rice seed germination, and OsNOX5, 7 and 9 could play crucial roles in rice seed germination. These findings will facilitate further studies of the roles of ROS generated by NOXs during seed germination and seedling establishment and also provide valuable information for the

  20. OpenSimRoot: widening the scope and application of root architectural models.

    Science.gov (United States)

    Postma, Johannes A; Kuppe, Christian; Owen, Markus R; Mellor, Nathan; Griffiths, Marcus; Bennett, Malcolm J; Lynch, Jonathan P; Watt, Michelle

    2017-08-01

    OpenSimRoot is an open-source, functional-structural plant model and mathematical description of root growth and function. We describe OpenSimRoot and its functionality to broaden the benefits of root modeling to the plant science community. OpenSimRoot is an extended version of SimRoot, established to simulate root system architecture, nutrient acquisition and plant growth. OpenSimRoot has a plugin, modular infrastructure, coupling single plant and crop stands to soil nutrient and water transport models. It estimates the value of root traits for water and nutrient acquisition in environments and plant species. The flexible OpenSimRoot design allows upscaling from root anatomy to plant community to estimate the following: resource costs of developmental and anatomical traits; trait synergisms; and (interspecies) root competition. OpenSimRoot can model three-dimensional images from magnetic resonance imaging (MRI) and X-ray computed tomography (CT) of roots in soil. New modules include: soil water-dependent water uptake and xylem flow; tiller formation; evapotranspiration; simultaneous simulation of mobile solutes; mesh refinement; and root growth plasticity. OpenSimRoot integrates plant phenotypic data with environmental metadata to support experimental designs and to gain a mechanistic understanding at system scales. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  1. Light as stress factor to plant roots - case of root halotropism.

    Science.gov (United States)

    Yokawa, Ken; Fasano, Rossella; Kagenishi, Tomoko; Baluška, František

    2014-01-01

    Despite growing underground, largely in darkness, roots emerge to be very sensitive to light. Recently, several important papers have been published which reveal that plant roots not only express all known light receptors but also that their growth, physiology and adaptive stress responses are light-sensitive. In Arabidopsis, illumination of roots speeds-up root growth via reactive oxygen species-mediated and F-actin dependent process. On the other hand, keeping Arabidopsis roots in darkness alters F-actin distribution, polar localization of PIN proteins as well as polar transport of auxin. Several signaling components activated by phytohormones are overlapping with light-related signaling cascade. We demonstrated that the sensitivity of roots to salinity is altered in the light-grown Arabidopsis roots. Particularly, light-exposed roots are less effective in their salt-avoidance behavior known as root halotropism. Here we discuss these new aspects of light-mediated root behavior from cellular, physiological and evolutionary perspectives.

  2. Tobacco Rotated with Rapeseed for Soil-Borne Phytophthora Pathogen Biocontrol: Mediated by Rapeseed Root Exudates

    Directory of Open Access Journals (Sweden)

    Yuting Fang

    2016-06-01

    Full Text Available Black shank, caused by Phytophthora parasitica var. nicotianae, is a widespread and destructive disease of tobacco. Crop rotation is essential in controlling black shank. Here, we confirmed that rotating black shank-infested fields with rapeseed (Brassica napus suppressed the incidence this disease. Further study demonstrated that rapeseed roots have a strong ability to attract zoospores and subsequently stop the swimming of zoospores into cystospores. Then, rapeseed roots secrete a series of antimicrobial compounds, including 2-butenoic acid, benzothiazole, 2-(methylthiobenzothiazole, 1-(4-ethylphenyl-ethanone, and 4-methoxyindole, to inhibit the cystospore germination and mycelial growth of P. parasitica var. nicotianae. Thus, rapeseed rotated with tobacco suppresses tobacco black shank disease through the chemical weapons secreted by rapeseed roots.

  3. effects of different concentrations of auxins on rooting and root

    African Journals Online (AJOL)

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    ABSTRACT: The effect of auxins and their different concentrations on rooting and root ... primary root length and the longest primary root was recorded with the ... ceuticals, lubricants, foods, electrical insulators, .... stem cuttings of jojoba treated with IBA and NAA, .... increasing cell division and enlargement at each.

  4. Preparation of wheat root plasma membrane vesicles and effect of water stress on 45Ca2+ transport activity

    International Nuclear Information System (INIS)

    Lu Jinyin; Gao Junfeng; Cao Cuiling

    1998-01-01

    The wheat roots plasma membrane (PM) vesicles were obtained by sucrose gradient centrifugation. The experiment results shows that the wheat roots of Zhengyin No.1 PM H + -ATPase latent activity was 24%, and PM inside-out vesicle (IOV) accounts for 76%. With -1.0 MPa stress of 24h, PM Ca 2+ -ATPase activity of both orientation wheat roots were increased. Under normal water condition and PEG stress, 62% and 53% of the enzyme activity was inhibited respectively by EGTA, radioactive calcium-45 transport amount was 22.09 nmol/mg pro and 4.17 nmol/mg pro. respectively with PM-IOV.PEG stress results in a decrease of 45 Ca 2+ transport amount of wheat roots PM-IOV by 81%

  5. Assessment of Euphorbia hirta L. Leaf, Flower, Stem and Root Extracts for Their Antibacterial and Antifungal Activity and Brine Shrimp Lethality

    Directory of Open Access Journals (Sweden)

    Santhanam Amutha

    2010-08-01

    Full Text Available The antimicrobial activities of the methanolic extracts of Euphorbia hirta L leaves, flowers, stems and roots were evaluated against some medically important bacteria and yeast using the agar disc diffusion method. Four Gram positive (Staphylococcus aureus, Micrococcus sp., Bacillus subtilis and Bacillus thuringensis, four Gram negative (Escherichia coli, Klebsiella pneumonia, Salmonella typhi and P. mirabilis and one yeast (Candida albicans species were screened. Inhibition zones ranged between 16–29 mm. Leaves extract inhibited the growth of all tested microorganisms with large zones of inhibition, followed by that of flowers, which also inhibited all the bacteria except C. albicans. The most susceptible microbes to all extracts were S. aureus and Micrococcus sp. Root extract displayed larger inhibition zones against Gram positive bacteria than Gram negative bacteria and had larger inhibition zones compared to stem extract. The lowest MIC values were obtained with E. coli and C. albicans (3.12 mg/mL, followed by S. aureus (12.50 mg/mL and P. mirabilis (50.00 mg/mL. All the other bacteria had MIC values of 100.00 mg/mL. Scanning Electron Microscopic (SEM studies revealed that the cells exposed to leaf extract displayed a rough surface with multiple blends and invaginations which increased with increasing time of treatment, and cells exposed to leaf extract for 36 h showed the most damage, with abundant surface cracks which may be related to final cell collapse and lossThe antimicrobial activities of the methanolic extracts of Euphorbia hirta L leaves, flowers, stems and roots were evaluated against some medically important bacteria and yeast using the agar disc diffusion method. Four Gram positive (Staphylococcus aureus, Micrococcus sp., Bacillus subtilis and Bacillus thuringensis, four Gram negative (Escherichia coli, Klebsiella pneumonia, Salmonella typhi and P. mirabilis and one yeast (Candida albicans species were screened. Inhibition

  6. Seedling root targets

    Science.gov (United States)

    Diane L. Haase

    2011-01-01

    Roots are critical to seedling performance after outplanting. Although root quality is not as quick and simple to measure as shoot quality, target root characteristics should be included in any seedling quality assessment program. This paper provides a brief review of root characteristics most commonly targeted for operational seedling production. These are: root mass...

  7. Effect of Root Moisture Content and Diameter on Root Tensile Properties

    Science.gov (United States)

    Yang, Yuanjun; Chen, Lihua; Li, Ning; Zhang, Qiufen

    2016-01-01

    The stabilization of slopes by vegetation has been a topical issue for many years. Root mechanical characteristics significantly influence soil reinforcement; therefore it is necessary to research into the indicators of root tensile properties. In this study, we explored the influence of root moisture content on tensile resistance and strength with different root diameters and for different tree species. Betula platyphylla, Quercus mongolica, Pinus tabulaeformis, and Larix gmelinii, the most popular tree species used for slope stabilization in the rocky mountainous areas of northern China, were used in this study. A tensile test was conducted after root samples were grouped by diameter and moisture content. The results showedthat:1) root moisture content had a significant influence on tensile properties; 2) slightly loss of root moisture content could enhance tensile strength, but too much loss of water resulted in weaker capacity for root elongation, and consequently reduced tensile strength; 3) root diameter had a strong positive correlation with tensile resistance; and4) the roots of Betula platyphylla had the best tensile properties when both diameter and moisture content being controlled. These findings improve our understanding of root tensile properties with root size and moisture, and could be useful for slope stabilization using vegetation. PMID:27003872

  8. Root - shoot - signaling in Chenopodium rubrum L. as studied by 15O labeled water uptake

    International Nuclear Information System (INIS)

    Ohya, T.; Hayashi, Y.; Tanoi, K.; Rai, H.; Nakanishi, T.M.; Suzuki, K.; Albrechtova, J.T.P.; Wagner, E.

    2005-01-01

    Full text: It has been demonstrated with C. rubrum that the different organ systems are transmitting surface action potentials which might be the basis for systemic signal transduction. Shoot tip respectively root generated action potentials travel along the stem axis. Shoot tip generated action potentials arriving at the basis can be reflected and travel upwards. The radioactive labeling technique was established at the NIRS in Inage, Japan. About 2 GBq of 15 O labeled Hoagland's solution was supplied to the plant root or cut stem in a phytotron at 25 o C with 45 % of relative humidity and continuous light. By cutting the shoot apical bud and the apices of main side branches the uptake of 15 O labeled water was inhibited in plants with intact roots but not in plants with roots cut. Because of the short half-life of 15 O (2 min), experiments could be repeated in hourly intervals. Cutting the apex probably limits root water uptake via a hydraulic-electrochemical signal. The results are discussed with respect to the significance of a continuous communication between the root system and the shoot apical meristem(s) in the adaptation of plants to their environment. (author)

  9. External hyphae of Rhizophagus irregularis DAOM 197198 are less sensitive to low pH than roots in arbuscular mycorrhizae: evidence from axenic culture system.

    Science.gov (United States)

    Wang, Ning; Feng, Zengwei; Zhou, Yang; Zhu, Honghui; Yao, Qing

    2017-10-01

    The growth of plant roots and arbuscular mycorrhizal fungi (AMF) can be inhibited by low pH; however, it is largely unknown which is more sensitive to low pH. This study aimed to compare the physiological and molecular responses of external hyphae (EH) and roots to low pH in terms of growth, development and functioning. We established AM symbiosis in a two-compartmented system (root compartment, RC; hyphal compartment, HC) using AMF and transformed hairy roots and exposed them to pH 6.5 and/or pH 4.5. The results showed that pH 4.5 significantly decreased root cell viability, while EH at pH 6.5 attenuated the effect. In either RC or HC, pH 4.5 reduced biomass, P content, colonization, ALP activity in roots, and ALP activity and polyphosphate accumulation in EH. GintPT expression in EH was inhibited by pH 4.5 in HC but not in RC. The expression of mycorrhiza-responsive LePTs was significantly reduced by the lower colonization due to decreased pH in either RC or HC, while the expression of non-mycorrhiza-responsive LePTs was not affected. Variation partitioning analysis indicated that EH was less sensitive to low pH than roots. The interactions between roots and EH under low pH stress merit further investigation. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  10. Root canal treatment of bilateral three-rooted maxillary first premolars

    Directory of Open Access Journals (Sweden)

    Bhavana Gandhi

    2012-01-01

    Full Text Available In endodontics, several anatomic variations occur in teeth, both externally and in the internal root morphology, which play a very significant role in the diagnosis and treatment outcome. A thorough knowledge of the root canal anatomy, careful interpretation of the angled radiographs, proper endodontic access cavity preparation, and exploration of the root canal are the prerequisites for endodontic success. In a maxillary first premolar, it is rare to find extra roots and canals, and the aim of the present article is to report a case about the successful diagnosis and clinical management of bilateral three-rooted maxillary first premolars, with three independent root canals.

  11. Effects of irradiation with low-energy nitrogen ion injection on root tip cells of broad bean

    International Nuclear Information System (INIS)

    Huang Yaqin; Li Jinzhe; Huang Qunce

    2012-01-01

    In order to study the cytogenetic effects of low-energy nitrogen ion irradiation, broad bean seed embryo was irradiated by different doses of nitrogen ions. Micronucleus rate, mitotic index and chromosome aberration in root-tip cells were analyzed. The results showed that the injection of ions inhibited mitosis of root tip cells, interfered the normal process of mitosis, caused aberrations of chromosome structure, behavior and number. The frequency of micronucleus and chromosomal aberrations increased with the increasing radiation dosage, while mitotic index decreased. (authors)

  12. Brassinolide Increases Potato Root Growth In Vitro in a Dose-Dependent Way and Alleviates Salinity Stress

    Directory of Open Access Journals (Sweden)

    Yueqing Hu

    2016-01-01

    Full Text Available Brassinosteroids (BRs are steroidal phytohormones that regulate various physiological processes, such as root development and stress tolerance. In the present study, we showed that brassinolide (BL affects potato root in vitro growth in a dose-dependent manner. Low BL concentrations (0.1 and 0.01 μg/L promoted root elongation and lateral root development, whereas high BL concentrations (1–100 μg/L inhibited root elongation. There was a significant (P<0.05 positive correlation between root activity and BL concentrations within a range from 0.01 to 100 μg/L, with the peak activity of 8.238 mg TTC·g−1 FW·h−1 at a BL concentration of 100 μg/L. Furthermore, plants treated with 50 μg/L BL showed enhanced salt stress tolerance through in vitro growth. Under this scenario, BL treatment enhanced the proline content and antioxidant enzymes’ (superoxide dismutase, peroxidase, and catalase activity and reduced malondialdehyde content in potato shoots. Application of BL maintain K+ and Na+ homeostasis by improving tissue K+/Na+ ratio. Therefore, we suggested that the effects of BL on root development from stem fragments explants as well as on primary root development are dose-dependent and that BL application alleviates salt stress on potato by improving root activity, root/shoot ratio, and antioxidative capacity in shoots and maintaining K+/Na+ homeostasis in potato shoots and roots.

  13. Effect of nitrate supply and mycorrhizal inoculation on characteristics of tobacco root plasma membrane vesicles.

    Science.gov (United States)

    Moche, Martin; Stremlau, Stefanie; Hecht, Lars; Göbel, Cornelia; Feussner, Ivo; Stöhr, Christine

    2010-01-01

    Plant plasma membrane (pm) vesicles from mycorrhizal tobacco (Nicotiana tabacum cv. Samsun) roots were isolated with negligible fungal contamination by the aqueous two-phase partitioning technique as proven by fatty acid analysis. Palmitvaccenic acid became apparent as an appropriate indicator for fungal membranes in root pm preparations. The pm vesicles had a low specific activity of the vanadate-sensitive ATPase and probably originated from non-infected root cells. In a phosphate-limited tobacco culture system, root colonisation by the vesicular arbuscular mycorrhizal fungus, Glomus mosseae, is inhibited by external nitrate in a dose-dependent way. However, detrimental high concentrations of 25 mM nitrate lead to the highest colonisation rate observed, indicating that the defence system of the plant is impaired. Nitric oxide formation by the pm-bound nitrite:NO reductase increased in parallel with external nitrate supply in mycorrhizal roots in comparison to the control plants, but decreased under excess nitrate. Mycorrhizal pm vesicles had roughly a twofold higher specific activity as the non-infected control plants when supplied with 10-15 mM nitrate.

  14. Root canal treatment of a maxillary first premolar with three roots

    OpenAIRE

    Mathew, Josey; Devadathan, Aravindan; Syriac, Gibi; Shamini, Sai

    2015-01-01

    Successful root canal treatment needs a thorough knowledge of both internal and external anatomy of a tooth. Variations in root canal anatomy constitute an impressive challenge to the successful completion of endodontic treatment. Undetected extra roots and canals are a major reason for failed root canal treatment. Three separate roots in a maxillary first premolar have a very low incidence of 0.5?6%. Three rooted premolars are anatomically similar to molars and are sometimes called ?small mo...

  15. Anti-inflammatory activity of 6-hydroxy-2,7-dimethoxy-1,4-henanthraquinone from tuberous roots of yam (Dioscorea batatas) through inhibition of prostaglandin D₂ and leukotriene C₄ production in mouse bone marrow-derived mast cells.

    Science.gov (United States)

    Jin, Meihua; Lu, Yue; Yang, Ju Hye; Jo, Tae Hyung; Park, Young In; Lee, Chong-Kil; Park, Sang-Jo; Son, Kun Ho; Chang, Hyeun Wook

    2011-09-01

    6-Hydroxy-2,7-dimethoxy-1,4-phenanthraquinone (PAQ) isolated from the tuberous roots of Yam (Dioscorea batatas) inhibited cyclooxygenase-2 (COX-2) and cyclooxygenase-1 (COX-1) dependent prostaglandin D(2) (PGD(2)) generation in mouse bone marrow-derived mast cells in a concentration-dependent manner with IC(50) values of 0.08 μM and 0.27 μM, respectively. In the Western blotting with specific anti-COX-2 antibodies, the decrease of the quantity of PGD(2) was accompanied by a decrease in the COX-2 protein level. But PAQ did not affect COX-1 protein level. In addition, this compound inhibited 5-lipoxygenase (5-LOX) dependent production of leukotriene C(4) in a dose-dependent manner, with an IC(50) of 0.032 μM. These results demonstrate that PAQ has a dual COX-2/5-LOX inhibitory activity. This compound also inhibited the degranulation reaction in a dose-dependent manner with an IC(50) of 2.7 μM. Thus, these results suggest that PAQ may be useful in regulating mast cell-mediated inflammatory diseases.

  16. Stress-induced accumulation of wheat germ agglutinin and abscisic acid in roots of wheat seedlings

    International Nuclear Information System (INIS)

    Cammue, B.P.A.; Broekaert, W.F.; Kellens, J.T.C.; Peumans, W.J.; Raikhel, N.V.

    1989-01-01

    Wheat germ agglutinin (WGA) levels in roots of 2-day-old wheat seedlings increased up to three-fold when stressed by air-drying. Similar results were obtained when seedling roots were incubated either in 0.5 molar mannitol or 180 grams per liter polyethylene glycol 6,000, with a peak level of WGA after 5 hours of stress. Longer periods of osmotic treatment resulted in a gradual decline of WGA in the roots. Since excised wheat roots incorporate more [ 35 S]cysteine into WGA under stress conditions, the observed increase of lectin levels is due to de novo synthesis. Measurement of abscisic acid (ABA) levels in roots of control and stressed seedlings indicated a 10-fold increase upon air-drying. Similarly, a five- and seven-fold increase of ABA content of seedling roots was found after 2 hours of osmotic stress by polyethylene glycol 6,000 and mannitol, respectively. Finally, the stress-induced increase of WGA in wheat roots could be inhibited by growing seedlings in the presence of fluridone, an inhibitor of ABA synthesis. These results indicate that roots of water-stressed wheat seedlings (a) contain more WGA as a result of an increased de novo synthesis of this lectin, and (b) exhibit higher ABA levels. The stress-induced increase of lectin accumulation seems to be under control of ABA

  17. Medico-legal aspects of vertical root fractures in root filled teeth

    DEFF Research Database (Denmark)

    Rosen, E; Tsesis, I; Tamse, A

    2012-01-01

    To analyse the medico-legal aspects of vertical root fracture (VRF) following root canal treatment (RCT).......To analyse the medico-legal aspects of vertical root fracture (VRF) following root canal treatment (RCT)....

  18. A new role for glutathione in the regulation of root architecture linked to strigolactones.

    Science.gov (United States)

    Marquez-Garcia, Belen; Njo, Maria; Beeckman, Tom; Goormachtig, Sofie; Foyer, Christine H

    2014-02-01

    Reduced glutathione (GSH) is required for root development, but its functions are not characterized. The effects of GSH depletion on root development were therefore studied in relation to auxin and strigolactone (SL) signalling using a combination of molecular genetic approaches and pharmacological techniques. Lateral root (LR) density was significantly decreased in GSH synthesis mutants (cad2-1, pad2-, rax1-), but not by the GSH synthesis inhibitor, buthionine sulfoximine (BSO). BSO-induced GSH depletion therefore did not influence root architecture in the same way as genetic impairment. Root glutathione contents were similar in the wild-type seedlings and max3-9 and max4-1 mutants that are deficient in SL synthesis and in the SL-signalling mutant, max2-1. BSO-dependent inhibition of GSH synthesis depleted the tissue GSH pool to a similar extent in the wild-type and SL synthesis mutants, with no effect on LR density. The application of the SL analogue GR24 increased root glutathione in the wild-type, max3-9 and max4-1 seedlings, but this increase was absent from max2-1. Taken together, these data establish a link between SLs and the GSH pool that occurs in a MAX2-dependent manner. © 2013 John Wiley & Sons Ltd.

  19. Participation of IAA in transduction of gravistimulus in apical cells of moss protonema

    Science.gov (United States)

    Oksyniuk, U. A.; Khorkavtsiv, O. Y.; Lesniak, Y. I.

    Growth movements of vascular plant axis organs -- photo-, gravi- and other tropisms -- are tightly connected with IAA transport (Hertel, 1983; Medvedev, 1996; Kiss, 2000). Moss protonema synthesizes IAA (indole-3-acetic acid) and transports it basipetally favouring growth and differentiation of caulonema (Bopp, 1979; Rose, Bopp, 1983; Rose et al., 1983). We aimed at studying the role of IAA in moss protonema gravitropism using exogenous IAA, 1-NAA (1-naphthaleneacetic acid), 2,4D (2,4-dichlorophenoxyacetic acid) and inhibitors of polar IAA transport -- phytotropins NPA (N-1-naphthylphthalamic acid) and TIBA (2,3,5-triiodobenzoic acid). Six-day gravitropic protonema of Ceratodon purpureus and Pohlia nutans were taken for experiments. Auxin and phytotropins solutions were laid on protonema mats the latters being kept in solutions for 30 min. Then the surplus of solutions were poured off and Petri dishes were placed vertically for 6 h. 20 μ M of IAA and of other synthetic auxins did not significantly influence the angle of protonema gravity bending, 40 μ M of the agents, howewer, reduced the per cent of apical cells bendings and their angles. The most expressed influence on the angles of bending had the inhibitors of polar IAA transport -- NPA. 0,1 -- 3,0 μ M of this phytotropin did not change the form of apical cell, did not disturb the general distribution of amyloplasts and did not significantly lower the per cent and the value of gravity bending angle, though 10 μ M of the phytotropin - inhibited gravity bending. The mixture of 1-NAA and NPA having been added into the medium the influence of NPA was lowered and gravitropic growth renewed in course of time. 10 μ M of other phytopropin TIBA also inhibited gravitropism of Ceratodon purpureus and Pohlia nutans protonema. The analysis of basipetal transport of IAA in moss rhizoids and protonema may indicate the availability of special IAA transport in these structures (Bopp, Cerier, 1988). On the basis of the

  20. Primary root growth in Arabidopsis thaliana is inhibited by the miR159 mediated repression of MYB33, MYB65 and MYB101.

