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Sample records for gravistimulated maize roots

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Proteomics of Maize Root Development.

    Science.gov (United States)

    Hochholdinger, Frank; Marcon, Caroline; Baldauf, Jutta A; Yu, Peng; Frey, Felix P

    2018-01-01

    Maize forms a complex root system with structurally and functionally diverse root types that are formed at different developmental stages to extract water and mineral nutrients from soil. In recent years proteomics has been intensively applied to identify proteins involved in shaping the three-dimensional architecture and regulating the function of the maize root system. With the help of developmental mutants, proteomic changes during the initiation and emergence of shoot-borne, lateral and seminal roots have been examined. Furthermore, root hairs were surveyed to understand the proteomic changes during the elongation of these single cell type structures. In addition, primary roots have been used to study developmental changes of the proteome but also to investigate the proteomes of distinct tissues such as the meristematic zone, the elongation zone as well as stele and cortex of the differentiation zone. Moreover, subcellular fractions of the primary root including cell walls, plasma membranes and secreted mucilage have been analyzed. Finally, the superior vigor of hybrid seedling roots compared to their parental inbred lines was studied on the proteome level. In summary, these studies provide novel insights into the complex proteomic interactions of the elaborate maize root system during development.

  6. Proteomics of Maize Root Development

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    Frank Hochholdinger

    2018-03-01

    Full Text Available Maize forms a complex root system with structurally and functionally diverse root types that are formed at different developmental stages to extract water and mineral nutrients from soil. In recent years proteomics has been intensively applied to identify proteins involved in shaping the three-dimensional architecture and regulating the function of the maize root system. With the help of developmental mutants, proteomic changes during the initiation and emergence of shoot-borne, lateral and seminal roots have been examined. Furthermore, root hairs were surveyed to understand the proteomic changes during the elongation of these single cell type structures. In addition, primary roots have been used to study developmental changes of the proteome but also to investigate the proteomes of distinct tissues such as the meristematic zone, the elongation zone as well as stele and cortex of the differentiation zone. Moreover, subcellular fractions of the primary root including cell walls, plasma membranes and secreted mucilage have been analyzed. Finally, the superior vigor of hybrid seedling roots compared to their parental inbred lines was studied on the proteome level. In summary, these studies provide novel insights into the complex proteomic interactions of the elaborate maize root system during development.

  7. 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.

  8. Temperature sensing by primary roots of maize

    Science.gov (United States)

    Poff, K. L.

    1990-01-01

    Zea mays L. seedlings, grown on agar plates at 26 degrees C, reoriented the original vertical direction of their primary root when exposed to a thermal gradient applied perpendicular to the gravity vector. The magnitude and direction of curvature can not be explained simply by either a temperature or a humidity effect on root elongation. It is concluded that primary roots of maize sense temperature gradients in addition to sensing the gravitational force.

  9. Effect of Replacement of Maize with Cassava Root Meal Fortified ...

    African Journals Online (AJOL)

    The effects of replacement of maize with cassava root meal (CRM) fortified with palm oil on performance of starter broilers were determined in a 28-day feeding trial. Diets T2, T3, T4 and T5 were formulated such that they contained cassava root meal, fortified with 20% palm oil, in the proportions 10, 20, 30 and 40%, ...

  10. Impact of selection on maize root traits and rhizosphere interactions

    Science.gov (United States)

    Schmidt, J. E.; Gaudin, A. C. M.

    2017-12-01

    Effects of domestication and breeding on maize have been well-characterized aboveground, but impacts on root traits and rhizosphere processes remain unclear. Breeding in high-inorganic-input environments may have negatively affected the ability of modern maize to acquire nutrients through foraging and microbial interactions in marginal and/or organically managed soils. Twelve maize genotypes representing a selection gradient (teosintes, landraces, open-pollinated parents of modern elite germplasm, and modern hybrids released 1934-2015) were grown in three soils varying in intensity of long-term management (unfertilized, organic, conventional) in the greenhouse. Recruitment of rhizosphere microbial communities, nutrient acquisition, and plant productivity were affected by genotype-by-soil interactions. Maize genotypes exhibit significant variation in their ability to obtain nutrients from soils of different management history, indicating the potential for re-integration of beneficial root and rhizosphere traits to increase adaptation to low-input agroecosystems.

  11. The electrical network of maize root apex is gravity dependent.

    Science.gov (United States)

    Masi, Elisa; Ciszak, Marzena; Comparini, Diego; Monetti, Emanuela; Pandolfi, Camilla; Azzarello, Elisa; Mugnai, Sergio; Baluška, Frantisek; Mancuso, Stefano

    2015-01-15

    Investigations carried out on maize roots under microgravity and hypergravity revealed that gravity conditions have strong effects on the network of plant electrical activity. Both the duration of action potentials (APs) and their propagation velocities were significantly affected by gravity. Similarly to what was reported for animals, increased gravity forces speed-up APs and enhance synchronized electrical events also in plants. The root apex transition zone emerges as the most active, as well as the most sensitive, root region in this respect.

  12. 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

  13. Root type matters: measurements of water uptake by seminal, crown and lateral roots of maize

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    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

  14. 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.

  15. Hardpan and maize root distribution under conservation and ...

    African Journals Online (AJOL)

    Hardpan and maize root distribution under conservation and conventional tillage in agro-ecological zone IIa, Zambia. ... There is no scientific basis for the recommendation given to farmers by agricultural extension workers to “break the hardpan” in fields under manual or animal tillage in the study areas. Key Words: Soil ...

  16. Synergy between root hydrotropic response and root biomass in maize (Zea mays L.) enhances drought avoidance.

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    Eapen, Delfeena; Martínez-Guadarrama, Jesús; Hernández-Bruno, Oralia; Flores, Leonardo; Nieto-Sotelo, Jorge; Cassab, Gladys I

    2017-12-01

    Roots of higher plants change their growth direction in response to moisture, avoiding drought and gaining maximum advantage for development. This response is termed hydrotropism. There have been few studies of root hydrotropism in grasses, particularly in maize. Our goal was to test whether an enhanced hydrotropic response of maize roots correlates with a better adaptation to drought and partial/lateral irrigation in field studies. We developed a laboratory bioassay for testing hydrotropic response in primary roots of 47 maize elite DTMA (Drought Tolerant Maize for Africa) hybrids. After phenotyping these hybrids in the laboratory, selected lines were tested in the field. Three robust and three weak hybrids were evaluated employing three irrigation procedures: normal irrigation, partial lateral irrigation and drought. Hybrids with a robust hydrotropic response showed growth and developmental patterns, under drought and partial lateral irrigation, that differed from weak hydrotropic responders. A correlation between root crown biomass and grain yield in hybrids with robust hydrotropic response was detected. Hybrids with robust hydrotropic response showed earlier female flowering whereas several root system traits, such as projected root area, median width, maximum width, skeleton width, skeleton nodes, average tip diameter, rooting depth skeleton, thinner aboveground crown roots, as well as stem diameter, were considerably higher than in weak hydrotropic responders in the three irrigation procedures utilized. These results demonstrate the benefit of intensive phenotyping of hydrotropism in primary roots since maize plants that display a robust hydrotropic response grew better under drought and partial lateral irrigation, indicating that a selection for robust hydrotropism might be a promising breeding strategy to improve drought avoidance in maize. Copyright © 2017 Elsevier B.V. All rights reserved.

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

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    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.

  18. Source and magnitude of ammonium generation in maize roots

    International Nuclear Information System (INIS)

    Feng, J.; Vol, R.J.; Jackson, W.A.

    1998-01-01

    Studies with 15 N indicate that appreciable generation of NH 4 + from endogenous sources accompanies the uptake and assimilation of exogenous NH 4 + by roots. To identify the source of NH 4 + generation, maize (Zea mays L.) seedlings were grown on 14 NH 4 + and then exposed for 3 d to highly labeled 15 NH 4 + . More of the entering 15 NH 4 + was incorporated into the protein-N fraction of roots in darkness (approximately 25%) than in the light (approximately 14%). Although the 14 NH 4 + content of roots declined rapidly to less than 1 micromole per plant, efflux of 14 NH 4 + continued throughout the 3-d period at an average daily rate of 14 micromole per plant. As a consequence, cumulative 14 NH 4 + efflux during the 3-d period accounted for 25% of the total 14 N initially present in the root. Although soluble organic 14 N in roots declined during the 3-d period, insoluble 14 N remained relatively constant. In shoots both soluble organic 14 N and 14 NH 4 + declined, but a comparable increase in insoluble 14 N was noted. Thus, total 14 N in shoots remained constant, reflecting little or no net redistribution of 14 N between shoots and roots. Collectively, these observations reveal that catabolism of soluble organic N, not protein N, is the primary source of endogenous NH 4 + generation in maize roots. (author)

  19. Quantification of abscisic acid in a single maize root

    International Nuclear Information System (INIS)

    Reymond, P.; Saugy, M.; Pilet, P.E.

    1987-01-01

    Quantitative analyses of abscisic acid in the elongating zone of a single maize root (Zea mays L. cv LG 11) were performed by gas chromatography-mass spectrometry using negative chemical ion ionization. Data showed that the more abscisic acid, the slower the growth, but a large dispersion of individual values was observed. We assume that abscisic acid is perhaps not correlated only to the growth rate. (author)

  20. Simplified and representative bacterial community of maize roots.

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    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.

  1. RELATIONS AMONG WESTERN CORN ROOTWORM RESISTANCE TRAITS AND ELEMENTS CONCENTRATION IN MAIZE GERMPLASM ROOTS

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    Andrija Brkić

    2015-06-01

    Full Text Available Western corn rootworm – WCR (Diabrotica virgifera virgifera LeConte is an important maize pest in Croatia. Using native resistance of maize germplasm could reduce chemical treatments and other costs in maize production. Objectives of this study were: i to assess variability of WCR resistance traits (root injury, regrowth and size and concentrations of nine elements in roots of 128 maize genotypes, and ii to determine correlations among the traits and ion concentrations. Results revealed high variability of maize genotypes for both WCR resistance traits and ion concentrations. Significant moderate negative correlations (>-0.4 were detected between root injury and boron as well as between root regrowth and iron, manganese and zinc concentrations in root. Consequently, ion concentration in maize roots might have an impact on WCR resistance research.

  2. Root Ideotype Influences Nitrogen Transport and Assimilation in Maize

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    Julie Dechorgnat

    2018-04-01

    Full Text Available Maize (Zea mays, L. yield is strongly influenced by external nitrogen inputs and their availability in the soil solution. Overuse of nitrogen-fertilizers can have detrimental ecological consequences through increased nitrogen pollution of water and the release of the potent greenhouse gas, nitrous oxide. To improve yield and overall nitrogen use efficiency (NUE, a deeper understanding of nitrogen uptake and utilization is required. This study examines the performance of two contrasting maize inbred lines, B73 and F44. F44 was selected in Florida on predominantly sandy acidic soils subject to nitrate leaching while B73 was selected in Iowa on rich mollisol soils. Transcriptional, enzymatic and nitrogen transport analytical tools were used to identify differences in their N absorption and utilization capabilities. Our results show that B73 and F44 differ significantly in their genetic, enzymatic, and biochemical root nitrogen transport and assimilatory pathways. The phenotypes show a strong genetic relationship linked to nitrogen form, where B73 showed a greater capacity for ammonium transport and assimilation whereas F44 preferred nitrate. The contrasting phenotypes are typified by differences in root system architecture (RSA developed in the presence of both nitrate and ammonium. F44 crown roots were longer, had a higher surface area and volume with a greater lateral root number and density than B73. In contrast, B73 roots (primary, seminal, and crown were more abundant but lacked the defining features of the F44 crown roots. An F1 hybrid between B73 and F44 mirrored the B73 nitrogen specificity and root architecture phenotypes, indicating complete dominance of the B73 inbred. This study highlights the important link between RSA and nitrogen management and why both variables need to be tested together when defining NUE improvements in any selection program.

  3. Interspecies Interactions in Relation to Root Distribution Across the Rooting Profile in Wheat-Maize Intercropping Under Different Plant Densities

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    Yifan Wang

    2018-04-01

    Full Text Available In wheat-maize intercropping systems, the maize is often disadvantageous over the wheat during the co-growth period. It is unknown whether the impaired growth of maize can be recovered through the enhancement of the belowground interspecies interactions. In this study, we (i determined the mechanism of the belowground interaction in relation to root growth and distribution under different maize plant densities, and (ii quantified the “recovery effect” of maize after wheat harvest. The three-year (2014–2016 field experiment was conducted at the Oasis Agriculture Research Station of Gansu Agricultural University, Wuwei, Northwest China. Root weight density (RWD, root length density (RLD, and root surface area density (RSAD, were measured in single-cropped maize (M, single-cropped wheat (W, and three intercropping systems (i wheat-maize intercropping with no root barrier (i.e., complete belowground interaction, IC, (ii nylon mesh root barrier (partial belowground interaction, IC-PRI, and (iii plastic sheet root barrier (no belowground interaction, IC-NRI. The intercropped maize was planted at low (45,000 plants ha−1 and high (52,000 plants ha−1 densities. During the wheat/maize co-growth period, the IC treatment increased the RWD, RLD, and RSAD of the intercropped wheat in the 20–100 cm soil depth compared to the IC-PRI and IC-NRI systems; intercropped maize had 53% lower RWD, 81% lower RLD, and 70% lower RSAD than single-cropped maize. After wheat harvest, the intercropped maize recovered the growth with the increase of RWD by 40%, RLD by 44% and RSAD by 11%, compared to the single-cropped maize. Comparisons among the three intercropping systems revealed that the “recovery effect” of the intercropped maize was attributable to complete belowground interspecies interaction by 143%, the compensational effect due to root overlap by 35%, and the compensational effect due to water and nutrient exchange (CWN by 80%. The higher maize plant

  4. Cassava root meal as substitute for maize in layers ration

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    M Anaeto

    2011-06-01

    Full Text Available The effect of replacing maize with graded levels of cassava root meal (CRM as energy source in the diet of laying hens was evaluated during the eight weeks of feeding experiment on performance and cost benefits on layers. Forty-five Nera black laying hens of 24 weeks of age were allocated to five dietary treatments, with nine birds per treatment in a completely randomized design. CRM was used to formulate the diets at 0, 25, 50, 75, and 100%. The result showed that the feed intake of birds in the control group was significantly (p<0.05 different from those fed the CRM diets. The average weight gain of layers receiving up to 50% CRM was similar to the control birds, but significantly different from layers fed 75 and 100% CRM. No mortality was recorded. Egg production per hen per day and average egg weight were significantly different (p<0.05 for birds consuming more than 50% CRM in T4 and T5. Layer feed ration was made cheaper by the replacement of maize with cassava root meal in the diets.

  5. The mechanisms of root exudates of maize in improvement of iron nutrition of peanut in peanut/maize intercropping system by 14C tracer technique

    International Nuclear Information System (INIS)

    Zuo Yuanmei; Chen Qing; Zhang Fusuo

    2004-01-01

    The related mechanisms of root exudates of maize in improvement iron nutrition of peanut intercropped with maize was investigated by 14 C tracer technique. Neighboring roots between maize and peanut were separated by a 30 μm nylon net, the iron nutrition of peanut was also improved just like normal intercropping of maize and peanut. The results proved that root exudates of maize played an important role in improvement iron nutrition of peanut. The photosynthesis carbohydrate of maize could exuded into the rhizosphere of peanut and transfer into shoot and root of peanut in intercropping system. Root exudates of maize could increased efficiency of iron in soil and improved iron utilization of peanut

  6. Phosphate incorporation in organic compounds in roots of maize

    International Nuclear Information System (INIS)

    Michalik, I.; Ivanko, S.

    1976-01-01

    32 P incorporation and metabolism was investigated for short exposure times of 1 sec, 10 sec and 1, 10, 30 and 120 min. By stepwise extraction with a methanol-chloroform-formic acid-water mixture, various fractions of P compounds were obtained. Low-molecular acid-soluble P compounds were separated by one-dimensional paper chromatography. Of the total amount of 32 P absorbed by the roots of maize in the form of phosphate ions during the short incubation time of 1 sec, more than 33% was incorporated into organic compounds. With increasing incubation time, the proportion of 32 P in low-molecular organic compounds increased with the decreasing proportion of inorganic phosphorus. In the 1 sec, exposure incorporation was found in 3 low-molecular organic compounds only, namely ATP, ADP and diphosphoglyceric acid. The 32 P incorporation into ATP and ADP, in contrast with incorporation into diphosphoglyceric acid, increased markedly with increased exposure time. (author)

  7. The nitrate leached below maize root zone is available for deep-rooted wheat in winter wheat-summer maize rotation in the North China Plain

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Shunli [Key Laboratory of Crop Cultivation and Farming System, Ministry of Agriculture, College of Agronomy and Biotechnology, China Agricultural University, 2 West Yuanmingyuan Road, Beijing 100094 (China)], E-mail: zhoushl@cau.edu.cn; Wu Yongcheng [Key Laboratory of Crop Cultivation and Farming System, Ministry of Agriculture, College of Agronomy and Biotechnology, China Agricultural University, 2 West Yuanmingyuan Road, Beijing 100094 (China); College of Agronomy, Si Chuan Agricultural University, Yaan 625014 (China); Wang Zhimin [Key Laboratory of Crop Cultivation and Farming System, Ministry of Agriculture, College of Agronomy and Biotechnology, China Agricultural University, 2 West Yuanmingyuan Road, Beijing 100094 (China); Lu Laiqing; Wang Runzheng [Wuqiao Experimental Station, China Agricultural University, Hebei 061802 (China)

    2008-04-15

    In winter wheat (Triticum aestivum L.)-summer maize (Zea mays L.) rotation system in the North China Plain, maize roots do not extend beyond 1.2 m in the vertical soil profile, but wheat roots can reach up to 2.0 m. Increases in soil nitrate content at maize harvest and significant reductions after winter wheat harvest were observed in the 1.4-2.0 m depth under field conditions. The recovery of {sup 15}N isotope (calcium nitrate) from various (1.0, 1.2, 1.4, 1.6, 1.8 and 2.0 m) soil depths showed that deep-rooting winter wheat could use soil nitrate up to the 2.0 m depth. This accounted partially, for the reduced nitrate in the 1.4-2.0 m depth of the soil after harvest of wheat in the rotation system. - Deep-rooted wheat can recycle nitrate leached from maize root zone in winter wheat-summer maize rotation system.

  8. The nitrate leached below maize root zone is available for deep-rooted wheat in winter wheat-summer maize rotation in the North China Plain

    International Nuclear Information System (INIS)

    Zhou Shunli; Wu Yongcheng; Wang Zhimin; Lu Laiqing; Wang Runzheng

    2008-01-01

    In winter wheat (Triticum aestivum L.)-summer maize (Zea mays L.) rotation system in the North China Plain, maize roots do not extend beyond 1.2 m in the vertical soil profile, but wheat roots can reach up to 2.0 m. Increases in soil nitrate content at maize harvest and significant reductions after winter wheat harvest were observed in the 1.4-2.0 m depth under field conditions. The recovery of 15 N isotope (calcium nitrate) from various (1.0, 1.2, 1.4, 1.6, 1.8 and 2.0 m) soil depths showed that deep-rooting winter wheat could use soil nitrate up to the 2.0 m depth. This accounted partially, for the reduced nitrate in the 1.4-2.0 m depth of the soil after harvest of wheat in the rotation system. - Deep-rooted wheat can recycle nitrate leached from maize root zone in winter wheat-summer maize rotation system

  9. Maize ZmALMT2 is a root anion transporter that mediates constitutive root malate efflux.

    Science.gov (United States)

    Ligaba, Ayalew; Maron, Lyza; Shaff, Jon; Kochian, Leon; Piñeros, Miguel

    2012-07-01

    Root efflux of organic acid anions underlies a major mechanism of plant aluminium (Al) tolerance on acid soils. This efflux is mediated by transporters of the Al-activated malate transporter (ALMT) or the multi-drug and toxin extrusion (MATE) families. ZmALMT2 was previously suggested to be involved in Al tolerance based on joint association-linkage mapping for maize Al tolerance. In the current study, we functionally characterized ZmALMT2 by heterologously expressing it in Xenopus laevis oocytes and transgenic Arabidopsis. In oocytes, ZmALMT2 mediated an Al-independent electrogenic transport product of organic and inorganic anion efflux. Ectopic overexpression of ZmALMT2 in an Al-hypersensitive Arabidopsis KO/KD line lacking the Al tolerance genes, AtALMT1 and AtMATE, resulted in Al-independent constitutive root malate efflux which partially restored the Al tolerance phenotype. The lack of correlation between ZmALMT2 expression and Al tolerance (e.g., expression not localized to the root tip, not up-regulated by Al, and higher in sensitive versus tolerance maize lines) also led us to question ZmALMT2's role in Al tolerance. The functional properties of the ZmALMT2 transporter presented here, along with the gene expression data, suggest that ZmALMT2 is not involved in maize Al tolerance but, rather, may play a role in mineral nutrient acquisition and transport. Published 2011. This article is a U.S. Government work and is in the public domain in the USA.

  10. Effect of different irrigation systems on root growth of maize and cowpea plants in sandy soil

    Directory of Open Access Journals (Sweden)

    Noha A. Mahgoub

    2017-10-01

    Full Text Available A field experiment was conducted at the Experimental Farm, Faculty of Agriculture, Suez Canal University to study the influence of different irrigation systems on root length density and specific root length of maize and cowpea plants cultivated in sandy soil. Three irrigation systems (Surface, drip and sprinkler irrigation were used in this study. The NPK fertilizers were applied as recommended doses for maize and cowpea. Root samples were collected from the soil profile below one plant (maize and cowpea which was irrigated by the three irrigation systems by using an iron box (30 cm× 20 cm which is divided into 24 small boxes each box is (5× 5 × 5 cm. At surface irrigation, root length density of cowpea reached to soil depth 30-40cm with lateral distances 5-10 cm and 15-20 cm. Vertical distribution of root length density of maize was increased with soil depth till 20-25 cm, and then it decreased till soil depth 35-40cm. Under drip irrigation, root length density of cowpea increased horizontally from 0-5cm to 10-15cm then it decreased till soil depth 25-30 cm and below this depth root length density disappeared. For the root length density and specific root length of maize under drip irrigation, the data showed that root length density and specific root length decreased with increasing in soil depth. The root length density of cowpea under sprinkler irrigation at 0-5cm disappeared from horizontal distance at 25-30 cm. The data showed that root length density of maize under sprinkler irrigation was higher at the soil top layers 0-5 cm and 5-10 cm than other layers from 10-40 cm.

  11. Metabolic Response of Maize Roots to Hyperosmotic Shock 1

    Science.gov (United States)

    Spickett, Corinne M.; Smirnoff, Nicholas; Ratcliffe, R. George

    1992-01-01

    31P nuclear magnetic resonance spectroscopy was used to study the response of maize (Zea mays L.) root tips to hyperosmotic shock. The aim was to identify changes in metabolism that might be relevant to the perception of low soil water potential and the subsequent adaptation of the tissue to these conditions. Osmotic shock was found to result in two different types of response: changes in metabolite levels and changes in intracellular pH. The most notable metabolic changes, which were produced by all the osmotica tested, were increases in phosphocholine and vacuolar phosphate, with a transient increase in cytoplasmic phosphate. It was observed that treatment with ionic and nonionic osmotica produced different effects on the concentrations of bioenergetically important metabolites. It is postulated that these changes are the result of hydrolysis of phosphatidylcholine and other membrane phospholipids, due to differential activation of specific membrane-associated phospholipases by changes in the surface tension of the plasmalemma. These events may be important in the detection of osmotic shock and subsequent acclimatization. A cytoplasmic alkalinization was also observed during hyperosmotic treatment, and this response, which is consistent with the activation of the plasmalemma H+-ATPase, together with the other metabolic changes, may suggest the existence of a complex and integrated mechanism of osmoregulation. PMID:16669012

  12. Phosphate incorporation in organic compounds in roots of maize

    Energy Technology Data Exchange (ETDEWEB)

    Michalik, I; Ivanko, S [Vysoka Skola Polnohospodarska, Nitra (Czechoslovakia)

    1976-01-01

    /sup 32/P incorporation and metabolism was investigated for short exposure times of 1 sec, 10 sec and 1, 10, 30 and 120 min. By stepwise extraction with a methanol-chloroform-formic acid-water mixture, various fractions of P compounds were obtained. Low-molecular acid-soluble P compounds were separated by one-dimensional paper chromatography. Of the total amount of /sup 32/P absorbed by the roots of maize in the form of phosphate ions during the short incubation time of 1 sec, more than 33% was incorporated into organic compounds. With increasing incubation time, the proportion of /sup 32/P in low-molecular organic compounds increased with the decreasing proportion of inorganic phosphorus. In the 1 sec, exposure incorporation was found in 3 low-molecular organic compounds only, namely ATP, ADP and diphosphoglyceric acid. The /sup 32/P incorporation into ATP and ADP, in contrast with incorporation into diphosphoglyceric acid, increased markedly with increased exposure time.

  13. Root-type-specific plasticity in response to localized high nitrate supply in maize (Zea mays).

    Science.gov (United States)

    Yu, Peng; Hochholdinger, Frank; Li, Chunjian

    2015-10-01

    Shoot-borne roots contribute to most of the nutrient uptake throughout the life cycle of maize (Zea mays). Compared with numerous studies with embryonic roots, detailed information on the phenotypic plasticity of shoot-borne roots in response to a heterogeneous nitrogen supply is scarce. The present study therefore provides a comprehensive profile of fine-scale plastic responses of distinct root types to localized high nitrate supply. Seedlings of the maize inbred line B73 were grown in split-root systems. The anatomy and morphological plasticity of the primary root and the roots initiated from the 2nd, 5th and 7th shoot nodes, and their lateral roots, were studied in response to local high nitrate supply to one side of the root system. In contrast to the insensitivity of axial roots, local high nitrate supply increased the length of 1st-order lateral roots on the primary root and the three whorls of shoot-borne roots at different growth stages, and increased the density of 1st-order lateral roots on the 7th shoot-borne root after silking. The length and density of 2nd-order lateral roots on the three whorls of shoot-borne roots displayed a more flexible response to local high nitrate than 1st-order lateral roots. Root diameter and number, and total area and diameter of metaxylem vessels increased from the primary root to early and then later developed shoot-borne roots, which showed a positive relationship with shoot growth and N accumulation. Maize axial roots and lateral roots responded differently to local high nitrate, and this was related to their function. The extent of morphological plasticity of lateral roots in response to local high nitrate depended on the initiation time of the shoot-borne roots on which the lateral roots developed. Morphological plasticity was higher on 2nd-order than on 1st-order lateral roots. The results suggest that higher order lateral root branching might be a potential target for genetic improvement in future maize breeding.

  14. Auxins differentially regulate root system architecture and cell cycle protein levels in maize seedlings.

    Science.gov (United States)

    Martínez-de la Cruz, Enrique; García-Ramírez, Elpidio; Vázquez-Ramos, Jorge M; Reyes de la Cruz, Homero; López-Bucio, José

    2015-03-15

    Maize (Zea mays) root system architecture has a complex organization, with adventitious and lateral roots determining its overall absorptive capacity. To generate basic information about the earlier stages of root development, we compared the post-embryonic growth of maize seedlings germinated in water-embedded cotton beds with that of plants obtained from embryonic axes cultivated in liquid medium. In addition, the effect of four different auxins, namely indole-3-acetic acid (IAA), 1-naphthaleneacetic acid (NAA), indole-3-butyric acid (IBA) and 2,4-dichlorophenoxyacetic acid (2,4-D) on root architecture and levels of the heat shock protein HSP101 and the cell cycle proteins CKS1, CYCA1 and CDKA1 were analyzed. Our data show that during the first days after germination, maize seedlings develop several root types with a simultaneous and/or continuous growth. The post-embryonic root development started with the formation of the primary root (PR) and seminal scutellar roots (SSR) and then continued with the formation of adventitious crown roots (CR), brace roots (BR) and lateral roots (LR). Auxins affected root architecture in a dose-response fashion; whereas NAA and IBA mostly stimulated crown root formation, 2,4-D showed a strong repressing effect on growth. The levels of HSP101, CKS1, CYCA1 and CDKA in root and leaf tissues were differentially affected by auxins and interestingly, HSP101 registered an auxin-inducible and root specific expression pattern. Taken together, our results show the timing of early branching patterns of maize and indicate that auxins regulate root development likely through modulation of the HSP101 and cell cycle proteins. Copyright © 2014 Elsevier GmbH. All rights reserved.

  15. Transcriptome analysis of cadmium-treated roots in maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Runqing Yue

    2016-08-01

    Full Text Available Cadmium (Cd is a heavy metal and is highly toxic to all plant species. However, the underlying molecular mechanism controlling the effects of auxin on the Cd stress response in maize is largely unknown. In this study, the transcriptome produced by maize ‘Zheng 58’ root responses to Cd stress was sequenced using Illumina sequencing technology. In our study, six RNA-seq libraries yielded a total of 244 million clean short reads and 30.37 Gb of sequence data. A total of 6342 differentially expressed genes (DEGs were grouped into 908 Gene Ontology (GO categories and 198 Kyoto Encyclopedia of Genes and Genomes terms. GO term enrichment analysis indicated that various auxin signaling pathway-related GO terms were significantly enriched in DEGs. Comparison of the transcript abundances for auxin biosynthesis, transport, and downstream response genes revealed a universal expression response under Cd treatment. Furthermore, our data showed that free indole-3-acetic acid (IAA levels were significantly reduced; but IAA oxidase activity was up-regulated after Cd treatment in maize roots. The analysis of Cd activity in maize roots under different Cd and auxin conditions confirmed that auxin affected Cd accumulation in maize seedlings. These results will improve our understanding of the complex molecular mechanisms underlying the response to Cd stress in maize roots.

  16. The Effects of Two Different Deficit Irrigation Managements on the Root Length of Maize

    Directory of Open Access Journals (Sweden)

    M. Gheysari

    2015-06-01

    Full Text Available The response of root to water stress is one of the most important parameters for researchers. Study of growth and distribution of root under different irrigation managements helpsresearchersto a better understanding of soil water content, and the availability of water and nutrition in water stress condition. To investigate the effects of four levels of irrigation under two different deficit irrigation managements on the root length of maize, a study was conducted in 2009. Irrigation managements included fixed irrigation interval-variable irrigation depth (M1 and variable irrigation interval-fixed irrigation depth (M2. Maize plants were planted in 120 large 110-liter containers in a strip-plot design in a randomized complete block with three replications. Root data sampling was done after root washing in five growth stages. The results showed that the effect of irrigation levels on root length was significant (P

  17. Effect of planting density on root lodging resistance and its relationship to nodal root growth characteristics in maize (Zea mays L.)

    DEFF Research Database (Denmark)

    Liu, Shengqun; Song, Fengbin; Liu, Fulai

    2012-01-01

    Increase of planting density has been widely used to increase grain yield in maize. However, it may lead to higher risk of root lodging hence causing significant yield loss of the crop. The objective of this study was to investigate the effect of planting density on maize nodal root growth...

  18. 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.

  19. Benzoxazinoids in root exudates of maize attract Pseudomonas putida to the rhizosphere.

    Directory of Open Access Journals (Sweden)

    Andrew L Neal

    Full Text Available Benzoxazinoids, such as 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H-one (DIMBOA, are secondary metabolites in grasses. In addition to their function in plant defence against pests and diseases above-ground, benzoxazinoids (BXs have also been implicated in defence below-ground, where they can exert allelochemical or antimicrobial activities. We have studied the impact of BXs on the interaction between maize and Pseudomonas putida KT2440, a competitive coloniser of the maize rhizosphere with plant-beneficial traits. Chromatographic analyses revealed that DIMBOA is the main BX compound in root exudates of maize. In vitro analysis of DIMBOA stability indicated that KT2440 tolerance of DIMBOA is based on metabolism-dependent breakdown of this BX compound. Transcriptome analysis of DIMBOA-exposed P. putida identified increased transcription of genes controlling benzoate catabolism and chemotaxis. Chemotaxis assays confirmed motility of P. putida towards DIMBOA. Moreover, colonisation essays in soil with Green Fluorescent Protein (GFP-expressing P. putida showed that DIMBOA-producing roots of wild-type maize attract significantly higher numbers of P. putida cells than roots of the DIMBOA-deficient bx1 mutant. Our results demonstrate a central role for DIMBOA as a below-ground semiochemical for recruitment of plant-beneficial rhizobacteria during the relatively young and vulnerable growth stages of maize.

  20. 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.

  1. Transcriptomic and anatomical complexity of primary, seminal, and crown roots highlight root type-specific functional diversity in maize (Zea mays L.).

    Science.gov (United States)

    Tai, Huanhuan; Lu, Xin; Opitz, Nina; Marcon, Caroline; Paschold, Anja; Lithio, Andrew; Nettleton, Dan; Hochholdinger, Frank

    2016-02-01

    Maize develops a complex root system composed of embryonic and post-embryonic roots. Spatio-temporal differences in the formation of these root types imply specific functions during maize development. A comparative transcriptomic study of embryonic primary and seminal, and post-embryonic crown roots of the maize inbred line B73 by RNA sequencing along with anatomical studies were conducted early in development. Seminal roots displayed unique anatomical features, whereas the organization of primary and crown roots was similar. For instance, seminal roots displayed fewer cortical cell files and their stele contained more meta-xylem vessels. Global expression profiling revealed diverse patterns of gene activity across all root types and highlighted the unique transcriptome of seminal roots. While functions in cell remodeling and cell wall formation were prominent in primary and crown roots, stress-related genes and transcriptional regulators were over-represented in seminal roots, suggesting functional specialization of the different root types. Dynamic expression of lignin biosynthesis genes and histochemical staining suggested diversification of cell wall lignification among the three root types. Our findings highlight a cost-efficient anatomical structure and a unique expression profile of seminal roots of the maize inbred line B73 different from primary and crown roots. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  2. Root inoculation with Pseudomonas putida KT2440 induces transcriptional and metabolic changes and systemic resistance in maize plants

    Directory of Open Access Journals (Sweden)

    Chantal ePlanchamp

    2015-01-01

    Full Text Available Pseudomonas putida KT2440 (KT2440 rhizobacteria colonize a wide range of plants. They have been extensively studied for their capacity to adhere to maize seeds, to tolerate toxic secondary metabolites produced by maize roots and to be attracted by maize roots. However, the response of maize plants to KT2440 colonization has not been investigated yet. Maize roots were inoculated with KT2440 and the local (roots and systemic (leaves early plant responses were investigated. The colonization behavior of KT2440 following application to maize seedlings was investigated and transcriptional analysis of stress- and defense-related genes as well as metabolite profiling of local and systemic maize tissues of KT2440-inoculated were performed. The local and systemic responses differed and more pronounced changes were observed in roots compared to leaves. Early in the interaction roots responded via jasmonic acid- and abscisic acid-dependent signaling. Interestingly, during later steps, the salicylic acid pathway was suppressed. Metabolite profiling revealed the importance of plant phospholipids in KT2440-maize interactions. An additional important maize secondary metabolite, a form of benzoxazinone, was also found to be differently abundant in roots three days after KT2440 inoculation. However, the transcriptional and metabolic changes observed in bacterized plants early during the interaction were minor and became even less pronounced with time, indicating an accommodation state of the plant to the presence of KT2440. Since the maize plants reacted to the presence of KT2440 in the rhizosphere, we also investigated the ability of these bacteria to trigger induced systemic resistance (ISR against the maize anthracnose fungus Colletotrichum graminicola. The observed resistance was expressed as strongly reduced leaf necrosis and fungal development in infected bacterized plants compared to non-bacterized controls, showing the potential of KT2440 to act as

  3. Zinc oxide nanoparticle exposure triggers different gene expression patterns in maize shoots and roots

    International Nuclear Information System (INIS)

    Xun, Hongwei; Ma, Xintong; Chen, Jing; Yang, Zhongzhou; Liu, Bao; Gao, Xiang; Li, Guo; Yu, Jiamiao; Wang, Li; Pang, Jinsong

    2017-01-01

    The potential impacts of environmentally accumulated zinc oxide nanoparticles (nZnOs) on plant growth have not been well studied. A transcriptome profile analysis of maize exposed to nZnOs showed that the genes in the shoots and roots responded differently. Although the number of differentially expressed genes (DEGs) in the roots was greater than that in the shoots, the number of up- or down-regulated genes in both the shoots and roots was similar. The enrichment of gene ontology (GO) terms was also significantly different in the shoots and roots. The “nitrogen compound metabolism” and “cellular component” terms were specifically and highly up-regulated in the nZnO-exposed roots, whereas the categories “cellular metabolic process”, “primary metabolic process” and “secondary metabolic process” were down-regulated in the exposed roots only. Our results revealed the DEG response patterns in maize shoots and roots after nZnO exposure. - Highlights: • The gene expression patterns of maize exposed to ZnO nanoparticles (nZnO) varied in the shoots and roots. • A majority of the differentially expressed genes induced by nZnO exposure were exclusive to either the shoots or roots. • A similar number of up- and down-regulated genes was observed in the exposed shoots. • More up-regulated than down-regulated genes were found in the exposed roots. • A greater number of GO processes were observed in the nZnO exposed maize roots than in the exposed shoots. • GO terms in the “nitrogen compound metabolic process” category were exclusively and highly expressed in the exposed roots. • GO terms in the “nutrient reservoir” category were exclusively and highly expressed in the exposed roots. • Term “small molecule metabolic process” was also exclusively up-regulated in the exposed roots. • Processes in “cellular metabolic”, “primary metabolic” and “secondary metabolic” were down-regulated in the exposed roots.

  4. Transcriptomic profiling of Bacillus amyloliquefaciens FZB42 in response to maize root exudates

    LENUS (Irish Health Repository)

    Fan, Ben

    2012-06-21

    AbstractBackgroundPlant root exudates have been shown to play an important role in mediating interactions between plant growth-promoting rhizobacteria (PGPR) and their host plants. Most investigations were performed on Gram-negative rhizobacteria, while much less is known about Gram-positive rhizobacteria. To elucidate early responses of PGPR to root exudates, we investigated changes in the transcriptome of a Gram-positive PGPR to plant root exudates.ResultsBacillus amyloliquefaciens FZB42 is a well-studied Gram-positive PGPR. To obtain a comprehensive overview of FZB42 gene expression in response to maize root exudates, microarray experiments were performed. A total of 302 genes representing 8.2% of the FZB42 transcriptome showed significantly altered expression levels in the presence of root exudates. The majority of the genes (261) was up-regulated after incubation of FZB42 with root exudates, whereas only 41 genes were down-regulated. Several groups of the genes which were strongly induced by the root exudates are involved in metabolic pathways relating to nutrient utilization, bacterial chemotaxis and motility, and non-ribosomal synthesis of antimicrobial peptides and polyketides.ConclusionsHere we present a transcriptome analysis of the root-colonizing bacterium Bacillus amyloliquefaciens FZB42 in response to maize root exudates. The 302 genes identified as being differentially transcribed are proposed to be involved in interactions of Gram-positive bacteria with plants.

  5. Is the inherent potential of maize roots efficient for soil phosphorus acquisition?

    Science.gov (United States)

    Deng, Yan; Chen, Keru; Teng, Wan; Zhan, Ai; Tong, Yiping; Feng, Gu; Cui, Zhenling; Zhang, Fusuo; Chen, Xinping

    2014-01-01

    Sustainable agriculture requires improved phosphorus (P) management to reduce the overreliance on P fertilization. Despite intensive research of root adaptive mechanisms for improving P acquisition, the inherent potential of roots for efficient P acquisition remains unfulfilled, especially in intensive agriculture, while current P management generally focuses on agronomic and environmental concerns. Here, we investigated how levels of soil P affect the inherent potential of maize (Zea mays L.) roots to obtain P from soil. Responses of root morphology, arbuscular mycorrhizal colonization, and phosphate transporters were characterized and related to agronomic traits in pot and field experiments with soil P supply from deficiency to excess. Critical soil Olsen-P level for maize growth approximated 3.2 mg kg(-1), and the threshold indicating a significant environmental risk was about 15 mg kg(-1), which represented the lower and upper levels of soil P recommended in current P management. However, most root adaptations involved with P acquisition were triggered when soil Olsen-P was below 10 mg kg(-1), indicating a threshold for maximum root inherent potential. Therefore, to maintain efficient inherent potential of roots for P acquisition, we suggest that the target upper level of soil P in intensive agriculture should be reduced from the environmental risk threshold to the point maximizing the inherent potential of roots.

  6. Is the inherent potential of maize roots efficient for soil phosphorus acquisition?

    Directory of Open Access Journals (Sweden)

    Yan Deng

    Full Text Available Sustainable agriculture requires improved phosphorus (P management to reduce the overreliance on P fertilization. Despite intensive research of root adaptive mechanisms for improving P acquisition, the inherent potential of roots for efficient P acquisition remains unfulfilled, especially in intensive agriculture, while current P management generally focuses on agronomic and environmental concerns. Here, we investigated how levels of soil P affect the inherent potential of maize (Zea mays L. roots to obtain P from soil. Responses of root morphology, arbuscular mycorrhizal colonization, and phosphate transporters were characterized and related to agronomic traits in pot and field experiments with soil P supply from deficiency to excess. Critical soil Olsen-P level for maize growth approximated 3.2 mg kg(-1, and the threshold indicating a significant environmental risk was about 15 mg kg(-1, which represented the lower and upper levels of soil P recommended in current P management. However, most root adaptations involved with P acquisition were triggered when soil Olsen-P was below 10 mg kg(-1, indicating a threshold for maximum root inherent potential. Therefore, to maintain efficient inherent potential of roots for P acquisition, we suggest that the target upper level of soil P in intensive agriculture should be reduced from the environmental risk threshold to the point maximizing the inherent potential of roots.