    Science.gov (United States)

    Xue, Tao; Liu, Zhenhua; Dai, Xuehuan; Xiang, Fengning

    2017-09-01

    Organ growth is a fundamental developmental process basing on cell proliferation and differentiation. The growth of the plant root is sustained by the activity of the root meristem, a process controlled in part by various transcription factors. Here, the miR159 has been identified as a post transcriptional repressor of root growth, on the basis that the mir159ab double mutant developed a larger meristem than did the wild type, and that it formed longer roots. In the mutant, the abundance of MYB33, MYB65 and MYB101 transcript was substantially increased. When MYB33, MYB65 and MYB101 were replaced by the miR159-resistant forms mMYB33, mMYB65 and mMYB101 respectively, the root meristem was similarly enlarged and the growth of the primary root enhanced. MYB65 activity promoted cell division in the root meristem by accelerating the cell cycle. The data suggest that miR159 acts as a key repressor of the primary root's growth, acting through its repression of MYB65 and consequent blocking of the cell cycle. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Accumulation of phenanthrene by roots of intact wheat (Triticum acstivnm L. seedlings: passive or active uptake?

    Directory of Open Access Journals (Sweden)

    Jiang Ting-Hui

    2010-03-01

    Full Text Available Abstract Background Polycyclic aromatic hydrocarbons (PAHs are of particular concern due to their hydrophobic, recalcitrant, persistent, potentially carcinogenic, mutagenic and toxic properties, and their ubiquitous occurrence in the environment. Most of the PAHs in the environment are present in surface soil. Plants grown in PAH-contaminated soils or water can become contaminated with PAHs because of their uptake. Therefore, they may threaten human and animal health. However, the mechanism for PAHs uptake by crop roots is little understood. It is important to understand exactly how PAHs are transported into the plant root system and into the human food chain, since it is beneficial in governing crop contamination by PAHs, remedying soils or waters polluted by PAHs with plants, and modeling potential uptake for risk assessment. Results The possibility that plant roots may take up phenanthrene (PHE, a representative of PAHs, via active process was investigated using intact wheat (Triticum acstivnm L. seedlings in a series of hydroponic experiments. The time course for PHE uptake into wheat roots grown in Hoagland solution containing 5.62 μM PHE for 36 h could be separated into two periods: a fast uptake process during the initial 2 h and a slow uptake component thereafter. Concentration-dependent PHE uptake was characterized by a smooth, saturable curve with an apparent Km of 23.7 μM and a Vmax of 208 nmol g-1 fresh weight h-1, suggesting a carrier-mediated uptake system. Competition between PHE and naphthalene for their uptake by the roots further supported the carrier-mediated uptake system. Low temperature and 2,4-dinitrophenol (DNP could inhibit PHE uptake equally, indicating that metabolism plays a role in PHE uptake. The inhibitions by low temperature and DNP were strengthened with increasing concentration of PHE in external solution within PHE water solubility (7.3 μM. The contribution of active uptake to total absorption was almost 40

  2. The antagonistic regulation of abscisic acid-inhibited root growth by brassinosteroids is partially mediated via direct suppression of ABSCISIC ACID INSENSITIVE 5 expression by BRASSINAZOLE RESISTANT 1.

    Science.gov (United States)

    Yang, Xiaorui; Bai, Yang; Shang, Jianxiu; Xin, Ruijiao; Tang, Wenqiang

    2016-09-01

    Brassinosteroids (BRs) and abscisic acid (ABA) are plant hormones that antagonistically regulate many aspects of plant growth and development; however, the mechanisms that regulate the crosstalk of these two hormones are still not well understood. BRs regulate plant growth and development by activating BRASSINAZOLE RESISTANT 1 (BZR1) family transcription factors. Here we show that the crosstalk between BRs and ABA signalling is partially mediated by BZR1 regulated gene expression. bzr1-1D is a dominant mutant with enhanced BR signalling; our results showed that bzr1-1D mutant is less sensitive to ABA-inhibited primary root growth. By RNA sequencing, a subset of BZR1 regulated ABA-responsive root genes were identified. Of these genes, the expression of a major ABA signalling component ABA INSENSITIVE 5 (ABI5) was found to be suppressed by BR and by BZR1. Additional evidences showed that BZR1 could bind strongly with several G-box cis-elements in the promoter of ABI5, suppress the expression of ABI5 and make plants less sensitive to ABA. Our study demonstrated that ABI5 is a direct target gene of BZR1, and modulating the expression of ABI5 by BZR1 plays important roles in regulating the crosstalk between the BR and ABA signalling pathways. © 2016 John Wiley & Sons Ltd.

  3. Blockade of LGR4 inhibits proliferation and odonto/osteogenic differentiation of stem cells from apical papillae.

    Science.gov (United States)

    Zhou, Meng; Guo, Shuyu; Yuan, Lichan; Zhang, Yuxin; Zhang, Mengnan; Chen, Huimin; Lu, Mengting; Yang, Jianrong; Ma, Junqing

    2017-12-01

    During tooth root development, stem cells from apical papillae (SCAPs) are indispensable, and their abilities of proliferation, migration and odontoblast differentiation are linked to root formation. Leucine-rich repeat-containing GPCR 4 (LGR4) modulates the biological processes of proliferation and differentiation in multiple stem cells. In this study, we showed that LGR4 is expressed in all odontoblast cell lineage cells and Hertwig's epithelial root sheath (HERS) during the mouse root formation in vivo. In vitro we determined that LGR4 is involved in the Wnt/β-catenin signaling pathway regulating proliferation and odonto/osteogenic differentiation of SCAPs. Quantitative reverse-transcription PCR (qRT-PCR) confirmed that LGR4 is expressed during odontogenic differentiation of SCAPs. CCK8 assays and in vitro scratch tests, together with cell cycle flow cytometric analysis, demonstrated that downregulation of LGR4 inhibited SCAPs proliferation, delayed migration and arrested cell cycle progression at the S and G2/M phases. ALP staining revealed that blockade of LGR4 decreased ALP activity. QRT-PCR and Western blot analysis demonstrated that LGR4 silencing reduced the expression of odonto/osteogenic markers (RUNX2, OSX, OPN, OCN and DSPP). Further Western blot and immunofluorescence studies clarified that inhibition of LGR4 disrupted β-catenin stabilization. Taken together, downregulation of LGR4 gene expression inhibited SCAPs proliferation, migration and odonto/osteogenic differentiation by blocking the Wnt/β-catenin signaling pathway. These results indicate that LGR4 might play a vital role in SCAPs proliferation and odontoblastic differentiation.

  4. Proteomic analysis on roots of Oenothera glazioviana under copper-stress conditions.

    Science.gov (United States)

    Wang, Chong; Wang, Jie; Wang, Xiao; Xia, Yan; Chen, Chen; Shen, Zhenguo; Chen, Yahua

    2017-09-06

    Proteomic studies were performed to identify proteins involved in the response of Oenothera glazioviana seedlings under Cu stress. Exposure of 28-d-old seedlings to 50 μM CuSO4 for 3 d led to inhibition of shoot and root growth as well as a considerable increase in the level of lipid peroxidation in the roots. Cu absorbed by O. glazioviana accumulated more easily in the root than in the shoot. Label-free proteomic analysis indicated 58 differentially abundant proteins (DAPs) of the total 3,149 proteins in the roots of O. glazioviana seedlings, of which 36 were upregulated and 22 were downregulated under Cu stress conditions. Gene Ontology analysis showed that most of the identified proteins could be annotated to signal transduction, detoxification, stress defence, carbohydrate, energy, and protein metabolism, development, and oxidoreduction. We also retrieved 13 proteins from the enriched Kyoto Encyclopaedia of Genes and Genomes and the protein-protein interaction databases related to various pathways, including the citric acid (CA) cycle. Application of exogenous CA to O. glazioviana seedlings exposed to Cu alleviated the stress symptoms. Overall, this study provided new insights into the molecular mechanisms of plant response to Cu at the protein level in relation to soil properties.

  5. Root canal irrigants

    OpenAIRE

    Kandaswamy, Deivanayagam; Venkateshbabu, Nagendrababu

    2010-01-01

    Successful root canal therapy relies on the combination of proper instrumentation, irrigation, and obturation of the root canal. Of these three essential steps of root canal therapy, irrigation of the root canal is the most important determinant in the healing of the periapical tissues. The primary endodontic treatment goal must thus be to optimize root canal disinfection and to prevent reinfection. In this review of the literature, various irrigants and the interactions between irrigants are...

  6. ACCERBATIN, a small molecule at the intersection of auxin and reactive oxygen species homeostasis with herbicidal properties

    Czech Academy of Sciences Publication Activity Database

    Hu, Y.; Depaepe, T.; Smet, D.; Hoyerová, Klára; Klíma, Petr; Cuypers, J.; Cutler, S.; Buyst, D.; Morreel, K.; Boerjan, W.; Martins, J.; Petrášek, Jan; Vandenbussche, F.; Van Der Straeten, D.

    2017-01-01

    Roč. 68, č. 15 (2017), s. 4185-4203 ISSN 0022-0957 R&D Projects: GA MŠk LD15137 Institutional support: RVO:61389030 Keywords : apical hook development * root hair development * arabidopsis-thaliana seedlings * ethylene biosynthesis * shoot gravitropism * cell elongation * abiotic stress * abscisic-acid * plant-growth * gene family * Arabidopsis * auxin homeostasis * chemical genetics * ethylene signaling * herbicide * quinoline carboxamide * reactive oxygen species * triple response Subject RIV: EA - Cell Biology OBOR OECD: Plant sciences, botany Impact factor: 5.830, year: 2016

  7. Alfalfa root role in osmotic adjustment under salt stress (abstract)

    International Nuclear Information System (INIS)

    Ibriz, M.; Ghorri, M.; Alami, T.; El Guilli, M.; El- Moidaoui, M.; Benbella, M.

    2005-01-01

    The aim of this work was to evaluate the effect of the sodium chloride on the morpho physiological characteristics of Alfalfa (Medicago sativa L.). The characteristics taken into consideration dry matter production of shoot and root (DMS, DMR), root volume (RV), proline content (PS, PR), included total soluble sugar (SSS; SSR) and chlorophyll a, band (a+b). Salt tolerance of the six genotypes was characterised by capacity to growth in salt environment, buildup of osmoregulating compounds (proline and solubles sugar) and a less inhibition of photosynthesis process (decrease of chlorophyll pigment content). Important genotypes differences were observed for each parameter, which make possible a better understanding of the Alfalfa adaptation mechanisms. The results show that the salt stress has a significant influence on the growth of this plants by decreasing the production of dry matter and :)f the root volume. The most important decreases were clear at the 12 g/l concentration mainly upon the Australian variety (Siriver).Thus the most tolerant to salt stress was the Demnate genotype (Dem04) which presented the lowest decrease percentage. The salt effect upon the plant physiological characteristics causes a decrease of the relative water content and chlorophyll a, b and (a+b) content. It also causes an increase of the relative loss of water, the total soluble sugars (SSS; SSR) and the proline contents (PS, PR). Thus, we found a high correlation between the proline and sugar contents of shoot and root and also between these substances and shoot and root dry matter production. (author)

  8. Light as stress factor to plant roots – case of root halotropism

    Science.gov (United States)

    Yokawa, Ken; Fasano, Rossella; Kagenishi, Tomoko; Baluška, František

    2014-01-01

    Despite growing underground, largely in darkness, roots emerge to be very sensitive to light. Recently, several important papers have been published which reveal that plant roots not only express all known light receptors but also that their growth, physiology and adaptive stress responses are light-sensitive. In Arabidopsis, illumination of roots speeds-up root growth via reactive oxygen species-mediated and F-actin dependent process. On the other hand, keeping Arabidopsis roots in darkness alters F-actin distribution, polar localization of PIN proteins as well as polar transport of auxin. Several signaling components activated by phytohormones are overlapping with light-related signaling cascade. We demonstrated that the sensitivity of roots to salinity is altered in the light-grown Arabidopsis roots. Particularly, light-exposed roots are less effective in their salt-avoidance behavior known as root halotropism. Here we discuss these new aspects of light-mediated root behavior from cellular, physiological and evolutionary perspectives. PMID:25566292

  9. Resistance of red clover (Trifolium pratense) to the root parasitic plant Orobanche minor is activated by salicylate but not by jasmonate.

    Science.gov (United States)

    Kusumoto, Dai; Goldwasser, Yaakov; Xie, Xiaonan; Yoneyama, Kaori; Takeuchi, Yasutomo; Yoneyama, Koichi

    2007-09-01

    Obligate root holoparasites of the genus Orobanche attack dicotyledonous crops and cause severe losses in many parts of the world. Chemical induction of plant defence systems such as systemic acquired resistance was proposed to be an available strategy to control the root parasite, but the detailed mechanisms involved have not been clarified. The aim of this study was to elucidate the effects of salicylic acid (SA), jasmonic acid (JA) and their analogues on resistance of red clover to Orobanche parasitism. Roots of red clover grown in plastic chambers were applied with SA, S-methyl benzo[1,2,3]thiadiazole-7-carbothioate (BTH), methyl jasmonate (MeJA) and n-propyl dihydrojasmonate (PDJ), and then were inoculated with O. minor seeds. Attachments of the parasite were observed after 5 weeks. SA and BTH, inducers of SA-mediated defences, significantly reduced the number of established parasites by more than 75 %. By contrast, MeJA and PDJ, inducers of JA-mediated defences, did not affect parasitism. The reduction in the number of established parasites by SA and BTH was due to the inhibited elongation of O. minor radicles and the activation of defence responses in the host root including lignification of the endodermis. These results suggest that SA-induced resistance, but not JA-induced resistance, is effective in inhibiting Orobanche parasitism and that the resistance is expressed by the host root both externally and internally.

  10. Events Associated with Early Age-Related Decline in Adventitious Rooting Competence of Eucalyptus globulus Labill.

    Science.gov (United States)

    Aumond, Márcio L; de Araujo, Artur T; de Oliveira Junkes, Camila F; de Almeida, Márcia R; Matsuura, Hélio N; de Costa, Fernanda; Fett-Neto, Arthur G

    2017-01-01

    The development of adventitious roots is affected by several factors, including the age of the cutting donor plant, which negatively affects rooting capacity. Eucalyptus globulus quickly loses rooting capacity of cuttings as the donor plant ages, although the molecular and biochemical mechanisms behind this process are still unclear. To better understand the bases of rooting competence loss in E. globulus , the time required for a significant decline in rhizogenic ability without exogenous auxin was determined in microcuttings derived from donor plants of different ages after sowing. Tip cuttings of donor plants were severed before and after loss of rooting competence of microcuttings to test the hypothesis that auxin and carbohydrate homeostasis regulate rooting competence decline. There were no significant changes in concentration of carbohydrates, flavonoids, or proteins before and after the loss of rooting capacity. Peroxidase (EC 1.11.1.7) total activity increased with loss of rooting competence. Auxin concentration showed the opposite pattern. In good agreement, TAA1 , a key gene in auxin biosynthesis, had lower expression after loss of rooting capacity. The same applied to the auxin receptor gene TIR1 , suggesting reduced auxin sensitivity. On the other hand, genes associated with auxin response repression ( TPL , IAA12 ) or with the action of cytokinins, the rhizogenesis inhibitor-related ARR1 , showed higher expression in plants with lower rooting competence. Taken together, data suggest that age negatively affects E. globulus rooting by a combination of factors. Decreased endogenous auxin concentration, possibly caused by less biosynthesis, lower auxin sensitivity, higher expression of genes inhibiting auxin action, as well as of genes related to the action of cytokinins, appear to play roles in this process.

  11. Events Associated with Early Age-Related Decline in Adventitious Rooting Competence of Eucalyptus globulus Labill

    Science.gov (United States)

    Aumond, Márcio L.; de Araujo, Artur T.; de Oliveira Junkes, Camila F.; de Almeida, Márcia R.; Matsuura, Hélio N.; de Costa, Fernanda; Fett-Neto, Arthur G.

    2017-01-01

    The development of adventitious roots is affected by several factors, including the age of the cutting donor plant, which negatively affects rooting capacity. Eucalyptus globulus quickly loses rooting capacity of cuttings as the donor plant ages, although the molecular and biochemical mechanisms behind this process are still unclear. To better understand the bases of rooting competence loss in E. globulus, the time required for a significant decline in rhizogenic ability without exogenous auxin was determined in microcuttings derived from donor plants of different ages after sowing. Tip cuttings of donor plants were severed before and after loss of rooting competence of microcuttings to test the hypothesis that auxin and carbohydrate homeostasis regulate rooting competence decline. There were no significant changes in concentration of carbohydrates, flavonoids, or proteins before and after the loss of rooting capacity. Peroxidase (EC 1.11.1.7) total activity increased with loss of rooting competence. Auxin concentration showed the opposite pattern. In good agreement, TAA1, a key gene in auxin biosynthesis, had lower expression after loss of rooting capacity. The same applied to the auxin receptor gene TIR1, suggesting reduced auxin sensitivity. On the other hand, genes associated with auxin response repression (TPL, IAA12) or with the action of cytokinins, the rhizogenesis inhibitor-related ARR1, showed higher expression in plants with lower rooting competence. Taken together, data suggest that age negatively affects E. globulus rooting by a combination of factors. Decreased endogenous auxin concentration, possibly caused by less biosynthesis, lower auxin sensitivity, higher expression of genes inhibiting auxin action, as well as of genes related to the action of cytokinins, appear to play roles in this process. PMID:29067033

  12. Sorghum root-system classification in contrasting P environments reveals three main rooting types and root-architecture-related marker-trait associations.

    Science.gov (United States)

    Parra-Londono, Sebastian; Kavka, Mareike; Samans, Birgit; Snowdon, Rod; Wieckhorst, Silke; Uptmoor, Ralf

    2018-02-12

    Roots facilitate acquisition of macro- and micronutrients, which are crucial for plant productivity and anchorage in the soil. Phosphorus (P) is rapidly immobilized in the soil and hardly available for plants. Adaptation to P scarcity relies on changes in root morphology towards rooting systems well suited for topsoil foraging. Root-system architecture (RSA) defines the spatial organization of the network comprising primary, lateral and stem-derived roots and is important for adaptation to stress conditions. RSA phenotyping is a challenging task and essential for understanding root development. In this study, 19 traits describing RSA were analysed in a diversity panel comprising 194 sorghum genotypes, fingerprinted with a 90-k single-nucleotide polymorphism (SNP) array and grown under low and high P availability. Multivariate analysis was conducted and revealed three different RSA types: (1) a small root system; (2) a compact and bushy rooting type; and (3) an exploratory root system, which might benefit plant growth and development if water, nitrogen (N) or P availability is limited. While several genotypes displayed similar rooting types in different environments, others responded to P scarcity positively by developing more exploratory root systems, or negatively with root growth suppression. Genome-wide association studies revealed significant quantitative trait loci (P root-system development on chromosomes SBI-02 and SBI-03. Sorghum genotypes with a compact, bushy and shallow root system provide potential adaptation to P scarcity in the field by allowing thorough topsoil foraging, while genotypes with an exploratory root system may be advantageous if N or water is the limiting factor, although such genotypes showed highest P uptake levels under the artificial conditions of the present study. © The Author(s) 2018. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Comparative evaluation of antimicrobial effect of herbal root canal irrigants (Morinda citrifolia, Azadirachta indica, Aloe vera) with sodium hypochlorite: An in vitro study.

    Science.gov (United States)

    Babaji, Prashant; Jagtap, Kiran; Lau, Himani; Bansal, Nandita; Thajuraj, S; Sondhi, Priti

    2016-01-01

    Successful root canal treatment involves the complete elimination of microorganism from the root canal and the three-dimensional obturation of the canal space. Enterococcus faecalis is the most commonly found bacteria in failed root canal. Chemical irrigation of canals along with biomechanical preparation helps in the elimination of microorganisms. The present study was aimed to evaluate the antimicrobial effect of herbal root canal irrigants (Morinda citrifolia, Azadirachta indica extract, Aloe vera) with sodium hypochlorite (NaOCl). The bacterial E. faecalis (ATCC) culture was grown overnight in brain heart infusion (BHI) broth and inoculated in Mueller-Hinton agar plates. Antibacterial inhibition was assessed using agar well diffusion method. All five study irrigants were added to respective wells in agar plates and incubated at 37°C for 24 h. Bacterial inhibition zone around each well was recorded. Results were tabulated and statistically analyzed using Statistical Package for the Social Sciences software for Windows, version 19.0. (IBM Corp., Armonk, NY. Highest inhibitory zone against E. faecalis was seen in NaOCl fallowed by M. citrifolia and A. indica extract, and the least by A. vera extract. Tested herbal medicine (A. indica extract, M. citrifolia, A. vera) showed inhibitory zone against E. faecalis. Hence, these irrigants can be used as root canal irrigating solutions.

  14. Psoralen production in hairy roots and adventitious roots cultures of Psoralea coryfolia.

    Science.gov (United States)

    Baskaran, P; Jayabalan, N

    2009-07-01

    Psoralea corylifolia is an endangered plant producing various compounds of medical importance. Adventitious roots and hairy roots were induced in cultures prepared from hypocotyl explants. Psoralen content was evaluated in both root types grown either in suspension cultures or on agar solidified medium. Psoralen content was approximately 3 mg g(-1) DW in suspension grown hairy roots being higher than in solid grown hairy roots and in solid and suspension-grown adventitious roots.

  15. Nonsurgical management of horizontal root fracture associated external root resorption and internal root resorption

    Directory of Open Access Journals (Sweden)

    Shiraz Pasha

    2016-01-01

    Full Text Available Horizontal root fractures, which frequently affect the upper incisors, usually result from a frontal impact. As a result, combined injuries occur in dental tissues such as the pulp, dentin, cementum, periodontal ligament, and alveolar bone. Internal root canal inflammatory resorption involves a progressive loss of intraradicular dentin without adjunctive deposition of hard tissues adjacent to the resorptive sites. It is frequently associated with chronic pulpal inflammation, and bacteria might be identified from the granulation tissues when the lesion is progressive to the extent that it is identifiable with routine radiographs. With the advancement in technology, it is imperative to use modern diagnostic tools such as cone beam computed tomography and radiovisuography to diagnose and confirm the presence and extent of resorptions and fractures and their exact location. This case report presents a rare case having internal root resorption and horizontal root fracture with external inflammatory root resorption both which were treated successfully following guidelines by International Association of Dental Traumatology by nonsurgical treatment with 1 year follow-up.

  16. Effects of fluoride and 6 benzylaminopurine on growth and respiration of corn and cotton roots

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, C R

    1967-01-01

    Corn and cotton plants exhibit a wide difference in their susceptibility to atmospheric fluoride. Corn shows leaf lesions when 100 ..gamma../gm on a dry weight basis are accumulated but cotton can tolerate 5000 ..gamma../gm without showing leaf necrosis. A comparison of respirational response of potted seedlings of the two species to 10 ..gamma../M/sup 3/ HF caused an increase of about 10%. Addition of 2 x 10/sup 2/M F/sup -/ to solutions for germinating the plants showed that cotton accumulated about twice as much as F/sup -/ in seedling roots. Growth was reduced about one half by 2 x 10/sup -3/M F/sup -/ in both species but respirational rates of root tips from control and fluoride treated tissues were equal. Prolonged treatment of excised root tips with fluoride reduced respiration. Because fluoride causes cellular changes in roots similar to aging and kinetin seems to act to reverse these changes, corn was germinated with 2 x 10/sup -3/M F/sup -/ and increasing levels of 6-benzylaminopurine. Root growth inhibition (63%) was reversed significantly at 0.2 - 0.8..gamma.. ml. Respirational rates of root tips grown in fluoride, fluoride plus 6-benzylaminopurine and controls were equal.

  17. ROOT Reference Documentation

    CERN Document Server

    Fuakye, Eric Gyabeng

    2017-01-01

    A ROOT Reference Documentation has been implemented to generate all the lists of libraries needed for each ROOT class. Doxygen has no option to generate or add the lists of libraries for each ROOT class. Therefore shell scripting and a basic C++ program was employed to import the lists of libraries needed by each ROOT class.

  18. Root signals that mediate mutualistic interactions in the rhizosphere.

    Science.gov (United States)

    Rasmann, Sergio; Turlings, Ted Cj

    2016-08-01

    A recent boom in research on belowground ecology is rapidly revealing a multitude of fascinating interactions, in particular in the rhizosphere. Many of these interactions are mediated by photo-assimilates that are excreted by plant roots. Root exudates are not mere waste products, but serve numerous functions to control abiotic and biotic processes. These functions range from changing the chemical and physical properties of the soil, inhibiting the growth of competing plants, combatting herbivores, and regulating the microbial community. Particularly intriguing are root-released compounds that have evolved to serve mutualistic interactions with soil-dwelling organisms. These mutually beneficial plant-mediated signals are not only of fundamental ecological interest, but also exceedingly important from an agronomical perspective. Here, we attempt to provide an overview of the plant-produced compounds that have so far been implicated in mutualistic interactions. We propose that these mutualistic signals may have evolved from chemical defenses and we point out that they can be (mis)used by specialized pathogens and herbivores. We speculate that many more signals and interactions remain to be uncovered and that a good understanding of the mechanisms and ecological implications can be the basis for exploitation and manipulation of the signals for crop improvement and protection. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. X-ray computed tomography uncovers root-root interactions: quantifying spatial relationships between interacting root systems in three dimensions.

    Science.gov (United States)

    Paya, Alexander M; Silverberg, Jesse L; Padgett, Jennifer; Bauerle, Taryn L

    2015-01-01

    Research in the field of plant biology has recently demonstrated that inter- and intra-specific interactions belowground can dramatically alter root growth. Our aim was to answer questions related to the effect of inter- vs. intra-specific interactions on the growth and utilization of undisturbed space by fine roots within three dimensions (3D) using micro X-ray computed tomography. To achieve this, Populus tremuloides (quaking aspen) and Picea mariana (black spruce) seedlings were planted into containers as either solitary individuals, or inter-/intra-specific pairs, allowed to grow for 2 months, and 3D metrics developed in order to quantify their use of belowground space. In both aspen and spruce, inter-specific root interactions produced a shift in the vertical distribution of the root system volume, and deepened the average position of root tips when compared to intra-specifically growing seedlings. Inter-specific interactions also increased the minimum distance between root tips belonging to the same root system. There was no effect of belowground interactions on the radial distribution of roots, or the directionality of lateral root growth for either species. In conclusion, we found that significant differences were observed more often when comparing controls (solitary individuals) and paired seedlings (inter- or intra-specific), than when comparing inter- and intra-specifically growing seedlings. This would indicate that competition between neighboring seedlings was more responsible for shifting fine root growth in both species than was neighbor identity. However, significant inter- vs. intra-specific differences were observed, which further emphasizes the importance of biological interactions in competition studies.

  20. Root hairs aid soil penetration by anchoring the root surface to pore walls.

    Science.gov (United States)

    Bengough, A Glyn; Loades, Kenneth; McKenzie, Blair M

    2016-02-01

    The physical role of root hairs in anchoring the root tip during soil penetration was examined. Experiments using a hairless maize mutant (Zea mays: rth3-3) and its wild-type counterpart measured the anchorage force between the primary root of maize and the soil to determine whether root hairs enabled seedling roots in artificial biopores to penetrate sandy loam soil (dry bulk density 1.0-1.5g cm(-3)). Time-lapse imaging was used to analyse root and seedling displacements in soil adjacent to a transparent Perspex interface. Peak anchorage forces were up to five times greater (2.5N cf. 0.5N) for wild-type roots than for hairless mutants in 1.2g cm(-3) soil. Root hair anchorage enabled better soil penetration for 1.0 or 1.2g cm(-3) soil, but there was no significant advantage of root hairs in the densest soil (1.5g cm(-3)). The anchorage force was insufficient to allow root penetration of the denser soil, probably because of less root hair penetration into pore walls and, consequently, poorer adhesion between the root hairs and the pore walls. Hairless seedlings took 33h to anchor themselves compared with 16h for wild-type roots in 1.2g cm(-3) soil. Caryopses were often pushed several millimetres out of the soil before the roots became anchored and hairless roots often never became anchored securely.The physical role of root hairs in anchoring the root tip may be important in loose seed beds above more compact soil layers and may also assist root tips to emerge from biopores and penetrate the bulk soil. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  1. Measurements of water uptake of maize roots: the key function of lateral roots

    Science.gov (United States)

    Ahmed, M. A.; Zarebanadkouki, M.; Kroener, E.; Kaestner, A.; Carminati, A.

    2014-12-01

    Maize (Zea mays L.) is one of the most important crop worldwide. Despite its importance, there is limited information on the function of different root segments and root types of maize in extracting water from soils. Therefore, the aim of this study was to investigate locations of root water uptake in maize. We used neutron radiography to: 1) image the spatial distribution of maize roots in soil and 2) trace the transport of injected deuterated water (D2O) in soil and roots. Maizes were grown in aluminum containers (40×38×1 cm) filled with a sandy soil. When the plants were 16 days old, we injected D2O into selected soil regions containing primary, seminal and lateral roots. The experiments were performed during the day (transpiring plants) and night (not transpiring plants). The transport of D2O into roots was simulated using a new convection-diffusion numerical model of D2O transport into roots. By fitting the observed D2O transport we quantified the diffusional permeability and the water uptake of the different root segments. The maize root architecture consisted of a primary root, 4-5 seminal roots and many lateral roots connected to the primary and seminal roots. Laterals emerged from the proximal 15 cm of the primary and seminal roots. Water uptake occurred primarily in lateral roots. Lateral roots had the highest diffusional permeability (9.4×10-7), which was around six times higher that the diffusional permeability of the old seminal segments (1.4×10-7), and two times higher than the diffusional permeability of the young seminal segments (4.7×10-7). The radial flow of D2O into the lateral (6.7×10-5 ) was much higher than in the young seminal roots (1.1×10-12). The radial flow of D2O into the old seminal was negligible. We concluded that the function of the primary and seminal roots was to collect water from the lateral roots and transport it to the shoot. A maize root system with lateral roots branching from deep primary and seminal roots would be

  2. A Co-Opted Hormonal Cascade Activates Dormant Adventitious Root Primordia upon Flooding in Solanum dulcamara1[OPEN

    Science.gov (United States)

    Dawood, Thikra; Kensche, Philip R.; Cristescu, Simona M.; Mariani, Celestina

    2016-01-01

    Soil flooding is a common stress factor affecting plants. To sustain root function in the hypoxic environment, flooding-tolerant plants may form new, aerenchymatous adventitious roots (ARs), originating from preformed, dormant primordia on the stem. We investigated the signaling pathway behind AR primordium reactivation in the dicot species Solanum dulcamara. Transcriptome analysis indicated that flooding imposes a state of quiescence on the stem tissue, while increasing cellular activity in the AR primordia. Flooding led to ethylene accumulation in the lower stem region and subsequently to a drop in abscisic acid (ABA) level in both stem and AR primordia tissue. Whereas ABA treatment prevented activation of AR primordia by flooding, inhibition of ABA synthesis was sufficient to activate them in absence of flooding. Together, this reveals that there is a highly tissue-specific response to reduced ABA levels. The central role for ABA in the response differentiates the pathway identified here from the AR emergence pathway known from rice (Oryza sativa). Flooding and ethylene treatment also induced expression of the polar auxin transporter PIN2, and silencing of this gene or chemical inhibition of auxin transport inhibited primordium activation, even though ABA levels were reduced. Auxin treatment, however, was not sufficient for AR emergence, indicating that the auxin pathway acts in parallel with the requirement for ABA reduction. In conclusion, adaptation of S. dulcamara to wet habitats involved co-option of a hormonal signaling cascade well known to regulate shoot growth responses, to direct a root developmental program upon soil flooding. PMID:26850278

  3. New sesquiterpene lactones from sunflower root exudate as germination stimulants for Orobanche cumana.

    Science.gov (United States)

    Raupp, Frank M; Spring, Otmar

    2013-11-06

    Orobanche cumana is a serious threat for cultivation of sunflower in Europe and Asia. Germination of the parasite is induced by metabolites released from the host root system. The first germination stimulant from sunflower root exudate was recently identified as dehydrocostus lactone, a sesquiterpene lactone. Bioassay-guided fractionation of root exudates now showed the release of additional sesquiterpene lactones. Besides dehydrocostus lactone, costunolide, tomentosin, and 8-epixanthatin were purified and identified spectroscopically. All four compounds induced germination of O. cumana at nano- to micromolar concentrations. Costunolide and dehydrocostus lactone concentrations above 1 μM reduced the activity, and application of 100 μM inhibited germination irreversibly. Seeds of Phelipanche ramosa could not be induced with costunolide. O. cumana seeds also germinated with GR24, a synthetic strigolactone. No bioactive fraction of sunflower contained compounds of this type. This supports previous findings that sesquiterpene lactones instead of strigolactones trigger the sunflower/O. cumana interaction.

  4. Gel-free/label-free proteomic analysis of root tip of soybean over time under flooding and drought stresses.

    Science.gov (United States)

    Wang, Xin; Oh, MyeongWon; Sakata, Katsumi; Komatsu, Setsuko

    2016-01-01

    Growth in the early stage of soybean is markedly inhibited under flooding and drought stresses. To explore the responsive mechanisms of soybean, temporal protein profiles of root tip under flooding and drought stresses were analyzed using gel-free/label-free proteomic technique. Root tip was analyzed because it was the most sensitive organ against flooding, and it was beneficial to root penetration under drought. UDP glucose: glycoprotein glucosyltransferase was decreased and increased in soybean root under flooding and drought, respectively. Temporal protein profiles indicated that fermentation and protein synthesis/degradation were essential in root tip under flooding and drought, respectively. In silico protein-protein interaction analysis revealed that the inductive and suppressive interactions between S-adenosylmethionine synthetase family protein and B-S glucosidase 44 under flooding and drought, respectively, which are related to carbohydrate metabolism. Furthermore, biotin/lipoyl attachment domain containing protein and Class II aminoacyl tRNA/biotin synthetases superfamily protein were repressed in the root tip during time-course stresses. These results suggest that biotin and biotinylation might be involved in energy management to cope with flooding and drought in early stage of soybean-root tip. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Characterization of transport of calcium by microsomal membranes from roots maize

    International Nuclear Information System (INIS)

    Vaughan, M.A.

    1985-01-01

    This study investigates calcium transport by membranes of roots of maize isolated by differential centrifugation. The preparation was determined to be enriched in plasma membrane using market enzyme and electron microscopy. Using the 45 Ca filtration technique and liquid scintillation counting, vesicular calcium uptake was shown to be stimulated by added calmodulin and specific for and dependent on ATP. Conditions for maximal calcium accumulation were found to be 30 min incubation in the presence of 5 mM ATP, 5 mM MgCl 2 , 50 μM CaCl 2 , at 23 0 C, and at pH 6.5. Calcium uptake was inhibited by the ionophores A23187, X-537A, and ionomycin. Sodium fluoride, ruthenium red, and p-chloromercuribenzoate completely inhibited transport: diamide and vanadate produced slight inhibition; caffeine, caffeic acid, oligomycin, and ouabain produced little or no inhibition. Chlorpromazine, W7, trifluoperazine, and R 24 571 inhibit calcium uptake irrespective of added calmodulin, while W5 showed little effect on uptake. Verapamil, nifedipine, cinnarizine, flunarizine, lidoflazine, and diltiazem decreased calcium uptake by 17%-50%. Electron microscopic localization of calcium by pyroantimonate showed vesicles incubated with calmodulin and ATP showed the greatest amount of precipitate. These results suggest that these vesicles accumulate calcium in an ATP-dependent, calmodulin-stimulated manner

  6. Conjoined lumbosacral nerve roots

    International Nuclear Information System (INIS)

    Kyoshima, Kazumitsu; Nishiura, Iwao; Koyama, Tsunemaro

    1986-01-01

    Several kinds of the lumbosacral nerve root anomalies have already been recognized, and the conjoined nerve roots is the most common among them. It does not make symptoms by itself, but if there is a causation of neural entrapment, for example, disc herniation, lateral recessus stenosis, spondylolisthesis, etc., so called ''biradicular syndrome'' should occur. Anomalies of the lumbosacral nerve roots, if not properly recognized, may lead to injury of these nerves during operation of the lumbar spine. Recently, the chance of finding these anomalous roots has been increased more and more with the use of metrizamide myelography and metrizamide CT, because of the improvement of the opacification of nerve roots. We describe the findings of the anomalous roots as revealed by these two methods. They demonstrate two nerve roots running parallel and the asymmetrical wide root sleeve. Under such circumstances, it is important to distinguish the anomalous roots from the normal ventral and dorsal roots. (author)

  7. Role of hormones in controlling vascular differentiation and the mechanism of lateral root initiation.

    Science.gov (United States)

    Aloni, Roni

    2013-11-01

    The vascular system in plants is induced and controlled by streams of inductive hormonal signals. Auxin produced in young leaves is the primary controlling signal in vascular differentiation. Its polar and non-polar transport pathways and major controlling mechanisms are clarified. Ethylene produced in differentiating protoxylem vessels is the signal that triggers lateral root initiation, while tumor-induced ethylene is a limiting and controlling factor of crown gall development and its vascular differentiation. Gibberellin produced in mature leaves moves non-polarly and promotes elongation, regulates cambium activity and induces long fibers. Cytokinin from the root cap moves upward to promote cambial activity and stimulate shoot growth and branching, while strigolactone from the root inhibits branching. Furthermore, the role of the hormonal signals in controlling the type of differentiating vascular elements and gradients of conduit size and density, and how they regulate plant adaptation and have shaped wood evolution are elucidated.

  8. IAA transport in corn roots includes the root cap

    International Nuclear Information System (INIS)

    Hasenstein, K.H.

    1989-01-01

    In earlier reports we concluded that auxin is the growth regulator that controls gravicurvature in roots and that the redistribution of auxin occurs within the root cap. Since other reports did not detect auxin in the root cap, we attempted to confirm the IAA does move through the cap. Agar blocks containing 3 H-IAA were applied to the cut surface of 5 mm long apical segments of primary roots of corn (mo17xB73). After 30 to 120 min radioactivity (RA) of the cap and root tissue was determined. While segments suspended in water-saturated air accumulated very little RA in the cap, application of 0.5 μ1 of dist. water to the cap (=controls) increased RA of the cap dramatically. Application to the cap of 0.5 μ1 of sorbitol or the Ca 2+ chelator EGTA reduced cap RA to 46% and 70% respectively compared to water, without affecting uptake. Control root segments gravireacted faster than non-treated or osmoticum or EGTA treated segments. The data indicate that both the degree of hydration and calcium control the amount of auxin moving through the cap

  9. Plant-microbe rhizosphere interactions mediated by Rehmannia glutinosa root exudates under consecutive monoculture

    Science.gov (United States)

    Wu, Linkun; Wang, Juanying; Huang, Weimin; Wu, Hongmiao; Chen, Jun; Yang, Yanqiu; Zhang, Zhongyi; Lin, Wenxiong

    2015-10-01

    Under consecutive monoculture, the biomass and quality of Rehmannia glutinosa declines significantly. Consecutive monoculture of R. glutinosa in a four-year field trial led to significant growth inhibition. Most phenolic acids in root exudates had cumulative effects over time under sterile conditions, but these effects were not observed in the rhizosphere under monoculture conditions. It suggested soil microbes might be involved in the degradation and conversion of phenolic acids from the monocultured plants. T-RFLP and qPCR analysis demonstrated differences in both soil bacterial and fungal communities during monoculture. Prolonged monoculture significantly increased levels of Fusarium oxysporum, but decreased levels of Pseudomonas spp. Abundance of beneficial Pseudomonas spp. with antagonistic activity against F. oxysporum was lower in extended monoculture soils. Phenolic acid mixture at a ratio similar to that found in the rhizosphere could promote mycelial growth, sporulation, and toxin (3-Acetyldeoxynivalenol, 15-O-Acetyl-4-deoxynivalenol) production of pathogenic F. oxysporum while inhibiting growth of the beneficial Pseudomonas sp. W12. This study demonstrates that extended monoculture can alter the microbial community of the rhizosphere, leading to relatively fewer beneficial microorganisms and relatively more pathogenic and toxin-producing microorganisms, which is mediated by the root exudates.

  10. Incorporation of carbohydrate residues into peroxidase isoenzymes in horseradish roots.

    Science.gov (United States)

    Lew, J Y; Shannon, L M

    1973-11-01

    Sliced root tissue of the horseradish plant (Armoracia rusticana), when incubated with mannose-U-(14)C, incorporated radioactivity into peroxidase isoenzymes. Over 90% of the radioactivity in the highly purified peroxidase isoenzymes was present in the neutral sugar residues of the molecule, i.e. fucose, arabinose, xylose, mannose. When the root slices were incubated simultaneously with leucine-4,5-(3)H and mannose-U-(14)C, cycloheximide strongly inhibited leucine incorporation into the peptide portion of peroxidase isoenzymes but had little effect on the incorporation of (14)C into the neutral sugars. These results indicated that synthesis of the peptide portion of peroxidase was completed before the monosaccharide residues were attached to the molecule. This temporal relationship between the synthesis of protein and the attachment of carbohydrate residues in the plant glycoprotein, horseradish peroxidase, appears to be similar to that reported for glycoprotein biosynthesis in many mammalian systems.

  11. Root anatomical phenes predict root penetration ability and biomechanical properties in maize (Zea Mays)

    OpenAIRE

    Chimungu, Joseph G.; Loades, Kenneth W.; Lynch, Jonathan P.

    2015-01-01

    The ability of roots to penetrate hard soil is important for crop productivity but specific root phenes contributing to this ability are poorly understood. Root penetrability and biomechanical properties are likely to vary in the root system dependent on anatomical structure. No information is available to date on the influence of root anatomical phenes on root penetrability and biomechanics. Root penetration ability was evaluated using a wax layer system. Root tensile and bending strength we...

  12. GLO-Roots: an imaging platform enabling multidimensional characterization of soil-grown root systems

    Science.gov (United States)

    Rellán-Álvarez, Rubén; Lobet, Guillaume; Lindner, Heike; Pradier, Pierre-Luc; Sebastian, Jose; Yee, Muh-Ching; Geng, Yu; Trontin, Charlotte; LaRue, Therese; Schrager-Lavelle, Amanda; Haney, Cara H; Nieu, Rita; Maloof, Julin; Vogel, John P; Dinneny, José R

    2015-01-01

    Root systems develop different root types that individually sense cues from their local environment and integrate this information with systemic signals. This complex multi-dimensional amalgam of inputs enables continuous adjustment of root growth rates, direction, and metabolic activity that define a dynamic physical network. Current methods for analyzing root biology balance physiological relevance with imaging capability. To bridge this divide, we developed an integrated-imaging system called Growth and Luminescence Observatory for Roots (GLO-Roots) that uses luminescence-based reporters to enable studies of root architecture and gene expression patterns in soil-grown, light-shielded roots. We have developed image analysis algorithms that allow the spatial integration of soil properties, gene expression, and root system architecture traits. We propose GLO-Roots as a system that has great utility in presenting environmental stimuli to roots in ways that evoke natural adaptive responses and in providing tools for studying the multi-dimensional nature of such processes. DOI: http://dx.doi.org/10.7554/eLife.07597.001 PMID:26287479

  13. ROOT.NET: Using ROOT from .NET languages like C# and F#

    Science.gov (United States)

    Watts, G.

    2012-12-01

    ROOT.NET provides an interface between Microsoft's Common Language Runtime (CLR) and .NET technology and the ubiquitous particle physics analysis tool, ROOT. ROOT.NET automatically generates a series of efficient wrappers around the ROOT API. Unlike pyROOT, these wrappers are statically typed and so are highly efficient as compared to the Python wrappers. The connection to .NET means that one gains access to the full series of languages developed for the CLR including functional languages like F# (based on OCaml). Many features that make ROOT objects work well in the .NET world are added (properties, IEnumerable interface, LINQ compatibility, etc.). Dynamic languages based on the CLR can be used as well, of course (Python, for example). Additionally it is now possible to access ROOT objects that are unknown to the translation tool. This poster will describe the techniques used to effect this translation, along with performance comparisons, and examples. All described source code is posted on the open source site CodePlex.

  14. ROOT.NET: Using ROOT from .NET languages like C and F

    International Nuclear Information System (INIS)

    Watts, G

    2012-01-01

    ROOT.NET provides an interface between Microsoft's Common Language Runtime (CLR) and .NET technology and the ubiquitous particle physics analysis tool, ROOT. ROOT.NET automatically generates a series of efficient wrappers around the ROOT API. Unlike pyROOT, these wrappers are statically typed and so are highly efficient as compared to the Python wrappers. The connection to .NET means that one gains access to the full series of languages developed for the CLR including functional languages like F (based on OCaml). Many features that make ROOT objects work well in the .NET world are added (properties, IEnumerable interface, LINQ compatibility, etc.). Dynamic languages based on the CLR can be used as well, of course (Python, for example). Additionally it is now possible to access ROOT objects that are unknown to the translation tool. This poster will describe the techniques used to effect this translation, along with performance comparisons, and examples. All described source code is posted on the open source site CodePlex.