  7. Early colonization pattern of maize (Zea mays L. Poales, Poaceae roots by Herbaspirillum seropedicae (Burkholderiales, Oxalobacteraceae

    Directory of Open Access Journals (Sweden)

    Rose A. Monteiro

    2008-12-01

    Full Text Available The bacterium Herbaspirillum seropedicae is an endophytic diazotroph found in several plants, including economically important poaceous species. However, the mechanisms involved in the interaction between H. seropedicae and these plants are not completely characterized. We investigated the attachment of Herbaspirillum to maize roots and the invasion of the roots by this bacterium using H. seropedicae strain SMR1 transformed with the suicide plasmid pUTKandsRed, which carries a mini-Tn5 transposon containing the gene for the Discosoma red fluorescent protein (Dsred constitutively expressed together with the kanamycin resistance gene. Integration of the mini-Tn5 into the bacterial chromosome yielded the mutant H. seropedicae strain RAM4 which was capable of expressing Dsred and could be observed on and inside fresh maize root samples. Confocal microscopy of maize roots inoculated with H. seropedicae three days after germination showed that H. seropedicae cell were attached to the root surface 30 min after inoculation, were visible in the internal tissues after twenty-four hours and in the endodermis, the central cylinder and xylem after three days.

  8. Maize root culture as a model system for studying azoxystrobin biotransformation in plants

    DEFF Research Database (Denmark)

    Gautam, Maheswor; Elhiti, Mohamed Abdelsamad A; Fomsgaard, Inge S.

    2018-01-01

    Hairy roots induced by Agrobacterium rhizogenes are well established models to study the metabolism of xenobiotics in plants for phytoremediation purposes. However, the model requires special skills and resources for growing and is a time-consuming process. The roots induction process alters...... the genetic construct of a plant and is known to express genes that are normally absent from the non-transgenic plants. In this study, we propose and establish a non-transgenic maize root model to study xenobiotic metabolism in plants for phytoremediation purpose using azoxystrobin as a xenobiotic compound...

  9. 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...

  10. Spatial rooting patterns of gliricidia, pigeon pea and maize intercrops and effect on profile soil N and P distribution in southern Malawi

    NARCIS (Netherlands)

    Makumba, W.; Akinnifesi, F.K.; Janssen, B.H.

    2009-01-01

    The concept of competition or complementarity between tree and crop roots for below ground resources have been a major debate in simultaneous systems. Root studies were conducted in three cropping systems, namely: sole maize, pigeon pea/maize intercropping and Gliricidia sepium (Gliricidia)/maize

  11. Zinc oxide nanoparticle exposure triggers different gene expression patterns in maize shoots and roots.

    Science.gov (United States)

    Xun, Hongwei; Ma, Xintong; Chen, Jing; Yang, Zhongzhou; Liu, Bao; Gao, Xiang; Li, Guo; Yu, Jiamiao; Wang, Li; Pang, Jinsong

    2017-10-01

    The potential impacts of environmentally accumulated zinc oxide nanoparticles (nZnOs) on plant growth have not been well studied. A transcriptome profile analysis of maize exposed to nZnOs showed that the genes in the shoots and roots responded differently. Although the number of differentially expressed genes (DEGs) in the roots was greater than that in the shoots, the number of up- or down-regulated genes in both the shoots and roots was similar. The enrichment of gene ontology (GO) terms was also significantly different in the shoots and roots. The "nitrogen compound metabolism" and "cellular component" terms were specifically and highly up-regulated in the nZnO-exposed roots, whereas the categories "cellular metabolic process", "primary metabolic process" and "secondary metabolic process" were down-regulated in the exposed roots only. Our results revealed the DEG response patterns in maize shoots and roots after nZnO exposure. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Maize root lectins mediate the interaction with Herbaspirillum seropedicae via N-acetyl glucosamine residues of lipopolysaccharides.

    Directory of Open Access Journals (Sweden)

    Eduardo Balsanelli

    Full Text Available Herbaspirillum seropedicae is a plant growth-promoting diazotrophic betaproteobacterium which associates with important crops, such as maize, wheat, rice and sugar-cane. We have previously reported that intact lipopolysaccharide (LPS is required for H. seropedicae attachment and endophytic colonization of maize roots. In this study, we present evidence that the LPS biosynthesis gene waaL (codes for the O-antigen ligase is induced during rhizosphere colonization by H. seropedicae. Furthermore a waaL mutant strain lacking the O-antigen portion of the LPS is severely impaired in colonization. Since N-acetyl glucosamine inhibits H. seropedicae attachment to maize roots, lectin-like proteins from maize roots (MRLs were isolated and mass spectrometry (MS analysis showed that MRL-1 and MRL-2 correspond to maize proteins with a jacalin-like lectin domain, while MRL-3 contains a B-chain lectin domain. These proteins showed agglutination activity against wild type H. seropedicae, but failed to agglutinate the waaL mutant strain. The agglutination reaction was severely diminished in the presence of N-acetyl glucosamine. Moreover addition of the MRL proteins as competitors in H. seropedicae attachment assays decreased 80-fold the adhesion of the wild type to maize roots. The results suggest that N-acetyl glucosamine residues of the LPS O-antigen bind to maize root lectins, an essential step for efficient bacterial attachment and colonization.

  13. Maize root lectins mediate the interaction with Herbaspirillum seropedicae via N-acetyl glucosamine residues of lipopolysaccharides.

    Science.gov (United States)

    Balsanelli, Eduardo; Tuleski, Thalita Regina; de Baura, Valter Antonio; Yates, Marshall Geoffrey; Chubatsu, Leda Satie; Pedrosa, Fabio de Oliveira; de Souza, Emanuel Maltempi; Monteiro, Rose Adele

    2013-01-01

    Herbaspirillum seropedicae is a plant growth-promoting diazotrophic betaproteobacterium which associates with important crops, such as maize, wheat, rice and sugar-cane. We have previously reported that intact lipopolysaccharide (LPS) is required for H. seropedicae attachment and endophytic colonization of maize roots. In this study, we present evidence that the LPS biosynthesis gene waaL (codes for the O-antigen ligase) is induced during rhizosphere colonization by H. seropedicae. Furthermore a waaL mutant strain lacking the O-antigen portion of the LPS is severely impaired in colonization. Since N-acetyl glucosamine inhibits H. seropedicae attachment to maize roots, lectin-like proteins from maize roots (MRLs) were isolated and mass spectrometry (MS) analysis showed that MRL-1 and MRL-2 correspond to maize proteins with a jacalin-like lectin domain, while MRL-3 contains a B-chain lectin domain. These proteins showed agglutination activity against wild type H. seropedicae, but failed to agglutinate the waaL mutant strain. The agglutination reaction was severely diminished in the presence of N-acetyl glucosamine. Moreover addition of the MRL proteins as competitors in H. seropedicae attachment assays decreased 80-fold the adhesion of the wild type to maize roots. The results suggest that N-acetyl glucosamine residues of the LPS O-antigen bind to maize root lectins, an essential step for efficient bacterial attachment and colonization.

  14. Toxic effects of boron on growth and antioxidant system parameters of maize (Zea mays L.) roots.

    Science.gov (United States)

    Esim, Nevzat; Tiryaki, Deniz; Karadagoglu, Omer; Atici, Okkes

    2013-10-01

    The aim of this study was to investigate the possible oxidative stress and the antioxidant response, which were caused on maize by boron (B). For this, 11- and 15-day-old maize seedlings were subjected to 2 or 4 mM B in the form of boric acid (H₃BO₃) for 2 and/or 6 days. At the end of the treatment period, root length, hydrogen peroxide (H₂O₂) content, malondialdehyde (MDA) content and the antioxidant enzymes superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT) were measured. The results revealed that root length of plants, activity of antioxidative enzymes such as SOD, POX and CAT and also H₂O₂ contents and MDA levels were seriously affected by excess B. These results suggested that the oxidative stress occurred due to the toxic effect of B.

  15. Extensive tissue-specific transcriptomic plasticity in maize primary roots upon water deficit

    OpenAIRE

    Opitz, Nina; Marcon, Caroline; Paschold, Anja; Malik, Waqas Ahmed; Lithio, Andrew; Brandt, Ronny; Piepho, Hans-Peter; Nettleton, Dan; Hochholdinger, Frank

    2015-01-01

    Water deficit is the most important environmental constraint severely limiting global crop growth and productivity. This study investigated early transcriptome changes in maize (Zea mays L.) primary root tissues in response to moderate water deficit conditions by RNA-Sequencing. Differential gene expression analyses revealed a high degree of plasticity of the water deficit response. The activity status of genes (active/inactive) was determined by a Bayesian hierarchical model. In total, 70% o...

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

    Science.gov (United States)

    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. Nitrate-induced changes in protein synthesis and translation of RNA in maize roots

    International Nuclear Information System (INIS)

    McClure, P.R.; Omholt, T.E.; Pace, G.M.; Bouthyette, P.Y.

    1987-01-01

    Nitrate regulation of protein synthesis and RNA translation in maize (Zea mays L. var B73) roots was examined, using in vivo labeling with [ 35 S]methionine and in vitro translation. Nitrate enhanced the synthesis of a 31 kilodalton membrane polypeptide which was localized in a fraction enriched in tonoplast and/or endoplasmic reticulum membrane vesicles. The nitrate-enhanced synthesis was correlated with an acceleration of net nitrate uptake by seedlings during initial exposure to nitrate. Nitrate did not consistently enhance protein synthesis in other membrane fractions. Synthesis of up to four soluble polypeptides (21, 40, 90, and 168 kilodaltons) was also enhanced by nitrate. The most consistent enhancement was that of the 40 kilodalton polypeptide. No consistent nitrate-induced changes were noted in the organellar fraction (14,000g pellet of root homogenates). When roots were treated with nitrate, the amount of [ 35 S]methionine increased in six in vitro translation products (21, 24, 41, 56, 66, and 90 kilodaltons). Nitrate treatment did not enhance accumulation of label in translation products with a molecular weight of 31,000 (corresponding to the identified nitrate-inducible membrane polypeptide). Incubation of in vitro translation products with root membranes caused changes in the SDS-PAGE profiles in the vecinity of 31 kilodaltons. The results suggest that the nitrate-inducible, 31 kilodalton polypeptide from a fraction enriched in tonoplast and/or endoplasmic reticulum may be involved in regulating nitrate accumulation by maize roots

  18. Studies on the secretion of maize root-cap slime. Pt. 3

    International Nuclear Information System (INIS)

    Paull, R.E.; Jones, R.L.

    1975-01-01

    Autoradiography was used to localize the sites of incorporation of L-[ 3 H]fucose into root tips of maize (Zea mays L. cv. S.X. 17). By light microscopy, accumulation of label from [ 3 H]fucose could be seen in the peripheral cells of the root cap. Extraction of sections prepared by freeze-substitution showed that most of the label in the cytoplasm of peripheral root-cap cells is water-soluble whereas label associated with the wall is sodium-hydroxide-soluble. In the electron microscope, glutaraldehyde-fixed peripheral cells of maize root caps are characterized by the presence of numerous dictyosomes and vesicles. The distended dictyosome cisternae and vesicles have large deposits of silver after staining with periodic acid-silver methanamine. An accumulation of material similar to that found in dictyosomes and vesicles is observed between the cell membrane and wall in glutaraldehyde-formaldehyde-fixed tissue. At the electron-microscope level label in peripheral root cap cells incubated in [ 3 H]fucose for periods from 10 to 120 min was found primarily over dictyosomes and vesicles. In pulse-chase experiments label was chased from the diclyosomes and vesicles to the exterior of the cell in 20-30 min. Less than 19% of the label in pulse-chase experiments was associated with organelles other than dictyosomes vesicles. (orig.) [de

  19. Induction of nitrate transport in maize roots, and kinetics of influx, measured with nitrogen-13

    International Nuclear Information System (INIS)

    Hole, D.J.; Drew, M.C.; Emran, A.M.; Fares, Y.

    1990-01-01

    Unlike phosphate or potassium transport, uptake of nitrate by roots is induced, in part, by contact with the substrate ion. Plasmalemma influx of 13 N-labeled nitrate in maize roots was studied in relation to induction of the uptake system, and the influence of short-term N starvation. Maize (Zea mays) roots not previously exposed to nitrate had a constitutive transport system (state 1), but influx increased 250% during six hours of contact with 100 micromolar nitrate, by which time the transport mechanism appeared to be fully synthesized (state 2). A three-day period of N starvation prior to induction and measurement of nitrate influx resulted in a greater capacity to transport nitrate than in unstarved controls, but this was fully expressed only if roots were kept in contact with nitrate for the six hours needed for full induction (state 2E). A kinetic analysis indicated a 160% increase in maximum influx in N-starved, induced roots with a small decrease in K m . The inducible component to nitrate influx was induced only by contact with nitrate. Full expression of the nitrate inducible transport system was dependent upon mRNA synthesis. An inhibitor of cytoplasmic protein synthesis (cycloheximide) eliminated the formation of the transport system while inhibition by chloramphenicol of mitochondrial- or plastid-coded protein synthesis had no effect. Poisoning of membrane-bound proteins effectively disabled both the constitutive and induced transport systems

  20. Extensive tissue-specific transcriptomic plasticity in maize primary roots upon water deficit.

    Science.gov (United States)

    Opitz, Nina; Marcon, Caroline; Paschold, Anja; Malik, Waqas Ahmed; Lithio, Andrew; Brandt, Ronny; Piepho, Hans-Peter; Nettleton, Dan; Hochholdinger, Frank

    2016-02-01

    Water deficit is the most important environmental constraint severely limiting global crop growth and productivity. This study investigated early transcriptome changes in maize (Zea mays L.) primary root tissues in response to moderate water deficit conditions by RNA-Sequencing. Differential gene expression analyses revealed a high degree of plasticity of the water deficit response. The activity status of genes (active/inactive) was determined by a Bayesian hierarchical model. In total, 70% of expressed genes were constitutively active in all tissues. In contrast, deficit-responsive genes (1915) were consistently regulated in all tissues, while >75% (1501 genes) were specifically regulated in a single root tissue. Water deficit-responsive genes were most numerous in the cortex of the mature root zone and in the elongation zone. The most prominent functional categories among differentially expressed genes in all tissues were 'transcriptional regulation' and 'hormone metabolism', indicating global reprogramming of cellular metabolism as an adaptation to water deficit. Additionally, the most significant transcriptomic changes in the root tip were associated with cell wall reorganization, leading to continued root growth despite water deficit conditions. This study provides insight into tissue-specific water deficit responses and will be a resource for future genetic analyses and breeding strategies to develop more drought-tolerant maize cultivars. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  1. Transcriptomic response of maize primary roots to low temperatures at seedling emergence.

    Science.gov (United States)

    Di Fenza, Mauro; Hogg, Bridget; Grant, Jim; Barth, Susanne

    2017-01-01

    Maize ( Zea mays ) is a C 4 tropical cereal and its adaptation to temperate climates can be problematic due to low soil temperatures at early stages of establishment. In the current study we have firstly investigated the physiological response of twelve maize varieties, from a chilling condition adapted gene pool, to sub-optimal growth temperature during seedling emergence. To identify transcriptomic markers of cold tolerance in already adapted maize genotypes, temperature conditions were set below the optimal growth range in both control and low temperature groups. The conditions were as follows; control (18 °C for 16 h and 12 °C for 8 h) and low temperature (12 °C for 16 h and 6 °C for 8 h). Four genotypes were identified from the condition adapted gene pool with significant contrasting chilling tolerance. Picker and PR39B29 were the more cold-tolerant lines and Fergus and Codisco were the less cold-tolerant lines. These four varieties were subjected to microarray analysis to identify differentially expressed genes under chilling conditions. Exposure to low temperature during establishment in the maize varieties Picker, PR39B29, Fergus and Codisco, was reflected at the transcriptomic level in the varieties Picker and PR39B29. No significant changes in expression were observed in Fergus and Codisco following chilling stress. A total number of 64 genes were differentially expressed in the two chilling tolerant varieties. These two varieties exhibited contrasting transcriptomic profiles, in which only four genes overlapped. We observed that maize varieties possessing an enhanced root growth ratio under low temperature were more tolerant, which could be an early and inexpensive measure for germplasm screening under controlled conditions. We have identified novel cold inducible genes in an already adapted maize breeding gene pool. This illustrates that further varietal selection for enhanced chilling tolerance is possible in an already preselected gene pool.

  2. Transcriptomic response of maize primary roots to low temperatures at seedling emergence

    Directory of Open Access Journals (Sweden)

    Mauro Di Fenza

    2017-01-01

    Full Text Available Background Maize (Zea mays is a C4 tropical cereal and its adaptation to temperate climates can be problematic due to low soil temperatures at early stages of establishment. Methods In the current study we have firstly investigated the physiological response of twelve maize varieties, from a chilling condition adapted gene pool, to sub-optimal growth temperature during seedling emergence. To identify transcriptomic markers of cold tolerance in already adapted maize genotypes, temperature conditions were set below the optimal growth range in both control and low temperature groups. The conditions were as follows; control (18 °C for 16 h and 12 °C for 8 h and low temperature (12 °C for 16 h and 6 °C for 8 h. Four genotypes were identified from the condition adapted gene pool with significant contrasting chilling tolerance. Results Picker and PR39B29 were the more cold-tolerant lines and Fergus and Codisco were the less cold-tolerant lines. These four varieties were subjected to microarray analysis to identify differentially expressed genes under chilling conditions. Exposure to low temperature during establishment in the maize varieties Picker, PR39B29, Fergus and Codisco, was reflected at the transcriptomic level in the varieties Picker and PR39B29. No significant changes in expression were observed in Fergus and Codisco following chilling stress. A total number of 64 genes were differentially expressed in the two chilling tolerant varieties. These two varieties exhibited contrasting transcriptomic profiles, in which only four genes overlapped. Discussion We observed that maize varieties possessing an enhanced root growth ratio under low temperature were more tolerant, which could be an early and inexpensive measure for germplasm screening under controlled conditions. We have identified novel cold inducible genes in an already adapted maize breeding gene pool. This illustrates that further varietal selection for enhanced chilling

  3. Lateral root development in the maize (Zea mays) lateral rootless1 mutant.

    Science.gov (United States)

    Husakova, Eva; Hochholdinger, Frank; Soukup, Ales

    2013-07-01

    The maize lrt1 (lateral rootless1) mutant is impaired in its development of lateral roots during early post-embryonic development. The aim of this study was to characterize, in detail, the influences that the mutation exerts on lateral root initiation and the subsequent developments, as well as to describe the behaviour of the entire plant under variable environmental conditions. Mutant lrt1 plants were cultivated under different conditions of hydroponics, and in between sheets of moist paper. Cleared whole mounts and anatomical sections were used in combination with both selected staining procedures and histochemical tests to follow root development. Root surface permeability tests and the biochemical quantification of lignin were performed to complement the structural data. The data presented suggest a redefinition of lrt1 function in lateral roots as a promoter of later development; however, neither the complete absence of lateral roots nor the frequency of their initiation is linked to lrt1 function. The developmental effects of lrt1 are under strong environmental influences. Mutant primordia are affected in structure, growth and emergence; and the majority of primordia terminate their growth during this last step, or shortly thereafter. The lateral roots are impaired in the maintenance of the root apical meristem. The primary root shows disturbances in the organization of both epidermal and subepidermal layers. The lrt1-related cell-wall modifications include: lignification in peripheral layers, the deposition of polyphenolic substances and a higher activity of peroxidase. The present study provides novel insights into the function of the lrt1 gene in root system development. The lrt1 gene participates in the spatial distribution of initiation, but not in its frequency. Later, the development of lateral roots is strongly affected. The effect of the lrt1 mutation is not as obvious in the primary root, with no influences observed on the root apical meristem

  4. Lateral root development in the maize (Zea mays) lateral rootless1 mutant

    Science.gov (United States)

    Husakova, Eva; Hochholdinger, Frank; Soukup, Ales

    2013-01-01

    Background and Aims The maize lrt1 (lateral rootless1) mutant is impaired in its development of lateral roots during early post-embryonic development. The aim of this study was to characterize, in detail, the influences that the mutation exerts on lateral root initiation and the subsequent developments, as well as to describe the behaviour of the entire plant under variable environmental conditions. Methods Mutant lrt1 plants were cultivated under different conditions of hydroponics, and in between sheets of moist paper. Cleared whole mounts and anatomical sections were used in combination with both selected staining procedures and histochemical tests to follow root development. Root surface permeability tests and the biochemical quantification of lignin were performed to complement the structural data. Key Results The data presented suggest a redefinition of lrt1 function in lateral roots as a promoter of later development; however, neither the complete absence of lateral roots nor the frequency of their initiation is linked to lrt1 function. The developmental effects of lrt1 are under strong environmental influences. Mutant primordia are affected in structure, growth and emergence; and the majority of primordia terminate their growth during this last step, or shortly thereafter. The lateral roots are impaired in the maintenance of the root apical meristem. The primary root shows disturbances in the organization of both epidermal and subepidermal layers. The lrt1-related cell-wall modifications include: lignification in peripheral layers, the deposition of polyphenolic substances and a higher activity of peroxidase. Conclusions The present study provides novel insights into the function of the lrt1 gene in root system development. The lrt1 gene participates in the spatial distribution of initiation, but not in its frequency. Later, the development of lateral roots is strongly affected. The effect of the lrt1 mutation is not as obvious in the primary root, with no

  5. Modification of antioxidant systems in cell walls of maize roots by different nitrogen sources

    International Nuclear Information System (INIS)

    Hadži-Tašković Šukalović V; Vuletić, M.; Marković, K.; Željko, Vučinić; Kravić, N.

    2016-01-01

    Antioxidant systems of maize root cell walls grown on different nitrogen sources were evaluated. Plants were grown on a medium containing only NO3- or the mixture of NO3-+NH4+, in a 2:1 ratio. Eleven-day old plants, two days after the initiation of lateral roots, were used for the experiments. Cell walls were isolated from lateral roots and primary root segments, 2-7 cm from tip to base, representing zones of intense or decreased growth rates, respectively. Protein content and the activity of enzymes peroxidase, malate dehydrogenase and ascorbate oxidase ionically or covalently bound to the walls, as well as cell wall phenolic content and antioxidant capacity, were determined. Cell walls of plants grown on mixed N possess more developed enzymatic antioxidant systems and lower non-enzymatic antioxidant defenses than cell walls grown on NO3-. Irrespective of N treatment, the activities of all studied enzymes and protein content were higher in cell walls of lateral compared to primary roots. Phenolic content of cell walls isolated from lateral roots was higher in NO3--grown than in mixed N grown plants. No significant differences could be observed in the isozyme patterns of cell wall peroxidases isolated from plants grown on different nutrient solution. Our results indicate that different N treatments modify the antioxidant systems of root cell walls. Treatment with NO3- resulted in an increase of constitutive phenolic content, while the combination of NO3-+NH4+ elevated the redox enzyme activities in root cell walls.

  6. Modification of antioxidant systems in cell walls of maize roots by different nitrogen sources

    Energy Technology Data Exchange (ETDEWEB)

    Hadži-Tašković Šukalović V; Vuletić, M.; Marković, K.; Željko, Vučinić; Kravić, N.

    2016-07-01

    Antioxidant systems of maize root cell walls grown on different nitrogen sources were evaluated. Plants were grown on a medium containing only NO3- or the mixture of NO3-+NH4+, in a 2:1 ratio. Eleven-day old plants, two days after the initiation of lateral roots, were used for the experiments. Cell walls were isolated from lateral roots and primary root segments, 2-7 cm from tip to base, representing zones of intense or decreased growth rates, respectively. Protein content and the activity of enzymes peroxidase, malate dehydrogenase and ascorbate oxidase ionically or covalently bound to the walls, as well as cell wall phenolic content and antioxidant capacity, were determined. Cell walls of plants grown on mixed N possess more developed enzymatic antioxidant systems and lower non-enzymatic antioxidant defenses than cell walls grown on NO3-. Irrespective of N treatment, the activities of all studied enzymes and protein content were higher in cell walls of lateral compared to primary roots. Phenolic content of cell walls isolated from lateral roots was higher in NO3--grown than in mixed N grown plants. No significant differences could be observed in the isozyme patterns of cell wall peroxidases isolated from plants grown on different nutrient solution. Our results indicate that different N treatments modify the antioxidant systems of root cell walls. Treatment with NO3- resulted in an increase of constitutive phenolic content, while the combination of NO3-+NH4+ elevated the redox enzyme activities in root cell walls.

  7. Expressed proteins of Herbaspirillum seropedicae in maize (DKB240) roots-bacteria interaction revealed using proteomics.

    Science.gov (United States)

    Ferrari, Cibele Santos; Amaral, Fernanda Plucani; Bueno, Jessica Cavalheiro Ferreira; Scariot, Mirella Christine; Valentim-Neto, Pedro Alexandre; Arisi, Ana Carolina Maisonnave

    2014-11-01

    Several molecular tools have been used to clarify the basis of plant-bacteria interaction; however, the mechanism behind the association is still unclear. In this study, we used a proteomic approach to investigate the root proteome of Zea mays (cv. DKB240) inoculated with Herbaspirillum seropedicae strain SmR1 grown in vitro and harvested 7 days after inoculation. Eighteen differentially accumulated proteins were observed in root samples, ten of which were identified by MALDI-TOF mass spectrometry peptide mass fingerprint. Among the identified proteins, we observed three proteins present exclusively in inoculated root samples and six upregulated proteins and one downregulated protein relative to control. Differentially expressed maize proteins were identified as hypothetical protein ZEAMMB73_483204, hypothetical protein ZEAMMB73_269466, and tubulin beta-7 chain. The following were identified as H. seropedicae proteins: peroxiredoxin protein, EF-Tu elongation factor protein, cation transport ATPase, NADPH:quinone oxidoreductase, dinitrogenase reductase, and type III secretion ATP synthase. Our results presented the first evidence of type III secretion ATP synthase expression during H. seropedicae-maize root interaction.

  8. 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.

  9. Changes in the transcriptomic profiles of maize roots in response to iron-deficiency stress.

    Science.gov (United States)

    Li, Yan; Wang, Nian; Zhao, Fengtao; Song, Xuejiao; Yin, Zhaohua; Huang, Rong; Zhang, Chunqing

    2014-07-01

    Plants are often subjected to iron (Fe)-deficiency stress because of its low solubility. Plants have evolved two distinct strategies to solubilize and transport Fe to acclimate to this abiotic stress condition. Transcriptomic profiling analysis was performed using Illumina digital gene expression to understand the mechanism underlying resistance responses of roots to Fe starvation in maize, an important Strategy II plant. A total of 3,427, 4,069, 4,881, and 2,610 genes had significantly changed expression levels after Fe-deficiency treatments of 1, 2, 4 or 7 days, respectively. Genes involved in 2'-deoxymugineic acid (DMA) synthesis, secretion, and Fe(III)-DMA uptake were significantly induced. Many genes related to plant hormones, protein kinases, and protein phosphatases responded to Fe-deficiency stress, suggesting their regulatory roles in response to the Fe-deficiency stress. Functional annotation clustering analysis, using the Database for Annotation, Visualization and Integrated Discovery, revealed maize root responses to Fe starvation. This resulted in 38 functional annotation clusters: 25 for up-regulated genes, and 13 for down-regulated ones. These included genes encoding enzymes involved in the metabolism of carboxylic acids, isoprenoids and aromatic compounds, transporters, and stress response proteins. Our work provides integrated information for understanding maize response to Fe-deficiency stress.

  10. Two major quantitative trait loci controlling the number of seminal roots in maize co-map with the root developmental genes rtcs and rum1.

    Science.gov (United States)

    Salvi, Silvio; Giuliani, Silvia; Ricciolini, Claudia; Carraro, Nicola; Maccaferri, Marco; Presterl, Thomas; Ouzunova, Milena; Tuberosa, Roberto

    2016-02-01

    The genetic dissection of root architecture and functions allows for a more effective and informed design of novel root ideotypes and paves the way to evaluate their effects on crop resilience to a number of abiotic stresses. In maize, limited attention has been devoted to the genetic analysis of root architecture diversity at the early stage. The difference in embryonic (including seminal and primary) root architecture between the maize reference line B73 (which mostly develops three seminal roots) and the landrace Gaspé Flint (with virtually no seminal roots) was genetically dissected using a collection of introgression lines grown in paper rolls and pots. Quantitative trait locus (QTL) analysis identified three QTLs controlling seminal root number (SRN) on chromosome bins 1.02, 3.07, and 8.04-8.05, which collectively explained 66% of the phenotypic variation. In all three cases, Gaspé Flint contributed the allele for lower SRN. Primary root dry weight was negatively correlated with SRN (r= -0.52), and QTLs for primary root size co-mapped with SRN QTLs, suggesting a pleiotropic effect of SRN QTLs on the primary root, most probably caused by competition for seed resources. Interestingly, two out of three SRN QTLs co-mapped with the only two known maize genes (rtcs and rum1) affecting the number of seminal roots. The strong additive effect of the three QTLs and the development of near isogenic lines for each QTL in the elite B73 background provide unique opportunities to characterize functionally the genes involved in root development and to evaluate how root architecture affects seedling establishment, early development, and eventually yield in maize. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  11. Associative bacteria influence maize (Zea mays L.) growth, physiology and root anatomy under different nitrogen levels.

    Science.gov (United States)

    Calzavara, Anderson Kikuchi; Paiva, Pedro Henrique Godoy; Gabriel, Lorrant Cavanha; de Oliveira, André Luiz Martinez; Milani, Karina; Oliveira, Halley Caixeta; Bianchini, Edmilson; Pimenta, José Antonio; de Oliveira, Maria Cristina Neves; Dias-Pereira, Jaqueline; Stolf-Moreira, Renata

    2018-05-15

    Despite the great diversity of plant growth-promoting bacteria (PGPB) with potential to partially replace the use of N-fertilizers in agriculture, few PGPB are explored for the production of commercial inoculants, reinforcing the importance of identifying positive plant-bacteria interactions. Aiming to better understand the influence of PGPB inoculation in plant development, two PGPB species with distant phylogenetic relationship were inoculated in maize. Maize seeds were inoculated with Bacillus sp. or Azospirillum brasilense. After germinating, the plants were subjected to two nitrogen treatments: full (N+) and limiting (N-) nitrogen supply. Then, anatomical, biometric and physiological analyses were performed. Both PGPB species modified the anatomical pattern of roots, as verified by the higher metaxylem vessel elements (MVE) number. Bacillus sp. also increased the MVE area in maize roots. Under N+ condition, both PGPB decreased the leaf protein content and led to the development of shorter roots; however, Bacillus sp. increased root and shoot dry weight, whereas A. brasilense increased photosynthesis rate and leaf nitrate content. In plants subjected to N limitation (N-), photosynthesis rate and photosystem II efficiency increased in those inoculated with Bacillus sp., whilst A. brasilense led to higher ammonium, amino acids and total soluble sugars contents in the leaves, compared to control. Plant developmental and metabolical patterns were switched by the inoculation, regardless the inoculant bacteria used, producing similar as well as distinct modifications on the parameters studied. These results indicatie that even non-diazotrophic inoculant strains can improve the plant N-status as result of the morpho-anatomical and physiological modifications produced by the PGPB. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  12. [Effects of sowing depth on seedling traits and root characteristics of summer maize].

    Science.gov (United States)

    Cao, Hui-ying; Wang, Ding-bo; Shi, Jian-guo; Zhu, Kun-lun; Dong, Shu-ting; Liu, Peng; Zhao, Bin; Zhang, Ji-wang

    2015-08-01

    Two summer maize hybrids, Zhengdan 958 (ZD958) and Xianyu 335 (XY335), were used as experimental materials. 4 sowing depths (3, 5, 7 and 9 cm) and uneven sowing depth (CK) were designed under sand culture and field experiments to investigate the effects of sowing depth on seedling traits and root characteristics of summer maize. The results showed that the seedling emergence rate gradually decreased and seedling emergence time gradually lengthened as the sowing depth increased. Compared with the sowing depth of 3 cm, the seedling emergence rates of ZD958 and XY335 sown at the depth of 9 cm were reduced by 9.4% and 11.8%, respectively, and the seedling emergence duration was prolonged 1.5 d. With the increasing sowing depth, the seedling length and uniformity decreased significantly, the mesocotyl length increased significantly, while the coleoptile length had no significant difference; the primary radicle length gradually decreased, the total length of secondary radicle gradually increased, and the total root length had no significant difference; the total dry mass of seedling and mesocotyl increased significantly, and the total root dry mass had no significant difference. With the increasing sowing depth, the soluble sugar content in each part of seedling increased and the amount of nutritional consumption of germinating seeds increased, the seedling root growth rate increased, but the root activity decreased, and the number of total nodal root and nodal layers increased. With the increasing sowing depth, harvested ears per unit area were reduced by decreased seedling emergence rate and seedling vigor, thus influenced the yield. In addition, uniform sowing depth could improve the canopy uniformity and relative characteristics, then increase the yield.

  13. Metabolic robustness in young roots underpins a predictive model of maize hybrid performance in the field.

    Science.gov (United States)

    de Abreu E Lima, Francisco; Westhues, Matthias; Cuadros-Inostroza, Álvaro; Willmitzer, Lothar; Melchinger, Albrecht E; Nikoloski, Zoran

    2017-04-01

    Heterosis has been extensively exploited for yield gain in maize (Zea mays L.). Here we conducted a comparative metabolomics-based analysis of young roots from in vitro germinating seedlings and from leaves of field-grown plants in a panel of inbred lines from the Dent and Flint heterotic patterns as well as selected F 1 hybrids. We found that metabolite levels in hybrids were more robust than in inbred lines. Using state-of-the-art modeling techniques, the most robust metabolites from roots and leaves explained up to 37 and 44% of the variance in the biomass from plants grown in two distinct field trials. In addition, a correlation-based analysis highlighted the trade-off between defense-related metabolites and hybrid performance. Therefore, our findings demonstrated the potential of metabolic profiles from young maize roots grown under tightly controlled conditions to predict hybrid performance in multiple field trials, thus bridging the greenhouse-field gap. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  14. Effect of subsoil tillage depth on nutrient accumulation, root distribution, and grain yield in spring maize

    Directory of Open Access Journals (Sweden)

    Hongguang Cai

    2014-10-01

    Full Text Available A four-year field experiment was conducted to investigate the effect of subsoiling depth on root morphology, nitrogen (N, phosphorus (P, and potassium (K uptake, and grain yield of spring maize. The results indicated that subsoil tillage promoted root development, increased nutrient accumulation, and increased yield. Compared with conventional soil management (CK, root length, root surface area, and root dry weight at 0–80 cm soil depth under subsoil tillage to 30 cm (T1 and subsoil tillage to 50 cm (T2 were significantly increased, especially the proportions of roots in deeper soil. Root length, surface area, and dry weight differed significantly among three treatments in the order of T2 > T1 > CK at the 12-leaf and early filling stages. The range of variation of root diameter in different soil layers in T2 treatment was the smallest, suggesting that roots were more likely to grow downwards with deeper subsoil tillage in soil. The accumulation of N, P, and K in subsoil tillage treatment was significantly increased, but the proportions of kernel and straw were different. In a comparison of T1 with T2, the grain accumulated more N and P, while K accumulation in kernel and straw varied in different years. Grain yield and biomass were increased by 12.8% and 14.6% on average in subsoil tillage treatments compared to conventional soil treatment. Although no significant differences between different subsoil tillage depths were observed for nutrient accumulation and grain yield, lodging resistance of plants was significantly improved in subsoil tillage to 50 cm, a characteristic that favors a high and stable yield under extreme environments.

  15. Root phosphatase activity, plant growth and phosphorus accumulation of maize genotypes

    Directory of Open Access Journals (Sweden)

    Machado Cynthia Torres de Toledo

    2004-01-01

    Full Text Available The activity of the enzyme phosphatase (P-ase is a physiological characteristic related to plant efficiency in relation to P acquisition and utilization, and is genetically variable. As part of a study on maize genotype characterization in relation to phosphorus (P uptake and utilization efficiency, two experiments were set up to measure phosphatase (P-ase activity in intact roots of six local and improved maize varieties and two sub-populations. Plants were grown at one P level in nutrient solution (4 mg L-1 and the P-ase activity assay was run using 17-day-old plants for varieties and 24-day-old plants for subpopulations. Shoot and root dry matter yields and P concentrations and contents in plant parts were determined, as well as P-efficiency indexes. Root P-ase activity differed among varieties, and highest enzimatic activities were observed in two local varieties -'Catetão' and 'Caiano' -and three improved varieties -'Sol da Manhã', 'Nitrodente' and 'BR 106'. 'Carioca', a local variety, had the lowest activity. Between subpopulations, 'ND2', with low yielding and poorly P-efficient plants, presented higher root P-ase activity as compared to 'ND10', high yielding and highly P-efficient plants. In general, subpopulations presented lower P-ase activities as compared to varieties. Positive and/or negative correlations were obtained between P-ase activity and P-efficiency characteristics, specific for the genotypes, not allowing inference on a general and clear association between root-secreted phosphatase and dry matter production or P acquisition. Genotypic variability must be known and considered before using P-ase activity as an indicator of P nutritional status, or P tolerance, adaptation and efficiency under low P conditions.

  16. Contribution of Root Traits to Phosphorus Acqusition Efficiency by Maize Landraces in Acid Soils of the Highlands in Central Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Bayuelo-Jimenez, J. S.; Hernandez-Bravo, N.; Magdaleno-Armas, M. L.; Perez-Decelis, V. A. [Instituto Nacional de Investigaciones Agropecuarias y Forestales, Universidad Michoacana de San Nicolas de Hidalgo, Tarimbaro, Michoacan (Mexico); Gallardo-Valdez, M. [Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias,. Campo Experimental Uruapan (Mexico); Ochoa, I. [Unipalma S.A. Bogota D.C. (Colombia); Paredes-Gutierrez, L. C. [Centro Nuclear Dr. Nabor Carrillo Flores, Instituto Nacional de Investigaciones Nucleares, Municipio de Ocoyoacac, Salazar (Mexico); Lynch, J. P. [Department of Horticulture, Pennsylvania State University, University Park, PA (United States)

    2013-11-15

    Plants have a wide range of mechanisms and morphological features that increase availability and acquisition of orthophosphate from soil. Root growth, root branching, and root hair morphology are important for the efficient acquisition of phosphorus (P). The series of studies reported here was based on the hypothesis that Mexican maize landraces, which have developed mostly in environments with low P availability and have a well-developed root system, could be a source of variation for the improvement of phosphorus acquisition. Several studies were conducted to evaluate genotypic variation in both root (root architecture and morphology, including root hairs) and plant growth traits associated with P acquisition efficiency (PAE) and/or P utilization efficiency (PUE) of maize landraces in a P-deficient Andisol in the Central Mexican Highlands, and to identify genotypic differences, among both efficient and inefficient in P acquisition and responsive and non-responsive maize landraces to applied P. The results showed that accessions differed greatly in plant growth, grain yield, root morphology, total uptake of P, PAE, PUE, and P efficiency defined as growth with suboptimal P availability. Phosphorus-efficient accessions had not only greater biomass per unit of absorbed P, but also larger root systems, greater P uptake per unit root weight, more nodal roots, nodal root laterals, and greater root hair density of nodal root main axes and first-order laterals than did Pinefficient accessions under P deficiency. Root biomass allocation, as quantified by the allometric partitioning coefficient (K) was not altered by P availability in the efficient accessions, but inefficient accessions had less biomass partitioning to roots (i.e. a lower K) under low P conditions. Accessions with enhanced nodal rooting and laterals had greater P uptake and growth under low P. Dense root hairs on nodal root main axes and first-order laterals conferred a marked benefit under low P, as

  17. 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.

  18. Transition zone cells reach G2 phase before initiating elongation in maize root apex

    Directory of Open Access Journals (Sweden)

    M. Victoria Alarcón

    2017-06-01

    Full Text Available Root elongation requires cell divisions in the meristematic zone and cell elongation in the elongation zone. The boundary between dividing and elongating cells is called the transition zone. In the meristem zone, initial cells are continuously dividing, but on the basal side of the meristem cells exit the meristem through the transition zone and enter in the elongation zone, where they stop division and rapidly elongate. Throughout this journey cells are accompanied by changes in cell cycle progression. Flow cytometry analysis showed that meristematic cells are in cycle, but exit when they enter the elongation zone. In addition, the percentage of cells in G2 phase (4C strongly increased from the meristem to the elongation zone. However, we did not observe remarkable changes in the percentage of cells in cell cycle phases along the entire elongation zone. These results suggest that meristematic cells in maize root apex stop the cell cycle in G2 phase after leaving the meristem.

  19. Use of genotype-environment interactions to elucidate the pattern of maize root plasticity to nitrogen deficiency.

    Science.gov (United States)

    Li, Pengcheng; Zhuang, Zhongjuan; Cai, Hongguang; Cheng, Shuai; Soomro, Ayaz Ali; Liu, Zhigang; Gu, Riliang; Mi, Guohua; Yuan, Lixing; Chen, Fanjun

    2016-03-01

    Maize (Zea mays L.) root morphology exhibits a high degree of phenotypic plasticity to nitrogen (N) deficiency, but the underlying genetic architecture remains to be investigated. Using an advanced BC4 F3 population, we investigated the root growth plasticity under two contrasted N levels and identified the quantitative trait loci (QTLs) with QTL-environment (Q × E) interaction effects. Principal components analysis (PCA) on changes of root traits to N deficiency (ΔLN-HN) showed that root length and biomass contributed for 45.8% in the same magnitude and direction on the first PC, while root traits scattered highly on PC2 and PC3. Hierarchical cluster analysis on traits for ΔLN-HN further assigned the BC4 F3 lines into six groups, in which the special phenotypic responses to N deficiency was presented. These results revealed the complicated root plasticity of maize in response to N deficiency that can be caused by genotype-environment (G × E) interactions. Furthermore, QTL mapping using a multi-environment analysis identified 35 QTLs for root traits. Nine of these QTLs exhibited significant Q × E interaction effects. Taken together, our findings contribute to understanding the phenotypic and genotypic pattern of root plasticity to N deficiency, which will be useful for developing maize tolerance cultivars to N deficiency. © 2015 Institute of Botany, Chinese Academy of Sciences.