  15. Radiotherapy Suppresses Bone Cancer Pain through Inhibiting Activation of cAMP Signaling in Rat Dorsal Root Ganglion and Spinal Cord

    Directory of Open Access Journals (Sweden)

    Guiqin Zhu

    2016-01-01

    Full Text Available Radiotherapy is one of the major clinical approaches for treatment of bone cancer pain. Activation of cAMP-PKA signaling pathway plays important roles in bone cancer pain. Here, we examined the effects of radiotherapy on bone cancer pain and accompanying abnormal activation of cAMP-PKA signaling. Female Sprague-Dawley rats were used and received tumor cell implantation (TCI in rat tibia (TCI cancer pain model. Some of the rats that previously received TCI treatment were treated with X-ray radiation (radiotherapy. Thermal hyperalgesia and mechanical allodynia were measured and used for evaluating level of pain caused by TCI treatment. PKA mRNA expression in dorsal root ganglion (DRG was detected by RT-PCR. Concentrations of cAMP, IL-1β, and TNF-α as well as PKA activity in DRG and the spinal cord were measured by ELISA. The results showed that radiotherapy significantly suppressed TCI-induced thermal hyperalgesia and mechanical allodynia. The level of PKA mRNA in DRG, cAMP concentration and PKA activity in DRG and in the spinal cord, and concentrations of IL-1β and TNF-α in the spinal cord were significantly reduced by radiotherapy. In addition, radiotherapy also reduced TCI-induced bone loss. These findings suggest that radiotherapy may suppress bone cancer pain through inhibition of activation of cAMP-PKA signaling pathway in DRG and the spinal cord.

  16. Locally Finite Root Supersystems

    OpenAIRE

    Yousofzadeh, Malihe

    2013-01-01

    We introduce the notion of locally finite root supersystems as a generalization of both locally finite root systems and generalized root systems. We classify irreducible locally finite root supersystems.

  17. Possible role of glutamine synthetase in the NO signaling response in root nodules by contributing to the antioxidant defenses

    Directory of Open Access Journals (Sweden)

    Liliana Santos Silva

    2013-09-01

    Full Text Available Nitric oxide (NO is emerging as an important regulatory player in the Rhizobium-legume symbiosis. The occurrence of NO during several steps of the symbiotic interaction suggests an important, but yet unknown, signaling role of this molecule for root nodule formation and functioning. The identification of the molecular targets of NO is key for the assembly of the signal transduction cascade that will ultimately help to unravel NO function. We have recently shown that the key nitrogen assimilatory enzyme Glutamine Synthetase (GS is a molecular target of NO in root nodules of Medicago truncatula, being post-translationally regulated by tyrosine nitration in relation to nitrogen fixation. In functional nodules of M. truncatula NO formation has been located in the bacteroid containing cells of the fixation zone, where the ammonium generated by bacterial nitrogenase is released to the plant cytosol and assimilated into the organic pools by plant GS. We propose that the NO-mediated GS post-translational inactivation is connected to nitrogenase inhibition induced by NO and is related to metabolite channeling to boost the nodule antioxidant defenses. Glutamate, a substrate for GS activity is also the precursor for the synthesis of glutathione (GSH, which is highly abundant in root nodules of several plant species and known to play a major role in the antioxidant defense participating in the ascorbate/GSH cycle. Existing evidence suggests that upon NO-mediated GS inhibition, glutamate could be channeled for the synthesis of GSH. According to this hypothesis, GS would be involved in the NO-signaling responses in root nodules and the NO-signaling events would meet the nodule metabolic pathways to provide an adaptive response to the inhibition of symbiotic nitrogen fixation by reactive nitrogen species (RNS.

  18. Saikosaponin D Isolated from Bupleurum falcatum Inhibits Selectin-Mediated Cell Adhesion

    Directory of Open Access Journals (Sweden)

    Myoung-Jun Jang

    2014-12-01

    Full Text Available Three saikosaponins were isolated from the MeOH extract of the roots of Bupleurum falcatum L.: saikosaponins B3 (1; B4 (2; and D (3. Of the three, compound 3 inhibited the interaction of selectins (E, L, and P and THP-1 cells with IC50 values of 1.8, 3.0 and 4.3 µM, respectively. Also, the aglycone structure 4 of compound 3 showed moderate inhibitory activity on L-selectin-mediated cell adhesion. From these results, we suspect that compound 3 isolated from Bupleurum falcatum roots would be a good candidate for therapeutic strategies to treat inflammation.

  19. Descendant root volume varies as a function of root type: estimation of root biomass lost during uprooting in Pinus pinaster

    OpenAIRE

    Danjon, Frédéric; Caplan, Joshua S.; Fortin, Mathieu; Meredieu, Céline

    2013-01-01

    Root systems of woody plants generally display a strong relationship between the cross-sectional area or cross-sectional diameter (CSD) of a root and the dry weight of biomass (DWd) or root volume (Vd) that has grown (i.e., is descendent) from a point. Specification of this relationship allows one to quantify root architectural patterns and estimate the amount of material lost when root systems are extracted from the soil. However, specifications of this relationship generally do not account ...

  20. Effects of adhesions of amorphous Fe and Al hydroxides on surface charge and adsorption of K+ and Cd2+ on rice roots.

    Science.gov (United States)

    Liu, Zhao-Dong; Wang, Hai-Cui; Zhou, Qin; Xu, Ren-Kou

    2017-11-01

    Iron (Fe) and aluminum (Al) hydroxides in variable charge soils attached to rice roots may affect surface-charge properties and subsequently the adsorption and uptake of nutrients and toxic metals by the roots. Adhesion of amorphous Fe and Al hydroxides onto rice roots and their effects on zeta potential of roots and adsorption of potassium (K + ) and cadmium (Cd 2+ ) by roots were investigated. Rice roots adsorbed more Al hydroxide than Fe hydroxide because of the greater positive charge on Al hydroxide. Adhesion of Fe and Al hydroxides decreased the negative charge on rice roots, and a greater effect of the Al hydroxide. Consequently, adhesion of Fe and Al hydroxides reduced the K + and Cd 2+ adsorption by rice roots. The results of attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and desorption of K + and Cd 2+ from rice roots indicated that physical masking by Fe and Al hydroxides and diffuse-layer overlapping between the positively-charged hydroxides and negatively-charged roots were responsible for the reduction of negative charge on roots induced by adhesion of the hydroxides. Therefore, the interaction between Fe and Al hydroxides and rice roots reduced negative charge on roots and thus inhibited their adsorption of nutrient and toxic cations. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Antioxidant Properties of Berberis aetnensis C. Presl (Berberidaceae Roots Extract and Protective Effects on Astroglial Cell Cultures

    Directory of Open Access Journals (Sweden)

    Agata Campisi

    2014-01-01

    Full Text Available Berberis aetnensis C. Presl (Berberidaceae is a bushy-spiny shrub common on Mount Etna (Sicily. We demonstrated that the alkaloid extract of roots of B. aetnensis C. Presl contains prevalently berberine and berbamine, possesses antimicrobial properties, and was able to counteract the upregulation evoked by glutamate of tissue transglutaminase in primary rat astroglial cell cultures. Until now, there are no reports regarding antioxidant properties of B. aetnensis C. Presl collected in Sicily. Air-dried, powdered roots of B. aetnensis C. Presl were extracted, identified, and quantified by HPLC. We assessed in cellular free system its effect on superoxide anion, radicals scavenging activity of antioxidants against free radicals like the 1,1-diphenyl-2-picrylhydrazyl radical, and the inhibition of xanthine oxidase activity. In primary rat astroglial cell cultures, exposed to glutamate, we evaluated the effect of the extract on glutathione levels and on intracellular production of reactive oxygen species generated by glutamate. The alkaloid extract of B. aetnensis C. Presl inhibited superoxide anion, restored to control values, the decrease of GSH levels, and the production of reactive oxygen species. Potent antioxidant activities of the alkaloid extract of roots of B. aetnensis C. Presl may be one of the mechanisms by which the extract is effective against health disorders associated to oxidative stress.

  2. Antioxidant properties of Berberis aetnensis C. Presl (Berberidaceae) roots extract and protective effects on astroglial cell cultures.

    Science.gov (United States)

    Campisi, Agata; Acquaviva, Rosaria; Bonfanti, Roberta; Raciti, Giuseppina; Amodeo, Andrea; Mastrojeni, Silvana; Ragusa, Salvatore; Iauk, Liliana

    2014-01-01

    Berberis aetnensis C. Presl (Berberidaceae) is a bushy-spiny shrub common on Mount Etna (Sicily). We demonstrated that the alkaloid extract of roots of B. aetnensis C. Presl contains prevalently berberine and berbamine, possesses antimicrobial properties, and was able to counteract the upregulation evoked by glutamate of tissue transglutaminase in primary rat astroglial cell cultures. Until now, there are no reports regarding antioxidant properties of B. aetnensis C. Presl collected in Sicily. Air-dried, powdered roots of B. aetnensis C. Presl were extracted, identified, and quantified by HPLC. We assessed in cellular free system its effect on superoxide anion, radicals scavenging activity of antioxidants against free radicals like the 1,1-diphenyl-2-picrylhydrazyl radical, and the inhibition of xanthine oxidase activity. In primary rat astroglial cell cultures, exposed to glutamate, we evaluated the effect of the extract on glutathione levels and on intracellular production of reactive oxygen species generated by glutamate. The alkaloid extract of B. aetnensis C. Presl inhibited superoxide anion, restored to control values, the decrease of GSH levels, and the production of reactive oxygen species. Potent antioxidant activities of the alkaloid extract of roots of B. aetnensis C. Presl may be one of the mechanisms by which the extract is effective against health disorders associated to oxidative stress.

  3. Roots & Hollers

    OpenAIRE

    Kollman, Patrick L; Gorman, Thomas A

    2011-01-01

    Roots & Hollers, 2011 A documentary by Thomas Gorman & Patrick Kollman Master’s Project Abstract: Roots & Hollers uncovers the wild American ginseng trade, revealing a unique intersection between Asia and rural America. Legendary in Asia for its healing powers, ginseng helps sustain the livelihoods of thousands in Appalachia. A single root can sell for thousands of dollars at auction. Shot on-location in the mountains of Kentucky and West Virginia, this student doc...

  4. Calcium-regulated in vivo protein phosphorylation in Zea mays L. root tips

    Science.gov (United States)

    Raghothama, K. G.; Reddy, A. S.; Friedmann, M.; Poovaiah, B. W.

    1987-01-01

    Calcium dependent protein phosphorylation was studied in corn (Zea mays L.) root tips. Prior to in vivo protein phosphorylation experiments, the effect of calcium, ethyleneglycol-bis-(beta-aminoethyl ether)-N-N' -tetraacetic acid (EGTA) and calcium ionophore (A-23187) on phosphorus uptake was studied. Calcium increased phosphorus uptake, whereas EGTA and A-23187 decreased it. Consequently, phosphorus concentration in the media was adjusted so as to attain similar uptake in different treatments. Phosphoproteins were analyzed by two-dimensional gel electrophoresis. Distinct changes in phosphorylation were observed following altered calcium levels. Calcium depletion in root tips with EGTA and A-23187 decreased protein phosphorylation. However, replenishment of calcium following EGTA and ionophore pretreatment enhanced phosphorylation of proteins. Preloading of the root tips with 32P in the presence of EGTA and A-23187 followed by a ten minute calcium treatment, resulted in increased phosphorylation indicating the involvement of calcium, calcium and calmodulin-dependent kinases. Calmodulin antagonist W-7 was effective in inhibiting calcium-promoted phosphorylation. These studies suggest a physiological role for calcium-dependent phosphorylation in calcium-mediated processes in plants.

  5. Concurrent synthesis and release of nod-gene-inducing flavonoids from alfalfa roots

    International Nuclear Information System (INIS)

    Maxwell, C.A.; Phillips, D.A.

    1990-01-01

    Flavonoid signals from alfalfa (Medicago sativa L.) induce transcription of nodulation (nod) genes in Rhizobium meliloti. Alfalfa roots release three major nod-gene inducers: 4',7-dihydroxyflavanone, 4',7-dihydroxyflavone, and 4,4'-dihydroxy-2'-methoxychalcone. The objective of the present study was to define temporal relationships between synthesis and exudation for those flavonoids. Requirements for concurrent flavonoid biosynthesis were assessed by treating roots of intact alfalfa seedlings with [U- 14 C]-L-phenylalanine in the presence or absence of the phenylalanine ammonia-lyase inhibitor L-2-aminoxy-3-phenylpropionic acid (AOPP). In the absence of AOPP, each of the three flavonoids in exudates contained 14 C. In the presence of AOPP, 14 C labeling and release of all the exuded nod-gene inducers were reduced significantly. AOPP inhibited labeling and release of the strongest nod-gene inducer, methoxychalcone, by more than 90%. The release process responsible for exudation of nod-gene inducers appears to be specific rather than a general phenomenon such as a sloughing off of cells during root growth

  6. Characterization of Pearl Millet Root Architecture and Anatomy Reveals Three Types of Lateral Roots

    Science.gov (United States)

    Passot, Sixtine; Gnacko, Fatoumata; Moukouanga, Daniel; Lucas, Mikaël; Guyomarc’h, Soazig; Ortega, Beatriz Moreno; Atkinson, Jonathan A.; Belko, Marème N.; Bennett, Malcolm J.; Gantet, Pascal; Wells, Darren M.; Guédon, Yann; Vigouroux, Yves; Verdeil, Jean-Luc; Muller, Bertrand; Laplaze, Laurent

    2016-01-01

    Pearl millet plays an important role for food security in arid regions of Africa and India. Nevertheless, it is considered an orphan crop as it lags far behind other cereals in terms of genetic improvement efforts. Breeding pearl millet varieties with improved root traits promises to deliver benefits in water and nutrient acquisition. Here, we characterize early pearl millet root system development using several different root phenotyping approaches that include rhizotrons and microCT. We report that early stage pearl millet root system development is characterized by a fast growing primary root that quickly colonizes deeper soil horizons. We also describe root anatomical studies that revealed three distinct types of lateral roots that form on both primary roots and crown roots. Finally, we detected significant variation for two root architectural traits, primary root lenght and lateral root density, in pearl millet inbred lines. This study provides the basis for subsequent genetic experiments to identify loci associated with interesting early root development traits in this important cereal. PMID:27379124

  7. Hypocotyl adventitious root organogenesis differs from lateral root development.

    Science.gov (United States)

    Verstraeten, Inge; Schotte, Sébastien; Geelen, Danny

    2014-01-01

    Wound-induced adventitious root (AR) formation is a requirement for plant survival upon root damage inflicted by pathogen attack, but also during the regeneration of plant stem cuttings for clonal propagation of elite plant varieties. Yet, adventitious rooting also takes place without wounding. This happens for example in etiolated Arabidopsis thaliana hypocotyls, in which AR initiate upon de-etiolation or in tomato seedlings, in which AR initiate upon flooding or high water availability. In the hypocotyl AR originate from a cell layer reminiscent to the pericycle in the primary root (PR) and the initiated AR share histological and developmental characteristics with lateral roots (LRs). In contrast to the PR however, the hypocotyl is a determinate structure with an established final number of cells. This points to differences between the induction of hypocotyl AR and LR on the PR, as the latter grows indeterminately. The induction of AR on the hypocotyl takes place in environmental conditions that differ from those that control LR formation. Hence, AR formation depends on differentially regulated gene products. Similarly to AR induction in stem cuttings, the capacity to induce hypocotyl AR is genotype-dependent and the plant growth regulator auxin is a key regulator controlling the rooting response. The hormones cytokinins, ethylene, jasmonic acid, and strigolactones in general reduce the root-inducing capacity. The involvement of this many regulators indicates that a tight control and fine-tuning of the initiation and emergence of AR exists. Recently, several genetic factors, specific to hypocotyl adventitious rooting in A. thaliana, have been uncovered. These factors reveal a dedicated signaling network that drives AR formation in the Arabidopsis hypocotyl. Here we provide an overview of the environmental and genetic factors controlling hypocotyl-born AR and we summarize how AR formation and the regulating factors of this organogenesis are distinct from LR

  8. Hypocotyl adventitious root organogenesis differs from lateral root development

    Directory of Open Access Journals (Sweden)

    Inge eVerstraeten

    2014-09-01

    Full Text Available Wound-induced adventitious root (AR formation is a requirement for plant survival upon root damage inflicted by pathogen attack, but also during the regeneration of plant stem cuttings for clonal propagation of elite plant varieties. Yet, adventitious rooting also takes place without wounding. This happens for example in etiolated Arabidopsis thaliana hypocotyls, in which AR initiate upon de-etiolation or in tomato seedlings, in which AR initiate upon flooding or high water availability. In the hypocotyl AR originate from a cell layer reminiscent to the pericycle in the primary root (PR and the initiated AR share histological and developmental characteristics with lateral roots (LR. In contrast to the PR however, the hypocotyl is a determinate structure with an established final number of cells. This points to differences between the induction of hypocotyl AR and LR on the PR, as the latter grows indeterminately. The induction of AR on the hypocotyl takes place in environmental conditions that differ from those that control LR formation. Hence, AR formation depends on differentially regulated gene products. Similarly to AR induction in stem cuttings, the capacity to induce hypocotyl AR is genotype-dependent and the plant growth regulator auxin is a key regulator controlling the rooting response. The hormones cytokinins, ethylene, jasmonic acid and strigolactones in general reduce the root-inducing capacity. The involvement of this many regulators indicates that a tight control and fine-tuning of the initiation and emergence of AR exists. Recently, several genetic factors, specific to hypocotyl adventitious rooting in Arabidopsis thaliana, have been uncovered. These factors reveal a dedicated signaling network that drives AR formation in the Arabidopsis hypocotyl. Here we provide an overview of the environmental and genetic factors controlling hypocotyl-born AR and we summarize how AR formation and the regulating factors of this organogenesis are

  9. ROOT I/O in Javascript - Reading ROOT files in a browser

    CERN Multimedia

    CERN. Geneva

    2012-01-01

    A JavaScript version of the ROOT I/O subsystem is being developed, in order to be able to browse (inspect) ROOT files in a platform independent way. This allows the content of ROOT files to be displayed in most web browsers, without having to install ROOT or any other software on the server or on the client. This gives a direct access to ROOT files from new (e.g. portable) devices in a light way. It will be possible to display simple graphical objects such as histograms and graphs (TH1, TH2, TH3, TProfile, TGraph, ...). The rendering will first be done with an external JavaScript graphic library, before investigating a way to produce graphics closer to what ROOT supports on other platforms (X11, Windows).

  10. Saponins isolated from roots of Chlorophytum borivilianum reduce acute and chronic inflammation and histone deacetylase.

    Science.gov (United States)

    Lande, Anirudha A; Ambavade, Shirishkumar D; Swami, Uma S; Adkar, Prafulla P; Ambavade, Prashant D; Waghamare, Arun B

    2015-01-01

    The roots of Chlorophytum borivilanum are used in traditional medicine for the treatment of arthritis and inflammation. The aim of the work was to evaluate the anti-inflammatory activity of isolated saponins from Chlorophytum borivilianum (ISCB). The ISCB was screened using the carrageenan-induced paw edema, histamine-induced paw edema, cotton pellet-induced granuloma, and Freund's adjuvant-induced arthritis in rats at orally administered doses of 3, 10, and 30 mg/kg. Effect of ISCB on histone deacetylase (HDAC) level was measured by the HDAC assay at the highest dose (30 mg/kg). The results showed that the ISCB significantly reduced carrageenan-induced inflammation, histamine-induced inflammation, cotton pellet-induced granuloma and Freund's adjuvant-induced arthritis in rats. The ISCB at a dose of 30 mg/kg significantly inhibited HDAC level in rat paw tissue. It is concluded that saponins isolated from roots of C. borivilianum possess anti-inflammatory and anti-arthritic properties. ISCB may act by inhibiting histamine, prostaglandin and HDAC. This suggests that ISCBs have potential for therapeutic use in the treatment of inflammation and arthritis.

  11. Effect of interleukin-4 on orthodontic tooth movement and associated root resorption.

    Science.gov (United States)

    Hakami, Zaki; Kitaura, Hideki; Kimura, Keisuke; Ishida, Masahiko; Sugisawa, Haruki; Ida, Hiroto; Jafari, Saeed; Takano-Yamamoto, Teruko

    2015-02-01

    Interleukin-4 (IL-4) is a recognized immunomodulatory cytokine that regulates bone homeostasis. However, the influence of IL-4 on orthodontic tooth movement (OTM) and subsequent root resorption is still unknown. Therefore, the purpose of this study was to investigate the effect of IL-4 on tooth movement and its associated root resorption in a mouse model. The maxillary first molars of four male mice for each experimental group were subjected to mesial force by a nickel titanium coil spring for 12 days. Control mice were not given appliances and injections. Varying doses of IL-4 were injected locally, adjacent to the first molar. Two sets of experiments were designed. The first set was composed of three groups: the control, treatment with phosphate-buffered saline (PBS), or 1.5 µg/day of IL-4. The second set was composed of five groups: the control, treatment with 0 (PBS only), 0.015, 0.15, or 1.5 µg/day of IL-4. The distance of OTM was measured and tartrate-resistant acid phosphatase positive cells along the loaded alveolar bone and root surface were identified. The root resorption associated with OTM was evaluated by a scanning electron microscope. The amount of OTM and the number of osteoclasts were significantly decreased in the IL-4-treated mice. Moreover, IL-4 significantly suppressed force-induced odontoclasts and root resorption. IL-4 inhibits tooth movement and prevents root resorption in the mouse model. These results suggest that IL-4 could be used as a useful adjunct to regulate the extent of OTM and also to control root resorption. © The Author 2014. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  12. Anatomic investigation of the lumbosacral nerve roots and dorsal root ganglia by MRI

    International Nuclear Information System (INIS)

    Hasegawa, Toru; Fuse, Kenzo; Mikawa, Yoshihiro; Watanabe, Ryo

    1995-01-01

    The morphology of the lumbosacral nerve roots and dorsal root ganglia (DRG) was examined by using magnetic resonance imaging (MRI) in 11 healthy male volunteers aged 20-40 years. One hundred and twenty-three nerve roots (15 at the L1 level, 22 each at the L2-L5 levels, and 20 at the S1 level) were examined in terms of the position and angle of the bifurcation of the nerve roots, length of the nerve root, and the position and width of DRG. The nerve roots at the lower levels showed more cephalad position and smaller angle of bifurcation on MRI. The distance from the bifurcation of nerve roots to the cephalad edge of DRG was significantly longer in the upper root levels and was significantly shorter in the L5 roots than the S1 roots. The positions of DRG at the S1 level tended to become cephalad. DRG that was positioned toward more caudal direction was larger and more elliptic. MRI provided useful information concerning morphology and anatomical position of nerve roots and DRG, thereby allowing accurate diagnosis and the determination of surgical indications. (N.K.)

  13. Antitoxin activity of Mimosa pudica root extracts against Naja naja and Bangarus caerulus venoms

    Directory of Open Access Journals (Sweden)

    Subramani Meenatchisundaram

    2009-06-01

    Full Text Available Aqueous extract of dried roots of Mimosa pudica was tested for inhibitory activity on lethality, phospholipase activity, edema forming activity, fibrinolytic activity and hemorrhagic activity of Naja naja and Bangarus caerulus venoms. The aqueous extract displayed a significant inhibitory effect on the lethality, phospholipase activity, edema forming activity, fibrinolytic activity and hemorrhagic activity. About 0.14 mg and 0.16 mg of M. pudica extracts were able to completely neutralize the lethal activity of 2LD50 of Naja naja and Bangarus caerulus venoms respectively. The present finding suggests that aqueous extract of M. pudica root possesses compounds, which inhibit the activity of Naja naja and Bangarus caerulus venoms.

  14. Antitoxin activity of Mimosa pudica root extracts against Naja naja and Bangarus caerulus venoms

    Directory of Open Access Journals (Sweden)

    Subramani Meenatchisundaram, Selvin Priyagrace, Ramasamy Vijayaraghavan, Ambikapathi Velmurugan, Govindarajan Parameswari, Antonysamy Michael

    2009-12-01

    Full Text Available Aqueous extract of dried roots of Mimosa pudica was tested for inhibitory activity on lethality, phospholipase activity, edema forming activity, fibrinolytic activity and hemorrhagic activity of Naja naja and Bangarus caerulus venoms. The aqueous extract displayed a significant inhibitory effect on the lethality, phospholipase activity, edema forming activity, fibrinolytic activity and hemorrhagic activity. About 0.14 mg and 0.16 mg of M. pudica extracts were able to completely neutralize the lethal activity of 2LD50 of Naja naja and Bangarus caerulus venoms respectively. The present finding suggests that aqueous extract of M. pudica root possesses compounds, which inhibit the activity of Naja naja and Bangarus caerulus venoms.

  15. Nanobiotechnology approach using plant rooting hormone synthesized silver nanoparticle as “nanobullets” for the dynamic applications in horticulture – An in vitro and ex vitro study

    Directory of Open Access Journals (Sweden)

    Raja Muthuramalingam Thangavelu

    2018-01-01

    Full Text Available Horticulture is the branch of agriculture that deals with science and technology and business of plant cultivation and it is considered to be the foremost part of the world economy. Even though, one of the major challenges which has seriously influenced the economic loss of horticulture is rooting of cuttings and root growth inhibiting plant pathogens. To address this issue through nanobiotechnology, we ingeniously build a concept of silver nanoparticles (AgNPs as “nano-bullets” can act for a dual mode like root enhancer and pathogen destroyer on the target site. After that, we succeeded in AgNPs synthesis, using two auxin rooting hormones of Indole-3-acetic acid and Indole-3-butyric acid as a reducing cum stabilizing agent. Further, its efficacy of root promoting and pathogen inhibitory action was sufficiently validated through in vitro and ex vitro studies with model plants and plant pathogens. As a result, the action duality of hormone-stabilized AgNPs was manifested to threefold enhanced root growth compared to controls and it increased the rooting capabilities against root growth inhibiting phytopathogens. This feature was also proved by the direct antifungal assay. Moreover, hormone-AgNPs left no toxicity to treated plants which was revealed by RAPD molecular markers. Therefore, with a detailed study and analysis with instruments such as Spectroscopy, TEM, Zetasizer, FTIR, Cyclic Voltammetry, Fluorescence microscopy (nanoparticles uptake, SEM coupled with EDS (bioaccumulation, TGA (grafting density and PCR (RAPD analysis, this study can unravel the relevance, scope and current challenges at horticulture plants root development and plant disease management for the sustainable agricultural crop production.

  16. Submergence of Roots for Alveolar Bone Preservation. I. Endodontically Treated Roots.

    Science.gov (United States)

    1977-05-10

    With Endodontic Submerged Roots Scale 0 1 2 3 Periapical 15 0 1 0 Pericoronal 7 3 3 3 (3 cysts ) = 1 _ _ _ _ _ _ _ _ _ = REFERENCES 1. Lam, R.: Contour...with coronal portions of the roots. These epithe lial-lined cysts prevented the formation of osteo- cementum over the coronal surface . In this study...the endodontically treated roots appeared to be primarily a response to the excess root cana l sealer that was expressed coronally and periapically

  17. Influence of temperature and rooting-promoter on the formation of root-primodia and on the rooting of chrysanthemum cuttings under storage

    International Nuclear Information System (INIS)

    Nishio, J.; Fukuda, M.

    1998-01-01

    In order to promote rooting for direct planting cuttings in a lighting cultivation of chrysanthemum, we clarified the effects of light, temperature and term of storage of the cuttings, and analyzed ways of using rooting promoters as a pre-treatment of cuttings for root-primodia formation and rooting. Light as a pre-treatment had little effect, so it seemed to be not necessary for the formation of root primodia. The formation of the root-primodia was most hastened at 25 degrees C; inversely, it was slowed down at low temperatures, that is, the root-primodia were formed in four days at 25 degrees C, five days at 20 degrees C, and seven days at 15 degrees C. With the use of rooting promoters as a pre-treatment for the rooting of cuttings, the root-primodia were formed faster when the whole of cuttings were dipped in 40 mg/L solution of indelebutyric acid (IBA) than when the base of cuttings were dipped or sprayed 400 mg/L solution of IBA. It was appropriate that cuttings were dipped in IBA then put in in plastic-pots (7.5cm) vertically, packed in polyethylene-bags and stored in a corrugated carton box

  18. Resistance to compression of weakened roots subjected to different root reconstruction protocols

    Directory of Open Access Journals (Sweden)

    Lucas Villaça Zogheib

    2011-12-01

    Full Text Available OBJECTIVE: This study evaluated, in vitro, the fracture resistance of human non-vital teeth restored with different reconstruction protocols. MATERIAL AND METHODS: Forty human anterior roots of similar shape and dimensions were assigned to four groups (n=10, according to the root reconstruction protocol: Group I (control: non-weakened roots with glass fiber post; Group II: roots with composite resin by incremental technique and glass fiber post; Group III: roots with accessory glass fiber posts and glass fiber post; and Group IV: roots with anatomic glass fiber post technique. Following post cementation and core reconstruction, the roots were embedded in chemically activated acrylic resin and submitted to fracture resistance testing, with a compressive load at an angle of 45º in relation to the long axis of the root at a speed of 0.5 mm/min until fracture. All data were statistically analyzed with bilateral Dunnett's test (α=0.05. RESULTS: Group I presented higher mean values of fracture resistance when compared with the three experimental groups, which, in turn, presented similar resistance to fracture among each other. None of the techniques of root reconstruction with intraradicular posts improved root strength, and the incremental technique was suggested as being the most recommendable, since the type of fracture that occurred allowed the remaining dental structure to be repaired. CONCLUSION: The results of this in vitro study suggest that the healthy remaining radicular dentin is more important to increase fracture resistance than the root reconstruction protocol.

  19. Living roots effect on 14C-labelled root litter decomposition

    International Nuclear Information System (INIS)

    Billes, G.; Bottner, P.

    1981-01-01

    Wheat was 14 C-labelled by cultivation on soil in pots, from seedling to maturity, in a chamber with constant CO 2 and 14 CO 2 levels. The 14 C-distribution was constant amongst the aerial parts, the roots and the soil in the whole pots. After cutting the plant tops, the pots were dried without disturbing the soil and root system. The pots were then incubated under controlled humidity and temperature conditions for 62 days. In the same time a second wheat cultivation was grown on one half of the pots in normal atmosphere without plant cultivation. The purpose of the work is to study the effect of living roots on decomposition of the former 14 C labelled roots litter. The CO 2 and the 14 CO 2 released from the soil were continuously measured. On incubation days 0, 18, 33 and 62, the remaining litter was separated from soil, and the organic matter was fractionated by repeated hydrolysis and NaOH extraction. Root litter disappeared faster when living roots were present than in bare soil. The accumulation and mineralization rates of humified components in soil followed two stages. While the roots of second wheat cultivation grew actively (until earing), the strong acid hydrolysable components accumulated in larger amount than in the case of bare soil. After earing, while roots activity was depressed, these components were partly mineralized and the 14 CO 2 release was then higher with plants than with bare soil. The humification and mineralization rate were related with living plant phenology stages. (orig.)

  20. The role of radial oxygen loss and root anatomy on zinc uptake and tolerance in mangrove seedlings

    International Nuclear Information System (INIS)

    Cheng, H.; Liu, Y.; Tam, N.F.Y.; Wang, X.; Li, S.Y.; Chen, G.Z.; Ye, Z.H.

    2010-01-01

    Root anatomy, radial oxygen loss (ROL) and zinc (Zn) uptake and tolerance in mangrove plants were investigated using seedlings of Aegiceras corniculatum, Bruguiera gymnorrhiza and Rhizophora stylosa. The results revealed that B. gymnorrhiza, which possessed the 'tightest barrier' in ROL spatial patterns among the three species studied, took up the least Zn and showed the highest Zn tolerance. Furthermore, zinc significantly decreased the ROL of all three plants by inhibition of root permeability, which included an obvious thickening of outer cortex and significant increases of lignification in cell walls. The results of SEM X-ray microanalysis further confirmed that such an inducible, low permeability of roots was likely an adaptive strategy to metal stress by direct prevention of excessive Zn entering into the root. The present study proposes new evidence of structural adaptive strategy on metal tolerance by mangrove seedlings. - Mangrove seedlings with a 'tighter barrier' in ROL spatial pattern exhibit higher Zn tolerance.

  1. The role of radial oxygen loss and root anatomy on zinc uptake and tolerance in mangrove seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, H. [State Key Laboratory for Bio-control, and School of Life Sciences, Sun Yat-sen University, Guangzhou 510006 (China); Liu, Y. [Ministry of Agriculture Key Laboratory of Mariculture Ecology and Products Quality and Safety, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300 (China); Tam, N.F.Y. [Department of Biology and Chemistry, City University of Hong Kong (Hong Kong); Wang, X. [State Key Laboratory for Bio-control, and School of Life Sciences, Sun Yat-sen University, Guangzhou 510006 (China); Li, S.Y.; Chen, G.Z. [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Ye, Z.H., E-mail: lssyzhh@mail.sysu.edu.c [State Key Laboratory for Bio-control, and School of Life Sciences, Sun Yat-sen University, Guangzhou 510006 (China)

    2010-05-15

    Root anatomy, radial oxygen loss (ROL) and zinc (Zn) uptake and tolerance in mangrove plants were investigated using seedlings of Aegiceras corniculatum, Bruguiera gymnorrhiza and Rhizophora stylosa. The results revealed that B. gymnorrhiza, which possessed the 'tightest barrier' in ROL spatial patterns among the three species studied, took up the least Zn and showed the highest Zn tolerance. Furthermore, zinc significantly decreased the ROL of all three plants by inhibition of root permeability, which included an obvious thickening of outer cortex and significant increases of lignification in cell walls. The results of SEM X-ray microanalysis further confirmed that such an inducible, low permeability of roots was likely an adaptive strategy to metal stress by direct prevention of excessive Zn entering into the root. The present study proposes new evidence of structural adaptive strategy on metal tolerance by mangrove seedlings. - Mangrove seedlings with a 'tighter barrier' in ROL spatial pattern exhibit higher Zn tolerance.

  2. Adventitious rooting declines with the vegetative to reproductive switch and involves a changed auxin homeostasis.

    Science.gov (United States)

    Rasmussen, Amanda; Hosseini, Seyed Abdollah; Hajirezaei, Mohammed-Reza; Druege, Uwe; Geelen, Danny

    2015-03-01

    Adventitious rooting, whereby roots form from non-root tissues, is critical to the forestry and horticultural industries that depend on propagating plants from cuttings. A major problem is that age of the tissue affects the ability of the cutting to form adventitious roots. Here, a model system has been developed using Pisum sativum to differentiate between different interpretations of ageing. It is shown that the decline in adventitious rooting is linked to the ontogenetic switch from vegetative to floral and is mainly attributed to the cutting base. Using rms mutants it is demonstrated that the decline is not a result of increased strigolactones inhibiting adventitious root formation. Monitoring endogenous levels of a range of other hormones including a range of cytokinins in the rooting zone revealed that a peak in jasmonic acid is delayed in cuttings from floral plants. Additionally, there is an early peak in indole-3-acetic acid levels 6h post excision in cuttings from vegetative plants, which is absent in cuttings from floral plants. These results were confirmed using DR5:GUS expression. Exogenous supplementation of young cuttings with either jasmonic acid or indole-3-acetic acid promoted adventitious rooting, but neither of these hormones was able to promote adventitious rooting in mature cuttings. DR5:GUS expression was observed to increase in juvenile cuttings with increasing auxin treatment but not in the mature cuttings. Therefore, it seems the vegetative to floral ontogenetic switch involves an alteration in the tissue's auxin homeostasis that significantly reduces the indole-3-acetic acid pool and ultimately results in a decline in adventitious root formation. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  3. Cadmium induces hypodermal periderm formation in the roots of the monocotyledonous medicinal plant Merwilla plumbea.

    Science.gov (United States)

    Lux, Alexander; Vaculík, Marek; Martinka, Michal; Lisková, Desana; Kulkarni, Manoj G; Stirk, Wendy A; Van Staden, Johannes

    2011-02-01

    Merwilla plumbea is an important African medicinal plant. As the plants grow in soils contaminated with metals from mining activities, the danger of human intoxication exists. An experiment with plants exposed to cadmium (Cd) was performed to investigate the response of M. plumbea to this heavy metal, its uptake and translocation to plant organs and reaction of root tissues. Plants grown from seeds were cultivated in controlled conditions. Hydroponic cultivation is not suitable for this species as roots do not tolerate aquatic conditions, and additional stress by Cd treatment results in total root growth inhibition and death. After cultivation in perlite the plants exposed to 1 and 5 mg Cd L(-1) in half-strength Hoagland's solution were compared with control plants. Growth parameters were evaluated, Cd content was determined by inductively coupled plasma mass spectroscopy (ICP-MS) and root structure was investigated using various staining procedures, including the fluorescent stain Fluorol yellow 088 to detect suberin deposition in cell walls. The plants exposed to Cd were significantly reduced in growth. Most of the Cd taken up by plants after 4 weeks cultivation was retained in roots, and only a small amount was translocated to bulbs and leaves. In reaction to higher Cd concentrations, roots developed a hypodermal periderm close to the root tip. Cells produced by cork cambium impregnate their cell walls by suberin. It is suggested that the hypodermal periderm is developed in young root parts in reaction to Cd toxicity to protect the root from radial uptake of Cd ions. Secondary meristems are usually not present in monocotyledonous species. Another interpretation explaining formation of protective suberized layers as a result of periclinal divisions of the hypodermis is discussed. This process may represent an as yet unknown defence reaction of roots when exposed to elemental stress.

  4. The grapevine root-specific aquaporin VvPIP2;4N controls root hydraulic conductance and leaf gas exchange under well-watered conditions but not under water stress.

    Science.gov (United States)

    Perrone, Irene; Gambino, Giorgio; Chitarra, Walter; Vitali, Marco; Pagliarani, Chiara; Riccomagno, Nadia; Balestrini, Raffaella; Kaldenhoff, Ralf; Uehlein, Norbert; Gribaudo, Ivana; Schubert, Andrea; Lovisolo, Claudio

    2012-10-01

    We functionally characterized the grape (Vitis vinifera) VvPIP2;4N (for Plasma membrane Intrinsic Protein) aquaporin gene. Expression of VvPIP2;4N in Xenopus laevis oocytes increased their swelling rate 54-fold. Northern blot and quantitative reverse transcription-polymerase chain reaction analyses showed that VvPIP2;4N is the most expressed PIP2 gene in root. In situ hybridization confirmed root localization in the cortical parenchyma and close to the endodermis. We then constitutively overexpressed VvPIP2;4N in grape 'Brachetto', and in the resulting transgenic plants we analyzed (1) the expression of endogenous and transgenic VvPIP2;4N and of four other aquaporins, (2) whole-plant, root, and leaf ecophysiological parameters, and (3) leaf abscisic acid content. Expression of transgenic VvPIP2;4N inhibited neither the expression of the endogenous gene nor that of other PIP aquaporins in both root and leaf. Under well-watered conditions, transgenic plants showed higher stomatal conductance, gas exchange, and shoot growth. The expression level of VvPIP2;4N (endogenous + transgene) was inversely correlated to root hydraulic resistance. The leaf component of total plant hydraulic resistance was low and unaffected by overexpression of VvPIP2;4N. Upon water stress, the overexpression of VvPIP2;4N induced a surge in leaf abscisic acid content and a decrease in stomatal conductance and leaf gas exchange. Our results show that aquaporin-mediated modifications of root hydraulics play a substantial role in the regulation of water flow in well-watered grapevine plants, while they have a minor role upon drought, probably because other signals, such as abscisic acid, take over the control of water flow.

  5. Protective effect of bioactivity guided fractions of Ziziphus jujuba Mill. root bark against hepatic injury and chronic inflammation via inhibiting inflammatory markers and oxidative stress

    Directory of Open Access Journals (Sweden)

    Raghuram Kandimalla

    2016-09-01

    Full Text Available The tribal communities of North Eastern India rely on herbal medicine to cure various disease conditions. Ziziphus jujuba Mill. (Rhamnaceae is one of such medicinal plants used for curing liver ailments, insomnia, anemia, diarrhea, diabetic complications, cancer and loss of appetite. The present study was aimed to describe the protective ability of Z. jujuba root bark against hepatic injury and chronic inflammation. Bioactivity guided fractionation of Z. jujuba methanol extract (ZJME was performed using different solvents of increasing polarity viz. hexane (ZJHF, chloroform (ZJCF, ethyl acetate (ZJEAF, water (ZJWF and residue (ZJMR. In vitro antioxidant results revealed that both ZJME and ZJWF possess strong antioxidant activity among all the fractions and mother extract tested. Further, ZJME and ZJWF showed significant protection against CCl4 intoxicated HepG2 cell lines by means of increased cell viability and decreased LDH levels compared to control group. ZJME at 200, 400 mg/kg and ZJWF at 50, 100 mg/kg inhibited the lipid peroxidation and significantly restored the liver function markers (AST, ALT, ALP, LDH, SOD and CAT and cytokine levels (TNF-α, Il-1β and Il-10 in CCl4 induced acute liver damage in rats. All the results were comparable with standard drug silymarin which was further confirmed by histopathology analysis of liver. Similarly, inflammation and increase inflammatory cytokines levels of carrageenan induced paw edema in rats have been refurbished to normal levels on par with the standard drug indomethacin. ZJWF demonstrated potent response than ZJME in all the biological tests conducted. The results of the study signify the ability of Z. jujuba root bark as good therapeutic agent for liver toxicity and chronic inflammation.

  6. Root resorption

    DEFF Research Database (Denmark)

    Kjaer, Inger

    2014-01-01

    Introduction: This paper summarizes the different conditions, which have a well-known influence on the resorption of tooth roots, exemplified by trauma and orthodontic treatment. The concept of the paper is to summarize and explain symptoms and signs of importance for avoiding resorption during...... orthodontic treatment. The Hypothesis: The hypothesis in this paper is that three different tissue layers covering the root in the so-called periroot sheet can explain signs and symptoms of importance for avoiding root resorption during orthodontic treatment. These different tissue layers are; outermost...... processes provoked by trauma and orthodontic pressure. Inflammatory reactions are followed by resorptive processes in the periroot sheet and along the root surface. Evaluation of the Hypothesis: Different morphologies in the dentition are signs of abnormal epithelium or an abnormal mesodermal layer. It has...

  7. [Cell surface peroxidase--generator of superoxide anion in wheat root cells under wound stress].

    Science.gov (United States)

    Chasov, A V; Gordon, L Kh; Kolesnikov, O P; Minibaeva, F V

    2002-01-01

    Development of wound stress in excised wheat roots is known to be accompanied with an increase in reactive oxygen species (ROS) production, fall of membrane potential, release of K+ from cells, alkalization of extracellular solution, changes in respiration and metabolism of structural lipids. Dynamics of superoxide release correlates with changes in other physiological parameters, indicating the cross-reaction of these processes. Activity of peroxidase in extracellular solution after a 1 h incubation and removal of roots was shown to be stimulated by the range of organic acids, detergents, metals, and to be inhibited by cyanide. Superoxide production was sensitive to the addition of Mn2+ and H2O2. Increase in superoxide production correlates with the enhancement of peroxidase activity at the application of organic acids and detergents. The results obtained indicate that cell surface peroxidase is one of the main generators of superoxide in wounded wheat root cells. Different ways of stimulation of the ROS producing activity in root cells is supposed. By controlling superoxide and hydrogen peroxide formation, the cell surface peroxidase can control the adaptation processes in stressed plant cells.

  8. Measuring and Modeling Root Distribution and Root Reinforcement in Forested Slopes for Slope Stability Calculations

    Science.gov (United States)

    Cohen, D.; Giadrossich, F.; Schwarz, M.; Vergani, C.