  20. Developmental distribution of the plasma membrane-enriched proteome in the maize primary root growth zone

    Directory of Open Access Journals (Sweden)

    Zhe eZhang

    2013-03-01

    Full Text Available Within the growth zone of the maize primary root, there are well-defined patterns of spatial and temporal organization of cell division and elongation. However, the processes underlying this organization remain poorly understood. To gain additional insights into the differences amongst the defined regions, we performed a proteomic analysis focusing on fractions enriched for plasma membrane (PM proteins. The PM is the interface between the plant cell and the apoplast and/or extracellular space. As such, it is a key structure involved in the exchange of nutrients and other molecules as well as in the integration of signals that regulate growth and development. Despite the important functions of PM-localized proteins in mediating these processes, a full understanding of dynamic changes in PM proteomes is often impeded by low relative concentrations relative to total proteins. Using a relatively simple strategy of treating microsomal fractions with Brij-58 detergent to enrich for PM proteins, we compared the developmental distribution of proteins within the root growth zone which revealed a number of previously known as well as novel proteins with interesting patterns of abundance. For instance, the quantitative proteomic analysis detected a gradient of PM aquaporin proteins similar to that previously reported using immunoblot analyses, confirming the veracity of this strategy. Cellulose synthases increased in abundance with increasing distance from the root apex, consistent with expected locations of cell wall deposition. The similar distribution pattern for Brittle-stalk-2-like protein 3 implicate that this protein may also have cell wall related functions. These results show that the simplified PM enrichment method previously demonstrated in Arabidopsis can be successfully applied to completely unrelated plant tissues and provide insights into differences in the PM proteome throughout growth and development zones of the maize primary root.

  1. Developmental distribution of the plasma membrane-enriched proteome in the maize primary root growth zone.

    Science.gov (United States)

    Zhang, Zhe; Voothuluru, Priyamvada; Yamaguchi, Mineo; Sharp, Robert E; Peck, Scott C

    2013-01-01

    Within the growth zone of the maize primary root, there are well-defined patterns of spatial and temporal organization of cell division and elongation. However, the processes underlying this organization remain poorly understood. To gain additional insights into the differences amongst the defined regions, we performed a proteomic analysis focusing on fractions enriched for plasma membrane (PM) proteins. The PM is the interface between the plant cell and the apoplast and/or extracellular space. As such, it is a key structure involved in the exchange of nutrients and other molecules as well as in the integration of signals that regulate growth and development. Despite the important functions of PM-localized proteins in mediating these processes, a full understanding of dynamic changes in PM proteomes is often impeded by low relative concentrations relative to total proteins. Using a relatively simple strategy of treating microsomal fractions with Brij-58 detergent to enrich for PM proteins, we compared the developmental distribution of proteins within the root growth zone which revealed a number of previously known as well as novel proteins with interesting patterns of abundance. For instance, the quantitative proteomic analysis detected a gradient of PM aquaporin proteins similar to that previously reported using immunoblot analyses, confirming the veracity of this strategy. Cellulose synthases increased in abundance with increasing distance from the root apex, consistent with expected locations of cell wall deposition. The similar distribution pattern for Brittle-stalk-2-like protein implicates that this protein may also have cell wall related functions. These results show that the simplified PM enrichment method previously demonstrated in Arabidopsis can be successfully applied to completely unrelated plant tissues and provide insights into differences in the PM proteome throughout growth and development zones of the maize primary root.

  2. Iron Retention in Root Hemicelluloses Causes Genotypic Variability in the Tolerance to Iron Deficiency-Induced Chlorosis in Maize

    Directory of Open Access Journals (Sweden)

    Rongli Shi

    2018-04-01

    Full Text Available Antagonistic interactions of phosphorus (P hamper iron (Fe acquisition by plants and can cause Fe deficiency-induced chlorosis. To determine the physiological processes underlying adverse Fe–P interactions, the maize lines B73 and Mo17, which differ in chlorosis susceptibility, were grown hydroponically at different Fe:P ratios. In the presence of P, Mo17 became more chlorotic than B73. The higher sensitivity of Mo17 to Fe deficiency was not related to Fe–P interactions in leaves but to lower Fe translocation to shoots, which coincided with a larger pool of Fe being fixed in the root apoplast of P-supplied Mo17 plants. Fractionating cell wall components from roots showed that most of the cell wall-contained P accumulated in pectin, whereas most of the Fe was bound to root hemicelluloses, revealing that co-precipitation of Fe and P in the apoplast was not responsible for Fe inactivation in roots. A negative correlation between chlorophyll index and hemicellulose-bound Fe in 85 inbred lines of the intermated maize B73 × Mo17 (IBM population indicated that apoplastic Fe retention contributes to genotypic differences in chlorosis susceptibility of maize grown under low Fe supplies. Our study indicates that Fe retention in the hemicellulose fraction of roots is an important determinant in the tolerance to Fe deficiency-induced chlorosis of graminaceous plant species with low phytosiderophore release, like maize.

  3. Measurements of water uptake of maize roots: insights for traits that influence water transport from the soil

    Science.gov (United States)

    Ahmed, Mutez A.; Zarebanadkouki, Mohsen; Kroener, Eva; Carminati, Andrea

    2015-04-01

    Water availability is a primary constraint to the global crop production. 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 water uptake in maize roots. 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. Maize plants were grown in aluminum containers (40×38×1 cm) filled with sandy soil. The soil was partitioned into different compartments using 1-cm-thick layers of coarse sand. When the plants were two weeks-old we injected D2O into selected soil compartments. The experiments were performed during the day (transpiring plants) and night (non transpiring plants). The transport of D2O into roots was simulated using a convection-diffusion numerical model of D2O transport into roots. By fitting the observed D2O transport we quantified the diffusion coefficient 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. Both during day and night measurements, D2O entered more quickly into lateral roots than into primary and seminal roots. The quick transport of D2O into laterals was caused by the small radius of lateral roots. The diffusion coefficient of lateral roots (4.68×10-7cm2s-1)was similar to that of the distal segments of seminal roots (4.72×10-7cm2s-1) and higher than of the proximal segments (1.42×10-7cm2s-1). Water uptake of lateral roots (1.64×10-5cms-1)was much higher than that of the distal segments of seminal roots (1.18×10-12cms-1). Water uptake of the proximal seminal segments was negligible. We conclude that the function of lateral

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

    Science.gov (United States)

    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.

  5. Regulation by nitrate of protein synthesis and translation of RNA in maize roots

    International Nuclear Information System (INIS)

    McClure, P.R.; Bouthyette, P.Y.

    1986-01-01

    Roots of maize seedlings were exposed to 35 S-methionine in the presence or absence of nitrate. Using SDS-PAGE, nitrate-induced changes in labeled polypeptides were noted in the soluble (at 92, 63 and 21kD) and organellar(at 14kD) fractions, as well as in a membrane fraction of putative tonoplast origin (at 31kD). No nitrate-induced changes were noted in a plasmamembrane-enriched fraction or in a membrane fraction of mixed origin. Total RNA from nitrate-treated and control roots was translated in a rabbit reticulocyte system. Five translation products (94, 63, 41, 39 and 21kD) were identified as nitrate-inducible by comparative gel electrophoresis. Changes in protein synthesis and translation of mRNA were apparent within 2-3 h after introduction of nitrate. Within 4-6 h after removal of nitrate, the level of nitrate-inducible translation products diminished to that of control roots. In contrast, the 31kD tonoplast polypeptide was still labeled 26 h after removal of external nitrate and 35 S-methionine. The results will be discussed in relation to the nitrate induction of nitrate reductase, nitrite reductase, and the nitrate uptake system

  6. Proliferation of maize (Zea mays L.) roots in response to localized supply of nitrate

    Science.gov (United States)

    Granato, T. C.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

    1989-01-01

    Maize (Zea mays L.) plants with two primary nodal root axes were grown for 8 d in flowing nutrient culture with each axis independently supplied with NO3-. Dry matter accumulation by roots was similar whether 1.0 mol m-3 NO3- was supplied to one or both axes. When NO3- was supplied to only one axis, however, accumulation of dry matter within the root system was significantly greater in the axis supplied with NO3-. The increased dry matter accumulation by the +N-treated axis was attributable entirely to increased density and growth of lateral branches and not to a difference in growth of the primary axis. Proliferation of lateral branches for the +N axis was associated with the capacity for in situ reduction and utilization of a portion of the absorbed NO3-, especially in the apical region where lateral primordia are initiated. Although reduced nitrogen was translocated to the -N axis, concentrations in the -N axis remained significantly lower than in the +N axis. The concentration of reduced nitrogen, as well as in vitro NO3- reductase activity, was greater in apical than in more basal regions of the +N axis. The enhanced proliferation of lateral branches in the +N axis was accompanied by an increase in total respiration rate of the axis. Part of the increased respiration was attributable to increased mass of roots. The specific respiration rate (micromoles CO2 evolved per hour per gram root dry weight) was also greater for the +N than for the -N axis. If respiration rate is taken as representative of sink demand, stimulation of initiation and growth of laterals by in situ utilization of a localized exogenous supply of NO3- establishes an increased sink demand through enhanced metabolic activity and the increased partitioning of assimilates to the +N axis responds to the difference in sink demand between +N and -N axes.

  7. Root interactions in a maize/soybean intercropping system control soybean soil-borne disease, red crown rot.

    Directory of Open Access Journals (Sweden)

    Xiang Gao

    Full Text Available BACKGROUND: Within-field multiple crop species intercropping is well documented and used for disease control, but the underlying mechanisms are still unclear. As roots are the primary organ for perceiving signals in the soil from neighboring plants, root behavior may play an important role in soil-borne disease control. PRINCIPAL FINDINGS: In two years of field experiments, maize/soybean intercropping suppressed the occurrence of soybean red crown rot, a severe soil-borne disease caused by Cylindrocladium parasiticum (C. parasiticum. The suppressive effects decreased with increasing distance between intercropped plants under both low P and high P supply, suggesting that root interactions play a significant role independent of nutrient status. Further detailed quantitative studies revealed that the diversity and intensity of root interactions altered the expression of important soybean PR genes, as well as, the activity of corresponding enzymes in both P treatments. Furthermore, 5 phenolic acids were detected in root exudates of maize/soybean intercropped plants. Among these phenolic acids, cinnamic acid was released in significantly greater concentrations when intercropped maize with soybean compared to either crop grown in monoculture, and this spike in cinnamic acid was found dramatically constrain C. parasiticum growth in vitro. CONCLUSIONS: To the best of our knowledge, this study is the first report to demonstrate that intercropping with maize can promote resistance in soybean to red crown rot in a root-dependent manner. This supports the point that intercropping may be an efficient ecological strategy to control soil-borne plant disease and should be incorporated in sustainable agricultural management practices.

  8. Fine Mapping of qroot-yield-1.06, a QTL for Root, Plant Vigor and Yield in Maize

    OpenAIRE

    Martinez Ascanio, Ana Karine

    2015-01-01

    Root-yield-1.06 is a major QTL affecting root system architecture (RSA) and other agronomic traits in maize. The effect of this QTL has been evaluated with the development of near isogenic lines (NILs) differing at the QTL position. The objective of this study was to fine map qroot-yield-1.06 by marker-assisted searching for chromosome recombinants in the QTL interval and concurrent root phenotyping in both controlled and field conditions, through successive generations. Complementary approac...

  9. Investigation on the Assimilation of Nitrogen by Maize Roots and the Transport of Some Major Nitrogen Compounds by Xylem Sap. III

    DEFF Research Database (Denmark)

    Ivanko, S.; Ingversen, J.

    1971-01-01

    Xylem sap was collected from nitrogen-starved maize plants and investigations were made on the nitrogen transported. It appears from the results that several pools for different amino acids exist, which have different relations to the transport of nitrogen taken up. While in maize roots Glu, Glu...

  10. Sugar-starvation-induced changes of carbon metabolism in excised maize root tips

    International Nuclear Information System (INIS)

    Dieuaide-Noubhani, M.; Canioni, P.; Raymond, P.

    1997-01-01

    Excised maize (Zea mays L.) root tips were used to study the early metabolic effects of glucose (Glc) starvation. Root tips were prelabeled with [1-13C]Glc so that carbohydrates and metabolic intermediates were close to steady-state labeling, but lipids and proteins were scarcely labeled. They were then incubated in a sugar-deprived medium for carbon starvation. Changes in the level of soluble sugars, the respiratory quotient, and the 13C enrichment of intermediates, as measured by 13C and 1H nuclear magnetic resonance, were studied to detect changes in carbon fluxes through glycolysis and the tricarboxylic acid cycle. Labeling of glutamate carbons revealed two major changes in carbon input into the tricarboxylic acid cycle: (a) the phosphoenolpyruvate carboxylase flux stopped early after the start of Glc starvation, and (b) the contribution of glycolysis as the source of acetyl-coenzyme A for respiration decreased progressively, indicating an increasing contribution of the catabolism of protein amino acids, fatty acids, or both. The enrichment of glutamate carbons gave no evidence for proteolysis in the early steps of starvation, indicating that the catabolism of proteins was delayed compared with that of fatty acids. Labeling of carbohydrates showed that sucrose turnover continues during sugar starvation, but gave no indication for any significant flux through gluconeogenesis

  11. Anatomia radicular de milho em solo compactado Anatomy of maize roots in compacted soil

    Directory of Open Access Journals (Sweden)

    Anderson Cristian Bergamin

    2010-03-01

    Full Text Available O objetivo deste trabalho foi avaliar a relação entre a estrutura anatômica das raízes de milho e os atributos físicos de solo submetido a diferentes graus de compactação. O estudo foi realizado em campo, no Município de Dourados, MS, em Latossolo Vermelho distroférrico, textura muito argilosa. O delineamento experimental foi o de blocos ao acaso, com cinco repetições. O solo utilizado apresentava histórico de oito anos com plantio direto. A compactação adicional do solo foi realizada por meio de tráfego com trator, com uma (PDc1, duas (PDc2, quatro (PDc4 e seis passadas (PDc6 sucessivas, sobre toda a área da parcela. Houve aumento na razão entre o córtex e o cilindro vascular da raiz com o aumento na compactação do solo. Essa razão correlacionou-se negativamente com a macroporosidade e positivamente com a densidade do solo e com a resistência do solo à penetração. O grau de compactação afeta a anatomia radicular do milho, e a resistência do solo à penetração é o indicador físico que melhor expressa esse efeito.The objective of this work was to evaluate the relationship between maize root anatomy and physical attributes of soil subjected to levels of compaction. The experiment was carried out in field conditions, in Dourados, Mato Grosso do Sul state, Brazil, in a clayed Latossolo Vermelho (Rhodic Acrustox. A randomized complete block design was used, with five replicates. The soil was cultivated for eight years under no-tillage. The additional compaction of the soil was done by tractor traffic in one (PDc1, two (PDc2, four (PDc4 and six successive passes (PDc6, in the entire area of the experimental plots. Ratio between the cortex and vascular cylinder of the root increased with soil compaction. This ratio was negatively correlated to macroporosity, and positively to soil density and soil penetration resistance. Soil compaction level affects the anatomy of maize roots, and its penetration resistance is the best

  12. The Aux/IAA gene rum1 involved in seminal and lateral root formation controls vascular patterning in maize (Zea mays L.) primary roots.

    Science.gov (United States)

    Zhang, Yanxiang; Paschold, Anja; Marcon, Caroline; Liu, Sanzhen; Tai, Huanhuan; Nestler, Josefine; Yeh, Cheng-Ting; Opitz, Nina; Lanz, Christa; Schnable, Patrick S; Hochholdinger, Frank

    2014-09-01

    The maize (Zea mays L.) Aux/IAA protein RUM1 (ROOTLESS WITH UNDETECTABLE MERISTEMS 1) controls seminal and lateral root initiation. To identify RUM1-dependent gene expression patterns, RNA-Seq of the differentiation zone of primary roots of rum1 mutants and the wild type was performed in four biological replicates. In total, 2 801 high-confidence maize genes displayed differential gene expression with Fc ≥2 and FDR ≤1%. The auxin signalling-related genes rum1, like-auxin1 (lax1), lax2, (nam ataf cuc 1 nac1), the plethora genes plt1 (plethora 1), bbm1 (baby boom 1), and hscf1 (heat shock complementing factor 1) and the auxin response factors arf8 and arf37 were down-regulated in the mutant rum1. All of these genes except nac1 were auxin-inducible. The maize arf8 and arf37 genes are orthologues of Arabidopsis MP/ARF5 (MONOPTEROS/ARF5), which controls the differentiation of vascular cells. Histological analyses of mutant rum1 roots revealed defects in xylem organization and the differentiation of pith cells around the xylem. Moreover, histochemical staining of enlarged pith cells surrounding late metaxylem elements demonstrated that their thickened cell walls displayed excessive lignin deposition. In line with this phenotype, rum1-dependent mis-expression of several lignin biosynthesis genes was observed. In summary, RNA-Seq of RUM1-dependent gene expression in maize primary roots, in combination with histological and histochemical analyses, revealed the specific regulation of auxin signal transduction components by RUM1 and novel functions of RUM1 in vascular development. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  13. Complete disintegration of the microtubular cytoskeleton precedes its auxin-mediated reconstruction in postmitotic maize root cells

    Science.gov (United States)

    Baluska, F.; Barlow, P. W.; Volkmann, D.

    1996-01-01

    The inhibitory action of 0.1 microM auxin (IAA) on maize root growth was closely associated with a rapid and complete disintegration of the microtubular (MT) cytoskeleton, as visualized by indirect immunofluorescence of tubulin, throughout the growth region. After 30 min of this treatment, only fluorescent spots were present in root cells, accumulating either around nuclei or along cell walls. Six h later, in addition to some background fluorescence, dense but partially oriented oblique or longitudinal arrays of cortical MTs (CMTs) were found in most growing cells of the root apex. After 24 h of treatment, maize roots had adapted to the auxin, as inferred from the slowly recovering elongation rate and from the reassembly of a dense and well-ordered MT cytoskeleton which showed only slight deviations from that of the control root cells. Taxol pretreatment (100 microM, 24 h) prevented not only the rapid auxin-mediated disintegration of the MT cytoskeleton but also a reorientation of the CMT arrays, from transversal to longitudinal. The only tissue to show MTs in their cells throughout the auxin treatment was the epidermis. Significant resistance of transverse CMT arrays in these cells towards auxin was confirmed using a higher auxin concentration (100 microM, 24 h). The latter auxin dose also revealed inter-tissue-specific responses to auxin: outer cortical cell files reoriented their CMTs from the transversal to longitudinal orientation, whereas inner cortical cell files lost their MTs. This high auxin-mediated response, associated with the swelling of root apices, was abolished with the pretreatment of maize root with taxol.

  14. Morphological plasticity of root growth under mild water stress increases water use efficiency without reducing yield in maize

    Science.gov (United States)

    Cai, Qian; Zhang, Yulong; Sun, Zhanxiang; Zheng, Jiaming; Bai, Wei; Zhang, Yue; Liu, Yang; Feng, Liangshan; Feng, Chen; Zhang, Zhe; Yang, Ning; Evers, Jochem B.; Zhang, Lizhen

    2017-08-01

    A large yield gap exists in rain-fed maize (Zea mays L.) production in semi-arid regions, mainly caused by frequent droughts halfway through the crop-growing period due to uneven distribution of rainfall. It is questionable whether irrigation systems are economically required in such a region since the total amount of rainfall does generally meet crop requirements. This study aimed to quantitatively determine the effects of water stress from jointing to grain filling on root and shoot growth and the consequences for maize grain yield, above- and below-ground dry matter, water uptake (WU) and water use efficiency (WUE). Pot experiments were conducted in 2014 and 2015 with a mobile rain shelter to achieve conditions of no, mild or severe water stress. Maize yield was not affected by mild water stress over 2 years, while severe stress reduced yield by 56 %. Both water stress levels decreased root biomass slightly but shoot biomass substantially. Mild water stress decreased root length but increased root diameter, resulting in no effect on root surface area. Due to the morphological plasticity in root growth and the increase in root / shoot ratio, WU under water stress was decreased, and overall WUE for both above-ground dry matter and grain yield increased. Our results demonstrate that an irrigation system might be not economically and ecologically necessary because the frequently occurring mild water stress did not reduce crop yield much. The study helps us to understand crop responses to water stress during a critical water-sensitive period (middle of the crop-growing season) and to mitigate drought risk in dry-land agriculture.

  15. Root-Expressed Maize Lipoxygenase 3 Negatively Regulates Induced Systemic Resistance to Colletotrichum graminicola in Shoots

    Directory of Open Access Journals (Sweden)

    Nasie eConstantino

    2013-12-01

    Full Text Available We have previously reported that disruption of a maize root-expressed 9-lipoxygenase (9-LOX gene, ZmLOX3, results in dramatic increase in resistance to diverse leaf and stalk pathogens. Despite evident economic significance of these findings, the mechanism behind this increased resistance remained elusive. In this study, we show that increased resistance of the lox3-4 mutants is due to constitutive activation of induced systemic resistance (ISR signaling. We showed that ZmLOX3 lacked expression in leaves in response to anthracnose leaf blight pathogen Colletotrichum graminicola, but was expressed constitutively in the roots, thus prompting our hypothesis: the roots of lox3-4 mutants are the source of increased resistance in leaves. Supporting this hypothesis, treatment of wild-type plants (WT with xylem sap of lox3-4 mutant induced resistance to C. graminicola to the levels comparable to those observed in lox3-4 mutant. Moreover, treating mutants with the sap collected from WT plants partially restored the susceptibility to C. graminicola. lox3-4 mutants showed primed defense responses upon infection, which included earlier and greater induction of defense-related PAL and GST genes compared to WT. In addition to the greater expression of the octadecanoid pathway genes, lox3-4 mutant responded earlier and with a greater accumulation of H2O2 in response to C. graminicola infection or treatment with alamethicin. These findings suggest that lox3-4 mutants display constitutive ISR-like signaling. In support of this idea, root colonization by Trichoderma virens strain GV29-8 induced the same level of disease resistance in WT as the treatment with the mutant sap, but had no additional resistance effect in lox3-4 mutant. While treatment with T. virens GV29 strongly and rapidly suppressed ZmLOX3 expression in hydroponically grown WT roots, T. virens Δsml mutant, which is deficient in ISR induction, was unable to suppress expression of ZmLOX3, thus

  16. PURIFICATION OF Cd-BINDING PROTEIN FROM MAIZE ROOTS BY REVERSE-PHASE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

    Institute of Scientific and Technical Information of China (English)

    何笃修; 罗建沅; 全胜

    1991-01-01

    An efficient procedure of purification of Cd-binding protein in roots of maize has been established. Young seedlings of maize were exposed to a medium containing CdCl2 to induce the production of Cd-binding protein in their roots. The protein was purified after heat treatment by ion-exchange chromatography and reverse-phase HPLC. The resulting protein was identified as a purified product by N-terminal amino acid with the dansyl method. Its molecular weight was 3200 dalton, the cysteine content was 29.5%, about 3 Cd atoms were bound to one molecule of the protein and the Cd : cystine ratio was 1 : 2.3. According to its character, this protein could be a kind of plant metallothionein-like protein.

  17. Differential expression of α-L-arabinofuranosidases during maize (Zea mays L.) root elongation.

    Science.gov (United States)

    Kozlova, Liudmila V; Gorshkov, Oleg V; Mokshina, Natalia E; Gorshkova, Tatyana A

    2015-05-01

    Specific α- l -arabinofuranosidases are involved in the realisation of elongation growth process in cells with type II cell walls. Elongation growth in a plant cell is largely based on modification of the cell wall. In type II cell walls, the Ara/Xyl ratio is known to decrease during elongation due to the partial removal of Ara residues from glucuronoarabinoxylan. We searched within the maize genome for the genes of all predicted α-L-arabinofuranosidases that may be responsible for such a process and related their expression to the activity of the enzyme and the amount of free arabinose measured in six zones of a growing maize root. Eight genes of the GH51 family (ZmaABFs) and one gene of the GH3 family (ZmaARA-I) were identified. The abundance of ZmaABF1 and 3-6 transcripts was highly correlated with the measured enzymatic activity and free arabinose content that significantly increased during elongation. The transcript abundances also coincided with the pattern of changes in the Ara/Xyl ratio of the xylanase-extractable glucuronoarabinoxylan described in previous studies. The expression of ZmaABF3, 5 and 6 was especially up-regulated during elongation although corresponding proteins are devoid of the catalytic glutamate at the proper position. ZmaABF2 transcripts were specifically enriched in the root cap and meristem. A single ZmaARA-I gene was not expressed as a whole gene but instead as splice variants that encode the C-terminal end of the protein. Changes in the ZmaARA-I transcript level were rather moderate and had no significant correlation with free arabinose content. Thus, elongation growth of cells with type II cell walls is accompanied by the up-regulation of specific and predicted α-L-arabinofuranosidase genes, and the corresponding activity is indeed pronounced and is important for the modification of glucuronoarabinoxylan, which plays a key role in the modification of the cell wall supramolecular organisation.

  18. Maize water status and physiological traits as affected by root endophytic fungus Piriformospora indica under combined drought and mechanical stresses.

    Science.gov (United States)

    Hosseini, Fatemeh; Mosaddeghi, Mohammad Reza; Dexter, Anthony Roger; Sepehri, Mozhgan

    2018-05-01

    Under combined drought and mechanical stresses, mechanical stress primarily controlled physiological responses of maize. Piriformospora indica mitigated the adverse effects of stresses, and inoculated maize experienced less oxidative damage and had better adaptation to stressful conditions. The objective of this study was to investigate the effect of maize root colonization by an endophytic fungus P. indica on plant water status, physiological traits and root morphology under combined drought and mechanical stresses. Seedlings of inoculated and non-inoculated maize (Zea mays L., cv. single cross 704) were cultivated in growth chambers filled with moistened siliceous sand at a matric suction of 20 hPa. Drought stress was induced using PEG 6000 solution with osmotic potentials of 0, - 0.3 and - 0.5 MPa. Mechanical stress (i.e., penetration resistances of 1.05, 4.23 and 6.34 MPa) was exerted by placing weights on the surface of the sand medium. After 30 days, leaf water potential (LWP) and relative water content (RWC), root and shoot fresh weights, root volume (RV) and diameter (RD), leaf proline content, leaf area (LA) and catalase (CAT) and ascorbate peroxidase (APX) activities were measured. The results show that exposure to individual drought and mechanical stresses led to higher RD and proline content and lower plant biomass, RV and LA. Moreover, increasing drought and mechanical stress severity increased APX activity by about 1.9- and 3.1-fold compared with the control. When plants were exposed to combined stresses, mechanical stress played the dominant role in controlling plant responses. P. indica-inoculated plants are better adapted to individual and combined stresses. The inoculated plants had greater RV, LA, RWC, LWP and proline content under stressful conditions. In comparison with non-inoculated plants, inoculated plants showed lower CAT and APX activities which means that they experienced less oxidative stress induced by stressful conditions.

  19. Morphological plasticity of root growth under mild water stress increases water use efficiency without reducing yield in maize

    Directory of Open Access Journals (Sweden)

    Q. Cai

    2017-08-01

    Full Text Available A large yield gap exists in rain-fed maize (Zea mays L. production in semi-arid regions, mainly caused by frequent droughts halfway through the crop-growing period due to uneven distribution of rainfall. It is questionable whether irrigation systems are economically required in such a region since the total amount of rainfall does generally meet crop requirements. This study aimed to quantitatively determine the effects of water stress from jointing to grain filling on root and shoot growth and the consequences for maize grain yield, above- and below-ground dry matter, water uptake (WU and water use efficiency (WUE. Pot experiments were conducted in 2014 and 2015 with a mobile rain shelter to achieve conditions of no, mild or severe water stress. Maize yield was not affected by mild water stress over 2 years, while severe stress reduced yield by 56 %. Both water stress levels decreased root biomass slightly but shoot biomass substantially. Mild water stress decreased root length but increased root diameter, resulting in no effect on root surface area. Due to the morphological plasticity in root growth and the increase in root ∕ shoot ratio, WU under water stress was decreased, and overall WUE for both above-ground dry matter and grain yield increased. Our results demonstrate that an irrigation system might be not economically and ecologically necessary because the frequently occurring mild water stress did not reduce crop yield much. The study helps us to understand crop responses to water stress during a critical water-sensitive period (middle of the crop-growing season and to mitigate drought risk in dry-land agriculture.

  20. QTL-By-Environment Interaction in the Response of Maize Root and Shoot Traits to Different Water Regimes

    Directory of Open Access Journals (Sweden)

    Pengcheng Li

    2018-02-01

    Full Text Available Drought is a major abiotic stress factor limiting maize production, and elucidating the genetic control of root system architecture and plasticity to water-deficit stress is a crucial problem to improve drought adaptability. In this study, 13 root and shoot traits and genetic plasticity were evaluated in a recombinant inbred line (RIL population under well-watered (WW and water stress (WS conditions. Significant phenotypic variation was observed for all observed traits both under WW and WS conditions. Most of the measured traits showed significant genotype–environment interaction (GEI in both environments. Strong correlations were observed among traits in the same class. Multi-environment (ME and multi-trait (MT QTL analyses were conducted for all observed traits. A total of 48 QTLs were identified by ME, including 15 QTLs associated with 9 traits showing significant QTL-by-Environment interactions (QEI. QTLs associated with crown root angle (CRA2 and crown root length (CRL1 were identified as having antagonistic pleiotropic effects, while 13 other QTLs showed signs of conditional neutrality (CN, including 9 and 4 QTLs detected under WW and WS conditions, respectively. MT analysis identified 14 pleiotropic QTLs for 13 traits, SNP20 (1@79.2 cM was associated with the length of crown root (CR, primary root (PR, and seminal root (SR and might contribute to increases in root length under WS condition. Taken together, these findings contribute to our understanding of the phenotypic and genotypic patterns of root plasticity in response to water deficiency, which will be useful to improve drought tolerance in maize.

  1. Mineral nitrogen sources differently affect root glutamine synthetase isoforms and amino acid balance among organs in maize.

    Science.gov (United States)

    Prinsi, Bhakti; Espen, Luca

    2015-04-03

    Glutamine synthetase (GS) catalyzes the first step of nitrogen assimilation in plant cell. The main GS are classified as cytosolic GS1 and plastidial GS2, of which the functionality is variable according to the nitrogen sources, organs and developmental stages. In maize (Zea mays L.) one gene for GS2 and five genes for GS1 subunits are known, but their roles in root metabolism are not yet well defined. In this work, proteomic and biochemical approaches have been used to study root GS enzymes and nitrogen assimilation in maize plants re-supplied with nitrate, ammonium or both. The plant metabolic status highlighted the relevance of root system in maize nitrogen assimilation during both nitrate and ammonium nutrition. The analysis of root proteomes allowed a study to be made of the accumulation and phosphorylation of six GS proteins. Three forms of GS2 were identified, among which only the phosphorylated one showed an accumulation trend consistent with plastidial GS activity. Nitrogen availabilities enabled increments in root total GS synthetase activity, associated with different GS1 isoforms according to the nitrogen sources. Nitrate nutrition induced the specific accumulation of GS1-5 while ammonium led to up-accumulation of both GS1-1 and GS1-5, highlighting co-participation. Moreover, the changes in thermal sensitivity of root GS transferase activity suggested differential rearrangements of the native enzyme. The amino acid accumulation and composition in roots, xylem sap and leaves deeply changed in response to mineral sources. Glutamine showed the prevalent changes in all nitrogen nutritions. Besides, the ammonium nutrition was associated with an accumulation of asparagine and reducing sugars and a drop in glutamic acid level, significantly alleviated by the co-provision with nitrate. This work provides new information about the multifaceted regulation of the GS enzyme in maize roots, indicating the involvement of specific isoenzymes/isoforms, post

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

    Science.gov (United States)

    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.

  3. 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

  4. The plasma membrane proteome of maize roots grown under low and high iron conditions.

    Science.gov (United States)

    Hopff, David; Wienkoop, Stefanie; Lüthje, Sabine

    2013-10-08

    Iron (Fe) homeostasis is essential for life and has been intensively investigated for dicots, while our knowledge for species in the Poaceae is fragmentary. This study presents the first proteome analysis (LC-MS/MS) of plasma membranes isolated from roots of 18-day old maize (Zea mays L.). Plants were grown under low and high Fe conditions in hydroponic culture. In total, 227 proteins were identified in control plants, whereas 204 proteins were identified in Fe deficient plants and 251 proteins in plants grown under high Fe conditions. Proteins were sorted by functional classes, and most of the identified proteins were classified as signaling proteins. A significant number of PM-bound redox proteins could be identified including quinone reductases, heme and copper-containing proteins. Most of these components were constitutive, and others could hint at an involvement of redox signaling and redox homeostasis by change in abundance. Energy metabolism and translation seem to be crucial in Fe homeostasis. The response to Fe deficiency includes proteins involved in development, whereas membrane remodeling and assembly and/or repair of Fe-S clusters is discussed for Fe toxicity. The general stress response appears to involve proteins related to oxidative stress, growth regulation, an increased rigidity and synthesis of cell walls and adaption of nutrient uptake and/or translocation. This article is part of a Special Issue entitled: Plant Proteomics in Europe. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. High-resolution quantification of root dynamics in split-nutrient rhizoslides reveals rapid and strong proliferation of maize roots in response to local high nitrogen.

    Science.gov (United States)

    in 't Zandt, Dina; Le Marié, Chantal; Kirchgessner, Norbert; Visser, Eric J W; Hund, Andreas

    2015-09-01

    The plant's root system is highly plastic, and can respond to environmental stimuli such as high nitrogen (N) in patches. A root may respond to an N patch by selective placement of new lateral roots, and therewith increases root N uptake. This may be a desirable trait in breeding programmes, since it decreases NO3(-) leaching and N2O emission. Roots of maize (Zea mays L.) were grown without N in split-nutrient rhizoslides. One side of the slides was exposed to high N after 15 d of root development, and root elongation was measured for another 15 d, described in a time course model and parameterized. The elongation rates of crown axile roots on the N-treated side of the plant followed a logistic increase to a maximum of 5.3cm d(-1); 95% of the maximum were reached within 4 d. At the same time, on the untreated side, axile root elongation dropped linearly to 1.2cm d(-1) within 6.4 d and stayed constant thereafter. Twice as many lateral roots were formed on the crown axis on the N side compared to the untreated side. Most strikingly, the elongation rates of laterals of the N side increased linearly with most of the roots reaching an asymptote ~8 d after start of the N treatment. By contrast, laterals on the side without N did not show any detectable elongation beyond the first day after their emergence. We conclude that split-nutrient rhizoslides have great potential to improve our knowledge about nitrogen responsiveness and selection for contrasting genotypes. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  6. Investigation on the Assimilation of Nitrogen by Maize Roots and the Transport of Some Major Nitrogen Compounds by Xylem Sap. II

    DEFF Research Database (Denmark)

    Ingversen, J.; Ivanko, S.

    1971-01-01

    The amino acid and protein metabolism of roots of maize has been studied. The important role of the free amino acids and proteins of the roots as active agents in nitrogen assimilation is pointed out. Nitrogen supplied as nitrate is preferably incorporated into α-ketoglutaric acid, and then by tr...

  7. Neonate larvae of the specialist herbivore Diabrotica virgifera virgifera do not exploit the defensive volatile (E)-ß-caryophyllene in locating maize roots

    Science.gov (United States)

    The behavior of the neonate larvae of Diabrotica virgifera virgifera LeConte (western corn rootworm, WCR) was assessed in presence of maize root constitutively emitting (E)-ß-caryophylene (EßC). This root volatile has been shown to attract both second instar WCR and insect-killing nematodes, offerin...

  8. Nitrogen-15 uptake by whole plants and root callus cultures of inbred maize lines and their F1 hybrids

    International Nuclear Information System (INIS)

    Mladenova, Y.; Karadimova, M.

    1981-01-01

    The uptake of nitrogen-15 by 3 maize genotypes was investigated. Comparative analysis of N15 assimilation and distribution in the organs of intact plants of two self-pollinated lines and their F1 hybrid and also in a callus tissue of roots of the same genotypes was made. From the results the conclusion is drawn that the N-use efficiency of the female line is higher than that of the male line both in intact plants and callus tissues from roots. This fact indicates that the N-use efficiency is determined not only by the functions of the cells in the shoots, suggesting the participation of the photosynthetic carboxylases but also by the functions of cells without a photosynthesizing apparatus. The N-use efficiency in the F1 hybrid manifests ''heterosis'', in spite of the intact plants or root callus tissues are being studied. (author)

  9. The initiation of lateral roots in the primary roots of maize (Zea mays L.) implies a reactivation of cell proliferation in a group of founder pericycle cells.

    Science.gov (United States)

    Alarcón, M Victoria; Lloret, Pedro G; Martín-Partido, Gervasio; Salguero, Julio

    2016-03-15

    The initiation of lateral roots (LRs) has generally been viewed as a reactivation of proliferative activity in pericycle cells that are committed to initiate primordia. However, it is also possible that pericycle founder cells that initiate LRs never cease proliferative activity but rather are displaced to the most distal root zones while undertaking successive stages of LR initiation. In this study, we tested these two alternative hypotheses by examining the incorporation of 5-bromo-2'-deoxyuridine (BrdU) into the DNA of meristematic root cells of Zea mays. According to the values for the length of the cell cycle and values for cell displacement along the maize root, our results strongly suggest that pericycle cells that initiate LR primordia ceased proliferative activity upon exiting the meristematic zone. This finding is supported by the existence of a root zone between 4 and 20mm from the root cap junction, in which neither mitotic cells nor labelled nuclei were observed in phloem pericycle cells. Copyright © 2016 Elsevier GmbH. All rights reserved.

  10. Investigation on the Assimilation of Nitrogen by Maize Roots and the Transport of Some Major Nitrogen Compounds by Xylem Sap

    DEFF Research Database (Denmark)

    Ivanko, S.; Ingversen, J.

    1971-01-01

    The uptake and assimilation of nitrate and ammonia have been studied in Zea mays. Nitrogen-starved maize roots are capable of accumulating a potential capacity for nitrogen uptake and assimilation. Reestablishment of nitrogen supply leads to intense uptake, reaching 154 % of the reference variant...... level after 24 hours when nitrate is supplied, and 121 % when ammonia is supplied. After 24 hours the insoluble nitrogen fraction accounts for 80, 54 and 55 % of the total taken up in the PK + NO3-, PK + NH4+ and NPK variants respectively....

  11. Intensive field phenotyping of maize (Zea mays L.) root crowns identifies phenes and phene integration associated with plant growth and nitrogen acquisition.

    Science.gov (United States)

    York, Larry M; Lynch, Jonathan P

    2015-09-01

    Root architecture is an important regulator of nitrogen (N) acquisition. Existing methods to phenotype the root architecture of cereal crops are generally limited to seedlings or to the outer roots of mature root crowns. The functional integration of root phenes is poorly understood. In this study, intensive phenotyping of mature root crowns of maize was conducted to discover phenes and phene modules related to N acquisition. Twelve maize genotypes were grown under replete and deficient N regimes in the field in South Africa and eight in the USA. An image was captured for every whorl of nodal roots in each crown. Custom software was used to measure root phenes including nodal occupancy, angle, diameter, distance to branching, lateral branching, and lateral length. Variation existed for all root phenes within maize root crowns. Size-related phenes such as diameter and number were substantially influenced by nodal position, while angle, lateral density, and distance to branching were not. Greater distance to branching, the length from the shoot to the emergence of laterals, is proposed to be a novel phene state that minimizes placing roots in already explored soil. Root phenes from both older and younger whorls of nodal roots contributed to variation in shoot mass and N uptake. The additive integration of root phenes accounted for 70% of the variation observed in shoot mass in low N soil. These results demonstrate the utility of intensive phenotyping of mature root systems, as well as the importance of phene integration in soil resource acquisition. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  12. The effect of modifying rooting depths and nitrification inhibitors on nutrient uptake from organic biogas residues in maize

    Science.gov (United States)

    Dietrich, Charlotte C.; Koller, Robert; Nagel, Kerstin A.; Schickling, Anke; Schrey, Silvia D.; Jablonowski, Nicolai D.

    2017-04-01

    Optimizing the application of and nutrient uptake from organic nutrient sources, such as the nutrient-rich residues ("digestates") from the biogas industry, is becoming a viable option in remediating fertility on previously unsuitable soils for agricultural utilization. Proposedly, concurrent changes in root system architecture and functioning could also serve as the basis of future phytomining approaches. Herein, we evaluate the effect of spatial nutrient availability and nitrification on maize root architecture and nutrient uptake. We test these effects by applying maize-based digestate at a rate of 170 kg/ha in layers of varying depths (10, 25 and 40 cm) and through either the presence or absence of nitrification inhibitors. In order to regularly monitor above- and below-ground plant biomass production, we used the noninvasive phenotyping platform, GROWSCREEN-Rhizo at the Forschungszentrum Jülich, using rhizotrons (Nagel et al., 2012). Measured parameters included projected plant height and leaf area, as well as root length and spatial distribution. Additionally, root diameters were quantified after the destructive harvest, 21 days after sowing (DAS). Spatial nutrient availability significantly affected root system architecture, as for example root system size -the area occupied by roots- increased alongside nutrient layer depths. Fertilization also positively affected root length density (RLD). Within fertilized layers, the presence of nitrification inhibitors increased RLD by up to 30% and was most pronounced in the fine root biomass fraction (0.1 to 0.5mm). Generally, nitrification inhibitors promoted early plant growth by up to 45% across treatments. However, their effect varied in dependence of layer depths, leading to a time-delayed response in deeper layers, accounting for plants having to grow significantly longer roots in order to reach fertilized substrate. Nitrification inhibitors also initiated the comparatively early on-set of growth differences in

  13. A Low-Cost Imaging Method for the Temporal and Spatial Colorimetric Detection of Free Amines on Maize Root Surfaces

    Directory of Open Access Journals (Sweden)

    Truc H. Doan

    2017-08-01

    Full Text Available Plant root exudates are important mediators in the interactions that occur between plants and microorganisms in the soil, yet much remains to be learned about spatial and temporal variation in their production. This work outlines a method utilizing a novel colorimetric paper to detect spatial and temporal changes in the production of nitrogen-containing compounds on the root surface. While existing methods have made it possible to conduct detailed analysis of root exudate composition, relatively less is known about where in the root system exudates are produced and how this localization changes as the root grows. Furthermore, there is much to learn about how exudate localization and composition varies in response to stress. Root exudates are chemically diverse secretions composed of organic acids, amino acids, proteins, sugars, and other metabolites. The sensor utilized for the method, ninhydrin, is a colorless substance in solution that reacts with free amino groups to form a purple dye. A detection paper was developed by formulating ninhydrin into a print solution that was uniformly deposited onto paper with a commercial ink jet printer. This “ninhydrin paper” was used to analyze the chemical makeup of root surfaces from maize seedlings grown vertically on germination paper. Through contact between the ninhydrin paper and seedling root surfaces, combined with images of both the seedlings and dried ninhydrin papers captured using a standard flatbed scanner, nitrogen-containing substances on the root surface can be localized and concentration of signal estimated for over 2 weeks of development. The method was found to be non-inhibiting to plant growth over the analysis period although damage to root hairs was observed. The method is sensitive in the detection of free amines at concentrations as little as 140 μM. Furthermore, ninhydrin paper is stable, showing consistent color changes up to 2 weeks after printing. This relatively simple, low

  14. Regulation of H+ Extrusion and Cytoplasmic pH in Maize Root Tips Acclimated to a Low-Oxygen Environment.

    Science.gov (United States)

    Xia, J. H.; Roberts, JKM.