    2016-12-01

    Roots provide mechanical anchorage and reinforcement of soils on slopes. Roots also modify soil hydrological properties (soil moisture content, pore-water pressure, preferential flow paths) via subsurface flow path associated with root architecture, root density, and root-size distribution. Interactions of root-soil mechanical and hydrological processes are an important control of shallow landslide initiation during rainfall events and slope stability. Knowledge of root-distribution and root strength are key components to estimate slope stability in vegetated slopes and for the management of protection forest in steep mountainous area. We present data that show the importance of measuring root strength directly in the field and present methods for these measurements. These data indicate that the tensile force mobilized in roots depends on root elongation (a function of soil displacement), root size, and on whether roots break in tension of slip out of the soil. Measurements indicate that large lateral roots that cross tension cracks at the scarp are important for slope stability calculations owing to their large tensional resistance. These roots are often overlooked and when included, their strength is overestimated because extrapolated from measurements on small roots. We present planned field experiments that will measure directly the force held by roots of different sizes during the triggering of a shallow landslide by rainfall. These field data are then used in a model of root reinforcement based on fiber-bundle concepts that span different spacial scales, from a single root to the stand scale, and different time scales, from timber harvest to root decay. This model computes the strength of root bundles in tension and in compression and their effect on soil strength. Up-scaled to the stand the model yields the distribution of root reinforcement as a function of tree density, distance from tree, tree species and age with the objective of providing quantitative

  9. Physiological aspects of fungi isolated from root nodules of faba bean (Vicia faba L.).

    Science.gov (United States)

    Omar, S A; Abd-Alla, M H

    2000-03-01

    The present study was made to isolate and assess some physiological characteristics of root nodule-colonizing fungi. During this study, 17 fungal species were isolated from root nodule samples taken from faba bean plants (Vicia faba L.) collected from different sites at Assiut area (Egypt). The growth of faba bean plants in pots was significantly promoted by soil inoculation with most fungi. Growth was checked in pots with inocula of Cladosporium cladosporioides, Fusarium moniliforme, F: oxysporium, F solani, Macrophominia phaseolina and Rhizoctonia solani which were added separately. All growth-promoting fungi were capable of producing cellulase, pectin lyase, polygalacturonase, protease, urease, amidase, acid phosphatase, alkaline phosphatase and arylsulfatase in growth medium supplemented with the corresponding substrates. Four fungal species, Aspergillus awamori, A. flavus, Penicillium chrysogenum and Trichoderma koningii showed the highest rates of enzyme formation. The effect of the addition of six trace elements to the growth media at 30 micromol/ml on enzyme production revealed some dependency on species, enzyme and metal ion. Cd2+, Hg2+ and Zn2+ generally inhibited enzyme activity. Cu(1+), Fe3+ and Al3+ showed a stimulatory effect. Fungicides (afugan and tilt) and herbicides (brominal and fusilade) at 50 ppm generally promoted enzyme activity, but insecticides (kelthane and fenvalerate) caused some inhibition to enzyme activities. Salinization of the growth media with NaCl strongly inhibited the enzymatic activity of all fungi at concentrations between 0.5 and 1.5%.

  10. Rooting depth and root depth distribution of Trifolium repens × T. uniflorum interspecific hybrids.

    Science.gov (United States)

    Nichols, S N; Hofmann, R W; Williams, W M; van Koten, C

    2016-05-20

    Traits related to root depth distribution were examined in Trifolium repens × T. uniflorum backcross 1 (BC 1 ) hybrids to determine whether root characteristics of white clover could be improved by interspecific hybridization. Two white clover cultivars, two T. uniflorum accessions and two BC 1 populations were grown in 1 -m deep tubes of sand culture. Maximum rooting depth and root mass distribution were measured at four harvests over time, and root distribution data were fitted with a regression model to provide measures of root system shape. Morphological traits were measured at two depths at harvest 3. Root system shape of the hybrids was more similar to T. uniflorum than to white clover. The hybrids and T. uniflorum had a higher rate of decrease in root mass with depth than white clover, which would result in higher proportions of root mass in the upper profile. Percentage total root mass at 100-200 mm depth was higher for T. uniflorum than white clover, and for Crusader BC 1 than 'Crusader'. Roots of the hybrids and T. uniflorum also penetrated deeper than those of white clover. T. uniflorum had thicker roots at 50-100 mm deep than the other entries, and more of its fine root mass at 400-500 mm. The hybrids and white clover had more of their fine root mass higher in the profile. Consequently, T. uniflorum had a higher root length density at 400-500 mm than most entries, and a smaller decrease in root length density with depth. These results demonstrate that rooting characteristics of white clover can be altered by hybridization with T. uniflorum, potentially improving water and nutrient acquisition and drought resistance. Root traits of T. uniflorum are likely to be adaptations to soil moisture and fertility in its natural environment. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Reduction of mouse atherosclerosis by urokinase inhibition or with a limited-spectrum matrix metalloproteinase inhibitor

    DEFF Research Database (Denmark)

    Hu, Jie Hong; Touch, Phanith; Zhang, Jingwan

    2015-01-01

    -accelerated atherosclerosis) to investigate whether systemic inhibition of proteolytic activity of uPA or a subset of MMPs can reduce protease-induced atherosclerosis and aortic dilation. METHODS AND RESULTS: SR-uPA mice were fed a high-fat diet for 10 weeks and treated either with an antibody inhibiting mouse uPA (mU1...... surface lesion coverage. Several lines of evidence identified MMP-13 as a mediator of uPA-induced aortic MMP activity. CONCLUSIONS: Pharmacological inhibition of either uPA or selected MMPs decreased atherosclerosis in SR-uPA mice. uPA inhibition decreased aortic dilation. Differential effects of both...... agents on aortic root vs. distal aortic atherosclerosis suggest prevention of atherosclerosis progression vs. initiation. Systemic inhibition of uPA or a subset of MMPs shows promise for treating atherosclerosis....

  12. Higher concentrations of nanoscale zero-valent iron (nZVI) in soil induced rice chlorosis due to inhibited active iron transportation

    International Nuclear Information System (INIS)

    Wang, Jie; Fang, Zhanqiang; Cheng, Wen; Yan, Xiaomin; Tsang, Pokeung Eric; Zhao, Dongye

    2016-01-01

    In this study, the effects of concentrations 0, 100, 250, 500, 750 and 1000 mg kg"−"1 of nanoscale zero-valent iron (nZVI) on germination, seedlings growth, physiology and toxicity mechanisms were investigated. The results showed that nZVI had no effect on germination, but inhibited the rice seedlings growth in higher concentrations (>500 mg kg"−"1 nZVI). The highest suppression rate of the length of roots and shoots reached 46.9% and 57.5%, respectively. The 1000mg kg"−"1 nZVI caused the highest suppression rates for chlorophyll and carotenoids, at 91.6% and 85.2%, respectively. In addition, the activity of antioxidant enzymes was altered by the translocation of nanoparticles and changes in active iron content. Visible symptoms of iron deficiency were observed at higher concentrations, at which the active iron content decreased 61.02% in the shoots, but the active iron content not decreased in roots. Interestingly, the total and available amounts of iron in the soil were not less than those in the control. Therefore, the plants iron deficiency was not caused by (i) deficiency of available iron in the soil and (ii) restraint of the absorption that plant takes in the available iron, while induced by (ⅲ) the transport of active iron from the root to the shoot was blocked. The cortex tissues were seriously damaged by nZVI which was transported from soil to the root, these were proved by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). This current study shows that the mechanism of iron deficiency in rice seedling was due to transport of active iron from the root to the shoot blocked, which was caused by the uptake of nZVI. - Highlights: • Higher concentrations of nZVI induced iron deficiency in rice seedlings visibly. • nZVI was taken in rice seedlings and transported form root to shoot. • The pathway of active iron transport from root to shoot was inhibited. • The cortex tissues

  13. Root form and clinical radiographic estimation of the number of root ...

    African Journals Online (AJOL)

    The root form of 100 extracted maxillary premolars, the pre-operative radiographic estimation and clinical radiographic determination of the number of root canals in 340 maxillary premolars of Nigerian patients attending the dental hospital for endodontic treatment were studied. The maxillary second premolars had one root ...

  14. Abscisic Acid Regulates Auxin Homeostasis in Rice Root Tips to Promote Root Hair Elongation

    Directory of Open Access Journals (Sweden)

    Tao Wang

    2017-06-01

    Full Text Available Abscisic acid (ABA plays an essential role in root hair elongation in plants, but the regulatory mechanism remains to be elucidated. In this study, we found that exogenous ABA can promote rice root hair elongation. Transgenic rice overexpressing SAPK10 (Stress/ABA-activated protein kinase 10 had longer root hairs; rice plants overexpressing OsABIL2 (OsABI-Like 2 had attenuated ABA signaling and shorter root hairs, suggesting that the effect of ABA on root hair elongation depends on the conserved PYR/PP2C/SnRK2 ABA signaling module. Treatment of the DR5-GUS and OsPIN-GUS lines with ABA and an auxin efflux inhibitor showed that ABA-induced root hair elongation depends on polar auxin transport. To examine the transcriptional response to ABA, we divided rice root tips into three regions: short root hair, long root hair and root tip zones; and conducted RNA-seq analysis with or without ABA treatment. Examination of genes involved in auxin transport, biosynthesis and metabolism indicated that ABA promotes auxin biosynthesis and polar auxin transport in the root tip, which may lead to auxin accumulation in the long root hair zone. Our findings shed light on how ABA regulates root hair elongation through crosstalk with auxin biosynthesis and transport to orchestrate plant development.

  15. The inhibiting effects of components of stinging nettle roots on experimentally induced prostatic hyperplasia in mice.

    Science.gov (United States)

    Lichius, J J; Renneberg, H; Blaschek, W; Aumüller, G; Muth, C

    1999-10-01

    Direct implanting of fetal urogenital sinus (UGS) tissue into the ventral prostate gland of adult mice led to a 4-fold weight increase of the manipulated prostatic lobe. The induced growth could be reduced by the polysaccharide fraction (POLY-M) of the 20% methanolic extract of stinging nettle roots by 33.8%.

  16. [Effects nutrients on the seedlings root hair development and root growth of Poncirus trifoliata under hydroponics condition].

    Science.gov (United States)

    Cao, Xiu; Xia, Ren-Xue; Zhang, De-Jian; Shu, Bo

    2013-06-01

    Ahydroponics experiment was conducted to study the effects of nutrients (N, P, K, Ca, Mg, Fe, and Mn) deficiency on the length of primary root, the number of lateral roots, and the root hair density, length, and diameter on the primary root and lateral roots of Poncirus trifoliata seedlings. Under the deficiency of each test nutrient, root hair could generate, but was mainly concentrated on the root base and fewer on the root tip. The root hair density on lateral roots was significantly larger than that on primary root, but the root hair length was in adverse. The deficiency of each test nutrient had greater effects on the growth and development of root hairs, with the root hair density on primary root varied from 55.0 to 174.3 mm(-2). As compared with the control, Ca deficiency induced the significant increase of root hair density and length on primary root, P deficiency promoted the root hair density and length on the base and middle part of primary root and on the lateral roots significantly, Fe deficiency increased the root hair density but decreased the root hair length on the tip of primary root significantly, K deficiency significantly decreased the root hair density, length, and diameter on primary root and lateral roots, whereas Mg deficiency increased the root hair length of primary root significantly. In all treatments of nutrient deficiency, the primary root had the similar growth rate, but, with the exceptions of N and Mg deficiency, the lateral roots exhibited shedding and regeneration.

  17. Root fractures

    DEFF Research Database (Denmark)

    Andreasen, Jens Ove; Christensen, Søren Steno Ahrensburg; Tsilingaridis, Georgios

    2012-01-01

    The purpose of this study was to analyze tooth loss after root fractures and to assess the influence of the type of healing and the location of the root fracture. Furthermore, the actual cause of tooth loss was analyzed....

  18. GiA Roots: software for the high throughput analysis of plant root system architecture

    Science.gov (United States)

    2012-01-01

    Background Characterizing root system architecture (RSA) is essential to understanding the development and function of vascular plants. Identifying RSA-associated genes also represents an underexplored opportunity for crop improvement. Software tools are needed to accelerate the pace at which quantitative traits of RSA are estimated from images of root networks. Results We have developed GiA Roots (General Image Analysis of Roots), a semi-automated software tool designed specifically for the high-throughput analysis of root system images. GiA Roots includes user-assisted algorithms to distinguish root from background and a fully automated pipeline that extracts dozens of root system phenotypes. Quantitative information on each phenotype, along with intermediate steps for full reproducibility, is returned to the end-user for downstream analysis. GiA Roots has a GUI front end and a command-line interface for interweaving the software into large-scale workflows. GiA Roots can also be extended to estimate novel phenotypes specified by the end-user. Conclusions We demonstrate the use of GiA Roots on a set of 2393 images of rice roots representing 12 genotypes from the species Oryza sativa. We validate trait measurements against prior analyses of this image set that demonstrated that RSA traits are likely heritable and associated with genotypic differences. Moreover, we demonstrate that GiA Roots is extensible and an end-user can add functionality so that GiA Roots can estimate novel RSA traits. In summary, we show that the software can function as an efficient tool as part of a workflow to move from large numbers of root images to downstream analysis. PMID:22834569

  19. Embryonic origin of the Arabidopsis primary root and root meristem initials

    NARCIS (Netherlands)

    Scheres, B.J.G.; Wolkenfelt, H.; Willemsen, V.; Terlouw, M.; Lawson, E.; Dean, C.; Weisbeek, P.

    1994-01-01

    The embryonic origin of the Arabidopsis root and hypocotyl region has been investigated using histological techniques and clonal analysis. Our data reveal the pattern of cell division in the embryo giving rise to the various initials within the root promeristem. A small region of the root at its

  20. In vitro antimicrobial activity of root canal sealers and calcium hydroxide paste

    Directory of Open Access Journals (Sweden)

    Alessandro L Cavalcanti

    2010-01-01

    Full Text Available Aim: To evaluate the in vitro antimicrobial activity of different root canal sealers and calcium hydroxide (CH paste. Materials and Methods: The sample was composed of two sealers (Fill Canal® and Sealer 26® , one CH cement (Hydro C® , and a CH paste. The agar diffusion test was performed in Petri dishes inoculated with the following microorganisms: Streptococcus salivarius, Streptococcus oralis, Streptococcus mitis, Lactobacillus casei, Streptococcus mutans, Candida albicans, Candida krusei, and Candida tropicalis. The diameters of the zones of microbial growth inhibition were measured after 24 h. The tests were performed in triplicate. Data were analyzed statistically by ANOVA and Tukey′s test at 5% significance level. Results: Fill Canal® exhibited the largest mean zone of microbial growth inhibition against the Candida species and differed significantly from the other groups (P < 0.001. When inhibition was observed against S. mitis and S. oralis, the CH paste presented a larger mean zone of microbial growth inhibition than those of the other materials (P < 0.05. Regarding the inhibition of S. mutans, a statistically significant difference was observed only between the CH paste and Hydro C® (P < 0.05; the paste produced the largest mean zone of microbial growth inhibition against this microorganism. Regarding the inhibition of S. salivarius, Fill Canal® presented smaller mean zone of microbial growth inhibition than Sealer 26® and CH paste (P < 0.05. Conclusion: All the materials presented zones of microbial growth inhibition against all the test bacteria. Fill Canal® presented the largest mean zone of inhibition against the Candida species. For the Streptococcus cultures, none of the sealers presented inhibition superior to that of the CH paste.

  1. MAIL1 is essential for development of the primary root but not of anchor roots.

    Science.gov (United States)

    Ühlken, Christine; Hoth, Stefan; Weingartner, Magdalena

    2014-01-01

    MAIN-LIKE1 (MAIL1) is a ubiquitously expressed nuclear protein, which has a crucial function during root development. We have recently described loss of function mutants for MAIL1, in which the organization and function of the primary root meristem is lost soon after germination. Moreover cell differentiation is impaired resulting in primary root growth arrest soon after emergence. Here we show that mail1 mutants form several anchor roots from the hypocotyl to root junction. These anchor roots show similar defects in the organization of the stem cell niche as the primary root. In contrast, differentiation processes are not impaired and thus anchor roots seem to be able to compensate for the loss of primary root function. Our data show that MAIL1 is essential for specification of cell fate in the primary root but not in anchor roots.

  2. computer-aided root aided root aided root aided root-locus

    African Journals Online (AJOL)

    User

    m, stability, transient response, root-locus, iteration he means by which any a machine, mechanism or d or altered in accordance. Introduction of feedback has the advantages of f system performance to in system parameters, ponse and minimizing the ignals. However, feedback of components, increases ain and introduces ...

  3. Why rooting fails

    OpenAIRE

    Creutz, Michael

    2007-01-01

    I explore the origins of the unphysical predictions from rooted staggered fermion algorithms. Before rooting, the exact chiral symmetry of staggered fermions is a flavored symmetry among the four "tastes." The rooting procedure averages over tastes of different chiralities. This averaging forbids the appearance of the correct 't Hooft vertex for the target theory.

  4. Root system markup language: toward a unified root architecture description language.

    Science.gov (United States)

    Lobet, Guillaume; Pound, Michael P; Diener, Julien; Pradal, Christophe; Draye, Xavier; Godin, Christophe; Javaux, Mathieu; Leitner, Daniel; Meunier, Félicien; Nacry, Philippe; Pridmore, Tony P; Schnepf, Andrea

    2015-03-01

    The number of image analysis tools supporting the extraction of architectural features of root systems has increased in recent years. These tools offer a handy set of complementary facilities, yet it is widely accepted that none of these software tools is able to extract in an efficient way the growing array of static and dynamic features for different types of images and species. We describe the Root System Markup Language (RSML), which has been designed to overcome two major challenges: (1) to enable portability of root architecture data between different software tools in an easy and interoperable manner, allowing seamless collaborative work; and (2) to provide a standard format upon which to base central repositories that will soon arise following the expanding worldwide root phenotyping effort. RSML follows the XML standard to store two- or three-dimensional image metadata, plant and root properties and geometries, continuous functions along individual root paths, and a suite of annotations at the image, plant, or root scale at one or several time points. Plant ontologies are used to describe botanical entities that are relevant at the scale of root system architecture. An XML schema describes the features and constraints of RSML, and open-source packages have been developed in several languages (R, Excel, Java, Python, and C#) to enable researchers to integrate RSML files into popular research workflow. © 2015 American Society of Plant Biologists. All Rights Reserved.

  5. Anti-Allergic Activity of a Platycodon Root Ethanol Extract

    Directory of Open Access Journals (Sweden)

    Dong-Yeul Kwon

    2010-07-01

    Full Text Available Platycodon grandiflorum (Campanulaceae is used as traditional medicine in Asian countries. In Korean traditional medicine, Platycodon root has been widely used since ancient times as a traditional drug to treat cold, cough and asthma. However, its effects on bone marrow-derived mast cell (BMMC-mediated allergy and inflammation mechanisms remain unknown. In this study, the biological effect of Platycodon root ethanol extract (PE was evaluated in BMMC after induction of allergic mediators by phorbol 12-myristate 13-acetate (PMA plus calcium ionophore A23187 (A23187 stimulation. The effect of PE on the production of several allergic mediators, such as interleukin-6 (IL-6, prostaglandin D2 (PGD2, leukotriene C4 (LTC4, β-Hexosaminidase (β-Hex and cyclooxygenase-2 (COX-2 protein, was investigated. The results demonstrate that PE inhibits PMA + A23187 induced production of IL-6, PGD2, LTC4, β-Hexosaminidase and COX-2 protein. Taken together, these results indicate that PE has the potential for use in the treatment of allergy.

  6. Trans-specific gene silencing of acetyl-CoA carboxylase in a root-parasitic plant.

    Science.gov (United States)

    Bandaranayake, Pradeepa C G; Yoder, John I

    2013-05-01

    Parasitic species of the family Orobanchaceae are devastating agricultural pests in many parts of the world. The control of weedy Orobanchaceae spp. is challenging, particularly due to the highly coordinated life cycles of the parasite and host plants. Although host genetic resistance often provides the foundation of plant pathogen management, few genes that confer resistance to root parasites have been identified and incorporated into crop species. Members of the family Orobanchaceae acquire water, nutrients, macromolecules, and oligonucleotides from host plants through haustoria that connect parasite and host plant roots. We are evaluating a resistance strategy based on using interfering RNA (RNAi) that is made in the host but inhibitory in the parasite as a parasite-derived oligonucleotide toxin. Sequences from the cytosolic acetyl-CoA carboxylase (ACCase) gene from Triphysaria versicolor were cloned in hairpin conformation and introduced into Medicago truncatula roots by Agrobacterium rhizogenes transformation. Transgenic roots were recovered for four of five ACCase constructions and infected with T. versicolor against parasitic weeds. In all cases, Triphysaria root viability was reduced up to 80% when parasitizing a host root bearing the hairpin ACCase. Triphysaria root growth was recovered by exogenous application of malonate. Reverse-transcriptase polymerase chain reaction (RT-PCR) showed that ACCase transcript levels were dramatically decreased in Triphysaria spp. parasitizing transgenic Medicago roots. Northern blot analysis identified a 21-nucleotide, ACCase-specific RNA in transgenic M. truncatula and in T. versicolor attached to them. One hairpin ACCase construction was lethal to Medicago spp. unless grown in media supplemented with malonate. Quantitative RT-PCR showed that the Medicago ACCase was inhibited by the Triphysaria ACCase RNAi. This work shows that ACCase is an effective target for inactivation in parasitic plants by trans-specific gene

  7. Shakuyakukanzoto attenuates oxaliplatin-induced cold dysesthesia by inhibiting the expression of transient receptor potential melastatin 8 in mice

    Directory of Open Access Journals (Sweden)

    Tsugunobu Andoh

    2017-01-01

    Full Text Available Oxaliplatin-induced peripheral neuropathy characterized especially as cold dysesthesia is a major dose-limiting side effect of the drug and is very difficult to control. In the present study, we examined whether the traditional herbal formulation Shakuyakukanzoto (SKT: 芍藥甘草湯Sháo Yào Gān Cǎo Tāng could relieve oxaliplatin-induced cold dysesthesia in mice. The inhibitory mechanisms were also investigated. Repetitive administration of SKT (0.1–1.0 g/kg starting from the day after oxaliplatin injection inhibited cold dysesthesia in a dose-dependent manner. Our previous report has shown that the mRNA expression of transient receptor potential melastatin 8 (TRPM8, characterized as a cold-sensing cation channel, is increased in the dorsal root ganglia of mice treated with oxaliplatin. In addition, TRPM8 antagonist TC-I 2014 (10 and 30 mg/kg also attenuated cold dysesthesia in oxaliplatin-treated mice. Taken together, it is suggested that TRPM8 is involved in the cold dysesthesia induced by oxaliplatin. Repetitive administration of SKT inhibited the mRNA expression of TRPM8 induced by oxaliplatin in the dorsal root ganglia. These results suggested that prophylactic repetitive administration of SKT is effective in preventing the exacerbation of oxaliplatin-induced cold dysesthesia by inhibiting the mRNA expression of TRPM8 in the dorsal root ganglia.

  8. Characterization of Root and Shoot Traits in Wheat Cultivars with Putative Differences in Root System Size

    Directory of Open Access Journals (Sweden)

    Victoria Figueroa-Bustos

    2018-07-01

    Full Text Available Root system size is a key trait for improving water and nitrogen uptake efficiency in wheat (Triticum aestivum L.. This study aimed (i to characterize the root system and shoot traits of five wheat cultivars with apparent differences in root system size; (ii to evaluate whether the apparent differences in root system size observed at early vegetative stages in a previous semi-hydroponic phenotyping experiment are reflected at later phenological stages in plants grown in soil using large rhizoboxes. The five wheat cultivars were grown in a glasshouse in rhizoboxes filled to 1.0 m with field soil. Phenology and shoot traits were measured and root growth and proliferation were mapped to quantify root length density (RLD, root length per plant, root biomass and specific root length (SRL. Wheat cultivars with large root systems had greater root length, more root biomass and thicker roots, particularly in the top 40 cm, than those with small root systems. Cultivars that reached anthesis later had larger root system sizes than those that reached anthesis earlier. Later anthesis allowed more time for root growth and proliferation. Cultivars with large root systems had 25% more leaf area and biomass than those with small root systems, which presumably reflects high canopy photosynthesis to supply the demand for carbon assimilates to roots. Wheat cultivars with contrasting root system sizes at the onset of tillering (Z2.1 in a semi-hydroponic phenotyping system maintained their size ranking at booting (Z4.5 when grown in soil. Phenology, particularly time to anthesis, was associated with root system size.