    1996-05-01

    We tested the hypothesis that H+ extrusion contributes to cytoplasmic pH regulation and tolerance of anoxia in maize (Zea mays) root tips. We studied root tips of whole seedlings that were acclimated to a low-oxygen environment by pretreatment in 3% (v/v) O2. Acclimated root tips characteristically regulate cytoplasmic pH near neutrality and survive prolonged anoxia, whereas nonacclimated tips undergo severe cytoplasmic acidosis and die much more quickly. We show that the plasma membrane H+-ATPase can operate under anoxia and that net H+ extrusion increases when cytoplasmic pH falls. However, at an external pH near 6.0, H+ extrusion contributes little to cytoplasmic pH regulation. At more acidic external pH values, net H+ flux into root tips increases dramatically, leading to a decrease in cytoplasmic pH and reduced tolerance of anoxia. We present evidence that, under these conditions, H+ pumps are activated to partly offset acidosis due to H+ influx and, thereby, contribute to cytoplasmic pH regulation and tolerance of anoxia. The regulation of H+ extrusion under anoxia is discussed with respect to the acclimation response and mechanisms of intracellular pH regulation in aerobic plant cells.

  15. The effect of altered dosage of a mutant allele of Teosinte branched 1 (tb1-ref) on the root system of modern maize.

    Science.gov (United States)

    Gaudin, Amelie C M; McClymont, Sarah A; Soliman, Sameh S M; Raizada, Manish N

    2014-02-14

    There was ancient human selection on the wild progenitor of modern maize, Balsas teosinte, for decreased shoot branching (tillering), in order to allow more nutrients to be diverted to grain. Mechanistically, the decline in shoot tillering has been associated with selection for increased expression of the major domestication gene Teosinte Branched 1 (Tb1) in shoot primordia. Therefore, TB1 has been defined as a repressor of shoot branching. It is known that plants respond to changes in shoot size by compensatory changes in root growth and architecture. However, it has not been reported whether altered TB1 expression affects any plant traits below ground. Previously, changes in dosage of a well-studied mutant allele of Tb1 in modern maize, called tb1-ref, from one to two copies, was shown to increase tillering. As a result, plants with two copies of the tb1-ref allele have a larger shoot biomass than heterozygotes. Here we used aeroponics to phenotype the effects of tb1-ref copy number on maize roots at macro-, meso- and micro scales of development. An increase in the tb1-ref copy number from one to two copies resulted in: (1) an increase in crown root number due to the cumulative initiation of crown roots from successive tillers; (2) higher density of first and second order lateral roots; and (3) reduced average lateral root length. The resulting increase in root system biomass in homozygous tb1-ref mutants balanced the increase in shoot biomass caused by enhanced tillering. These changes caused homozygous tb1-ref mutants of modern maize to more closely resemble its ancestor Balsas teosinte below ground. We conclude that a decrease in TB1 function in maize results in a larger root system, due to an increase in the number of crown roots and lateral roots. Given that decreased TB1 expression results in a more highly branched and larger shoot, the impact of TB1 below ground may be direct or indirect. We discuss the potential implications of these findings for whole

  16. The Apoplastic Secretome of Trichoderma virens During Interaction With Maize Roots Shows an Inhibition of Plant Defence and Scavenging Oxidative Stress Secreted Proteins

    Directory of Open Access Journals (Sweden)

    Guillermo Nogueira-Lopez

    2018-04-01

    Full Text Available In Nature, almost every plant is colonized by fungi. Trichoderma virens is a biocontrol fungus which has the capacity to behave as an opportunistic plant endophyte. Even though many plants are colonized by this symbiont, the exact mechanisms by which Trichoderma masks its entrance into its plant host remain unknown, but likely involve the secretion of different families of proteins into the apoplast that may play crucial roles in the suppression of plant immune responses. In this study, we investigated T. virens colonization of maize roots under hydroponic conditions, evidencing inter- and intracellular colonization by the fungus and modifications in root morphology and coloration. Moreover, we show that upon host penetration, T. virens secretes into the apoplast an arsenal of proteins to facilitate inter- and intracellular colonization of maize root tissues. Using a gel-free shotgun proteomics approach, 95 and 43 secretory proteins were identified from maize and T. virens, respectively. A reduction in the maize secretome (36% was induced by T. virens, including two major groups, glycosyl hydrolases and peroxidases. Furthermore, T. virens secreted proteins were mainly involved in cell wall hydrolysis, scavenging of reactive oxygen species and secondary metabolism, as well as putative effector-like proteins. Levels of peroxidase activity were reduced in the inoculated roots, suggesting a strategy used by T. virens to manipulate host immune responses. The results provide an insight into the crosstalk in the apoplast which is essential to maintain the T. virens-plant interaction.

  17. Effect of Piriformospora indica inoculation on root development and distribution of maize (Zea mays L.) in the presence of petroleum contaminated soil

    Science.gov (United States)

    Zamani, Javad; Hajabbasi, Mohammad Ali; Alaie, Ebrahim

    2014-05-01

    The root systems of most terrestrial plants are confronted to various abiotic and biotic stresses. One of these abiotic stresses is contamination of soil with petroleum hydrocarbon, which the efficiency of phytoremediation of petroleum hydrocarbons in soils is dependent on the ability of plant roots to development into the contaminated soils. Piriformospora indica represents a recently discovered fungus that transfers considerable beneficial impact to its host plants. A rhizotron experiment was conducted to study the effects of P. Indica inoculation on root distribution and root and shoot development of maize (Zea mays L.) in the presence of three patterns of petroleum contamination in the soil (subsurface contamination, continuous contamination and without contamination (control)). Root distribution and root and shoot development were monitored over time. The final root and shoot biomass and the final TPH concentration in the rhizosphere were determined. Analysis of digitized images which were prepared of the tracing of the appeared roots along the front rhizotrons showed the depth and total length of root network in the contamination treatments were significantly decreased. Although the degradation of TPH in the rhizosphere of maize was significant, but there were no significant differences between degradation of TPH in the rhizosphere of +P. indica plants in comparison to -P. indica plants.

  18. Deducing hybrid performance from parental metabolic profiles of young primary roots of maize by using a multivariate diallel approach.

    Directory of Open Access Journals (Sweden)

    Kristen Feher

    Full Text Available Heterosis, the greater vigor of hybrids compared to their parents, has been exploited in maize breeding for more than 100 years to produce ever better performing elite hybrids of increased yield. Despite extensive research, the underlying mechanisms shaping the extent of heterosis are not well understood, rendering the process of selecting an optimal set of parental lines tedious. This study is based on a dataset consisting of 112 metabolite levels in young roots of four parental maize inbred lines and their corresponding twelve hybrids, along with the roots' biomass as a heterotic trait. Because the parental biomass is a poor predictor for hybrid biomass, we established a model framework to deduce the biomass of the hybrid from metabolite profiles of its parental lines. In the proposed framework, the hybrid metabolite levels are expressed relative to the parental levels by incorporating the standard concept of additivity/dominance, which we name the Combined Relative Level (CRL. Our modeling strategy includes a feature selection step on the parental levels which are demonstrated to be predictive of CRL across many hybrid metabolites. We demonstrate that these selected parental metabolites are further predictive of hybrid biomass. Our approach directly employs the diallel structure in a multivariate fashion, whereby we attempt to not only predict macroscopic phenotype (biomass, but also molecular phenotype (metabolite profiles. Therefore, our study provides the first steps for further investigations of the genetic determinants to metabolism and, ultimately, growth. Finally, our success on the small-scale experiments implies a valid strategy for large-scale experiments, where parental metabolite profiles may be used together with profiles of selected hybrids as a training set to predict biomass of all possible hybrids.

  19. An investigation on the chemotactic responses of different entomopathogenic nematode strains to mechanically damaged maize root volatile compounds.

    Science.gov (United States)

    Laznik, Z; Trdan, S

    2013-07-01

    Entomopathogenic nematodes (EPNs) respond to a variety of stimuli when foraging. In a laboratory investigation, we tested the chemotactic responses of 8 EPN strains (Steinernema and Heterorhabditis) to three mechanically damaged maize root compounds (linalool, α-caryophyllene and β-caryophyllene). We hypothesized that the EPN directional response to the tested volatile compounds would vary among the species and volatile compound and may be related to foraging strategies. The nematodes with an intermediate foraging strategy (Steinernema feltiae) proved to be less active in their movement toward volatile compounds in a comparison with the ambushers (Steinernema carpocapsae) and cruisers (Steinernema kraussei and Heterorhabditis bacteriophora); β-caryophyllene was found to be the most attractive substance in our experiment. The results of our investigation showed that the cruisers were more attracted to β-caryophyllene than the ambushers and intermediates. The foraging strategy did not affect the movement of the IJs toward the other tested volatile compounds or the control. Our results suggest that the response to different volatile cues is more a strain-specific characteristic than a different host-searching strategy. Only S. carpocapsae strain B49 displayed an attraction to linalool, whereas S. kraussei showed a retarded reaction to β-caryophyllene and α-caryophyllene in our experiment. The EPN strains showed only a weak attraction to α-caryophyllene, suggesting that this volatile compound could not have an important role in the orientation of IJs to the damaged roots of maize plants. These results expand our knowledge of volatile compounds as the cues that may be used by EPNs for finding hosts or other aspects of navigation in the soil. Copyright © 2013 Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

    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.

  1. Hypoxic stress-induced changes in ribosomes of maize seedling roots

    International Nuclear Information System (INIS)

    Bailey-Serres, J.; Freeling, M.

    1990-01-01

    The hypoxic stress response of Zea mays L. seedling roots involves regulation of gene expression at transcriptional and posttranscriptional levels. We investigated the effect of hypoxia on the translational machinery of seedling roots. The levels of monoribosomes and ribosomal subunits increased dramatically within 1 hour of stress. Prolonged hypoxia resulted in continued accumulation of nontranslating ribosomes, as well as increased levels of small polyribosomes. The return of seedlings to normal aerobic conditions resulted in recovery of normal polyribosome levels. Comparison of ribosomal proteins from control and hypoxic roots revealed differences in quantity and electrophoretic mobility. In vivo labeling of roots with [ 35 S]methionine revealed variations in newly synthesized ribosomal proteins. In vivo labeling of roots with [ 32 P]orthophosphate revealed a major reduction in the phosphorylation of a 31 kilodalton ribosomal protein in hypoxic stressed roots. In vitro phosphorylation of ribosomal proteins by endogenous kinases was used to probe for differences in ribosome structure and composition. The patterns of in vitro kinased phosphoproteins of ribosomes from control and hypoxic roots were not identical. Variation in phosphoproteins of polyribosomes from control and hypoxic roots, as well as among polyribosomes from hypoxic roots were observed. These results indicate that modification of the translational machinery occurs in response to hypoxic stress

  2. Distribution of linker histone variants during plant cell differentiation in the developmental zones of the maize root, dedifferentiation in callus culture after auxin treatment

    Directory of Open Access Journals (Sweden)

    ANASTASIOS ALATZAS

    2008-01-01

    Full Text Available Although several linker histone variants have been studied in both animal and plant organisms, little is known about their distribution during processes that involve alterations in chromatin function, such as differentiation, dedifferentiation and hormone treatment. In this study, we identified linker histone variants by using specific anti-histone Hl antibodies. Each variant's ratio to total Hl in the three developmental zones of maize (Zea mays L. root and in callus cultures derived from them was estimated in order to define possible alterations either during plant cell differentiation or during their dedifferentiation. We also evaluated linker histone variants' ratios in the developmental zones of maize roots treated with auxin in order to examine the effects of exogenous applied auxin to linker histone variant distribution. Finally, immunohistochemical detection was used to identify the root tissues containing each variant and correlate them with the physiological status of the plant cells. According to the results presented in this study, linker histone variants' ratios are altered in the developmental zones of maize root, while they are similar to the meristematic zone in samples from callus cultures and to the differentiation zone in samples from roots treated with auxin. We propose that the alterations in linker histone variants' ratios are correlated with plant cell differentiation and dedifferentiation.

  3. Development of a 2D laser ablation inductively coupled plasma mass spectrometry mapping procedure for mercury in maize (Zea mays L.) root cross-sections

    Energy Technology Data Exchange (ETDEWEB)

    Debeljak, Marta [Analytical Chemistry Laboratory, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna Pot 111, SI-1000 Ljubljana (Slovenia); Elteren, Johannes T. van, E-mail: elteren@ki.si [Analytical Chemistry Laboratory, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Vogel-Mikuš, Katarina [Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna Pot 111, SI-1000 Ljubljana (Slovenia)

    2013-07-17

    Graphical abstract: -- Highlights: •LA-ICP-MS mapping to study the distribution of Hg in plant root cross-sections. •Sorption of LA-generated Hg vapour leads to serious memory effects. •Spot analysis with a delay time of 10 s in between spots alleviates memory effects. •Ablation straight through the sample simplifies calibration. •Hg{sup 2+} does not cross the endodermal root barrier of maize plants. -- Abstract: A LA-ICP-MS method based on a 213 nm Nd:YAG laser and a quadrupole ICP-MS has been developed for mapping of mercury in root cross-sections of maize (Zea mays L.) to investigate the mechanism of mercury uptake from soil and its potential translocation to the edible parts. Conventional rastering was found to be unusable due to sorption of mercury onto the internal parts of the LA device, giving rising to memory effects resulting in serious loss of resolution and inaccurate quantification. Spot analysis on a virtual grid on the surface of the root sections using washout times of 10 s in between spots greatly alleviated problems related to these memory effects. By ablating straight through the root sections on a poly(methyl methacrylate) support the calibration process was simplified as internal standardization and matrix-matching could be circumvented. Mercury-spiked freeze-drying embedding medium, sectioned similarly to the root sections, was used for the preparation of the standards. Standards and root sections were subjected to spot analysis using the following operational parameters: beam diameter, 15 μm; laser fluence, 2.5 J cm{sup −2}; repetition rate, 20 Hz; dwell time, 1 s; acquisition time, 0.1 s. The mercury peaks for standards and roots sections could be consistently integrated for quantification and construction of the 2D mercury maps for the root sections. This approach was successfully used to investigate the mercury distribution in root sections of maize grown in soil spiked to a level of 50 mg kg{sup −1} DW HgCl{sub 2}. It was

  4. Development of a 2D laser ablation inductively coupled plasma mass spectrometry mapping procedure for mercury in maize (Zea mays L.) root cross-sections

    International Nuclear Information System (INIS)

    Debeljak, Marta; Elteren, Johannes T. van; Vogel-Mikuš, Katarina

    2013-01-01

    Graphical abstract: -- Highlights: •LA-ICP-MS mapping to study the distribution of Hg in plant root cross-sections. •Sorption of LA-generated Hg vapour leads to serious memory effects. •Spot analysis with a delay time of 10 s in between spots alleviates memory effects. •Ablation straight through the sample simplifies calibration. •Hg 2+ does not cross the endodermal root barrier of maize plants. -- Abstract: A LA-ICP-MS method based on a 213 nm Nd:YAG laser and a quadrupole ICP-MS has been developed for mapping of mercury in root cross-sections of maize (Zea mays L.) to investigate the mechanism of mercury uptake from soil and its potential translocation to the edible parts. Conventional rastering was found to be unusable due to sorption of mercury onto the internal parts of the LA device, giving rising to memory effects resulting in serious loss of resolution and inaccurate quantification. Spot analysis on a virtual grid on the surface of the root sections using washout times of 10 s in between spots greatly alleviated problems related to these memory effects. By ablating straight through the root sections on a poly(methyl methacrylate) support the calibration process was simplified as internal standardization and matrix-matching could be circumvented. Mercury-spiked freeze-drying embedding medium, sectioned similarly to the root sections, was used for the preparation of the standards. Standards and root sections were subjected to spot analysis using the following operational parameters: beam diameter, 15 μm; laser fluence, 2.5 J cm −2 ; repetition rate, 20 Hz; dwell time, 1 s; acquisition time, 0.1 s. The mercury peaks for standards and roots sections could be consistently integrated for quantification and construction of the 2D mercury maps for the root sections. This approach was successfully used to investigate the mercury distribution in root sections of maize grown in soil spiked to a level of 50 mg kg −1 DW HgCl 2 . It was found that at given

  5. Spatiotemporal variation of nitrate uptake kinetics within the maize (Zea mays L.) root system is associated with greater nitrate uptake and interactions with architectural phenes.

    Science.gov (United States)

    York, Larry M; Silberbush, Moshe; Lynch, Jonathan P

    2016-06-01

    Increasing maize nitrogen acquisition efficiency is a major goal for the 21st century. Nitrate uptake kinetics (NUK) are defined by I max and K m, which denote the maximum uptake rate and the affinity of transporters, respectively. Because NUK have been studied predominantly at the molecular and whole-root system levels, little is known about the functional importance of NUK variation within root systems. A novel method was created to measure NUK of root segments that demonstrated variation in NUK among root classes (seminal, lateral, crown, and brace). I max varied among root class, plant age, and nitrate deprivation combinations, but was most affected by plant age, which increased I max, and nitrate deprivation time, which decreased I max K m was greatest for crown roots. The functional-structural simulation SimRoot was used for sensitivity analysis of plant growth to root segment I max and K m, as well as to test interactions of I max with root system architectural phenes. Simulated plant growth was more sensitive to I max than K m, and reached an asymptote near the maximum I max observed in the empirical studies. Increasing the I max of lateral roots had the largest effect on shoot growth. Additive effects of I max and architectural phenes on nitrate uptake were observed. Empirically, only lateral root tips aged 20 d operated at the maximum I max, and simulations demonstrated that increasing all seminal and lateral classes to this maximum rate could increase plant growth by as much as 26%. Therefore, optimizing I max for all maize root classes merits attention as a promising breeding goal. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  6. Identification of QTLs for root characteristics in maize grown in hydroponics and analysis of their overlap with QTLs for grain yield in the field at two water regimes.

    Science.gov (United States)

    Tuberosa, Roberto; Sanguineti, Maria Corinna; Landi, Pierangelo; Giuliani, Marcella Michela; Salvi, Silvio; Conti, Sergio

    2002-01-01

    We investigated the overlap among quantitative trait loci (QTLs) in maize for seminal root traits measured in hydroponics with QTLs for grain yield under well-watered (GY-WW) and water-stressed (GY-WS) field conditions as well as for a drought tolerance index (DTI) computed as GY-WS/GY-WW. In hydroponics, 11, 7, 9, and 10 QTLs were identified for primary root length (R1L), primary root diameter (R1D), primary root weight (R1W), and for the weight of the adventitious seminal roots (R2W), respectively. In the field, 7, 8, and 9 QTLs were identified for GY-WW, GY-WS, and DTI, respectively. Despite the weak correlation of root traits in hydroponics with GY-WW, GY-WS, and DTI, a noticeable overlap between the corresponding QTLs was observed. QTLs for R2W most frequently and consistently overlapped with QTLs for GY-WW, GY-WS, and/or DTI. At four QTL regions, an increase in R2W was positively associated with GY-WW, GY-WS, and/or DTI. A 10 cM interval on chromosome 1 between PGAMCTA205 and php20644 showed the strongest effect on R1L, R1D, R2W, GY-WW, GY-WS, and DTI. These results indicate the feasibility of using hydroponics in maize to identify QTL regions controlling root traits at an early growth stage and also influencing GY in the field. A comparative analysis of the QTL regions herein identified with those described in previous studies investigating root traits in different maize populations revealed a number of QTLs in common.

  7. Partitioning between primary and secondary metabolism of carbon allocated to roots in four maize genotypes under water deficit and its effects on productivity

    Directory of Open Access Journals (Sweden)

    Alyne Oliveira Lavinsky

    2015-10-01

    Full Text Available Plants may respond to drought by altering biomass allocation to shoots and roots or by changing the metabolic activities in these organs. To determine how drought changes the partitioning of carbon allocated to growth and secondary metabolism in maize roots and how it affects photosynthesis (A and productivity in maize, we evaluated leaf gas exchange, yield componentes, root morphology, and primary and secondary metabolites including total soluble sugars (TSS, starch (S, phenolics (PHE, and lignin (LIG. Data were collected from pot-grown plants of four maize genotypes: BRS 1010 and 2B710 (sensitive genotypes and DKB390 and BRS1055 (tolerant genotypes under two soil water tensions: field capacity (FC, − 18 kPa and water deficit (WD, − 138 kPa. WD was applied at the pre-flowering stage for 12 days and then the water supply was restored and maintained at optimum levels until the end of the cycle. For genotype BRS 1055 under FC, the greatest A did not result in greater grain biomass (DGB because the accumulated photoassimilates had already filled the cells, and thus the excessive TSS synthesized in leaves was allocated to roots in large amounts. However, the sharp decrease in A caused by WD imposition in this genotype did not affect the influx pressure of leaf TSS, which was due largely to conversion of primary metabolites to PHE compounds to increase the length of fine roots. In leaves of DKB390 under WD, both S and TSS were reduced, whereas PHE were increased to prevent excessive water loss and xylem cavitation. Under WD, both BRS1010 and 2B710 genotypes displayed reduced allocation of biomass to shoots and roots and LIG content in leaves, as well as lower A and DGB values. In BRS1010 this response was coupled to S decrease in leaves and TSS increase in roots, whereas in 2B710 there was a concomitant S increase in roots.

  8. Transcriptomic changes during maize roots development responsive to Cadmium (Cd) pollution using comparative RNAseq-based approach

    International Nuclear Information System (INIS)

    Peng, Hua; He, Xiujing; Gao, Jian; Ma, Haixia; Zhang, Zhiming; Shen, Yaou; Pan, Guangtang; Lin, Haijian

    2015-01-01

    The heavy metal cadmium (Cd), acts as a widespread environmental contaminant, which has shown to adversely affect human health, food safety and ecosystem safety in recent years. However, research on how plant respond to various kinds of heavy metal stress is scarcely reported, especially for understanding of complex molecular regulatory mechanisms and elucidating the gene networks of plant respond to Cd stress. Here, transcriptomic changes during Mo17 and B73 seedlings development responsive to Cd pollution were investigated and comparative RNAseq-based approach in both genotypes were performed. 115 differential expression genes (DEGs) with significant alteration in expression were found co-modulated in both genotypes during the maize seedling development; of those, most of DGEs were found comprised of stress and defense responses proteins, transporters, as well as transcription factors, such as thaumatin-like protein, ZmOPR2 and ZmOPR5. More interestingly, genotype-specific transcriptional factors changes induced by Cd stress were found contributed to the regulatory mechanism of Cd sensitivity in both different genotypes. Moreover, 12 co-expression modules associated with specific biological processes or pathways (M1 to M12) were identified by consensus co-expression network. These results will expand our understanding of complex molecular mechanism of response and defense to Cd exposure in maize seedling roots. - Highlights: • Transcriptomic changes responsive to Cd pollution using comparative RNAseq-based approach. • 115 differential expression genes (DEGs) were found co-modulated in both genotypes. • Most of DGEs belong to stress and defense responses proteins, transporters, transcription factors. • 12 co-expression modules associated with specific biological processes or pathways. • Genotype-specific transcriptional factors changes induced by Cd stress were found

  9. Transcriptomic changes during maize roots development responsive to Cadmium (Cd) pollution using comparative RNAseq-based approach

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Hua [Key Laboratory of Biology and Genetic Improvement of Maize in Southwest Region, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Wenjiang, Sichuan, 611130 (China); Sichuan Tourism College, Chengdu, 610000, Sichuan (China); He, Xiujing [Key Laboratory of Biology and Genetic Improvement of Maize in Southwest Region, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Wenjiang, Sichuan, 611130 (China); Gao, Jian [Institute of Pathology and Southwest Cancer Center, Southwest Hospital, Third Military Medical University, Key Laboratory of Tumor Immunopathology, Ministry of Education of China, Chongqing (China); Ma, Haixia; Zhang, Zhiming; Shen, Yaou [Key Laboratory of Biology and Genetic Improvement of Maize in Southwest Region, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Wenjiang, Sichuan, 611130 (China); Pan, Guangtang, E-mail: pangt@sicau.edu.cn [Key Laboratory of Biology and Genetic Improvement of Maize in Southwest Region, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Wenjiang, Sichuan, 611130 (China); Lin, Haijian, E-mail: linhj521@gmail.com [Key Laboratory of Biology and Genetic Improvement of Maize in Southwest Region, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Wenjiang, Sichuan, 611130 (China)

    2015-09-04

    The heavy metal cadmium (Cd), acts as a widespread environmental contaminant, which has shown to adversely affect human health, food safety and ecosystem safety in recent years. However, research on how plant respond to various kinds of heavy metal stress is scarcely reported, especially for understanding of complex molecular regulatory mechanisms and elucidating the gene networks of plant respond to Cd stress. Here, transcriptomic changes during Mo17 and B73 seedlings development responsive to Cd pollution were investigated and comparative RNAseq-based approach in both genotypes were performed. 115 differential expression genes (DEGs) with significant alteration in expression were found co-modulated in both genotypes during the maize seedling development; of those, most of DGEs were found comprised of stress and defense responses proteins, transporters, as well as transcription factors, such as thaumatin-like protein, ZmOPR2 and ZmOPR5. More interestingly, genotype-specific transcriptional factors changes induced by Cd stress were found contributed to the regulatory mechanism of Cd sensitivity in both different genotypes. Moreover, 12 co-expression modules associated with specific biological processes or pathways (M1 to M12) were identified by consensus co-expression network. These results will expand our understanding of complex molecular mechanism of response and defense to Cd exposure in maize seedling roots. - Highlights: • Transcriptomic changes responsive to Cd pollution using comparative RNAseq-based approach. • 115 differential expression genes (DEGs) were found co-modulated in both genotypes. • Most of DGEs belong to stress and defense responses proteins, transporters, transcription factors. • 12 co-expression modules associated with specific biological processes or pathways. • Genotype-specific transcriptional factors changes induced by Cd stress were found.

  10. Cadmium spiked soil modulates root organic acids exudation and ionic contents of two differentially Cd tolerant maize (Zea mays L.) cultivars.

    Science.gov (United States)

    Javed, M Tariq; Akram, M Sohail; Tanwir, Kashif; Javed Chaudhary, Hassan; Ali, Qasim; Stoltz, Eva; Lindberg, Sylvia

    2017-07-01

    Our earlier work described that the roots of two maize cultivars, grown hydroponically, differentially responded to cadmium (Cd) stress by initiating changes in medium pH depending on their Cd tolerance. The current study investigated the root exudation, elemental contents and antioxidant behavior of the same maize cultivars [cv. 3062 (Cd-tolerant) and cv. 31P41 (Cd-sensitive)] under Cd stress. Plants were maintained in a rhizobox-like system carrying soil spiked with Cd concentrations of 0, 10, 20, 30, 40 and 50 μmol/kg soil. The root and shoot Cd contents increased, while Mg, Ca and Fe contents mainly decreased at higher Cd levels, and preferentially in the sensitive cultivar. Interestingly, the K contents increased in roots of cv. 3062 at low Cd treatments. The Cd stress caused acidosis of the maize root exudates predominantly in cv. 3062. The concentration of various organic acids was significantly increased in the root exudates of cv. 3062 with applied Cd levels. This effect was diminished in cv. 31P41 at higher Cd levels. Cd exposure increased the relative membrane permeability, anthocyanin (only in cv. 3062), proline contents and the activities of peroxidases (POD) and superoxide dismutase (SOD). The only exception was the catalase activity, which was diminished in both cultivars. Root Cd contents were positively correlated with the secretion of acetic acid, oxalic acid, glutamic acid, citric acid, and succinic acid. The antioxidants like POD and SOD exhibited a positive correlation with the organic acids under Cd stress. It is likly that a high exudation of dicarboxylic organic acids improves nutrient uptake and activities of antioxidants, which enables the tolerant cultivar to acclimatize in Cd polluted environment. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Characterization of mature maize (Zea mays L.) root system architecture and complexity in a diverse set of Ex-PVP inbreds and hybrids.

    Science.gov (United States)

    Hauck, Andrew L; Novais, Joana; Grift, Tony E; Bohn, Martin O

    2015-01-01

    The mature root system is a vital plant organ, which is critical to plant performance. Commercial maize (Zea mays L.) breeding has resulted in a steady increase in plant performance over time, along with noticeable changes in above ground vegetative traits, but the corresponding changes in the root system are not presently known. In this study, roughly 2500 core root systems from field trials of a set of 10 diverse elite inbreds formerly protected by Plant Variety Protection plus B73 and Mo17 and the 66 diallel intercrosses among them were evaluated for root traits using high throughput image-based phenotyping. Overall root architecture was modeled by root angle (RA) and stem diameter (SD), while root complexity, the amount of root branching, was quantified using fractal analysis to obtain values for fractal dimension (FD) and fractal abundance (FA). For each trait, per se line effects were highly significant and the most important contributor to trait performance. Mid-parent heterosis and specific combining ability was also highly significant for FD, FA, and RA, while none of the traits showed significant general combining ability. The interaction between the environment and the additive line effect was also significant for all traits. Within the inbred and hybrid generations, FD and FA were highly correlated (rp ≥ 0.74), SD was moderately correlated to FD and FA (0.69 ≥ rp ≥ 0.48), while the correlation between RA and other traits was low (0.13 ≥ rp ≥ -0.40). Inbreds with contrasting effects on complexity and architecture traits were observed, suggesting that root complexity and architecture traits are inherited independently. A more comprehensive understanding of the maize root system and the way it interacts with the environment will be useful for defining adaptation to nutrient acquisition and tolerance to stress from drought and high plant densities, critical factors in the yield gains of modern hybrids.

  12. Histone acetylation associated up-regulation of the cell wall related genes is involved in salt stress induced maize root swelling

    OpenAIRE

    Li, Hui; Yan, Shihan; Zhao, Lin; Tan, Junjun; Zhang, Qi; Gao, Fei; Wang, Pu; Hou, Haoli; Li, Lijia

    2014-01-01

    Background Salt stress usually causes crop growth inhibition and yield decrease. Epigenetic regulation is involved in plant responses to environmental stimuli. The epigenetic regulation of the cell wall related genes associated with the salt-induced cellular response is still little known. This study aimed to analyze cell morphological alterations in maize roots as a consequence of excess salinity in relation to the transcriptional and epigenetic regulation of the cell wall related protein ge...

  13. A maize introgression library reveals ample genetic variability for root architecture, water use efficiency and grain yield under different water regimes

    OpenAIRE

    Salvi, S.; Giuliani, S.; Cané, M.; Sciara, G.; Bovina, R.; Welcker, Claude; Cabrera Bosquet, Llorenç; Grau, Antonin; Tardieu, Francois; Meriggi, P.

    2015-01-01

    The genetic dissection of root system architecture (RSA) provides valuable opportunities towards a better understanding of its role in determining yield under different water regimes. To this end, a maize introgression library comprised of 75 BC5 lines derived from the cross between Gaspé Flint (an early line; donor parent) and B73 (an elite line; recurrent parent) were evaluated in two experiments conducted under well-watered and water-deficit conditions (WW and WD, respectively) in order to...

  14. Maize and prairie root contributions to soil CO2 emissions in the field

    Science.gov (United States)

    Background and aims: A major hurdle in closing carbon budgets is partitioning soil-surface CO2 fluxes by source. This study aims to estimate CO2 resulting from root growth (RG) in the field. Methods: We used periodic 48-hour shading over two seasons to estimate and compare RG-derived CO2 in one annu...

  15. A maize root tip system to study DNA replication programmes in somatic and endocycling nuclei during plant development.

    Science.gov (United States)

    Bass, Hank W; Wear, Emily E; Lee, Tae-Jin; Hoffman, Gregg G; Gumber, Hardeep K; Allen, George C; Thompson, William F; Hanley-Bowdoin, Linda

    2014-06-01

    The progress of nuclear DNA replication is complex in both time and space, and may reflect several levels of chromatin structure and 3-dimensional organization within the nucleus. To understand the relationship between DNA replication and developmental programmes, it is important to examine replication and nuclear substructure in different developmental contexts including natural cell-cycle progressions in situ. Plant meristems offer an ideal opportunity to analyse such processes in the context of normal growth of an organism. Our current understanding of large-scale chromosomal DNA replication has been limited by the lack of appropriate tools to visualize DNA replication with high resolution at defined points within S phase. In this perspective, we discuss a promising new system that can be used to visualize DNA replication in isolated maize (Zea mays L.) root tip nuclei after in planta pulse labelling with the thymidine analogue, 5-ethynyl-2'-deoxyuridine (EdU). Mixed populations of EdU-labelled nuclei are then separated by flow cytometry into sequential stages of S phase and examined directly using 3-dimensional deconvolution microscopy to characterize spatial patterns of plant DNA replication. Combining spatiotemporal analyses with studies of replication and epigenetic inheritance at the molecular level enables an integrated experimental approach to problems of mitotic inheritance and cellular differentiation. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  16. Paenibacillus nebraskensis sp. nov., isolated from the root surface of field-grown maize.

    Science.gov (United States)

    Kämpfer, Peter; Busse, Hans-Jürgen; McInroy, John A; Hu, Chia-Hui; Kloepper, Joseph W; Glaeser, Stefanie P

    2017-12-01

    A Gram-positive-staining, aerobic, non-endospore-forming bacterial strain (JJ-59 T ), isolated from a field-grown maize plant in Dunbar, Nebraska in 2014 was studied by a polyphasic approach. Based on 16S rRNA gene sequence similarity comparisons, strain JJ-59 T was shown to be a member of the genus Paenibacillus, most closely related to the type strains of Paenibacillus aceris (98.6 % 16S rRNA gene sequence similarity) and Paenibacillus chondroitinus (97.8 %). For all other type strains of species of the genus Paenibacillus lower 16S rRNA gene sequence similarities were obtained. DNA-DNA hybridization values of strain JJ-59 T to the type strains of P. aceris and P. chondroitinus were 26 % (reciprocal, 59 %) and 52 % (reciprocal, 59 %), respectively. Chemotaxonomic characteristics such as the presence of meso-diaminopimelic acid in the peptidoglycan, the major quinone MK-7 and spermidine as the major polyamine were in agreement with the characteristics of the genus Paenibacillus. Strain JJ-59 T shared with its next related species P. aceris the major lipids diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an unidentified aminophospholipid, but the presence/absence of certain lipids was clearly distinguishable. Major fatty acids of strain JJ-59 T were anteiso-C15 : 0, iso-C15 : 0 and iso-C16 : 0, and the genomic G+C content is 47.2 mol%. Physiological and biochemical characteristics of strain JJ-59 T were clearly different from the most closely related species of the genus Paenibacillus. Thus, strain JJ-59 T represents a novel species of the genus Paenibacillus, for which the name Paenibacillus nebraskensis sp. nov. is proposed, with JJ-59 T (=DSM 103623 T =CIP 111179 T =LMG 29764 T ) as the type strain.

  17. Roothairless5, which functions in maize (Zea mays L.) root hair initiation and elongation encodes a monocot-specific NADPH oxidase.

    Science.gov (United States)

    Nestler, Josefine; Liu, Sanzhen; Wen, Tsui-Jung; Paschold, Anja; Marcon, Caroline; Tang, Ho Man; Li, Delin; Li, Li; Meeley, Robert B; Sakai, Hajime; Bruce, Wesley; Schnable, Patrick S; Hochholdinger, Frank

    2014-09-01

    Root hairs are instrumental for nutrient uptake in monocot cereals. The maize (Zea mays L.) roothairless5 (rth5) mutant displays defects in root hair initiation and elongation manifested by a reduced density and length of root hairs. Map-based cloning revealed that the rth5 gene encodes a monocot-specific NADPH oxidase. RNA-Seq, in situ hybridization and qRT-PCR experiments demonstrated that the rth5 gene displays preferential expression in root hairs but also accumulates to low levels in other tissues. Immunolocalization detected RTH5 proteins in the epidermis of the elongation and differentiation zone of primary roots. Because superoxide and hydrogen peroxide levels are reduced in the tips of growing rth5 mutant root hairs as compared with wild-type, and Reactive oxygen species (ROS) is known to be involved in tip growth, we hypothesize that the RTH5 protein is responsible for establishing the high levels of ROS in the tips of growing root hairs required for elongation. Consistent with this hypothesis, a comparative RNA-Seq analysis of 6-day-old rth5 versus wild-type primary roots revealed significant over-representation of only two gene ontology (GO) classes related to the biological functions (i.e. oxidation/reduction and carbohydrate metabolism) among 893 differentially expressed genes (FDR <5%). Within these two classes the subgroups 'response to oxidative stress' and 'cellulose biosynthesis' were most prominently represented. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

  18. Variable Levels of Glutathione S-Transferases Are Responsible for the Differential Tolerance to Metolachlor between Maize (Zea mays) Shoots and Roots.

    Science.gov (United States)

    Li, Dongzhi; Xu, Li; Pang, Sen; Liu, Zhiqian; Wang, Kai; Wang, Chengju

    2017-01-11

    Glutathione S-transferases (GSTs) play important roles in herbicide tolerance. However, studies on GST function in herbicide tolerance among plant tissues are still lacking. To explore the mechanism of metolachlor tolerance difference between maize shoots and roots, the effects of metolachlor on growth, GST activity, and the expression of the entire GST gene family were investigated. It was found that this differential tolerance to metolachlor was correlated with contrasting GST activity between the two tissues and can be eliminated by a GST inhibitor. An in vitro metolachlor-glutathione conjugation assay confirmed that the transformation of metolachlor is 2-fold faster in roots than in shoots. The expression analysis of the GST gene family revealed that most GST genes are expressed much higher in roots than shoots, both in control and in metolachlor-treated plants. Taken together, higher level expression of most GST genes, leading to higher GST activity and faster herbicide transformation, appears to be responsible for the higher tolerance to metolachlor of maize roots than shoots.

  19. Performance and meat quality characteristics of broilers fed fermented mixture of grated cassava roots and palm kernel cake as replacement for maize.

    Science.gov (United States)

    Chukwukaelo, A K; Aladi, N O; Okeudo, N J; Obikaonu, H O; Ogbuewu, I P; Okoli, I C

    2018-03-01

    Performance and meat quality characteristics of broilers fed fermented mixture of grated cassava roots and palm kernel cake (FCP-mix) as a replacement for maize were studied. One hundred and eighty (180), 7-day-old broiler chickens were divided into six groups of 30 birds, and each group replicated thrice. Six experimental diets were formulated for both starter and finisher stages with diets 1 and 6 as controls. Diet 1 contained maize whereas diet 6 contained a 1:1 mixture of cassava root meal (CRM) and palm kernel cake (PKC). In diets 2, 3, 4, and 5, the FCP-mix replaced maize at the rate of 25, 50, 75, and 100%, respectively. Each group was assigned to one experimental diet in a completely randomized design. The proximate compositions of the diets were evaluated. Live weight, feed intake, feed conversion ratio (FCR), carcass weight, and sensory attributes of the meats were obtained from each replicate and data obtained was analyzed statistically. The results showed that live weight, average daily weight gain (ADWG), average daily feed intake (ADFI), and FCR of birds on treatment diets were better than those on the control diets (Diets 1 and 6). The feed cost per kilogram weight gained decreased with inclusion levels of FCP-mix. Birds on diet 1 recorded significantly (p  0.05) affected by the inclusion of FCP-mix in the diets. FCP-mix is a suitable substitute for maize in broiler diet at a replacement level of up to 100% for best live weight, carcass weight yield, and meat quality.

  20. In vitro oxidation of indoleacetic acid by soluble auxin-oxidases and peroxidases from maize roots

    International Nuclear Information System (INIS)

    Beffa, R.; Martin, H.V.; Pilet, P.E.

    1990-01-01

    Soluble auxin-oxidases were extracted from Zea mays L. cv LG11 apical root segments and partially separated from peroxidases (EC 1.11.1.7) by size-exclusion chromatography. Auxin-oxidases were resolved into one main peak corresponding to a molecular mass of 32.5 kilodaltons and a minor peak at 54.5 kilodaltons. Peroxidases were separated into at least four peaks, with molecular masses from 32.5 to 78 kilodaltons. In vitro activity of indoleacetic acid-oxidases was dependent on the presence of MnCl 2 and p-coumaric acid. Compound(s) present in the crude extract and several synthetic auxin transport inhibitors (including 2,3,5-triiodobenzoic acid and N-1-naphthylphthalamic acid) inhibited auxin-oxidase activity, but had no effect on peroxidases. The products resulting from the in vitro enzymatic oxidation of [ 3 H]indoleacetic acid were separated by HPLC and the major metabolite was found to cochromatograph with indol-3yl-methanol

  1. In Azospirillum brasilense, mutations in flmA or flmB genes affect polar flagellum assembly, surface polysaccharides, and attachment to maize roots.

    Science.gov (United States)

    Rossi, Fernando Ariel; Medeot, Daniela Beatriz; Liaudat, Juan Pablo; Pistorio, Mariano; Jofré, Edgardo

    2016-09-01

    Azospirillum brasilense is a soil bacterium capable of promoting plant growth. Several surface components were previously reported to be involved in the attachment of A. brasilense to root plants. Among these components are the exopolysaccharide (EPS), lipopolysaccharide (LPS) and the polar flagellum. Flagellin from polar flagellum is glycosylated and it was suggested that genes involved in such a posttranslational modification are the same ones involved in the biosynthesis of sugars present in the O-antigen of the LPS. In this work, we report on the characterization of two homologs present in A. brasilense Cd, to the well characterized flagellin modification genes, flmA and flmB, from Aeromonas caviae. We show that mutations in either flmA or flmB genes of A. brasilense resulted in non-motile cells due to alterations in the polar flagellum assembly. Moreover, these mutations also affected the capability of A. brasilense cells to adsorb to maize roots and to produce LPS and EPS. By generating a mutant containing the polar flagellum affected in their rotation, we show the importance of the bacterial motility for the early colonization of maize roots. Copyright © 2016 Elsevier GmbH. All rights reserved.

  2. Arbuscular mycorrhizal fungal diversity, root colonization, and soil alkaline phosphatase activity in response to maize-wheat rotation and no-tillage in North China.

    Science.gov (United States)

    Hu, Junli; Yang, Anna; Zhu, Anning; Wang, Junhua; Dai, Jue; Wong, Ming Hung; Lin, Xiangui

    2015-07-01

    Monitoring the effects of no-tillage (NT) in comparison with conventional tillage (CT) on soil microbes could improve our understanding of soil biochemical processes and thus help us to develop sound management strategies. The objective of this study was to compare the species composition and ecological function of soil arbuscular mycorrhizal (AM) fungi during the growth and rotation of crops under NT and CT. From late June 2009 to early June 2010, 32 topsoil (0-15 cm) samples from four individual plots per treatment (CT and NT) were collected at both the jointing and maturation stages of maize (Zea mays L.) and wheat (Triticum aestivum L.) from a long-term experimental field that was established in an Aquic Inceptisol in North China in June 2006. The AM fungal spores were isolated and identified and then used to calculate species diversity indices, including the Shannon- Wiener index (H'), Evenness (E), and Simpson's index (D). The root mycorrhizal colonization and soil alkaline phosphatase activity were also determined. A total of 34 species of AM fungi within nine genera were recorded. Compared with NT, CT negatively affected the soil AM fungal community at the maize sowing stage, leading to decreases in the average diversity indices (from 2.12, 0.79, and 0.82 to 1.79, 0.72, and 0.74 for H', E, and D, respectively), root mycorrhizal colonization (from 28% to 20%), soil alkaline phosphatase activity (from 0.24 to 0.19 mg/g/24 h) and available phosphorus concentration (from 17.4 to 10.5 mg/kg) at the maize jointing stage. However, reductions in diversity indices of H', E, and D were restored to 2.20, 0.81, and 0.84, respectively, at the maize maturation stage. CT should affect the community again at the wheat sowing stage; however, a similar restoration in the species diversity of AM fungi was completed before the wheat jointing stage, and the highest Jaccard index (0.800) for similarity in the species composition of soil AM fungi between CT and NT was recorded at

  3. Phosphorus acquisition efficiency in arbuscular mycorrhizal maize is correlated with the abundance of root-external hyphae and the accumulation of transcripts encoding PHT1 phosphate transporters.

    Science.gov (United States)

    Sawers, Ruairidh J H; Svane, Simon F; Quan, Clement; Grønlund, Mette; Wozniak, Barbara; Gebreselassie, Mesfin-Nigussie; González-Muñoz, Eliécer; Chávez Montes, Ricardo A; Baxter, Ivan; Goudet, Jerome; Jakobsen, Iver; Paszkowski, Uta

    2017-04-01

    Plant interactions with arbuscular mycorrhizal fungi have long attracted interest for their potential to promote more efficient use of mineral resources in agriculture. Their use, however, remains limited by a lack of understanding of the processes that determine the outcome of the symbiosis. In this study, the impact of host genotype on growth response to mycorrhizal inoculation was investigated in a panel of diverse maize lines. A panel of 30 maize lines was evaluated with and without inoculation with arbuscular mycorrhizal fungi. The line Oh43 was identified to show superior response and, along with five other reference lines, was characterized in greater detail in a split-compartment system, using 33 P to quantify mycorrhizal phosphorus uptake. Changes in relative growth indicated variation in host capacity to profit from the symbiosis. Shoot phosphate content, abundance of root-internal and -external fungal structures, mycorrhizal phosphorus uptake, and accumulation of transcripts encoding plant PHT1 family phosphate transporters varied among lines. Superior response in Oh43 is correlated with extensive development of root-external hyphae, accumulation of specific Pht1 transcripts and high phosphorus uptake by mycorrhizal plants. The data indicate that host genetic factors influence fungal growth strategy with an impact on plant performance. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  4. Real-time PCR quantification of the plant growth promoting bacteria Herbaspirillum seropedicae strain SmR1 in maize roots.

    Science.gov (United States)

    Pereira, Tomás Pellizzaro; do Amaral, Fernanda Plucani; Dall'Asta, Pamela; Brod, Fábio Cristiano Angonesi; Arisi, Ana Carolina Maisonnave

    2014-07-01

    The plant growth promoting bacteria Herbaspirillum seropedicae SmR1 is an endophytic diazotroph found in several economically important crops. Considering that methods to monitor the plant-bacteria interaction are required, our objective was to develop a real-time PCR method for quantification of PGPB H. seropedicae in the rhizosphere of maize seedlings. Primer pairs were designed, and their specificity was verified using DNA from 12 different bacterial species. Ten standard curves of qPCR assay using HERBAS1 primers and tenfold serial dilutions of H. seropedicae SmR1 DNA were performed, and PCR efficiency of 91 % and correlation coefficient of 0.99 were obtained. H. seropedicae SmR1 limit of detection was 10(1) copies (corresponding to 60.3 fg of bacterial DNA). qPCR assay using HERBAS1 was used to detect and quantify H. seropedicae strain SmR1 in inoculated maize roots, cultivated in vitro and in pots, harvested 1, 4, 7, and 10 days after inoculation. The estimated bacterial DNA copy number per gram of root was in the range 10(7)-10(9) for plants grown in vitro and it was around 10(6) for plants grown in pots. Primer pair HERBAS1 was able to quantify H. seropedicae SmR1, and this assay can be useful for monitoring plant-bacteria interaction.

  5. 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.

  6. Cytoplasmic pH dynamics in maize pulvinal cells induced by gravity vector changes

    Science.gov (United States)

    Johannes, E.; Collings, D. A.; Rink, J. C.; Allen, N. S.; Brown, C. S. (Principal Investigator)

    2001-01-01

    In maize (Zea mays) and other grasses, changes in orientation of stems are perceived by pulvinal tissue, which responds to the stimulus by differential growth resulting in upward bending of the stem. The amyloplast-containing bundle sheath cells are the sites of gravity perception, although the initial steps of gravity perception and transmission remain unclear. In columella cells of Arabidopsis roots, we previously found that cytoplasmic pH (pH(c)) is a mediator in early gravitropic signaling (A.C. Scott, N.S. Allen [1999] Plant Physiol 121: 1291-1298). The question arises whether pH(c) has a more general role in signaling gravity vector changes. Using confocal ratiometric imaging and the fluorescent pH indicator carboxy seminaphtorhodafluor acetoxymethyl ester acetate, we measured pH(c) in the cells composing the maize pulvinus. When stem slices were gravistimulated and imaged on a horizontally mounted confocal microscope, pH(c) changes were only apparent within the bundle sheath cells, and not in the parenchyma cells. After turning, cytoplasmic acidification was observed at the sides of the cells, whereas the cytoplasm at the base of the cells where plastids slowly accumulated became more basic. These changes were most apparent in cells exhibiting net amyloplast sedimentation. Parenchyma cells and isolated bundle sheath cells did not show any gravity-induced pH(c) changes although all cell types responded to external stimuli in the predicted way: Propionic acid and auxin treatments induced acidification, whereas raising the external pH caused alkalinization. The results suggest that pH(c) has an important role in the early signaling pathways of maize stem gravitropism.

  7. Various forms of organic and inorganic P fertilizers did not negatively affect soil- and root-inhabiting AM fungi in a maize-soybean rotation system.

    Science.gov (United States)

    Beauregard, M S; Gauthier, M-P; Hamel, C; Zhang, T; Welacky, T; Tan, C S; St-Arnaud, M

    2013-02-01

    Arbuscular mycorrhizal (AM) fungi are key components of most agricultural ecosystems. Therefore, understanding the impact of agricultural practices on their community structure is essential to improve nutrient mobilization and reduce plant stress in the field. The effects of five different organic or mineral sources of phosphorus (P) for a maize-soybean rotation system on AM fungal diversity in roots and soil were assessed over a 3-year period. Total DNA was extracted from root and soil samples collected at three different plant growth stages. An 18S rRNA gene fragment was amplified and taxa were detected and identified using denaturing gradient gel electrophoresis followed by sequencing. AM fungal biomass was estimated by fatty acid methyl ester analysis. Soil P fertility parameters were also monitored and analyzed for possible changes related with fertilization or growth stages. Seven AM fungal ribotypes were detected. Fertilization significantly modified soil P flux, but had barely any effect on AM fungi community structure or biomass. There was no difference in the AM fungal community between plant growth stages. Specific ribotypes could not be significantly associated to P treatment. Ribotypes were associated with root or soil samples with variable detection frequencies between seasons. AM fungal biomass remained stable throughout the growing seasons. This study demonstrated that roots and soil host distinct AM fungal communities and that these are very temporally stable. The influence of contrasting forms of P fertilizers was not significant over 3 years of crop rotation.

  8. Morphological plasticity of root growth under mild water stress increases water use efficiency without reducing yield in maize

    NARCIS (Netherlands)

    Cai, Qian; Zhang, Yulong; Sun, Zhanxiang; Zheng, Jiaming; Bai, Wei; Zhang, Yue; Yang, Liu; Feng, Liangshan; Feng, Chen; Zhang, Zhe; Yang, Ning; Evers, Jochem; Zhang, Lizhen

    2017-01-01

    A large yield gap exists in rain-fed maize (Zea mays L.) production in semi-arid regions, mainly caused by frequent droughts halfway through the crop-growing period due to uneven distribution of rainfall. It is questionable whether irrigation systems are economically required in such a region

  9. Cellulase from Trichoderma harzianum interacts with roots and triggers induced systemic resistance to foliar disease in maize

    Science.gov (United States)

    Saravanakumar, Kandasamy; Fan, Lili; Fu, Kehe; Yu, Chuanjin; Wang, Meng; Xia, Hai; Sun, Jianan; Li, Yaqian; Chen, Jie

    2016-01-01

    Trichoderma harzianum is well known to exhibit induced systemic resistance (ISR) to Curvularia leaf spot. We previously reported that a C6 zinc finger protein (Thc6) is responsible for a major contribution to the ISR to the leaf disease, but the types of effectors and the signals mediated by Thc6 from Trichoderma are unclear. In this work, we demonstrated that two hydrolases, Thph1 and Thph2, from T. harzianum were regulated by Thc6. Furthermore, an electrophoretic mobility shift assay (EMSA) study revealed that Thc6 regulated mRNA expression by binding to GGCTAA and GGCTAAA in the promoters of the Thph1 and Thph2 genes, respectively. Moreover, the Thph1 and Thph2 proteins triggered the transient production of reactive oxygen species (ROS) and elevated the free cytosolic calcium levels in maize leaf. Furthermore, the genes related to the jasmonate/ethylene signaling pathway were up-regulated in the wild-type maize strain. However, the ΔThph1- or ΔThph2-deletion mutants could not activate the immune defense-related genes in maize to protect against leaf disease. Therefore, we conclude that functional Thph1 and Thph2 may be required in T. harzianum to activate ISR in maize. PMID:27830829

  10. Cellulase from Trichoderma harzianum interacts with roots and triggers induced systemic resistance to foliar disease in maize.

    Science.gov (United States)

    Saravanakumar, Kandasamy; Fan, Lili; Fu, Kehe; Yu, Chuanjin; Wang, Meng; Xia, Hai; Sun, Jianan; Li, Yaqian; Chen, Jie

    2016-11-10

    Trichoderma harzianum is well known to exhibit induced systemic resistance (ISR) to Curvularia leaf spot. We previously reported that a C6 zinc finger protein (Thc6) is responsible for a major contribution to the ISR to the leaf disease, but the types of effectors and the signals mediated by Thc6 from Trichoderma are unclear. In this work, we demonstrated that two hydrolases, Thph1 and Thph2, from T. harzianum were regulated by Thc6. Furthermore, an electrophoretic mobility shift assay (EMSA) study revealed that Thc6 regulated mRNA expression by binding to GGCTAA and GGCTAAA in the promoters of the Thph1 and Thph2 genes, respectively. Moreover, the Thph1 and Thph2 proteins triggered the transient production of reactive oxygen species (ROS) and elevated the free cytosolic calcium levels in maize leaf. Furthermore, the genes related to the jasmonate/ethylene signaling pathway were up-regulated in the wild-type maize strain. However, the ΔThph1- or ΔThph2-deletion mutants could not activate the immune defense-related genes in maize to protect against leaf disease. Therefore, we conclude that functional Thph1 and Thph2 may be required in T. harzianum to activate ISR in maize.

  11. Assessment of Root Morphological Traits of 16 Tropical and Four Temperate Maize Cultivars for Nitrogen Efficiency in Short-Term Nutrient Solution Experiments with the Cigar Roll and Growth Pouch Methods

    Energy Technology Data Exchange (ETDEWEB)

    Saifu, S.; Schulte auf' m Erley, G.; Horst, W. J. [Institute for Plant Nutrition, Leibniz University of Hannover (Germany)

    2013-11-15

    Genotypic differences in N efficiency of maize have been reported by many authors. One of the reasons responsible for genotypic differences in N efficiency is differences in N uptake efficiency after anthesis. Continuous root growth and N uptake activity are responsible for the high N uptake efficiency of N-efficient genotypes. This study was conducted mainly to identify root parameters which could be used as secondary selection traits for genotypic differences in N efficiency of maize established in field experiments. The specific objective of the first experiment was to establish a relationship between root parameters with genotypic differences in N efficiency in the field, and to identify root traits to be used as secondary selection criteria for N efficiency. Four temperate and 16 tropical genotypes were grown in low-N nutrient solution with a cigar roll and a growth pouch culture for 9 and 10 days, respectively. In the cigar roll experiment individual root fractions (adventitious, seminal and primary root fractions) and in growth pouch experiment root distribution and root branching angle were of primary interest. Genotypic differences were found in most of the root traits, but the differences were not clear cut between N-efficient and inefficient genotypes with few exceptions. The N-efficient genotypes had the highest percentage of root length in the deepest (>20 cm) interval in the growth pouch, which also positively correlated with N uptake after anthesis and grain yield. The N-efficient genotypes also had a high percentage of roots in the root branching angle interval of 60-90{sup o}. It was concluded that the high N uptake efficiency of N-efficient genotypes might be related to a higher percentage of roots growing downwards (high branching angle) and a high percentage of root length in deeper soil layers enabling them to exploit nitrate in the subsoil more efficiently. These two root parameters were found promising to use as selection criteria for N

  12. 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.

  13. Comparative Analysis of Root Traits and the Associated QTLs for Maize Seedlings Grown in Paper Roll, Hydroponics and Vermiculite Culture System.

    Science.gov (United States)

    Liu, Zhigang; Gao, Kun; Shan, Shengchen; Gu, Riling; Wang, Zhangkui; Craft, Eric J; Mi, Guohua; Yuan, Lixing; Chen, Fanjun

    2017-01-01

    Root system architecture (RSA) plays an important role in the acquisition of both nitrogen (N) and phosphorus (P) from the environment. Currently RSA is rarely considered as criteria for selection to improve nutrient uptake efficiency in crop breeding. Under field conditions roots can be greatly influenced by uncontrolled environment factors. Therefore, it is necessary to develop fast selection methods for evaluating root traits of young seedlings in the lab which can then be related to high nutrient efficiency of adult plants in the field. Here, a maize recombination inbred line (RILs) population was used to compare the genetic relationship between RSA and nitrogen and phosphorous efficiency traits. The phenotypes of eight RSA-related traits were evaluated in young seedlings using three different growth systems (i.e., paper roll, hydroponics and vermiculite), and then subjected to correlation analysis with N efficiency and P efficiency related traits measured under field conditions. Quantitative trait loci (QTL) of RSA were determined and QTL co-localizations across different growth systems were further analyzed. Phenotypic associations were observed for most of RSA traits among all three culture systems. RSA-related traits in hydroponics and vermiculite weakly correlated with Nitrogen (NupE) uptake efficiency ( r = 0.17-0.31) and Phosphorus (PupE) uptake efficiency ( r = 0.22-0.34). This correlation was not found in the paper roll growth system. A total of 14 QTLs for RSA were identified in paper rolls, 18 in hydroponics, and 14 in vermiculite. Co-localization of QTLs for RSA traits were identified in six chromosome regions of bin 1.04/1.05, 1.06, 2.04/2.05, 3.04, 4.05, and 5.04/5.05. The results suggest the problem of using the phenotype from one growth system to predict those in another growth system. Assessing RSA traits at the seedling stage using either hydroponics or a vermiculite system appears better suited than the paper roll system as an important index

  14. Dynamics of organic matters in the root-rhizoplane-soil system of maize [Zea mays], 1: A simple and rapid method for measuring root respiration

    Energy Technology Data Exchange (ETDEWEB)

    Okada, K. [Tokyo Univ., Tokyo (Japan); Kumura, A.

    1990-03-15

    In the analysis of dynamics of organic matter in the root-rhizoplane-soil system, it is essential to estimate various kinds of carbon flows in the system separately. Since a simple and rapid method for measuring root respiration was needed for this purpose, the authors developed the following method. A plastic syringe is used as the chamber. Sample roots are put into a syringe, in which the air is replaced with air of known CO{sub 2} concentration and the syringe is kept at a constant temperature for a certain time. A volume of the air in the syringe is injected into the flow of N{sub 2} gas in the tube which is connected to an infrared gas analyzer. The CO{sub 2} concentration in the syringe is directly related to the reading of the analyzer. From the difference of the CO{sub 2} concentration in the syringe before and after the incubation, the respiration rate of the roots is calculated. The details of the procedure were determined by the results of experiments regarding the effects of factors concerned. (author)

  15. Effect of water deficiency on anatomical structure of codex in root hair zone of maize root tip%水分亏缺对玉米根毛区皮层解剖结构的影响

    Institute of Scientific and Technical Information of China (English)

    于涛; 李万春; 汪李宏; 岳文俊; 马旭凤; 姚雅琴; 张富仓

    2011-01-01

    【Objective】 The research was to study the effect of water deficiency on anatomical structure of codex in maize root hair zone for drought resistance mechanism.【Method】 Taking Gaonong 901 maize which has certain drought resistance in a pot experiment as four groups named control,light deficiency,moderate deficiency,severe deficiency with water treatments:75%-85% of field capacity(CK),65%-75% of field capacity(LS),55%-65% of field capacity(MS),and 45%-55% of field capacity(SS).Tissues of roots which were 10 cm distance from root tips prepared emgedded in epoxy resins were cut into half thin section for optical microscope.With green and the counterstain safranin,armour aniline blue and fluorescent dyes,the changes of cortical cell and casparian band were found through observation under Olympus BX51 microscope and calculation by image pro plus 6.0.【Result】 With increasing water deficiency,codex parenchyma cells were irregularly arranged and width of codex in root hair zone of maize seedling and jointing got thinner.Both in seedling and jointing stage,the length of endodermis in root hair zone decreased unconspicuously,and the width of endodermis changed obviously.Comparatively,the endodermis in seedling changed more obviously than that in jointing,which caused by mature casparian band enhanced mechanical strength of endodermis.Fluorescence observations showed that casparian band of axial walls of endodermis thickened on seedling stage with light deficiency.Both axial and inner tangential walls of casparian band of endodermis thickened more obviously at jointing stage with light and moderate deficiency.Endodermis which had less modified structure deformated obviously with severe deficiency.【Conclusion】 The structure of codex in root hair zone of maize at seedling was more sensitive than at jointing with water deficiency.The tolerance of roots to proper water deficit may be increased by changes such as width of codex and ligno

  16. Locally accumulated extractable compounds in mycorrhizal parts of maize roots suppress the growth of hyphae of glomus intraradices

    Czech Academy of Sciences Publication Activity Database

    Gryndler, Milan; Hršelová, Hana; Malcová, Radka; Cajthaml, Tomáš; Halada, Petr

    2003-01-01

    Roč. 38, - (2003), s. 125-138 ISSN 0015-5551 R&D Projects: GA ČR GA526/97/0595 Institutional research plan: CEZ:AV0Z6005908; CEZ:AV0Z5020903 Keywords : fractions * patassium * root extract Subject RIV: EE - Microbiology, Virology Impact factor: 1.057, year: 2003

  17. Salt-induced root protein profile changes in seedlings of maize inbred lines with differing salt tolerances

    Directory of Open Access Journals (Sweden)

    Yujing Cheng

    2014-12-01

    Full Text Available Salt stress is one of the severest growth limited-factors to agriculture production. To gain in-depth knowledge of salt-stress response mechanisms, the proteomics analysis from two maize (Zea mays L. inbred lines was carried out using two-dimensional gel electrophoresis (2-DGE and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/TOF-MS. There were 57 salt-regulated proteins identified, 21 and 36 proteins were differentially regulated in inbred lines 'Nongda 1145' (salt-resistant and 'D340' (salt-sensitive, respectively. The identified proteins were distributed in 11 biological processes and seven molecular functions. Under salt stress, proteins related to antioxidation and lignin synthesis were increased in both inbred lines. The relative abundance of proteins involved in translation initiation, elongation, and protein proteolysis increased in 'Nongda 1145' and decreased in 'D340'. In addition, the abundance of proteins involved in carbohydrate metabolism, protein refolding, ATP synthase and transcription differed between the two inbred lines. Our results suggest that the enhanced ability of salt-tolerant inbred line 'Nongda 1145' to combat salt stress occurs via regulation of transcription factors promoting increased antioxidation and lignin biosynthesis, enhanced energy production, and acceleration of protein translation and protein proteolysis.

  18. Automorphosis-like growth in etiolated pea seedlings is induced by the application of chemicals affecting perception of gravistimulation and its signal transduction

    Science.gov (United States)

    Miyamoto, Kensuke; Hoshino, Tomoki; Hitotsubashi, Reiko; Yamashita, Masamichi; Ueda, Junichi

    Both microgravity conditions in space and simulated microgravity using a 3-dimensional clinostat resulted in: (1) automorphosis of etiolated pea seedlings, (2) epicotyls bending ca. 45° from the vertical line to the direction away from cotyledons, (3) inhibition of hook formation and (4) alternation of growth direction of roots. These facts indicate that the growth and development of etiolated pea seedlings on earth is under the influence of gravistimulation. Lanthanum and gadolinium ions, blockers of stretch-activated mechanosensitive ion channels, induced automorphosis-like epicotyl bending. Cantharidin, an inhibitor of protein phosphatase, also phenocopied automorphosis-like growth. On the other hand, cytochalasin B, cytochalasin D and brefeldin A did not induce automorphological epicotyl bending and inhibition of hook formation, although these compounds strikingly inhibited elongation of etiolated pea epicotyls. These results strongly suggest that stretch-activated mechanosensitive ion channels are involved in the perception of signals of gravistimuli in plants, and they are transduced by protein phosphorylation and dephosphorylation cascades by changing levels of calcium ions. Possible mechanisms to induce automorphosis-like growth in relation to gravity signals in etiolated pea seedlings are discussed.

  19. Chemical ionization mass spectrometry of indol-3yl-acetic acid and cis-abscisic acid: evaluation of negative ion detection and quantification of cis-abscisic acid in growing maize roots

    International Nuclear Information System (INIS)

    Rivier, L.; Saugy, M.

    1986-01-01

    Mass spectra of the derivatives of indol-3yl-acetic acid and cis-abscisic acid were obtained in electron impact and chemical ionization positive ion and negative ion modes. The respective merits of methane, isobutane, and ammonia as reagent gases for structure determination and sensitive detection were compared using the methyl esters. From one to 10 fluorine atoms were attached to IAA to improve the electron-capturing properties of the molecule. The best qualitative information was obtained when using positive ion chemical ionization with methane. However, the most sensitive detection, with at least two ions per molecule, was achieved by electron impact on the IAA-HFB-ME derivative and by negative ion chemical ionization with NH 3 on the ABA-methyl ester derivative. p ]Quantitative analyses of ABA in different parts of maize (Zea mays cv. LG 11) root tips were performed by the latter technique. It was found that the cap and apex contained less ABA than the physiologically older parts of the root such as the elongation zone and the more differentiated tissues. This technique was also used to show a relation between maize root growth and the endogenous ABA level of the elongation zone and root tip: there is more ABA in the slowly growing roots than in the rapidly growing ones. (author)

  20. Gibberellins and gravitropism in maize shoots: endogenous gibberellin-like substances and movement and metabolism of [3]gibberellin A

    International Nuclear Information System (INIS)

    Rood, S.B.; Kaufman, P.B.; Abe, H.; Pharis, R.P.

    1987-01-01

    [ 3 H]Gibberellin A 20 (GA 20 ) of high specific radioactivity was applied equilaterally in a ring of microdrops to the internodal pulvinus of shoots of 3-week-old vertical normal maize (Zea mays L.), and to a pleiogravitropic (prostrate) maize mutant, lazy (la). All plants converted the [ 3 H]GA 1 - and [ 3 H]GA 29 -like metabolites as well as to several metabolites with the partitioning and chromatographic behavior of glucosyl conjugates of [ 3 H]GA 1 [ 3 H]GA 29 , and [ 3 H]GA 8 . The tentative identification of these putative [ 3 H]GA glucosyl conjugates was further supported by the release of the free [ 3 H]GA moiety after cleavage with cellulase. Within 12 hours of the [ 3 H]GA 20 feed, there was a significantly higher proportion of total radioactivity in lower than in upper halves of internode and leaf sheaf pulvini in gravistimulated normal maize. Further, there was a significantly higher proportion of putative free GA metabolites of [ 3 H]GA 20 , especially [ 3 H] GA 1 , in the lower halves of normal maize relative to upper halves. The differential localization of the metabolites between upper and lower halves was not apparent in the pleiogravitropic mutant, la. Endogenous GA-like substances were also examined in gravistimulated maize shoots. Forty-eight hours after gravistimulation of 3-week-old maize seedlings, endogenous free GA-like substances in upper and lower leaf sheath and internode pulvini halves were extracted, chromatographed, and bioassayed using the Tanginbozu dwarf rice microdroassay. Lower halves contained higher total levels of GA-like activity

  1. Atividade do sistema antioxidante e desenvolvimento de aerênquima em raízes de milho 'Saracura' Antioxidant system activity and aerenchyma formation in 'Saracura' maize roots

    Directory of Open Access Journals (Sweden)

    Fabricio José Pereira

    2010-05-01

    Full Text Available Este trabalho teve como objetivo avaliar a influência de sucessivos ciclos de seleção do milho 'Saracura' na atividade das enzimas do sistema antioxidante, e a relação dessas enzimas com a capacidade dessa variedade em desenvolver aerênquima. Sementes de 18 ciclos de seleção intercalados do milho 'Saracura' e da cultivar BR 107, sensível à hipoxia, foram semeadas em vasos e em casa de vegetação. As plantas foram submetidas ao alagamento intermitente de dois em dois dias. As amostras de raízes foram coletadas após 60 dias e analisaram-se as atividades das enzimas peroxidase do guaiacol, peroxidase do ascorbato e catalase, além da capacidade das plantas de cada ciclo desenvolverem aerênquima. Ao longo dos ciclos, as plantas apresentaram modificações na atividade das enzimas, com aumento na de peroxidase do ascorbato e diminuição na de catalase e de peroxidase do guaiacol. Observou-se, ainda, maior capacidade de desenvolver aerênquima nos últimos ciclos de seleção. A redução na atividade das enzimas do sistema antioxidante parece estar relacionada a um desbalanço na decomposição de H2O2.This work aimed to assess the influence of successive selection cycles in 'Saracura' maize on the enzyme activity of the antioxidant system and the relationship of these enzymes with the aerenchyma development capacity of this variety. Seeds of 18 intercalated selection cycles of the 'Saracura' maize and of the cultivar BR 107, sensitive to hipoxia, were sown in pots in the greenhouse. Plants were submitted to intermittent soil flooding each two days. After 60 days, the roots were sampled and analysis were done for the guaiacol peroxidase, ascorbate peroxidase, and catalase activities and for the capacity of the plants of each cycle to develop aerenchyma. The plants showed modifications in enzyme activity along the cycles, increasing the ascorbate peroxidase activity and decreasing the catalase and guaiacol peroxidase ones. A greater

  2. Intercropping Maize With Legumes for Sustainable Highland Maize Production

    Directory of Open Access Journals (Sweden)

    Adirek Punyalue

    2018-02-01

    Full Text Available Residue burning to prepare soil for maize growing deprives the soil of both protective cover and organic matter, and it exacerbates environmental issues such as Southeast Asia's haze problem. This paper reports on a study that evaluated the effectiveness of maize/legume intercropping as an alternative to maize cultivation with residue burning. Cowpea (Vigna unguiculata, mung bean (V. radiata, rice bean (V. umbellata, and lablab (Lablab purpureus were sown into a standing maize crop 30 days before harvest, and the results were compared with a maize crop grown using residue burning as the method for land preparation at Pang Da Agricultural Station in Chiang Mai, Thailand, in a replicated trial conducted over 3 growing seasons from 2012 to 2014. Intercropping increased maize grain yield by 31–53% and left 70–170% more residue containing 113–230% more nitrogen than the maize sown after residue burning, depending on the legume, and decreased weed dry weight by two-thirds after 2 seasons. Soil biodiversity was enriched by the intercrops, with a doubling in the spore density of arbuscular mycorrhizal fungi in the root-zone soil and increased abundance, diversity (Shannon index, and richness of the soil macrofauna. The abundance of soil animals increased with crop residue dry weight (r = 0.90, P < 0.05 and nitrogen content (r = 0.98, P < 0.01. The effect of intercropping on maize grain yield and accumulation of residue and nitrogen were then confirmed in a participatory experiment involving farmers in 2 highland villages in the Phrao and Chiang Dao districts of Chiang Mai Province with maize and rice bean in 2015. The effects of maize/legume intercropping—increased nitrogen accumulation and crop residue, enhanced soil biodiversity, suppression of weeds, and protection of the soil surface, which enabled the maize to be sown without land clearing with fire—should all contribute to sustainable highland maize production.

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

    Science.gov (United States)

    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.

  4. Colonization and community structure of arbuscular mycorrhizal fungi in maize roots at different depths in the soil profile respond differently to phosphorus inputs on a long-term experimental site.

    Science.gov (United States)

    Wang, Chao; White, Philip J; Li, Chunjian

    2017-05-01

    Effects of soil depth and plant growth stages on arbuscular mycorrhizal fungal (AMF) colonization and community structure in maize roots and their potential contribution to host plant phosphorus (P) nutrition under different P-fertilizer inputs were studied. Research was conducted on a long-term field experiment over 3 years. AMF colonization was assessed by AM colonization rate and arbuscule abundances and their potential contribution to host P nutrition by intensity of fungal alkaline phosphatase (ALP)/acid phosphatase (ACP) activities and expressions of ZmPht1;6 and ZmCCD8a in roots from the topsoil and subsoil layer at different growth stages. AMF community structure was determined by specific amplification of 18S rDNA. Increasing P inputs up to 75-100 kg ha -1  yr -1 increased shoot biomass and P content but decreased AMF colonization and interactions between AMF and roots. AM colonization rate, intensity of fungal ACP/ALP activities, and expression of ZmPht1;6 in roots from the subsoil were greater than those from topsoil at elongation and silking but not at the dough stage when plants received adequate or excessive P inputs. Neither P input nor soil depth influenced the number of AMF operational taxonomic units (OTUs) present in roots, but P-fertilizer input, in particular, influenced community composition and relative AMF abundance. In conclusion, although increasing P inputs reduce AMF colonization and influence AMF community structure, AMF can potentially contribute to plant P nutrition even in well-fertilized soils, depending on the soil layer in which roots are located and the growth stage of host plants.

  5. 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

    [3H]Gibberellin A20 (GA20) of high specific radioactivity (49.9 gigabecquerel per millimole) was applied equilaterally in a ring of microdrops to the internodal pulvinus of shoots of 3-week-old gravistimulated and vertical normal maize (Zea mays L.), and to a pleiogravitropic (prostrate) maize mutant, lazy (la). All plants converted the [3H]GA20 to [3H]GA1- and [3H]GA29-like metabolites as well as to several metabolites with the partitioning and chromatographic behavior of glucosyl conjugates of [3H]GA1, [3H]GA29, and [3H]GA8. The tentative identification of these putative [3H]GA glucosyl conjugates was further supported by the release of the free [3H]GA moiety after cleavage with cellulase. Within 12 hours of the [3H]GA20 feed, there was a significantly higher proportion of total radioactivity in lower than in upper halves of internode and leaf sheath pulvini in gravistimulated normal maize. Further, there was a significantly higher proportion of putative free GA metabolites of [3H]GA20, especially [3H]GA1, in the lower halves of normal maize relative to upper halves. The differential localization of the metabolites between upper and lower halves was not apparent in the pleiogravitropic mutant, la. Endogenous GA-like substances were also examined in gravistimulated maize shoots. Forty-eight hours after gravistimulation of 3-week-old maize seedlings, endogenous free GA-like substances in upper and lower leaf sheath and internode pulvini halves were extracted, chromatographed, and bioassayed using the "Tanginbozu" dwarf rice microdrop assay. Lower halves contained consistently higher total levels of GA-like activity. The qualitative elution profile of GA-like substances differed consistently, upper halves containing principally a GA20-like substance and lower halves containing principally a GA20-like substance and lower halves containing mainly GA1-like and GA19-like substances. Gibberellins A1 (10 nanograms per gram) and A20 (5 nanograms per gram) were identified

  6. Evolução da anatomia radicular do milho 'Saracura' em ciclos de seleção sucessivos Evolution of the root anatomy of 'Saracura' maize in successive selection cycles

    Directory of Open Access Journals (Sweden)

    Fabricio José Pereira

    2008-12-01

    Full Text Available Este trabalho teve como objetivo verificar as modificações nas características anatômicas radiculares relacionadas à hipoxia, durante 18 ciclos de seleção da variedade de milho (Zea mays BRS 4154 Saracura, adaptada a áreas sujeitas a alagamento. A variedade BR 107 e o híbrido simples BRS 1010, suscetíveis ao alagamento, foram utilizados como controle. As diferentes cultivares foram submetidas a alagamentos intermitentes, a cada dois dias, durante dois meses. As amostras radiculares foram preparadas e analisadas em microscopiaóptica. Em relação ao grupo controle e aos ciclos anteriores de seleção, a BRS 4154 teve aumento na formação de aerênquima, diminuição do córtex, diminuição do diâmetro dos vasos, diminuição da camada subepidérmica, aumento na espessura do floema e epiderme. Os sucessivos ciclos de seleção melhoraram as características do milho 'Saracura' e sua tolerância a ambientes alagados.This work aimed to verify the modifications in the root anatomical characteristics related to hypoxia, along 18 selection cycles of the maize (Zea mays cultivar BRS 4154 Saracura, adapted to areas subject to flooding. Cultivars not tolerant to fooding, BR 107 and the simple hybrid BRS 1010, were used as controls. The different cultivars were subjected to intermittent soil waterlogging every two days for two months. The root samples were prepared and analyzed through light microscopy. Compared to the controls group and to early selection cycles, BRS 4154 had increased development of aerenchyma, decreased cortex thickness, decreased metaxylem diameter, decreased subepidermal layer, and increased epidermis and phloem thickness. The successive selection cycles improved 'Saracura' maize characteristics and its tolerance to flooding environments.

  7. Phosphorus acquisition efficiency in arbuscular mycorrhizal maize is correlated with the abundance of root-external hyphae and the accumulation of transcripts encoding PHT1 phosphate transporters

    DEFF Research Database (Denmark)

    Sawers, Ruairidh J H; Svane, Simon F; Quan, Clement

    2016-01-01

    content, abundance of intra-radical and root-external fungal structures, mycorrhizal phosphorus uptake, and accumulation of transcripts encoding plant PHT1 family phosphate transporters varied among lines. Larger growth responses in Oh43 were correlated with extensive development of root-external hyphae...

  8. Zealactones. Novel natural strigolactones from maize

    NARCIS (Netherlands)

    Charnikhova, Tatsiana V.; Gaus, Katharina; Lumbroso, Alexandre; Sanders, Mark; Vincken, Jean Paul; Mesmaeker, de Alain; Ruyter-Spira, Carolien P.; Screpanti, Claudio; Bouwmeester, Harro J.

    2017-01-01

    In the root exudate and root extracts of maize hybrid cv NK Falkone seven putative strigolactones were detected using UPLC-TQ-MS-MS. All seven compounds displayed MS-MS-fragmentation common for strigolactones and particularly the presence of a fragment of m/z 97 Da, which may indicate the

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

    Science.gov (United States)

    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.

  10. Host Status of Five Weed Species and Their Effects on Pratylenchus zeae Infestation of Maize.

    Science.gov (United States)

    Jordaan, E M; De Waele, D

    1988-10-01

    The host suitability of five of the most common weed species occurring in maize (Zea mays L.) fields in South Africa to Pratylenchus zeae was tested. Based on the number of nematodes per root unit, mealie crotalaria (Crotalaria sphaerocarpa) was a good host; goose grass (Eleusine indica), common pigweed (Amaranthus hybridus), and thorn apple (Datura stramonium) were moderate hosts; and khaki weed (Tagetes minuta) was a poor host. Only the root residues of khaki weed suppressed the P. zeae infestation of subsequently grown maize. When goose grass, khaki weed, and mealie crotalaria were grown in association with maize in soil infested with P. zeae, goose grass and khaki weed severely suppressed maize root development; this resulted in a low number of nematodes per maize root system and a high number of nematodes per maize root unit. Mealie crotalaria did not restrict maize root growth and did not affect nematode densities per maize root system or maize root unit. Special attention should be given to the control of mealie crotalaria, which is a good host for P. zeae, and goose grass, which, in addition to its ability to compete with maize, is also a suitable host for P. zeae.

  11. Romanian maize

    DEFF Research Database (Denmark)

    Sauer, Johannes; Balint, Borbala

    This research aims at shedding empirical light on the relative efficiency of small-scale maize producers in Romania. Farmers in transition countries still face heavily distorted price systems resulting from imperfect market conditions and socioeconomic and institutional constraints. To capture...

  12. Phosphorus acquisition efficiency in arbuscular mycorrhizal maize is correlated with the abundance of root-external hyphae and the accumulation of transcripts encoding PHT1 phosphate transporters

    DEFF Research Database (Denmark)

    Sawers, Ruairidh J. H.; Svane, Simon; Quan, Clement

    2017-01-01

    -internal and -external fungal structures, mycorrhizal phosphorus uptake, and accumulation of transcripts encoding plant PHT1 family phosphate transporters varied among lines. Superior response in Oh43 is correlated with extensive development of root-external hyphae, accumulation of specific Pht1 transcripts and high...

  13. Aberrant cell divisions in root meristeme of maize following exposure to X-rays low doses compared to similar effects of 50 Hz electromagnetic exposure

    Directory of Open Access Journals (Sweden)

    Luchian T.

    2012-04-01

    Full Text Available The response of maize to radiation exposure was investigated by two cytogenetic methods considering the importance of the geno-toxic effect for environmental and agricultural purposes. Uniform genophond seeds, freshly germinated, were exposed to relatively low radiation doses using a radiotherapy X-ray applicator from a hospital irradiation device and to a 50 Hz electromagnetic field with about 10 mT magnetic induction (generated within laboratory assembled electromagnetic coils. Radicular meristeme tissue aliquots were prevailed for cytogenetic investigation based on microscopic observations and cell counting. Microscope slides were prepared following a specific procedure (squash technique and Feulgen method based on modified Carr reactive coloration. Mitotic index as well as chromosomal aberration percentage were calculated for more than 30,000 cells taken into account. From a qualitative viewpoint, chromosomal aberrations such as interchromatidian bridges, lagging and expelled chromosomes and multipolar divisions were evidenced - no distinct situation for either ionizing radiation or electromagnetic field being identified. The main quantitative difference consisted in the increased mitotic index for electromagnetic exposure increased times compared with the diminished mitotic index in the case of low X-ray doses.

  14. Amyloplast Distribution Directs a Root Gravitropic Reaction

    Science.gov (United States)

    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

  15. Gravistimulation changes expression of genes encoding putative carrier proteins of auxin polar transport in etiolated pea epicotyls

    Science.gov (United States)

    Hoshino, T.; Hitotsubashi, R.; Miyamoto, K.; Tanimoto, E.; Ueda, J.