  9. Effect of citric acid, tetracycline, and doxycycline on instrumented periodontally involved root surfaces: A SEM study

    Directory of Open Access Journals (Sweden)

    Gurparkash Singh Chahal

    2014-01-01

    Full Text Available Background: A surface smear layer consisting of organic and inorganic material is formed on the root surface following mechanical instrumentation and may inhibit the formation of new connective tissue attachment to the root surface. Modification of the tooth surface by root conditioning has resulted in improved connective tissue attachment and has advanced the goal of reconstructive periodontal treatment. Aim: The aim of this study was to compare the effects of citric acid, tetracycline, and doxycycline on the instrumented periodontally involved root surfaces in vitro using a scanning electron microscope. Settings and Design: A total of 45 dentin samples obtained from 15 extracted, scaled, and root planed teeth were divided into three groups. Materials and Methods: The root conditioning agents were applied with cotton pellets using the "Passive burnishing technique" for 5 minutes. The samples were then examined by the scanning electron microscope. Statistical Analysis Used: The statistical analysis was carried out using Statistical Package for Social Sciences (SPSS Inc., Chicago, IL, version 15.0 for Windows. For all quantitative variables means and standard deviations were calculated and compared. For more than two groups ANOVA was applied. For multiple comparisons post hoc tests with Bonferroni correction was used. Results: Upon statistical analysis the root conditioning agents used in this study were found to be effective in removing the smear layer, uncovering and widening the dentin tubules and unmasking the dentin collagen matrix. Conclusion: Tetracycline HCl was found to be the best root conditioner among the three agents used.

  10. Control of root system architecture by DEEPER ROOTING 1 increases rice yield under drought conditions.

    Science.gov (United States)

    Uga, Yusaku; Sugimoto, Kazuhiko; Ogawa, Satoshi; Rane, Jagadish; Ishitani, Manabu; Hara, Naho; Kitomi, Yuka; Inukai, Yoshiaki; Ono, Kazuko; Kanno, Noriko; Inoue, Haruhiko; Takehisa, Hinako; Motoyama, Ritsuko; Nagamura, Yoshiaki; Wu, Jianzhong; Matsumoto, Takashi; Takai, Toshiyuki; Okuno, Kazutoshi; Yano, Masahiro

    2013-09-01

    The genetic improvement of drought resistance is essential for stable and adequate crop production in drought-prone areas. Here we demonstrate that alteration of root system architecture improves drought avoidance through the cloning and characterization of DEEPER ROOTING 1 (DRO1), a rice quantitative trait locus controlling root growth angle. DRO1 is negatively regulated by auxin and is involved in cell elongation in the root tip that causes asymmetric root growth and downward bending of the root in response to gravity. Higher expression of DRO1 increases the root growth angle, whereby roots grow in a more downward direction. Introducing DRO1 into a shallow-rooting rice cultivar by backcrossing enabled the resulting line to avoid drought by increasing deep rooting, which maintained high yield performance under drought conditions relative to the recipient cultivar. Our experiments suggest that control of root system architecture will contribute to drought avoidance in crops.

  11. Effect of modeled microgravity on radiation-induced adaptive response of root growth in Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Deng, Chenguang; Wang, Ting; Wu, Jingjing; Xu, Wei; Li, Huasheng; Liu, Min

    2017-01-01

    Highlights: • The radio-adaptive response (RAR) of A. thaliana root growth is modulated in microgravity. • The DNA damage repairs in RAR are regulated by microgravity. • The phytohormone auxin plays a regulatory role in the modulation of microgravity on RAR of root growth. - Abstract: Space particles have an inevitable impact on organisms during space missions; radio-adaptive response (RAR) is a critical radiation effect due to both low-dose background and sudden high-dose radiation exposure during solar storms. Although it is relevant to consider RAR within the context of microgravity, another major space environmental factor, there is no existing evidence as to its effects on RAR. In the present study, we established an experimental method for detecting the effects of gamma-irradiation on the primary root growth of Arabidopsis thaliana, in which RAR of root growth was significantly induced by several dose combinations. Microgravity was simulated using a two-dimensional rotation clinostat. It was shown that RAR of root growth was significantly inhibited under the modeled microgravity condition, and was absent in pgm-1 plants that had impaired gravity sensing in root tips. These results suggest that RAR could be modulated in microgravity. Time course analysis showed that microgravity affected either the development of radio-resistance induced by priming irradiation, or the responses of plants to challenging irradiation. After treatment with the modeled microgravity, attenuation in priming irradiation-induced expressions of DNA repair genes (AtKu70 and AtRAD54), and reduced DNA repair efficiency in response to challenging irradiation were observed. In plant roots, the polar transportation of the phytohormone auxin is regulated by gravity, and treatment with an exogenous auxin (indole-3-acetic acid) prevented the induction of RAR of root growth, suggesting that auxin might play a regulatory role in the interaction between microgravity and RAR of root growth.

  12. Effect of modeled microgravity on radiation-induced adaptive response of root growth in Arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Chenguang [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences (China); Key Laboratory of Environmental Toxicology and Pollution Control Technology of Anhui Province (China); Institute of Technical Biology and Agriculture Engineering, Chinese Academy of Sciences, 350 Shushanhu Road, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Wang, Ting [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences (China); Key Laboratory of Environmental Toxicology and Pollution Control Technology of Anhui Province (China); Institute of Technical Biology and Agriculture Engineering, Chinese Academy of Sciences, 350 Shushanhu Road, Hefei 230031 (China); Wu, Jingjing [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences (China); Key Laboratory of Environmental Toxicology and Pollution Control Technology of Anhui Province (China); Institute of Technical Biology and Agriculture Engineering, Chinese Academy of Sciences, 350 Shushanhu Road, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Xu, Wei [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences (China); Key Laboratory of Environmental Toxicology and Pollution Control Technology of Anhui Province (China); Institute of Technical Biology and Agriculture Engineering, Chinese Academy of Sciences, 350 Shushanhu Road, Hefei 230031 (China); Li, Huasheng; Liu, Min [China Space Molecular Biological Lab, China Academy of Space Technology, Beijing 100086 (China); and others

    2017-02-15

    Highlights: • The radio-adaptive response (RAR) of A. thaliana root growth is modulated in microgravity. • The DNA damage repairs in RAR are regulated by microgravity. • The phytohormone auxin plays a regulatory role in the modulation of microgravity on RAR of root growth. - Abstract: Space particles have an inevitable impact on organisms during space missions; radio-adaptive response (RAR) is a critical radiation effect due to both low-dose background and sudden high-dose radiation exposure during solar storms. Although it is relevant to consider RAR within the context of microgravity, another major space environmental factor, there is no existing evidence as to its effects on RAR. In the present study, we established an experimental method for detecting the effects of gamma-irradiation on the primary root growth of Arabidopsis thaliana, in which RAR of root growth was significantly induced by several dose combinations. Microgravity was simulated using a two-dimensional rotation clinostat. It was shown that RAR of root growth was significantly inhibited under the modeled microgravity condition, and was absent in pgm-1 plants that had impaired gravity sensing in root tips. These results suggest that RAR could be modulated in microgravity. Time course analysis showed that microgravity affected either the development of radio-resistance induced by priming irradiation, or the responses of plants to challenging irradiation. After treatment with the modeled microgravity, attenuation in priming irradiation-induced expressions of DNA repair genes (AtKu70 and AtRAD54), and reduced DNA repair efficiency in response to challenging irradiation were observed. In plant roots, the polar transportation of the phytohormone auxin is regulated by gravity, and treatment with an exogenous auxin (indole-3-acetic acid) prevented the induction of RAR of root growth, suggesting that auxin might play a regulatory role in the interaction between microgravity and RAR of root growth.

  13. A New Anatomically Based Nomenclature for the Roots and Root Canals—Part 1: Maxillary Molars

    OpenAIRE

    Kottoor, Jojo; Albuquerque, Denzil Valerian; Velmurugan, Natanasabapathy

    2012-01-01

    Numerous terminologies have been employed in the dental literature to describe the roots and root canal systems of maxillary molars. This multiplicity in naming of roots and canals makes the reader susceptible to misinterpretation and confusion. No consensus thus far has been arrived at for defining the names of roots and root canals in maxillary molars, including their various morphological aberrations. The anatomical relation of roots and their root canals were identified and were subsequen...

  14. Cadmium translocation by contractile roots differs from that in regular, non-contractile roots.

    Science.gov (United States)

    Lux, Alexander; Lackovič, Andrej; Van Staden, Johannes; Lišková, Desana; Kohanová, Jana; Martinka, Michal

    2015-06-01

    Contractile roots are known and studied mainly in connection with the process of shrinkage of their basal parts, which acts to pull the shoot of the plant deeper into the ground. Previous studies have shown that the specific structure of these roots results in more intensive water uptake at the base, which is in contrast to regular root types. The purpose of this study was to find out whether the basal parts of contractile roots are also more active in translocation of cadmium to the shoot. Plants of the South African ornamental species Tritonia gladiolaris were cultivated in vitro for 2 months, at which point they possessed well-developed contractile roots. They were then transferred to Petri dishes with horizontally separated compartments of agar containing 50 µmol Cd(NO3)2 in the region of the root base or the root apex. Seedlings of 4-d-old maize (Zea mays) plants, which do not possess contractile roots, were also transferred to similar Petri dishes. The concentrations of Cd in the leaves of the plants were compared after 10 d of cultivation. Anatomical analyses of Tritonia roots were performed using appropriately stained freehand cross-sections. The process of contraction required specific anatomical adaptation of the root base in Tritonia, with less lignified and less suberized tissues in comparison with the subapical part of the root. These unusual developmental characteristics were accompanied by more intensive translocation of Cd ions from the basal part of contractile roots to the leaves than from the apical-subapical root parts. The opposite effects were seen in the non-contractile roots of maize, with higher uptake and transport by the apical parts of the root and lower uptake and transport by the basal part. The specific characteristics of contractile roots may have a significant impact on the uptake of ions, including toxic metals from the soil surface layers. This may be important for plant nutrition, for example in the uptake of nutrients from

  15. Antifungal genes expressed in transgenic pea (Pisum sativum L.) do not affect root colonization of arbuscular mycorrhizae fungi.

    Science.gov (United States)

    Kahlon, Jagroop Gill; Jacobsen, Hans-Jörg; Cahill, James F; Hall, Linda M

    2017-10-01

    Genetically modified crops have raised concerns about unintended consequences on non-target organisms including beneficial soil associates. Pea transformed with four antifungal genes 1-3 β glucanase, endochitinase, polygalacturonase-inhibiting proteins, and stilbene synthase is currently under field-testing for efficacy against fungal diseases in Canada. Transgenes had lower expression in the roots than leaves in greenhouse experiment. To determine the impact of disease-tolerant pea or gene products on colonization by non-target arbuscular mycorrhizae and nodulation by rhizobium, a field trial was established. Transgene insertion, as single gene or stacked genes, did not alter root colonization by arbuscular mycorrhiza fungus (AMF) or root nodulation by rhizobium inoculation in the field. We found no effect of transgenes on the plant growth and performance although, having a dual inoculant with both AMF and rhizobium yielded higher fresh weight shoot-to-root ratio in all the lines tested. This initial risk assessment of transgenic peas expressing antifungal genes showed no deleterious effect on non-target organisms.

  16. Inhibition of tomato (Solanum lycopersicum L.) root growth by cyanamide is not always accompanied with enhancement of ROS production.

    Science.gov (United States)

    Soltys, Dorota; Gniazdowska, Agnieszka; Bogatek, Renata

    2013-05-01

    Mode of action of allelochemicals in target plants is currently widely studied. Cyanamide is one of the newly discovered allelochemical, biosynthesized in hairy vetch. Recently, it has been recognized that cyanamide is plant growth inhibitor, which affects mitosis in root tip cells and causes,e.g., disorder in phytohormonal balance. We also demonstrated that CA may act as oxidative stress agent but it strictly depends on plant species, exposure time and doses. Roots of tomato seedling treated with water solution of 1.2 mM cyanamide did not exhibit elevated reactive oxygen species concentration during the whole culture period.

  17. Ferric Iron Reduction by Bacteria Associated with the Roots of Freshwater and Marine Macrophytes†

    Science.gov (United States)

    King, G. M.; Garey, Meredith A.

    1999-01-01

    In vitro assays of washed, excised roots revealed maximum potential ferric iron reduction rates of >100 μmol g (dry weight)−1 day−1 for three freshwater macrophytes and rates between 15 and 83 μmol (dry weight)−1 day−1 for two marine species. The rates varied with root morphology but not consistently (fine root activity exceeded smooth root activity in some but not all cases). Sodium molybdate added at final concentrations of 0.2 to 20 mM did not inhibit iron reduction by roots of marine macrophytes (Spartina alterniflora and Zostera marina). Roots of a freshwater macrophyte, Sparganium eurycarpum, that were incubated with an analog of humic acid precursors, anthroquinone disulfate (AQDS), reduced freshly precipitated iron oxyhydroxide contained in dialysis bags that excluded solutes with molecular weights of >1,000; no reduction occurred in the absence of AQDS. Bacterial enrichment cultures and isolates from freshwater and marine roots used a variety of carbon and energy sources (e.g., acetate, ethanol, succinate, toluene, and yeast extract) and ferric oxyhydroxide, ferric citrate, uranate, and AQDS as terminal electron acceptors. The temperature optima for a freshwater isolate and a marine isolate were equivalent (approximately 32°C). However, iron reduction by the freshwater isolate decreased with increasing salinity, while reduction by the marine isolate displayed a relatively broad optimum salinity between 20 and 35 ppt. Our results suggest that by participating in an active iron cycle and perhaps by reducing humic acids, iron reducers in the rhizoplane of aquatic macrophytes limit organic availability to other heterotrophs (including methanogens) in the rhizosphere and bulk sediments. PMID:10508065

  18. The stress protein heat shock cognate 70 (Hsc70) inhibits the Transient Receptor Potential Vanilloid type 1 (TRPV1) channel.

    Science.gov (United States)

    Iftinca, Mircea; Flynn, Robyn; Basso, Lilian; Melo, Helvira; Aboushousha, Reem; Taylor, Lauren; Altier, Christophe

    2016-01-01

    Specialized cellular defense mechanisms prevent damage from chemical, biological, and physical hazards. The heat shock proteins have been recognized as key chaperones that maintain cell survival against a variety of exogenous and endogenous stress signals including noxious temperature. However, the role of heat shock proteins in nociception remains poorly understood. We carried out an expression analysis of the constitutively expressed 70 kDa heat-shock cognate protein, a member of the stress-induced HSP70 family in lumbar dorsal root ganglia from a mouse model of Complete Freund's Adjuvant-induced chronic inflammatory pain. We used immunolabeling of dorsal root ganglion neurons, behavioral analysis and patch clamp electrophysiology in both dorsal root ganglion neurons and HEK cells transfected with Hsc70 and Transient Receptor Potential Channels to examine their functional interaction in heat shock stress condition. We report an increase in protein levels of Hsc70 in mouse dorsal root ganglia, 3 days post Complete Freund's Adjuvant injection in the hind paw. Immunostaining of Hsc70 was observed in most of the dorsal root ganglion neurons, including the small size nociceptors immunoreactive to the TRPV1 channel. Standard whole-cell patch-clamp technique was used to record Transient Receptor Potential Vanilloid type 1 current after exposure to heat shock. We found that capsaicin-evoked currents are inhibited by heat shock in dorsal root ganglion neurons and transfected HEK cells expressing Hsc70 and TRPV1. Blocking Hsc70 with matrine or spergualin compounds prevented heat shock-induced inhibition of the channel. We also found that, in contrast to TRPV1, both the cold sensor channels TRPA1 and TRPM8 were unresponsive to heat shock stress. Finally, we show that inhibition of TRPV1 depends on the ATPase activity of Hsc70 and involves the rho-associated protein kinase. Our work identified Hsc70 and its ATPase activity as a central cofactor of TRPV1 channel function

  19. Root type matters: measurements of water uptake by seminal, crown and lateral roots of maize

    Science.gov (United States)

    Ahmed, Mutez Ali; Zarebanadkouki, Mohsen; Kaestner, Anders; Carminati, Andrea

    2016-04-01

    Roots play a key role in water acquisition and are a significant component of plant adaptation to different environmental conditions. Although maize (Zea mays L.) is one of the most important crops worldwide, there is limited information on the function of different root segments and types in extracting water from soils. Aim of this study was to investigate the location of root water uptake in mature maize. We used neutron radiography to image the spatial distribution of maize roots and trace the transport of injected deuterated water (D2O) in soil and roots. Maize plants were grown in aluminum containers filled with a sandy soil that was kept homogeneously wet throughout the experiment. When the plants were five weeks-old, we injected D2O into selected soil regions. The transport of D2O was simulated using a diffusion-convection numerical model. By fitting the observed D2O transport we quantified the diffusion coefficient and the water uptake of the different root segments. The model was initially developed and tested with two weeks-old maize (Ahmed et. al. 2015), for which we found that water was mainly taken up by lateral roots and the water uptake of the seminal roots was negligible. Here, we used this method to measure root water uptake in a mature maize root system. The root architecture of five weeks-old maize consisted of primary and seminal roots with long laterals and crown (nodal) roots that emerged from the above ground part of the plant two weeks after planting. The crown roots were thicker than the seminal roots and had fewer and shorter laterals. Surprisingly, we found that the water was mainly taken up by the crown roots and their laterals, while the lateral roots of seminal roots, which were the main location of water uptake of younger plants, stopped to take up water. Interestingly, we also found that in contrast to the seminal roots, the crown roots were able to take up water also from their distal segments. We conclude that for the two weeks

  20. ROOT HYDRAULIC CONDUCTIVITY AND PHOTOSYNTHETIC CAPACITY OF EUCALYPT CLONAL CUTTINGS WITH ROOT MALFORMATION INDUCTIONS

    Directory of Open Access Journals (Sweden)

    Fábio Afonso Mazzei Moura de Assis Figueiredo

    2014-06-01

    Full Text Available http://dx.doi.org/10.5902/1980509814566The gain reduction of wood biomass in trees has been assigned to root deformations even in the nursery phase. The objective of this work was the evaluation of the root system hydraulic conductivity, gas exchanges and photochemical efficiency of eucalypt clonal cuttings with and without root deformation inductions. The treatments were: 1 operational cuttings without root malformation inductions (grown according to the used methodology of Fibria Cellulose S.A.; 2 root deformation inductions. These inductions did not promote decrease in the root volume. However, the deformations brought reduction of the root system hydraulic conductivity. Lower photosynthetic rates were also observed along the day in the cuttings in the root deformed cuttings. This decreasing rate is connected to stomatal and non stomatal factors.

  1. PHIV-RootCell: a supervised image analysis tool for rice root anatomical parameter quantification

    Directory of Open Access Journals (Sweden)

    Marc eLartaud

    2015-01-01

    Full Text Available We developed the PHIV-RootCell software to quantify anatomical traits of rice roots transverse section images. Combined with an efficient root sample processing method for image acquisition, this program permits supervised measurements of areas (those of whole root section, stele, cortex and central metaxylem vessels, number of cell layers and number of cells per cell layer. The PHIV-RootCell toolset runs under ImageJ, an independent operating system that has a license-free status. To demonstrate the usefulness of PHIV-RootCell, we conducted a genetic diversity study and an analysis of salt-stress responses of root anatomical parameters in rice (Oryza sativa L.. Using 16 cultivars, we showed that we could discriminate between some of the varieties even at the 6 day-old stage, and that tropical japonica varieties had larger root sections due to an increase in cell number. We observed, as described previously, that root sections become enlarged under salt stress. However, our results show an increase in cell number in ground tissues (endodermis and cortex but a decrease in external (peripheral tissues (sclerenchyma, exodermis and epidermis. Thus, the PHIV-RootCell program is a user-friendly tool that will be helpful for future genetic and physiological studies that investigate root anatomical trait variations.

  2. Root deformation reduces tolerance of lodgepole pine to attack by Warren root collar weevil.

    Science.gov (United States)

    Robert, Jeanne A; Lindgren, B Staffan

    2010-04-01

    Surveys were conducted on regenerating stands of lodgepole pine to determine the relationship between root deformation and susceptibility to attack by the Warren root collar weevil, Hylobius warreni Wood. The total number of trees attacked by H. warreni did not differ between planted and natural trees. A matched case-control logistic regression suggested that root cross-sectional area was more important in predicting weevil attack for naturally regenerated trees than for planted trees, but weevils were associated with a larger reduction in height-to-diameter ratios for trees with planted root characteristics than for trees with natural root form. Neither the stability of attacked versus unattacked trees differed significantly and there was no significant interaction of weevil attack and tree type, but weevil-killed trees had different root characteristics than alive, attacked trees. Lateral distribution and root cross-sectional area were significant predictors of alive attacked trees versus weevil-killed trees, suggesting that trees with poor lateral spread or poor root cross-sectional area are more likely to die from weevil attack. We conclude that root deformation does not necessarily increase susceptibility to attack but may increase the likelihood of mortality. Thus, measures to facilitate good root form are needed when planting pine in areas with high risk of Warren root collar weevil attack.

  3. Plant roots use a patterning mechanism to position lateral root branches toward available water.

    Science.gov (United States)

    Bao, Yun; Aggarwal, Pooja; Robbins, Neil E; Sturrock, Craig J; Thompson, Mark C; Tan, Han Qi; Tham, Cliff; Duan, Lina; Rodriguez, Pedro L; Vernoux, Teva; Mooney, Sacha J; Bennett, Malcolm J; Dinneny, José R

    2014-06-24

    The architecture of the branched root system of plants is a major determinant of vigor. Water availability is known to impact root physiology and growth; however, the spatial scale at which this stimulus influences root architecture is poorly understood. Here we reveal that differences in the availability of water across the circumferential axis of the root create spatial cues that determine the position of lateral root branches. We show that roots of several plant species can distinguish between a wet surface and air environments and that this also impacts the patterning of root hairs, anthocyanins, and aerenchyma in a phenomenon we describe as hydropatterning. This environmental response is distinct from a touch response and requires available water to induce lateral roots along a contacted surface. X-ray microscale computed tomography and 3D reconstruction of soil-grown root systems demonstrate that such responses also occur under physiologically relevant conditions. Using early-stage lateral root markers, we show that hydropatterning acts before the initiation stage and likely determines the circumferential position at which lateral root founder cells are specified. Hydropatterning is independent of endogenous abscisic acid signaling, distinguishing it from a classic water-stress response. Higher water availability induces the biosynthesis and transport of the lateral root-inductive signal auxin through local regulation of tryptophan aminotransferase of Arabidopsis 1 and PIN-formed 3, both of which are necessary for normal hydropatterning. Our work suggests that water availability is sensed and interpreted at the suborgan level and locally patterns a wide variety of developmental processes in the root.

  4. 1-Aminocyclopropane-1-carboxylic acid (ACC) concentration and ACC synthase expression in soybean roots, root tips, and soybean cyst nematode (Heterodera glycines)-infected roots.

    Science.gov (United States)

    Tucker, Mark L; Xue, Ping; Yang, Ronghui

    2010-01-01

    Colonization of plant roots by root knot and cyst nematodes requires a functional ethylene response pathway. However, ethylene plays many roles in root development and whether its role in nematode colonization is direct or indirect, for example lateral root initiation or root hair growth, is not known. The temporal requirement for ethylene and localized synthesis of ethylene during the life span of soybean cyst nematode (SCN) on soybean roots was further investigated. Although a significant increase in ethylene evolution was not detected from SCN-colonized roots, the concentration of the immediate precursor to ethylene, 1-aminocyclopropane-1-carboxylic acid (ACC), was higher in SCN-colonized root pieces and root tips than in other parts of the root. Moreover, expression analysis of 17 ACC synthase (ACS) genes indicated that a select set of ACS genes is expressed in SCN-colonized root pieces that is clearly different from the set of genes expressed in non-colonized roots or root tips. Semi-quantitative real-time PCR indicated that ACS transcript accumulation correlates with the high concentration of ACC in root tips. In addition, an ACS-like sequence was found in the public SCN nucleotide database. Acquisition of a full-length sequence for this mRNA (accession GQ389647) and alignment with transcripts for other well-characterized ACS proteins indicated that the nematode sequence is missing a key element required for ACS activity and therefore probably is not a functional ACS. Moreover, no significant amount of ACC was found in any growth stage of SCN that was tested.

  5. RNAi inhibition of feruloyl CoA 6'-hydroxylase reduces scopoletin biosynthesis and post-harvest physiological deterioration in cassava (Manihot esculenta Crantz) storage roots.

    Science.gov (United States)

    Liu, Shi; Zainuddin, Ima M; Vanderschuren, Herve; Doughty, James; Beeching, John R

    2017-05-01

    Cassava (Manihot esculenta Crantz) is a major world crop, whose storage roots provide food for over 800 million throughout the humid tropics. Despite many advantages as a crop, the development of cassava is seriously constrained by the rapid post-harvest physiological deterioration (PPD) of its roots that occurs within 24-72 h of harvest, rendering the roots unpalatable and unmarketable. PPD limits cassava's marketing possibilities in countries that are undergoing increased development and urbanisation due to growing distances between farms and consumers. The inevitable wounding of the roots caused by harvesting triggers an oxidative burst that spreads throughout the cassava root, together with the accumulation of secondary metabolites including phenolic compounds, of which the coumarin scopoletin (7-hydroxy-6-methoxy-2H-1-benzopyran-2-one) is the most abundant. Scopoletin oxidation yields a blue-black colour, which suggests its involvement in the discoloration observed during PPD. Feruloyl CoA 6'-hydroxylase is a controlling enzyme in the biosynthesis of scopoletin. The cassava genome contains a seven membered family of feruloyl CoA 6'-hydroxylase genes, four of which are expressed in the storage root and, of these, three were capable of functionally complementing Arabidopsis T-DNA insertion mutants in this gene. A RNA interference construct, designed to a highly conserved region of these genes, was used to transform cassava, where it significantly reduced feruloyl CoA 6'-hydroxylase gene expression, scopoletin accumulation and PPD symptom development. Collectively, our results provide evidence that scopoletin plays a major functional role in the development of PPD symptoms, rather than merely paralleling symptom development in the cassava storage root.

  6. Abscisic acid regulates root growth under osmotic stress conditions via an interacting hormonal network with cytokinin, ethylene and auxin.

    Science.gov (United States)

    Rowe, James H; Topping, Jennifer F; Liu, Junli; Lindsey, Keith

    2016-07-01

    Understanding the mechanisms regulating root development under drought conditions is an important question for plant biology and world agriculture. We examine the effect of osmotic stress on abscisic acid (ABA), cytokinin and ethylene responses and how they mediate auxin transport, distribution and root growth through effects on PIN proteins. We integrate experimental data to construct hormonal crosstalk networks to formulate a systems view of root growth regulation by multiple hormones. Experimental analysis shows: that ABA-dependent and ABA-independent stress responses increase under osmotic stress, but cytokinin responses are only slightly reduced; inhibition of root growth under osmotic stress does not require ethylene signalling, but auxin can rescue root growth and meristem size; osmotic stress modulates auxin transporter levels and localization, reducing root auxin concentrations; PIN1 levels are reduced under stress in an ABA-dependent manner, overriding ethylene effects; and the interplay among ABA, ethylene, cytokinin and auxin is tissue-specific, as evidenced by differential responses of PIN1 and PIN2 to osmotic stress. Combining experimental analysis with network construction reveals that ABA regulates root growth under osmotic stress conditions via an interacting hormonal network with cytokinin, ethylene and auxin. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  7. Air lateral root pruning affects longleaf pine seedling root system morphology

    Science.gov (United States)

    Shi-Jean Susana Sung; Dave Haywood

    2016-01-01

    Longleaf pine (Pinus palustris) seedlings were cultured with air lateral root pruning (side-vented containers, VT) or without (solid-walled containers, SW). Seedling root system morphology and growth were assessed before planting and 8 and 14 months after planting. Although VT seedlings had greater root collar diameter than the SW before planting,...

  8. Relationships between root respiration rate and root morphology, chemistry and anatomy in Larix gmelinii and Fraxinus mandshurica.

    Science.gov (United States)

    Jia, Shuxia; McLaughlin, Neil B; Gu, Jiacun; Li, Xingpeng; Wang, Zhengquan

    2013-06-01

    Tree roots are highly heterogeneous in form and function. Previous studies revealed that fine root respiration was related to root morphology, tissue nitrogen (N) concentration and temperature, and varied with both soil depth and season. The underlying mechanisms governing the relationship between root respiration and root morphology, chemistry and anatomy along the root branch order have not been addressed. Here, we examined these relationships of the first- to fifth-order roots for near surface roots (0-10 cm) of 22-year-old larch (Larix gmelinii L.) and ash (Fraxinus mandshurica L.) plantations. Root respiration rate at 18 °C was measured by gas phase O2 electrodes across the first five branching order roots (the distal roots numbered as first order) at three times of the year. Root parameters of root diameter, specific root length (SRL), tissue N concentration, total non-structural carbohydrates (starch and soluble sugar) concentration (TNC), cortical thickness and stele diameter were also measured concurrently. With increasing root order, root diameter, TNC and the ratio of root TNC to tissue N concentration increased, while the SRL, tissue N concentration and cortical proportion decreased. Root respiration rate also monotonically decreased with increasing root order in both species. Cortical tissue (including exodermis, cortical parenchyma and endodermis) was present in the first three order roots, and cross sections of the cortex for the first-order root accounted for 68% (larch) and 86% (ash) of the total cross section of the root. Root respiration was closely related to root traits such as diameter, SRL, tissue N concentration, root TNC : tissue N ratio and stele-to-root diameter proportion among the first five orders, which explained up to 81-94% of variation in the rate of root respiration for larch and up to 83-93% for ash. These results suggest that the systematic variations of root respiration rate within tree fine root system are possibly due to the

  9. Model Persamaan Massa Karbon Akar Pohon dan Root-Shoot Ratio Massa Karbon (Equation Models of Tree Root Carbon Mass and Root-Shoot Carbon Mass Ratio

    Directory of Open Access Journals (Sweden)

    Elias .

    2011-03-01

    Full Text Available The case study was conducted in the area of Acacia mangium plantation at BKPH Parung Panjang, KPH Bogor. The objective of the study was to formulate equation models of tree root carbon mass and root to shoot carbon mass ratio of the plantation. It was found that carbon content in the parts of tree biomass (stems, branches, twigs, leaves, and roots was different, in which the highest and the lowest carbon content was in the main stem of the tree and in the leaves, respectively. The main stem and leaves of tree accounted for 70% of tree biomass. The root-shoot ratio of root biomass to tree biomass above the ground and the root-shoot ratio of root biomass to main stem biomass was 0.1443 and 0.25771, respectively, in which 75% of tree carbon mass was in the main stem and roots of tree. It was also found that the root-shoot ratio of root carbon mass to tree carbon mass above the ground and the root-shoot ratio of root carbon mass to tree main stem carbon mass was 0.1442 and 0.2034, respectively. All allometric equation models of tree root carbon mass of A. mangium have a high goodness-of-fit as indicated by its high adjusted R2.Keywords: Acacia mangium, allometric, root-shoot ratio, biomass, carbon mass

  10. Low Light Availability Alters Root Exudation and Reduces Putative Beneficial Microorganisms in Seagrass Roots

    Directory of Open Access Journals (Sweden)

    Belinda C. Martin

    2018-01-01

    Full Text Available Seagrass roots host a diverse microbiome that is critical for plant growth and health. Composition of microbial communities can be regulated in part by root exudates, but the specifics of these interactions in seagrass rhizospheres are still largely unknown. As light availability controls primary productivity, reduced light may impact root exudation and consequently the composition of the root microbiome. Hence, we analyzed the influence of light availability on root exudation and community structure of the root microbiome of three co-occurring seagrass species, Halophila ovalis, Halodule uninervis and Cymodocea serrulata. Plants were grown under four light treatments in mesocosms for 2 weeks; control (100% surface irradiance (SI, medium (40% SI, low (20% SI and fluctuating light (10 days 20% and 4 days 100%. 16S rDNA amplicon sequencing revealed that microbial diversity, composition and predicted function were strongly influenced by the presence of seagrass roots, such that root microbiomes were unique to each seagrass species. Reduced light availability altered seagrass root exudation, as characterized using fluorescence spectroscopy, and altered the composition of seagrass root microbiomes with a reduction in abundance of potentially beneficial microorganisms. Overall, this study highlights the potential for above-ground light reduction to invoke a cascade of changes from alterations in root exudation to a reduction in putative beneficial microorganisms and, ultimately, confirms the importance of the seagrass root environment – a critical, but often overlooked space.

  11. Root patterning

    NARCIS (Netherlands)

    Scheres, Ben; Laskowski, Marta

    2016-01-01

    The mechanisms that pattern lateral root primordial are essential for the elaboration of root system architecture, a trait of key importance for future crop breeding. But which are most important: periodic or local cues? In this issue of Journal of Experimental Botany (pages 1411-1420), Kircher

  12. iRoot FM exerts an antibacterial effect on Porphyromonas endodontalis and improves the properties of stem cells from the apical papilla.

    Science.gov (United States)

    Bi, J; Liu, Y; Liu, X M; Jiang, L M; Chen, X

    2018-03-07

    To investigate the antibacterial activity of a novel intracanal medicament, iRoot FM, against Porphyromonas endodontalis and its effects on the proliferation and osteo-/odontogenic differentiation of stem cells from apical papilla (SCAP). The agar diffusion test was used to compare the antimicrobial efficacy of iRoot FM with two traditional intracanal medicaments, calcium hydroxide [Ca(OH) 2 ] and triple antibiotic paste (TAP). The CCK-8 assay was used to assess the proliferation rate of SCAP when exposed to the three intracanal medicaments. The expression levels of ALP and DMP-1 and the capacity to form mineralized nodules were used to evaluate the osteo-/odontogenic differentiation of SCAP, as assessed by real-time PCR, Western blotting and alizarin red S staining. Data were statistically analysed with one-way analysis of variance (anova), and comparisons between each of two groups were analysed by the least significance difference method. P values less than 0.05 were considered statistically significant. The zone of inhibition against P. endodontalis produced by iRoot FM was 20.74 ± 4.35 mm, whilst the zones of inhibition of Ca(OH) 2 and TAP were 24.89 ± 3.84 mm and 34.51 ± 1.20 mm. The antibacterial capacity of iRoot FM was similar to that of Ca(OH) 2 (P > 0.05). SCAP, cultured in conditioned medium with iRoot FM, was associated with greater proliferation and osteo-/odontogenic differentiation capacity than those cultured in conditioned medium with Ca(OH) 2 and TAP (P endodontalis and could improve the proliferation and differentiation of SCAP. The findings provide evidence that iRoot FM has potential as an intracanal medicament for endodontic procedures in immature permanent teeth. © 2018 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  13. Silicon improves salt tolerance by increasing root water uptake in Cucumis sativus L.

    Science.gov (United States)

    Zhu, Yong-Xing; Xu, Xuan-Bin; Hu, Yan-Hong; Han, Wei-Hua; Yin, Jun-Liang; Li, Huan-Li; Gong, Hai-Jun

    2015-09-01

    Silicon enhances root water uptake in salt-stressed cucumber plants through up-regulating aquaporin gene expression. Osmotic adjustment is a genotype-dependent mechanism for silicon-enhanced water uptake in plants. Silicon can alleviate salt stress in plants. However, the mechanism is still not fully understood, and the possible role of silicon in alleviating salt-induced osmotic stress and the underlying mechanism still remain to be investigated. In this study, the effects of silicon (0.3 mM) on Na accumulation, water uptake, and transport were investigated in two cucumber (Cucumis sativus L.) cultivars ('JinYou 1' and 'JinChun 5') under salt stress (75 mM NaCl). Salt stress inhibited the plant growth and photosynthesis and decreased leaf transpiration and water content, while added silicon ameliorated these negative effects. Silicon addition only slightly decreased the shoot Na levels per dry weight in 'JinYou 1' but not in 'JinChun 5' after 10 days of stress. Silicon addition reduced stress-induced decreases in root hydraulic conductivity and/or leaf-specific conductivity. Expressions of main plasma membrane aquaporin genes in roots were increased by added silicon, and the involvement of aquaporins in water uptake was supported by application of aquaporin inhibitor and restorative. Besides, silicon application decreased the root xylem osmotic potential and increased root soluble sugar levels in 'JinYou 1.' Our results suggest that silicon can improve salt tolerance of cucumber plants through enhancing root water uptake, and silicon-mediated up-regulation of aquaporin gene expression may in part contribute to the increase in water uptake. In addition, osmotic adjustment may be a genotype-dependent mechanism for silicon-enhanced water uptake in plants.

  14. Effect of root contact on N uptake distribution in intercropped soybean and hedgerow

    International Nuclear Information System (INIS)

    Guo Zhonglu; Cai Chongfa; Zhong Cheng; Wang Zhongmin

    2012-01-01

    Below-ground for nutrients and water can be clue to the cause of the reduction of crops yields. Root interaction plays on important role in estimating the effect of below-ground competition. However, little information had been known about these hedgerows-crops interaction in contour hedgerow agroforestry. Pot experiments were conducted to study the effect of root contact on N absorption and transfer in purple soil of two hedges-soybean intercropping systems with two different methods of 15 N foliar-feeding and 15 N soil labeling methods, along with root partition, i. e., a sheet barrier treatment, a mesh barrier, and no barrier treatment. Results showed that the growth of Amorpha. fruticosa was suppressed without root barrier, leading to lower biomass and N acquisition than those with mesh and sheet barrier; the biomass and N acquisition of Vertiveria zizanioide and soybean without root barrier were the highest in Vertiver intercropping system. The 15 N abundance is higher in soybean and A. fruticosa with mesh barrier, but 15 N abundance is higher in Vertiver without root barrier, which suggested that the Vertiver is a stronger competitor in Vertiver/soybean intercropping system. N transfer from soybean to hedge species was obvious using 15 N direct labeling methods, which suggested that competition between of A. fruticosa or Vertiver for nitrogen fertilizer was stronger. Interspecific inhibition did exist in A. fruticosa-soybean intercropping, and the growth of A. fruticosa and soybean were suppressed; the complementary nitrogen use did exist in Vertiver-soybean intercropping, and both competition and facilitation occurred in Vertiver-soybean intercropping which enhanced the growth of Vertiver and soybean. (authors)

  15. Evidence that L-glutamate can act as an exogenous signal to modulate root growth and branching in Arabidopsis thaliana.

    Science.gov (United States)

    Walch-Liu, Pia; Liu, Lai-Hua; Remans, Tony; Tester, Mark; Forde, Brian G

    2006-08-01

    The roots of many plant species are known to use inorganic nitrogen, in the form of , as a cue to initiate localized root proliferation within nutrient-rich patches of soil. We report here that, at micromolar concentrations and in a genotype-dependent manner, exogenous l-glutamate is also able to elicit complex changes in Arabidopsis root development. l-Glutamate is perceived specifically at the primary root tip and inhibits mitotic activity in the root apical meristem, but does not interfere with lateral root initiation or outgrowth. Only some time after emergence do lateral roots acquire l-glutamate sensitivity, indicating that their ability to respond to l-glutamate is developmentally regulated. Comparisons between different Arabidopsis ecotypes revealed a remarkable degree of natural variation in l-glutamate sensitivity, with C24 being the most sensitive. The aux1-7 auxin transport mutant had reduced l-glutamate sensitivity, suggesting a possible interaction between l-glutamate and auxin signaling. Surprisingly, two loss-of-function mutants at the AXR1 locus (axr1-3 and axr1-12) were hypersensitive to l-glutamate. A pharmacological approach, using agonists and antagonists of mammalian ionotropic glutamate receptors, was unable to provide evidence of a role for their plant homologs in sensing exogenous glutamate. We discuss the mechanism of l-glutamate sensing and the possible ecological significance of the observed l-glutamate-elicited changes in root architecture.

  16. Radiomimetic effect of cisplatin on cucumber root development: the relationship between cell division and cell growth

    Energy Technology Data Exchange (ETDEWEB)

    Dubrovsky, J. G. [Division of Experimental Biology, Center for Biological Research (CIB), PO Box 128, La Paz, BCS 23000 (Mexico)

    1993-07-01

    Cisplatin [DDP, cis-dichlorodiammine platinum (II)], a strong cytostatic and antineoplastic agent, was tested on seedlings of cucumber Cucumis sativus L. for its general effect on root development and its particular effects on root cell division and cell growth. DDP was characterized as a radiomimetic compound since both DDP (1·3 × 10{sup -5} M) and γ-irradiation (2·5-10 kGy) drastically and irreversibly stopped development of embryonic lateral root primordia (LRPs) in the radicle by inhibiting both mitotic activity and cell growth. In 20% of the LRPs of DDP-treated roots, cells did not divide at all. Dividing cells completed no more than two cell cycles. These effects were specific because when DDP was available to the roots only at the onset of cell division, cell proliferation and cell growth were similar to that produced by constant incubation. Neither DDP nor γ-irradiation affected non-meristematic cell elongation. It was concluded that cell growth of meristematic cells is closely related to cell division. However, non-meristematic cell growth is independent of DNA damage. This suggests DDP as a tool to reveal these autonomous processes in plants development and to detect tissue compartments in mature plant embryos which contain potentially non-meristematic cells. (author)

  17. Systemic control of cell division and endoreduplication by NAA and BAP by modulating CDKs in root tip cells of Allium cepa.

    Science.gov (United States)

    Tank, Jigna G; Thaker, Vrinda S

    2014-01-01

    Molecular mechanism regulated by auxin and cytokinin during endoreduplication, cell division, and elongation process is studied by using Allium cepa roots as a model system. The activity of CDK genes modulated by auxin and cytokinin during cell division, elongation, and endoreduplication process is explained in this research work. To study the significance of auxin and cytokinin in the management of cell division and endoreduplication process in plant meristematic cells at molecular level endoreduplication was developed in root tips of Allium cepa by giving colchicine treatment. There were inhibition of vegetative growth, formation of c-tumor at root tip, and development of endoreduplicated cells after colchicine treatment. This c-tumor was further treated with NAA and BAP to reinitiate vegetative growth in roots. BAP gave positive response in reinitiation of vegetative growth of roots from center of c-tumor. However, NAA gave negative response in reinitiation of vegetative growth of roots from c-tumor. Further, CDKs gene expression analysis from normal, endoreduplicated, and phytohormone (NAA or BAP) treated root tip was done and remarkable changes in transcription level of CDK genes in normal, endoreduplicated, and phytohormones treated cells were observed.

  18. A New Anatomically Based Nomenclature for the Roots and Root Canals—Part 1: Maxillary Molars

    Directory of Open Access Journals (Sweden)

    Jojo Kottoor

    2012-01-01

    Full Text Available Numerous terminologies have been employed in the dental literature to describe the roots and root canal systems of maxillary molars. This multiplicity in naming of roots and canals makes the reader susceptible to misinterpretation and confusion. No consensus thus far has been arrived at for defining the names of roots and root canals in maxillary molars, including their various morphological aberrations. The anatomical relation of roots and their root canals were identified and were subsequently named based on definite sets of criteria. A new method for identification and naming of roots and root canal anatomy in maxillary molars, based on their root and canal relationship, was formulated and is presented in this paper. The nomenclature makes certain essential modifications to the traditional approach to accommodate naming of the various aberrations presented in the maxillary molars. A simple, yet extensive, nomenclature system has been proposed that appropriately names the internal and external morphology of maxillary molars.

  19. A new anatomically based nomenclature for the roots and root canals-part 1: maxillary molars.

    Science.gov (United States)

    Kottoor, Jojo; Albuquerque, Denzil Valerian; Velmurugan, Natanasabapathy

    2012-01-01

    Numerous terminologies have been employed in the dental literature to describe the roots and root canal systems of maxillary molars. This multiplicity in naming of roots and canals makes the reader susceptible to misinterpretation and confusion. No consensus thus far has been arrived at for defining the names of roots and root canals in maxillary molars, including their various morphological aberrations. The anatomical relation of roots and their root canals were identified and were subsequently named based on definite sets of criteria. A new method for identification and naming of roots and root canal anatomy in maxillary molars, based on their root and canal relationship, was formulated and is presented in this paper. The nomenclature makes certain essential modifications to the traditional approach to accommodate naming of the various aberrations presented in the maxillary molars. A simple, yet extensive, nomenclature system has been proposed that appropriately names the internal and external morphology of maxillary molars.

  20. Autoradiographic study of gamma-ray induced unscheduled DNA synthesis in bean root meristem cells

    International Nuclear Information System (INIS)

    Liu Zhenshen; Qiu Quanfa; Chen Dongli

    1989-01-01

    The gamma-ray induced unscheduled DNA synthesis in root meristem cells of Vica faba was studied autoradiographically by calculating the number of cells with different 3H-thymidine labelling degree. It was found that the level of unscheduled synthesis in cells with intermediate dose (500 R) irradiation was higher than that in cells with lower dose (250 R) irradiation; however, higher dose (1000 R) irradiation would inhibit the reparative replication