    STS-95 space experiment has showed that auxin polar transport in etiolated epicotyls of pea (Pisum sativum L. cv. Alaska) seedlings is controlled by gravistimulation. In Arabidopsis thaliana auxin polar transport has considered to be regulated by efflux and influx carrier proteins in plasma membranes, AtPIN1 and AtAUX1, respectively. In order to know how gravistimuli control auxin polar transport in etiolated pea epicotyls at molecular levels, strenuous efforts have been made, resulting in successful isolation of full-length cDNAs of a putative auxin efflux and influx carriers, PsPIN2 and PsAUX1, respectively. Significantly high levels in homology were found on nucleotide and deduced amino acid sequences among PsPIN2, PsPIN1 (accession no. AY222857, Chawla and DeMason, 2003) and AtPINs, and also among PsAUX1, AtAUX1 and their related genes. Phylogenetic analyses based on the deduced amino acid sequences revealed that PsPIN2 belonged to a subclade including AtPIN3, AtPIN4 relating to lateral transport of auxin, while PsPIN1 belonged to the same clade as AtPIN1 relating to auxin polar transport. In the present study, we examined the effects of gravistimuli on the expression of PsPINs and PsAUX1 in etiolated pea seedlings by northern blot analysis. Expression of PsPIN1, PsPIN2 and PsAUX1 in hook region of 3.5-d-old etiolated pea seedlings grown under simulated microgravity conditions on a 3-D clinostat increased as compared with that of the seedlings grown under 1 g conditions. On the other hand, that of PsPIN1 and PsAUX1 in the 1st internode region under simulated microgravity conditions on a 3-D clinostat also increased, while that of PsPIN2 was affected little. These results suggest that expression of PsPIN1, PsPIN2 and PsAUX1 regulating polar/lateral transport of auxin is substantially under the control of gravity. A possible role of PsPINs and PsAUX1 of auxin polar transport in etiolated pea seedlings will also be discussed.

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

    Directory of Open Access Journals (Sweden)

    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.

  17. 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.

  18. Water transfer in an alfalfa/maize association

    International Nuclear Information System (INIS)

    Corak, S.J.; Blevins, D.G.; Pallardy, S.G.

    1987-01-01

    The authors investigated the possibility of interspecific water transfer in an alfalfa (Medicago sativa L.) and maize (Zea mays L.) association. An alfalfa plant was grown through two vertically stacked plastic tubes. A 5 centimeter air gap between tubes was bridged by alfalfa roots. Five-week old maize plants with roots confined to the top tube were not watered, while associated alfalfa roots had free access to water in the bottom tube (the -/+ treatment). Additional treatments included: top and bottom tubes watered (+/+), top and bottom tubes droughted (-/-), and top tube droughted after removal of alfalfa root bridges and routine removal of alfalfa tillers (-*). Predawn leaf water potential of maize in the -/+ treatment fell to -1.5 megapascals 13 days after the start of drought; thereafter, predawn and midday potentials were maintained near -1.9 megapascals. Leaf water potentials of maize in the -/- and -* treatments declined steadily; all plants in these treatments were completely desiccated before day 50. High levels of tritium activity were detected in water extracted from both alfalfa and maize leaves after 3 H 2 O was injected into the bottom -/+ tube at day 70 or later. Maize in the -/+ treatment was able to survive an otherwise lethal period of drought by utilizing water lost by alfalfa roots

  19. Harnessing maize biodiversity

    Science.gov (United States)

    Maize is a remarkably diverse species, adapted to a wide range of climatic conditions and farming practices. The latitudinal range of maize is immense, ranging from 54°N in Alberta, Canada, to 45°S in the province of Chubut, Argentina. In terms of altitude, maize is cultivated from sea level to 4000...

  20. The effect of root temperature on the uptake and metabolism of anions by the root system of Zea mays L. I

    International Nuclear Information System (INIS)

    Holobrada, M.; Mistrik, I.; Kolek, J.

    1980-01-01

    The effect of root temperature upon the uptake of 35 S-sulfate by intact 21 days old maize roots was discussed. The plant roots grown at 20 degC were cooled in steps down to 15 degC or 5 degC. The rate of 35 S uptake was studied both in the whole root system and separately in the individual roots (primary seminal root, seminal adventitious roots and nodal roots). Differences were ascertained at lower uptakes by various root samples from resistant and nonresistant maize cultivars. (author)

  1. Aflatoxins and fumonisin contamination of marketed maize, maize ...

    African Journals Online (AJOL)

    Aflatoxins and fumonisin contamination of marketed maize, maize bran and maize used as animal feed in northern ... PROMOTING ACCESS TO AFRICAN RESEARCH ... African Journal of Food, Agriculture, Nutrition and Development.

  2. Influence of planting methods on root development, crop productivity and water use efficiency in maize hybrids Influencia de métodos de siembra sobre el desarrollo radical, productividad y eficiencia del uso del agua en híbridos de maíz

    Directory of Open Access Journals (Sweden)

    Muhammad B. Khan

    2012-12-01

    Full Text Available Optimum planting methods better ensure water and nutrient supply through improved root development resulting in better crop growth and productivity. This study was conducted to evaluate the effects of planting methods on root development, crop allometry, water use efficiency (WUE, productivity and economic returns of different maize (Zea mays L. hybrids. Maize hybrids NK-6621, Pioneer-30Y87, and Pioneer-30Y58 were sown on beds, ridges, and flat surface. Ridge sowing was better followed by bed sowing; while amongst the hybrids, 'Pioneer-30Y87' performed the best. Well-developed root system, with longer primary root, more number of lateral roots and higher root growth rate, was observed in 'Pioneer-30Y87' planted on ridges, which led to higher WUE, grain yield and its related traits. The same hybrid exhibited higher leaf area index and crop growth rate, and maximum net return and benefit:cost ratio sowed on ridges. Overall, the ridge sowing improved root development resulting in better allometry, productivity (5.45 t ha-1, and WUE (1.345 kg m-3, in all the maize hybrids. Although maize hybrids exhibited different response to different planting methods; maximum grain yield (5.63 t ha-1, WUE (1.41 kg m-3, and net economic returns were observed from hybrid Pioneer-30Y87.Métodos óptimos de siembra aseguran mejor suministro de agua y nutrientes a través del mejorado desarrollo de raíces que resulta en mejor crecimiento y productividad de los cultivos. Este estudio se realizó para evaluar los efectos de los métodos de siembra en el desarrollo de las raíces, alometría de cultivos, uso eficiente del agua (WUE, productividad y rentabilidad económica de diferentes híbridos de maíz (Zea mays L.. Híbridos de maíz NK-6621, Pioneer 30Y87, y 30Y58-Pioneer se sembraron en camas, surcos, y superficie plana. La siembra en surco fue mejor, seguida por siembra en cama, mientras entre los híbridos, 'Pioneer 30Y87' tuvo los mejores resultados. Se observ

  3. THE IMPORTANCE OF WESTERN CORN ROOTWORM IN CONTINUOUS MAIZE

    Directory of Open Access Journals (Sweden)

    Marija Ivezić

    2006-06-01

    Full Text Available Western Corn Rootworm (Diabrotica virgifera virgifera LeConte is considered to be one of the most important and potentially most severe pest of maize worldwide. The pest was detected in Croatia for the first time in 1995. Since then it has been spread over all areas with maize production in Croatia. The economically most efficient and preventive control measure is crop rotation and growing maize hybrids that show tolerance to WCR. The trials were settled in the area near Dubosevica where in 2002 and 2003 the economic damages caused by WCR were up to 80%. The aim of this investigation is to determine damages on maize root caused by WCR and loss in grain yield on commercial maize hybrids in continuous farming. Pheromone traps, type Csal♀m♂N®, were used in order to monitor WCR population dynamics. In the period of two months, 366 WCR adult beetles in total were captured. Root damage was evaluated according to Iowa Node Injury Scale and grain yield was measured and corrected to 14% moisture. Furthermore, the plant lodging, as a consequence of larval feeding, was assessed. The results have shown that root damage for hybrid Bc 5982 was 1.15, and 0.73 damage was on Pr 35p 12 roots. The grain yield obtained from hybrid Bc 5982 was 11.7 t/ha, and Pr 35p 12 had 12.3 t/ha. Statistical analyses showed that there were no significant differences in root damage and losses in grain yield between the two investigated hybrids. Results of this investigation indicate that growing maize for 2 to 3 years in continuous farming, in the same field, would not cause economically significant loss in maize gain yield.

  4. Response of soil carbon fractions and dryland maize yield to mulching

    Science.gov (United States)

    Stimulation of root growth from mulching may enhance soil C fractions under maize (Zea mays L.). We studied the 5-yr straw (SM) and plastic film (PM) mulching effect on soil C fractions and maize yield compared with no mulching (CK) in the Loess Plateau of China. Soil samples collected from 0- to 10...

  5. Chemical and nutritional values of maize and maize products ...

    African Journals Online (AJOL)

    Maize and maize products in selected grain markets within Kaduna, Nigeria, were obtained and investigated for proximate and mineral composition analysis using Atomic Absorption Spectrophotometer (AAS) and flame photometer. Proximate composition of maize and maize products were in the range of 11.6- 20 .0% ...

  6. Resistance of maize varieties to the maize weevil Sitophilus zeamais

    African Journals Online (AJOL)

    This study aimed at evaluating commonly used maize varieties, collected from Melkasa and Bako Agricultural Research Centers and Haramaya University, Ethiopia, against the maize weevil Sitophilus zeamais Motsch., one of the most important cosmopolitan stored product pests in maize. A total of 13 improved maize ...

  7. Uptake, translocation, and debromination of polybrominated diphenyl ethers in maize

    Institute of Scientific and Technical Information of China (English)

    Moming Zhao; Shuzhen Zhang; Sen Wang; Honglin Huang

    2012-01-01

    Uptake,translocation and debromination of three polybrominated diphenyl ethers(PBDEs),BDE-28,-47 and-99,in maize were studied in a hydroponic experiment.Roots took up most of the PBDEs in the culture solutions and more highly brominated PBDEs had a stronger uptake capability.PBDEs were detected in the stems and leaves of maize after exposure but rarely detected in the blank control plants.Furthermore,PBDE concentrations decreased from roots to stems and then to leaves,and a very clear decreasing gradient was found in segments upwards along the stem.These altogether provide substantiating evidence for the acropetal translocation of PBDEs in maize.More highly brominated PBDEs were translocated with more difficulty.Radial translocation of PBDEs from nodes to sheath inside maize was also observed.Both acropetal and radial translocations were enhanced at higher transpiration rates,suggesting that PBDE transport was probably driven by the transpiration stream.Debromination of PBDEs occurred in all parts of the maize,and debromination patterns of different parent PBDEs and in different parts of a plant were similar but with some differences.This study for the first time provides direct evidence for the acropetal translocation of PBDEs within plants,elucidates the process of PBDE transport and clarifies the debromination products of PBDEs in maize.

  8. Effect of root temperature on the uptake and metabolism of anions by the root system of Zea mays L. I. Uptake of sulphate by resistant and non-resistant plants

    Energy Technology Data Exchange (ETDEWEB)

    Holobrada, M; Mistrik, I; Kolek, J [Institute of Experimental Biology and Ecology of the Slovak Academy of Sciences, Bratislava (Czechoslovakia)

    1980-01-01

    The effect of root temperature upon the uptake of /sup 35/S-sulfate by intact 21 days old maize roots was discussed. The plant roots grown at 20 degC were cooled in steps down to 15 degC or 5 degC. The rate of /sup 35/S uptake was studied both in the whole root system and separately in the individual roots (primary seminal root, seminal adventitious roots and nodal roots). Differences were ascertained at lower uptakes by various root samples from resistant and nonresistant maize cultivars.

  9. Differences in U root-to-shoot translocation between plant species explained by U distribution in roots

    Energy Technology Data Exchange (ETDEWEB)

    Straczek, Anne; Duquene, Lise [Belgium Nuclear Research Centre (SCK.CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol (Belgium); Wegrzynek, Dariusz [IAEA, Seibersdorf Laboratories, A-2444 Seibersdorf (Austria); Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow (Poland); Chinea-Cano, Ernesto [IAEA, Seibersdorf Laboratories, A-2444 Seibersdorf (Austria); Wannijn, Jean [Belgium Nuclear Research Centre (SCK.CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol (Belgium); Navez, Jacques [Royal Museum of Africa, Department of Geology, Leuvensesteenweg 13, 3080 Tervuren (Belgium); Vandenhove, Hildegarde, E-mail: hvandenh@sckcen.b [Belgium Nuclear Research Centre (SCK.CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol (Belgium)

    2010-03-15

    Accumulation and distribution of uranium in roots and shoots of four plants species differing in their cation exchange capacity of roots (CECR) was investigated. After exposure in hydroponics for seven days to 100 mumol U L{sup -1}, distribution of uranium in roots was investigated through chemical extraction of roots. Higher U concentrations were measured in roots of dicots which showed a higher CECR than monocot species. Chemical extractions indicated that uranium is mostly located in the apoplasm of roots of monocots but that it is predominantly located in the symplasm of roots of dicots. Translocation of U to shoot was not significantly affected by the CECR or distribution of U between symplasm and apoplasm. Distribution of uranium in roots was investigated through chemical extraction of roots for all species. Additionally, longitudinal and radial distribution of U in roots of maize and Indian mustard, respectively showing the lowest and the highest translocation, was studied following X-ray fluorescence (XRF) analysis of specific root sections. Chemical analysis and XRF analysis of roots of maize and Indian mustard clearly indicated a higher longitudinal and radial transport of uranium in roots of Indian mustard than in roots of maize, where uranium mostly accumulated in root tips. These results showed that even if CECR could partly explain U accumulation in roots, other mechanisms like radial and longitudinal transport are implied in the translocation of U to the shoot.

  10. Differences in U root-to-shoot translocation between plant species explained by U distribution in roots

    International Nuclear Information System (INIS)

    Straczek, Anne; Duquene, Lise; Wegrzynek, Dariusz; Chinea-Cano, Ernesto; Wannijn, Jean; Navez, Jacques; Vandenhove, Hildegarde

    2010-01-01

    Accumulation and distribution of uranium in roots and shoots of four plants species differing in their cation exchange capacity of roots (CECR) was investigated. After exposure in hydroponics for seven days to 100 μmol U L -1 , distribution of uranium in roots was investigated through chemical extraction of roots. Higher U concentrations were measured in roots of dicots which showed a higher CECR than monocot species. Chemical extractions indicated that uranium is mostly located in the apoplasm of roots of monocots but that it is predominantly located in the symplasm of roots of dicots. Translocation of U to shoot was not significantly affected by the CECR or distribution of U between symplasm and apoplasm. Distribution of uranium in roots was investigated through chemical extraction of roots for all species. Additionally, longitudinal and radial distribution of U in roots of maize and Indian mustard, respectively showing the lowest and the highest translocation, was studied following X-ray fluorescence (XRF) analysis of specific root sections. Chemical analysis and XRF analysis of roots of maize and Indian mustard clearly indicated a higher longitudinal and radial transport of uranium in roots of Indian mustard than in roots of maize, where uranium mostly accumulated in root tips. These results showed that even if CECR could partly explain U accumulation in roots, other mechanisms like radial and longitudinal transport are implied in the translocation of U to the shoot.

  11. Improved tolerance of maize (Zea mays L.) to heavy metals by colonization of a dark septate endophyte (DSE) Exophiala pisciphila

    International Nuclear Information System (INIS)

    Li, T.; Liu, M.J.; Zhang, X.T.; Zhang, H.B.; Sha, T.; Zhao, Z.W.

    2011-01-01

    Dark septate endophytes (DSE) are ubiquitous and abundant in stressful environments including heavy metal (HM) stress. However, our knowledge about the roles of DSE in improving HM tolerance of their host plants is poor. In this study, maize (Zea mays L.) was inoculated with a HM tolerant DSE strain Exophiala pisciphila H93 in lead (Pb), zinc (Zn), and cadmium (Cd) contaminated soils. E. pisciphila H93 successfully colonized and formed typical DSE structures in the inoculated maize roots. Colonization of E. pisciphila H93 alleviated the deleterious effects of excessive HM supplements and promoted the growth of maize (roots and shoots) under HM stress conditions, though it significantly decreased the biomass of inoculated maize under no HM stress. Further analysis showed that the colonization of E. pisciphila H93 improved the tolerance of maize to HM by restricting the translocation of HM ions from roots to shoots. This study demonstrated that under higher HM stress, such a mutual symbiosis between E. pisciphila and its host (maize) may be an efficient strategy to survive in the stressful environments. - Research Highlights: →Effect of DSE (E. pisciphila) on heavy metal tolerance of maize host was studied. →DSE alleviated the deleterious effect of excessive heavy metals on maize. →DSE restricted the transfer of heavy metals from the roots to shoots in maize. →DSE colonization improved the tolerance of their host plants to heavy metals.

  12. Improved tolerance of maize (Zea mays L.) to heavy metals by colonization of a dark septate endophyte (DSE) Exophiala pisciphila

    Energy Technology Data Exchange (ETDEWEB)

    Li, T.; Liu, M.J.; Zhang, X.T. [Key Laboratory of Conservation and Utilization for Bioresources, Yunnan University, Kunming, 650091 Yunnan (China); Zhang, H.B. [Key Laboratory of Conservation and Utilization for Bioresources, Yunnan University, Kunming, 650091 Yunnan (China); Department of Biology, Yunnan University, Kunming, 650091 Yunnan (China); Sha, T. [Key Laboratory of Conservation and Utilization for Bioresources, Yunnan University, Kunming, 650091 Yunnan (China); Zhao, Z.W., E-mail: zhaozhw@ynu.edu.cn [Key Laboratory of Conservation and Utilization for Bioresources, Yunnan University, Kunming, 650091 Yunnan (China)

    2011-02-15

    Dark septate endophytes (DSE) are ubiquitous and abundant in stressful environments including heavy metal (HM) stress. However, our knowledge about the roles of DSE in improving HM tolerance of their host plants is poor. In this study, maize (Zea mays L.) was inoculated with a HM tolerant DSE strain Exophiala pisciphila H93 in lead (Pb), zinc (Zn), and cadmium (Cd) contaminated soils. E. pisciphila H93 successfully colonized and formed typical DSE structures in the inoculated maize roots. Colonization of E. pisciphila H93 alleviated the deleterious effects of excessive HM supplements and promoted the growth of maize (roots and shoots) under HM stress conditions, though it significantly decreased the biomass of inoculated maize under no HM stress. Further analysis showed that the colonization of E. pisciphila H93 improved the tolerance of maize to HM by restricting the translocation of HM ions from roots to shoots. This study demonstrated that under higher HM stress, such a mutual symbiosis between E. pisciphila and its host (maize) may be an efficient strategy to survive in the stressful environments. - Research Highlights: {yields}Effect of DSE (E. pisciphila) on heavy metal tolerance of maize host was studied. {yields}DSE alleviated the deleterious effect of excessive heavy metals on maize. {yields}DSE restricted the transfer of heavy metals from the roots to shoots in maize. {yields}DSE colonization improved the tolerance of their host plants to heavy metals.

  13. Mixing of maize and wheat genomic DNA by somatic hybridization in regenerated sterile maize plants.

    Science.gov (United States)

    Szarka, B.; Göntér, I.; Molnár-Láng, M.; Mórocz, S.; Dudits, D.

    2002-07-01

    Intergeneric somatic hybridization was performed between albino maize ( Zea mays L.) protoplasts and mesophyll protoplasts of wheat ( Triticum aestivum L.) by polyethylene glycol (PEG) treatments. None of the parental protoplasts were able to produce green plants without fusion. The maize cells regenerated only rudimentary albino plantlets of limited viability, and the wheat mesophyll protoplasts were unable to divide. PEG-mediated fusion treatments resulted in hybrid cells with mixed cytoplasm. Six months after fusion green embryogenic calli were selected as putative hybrids. The first-regenerates were discovered as aborted embryos. Regeneration of intact, green, maize-like plants needed 6 months of further subcultures on hormone-free medium. These plants were sterile, although had both male and female flowers. The cytological analysis of cells from callus tissues and root tips revealed 56 chromosomes, but intact wheat chromosomes were not observed. Using total DNA from hybrid plants, three RAPD primer combinations produced bands resembling the wheat profile. Genomic in situ hybridization (GISH) using total wheat DNA as a probe revealed the presence of wheat DNA islands in the maize chromosomal background. The increased viability and the restored green color were the most-significant new traits as compared to the original maize parent. Other intermediate morphological traits of plants with hybrid origin were not found.

  14. 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.

  15. An improved method for chromosome counting in maize.

    Science.gov (United States)

    Kato, A

    1997-09-01

    An improved method for counting chromosomes in maize (Zea mays L.) is presented. Application of cold treatment (5C, 24 hr), heat treatment (42 C, 5 min) and a second cold treatment (5C, 24 hr) to root tips before fixation increased the number of condensed and dispersed countable metaphase chromosome figures. Fixed root tips were prepared by the enzymatic maceration-air drying method and preparations were stained with acetic orcein. Under favorable conditions, one preparation with 50-100 countable chromosome figures could be obtained in diploid maize using this method. Conditions affecting the dispersion of the chromosomes are described. This technique is especially useful for determining the somatic chromosome number in triploid and tetraploid maize lines.

  16. Making better maize plants for sustainable grain production in a changing climate.

    Science.gov (United States)

    Gong, Fangping; Wu, Xiaolin; Zhang, Huiyong; Chen, Yanhui; Wang, Wei

    2015-01-01

    Achieving grain supply security with limited arable land is a major challenge in the twenty-first century, owing to the changing climate and increasing global population. Maize plays an increasingly vital role in global grain production. As a C4 plant, maize has a high yield potential. Maize is predicted to become the number one cereal in the world by 2020. However, maize production has plateaued in many countries, and hybrid and production technologies have been fully exploited. Thus, there is an urgent need to shape maize traits and architectures for increased stress tolerance and higher yield in a changing climate. Recent achievements in genomics, proteomics, and metabolomics have provided an unprecedented opportunity to make better maize. In this paper, we discuss the current challenges and potential of maize production, particularly in China. We also highlight the need for enhancing maize tolerance to drought and heat waves, summarize the elite shoot and root traits and phenotypes, and propose an ideotype for sustainable maize production in a changing climate. This will facilitate targeted maize improvement through a conventional breeding program combined with molecular techniques.

  17. Economic Efficiency of Maize Production in Yola North Local ...

    African Journals Online (AJOL)

    user

    ABSTRACT. This study was carried out in Abeokuta, South-western Nigeria in 2008 and 2009 to assess the impact of tillage and poultry manure (PM) on soil infiltration rate and maize root growth. The experiment was a split-plot design with three replications. The main plot consisted of three tillage treatments: zero tillage.

  18. 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...

  19. Radiation preservation of maize

    International Nuclear Information System (INIS)

    Wasito.

    1980-01-01

    Radiation preservation of maize was carried out. Radiation doses and sources, shielding materials, packaging materials, chemical radiation effects, biological radiation effects, were discussed. Experimental methods, samples and accessories were also presented. (SMN)

  20. Maize (Zea mays L.).

    Science.gov (United States)

    Frame, Bronwyn; Warnberg, Katey; Main, Marcy; Wang, Kan

    2015-01-01

    Agrobacterium tumefaciens-mediated transformation is an effective method for introducing genes into maize. In this chapter, we describe a detailed protocol for genetic transformation of the maize genotype Hi II. Our starting plant material is immature embryos cocultivated with an Agrobacterium strain carrying a standard binary vector. In addition to step-by-step laboratory transformation procedures, we include extensive details in growing donor plants and caring for transgenic plants in the greenhouse.

  1. How are arbuscular mycorrhizal associations related to maize growth performance during short-term cover crop rotation?

    Science.gov (United States)

    Higo, Masao; Takahashi, Yuichi; Gunji, Kento; Isobe, Katsunori

    2018-03-01

    Better cover crop management options aiming to maximize the benefits of arbuscular mycorrhizal fungi (AMF) to subsequent crops are largely unknown. We investigated the impact of cover crop management methods on maize growth performance and assemblages of AMF colonizing maize roots in a field trial. The cover crop treatments comprised Italian ryegrass, wheat, brown mustard and fallow in rotation with maize. The diversity of AMF communities among cover crops used for maize management was significantly influenced by the cover crop and time course. Cover crops did not affect grain yield and aboveground biomass of subsequent maize but affected early growth. A structural equation model indicated that the root colonization, AMF diversity and maize phosphorus uptake had direct strong positive effects on yield performance. AMF variables and maize performance were related directly or indirectly to maize grain yield, whereas root colonization had a positive effect on maize performance. AMF may be an essential factor that determines the success of cover crop rotational systems. Encouraging AMF associations can potentially benefit cover cropping systems. Therefore, it is imperative to consider AMF associations and crop phenology when making management decisions. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  2. Usage of γ-ray treatment for productivity increasing of maize

    International Nuclear Information System (INIS)

    Ilieva, V.; Dimov, K.

    2003-01-01

    The aim of this study is to determine the influence of γ irradiation on phosphorus nutrition and maize productivity increasing. The vegetation experiment with irradiated and non-irradiated maize seeds in controlled conditions (moisture and temperature) for determination of phosphorus and phosphorus-gypsum absorption was carried out. The influence of γ irradiation on maize growth, export of mineral elements in maize, phosphorus fertilizing and dry biomass of maize plants are presented. The effect of the moisture of γ irradiated maize seeds (sort 'Knezha' - 3L - 621) on dry substance and yield of green mass is also discussed. Based on the presented experimental data the following conclusion have been made: the maize seeds (sort 'Knezha, hybrid H-708) simulation is useful; in all variants of phosphorus-gypsum absorption the increasing of plant mass yield (absolutely dry) is observed; the absorbed phosphates reserve is enhanced twice; the efficiency of 32 P use in stimulated seeds is higher than in non-stimulated seeds; the phosphorus content in maize (sort 'Knezha' - 2L - 611) is increasing mainly in leaves after X-ray irradiation (750 - 1500 R); γ irradiation (7.5 Gy) stimulate the root system (18%) and side roots development and drying up overcome

  3. Improvement of the soil nitrogen content and maize growth by earthworms and arbuscular mycorrhizal fungi in soils polluted by oxytetracycline.

    Science.gov (United States)

    Cao, Jia; Wang, Chong; Ji, Dingge

    2016-11-15

    Interactions between earthworms (Eisenia fetida) and arbuscular mycorrhizal fungi (Rhizophagus intraradices, AM fungi) have been suggested to improve the maize nitrogen (N) content and biomass and were studied in soils polluted by oxytetracycline (OTC). Maize was planted and amended with AMF and/or earthworms (E) in the soil with low (1mgkg(-1) soil DM) or high (100mgkg(-1) soil DM) amounts of OTC pollution in comparison to soil without OTC. The root colonization, shoot and root biomass, shoot and root N contents, soil nitrogen forms, ammonia-oxidizing bacteria (AOB) and archaea (AOA) were measured at harvest. The results indicated that OTC decreased maize shoot and root biomass (psoil urease activity and AOB and AOA abundance, which resulted in a lower N availability for maize roots and shoots. There was a significant interaction between earthworms and AM fungi on the urease activity in soil polluted by OTC (ppolluted soil by increasing the urease activity and relieving the stress from OTC on the soil N cycle. AM fungi and earthworms interactively increased maize shoot and root biomass (ppolluted soils through their regulation of the urease activity and the abundance of ammonia oxidizers, resulting in different soil NH4(+)-N and NO3(-)-N contents, which may contribute to the N content of maize shoots and roots. Earthworms and AM fungi could be used as an efficient method to relieve the OTC stress in agro-ecosystems. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Maize Endophytic Bacterial Diversity as Affected by Soil Cultivation History.

    Science.gov (United States)

    Correa-Galeote, David; Bedmar, Eulogio J; Arone, Gregorio J

    2018-01-01

    The bacterial endophytic communities residing within roots of maize ( Zea mays L.) plants cultivated by a sustainable management in soils from the Quechua maize belt (Peruvian Andes) were examined using tags pyrosequencing spanning the V4 and V5 hypervariable regions of the 16S rRNA. Across four replicate libraries, two corresponding to sequences of endophytic bacteria from long time maize-cultivated soils and the other two obtained from fallow soils, 793 bacterial sequences were found that grouped into 188 bacterial operational taxonomic units (OTUs, 97% genetic similarity). The numbers of OTUs in the libraries from the maize-cultivated soils were significantly higher than those found in the libraries from fallow soils. A mean of 30 genera were found in the fallow soil libraries and 47 were in those from the maize-cultivated soils. Both alpha and beta diversity indexes showed clear differences between bacterial endophytic populations from plants with different soil cultivation history and that the soils cultivated for long time requires a higher diversity of endophytes. The number of sequences corresponding to main genera Sphingomonas, Herbaspirillum, Bradyrhizobium and Methylophilus in the maize-cultivated libraries were statistically more abundant than those from the fallow soils. Sequences of genera Dyella and Sreptococcus were significantly more abundant in the libraries from the fallow soils. Relative abundance of genera Burkholderia, candidatus Glomeribacter, Staphylococcus, Variovorax, Bacillus and Chitinophaga were similar among libraries. A canonical correspondence analysis of the relative abundance of the main genera showed that the four libraries distributed in two clearly separated groups. Our results suggest that cultivation history is an important driver of endophytic colonization of maize and that after a long time of cultivation of the soil the maize plants need to increase the richness of the bacterial endophytes communities.

  5. Sm2, a paralog of the Trichoderma cerato-platanin elicitor Sm1, is also highly important for plant protection conferred by the fungal-root interaction of Trichoderma with maize.

    Science.gov (United States)

    Gaderer, Romana; Lamdan, Netta L; Frischmann, Alexa; Sulyok, Michael; Krska, Rudolf; Horwitz, Benjamin A; Seidl-Seiboth, Verena

    2015-01-16

    The proteins Sm1 and Sm2 from the biocontrol fungus Trichoderma virens belong to the cerato-platanin protein family. Members of this family are small, secreted proteins that are abundantly produced by filamentous fungi with all types of life-styles. Some species of the fungal genus Trichoderma are considered as biocontrol fungi because they are mycoparasites and are also able to directly interact with plants, thereby stimulating plant defense responses. It was previously shown that the cerato-platanin protein Sm1 from T. virens - and to a lesser extent its homologue Epl1 from Trichoderma atroviride - induce plant defense responses. The plant protection potential of other members of the cerato-platanin protein family in Trichoderma, however, has not yet been investigated. In order to analyze the function of the cerato-platanin protein Sm2, sm1 and sm2 knockout strains were generated and characterized. The effect of the lack of Sm1 and Sm2 in T. virens on inducing systemic resistance in maize seedlings, challenged with the plant pathogen Cochliobolus heterostrophus, was tested. These plant experiments were also performed with T. atroviride epl1 and epl2 knockout strains. In our plant-pathogen system T. virens was a more effective plant protectant than T. atroviride and the results with both Trichoderma species showed concordantly that the level of plant protection was more strongly reduced in plants treated with the sm2/epl2 knockout strains than with sm1/epl1 knockout strains. Although the cerato-platanin genes sm1/epl1 are more abundantly expressed than sm2/epl2 during fungal growth, Sm2/Epl2 are, interestingly, more important than Sm1/Epl1 for the promotion of plant protection conferred by Trichoderma in the maize-C. heterostrophus pathosystem.

  6. Breeding of speciality maize for industrial purposes

    OpenAIRE

    Pajić Zorica; Radosavljević Milica; Filipović Milomir; Todorović Goran; Srdić Jelena; Pavlov Milovan

    2010-01-01

    The breeding programme on speciality maize with specific traits was established at the Maize Research Institute, Zemun Polje, several decades ago. The initial material was collected, new methods applying to breeding of speciality maize, i.e. popping maize, sweet maize and white-seeded maize, were introduced. The aim was to enhance and improve variability of the initial material for breeding these three types of maize. Then, inbred lines of good combining abilities were developed and used as c...

  7. Ultrastructure of pea and cress root statocytes exposed to high gradient magnetic field

    Science.gov (United States)

    Belyavskaya, N. A.; Chernishov, V. I.; Polishchuk, O. V.; Kondrachuk, A. V.

    As it was demonstrated by Kuznetsov & Hasenstein (1996) the high gradient magnetic field (HGMF) can produce a ponderomotive force that results in displacements of amyloplasts and causes the root response similar to the graviresponse. It was suggested that the HGMF could allow to imitate the effects of gravity in microgravity and/or change them in laboratory conditions correspondingly, as well as to study statolith-related processes in graviperception. Therefore, the correlation between the direction of the ponderomotive force resulting in statolith displacements and the direction of the HGMF-induced plant curvature can be the serious argument to support this suggestion and needs the detailed ultrastructural analysis. Seeds of dicotyledon Pisum sativum L. cv. Damir-2 and monocotyledon Lepidium sativum L. cv. P896 were soaked and grown in a vertical position on moist filter paper in chambers at room temperature. Tips of primary roots of vertical control, gravistimulated and exposed to HGMF seedlings were fixed for electron microscopy using conventional techniques. At ultrastructural level, we observed no significant changes in the volume of the individual statocytes or amyloplasts, relative volumes of cellular organelles (except vacuoles), number of amyloplasts per statocyte or surface area of endoplasmic reticulum. No consistent contacts between amyloplasts and any cellular structures, including plasma membrane, were revealed at any stage of magneto- and gravistimulation. By 5 min after onset of magnetostimulation, amyloplasts were located along cell wall distant from magnets. In HGMF, the locations of amyloplasts in columella cells were similar to those in horizontally-oriented roots up to 1 h stimulation. In the latter case, there were sometimes cytoplasmic spherical bodies with a dense vesicle-rich cytoplasm in pea statocytes, which were absent in seedlings exposed to HGMF. In cress root statocytes, both gravi- and magnetostimulation were found to cause the

  8. Breeding of maize types with specific traits at the Maize Research Institute, Zemun Polje

    OpenAIRE

    Pajić Zorica

    2007-01-01

    Maize is primarily grown as an energy crop, but the use of different specific versions, such as high-oil maize, high-lysine maize, waxy maize, white-seeded maize, popping maize and sweet maize, is quite extensive. Speciality maize, due to its traits and genetic control of these traits, requires a particular attention in handling breeding material during the processes of breeding. It is especially related to prevention of uncontrolled pollination. In order to provide successful selection for a...

  9. Effect of rooting depth, plant density and planting date on maize (Zea Mays L.) yield and water use efficiency in semi-arid Zimbabwe: Modelling with AquaCrop

    NARCIS (Netherlands)

    Nyakudya, I.W.; Stroosnijder, L.

    2014-01-01

    Under low and poorly distributed rainfall higher food production can be achieved by increasing crop water use efficiency (WUE) through optimum soil fertility management and selection of deep-rooting cultivars, appropriate plant density and planting dates. We explored AquaCrop's applicability in

  10. 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.

  11. Root Exudate Effect on Germination and Mycelial Growth of ...

    African Journals Online (AJOL)

    The effect of some root exudates on the germination and mycelial growth of sclerotia of Sclerotium rolfsii Sacc. was studied. Root exudates of 5 – 10 days old seedlings from five plants viz: - tomato (Lycopersicum esculenta) maize (Zea mays), garden egg (Solanum melongena), pigeon pea (Cajanus cajan), and pepper ...

  12. Comparative impact of genetically modified and non modified maize (Zea mays L.) on succeeding crop and associated weed.

    Science.gov (United States)

    Ibrahim, Muhammad; Ahmed, Naseer; Ullah, Faizan; Shinwari, Zabta Khan; Bano, Asghari

    2016-04-01

    This research work documents the comparative impact of genetically modified (GM) (insect resistance) and non modified maize (Zea mays L.) on growth and germination of succeeding crop wheat (Triticum aestivum L.) and associated weed (Avena fatua L.). The aqueous extracts of both the GM and non-GM maize exhibited higher phenolic content than that of methanolic extracts. Germination percentage and germination index of wheat was significantly decreased by GM methanolic extract (10%) as well as that of non-GM maize at 3% aqueous extract. Similarly germination percentage of weed (Avena fatua L.) was significantly reduced by application of 3% and 5% methanolic GM extracts. All extracts of GM maize showed non-significant effect on the number of roots, root length and shoot length per plant but 5% and 10% methanolic extracts of non-GM maize significantly increased the number of roots per plant of wheat seedling. Similarly, 10% methanolic extract of GM maize significantly increased the number of roots per plant of weed seedling. Methanolic extracts of GM and non-GM maize (3% and 5%) significantly decreased the protease activity in wheat as compared to untreated control. © The Author(s) 2013.

  13. 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.

  14. Carbon sequestration in soils with annual inputs of maize biomass and maize-derived animal manure: Evidence from 13C abundance

    DEFF Research Database (Denmark)

    Thomsen, Ingrid Kaag; Christensen, Bent Tolstrup

    2010-01-01

    (beet roots, Beta vulgaris L.). After nine years of maize cropping, soil C from stubbles and roots accounted for 12 and 16% of the total-C in the LUN and ASK soil, respectively. Without additional organic amendment the content of total-C in the ASK soil remained constant and similar to that of soil...... biomass averaged 19% while the retention of C added in maize-derived faeces was 30%. Our study infers that that ruminant manure C contributes about 50% more to soil C sequestration than C applied in crop residues...

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

    Science.gov (United States)

    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.

  16. Biotechnology in maize breeding

    Directory of Open Access Journals (Sweden)

    Mladenović-Drinić Snežana

    2004-01-01

    Full Text Available Maize is one of the most important economic crops and the best studied and most tractable genetic system among monocots. The development of biotechnology has led to a great increase in our knowledge of maize genetics and understanding of the structure and behaviour of maize genomes. Conventional breeding practices can now be complemented by a number of new and powerful techniques. Some of these often referred to as molecular methods, enable scientists to see the layout of the entire genome of any organism and to select plants with preferred characteristics by "reading" at the molecular level, saving precious time and resources. DNA markers have provided valuable tools in various analyses ranging from phylogenetic analysis to the positional cloning of genes. Application of molecular markers for genetic studies of maize include: assessment of genetic variability and characterization of germ plasm, identification and fingerprinting of genotypes, estimation of genetic distance, detection of monogamic and quantitative trait loci, marker assisted selection, identification of sequence of useful candidate genes, etc. The development of high-density molecular maps which has been facilitated by PCR-based markers, have made the mapping and tagging of almost any trait possible and serve as bases for marker assisted selection. Sequencing of maize genomes would help to elucidate gene function, gene regulation and their expression. Modern biotechnology also includes an array of tools for introducing or deieting a particular gene or genes to produce plants with novel traits. Development of informatics and biotechnology are resulted in bioinformatic as well as in expansion of microarrey technique. Modern biotechnologies could complement and improve the efficiency of traditional selection and breeding techniques to enhance agricultural productivity.

  17. Chlordecone Transfer and Distribution in Maize Shoots.

    Science.gov (United States)

    Pascal-Lorber, Sophie; Létondor, Clarisse; Liber, Yohan; Jamin, Emilien L; Laurent, François

    2016-01-20

    Chlordecone (CLD) is a persistent organic pollutant (POP) that was mainly used as an insecticide against banana weevils in the French West Indies (1972-1993). Transfer of CLD via the food chain is now the major mechanism for exposure of the population to CLD. The uptake and the transfer of CLD were investigated in shoots of maize, a C4 model plant growing under tropical climates, to estimate the exposure of livestock via feed. Maize plants were grown on soils contaminated with [(14)C]CLD under controlled conditions. The greatest part of the radioactivity was associated with roots, nearly 95%, but CLD was detected in whole shoots, concentrations in old leaves being higher than those in young ones. CLD was thus transferred from the base toward the plant top, forming an acropetal gradient of contaminant. In contrast, results evidenced the existence of a basipetal gradient of CLD concentration within leaves whose extremities accumulated larger amounts of CLD because of evapotranspiration localization. Extractable residues accounted for two-thirds of total residues both in roots and in shoots. This study highlighted the fact that the distribution of CLD contamination within grasses resulted from a conjunction between the age and evapotranspiration rate of tissues. CLD accumulation in fodder may be the main route of exposure for livestock.

  18. Translocation of the neonicotinoid seed treatment clothianidin in maize.

    Science.gov (United States)

    Alford, Adam; Krupke, Christian H

    2017-01-01

    Neonicotinoid seed treatments, typically clothianidin or thiamethoxam, are routinely applied to >80% of maize (corn) seed grown in North America where they are marketed as a targeted pesticide delivery system. Despite this widespread use, the amount of compound translocated into plant tissue from the initial seed treatment to provide protection has not been reported. Our two year field study compared concentrations of clothianidin seed treatments in maize to that of maize without neonicotinoid seed treatments and found neonicotinoids present in root tissues up to 34 days post planting. Plant-bound clothianidin concentrations followed an exponential decay pattern with initially high values followed by a rapid decrease within the first ~20 days post planting. A maximum of 1.34% of the initial seed treatment was successfully recovered from plant tissues in both study years and a maximum of 0.26% was recovered from root tissue. Our findings show neonicotinoid seed treatments may provide protection from some early season secondary maize pests. However, the proportion of the neonicotinoid seed treatment clothianidin translocated into plant tissues throughout the growing season is low overall and this observation may provide a mechanism to explain reports of inconsistent efficacy of this pest management approach and increasing detections of environmental neonicotinoids.

  19. Translocation of the neonicotinoid seed treatment clothianidin in maize.

    Directory of Open Access Journals (Sweden)

    Adam Alford

    Full Text Available Neonicotinoid seed treatments, typically clothianidin or thiamethoxam, are routinely applied to >80% of maize (corn seed grown in North America where they are marketed as a targeted pesticide delivery system. Despite this widespread use, the amount of compound translocated into plant tissue from the initial seed treatment to provide protection has not been reported. Our two year field study compared concentrations of clothianidin seed treatments in maize to that of maize without neonicotinoid seed treatments and found neonicotinoids present in root tissues up to 34 days post planting. Plant-bound clothianidin concentrations followed an exponential decay pattern with initially high values followed by a rapid decrease within the first ~20 days post planting. A maximum of 1.34% of the initial seed treatment was successfully recovered from plant tissues in both study years and a maximum of 0.26% was recovered from root tissue. Our findings show neonicotinoid seed treatments may provide protection from some early season secondary maize pests. However, the proportion of the neonicotinoid seed treatment clothianidin translocated into plant tissues throughout the growing season is low overall and this observation may provide a mechanism to explain reports of inconsistent efficacy of this pest management approach and increasing detections of environmental neonicotinoids.

  20. Relationship between root growth, temperature and anion uptake

    Energy Technology Data Exchange (ETDEWEB)

    Holobrada, M; Mistrik, I; Kolek, J [Institute of Experimental Biology and Ecology of the Slovak Academy of Sciences, Bratislava (Czechoslovakia)

    1980-01-01

    The uptake and release were studied of /sup 35/S-sulfate ions by whole intact roots of maize seedlings. From the total incorporated sulfur only 20% were released back to the unlabelled culture solution. In correspondence to the physiological and biochemical-structural vertical gradient of the growing differentiating roots, the release of /sup 35/S from the apical root part was much lower than from the differentiated tissues.

  1. The relationship between root growth, temperature and anion uptake

    International Nuclear Information System (INIS)

    Holobrada, M.; Mistrik, I.; Kolek, J.

    1980-01-01

    The uptake and release were studied of 35 S-sulfate ions by whole intact roots of maize seedlings. From the total incorporated sulfur only 20% were released back to the unlabelled culture solution. In correspondence to the physiological and biochemical-structural vertical gradient of the growing differentiating roots, the release of 35 S from the apical root part was much lower than from the differentiated tissues. (author)

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

    Science.gov (United States)

    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

  3. Maize kernel evolution:From teosinte to maize

    Science.gov (United States)

    Maize is the most productive and highest value commodity in the US and around the world: over 1 billion tons were produced each year in 2013 and 2014. Together, maize, rice and wheat comprise over 60% of the world’s caloric intake, with wide regional variability in the importance of each crop. The i...

  4. Uptake, translocation, and toxicity of gold nanorods in maize

    Science.gov (United States)

    Moradi Shahmansouri, Nastaran

    Nanomaterials are widely used in many different products, such as electronics, cosmetics, industrial goods, biomedical uses, and other material applications. The heavy emission of nanomaterials into the environment has motived increasing concern regarding the effects on ecosystems, food chains, and, human health. Plants can tolerate a certain amount of natural nanomaterials, but large amounts of ENMs released from a variety of industries could be toxic to plants and possibly threaten the ecosystem. Employing phytoremediation as a contamination treatment method may show promise. However a pre-requisite to successful treatment is a better understanding of the behavior and effects of nanomaterials within plant systems. This study is designed to investigate the uptake, translocation, bioavailability, and toxicity of gold nanorods in maize plants. Maize is an important food and feed crop that can be used to understand the potential hazardous effects of nanoparticle uptake and distribution in the food chain. The findings could be an important contribution to the fields of phytoremediation, agri-nanotechnology, and nanoparticle toxicity on plants. In the first experiment, hydroponically grown maize seedlings were exposed to similar doses of commercial non-coated gold nanorods in three sizes, 10x34 nm, 20x75 nm, and 40x96 nm. The three nanorod species were suspended in solutions at concentrations of 350 mg/l, 5.8 mg/l, and 14 mg/l, respectively. Maize plants were exposed to all three solutions resulting in considerably lower transpiration and wet biomass than control plants. Likewise, dry biomass was reduced, but the effect is less pronounced than that of transpiration and wet biomass. The reduced transpiration and water content, which eventually proved fatal to exposed plants, were most likely a result of toxic effect of gold nanorod, which appeared to physically hinder the root system. TEM images proved that maize plants can uptake gold particles and accumulate them in

  5. Radiographing roots and shoots

    International Nuclear Information System (INIS)

    Shariffah Noor Khamseah Al Idid

    1985-01-01

    The effect of seed orientation on germination time and on shoot and root growth patterns is studied. Neutron radiography is used to observe the development of 4 types of plants, maize, greenpea, soya bean and padi. These plants were grown in varying orientations; sand sizes, sand thicknesses, and level of water content. Radiography of the seeds and plants were obtained for time exposure ranging from 3-12 hours and at reactor thermal power level, ranging from 500-750 kilowatts. Results obtained showed that seeds planted in varying orientations need different length of time for shoot emergence. Neutron radiography is now developed to other areas of non-industrial applications in Malaysia. (A.J.)

  6. Association and linkage analysis of aluminum tolerance genes in maize.

    Directory of Open Access Journals (Sweden)

    Allison M Krill

    Full Text Available BACKGROUND: Aluminum (Al toxicity is a major worldwide constraint to crop productivity on acidic soils. Al becomes soluble at low pH, inhibiting root growth and severely reducing yields. Maize is an important staple food and commodity crop in acidic soil regions, especially in South America and Africa where these soils are very common. Al exclusion and intracellular tolerance have been suggested as two important mechanisms for Al tolerance in maize, but little is known about the underlying genetics. METHODOLOGY: An association panel of 282 diverse maize inbred lines and three F2 linkage populations with approximately 200 individuals each were used to study genetic variation in this complex trait. Al tolerance was measured as net root growth in nutrient solution under Al stress, which exhibited a wide range of variation between lines. Comparative and physiological genomics-based approaches were used to select 21 candidate genes for evaluation by association analysis. CONCLUSIONS: Six candidate genes had significant results from association analysis, but only four were confirmed by linkage analysis as putatively contributing to Al tolerance: Zea mays AltSB like (ZmASL, Zea mays aluminum-activated malate transporter2 (ALMT2, S-adenosyl-L-homocysteinase (SAHH, and Malic Enzyme (ME. These four candidate genes are high priority subjects for follow-up biochemical and physiological studies on the mechanisms of Al tolerance in maize. Immediately, elite haplotype-specific molecular markers can be developed for these four genes and used for efficient marker-assisted selection of superior alleles in Al tolerance maize breeding programs.

  7. Randomly amplified polymorphic-DNA analysis for detecting genotoxic effects of Boron on maize (Zea mays L.).

    Science.gov (United States)

    Sakcali, M Serdal; Kekec, Guzin; Uzonur, Irem; Alpsoy, Lokman; Tombuloglu, Huseyin

    2015-08-01

    This study was carried out to investigate the genotoxic effect of boron (B) on maize using randomly amplified polymorphic DNA (RAPD) method. Experimental design was conducted under 0, 5, 10, 25, 50, 100, 125, and 150 ppm B exposures, and physiological changes have revealed a sharp decrease in root growth rates from 28% to 85%, starting from 25 ppm to 150 ppm, respectively. RAPD-polymerase chain reaction (PCR) analysis shows that DNA alterations are clearly observed from beginning to 100 ppm. B-induced inhibition in root growth had a positive correlation with DNA alterations. Total soluble protein, root and stem lengths, and B content analysis in root and leaves encourage these results as a consequence. These preliminary findings reveal that B causes chromosomal aberration and genotoxic effects on maize. Meanwhile, usage of RAPD-PCR technique is a suitable biomarker to detect genotoxic effect of B on maize and other crops for the future. © The Author(s) 2013.

  8. RESOURCE ALLOCATION IN A MAIZE BREEDING PROGRAM FOR NATIVE RESISTANCE TO WESTERN CORN ROOTWORM

    Directory of Open Access Journals (Sweden)

    Ivan Brkić

    2012-06-01

    Full Text Available The objective of this study was to determine the optimum allocation of the number of plants sampled per plot and number of locations and years required for screening maize genotypes for reduced root damage caused by western corn rootworm (WCR larvae, major pest of maize in Croatia, Europe and in the USA. Field trials were conducted on two locations Eastern Croatia, a major maize production area with natural WCR occurrence under continuous maize growing conditions. The trials were set as an incomplete lattice block design in two replications in 2007, 2008 and 2009 including 128 genotypes from various maize gene-pools. Our results suggest that the effect of year and respective interactions including year were the most important factors in maize breeding programs for native resistance to WCR. Thus, screening germplasm for WCR resistance should be made in a multi-year experiment, but not necessarily as a multi-location experiment. Resource optimization should be done by reducing number of roots per plot to minimum 4 sampled plants due to small within-plot environmental variance.

  9. Uptake of seed-applied copper by maize and the effects on seed vigor

    Directory of Open Access Journals (Sweden)

    Marcos Altomani Neves Dias

    2015-01-01

    Full Text Available Seed treatment is a low-cost and efficacious method to deliver a diversity of compounds to field crops. This study evaluated the uptake of seed-applied Cu by maize and the effect on seed vigor. The treatments were composed of a control (untreated seeds and five dosages of Cu: 0.11, 0.22, 0.44, 0.88 and 1.76 mg Cu seed–1, applied as cuprous oxide and copper oxychloride formulations. Seedling emergence and the speed of seedling emergence were determined in three periods: 1, 60 and 120 days after Cu application. Evaluations of root and shoot dry mass, Cu tissue concentration and efficiencies of Cu uptake and incorporation were conducted with two-leaf stage maize plants. Seed-applied Cu reduces the speed of maize seedling emergence, while the final emergence percentage is not affected. Shoot dry mass tends to increase with the application of Cu, while there is no interference on root dry mass within the dosages tested. Cu tissue concentration of both roots and shoots increases as higher dosages of Cu are applied to seeds, with higher accumulation in roots. Cuprous oxide promotes higher uptake of Cu by maize roots compared to copper oxychloride.

  10. Pilot study of nitrogen utilisation in maize

    International Nuclear Information System (INIS)

    Futo, I.; Palcsu, L.; Vodila, G.

    2012-01-01

    Complete text of publication follows. In the cooperation between KITE Ltd., Nadudvar, Hungary and the Hertelendi Laboratory of Environmental Studies, the aim was to determine the ideal locations of fertilising, the ideal distance of rows for the ideal production yield. To track the nitrogen utilisation of maize (Zea mays) 15 N enriched NH 4 NO 3 fertiliser was introduced among the usual fertilisers in the maize field of KITE Ltd. Nadudvar, Hungary on 30 th March 2012, before sowing. Four maize samples were taken from different areas of different fertiliser treatment (non-fertilised and non-labelled, fertilised and non-labelled, fertilised and labelled between the rows and fertilised and labelled within the rows) and from different development stages of the plant on 22 nd May, 8 th June, 6 th July and 7 th September being sampling periods 1-4, respectively. The plant samples were subsampled based on organs: root, stem and leaf. Samples were dried to constant mass and pulverised. The 15 N measurements were made by a Thermo Finnigan Delta PLUS XP isotope ratio mass spectrometer coupled with an elemental analyser. In case of non-fertilised and non-labelled plants, all the three organs were getting 15 N depleted with time, most intensively the stem and the less intensively the root (Figure 1). For the leaves and stems of the fertilised and non-labelled plants, the tendency in time is very similar to the ones of the non-fertilised and non-labelled plants, however, the roots of the fertilised and non-labelled plants got significantly enriched in the sample of September. In case of the fertilised and labelled between-the-rows samples, labelling is slightly seen as the delta values are positive. These values are significantly lower than the ones for the fertilised and labelled-within-the-rows plants. It is seen that fertiliser got to the vegetation in the largest extent in this layout. Labelling showed its maximum intensity in the second sampling (8 th June) showing that

  11. Maize variety and method of production

    Science.gov (United States)

    Pauly, Markus; Hake, Sarah; Kraemer, Florian J

    2014-05-27

    The disclosure relates to a maize plant, seed, variety, and hybrid. More specifically, the disclosure relates to a maize plant containing a Cal-1 allele, whose expression results in increased cell wall-derived glucan content in the maize plant. The disclosure also relates to crossing inbreds, varieties, and hybrids containing the Cal-1 allele to produce novel types and varieties of maize plants.

  12. 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....

  13. The Effect of Pollination on Cd Phytoextraction From Soil by Maize (Zea mays L.).

    Science.gov (United States)

    Xu, Wending; Lu, Guining; Wang, Rui; Guo, Chuling; Liao, Changjun; Yi, Xiaoyun; Dang, Zhi

    2015-01-01

    A pot experiment was conducted to investigate the effects of pollination on cadmium (Cd) phytoextraction from soil by mature maize plants. The results showed that the unpollinated maize plants accumulated 50% more Cd than that of the pollinated plants, even though the dry weight of the former plants was 15% less than that of the latter plants. The Cd accumulation in root and leaf of the unpollinated maize plant was 0.47 and 0.89 times higher than that of the pollinated plant, respectively. The Cd concentration in the cob was significantly decreased because of pollination. Preventing pollination is a promising approach for enhancing the effectiveness of phytoextraction in Cd-contaminated soils by maize. This study suggested that in low Cd-contaminated soil pollination should be encouraged because accumulation of Cd in maize grains is very little and maize seeds can bring farmers economic benefits, while in high Cd-contaminated soil, inhibition of pollination can be applied to enhance phytoextraction of Cd from soil by maize plant.

  14. Root systems and soil microbial biomass under no-tillage system

    Directory of Open Access Journals (Sweden)

    Venzke Filho Solismar de Paiva

    2004-01-01

    Full Text Available Some root parameters such as distribution, length, diameter and dry matter are inherent to plant species. Roots can influence microbial population during vegetative cycle through the rhizodeposits and, after senescence, integrating the soil organic matter pool. Since they represent labile substrates, especially regarding nitrogen, they can determine the rate of nutrient availability to the next crop cultivated under no-tillage (NT. The root systems of two crop species: maize (Zea mays L. cultivar Cargill 909 and soybean [Glycine max (L. Merr.] cultivar Embrapa 59, were compared in the field, and their influence on spatial distribution of the microbial C and N in a clayey-textured Typic Hapludox cultivated for 22 years under NT, at Tibagi, State of Paraná (PR, Brazil, was determined. Digital image processing and nail-plate techniques were used to evaluate 40 plots of a 80 ´ 50 ´ 3 cm soil profile. It was observed that 36% and 30% of the maize and soybeans roots, respectively, are concentrated in the 0 to 10 cm soil layer. The percent distribution of root dry matter was similar for both crops. The maize roots presented a total of 1,324 kg C ha-1 and 58 kg N ha-1, with higher root dry matter density and more roots in decomposition in the upper soil layer, decreasing with depth. The soybean roots (392 kg C ha-1 and 21 kg N ha-1 showed higher number of thinner roots and higher density per length unity compared to the maize. The maize roots enhanced microbial-C down to deeper soil layers than did the soybean roots. The microbial N presented a better correlation with the concentration of thin active roots and with roots in decomposition or in indefinite shape, possibly because of higher concentration of C and N easily assimilated by soil microorganisms.

  15. Advances in Maize Transformation Technologies and Development of Transgenic Maize.

    Science.gov (United States)

    Yadava, Pranjal; Abhishek, Alok; Singh, Reeva; Singh, Ishwar; Kaul, Tanushri; Pattanayak, Arunava; Agrawal, Pawan K

    2016-01-01

    Maize is the principal grain crop of the world. It is also the crop where genetic engineering has been employed to a great extent to improve its various traits. The ability to transform maize is a crucial step for application of gene technology in maize improvement. There have been constant improvements in the maize transformation technologies over past several years. The choice of genotype and the explant material to initiate transformation and the different types of media to be used in various stages of tissue culture can have significant impact on the outcomes of the transformation efforts. Various methods of gene transfer, like the particle bombardment, protoplast transformation, Agrobacterium -mediated, in planta transformation, etc., have been tried and improved over years. Similarly, various selection systems for retrieval of the transformants have been attempted. The commercial success of maize transformation and transgenic development is unmatched by any other crop so far. Maize transformation with newer gene editing technologies is opening up a fresh dimension in transformation protocols and work-flows. This review captures the various past and recent facets in improvement in maize transformation technologies and attempts to present a comprehensive updated picture of the current state of the art in this area.

  16. Root hair mutants of barley

    International Nuclear Information System (INIS)

    Engvild, K.C.; Rasmussen, K.

    2005-01-01

    Barley mutants without root hairs or with short or reduced root hairs were isolated among M 2 seeds of 'Lux' barley (Hordeum vulgare L.) after acidified sodium azide mutagenesis. Root hair mutants are investigated intensively in Arabidopsis where about 40 genes are known. A few root hair mutants are known in maize, rice, barley and tomato. Many plants without root hairs grow quite well with good plant nutrition, and mutants have been used for investigations of uptake of strongly bound nutrients like phosphorus, iron, zinc and silicon. Seed of 'Lux' barley (Sejet Plant Breeding, Denmark) were soaked overnight, and then treated with 1.5-millimolarsodium azide in 0.1 molar sodium phosphate buffer, pH 3, for 2.5 hours according to the IAEA Manual on Mutation Breeding (2nd Ed.). After rinsing in tap water and air-drying, the M 2 seeds were sown in the field the same day. Spikes, 4-6 per M 1 plant, were harvested. The mutation frequency was similar to that obtained with other barley cultivars from which low-phytate mutants were isolated [5]. Seeds were germinated on black filter paper in tap water for 3 or 4 days before scoring for root hair mutants

  17. Involvement of an antioxidant defense system in the adaptive response to cadmium in maize seedlings (Zea mays L.).

    Science.gov (United States)

    Xu, Xianghua; Liu, Cuiying; Zhao, Xiaoyan; Li, Renying; Deng, Wenjing

    2014-11-01

    Chemical and biological analyses were used to investigate the growth response and antioxidant defense mechanism of maize seedlings (Zea mays L.) grown in soils with 0-100 mg kg(-1) Cd. Results showed that maize seedlings have strong abilities to accumulate and tolerate high concentrations of Cd. For soil with 50 mg kg(-1) Cd, the Cd contents in roots and shoots of maize seedlings are as large as 295.6 and 153.0 mg kg(-1) DW, respectively, without visible symptoms of toxicity. Lower soil Cd concentrations lead to a decrease in reduced glutathione (GSH) content in leaves of maize seedlings, whereas higher soil Cd concentrations resulted in an increase in the activities of superoxide dismutase, guaiacol peroxidase, catalase, and ascorbate peroxidase. Maize seedlings have strong capacities to adapt to low concentrations of Cd by consuming GSH and to develop an antioxidative enzyme system to defend against high-Cd stress.

  18. Successive cultivation of maize and agricultural practices on root colonization, number of spores and species of arbuscular mycorrhizal fungi Cultivo sucessivo de milho e práticas agrícolas sobre a colonização radical, número de esporos e de espécies de fungos micorrízicos arbusculares

    Directory of Open Access Journals (Sweden)

    Rosilaine Carrenho

    2001-12-01

    Full Text Available A large number of propagules and a broad spectrum of species are two important components of ecosystem (including agroecosystem sustainability. Previous studies carried out in temperate areas showed that repeated monoculture leads to a decrease in the species abundance of arbuscular mycorrhizal fungi (AMF. This study evaluated the influence of maize monoculture and its agricultural practices on AMF during three consecutive cropping years in a Brazilian field. At the end of each cycle, soil and root samples were evaluated for species composition, spore populations and root colonization by AMF. The AMF community present during this period was scored according to the Spearman rank correlation and Principal Components Analysis. The mean percent root colonization values for the three cultivation periods were: 66.9, 60.7 and 70.5, respectively. Seven species were detected in the first year, Scutellospora persica being the most abundant (24.1% of spores and Glomus macrocarpum the most observed (100% of samples. In the second year, Glomus etunicatum was the species with the greatest number of spores (24.7% and, like G. macrocarpum, the most frequently observed (90% in a community of thirteen. In the third year, twenty-three AMF species were identified, Scutellospora sp. 1 being the most abundant (17.4%, and Gigaspora decipiens and Glomus claroideum the most frequent (both with a relative frequency of 70%. The main soil factors influencing root colonization and sporulation by AMF were pH (and related properties, phosphorus and organic matter contents.Elevado número de propágulos e de espécies são componentes importantes para manter a sustentabilidade dos ecossistemas, incluindo agrossistemas. Estudos desenvolvidos em áreas temperadas indicaram que monocultivo prolongado conduziu ao decréscimo na abundância de esporos e de espécies de fungos micorrízicos arbusculares (FMA. O presente estudo avaliou a influência da monocultura de milho e de suas

  19. MaizeGDB: The Maize Genetics and Genomics Database.

    Science.gov (United States)

    Harper, Lisa; Gardiner, Jack; Andorf, Carson; Lawrence, Carolyn J

    2016-01-01

    MaizeGDB is the community database for biological information about the crop plant Zea mays. Genomic, genetic, sequence, gene product, functional characterization, literature reference, and person/organization contact information are among the datatypes stored at MaizeGDB. At the project's website ( http://www.maizegdb.org ) are custom interfaces enabling researchers to browse data and to seek out specific information matching explicit search criteria. In addition, pre-compiled reports are made available for particular types of data and bulletin boards are provided to facilitate communication and coordination among members of the community of maize geneticists.

  20. Genetic resources in maize breeding

    Directory of Open Access Journals (Sweden)

    Anđelković Violeta

    2017-01-01

    Full Text Available Maize, wheat and rice are the most important cereals grown in the world. It is predicted that by 2025 maize is likely to become the crop with the greatest production globally. Conservation of maize germplasm provides the main resources for increased food and feed production. Conservation in gene banks (ex-situ is dominant strategy for maize conservation. More than 130 000 maize accessions, e.g. about 40% of total number, are stored in ten largest gene banks worldwide and Maize Research Institute Zemun Polje (MRIZP gene bank, with about 6000 accessions, is among them. Organized collecting missions started in 1961. in the former Yugoslavian territory, and up today, more than 2000 local maize landraces were stored. Pre-breeding activities that refer to identification of desirable traits from unadapted germplasm within genebank, result in materials expected to be included in breeding programs. Successful examples are LAMP, GEM and GENRES projects. At the end of XX century, at MRIZP genebank two pre-breeding activities were undertaken: eco-core and elite-core collections were created and landraces fulfilled particular criteria were chosen. In the last decade, MRIZP genebank collection was used for identification of sources for drought tolerance and improved grain quality. According to agronomic traits and general combining ability, two mini-core collections were created and included in commercial breeding programs.

  1. Effects of INH, DNP, 2, 4-D and CMU on the sugar content of the barley and maize leaves

    International Nuclear Information System (INIS)

    Fernandez, J.; Sancho, P.

    1979-01-01

    1 ppm of the chemicals in nutritive solution was absorbed by barley and maize roots during 24 and 48 hours in dark or light conditioners in order to determine the best conditions for the obtention of labelled sugars with high specific activity. Results show that the highest specific activity was obtained in maize plants treated with DNP for 24 hours in dark conditions. (Author) 51 refs

  2. Zealactones. Novel natural strigolactones from maize.

    Science.gov (United States)

    Charnikhova, Tatsiana V; Gaus, Katharina; Lumbroso, Alexandre; Sanders, Mark; Vincken, Jean-Paul; De Mesmaeker, Alain; Ruyter-Spira, Carolien P; Screpanti, Claudio; Bouwmeester, Harro J

    2017-05-01

    In the root exudate and root extracts of maize hybrid cv NK Falkone seven putative strigolactones were detected using UPLC-TQ-MS-MS. All seven compounds displayed MS-MS-fragmentation common for strigolactones and particularly the presence of a fragment of m/z 97 Da, which may indicate the presence of the so-called D-ring, suggests they are strigolactones. The levels of all these putative strigolactones increased upon phosphate starvation and decreased upon fluridone (carotenoid biosynthesis inhibitor) treatment, both of which are a common response for strigolactones. All seven compounds were subsequently isolated with prep-HPLC-MS. They all exhibited Striga hermonthica seed germination inducing activity just as the synthetic strigolactone analog GR24. The structure of two of the seven compounds was elucidated by NMR spectroscopy as: methyl (2E,3E)-4-(3,3-dimethyl-5-oxo-2-(prop-1-en-2-yl)tetrahydrofuran-2-yl)-2-(((4-methyl-5-oxo-2,5-dihydrofuran-2-yl)oxy)methylene)but-3-enoate (two diastereomers 1a and 1b). Strigolactones (1a/b) are closely related to the methyl ester of carlactonoic acid (MeCLA) and heliolactone. However, they contain a unique 4,4-dimethyltetrahydrofuran-2-one motif as the "A-ring" instead of the classical (di)methylcyclohexene. Because these compounds were isolated from maize (Zea mays) we called them "zealactone 1a and 1b". The implications of this discovery for our view on strigolactones and their biosynthesis are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Integration of root phenes revealed by intensive phenotyping of root system architecture, anatomy, and physiology in cereals

    Science.gov (United States)

    York, Larry

    2015-04-01

    Food insecurity is among the greatest challenges humanity will face in the 21st century. Agricultural production in much of the world is constrained by the natural infertility of soil which restrains crops from reaching their yield potential. In developed nations, fertilizer inputs pollute air and water and contribute to climate change and environmental degradation. In poor nations low soil fertility is a primary constraint to food security and economic development. Water is almost always limiting crop growth in any system. Increasing the acquisition efficiency of soil resources is one method by which crop yields could be increased without the use of more fertilizers or irrigation. Cereals are the most widely grown crops, both in terms of land area and in yield, so optimizing uptake efficiency of cereals is an important goal. Roots are the primary interface between plant and soil and are responsible for the uptake of soil resources. The deployment of roots in space and time comprises root system architecture (RSA). Cereal RSA is a complex phenotype that aggregates many elemental phenes (elemental units of phenotype). Integration of root phenes will be determined by interactions through their effects on soil foraging and plant metabolism. Many architectural, metabolic, and physiological root phenes have been identified in maize, including: nodal root number, nodal root growth angle, lateral root density, lateral root length, aerenchyma, cortical cell size and number, and nitrate uptake kinetics. The utility of these phenes needs confirmation in maize and in other cereals. The maize root system is composed of an embryonic root system and nodal roots that emerge in successive whorls as the plant develops, and is similar to other cereals. Current phenotyping platforms often ignore the inner whorls and instead focus on the most visible outer whorls after excavating a maize root crown from soil. Here, an intensive phenotyping platform evaluating phenes of all nodal root

  4. Characterization of stuA mutants in the mycotoxigenic maize pathogen Fusarium verticillioides

    Science.gov (United States)

    Fusarium verticillioides is a major pathogen of maize, causing root, stalk and ear rots and seedling blight. It also produces fumonisin mycotoxins. Ingestion of fumonisin-contaminated corn causes acute toxicity in livestock and is a potential carcinogen to humans. StuA, an APSES protein class transc...

  5. Growth and yield of cassava as influenced by maize and cowpea ...

    African Journals Online (AJOL)

    Two field trials were conducted at the research farm of the National Root Crops Research Institute (NRCRI) Umudike, Igbariam sub-station (060151N, 060521E) in 2013/2014 and 2014/2015 cropping seasons to determine the growth and yield of cassava as influenced by maize and cowpea population densities. Cassava at ...

  6. Aggressiveness of Cephalosporium maydis causing late wilt of maize in Spain.

    Science.gov (United States)

    García-Carneros, A B; Girón, I; Molinero-Ruiz, L

    2012-01-01

    Late wilt of maize, caused by the vascular and soilborne pathogen Cephalosporium maydis, was identified in the Iberian Peninsula in 2008. During the last years the incidence and economical impact of the disease has importantly increased both in Portugal and Spain. Varieties of maize displaying tolerance to the pathogen are available, but the effectiveness can be dependent on the virulence of the fungus (i.e. ability to cause disease on a specific genotype). On the other hand, strains of crop pathogens from different geographic origins can differ with regard to the degree of disease caused on a specific genotype (i.e. aggressiveness). Our working hypothesis was that isolates of C. maydis from different maize growing areas may differ in aggressiveness towards maize plants. Seven fungal strains were isolated in 2009 from diseased plants collected in the most important maize growing regions of Spain and used to inoculate two susceptible maize varieties grown in shadehouse from March to July 2010. The experimental unit consisted of two 4-day-old seedlings planted in an 8-liter pot filled with sand/silt previously infested with 200 g of wheat grains colonized by the fungi. Non colonized wheat grains were used for the control treatments. Six replications (pots) were established for each variety/isolate combination according to a complete randomized 2 x 8 factorial design. The percentage of necrotic and dry aboveground tissues was recorded 14 weeks after inoculation and thereafter weekly until physiological senescence of the control plants. At the end of the experiment, weights of roots and aboveground parts of the plants were recorded. Initial occurrence of symptoms in the plants was significantly dependent on the isolate of C. maydis and on the maize variety. However, final severity of aboveground symptoms (leaf necroses and drying up) was only dependent on the fungal isolate. All the isolates significantly reduced the root weight of both varieties of maize. The highest

  7. 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...

  8. Breeding of maize types with specific traits at the Maize Research Institute, Zemun Polje

    Directory of Open Access Journals (Sweden)

    Pajić Zorica

    2007-01-01

    Full Text Available Maize is primarily grown as an energy crop, but the use of different specific versions, such as high-oil maize, high-lysine maize, waxy maize, white-seeded maize, popping maize and sweet maize, is quite extensive. Speciality maize, due to its traits and genetic control of these traits, requires a particular attention in handling breeding material during the processes of breeding. It is especially related to prevention of uncontrolled pollination. In order to provide successful selection for a certain trait, the following specific procedures in evaluation of the trait are necessary: the estimation of a popping volume and flake quality in popping maize; the determination of sugars and harvest maturity in sweet maize; the determination of oil in selected samples of high-oil maize types, and so forth. Breeding programmes for speciality maize, except high-amylose maize, have been implemented at the Maize Research Institute, Zemun Polje, Belgrade, for the last 45 years. A great number of high-yielding sweet maize hybrids, popping maize, high-oil and high-lysine, flint and white-seeded maize hybrids were developed during this 45-year period. Auspicious selection and breeding for these traits is facilitated by the abundant genetic variability and technical and technological possibilities necessary for successful selection.

  9. Deregulation of Lesotho's maize market

    OpenAIRE

    van Schalkwyk, Herman D.; van Zyl, Johan; Botha, P.W.; Bayley, B.

    1997-01-01

    During the past year, there have been major policy reforms in Lesotho and South Africa with respect to maize pricing and marketing. In Lesotho the impact of deregulation on producers, consumers and government revenues was substantially lower than it should have been, and as a result Lesotho was not able to reap the full benefits of these changes. This is partly because information on the changes to the maize marketing system did not reach the potential beneficiaries of the new system. Free an...

  10. Rhizosphere acidification of faba bean, soybean and maize

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, L.L. [College of Resources and Environmental Sciences, China Agricultural University, Key Laboratory of Plant and Soil Interactions, Ministry of Education, Beijing, 100094 (China); Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, 100094 (China); Cao, J. [School of Life Science, Key Laboratory of Arid and Grassland Ecology, Lanzhou University, Lanzhou 730000 (China); Zhang, F.S. [College of Resources and Environmental Sciences, China Agricultural University, Key Laboratory of Plant and Soil Interactions, Ministry of Education, Beijing, 100094 (China); Li, L., E-mail: lilong@cau.edu.cn [College of Resources and Environmental Sciences, China Agricultural University, Key Laboratory of Plant and Soil Interactions, Ministry of Education, Beijing, 100094 (China)

    2009-07-01

    Interspecific facilitation on phosphorus uptake was observed in faba bean/maize intercropping systems in previous studies. The mechanism behind this, however, remained unknown. Under nitrate supply, the difference in rhizosphere acidification potential was studied by directly measuring pH of the solution and by visualizing and quantifying proton efflux of roots between faba bean (Vicia faba L. cv. Lincan No.5), soybean (Glycine max L. cv. Zhonghuang No. 17) and maize (Zea mays L. cv. Zhongdan No.2) in monoculture and intercrop, supplied without or with 0.2 mmol L{sup -1} P as KH{sub 2}PO{sub 4}. The pH of the nutrient solution grown faba bean was lower than initial pH of 6.0 from day 1 to day 22 under P deficiency, whereas the pH of the solution with maize was declined from day 13 after treatment. Growing soybean increased solution pH irrespective of P supply. Under P deficiency, the proton efflux of faba bean both total (315.25 nmol h{sup -1} plant{sup -1}) and specific proton efflux (0.47 nmol h{sup -1} cm{sup -1}) was greater than that those of soybean (21.80 nmol h{sup -1} plant{sup -1} and 0.05 nmol h{sup -1} cm{sup -1}, respectively). Faba bean had much more ability of rhizosphere acidification than soybean and maize. The result can explain partly why faba bean utilizes sparingly soluble P more effectively than soybean and maize do, and has an important implication in understanding the mechanism behind interspecific facilitation on P uptake by intercropped species.

  11. Zinc solubilizing Bacillus spp. potential candidates for biofortification in maize.

    Science.gov (United States)

    Mumtaz, Muhammad Zahid; Ahmad, Maqshoof; Jamil, Moazzam; Hussain, Tanveer

    2017-09-01

    Bioaugmentation of Zn solubilizing rhizobacteria could be a sustainable intervention to increase bioavailability of Zn in soil which can be helpful in mitigation of yield loss and malnutrition of zinc. In present study, a number of pure rhizobacterial colonies were isolated from maize rhizosphere and screened for their ability to solubilize zinc oxide. These isolates were screened on the basis of zinc and phosphate solubilization, IAA production, protease production, catalase activity and starch hydrolysis. All the selected isolates were also positive for oxidase activity (except ZM22), HCN production (except ZM27) and utilization of citrate. More than 70% of isolates produces ammonia, hydrogen cyanide, siderophores, exopolysaccharides and cellulase. More than half of isolates also showed potential for urease activity and production of lipase. The ZM31 and S10 were the only isolates which showed the chitinase activity. All these isolates were evaluated in a jar trial for their ability to promote growth of maize under axenic conditions. Results revealed that inoculation of selected zinc solubilizing rhizobacterial isolates improved the growth of maize. In comparison, isolates ZM20, ZM31, ZM63 and S10 were best compared to other tested isolates in stimulating the growth attributes of maize like shoot length, root length, plant fresh and dry biomass. These strains were identified as Bacillus sp. (ZM20), Bacillus aryabhattai (ZM31 and S10) and Bacillus subtilis (ZM63) through 16S rRNA sequencing. This study indicated that inoculation of Zn solubilizing strains have potential to promote growth and can be the potential bio-inoculants for biofortification of maize to overcome the problems of malnutrition. Copyright © 2017 Elsevier GmbH. All rights reserved.

  12. Difference between resistant and susceptible maize to systematic colonization as revealed by DsRed-labeled Fusarium verticillioides

    Directory of Open Access Journals (Sweden)

    Lei Wu

    2013-10-01

    Full Text Available Fusarium verticillioides was labeled with DsRed via Agrobacterium tumefaciens-mediated transformation to examine differences in colonization and reactions of resistant and susceptible inbred lines of maize (Zea mays L.. The extent of systemic colonization of F. verticillioides in roots from maize lines either resistant or susceptible to the fungus was studied by visualizing the red fluorescence produced by the fungus expressing DsRed. The difference in quantities of colony forming units (CFU in roots and basal stems, production of fumonisin B1, and pH of root were determined. Although F. verticillioides colonized both resistant and susceptible lines, differences were observed in the pattern and extent of fungal colonization in the two types of maize lines. The fungus colonized the susceptible lines producing mosaic patterns by filling the individual root cells with hyphae. Such a pattern of colonization was rarely observed in resistant lines, which were less colonized by the fungus than the susceptible lines in terms of CFUs. The production of mycotoxin fumonisin B1 in roots from different lines was closely correlated with the amount of F. verticillioides colonization, rather than the pH or amylopectin concentrations in the root. The findings from this study contribute to a better understanding of the defense mechanism in resistant maize lines to F. verticillioides.

  13. Application of electrical capacitance measurement for in situ monitoring of competitive interactions between maize and weed plants

    Energy Technology Data Exchange (ETDEWEB)

    Cseresnyés, I.; Takács, T.; Füzy, A.; Végh, K.R.; Lehoczky, E.

    2016-11-01

    Applicability of root electrical capacitance (EC) measurement for monitoring of crop–weed competition was studied in a pot experiment. Maize (Zea mays L.) was grown both alone and with Echinochloa crus-galli or Abutilon theophrasti in different densities with regular measurement of root EC. Plants were harvested 42 days after planting to determine above- and belowground biomass. Depending on weed density, E. crus-galli-A. theophrasti interaction reduced the root EC of maize by 22–66% and 3–57%, respectively. Competitive effect of crop on weeds and intraspecific competition among weeds could also be detected by EC values: E. crus-galli was less sensitive both to the presence of maize and to intraspecific competition than A. theophrasti. Strong linear correlations between root dry mass and root EC for crop and weeds (with R2 from 0.901 to 0.956) were obtained by regression analyses at the end of the experiment. EC monitoring informed us on the emergence time of competition: E. crus-galli interfered with maize root growth a week earlier then A. theophrasti, and increasing weed densities accelerated the emergence of competition. In conclusion, the simple, non-destructive EC method should be considered a potential in situ technique for pot studies on crop–weed competition, which may partially substitute the intrusive techniques commonly used in agricultural researches. (Author)

  14. Allocation and source attribution of lead and cadmium in maize (Zea mays L.) impacted by smelting emissions

    International Nuclear Information System (INIS)

    Bi Xiangyang; Feng Xinbin; Yang Yuangen; Li Xiangdong; Shin, Grace P.Y.; Li Feili; Qiu Guangle; Li Guanghui; Liu Taoze; Fu Zhiyou

    2009-01-01

    Plants grown in contaminated areas may accumulate trace metals to a toxic level via their roots and/or leaves. In the present study, we investigated the distribution and sources of Pb and Cd in maize plants (Zea mays L.) grown in a typical zinc smelting impacted area of southwestern China. Results showed that the smelting activities caused significantly elevated concentrations of Pb and Cd in the surrounding soils and maize plants. Pb isotope data revealed that the foliar uptake of atmospheric Pb was the dominant pathway for Pb to the leaf and grain tissues of maize, while Pb in the stalk and root tissues was mainly derived from root uptake. The ratio of Pb to Cd concentrations in the plants indicated that Cd had a different behavior from Pb, with most Cd in the maize plants coming from the soil via root uptake. - The sources and pathways of Pb and Cd accumulated in maize were assessed using Pb isotopes and Pb/Cd ratios

  15. Allocation and source attribution of lead and cadmium in maize (Zea mays L.) impacted by smelting emissions

    Energy Technology Data Exchange (ETDEWEB)

    Bi Xiangyang [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Key Laboratory of Biogeology and Environmental Geology, Ministry of Education, China University of Geosciences, Wuhan 430074 (China); Feng Xinbin [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China)], E-mail: fengxinbin@vip.skleg.cn; Yang Yuangen [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Li Xiangdong; Shin, Grace P.Y. [Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Li Feili [College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032 (China); Qiu Guangle; Li Guanghui; Liu Taoze; Fu Zhiyou [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China)

    2009-03-15

    Plants grown in contaminated areas may accumulate trace metals to a toxic level via their roots and/or leaves. In the present study, we investigated the distribution and sources of Pb and Cd in maize plants (Zea mays L.) grown in a typical zinc smelting impacted area of southwestern China. Results showed that the smelting activities caused significantly elevated concentrations of Pb and Cd in the surrounding soils and maize plants. Pb isotope data revealed that the foliar uptake of atmospheric Pb was the dominant pathway for Pb to the leaf and grain tissues of maize, while Pb in the stalk and root tissues was mainly derived from root uptake. The ratio of Pb to Cd concentrations in the plants indicated that Cd had a different behavior from Pb, with most Cd in the maize plants coming from the soil via root uptake. - The sources and pathways of Pb and Cd accumulated in maize were assessed using Pb isotopes and Pb/Cd ratios.

  16. Transfer of 65Zn in maize -mycorrhizal systems: a potential mechanism to alleviate Zn deficiency in maize

    International Nuclear Information System (INIS)

    Subramanian, K.S.; Tenshia, Virgin

    2017-01-01

    Mycorrhizas are root associated fungi and obligate symbionts known to improve the nutritional status of the host plant as a direct consequence of transfer of slowly diffusing nutrients such as zinc. The Zn use efficiency by crops hardly exceeds 2-5 per cent and major portion of the Zn gets accumulated in soil in various pools which are not available to plants. Further, mycorrhizal symbiosis alters the chemical and biochemical properties of rhizosphere that affect the isotopic parameters such as A value, E value and L value. These parameters were measured for both mycorrhizal and non-mycorrhizal maize plants. A pot culture experiment was conducted to determine the availability of Zn using isotopic dilution techniques. Maize plants were grown in pots inoculated with (M+) or without (M-) mycorrhizal fungus Glomus intraradices. Tagged 65 ZnSO 4 was applied to soil at the time of sowing

  17. 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

  18. Bacterial communities in the rhizosphere of amilaceous maize (Zea mays L. as assessed by pyrosequencing

    Directory of Open Access Journals (Sweden)

    David Correa-Galeote

    2016-07-01

    Full Text Available Maize (Zea mays L. is the staple diet of the native peasants in the Quechua region of the Peruvian Andes who continue growing it in small plots called chacras following ancestral traditions. The abundance and structure of bacterial communities associated with the roots of amilaceous maize has not been studied in Andean chacras. Accordingly, the main objective of this study was to describe the rhizospheric bacterial diversity of amilaceous maize grown either in the presence or the absence of bur clover cultivated in soils from the Quechua maize belt. Three 16S rRNA gene libraries, one corresponding to sequences of bacteria from bulk soil of a chacra maintained under fallow conditions, the second from the rhizosphere of maize-cultivated soils, and the third prepared from rhizospheric soil of maize cultivated in intercropping with bur clover were examined using pyrosequencing tags spanning the V4 and V5 hypervariable regions of the gene. A total of 26031 sequences were found that grouped into 5955 distinct operational taxonomic units which distributed in 309 genera. The numbers of OTUs in the libraries from the maize-cultivated soils were significantly higher than those found in the libraries from bulk soil. One hundred ninety seven genera were found in the bulk soil library and 234 and 203 were in those from the maize and maize/bur clover-cultivated soils. Sixteen out of the 309 genera had a relative abundance higher than 0.5% and the were (in decreasing order of abundance Gp4, Gp6, Flavobacterium, Subdivision3 genera incertae sedis of the Verrucomicrobia phylum, Gemmatimonas, Dechloromonas, Ohtaekwangia, Rhodoferax, Gaiella, Opitutus, Gp7, Spartobacteria genera incertae sedis, Terrimonas, Gp5, Steroidobacter and Parcubacteria genera incertae sedis. Genera Gp4 and Gp6 of the Acidobacteria, Gemmatimonas and Rhodoferax were the most abundant in bulk soil, whereas Flavobacterium, Dechloromonas and Ohtaekwangia were the main genera in the rhizosphere

  19. Impact of chelator-induced phytoextraction of cadmium on yield and ionic uptake of maize.

    Science.gov (United States)

    Anwar, Sumera; Khan, Shahbaz; Ashraf, M Yasin; Noman, Ali; Zafar, Sara; Liu, Lijun; Ullah, Sana; Fahad, Shah

    2017-06-03

    Enhanced phytoextraction uses soil chelators to increase the bioavailability of heavy metals. This study tested the effectiveness of ethylenediaminetetraacetic acid (EDTA) and citric acid in enhancing cadmium (Cd) phytoextraction and their effects on the growth, yield, and ionic uptake of maize (Zea mays). Maize seeds of two cultivars were sown in pots treated with 15 (Cd 15 ) or 30 mg Cd kg -1 soil (Cd 30 ). EDTA and citric acid at 0.5 g kg -1 each were applied 2 weeks after germination. Results demonstrated that the growth, yield per plant, and total grain weight were reduced by exposure to Cd. EDTA increased the uptake of Cd in shoots, roots, and grains of both maize varieties. Citric acid did not enhance the uptake of Cd, rather it ameliorated the toxicity of Cd, as shown by increased shoot and root length and biomass. Cadmium toxicity reduced the number of grains, rather than the grain size. The maize cultivar Sahiwal-2002 extracted 1.6% and 3.6% of Cd from soil in both Cd+ EDTA treatments. Hence, our study implies that maize can be used to successfully phytoremediate Cd from soil using EDTA, without reducing plant biomass or yield.

  20. IMAZAPYR-RESISTANT MAIZE TECHNOLOGY ADOPTION FOR ...

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    decisions by protecting maize (Zea mays L.) crop in western Kenya from Striga. Key Words: Adopters, Zea ... Africa, efficient and profitable production of maize is severely constrained by ..... gap by understanding its source. African. Journal of ...

  1. Overestimation of Crop Root Biomass in Field Experiments Due to Extraneous Organic Matter.

    Science.gov (United States)

    Hirte, Juliane; Leifeld, Jens; Abiven, Samuel; Oberholzer, Hans-Rudolf; Hammelehle, Andreas; Mayer, Jochen

    2017-01-01

    Root biomass is one of the most relevant root parameters for studies of plant response to environmental change, soil carbon modeling or estimations of soil carbon sequestration. A major source of error in root biomass quantification of agricultural crops in the field is the presence of extraneous organic matter in soil: dead roots from previous crops, weed roots, incorporated above ground plant residues and organic soil amendments, or remnants of soil fauna. Using the isotopic difference between recent maize root biomass and predominantly C3-derived extraneous organic matter, we determined the proportions of maize root biomass carbon of total carbon in root samples from the Swiss long-term field trial "DOK." We additionally evaluated the effects of agricultural management (bio-organic and conventional), sampling depth (0-0.25, 0.25-0.5, 0.5-0.75 m) and position (within and between maize rows), and root size class (coarse and fine roots) as defined by sieve mesh size (2 and 0.5 mm) on those proportions, and quantified the success rate of manual exclusion of extraneous organic matter from root samples. Only 60% of the root mass that we retrieved from field soil cores was actual maize root biomass from the current season. While the proportions of maize root biomass carbon were not affected by agricultural management, they increased consistently with soil depth, were higher within than between maize rows, and were higher in coarse (>2 mm) than in fine (≤2 and >0.5) root samples. The success rate of manual exclusion of extraneous organic matter from root samples was related to agricultural management and, at best, about 60%. We assume that the composition of extraneous organic matter is strongly influenced by agricultural management and soil depth and governs the effect size of the investigated factors. Extraneous organic matter may result in severe overestimation of recovered root biomass and has, therefore, large implications for soil carbon modeling and estimations

  2. 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

  3. A Maize Inbred Exhibits Resistance Against Western Corn Rootwoorm, Diabrotica virgifera virgifera.

    Science.gov (United States)

    Castano-Duque, Lina; Loades, Kenneth W; Tooker, John F; Brown, Kathleen M; Paul Williams, W; Luthe, Dawn S

    2017-12-01

    Insect resistance against root herbivores like the western corn rootworm (WCR, Diabrotica virgifera virgifera) is not well understood in non-transgenic maize. We studied the responses of two American maize inbreds, Mp708 and Tx601, to WCR infestation using biomechanical, molecular, biochemical analyses, and laser ablation tomography. Previous studies performed on several inbreds indicated that these two maize genotypes differed in resistance to pests including fall armyworm (Spodoptera frugiperda) and WCR. Our data confirmed that Mp708 shows resistance against WCR, and demonstrates that the resistance mechanism is based in a multi-trait phenotype that includes increased resistance to cutting in nodal roots, stable root growth during insect infestation, constitutive and induced expression of known herbivore-defense genes, including ribosomal inhibitor protein 2 (rip2), terpene synthase 23 (tps23) and maize insect resistance cysteine protease-1 (mir1), as well high constitutive levels of jasmonic acid and production of (E)-β-caryophyllene. In contrast, Tx601 is susceptible to WCR. These findings will facilitate the use of Mp708 as a model to explore the wide variety of mechanisms and traits involved in plant defense responses and resistance to herbivory by insects with several different feeding habits.

  4. Lumbricus terrestris L. activity increases the availability of metals and their accumulation in maize and barley

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, E. [Department of Chemical Engineering, School of Civil Engineering, University of Castilla-La Mancha, Avenida Camilo Jose Cela, s/n, 13071 Ciudad Real (Spain); Alonso-Azcarate, J. [Department of Physical Chemistry, Faculty of Environmental Sciences, University of Castilla-La Mancha, Avenida Carlos III, s/n, 45071 Toledo (Spain); Rodriguez, L., E-mail: Luis.Rromero@uclm.es [Department of Chemical Engineering, School of Civil Engineering, University of Castilla-La Mancha, Avenida Camilo Jose Cela, s/n, 13071 Ciudad Real (Spain)

    2011-03-15

    The effect of the earthworm Lumbricus terrestris L. on metal availability in two mining soils was assessed by means of chemical extraction methods and a pot experiment using crop plants. Results from single and sequential extractions showed that L. terrestris had a slight effect on metal fractionation in the studied soils: only metals bound to the soil organic matter were significantly increased in some cases. However, we found that L. terrestris significantly increased root, shoot and total Pb and Zn concentrations in maize and barley for the soil with the highest concentrations of total and available metals. Specifically, shoot Pb concentration was increased by a factor of 7.5 and 3.9 for maize and barley, respectively, while shoot Zn concentration was increased by a factor of 3.7 and 1.7 for maize and barley, respectively. Our results demonstrated that earthworm activity increases the bioavailability of metals in soils. - Research highlights: > Lumbricus terrestris L. activity increases the bioavailability of metals in soils. > Earthworm activity can significantly increase total, shoot and root metal concentrations for crop plants. > Both bioassays and chemical extraction methods are necessary for assessing the bioavailability of metals in contaminated soils. - Lumbricus terrestris L. activity increases the bioavailability of metals in soils and total, shoot and root metal concentrations for maize and barley.

  5. Lumbricus terrestris L. activity increases the availability of metals and their accumulation in maize and barley

    International Nuclear Information System (INIS)

    Ruiz, E.; Alonso-Azcarate, J.; Rodriguez, L.

    2011-01-01

    The effect of the earthworm Lumbricus terrestris L. on metal availability in two mining soils was assessed by means of chemical extraction methods and a pot experiment using crop plants. Results from single and sequential extractions showed that L. terrestris had a slight effect on metal fractionation in the studied soils: only metals bound to the soil organic matter were significantly increased in some cases. However, we found that L. terrestris significantly increased root, shoot and total Pb and Zn concentrations in maize and barley for the soil with the highest concentrations of total and available metals. Specifically, shoot Pb concentration was increased by a factor of 7.5 and 3.9 for maize and barley, respectively, while shoot Zn concentration was increased by a factor of 3.7 and 1.7 for maize and barley, respectively. Our results demonstrated that earthworm activity increases the bioavailability of metals in soils. - Research highlights: → Lumbricus terrestris L. activity increases the bioavailability of metals in soils. → Earthworm activity can significantly increase total, shoot and root metal concentrations for crop plants. → Both bioassays and chemical extraction methods are necessary for assessing the bioavailability of metals in contaminated soils. - Lumbricus terrestris L. activity increases the bioavailability of metals in soils and total, shoot and root metal concentrations for maize and barley.

  6. Herbaspirillum seropedicae rfbB and rfbC genes are required for maize colonization.

    Science.gov (United States)

    Balsanelli, Eduardo; Serrato, Rodrigo V; de Baura, Valter A; Sassaki, Guilherme; Yates, Marshall G; Rigo, Liu Un; Pedrosa, Fábio O; de Souza, Emanuel M; Monteiro, Rose A

    2010-08-01

    In this study we disrupted two Herbaspirillum seropedicae genes, rfbB and rfbC, responsible for rhamnose biosynthesis and its incoporation into LPS. GC-MS analysis of the H. seropedicae wild-type strain LPS oligosaccharide chain showed that rhamnose, glucose and N-acetyl glucosamine are the predominant monosaccharides, whereas rhamnose and N-acetyl glucosamine were not found in the rfbB and rfbC strains. The electrophoretic pattern of the mutants LPS was drastically altered when compared with the wild type. Knockout of rfbB or rfbC increased the sensitivity towards SDS, polymyxin B sulfate and salicylic acid. The mutants attachment capacity to maize root surface plantlets was 100-fold lower than the wild type. Interestingly, the wild-type capacity to attach to maize roots was reduced to a level similar to that of the mutants when the assay was performed in the presence of isolated wild-type LPS, glucosamine or N-acetyl glucosamine. The mutant strains were also significantly less efficient in endophytic colonization of maize. Expression analysis indicated that the rfbB gene is upregulated by naringenin, apigenin and CaCl(2). Together, the results suggest that intact LPS is required for H. seropedicae attachment to maize root and internal colonization of plant tissues. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

  7. Assessing the effect of phosphorus application on early growth of maize at Sunderbazar, Lamjung, Nepal

    Directory of Open Access Journals (Sweden)

    Ram Kumar Shrestha

    2016-12-01

    Full Text Available Phosphorus (P is an essential nutrient element for maize production. A pot experiment was conducted during May-June, 2015 to assess the effects of different rates of P on early growth of maize plant at Sundarbazar, Lamjung. Two maize varieties (Rato Makai and Poshilo Makai-1 were subjected to four P levels (0 kg ha-1, 13 kg ha-1, 18 kg ha-1, and 23 kg ha-1 in randomized complete block design with four replications. The effects of different P level on root elongation, root biomass, plant height, root shoot biomass ratio and total dry matter were investigated at 45 days after sowing. For all parameters, the maximum value was obtained when soil was added with 18 kg P ha-1 & the minimum value under the control of 0 kg P ha-1. Maize varieties differed significantly in terms of all the parameters under study, and Poshilo Makai-1 performed better than Rato Makai at all P levels. So, from this result, it can be concluded that Poshilo Makai-1 appeared to be P efficient over Rato Makai at early growth stage. However, it would be necessary to look at the response of crop up to maturity and at wider range of P to have the better insight of their relative performance.

  8. Biochemical markers of embryogenesis in tissue cultures of the maize inbred B73

    International Nuclear Information System (INIS)

    Everett, N.P.; Wach, M.J.; Ashworth, D.J.

    1985-01-01

    Stable embryogenic, organogenic and undifferentiated cell lines of the maize (Zea mays L.) inbred B73 were used to assess the value of using isozyme analyses and the composition of secreted polysaccharides to identify embryogenic cells. Esterase, glutamate dehydrogenase, alcohol dehydrogenase and β-glucosidase all possessed developmentally regulated isozymes but only esterase and glutamate dehydrogenase could be used to distinguish between embryogenic and shoot-forming cultures. Embryogenic callus and suspension cultures secreted a mucilagenous polysaccharide whose production was stimulated by 2, 4-dichlorophenozyacetic acid (2, 4-D). The polysaccharide was different from root slime and corn hull gum and may be related to the 'cementing layer' in maize kernels (author)

  9. SOIL WATER BALANCE APPROACH IN ROOT ZONE OF MAIZE (95 ...

    African Journals Online (AJOL)

    DR. AMINU

    It is usual practice to use available soil water content as a criterion for deciding when irrigation is needed. Soil water content is determined by using soil measuring techniques (capacitance probe) that describe the depletion of available soil water see fig1 and 2. The irrigation scheduling is based on the water treatment (i.e. ...

  10. hardpan and maize root distribution under conservation and ...

    African Journals Online (AJOL)

    ACSS

    2016-08-23

    Aug 23, 2016 ... Norwegian University of Life Sciences, Department of Environmental Sciences, P. O. Box 5003,. 1430 Aas, Norway. Corresponding ... cultures dans l'agriculture à petite échelle conventionnelle en Afrique sub-saharienne. Cette étude remet en ...... Irrigation and Food, Lilongwe, and Food and. Agriculture ...

  11. Maize, tropical (Zea mays L.).

    Science.gov (United States)

    Assem, Shireen K

    2015-01-01

    Maize (Zea mays L.) is the third most important food crop globally after wheat and rice. In sub-Saharan Africa, tropical maize has traditionally been the main staple of the diet; 95 % of the maize grown is consumed directly as human food and as an important source of income for the resource-poor rural population. The biotechnological approach to engineer biotic and abiotic traits implies the availability of an efficient plant transformation method. The production of genetically transformed plants depends both on the ability to integrate foreign genes into target cells and the efficiency with which plants are regenerated. Maize transformation and regeneration through immature embryo culture is the most efficient system to regenerate normal transgenic plants. However, this system is highly genotype dependent. Genotypes adapted to tropic areas are difficult to regenerate. Therefore, transformation methods used with model genotypes adapted to temperate areas are not necessarily efficient with tropical lines. Agrobacterium-mediated transformation is the method of choice since it has been first achieved in 1996. In this report, we describe a transformation method used successfully with several tropical maize lines. All the steps of transformation and regeneration are described in details. This protocol can be used with a wide variety of tropical lines. However, some modifications may be needed with recalcitrant lines.

  12. 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...

  13. Arbuscular Mycorrhizal Fungi Negatively Affect Nitrogen Acquisition and Grain Yield of Maize in a N Deficient Soil.

    Science.gov (United States)

    Wang, Xin-Xin; Wang, Xiaojing; Sun, Yu; Cheng, Yang; Liu, Shitong; Chen, Xinping; Feng, Gu; Kuyper, Thomas W

    2018-01-01

    Arbuscular mycorrhizal fungi (AMF) play a crucial role in enhancing the acquisition of immobile nutrients, particularly phosphorus. However, because nitrogen (N) is more mobile in the soil solution and easier to access by plants roots, the role of AMF in enhancing N acquisition is regarded as less important for host plants. Because AMF have a substantial N demand, competition for N between AMF and plants particularly under low N condition is possible. Thus, it is necessary to know whether or not AMF affect N uptake of plants and thereby affect plant growth under field conditions. We conducted a 2-year field trial and pot experiments in a greenhouse by using benomyl to suppress colonization of maize roots by indigenous AMF at both low and high N application rates. Benomyl reduced mycorrhizal colonization of maize plants in all experiments. Benomyl-treated maize had a higher shoot N concentration and content and produced more grain under field conditions. Greenhouse pot experiments showed that benomyl also enhanced maize growth and N concentration and N content when the soil was not sterilized, but had no effect on maize biomass and N content when the soil was sterilized but a microbial wash added, providing evidence that increased plant performance is at least partly caused by direct effects of benomyl on AMF. We conclude that AMF can reduce N acquisition and thereby reduce grain yield of maize in N-limiting soils.

  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. The effect and fate of water-soluble carbon nanodots in maize (Zea mays L.).

    Science.gov (United States)

    Chen, Jing; Dou, Runzhi; Yang, Zhongzhou; Wang, Xiaoping; Mao, Chuanbin; Gao, Xiang; Wang, Li

    2016-08-01

    In this study, the toxicity of water-soluble carbon nanodots (C-dots) to maize (Zea mays L.) and their uptake and transport in plants were investigated. After exposed in sand matrix amended with 0-2000 mg/L C-dots for 4 weeks, we found that the phytotoxicity of C-dots was concentration-dependent. C-dots at 250 and 500 mg/L showed no toxicity to maize. However, 1000 and 2000 mg/L C-dots significantly reduced the fresh weight of root by 57% and 68%, and decreased the shoot fresh weight by 38% and 72%, respectively. Moreover, in maize roots, the exposure of C-dots at 2000 mg/L significantly increased the H2O2 content and lipid peroxidation (6.5 and 1.65 times higher, respectively), as well as, the antioxidant enzymes activities, up to 2, 1.5, 1.9 and 1.9 times higher for catalase, ascorbate peroxidase, guaiacol peroxidase and superoxide dismutase, respectively. On the other hand, C-dots were observed in detached root-cap cells, cortex and vascular bundle of roots and mesophyll cells of leaves through fluorescence microscopy analysis, suggesting that C-dots were absorbed and translocated systemically in maize. Remarkably, a certain amount of C-dots were excreted out from leaf blade. To our knowledge, this is the first study combined phenotypic observation with physiologic responses and bioaccumulation and translocation analysis of C-dots to investigate their effect and fate in maize.

  16. Overexpression of Thellungiella halophila H+-pyrophosphatase Gene Improves Low Phosphate Tolerance in Maize

    Science.gov (United States)

    Pei, Laming; Wang, Jiemin; Li, Kunpeng; Li, Yongjun; Li, Bei; Gao, Feng; Yang, Aifang

    2012-01-01

    Low phosphate availability is a major constraint on plant growth and agricultural productivity. Engineering a crop with enhanced low phosphate tolerance by transgenic technique could be one way of alleviating agricultural losses due to phosphate deficiency. In this study, we reported that transgenic maize plants that overexpressed the Thellungiella halophila vacuolar H+-pyrophosphatase gene (TsVP) were more tolerant to phosphate deficit stress than the wild type. Under phosphate sufficient conditions, transgenic plants showed more vigorous root growth than the wild type. When phosphate deficit stress was imposed, they also developed more robust root systems than the wild type, this advantage facilitated phosphate uptake, which meant that transgenic plants accumulated more phosphorus. So the growth and development in the transgenic maize plants were not damaged as much as in the wild type plants under phosphate limitation. Overexpression of TsVP increased the expression of genes involved in auxin transport, which indicated that the development of larger root systems in transgenic plants might be due in part to enhanced auxin transport which controls developmental events in plants. Moreover, transgenic plants showed less reproductive development retardation and a higher grain yield per plant than the wild type plants when grown in a low phosphate soil. The phenotypes of transgenic maize plants suggested that the overexpression of TsVP led to larger root systems that allowed transgenic maize plants to take up more phosphate, which led to less injury and better performance than the wild type under phosphate deficiency conditions. This study describes a feasible strategy for improving low phosphate tolerance in maize and reducing agricultural losses caused by phosphate deficit stress. PMID:22952696

  17. Maize Bioactive Peptides against Cancer

    Science.gov (United States)

    Díaz-Gómez, Jorge L.; Castorena-Torres, Fabiola; Preciado-Ortiz, Ricardo E.; García-Lara, Silverio

    2017-06-01

    Cancer is one of the main chronic degenerative diseases worldwide. In recent years, consumption of whole-grain cereals and their derived food products has been associated with reduction risks of various types of cancer. Cereals main biomolecules includes proteins, peptides, and amino acids present in different quantities within the grain. The nutraceutical properties associated with peptides exerts biological functions that promote health and prevent this disease. In this review, we report the current status and advances on maize peptides regarding bioactive properties that have been reported such as antioxidant, antihypertensive, hepatoprotective, and anti-tumour activities. We also highlighted its biological potential through which maize bioactive peptides exert anti-cancer activity. Finally, we analyse and emphasize the possible areas of application for maize peptides.

  18. Heavy Metal Residues in Soil and Accumulation in Maize at Long-Term Wastewater Irrigation Area in Tongliao, China

    Directory of Open Access Journals (Sweden)

    Yintao Lu

    2015-01-01

    Full Text Available Soil and plant samples were collected from Tongliao, China, during the maize growth cycle between May and October 2010. Heavy metals, such as Cr, Pb, Ni, and Zn, were analyzed. The concentrations of Cr, Pb, Ni, and Zn in the wastewater-irrigated area were higher than those in the topsoil from the groundwater-irrigated area. The concentrations of metals in the maize increased as follows: Pb < Ni < Zn < Cr. In addition, Cr, Pb, and Ni mainly accumulated in the maize roots, and Zn mainly accumulated in the maize fruit. The results of translocation factors (TF and bioconcentration factors (BCF of maize for heavy metals revealed that maize is an excluder plant and a potential accumulator plant and can serve as an ideal slope remediation plant. In addition, the increasing heavy metal contents in soils that have been polluted by wastewater irrigation must result in the accumulation of Cr, Pb, Ni, and Zn in maize. Thus, the pollution level can be decreased by harvesting and disposing of and recovering the plant material.

  19. Putting the Function in Maize Genomics

    Directory of Open Access Journals (Sweden)

    Stephen P. Moose

    2009-07-01

    Full Text Available The 51st Maize Genetics Conference was held March 12–15, 2009 at Pheasant Run Resort in St. Charles, Illinois. Nearly 500 attendees participated in a scientific program (available at covering a wide range of topics which integrate the rich biology of maize with recent discoveries in our understanding of the highly dynamic maize genome. Among the many research themes highlighted at the conference, the historical emphasis on studying the tremendous phenotypic diversity of maize now serves as the foundation for maize as a leading experimental system to characterize the mechanisms that generate variation in complex plant genomes and associate evolutionary change with phenotypes of interest.

  20. Dry Priming of Maize Seeds Reduces Aluminum Stress

    Science.gov (United States)

    Alcântara, Berenice Kussumoto; Machemer-Noonan, Katja; Silva Júnior, Francides Gomes; Azevedo, Ricardo Antunes

    2015-01-01

    Aluminum (Al) toxicity is directly related to acidic soils and substantially limits maize yield. Earlier studies using hormones and other substances to treat the seeds of various crops have been carried out with the aim of inducing tolerance to abiotic stress, especially chilling, drought and salinity. However, more studies regarding the effects of seed treatments on the induction of Al tolerance are necessary. In this study, two independent experiments were performed to determine the effect of ascorbic acid (AsA) seed treatment on the tolerance response of maize to acidic soil and Al stress. In the first experiment (greenhouse), the AsA seed treatment was tested in B73 (Al-sensitive genotype). This study demonstrates the potential of AsA for use as a pre-sowing seed treatment (seed priming) because this metabolite increased root and shoot growth under acidic and Al stress conditions. In the second test, the evidence from field experiments using an Al-sensitive genotype (Mo17) and an Al-tolerant genotype (DA) suggested that prior AsA seed treatment increased the growth of both genotypes. Enhanced productivity was observed for DA under Al stress after priming the seeds. Furthermore, the AsA treatment decreased the activity of oxidative stress-related enzymes in the DA genotype. In this study, remarkable effects using AsA seed treatment in maize were observed, demonstrating the potential future use of AsA in seed priming. PMID:26714286

  1. Growth, cadmium uptake and accumulation of maize (Zea mays L.) under the effects of arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Liu, Lingzhi; Gong, Zongqiang; Zhang, Yulong; Li, Peijun

    2014-12-01

    The effects of three arbuscular mycorrhizal fungi isolates on Cd uptake and accumulation by maize (Zea mays L.) were investigated in a planted pot experiment. Plants were inoculated with Glomus intraradices, Glomus constrictum and Glomus mosseae at three different Cd concentrations. The results showed that root colonization increased with Cd addition during a 6-week growth period, however, the fungal density on roots decreased after 9-week growth in the treatments with G. constrictum and G. mosseae isolates. The percentage of mycorrhizal colonization by the three arbuscular mycorrhizal fungi isolates ranged from 22.7 to 72.3%. Arbuscular mycorrhizal fungi inoculations decreased maize biomass especially during the first 6-week growth before Cd addition, and this inhibitory effect was less significant with Cd addition and growth time. Cd concentrations and uptake in maize plants increased with arbuscular mycorrhizal fungi colonization at low Cd concentration (0.02 mM): nonetheless, it decreased at high Cd concentration (0.20 mM) after 6-week growth period. Inoculation with G. constrictum isolates enhanced the root Cd concentrations and uptake, but G. mosseae isolates showed the opposite results at high Cd concentration level after 9 week growth period, as compared to non-mycorrhizal plants. In conclusion, maize plants inoculated with arbuscular mycorrhizal fungi were less sensitive to Cd stress than uninoculated plants. G. constrictum isolates enhanced Cd phytostabilization and G. mosseae isolates reduced Cd uptake in maize (Z. mays L.).

  2. Nanoscale Zinc Oxide Particles for Improving the Physiological and Sanitary Quality of a Mexican Landrace of Red Maize

    Directory of Open Access Journals (Sweden)

    Juan Estrada-Urbina

    2018-04-01

    Full Text Available In this research, quasi-spherical-shaped zinc oxide nanoparticles (ZnO NPs were synthesized by a simple cost-competitive aqueous precipitation method. The engineered NPs were characterized using several validation methodologies: UV–Vis spectroscopy, diffuse reflection UV–Vis, spectrofluorometry, transmission electron microscopy (TEM, nanoparticle tracking analysis (NTA, and Fourier transform infrared (FTIR spectroscopy with attenuated total reflection (ATR. A procedure was established to coat a landrace of red maize using gelatinized maize starch. Each maize seed was treated with 0.16 mg ZnO NPs (~7.7 × 109 particles. The standard germination (SG and accelerated aging (AA tests indicated that ZnO NP-treated maize seeds presented better physiological quality (higher percentage of normal seedlings and sanitary quality (lower percentage of seeds contaminated by microorganisms as compared to controls. The application of ZnO NPs also improved seedling vigor, correlated to shoot length, shoot diameter, root length, and number of secondary roots. Furthermore, shoots and roots of the ZnO NP-treated maize seeds showed a marked increment in the main active FTIR band areas, most notably for the vibrations associated with peptide-protein, lipid, lignin, polysaccharide, hemicellulose, cellulose, and carbohydrate. From these results, it is concluded that ZnO NPs have potential for applications in peasant agriculture to improve the quality of small-scale farmers’ seeds and, as a result, preserve germplasm resources.

  3. Effect of Different Arbuscular Mycorrhizal Fungi on Growth and Physiology of Maize at Ambient and Low Temperature Regimes

    Directory of Open Access Journals (Sweden)

    Xiaoying Chen

    2014-01-01

    Full Text Available The effect of four different arbuscular mycorrhizal fungi (AMF on the growth and lipid peroxidation, soluble sugar, proline contents, and antioxidant enzymes activities of Zea mays L. was studied in pot culture subjected to two temperature regimes. Maize plants were grown in pots filled with a mixture of sandy and black soil for 5 weeks, and then half of the plants were exposed to low temperature for 1 week while the rest of the plants were grown under ambient temperature and severed as control. Different AMF resulted in different root colonization and low temperature significantly decreased AM colonization. Low temperature remarkably decreased plant height and total dry weight but increased root dry weight and root-shoot ratio. The AM plants had higher proline content compared with the non-AM plants. The maize plants inoculated with Glomus etunicatum and G. intraradices had higher malondialdehyde and soluble sugar contents under low temperature condition. The activities of catalase (CAT and peroxidase of AM inoculated maize were higher than those of non-AM ones. Low temperature noticeably decreased the activities of CAT. The results suggest that low temperature adversely affects maize physiology and AM symbiosis can improve maize seedlings tolerance to low temperature stress.

  4. Global maize production, utilization, and consumption.

    Science.gov (United States)

    Ranum, Peter; Peña-Rosas, Juan Pablo; Garcia-Casal, Maria Nieves

    2014-04-01

    Maize (Zea mays), also called corn, is believed to have originated in central Mexico 7000 years ago from a wild grass, and Native Americans transformed maize into a better source of food. Maize contains approximately 72% starch, 10% protein, and 4% fat, supplying an energy density of 365 Kcal/100 g and is grown throughout the world, with the United States, China, and Brazil being the top three maize-producing countries in the world, producing approximately 563 of the 717 million metric tons/year. Maize can be processed into a variety of food and industrial products, including starch, sweeteners, oil, beverages, glue, industrial alcohol, and fuel ethanol. In the last 10 years, the use of maize for fuel production significantly increased, accounting for approximately 40% of the maize production in the United States. As the ethanol industry absorbs a larger share of the maize crop, higher prices for maize will intensify demand competition and could affect maize prices for animal and human consumption. Low production costs, along with the high consumption of maize flour and cornmeal, especially where micronutrient deficiencies are common public health problems, make this food staple an ideal food vehicle for fortification. © 2014 New York Academy of Sciences. The World Health Organization retains copyright and all other rights in the manuscript of this article as submitted for publication.

  5. A deeper look at the relationship between root carbon pools and the vertical distribution of the soil carbon pool

    Directory of Open Access Journals (Sweden)

    R. Dietzel

    2017-08-01

    Full Text Available Plant root material makes a substantial contribution to the soil organic carbon (C pool, but this contribution is disproportionate below 20 cm where 30 % of root mass and 50 % of soil organic C is found. Root carbon inputs changed drastically when native perennial plant systems were shifted to cultivated annual plant systems. We used the reconstruction of a native prairie and a continuous maize field to examine both the relationship between root carbon and soil carbon and the fundamental rooting system differences between the vegetation under which the soils developed versus the vegetation under which the soils continue to change. In all treatments we found that root C  :  N ratios increased with depth, and this plays a role in why an unexpectedly large proportion of soil organic C is found below 20 cm. Measured root C  :  N ratios and turnover times along with modeled root turnover dynamics showed that in the historical shift from prairie to maize, a large, structural-tissue-dominated root C pool with slow turnover concentrated at shallow depths was replaced by a small, nonstructural-tissue-dominated root C pool with fast turnover evenly distributed in the soil profile. These differences in rooting systems suggest that while prairie roots contribute more C to the soil than maize at shallow depths, maize may contribute more C to soil C stocks than prairies at deeper depths.

  6. Allelopathic potential of Jimsonweed (Datura stramonium L. on the early growth of maize (Zea mays L. and sunflower (Helianthus annuus L.

    Directory of Open Access Journals (Sweden)

    Zvonko Pacanoski

    2014-09-01

    Full Text Available Laboratory and glasshouse experiments were carried out to investigate the allelopathic potential of different plant parts of D. stramonium on maize and sunflower on early growth stages. The aqueous leachates of D. stramonium roots and shoot did not produc a significant effect on germination and shoot length of maize, but root length of maize was significantly reduced at the highest (1/1 D. stramonium roots leachate compared to control. From the other side, germination of sunflower was significantly reduced at the highest (1/1 D. stramonium shoot leachate concentration, but lower (1/5 and 1/2 D. stramonium roots leachate concentrations significantly increased root and shoot length of sunflower compared to control. In glasshouse experiment, no one treatment with different D. stramonium plant residues significantly affected density, height and fresh weight of maize plants compared to control. Contrary, D. stramonium mixtures with 1/1 root and shoot residues significantly reduced plants density and fresh weight of sunflower plants compared to control. Lower (1/2 and 1/5 mixtures of D. stramonium roots residues and mixture with 1/5 D. stramonium shoot residues significantly increased the height of the sunflower plants.

  7. Effect of Thorium on Growth and Uptake of Some Elements by Maize Plant

    International Nuclear Information System (INIS)

    Al-Shobaki, M.E.E.

    2012-01-01

    A pot experiment (sand culture) was carried out to investigate the effect of thorium on maize dry matter yield, contents and uptake of N,P ,K, Na and Fe and thorium accumulation in maize plant.The pots were contaminated by thorium as Thorium Nitrate(Th (NO 3 ) 4 ,H 2 O)at concentrations 0,5,10,11,12,13,14,15 and 50 ppm. Pots irrigated by 1/10 Hogland solution for 15 days, increased tol/4 Hogland solution after that.The results show that the dry matter (shoot, root and whole plant)decreased with increasing thorium concentration in soil up to 12 ppm and slightly increased with increasing Th to 13 ppm . The Nitrogen content and its uptake decreased with increasing thorium concentration in media growth up to 11 ppm .They were slightly increased at Th concentration between 11-14 ppm in maize shoot and root. The shoots always contained N-content and uptake more than that found in roots . P- uptake decreased in both shoots and roots with increasing in thorium concentration in media growth.

  8. Maize starch biphasic pasting curves

    CSIR Research Space (South Africa)

    Nelles, EM

    2000-05-01

    Full Text Available (150–500 rev/min). The second pasting peak is attributed to the formation of complexes between amylose and low levels of lipid present in maize starch. When lipid was partially removed by extraction with methanol-chloroform (1: 3 v/v), the second...

  9. Adição de ácido cítrico potencializa a ação de ácidos húmicos e altera o perfil protéico da membrana plasmática em raízes de milho Citric acid addition improve humic acids action and change proteins profile from plasma membrane of maize roots

    Directory of Open Access Journals (Sweden)

    Janaína Aparecida Hottz Rima

    2011-04-01

    ízes.The plant growth stimulation by humic acids (HA has been attributed to a hormone-like effect as promoting the root development and proliferation, resulting in a more efficient water and nutrient absorption. This research aims to investigate how the humic acids isolated from vermicompost (20mg L-1 can modify the root architecture and the plasma membrane (PM protein patterns in maize roots. It was also analyzed the effect of the citric acid (CA, an organic acid present in root exudates. The changes induced in the corn root system were estimated by measuring the taproot length, the amount of root mitotic sites and lateral roots, and the total root area. Plasma membrane vesicles were purified by cell fractionation and the protein patterns were analyzed by uni (1D and bidimensional (2D electrophoresis. The results show that the HA in solution with CA (0.005mM increases the lateral root growth promotion (126%, the root area (58%, and the number of lateral roots (55%. The activity of the plasma membrane H+ pump, analyzed as a marker of the induction of the acid growth mechanism, was also enhanced (374% by the humic solution supplemented with CA. Expression of several plasma membrane proteins was inhibited when plants were treated with HA and this effect was more pronounced upon CA supplementation. The obtained results corroborate the proposed mechanism for the HA bioactivity, by which under the action of root-exuded organic acids, such as CA, a disruption of the HA macrostructure is promoted releasing bioactive molecules presented in the humic aggregates, which becomes more accessible to the root cell receptors.

  10. Effects of application of groundnut biomass compost on uptake of phosphorus by maize grown on an Ultisol of South Sulawesi

    Directory of Open Access Journals (Sweden)

    Kasifah

    2014-07-01

    Full Text Available Low crop production is acid dryland area of South Sulawesi is due to low availability of P in the soils. One of alternatives that can be performed to overcome the problems of acid soils having high level of exchangeable Al, is through the addition of organic material. In the upland areas in South Sulawesi, crop rice, maize and groundnut crop residues are readily available, but the crop residues are generally only used as animal feed or even burned. This study was aimed to elucidate the effects of groundnut compost on P uptake by maize in Ultisol of Moncongloe, South Sulawesi. Eight kilograms of air dried soil was mixed with compost according to the following treatments; 0, 10, 15, 20, 25, 30, 35 and 40 t compost/ha. All pots received 200 kg/ha KCl and 300 kg Urea/ha as basal fertilizers. Two maize seeds were planted in each pot and thinned to one plant per pot after one week. At harvest maize shoot dry weight and maize root dry weight, length of maize cop, cob weight, cob diameter, weight grains per cob, P uptake by maize, P content in maize grain, soil available P were measured. Results of the study showed that groundnut compost has the ability to improve the availability of P in the soil and increase P uptake by maize grown on an Ultisol of South Sulawesi. Application of 25 t groundnut compost/ha was the optimal rate that can be used to increase P availability in an Ultisol of South Sulawesi.

  11. 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

  12. Arbuscular mycorrhizal fungi differ in their ability to regulate the expression of phosphate transportors in maize (Zea mays L.)

    Science.gov (United States)

    A greenhouse experiment was conducted to study the expression of two phosphate (P) transporter genes ZEAma:Pht1;3 (epidermal-expressed) and ZEAma:Pht1;6 (AM specific induced, and expressed around arbuscules) in maize root to colonization by different arbuscular mycorrhizal (AM) fungal inoculants. No...

  13. Root (Botany)

    Science.gov (United States)

    Robert R. Ziemer

    1981-01-01

    Plant roots can contribute significantly to the stability of steep slopes. They can anchor through the soil mass into fractures in bedrock, can cross zones of weakness to more stable soil, and can provide interlocking long fibrous binders within a weak soil mass. In deep soil, anchoring to bedrock becomes negligible, and lateral reinforcement predominates

  14. YIELDING AND CONTENT OF SELECTED MICROELEMENTS IN MAIZE FERTILIZED WITH VARIOUS ORGANIC MATERIALS

    Directory of Open Access Journals (Sweden)

    Jerzy Wieczorek

    2017-07-01

    On the basis of conducted research it was found that various fertilizer combinations applied in the experiment had a significant influence on the test plant yielding. All compared fertilizer variants allowed maize to produce statistically significantly higher yield in comparison with the yield harvested from the unfertilized soils. Fertilization with sewage sludge I supplemented with mineral treatment and application of solely mineral salts proved the most beneficial for the maize yield. Applied fertilizer combinations affected the content of microelements. The highest concentrations of nickel in maize green mass were assessed in plant samples from the unfertilized object, whereas zinc and copper from mineral fertilization variant. Except of zinc, introducing additional metal doses did not influence their increased content in plant organs. Soil enrichment with zinc contained in sewage sludge I and II (respectively 77.4 mg and 49.9 mg ∙ pot-1 contributed to its elevated concentration in maize roots but at the same time this metal content statistically significantly decreased in maize shoots in comparison with the amounts determined in plants fertilized with mineral materials.

  15. Seed Priming with Melatonin Effects on Seed Germination and Seedling Growth in Maize under Salinity Stress

    International Nuclear Information System (INIS)

    Jiang, X.; Li, H.; Song, X.

    2016-01-01

    The effects on seed germination and seedling growth in maize under salinity stress by seed priming with melatonin were investigated. Seeds of maize cultivar Nonghua101 were soaked in 0.4, 0.8 and 1.6 mM aerated solution of melatonin for 24 h, and primed seeds were germinated under the condition of 150 mM NaCl with paper media. The results showed seed priming with 0.8 mM melatonin was the best performance of all the treatments to seed germination and seedling growth in maize under salinity stress. Then primed with 0.8 mM melatonin or water for 24 h and unprimed seeds were germination under the condition of 150 mM NaCl with sand media. The results showed seed priming with 0.8 mM melatonin significantly improved germination energy, germination percentage, seedling vigor index, shoot and root lengths, seedling fresh and dry weights, K/sup +/ content, relative water content, proline and total phenolic contents, superoxide dismutase, catalase and phenylalanin ammonia lyase activities; and significantly decreased mean emergence time, Na/sup +/ content, electrolyte leakage and malondialdehyde content compared with untreated seeds under salinity stress. These results suggest that seed priming with melatonin alleviates the salinity damage to maize and seed priming with melatonin may be an important alternative approach to decrease the impact of salinity stress in maize. (author)

  16. Sorghum as an alternative of cultivation to maize; Sorghumhirse als Anbaualternative zum Mais

    Energy Technology Data Exchange (ETDEWEB)

    Jaekel, Kerstin; Theiss, Markus; Poetzschke, Karen [Saechsisches Landesamt fuer Umwelt, Landwirtschaft und Geologie (LfULG), Dresden (Germany)] [and others

    2013-10-01

    Due to their high dry matter yield potential Sorghum bicolor and Sorghum bicolor x sudanense are well fitted as feedstock for biogas production. Similar to maize, both species show a high efficiency in their use of water (C4-plants). However, Sorghum has a higher drought tolerance in comparison with maize but is more sensitive to low temperatures. Hence a cultivation of Sorghum is recommendable especially in dry and relatively warm regions, including recultivated areas and even on loess soil, provided that the required temperatures are given. Due to the fact that Sorghum is not affected by the corn root worm, it also could gain relevance in regions were the cultivation of maize is restricted. Furthermore, Sorghum is usable as a catch crop as well as a main crop because of its variable sowing time. Catch crop cultivation, however, yields a significantly lower amount of dry matter and -quality which is a result of its shorter vegetation period. Owing to its higher crude fiber concentration Sorghum achieves a lower theoretically attainable specific methane yield (Weissbach) than maize. Thus only on rare occasions Sorghum does achieve methane yields per hectare that are comparable to maize. Eventually, the competitiveness of Sorghum greatly depends on provision of enhanced cultivars achieved through genetic improvement. (orig.)

  17. 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

  18. Dissolution of different zinc salts and zn uptake by Sedum alfredii and maize in mono- and co-cropping under hydroponic culture.

    Science.gov (United States)

    Jiang, Cheng'ai; Wu, Qitang; Zeng, Shucai; Chen, Xian; Wei, Zebin; Long, Xinxian

    2013-09-01

    Previous soil pot and field experiments demonstrated that co-cropping the hyperaccumulator Sedum alfredii with maize increased Zn phytoextraction by S. alfredii and decreased Zn uptake by maize shoots. This hydroponic experiment was conducted to investigate whether the facilitation of Zn phytoextraction by S. alfredii resulted from improved dissolution in this co-cropping system and its relation to root exudates. S. alfredii and maize were mono- and co-cropped (without a root barrier) in nutrient solution spiked with four Zn compounds, ZnS, ZnO, Zn3(PO4)2 and 5ZnO x 2CO3-4H2O (represented as ZnCO3) at 1000 mg/L Zn for 15 days without renewal of nutrient solution after pre-culture. The root exudates were collected under incomplete sterilization and analyzed. The results indicated that the difference in Zn salts had a greater influence on the Zn concentration in maize than for S. alfredii, varying from 210-2603 mg/kg for maize shoots and 6445-12476 mg/kg for S. alfredii in the same order: ZnCO3 > ZnO > Zn3(PO4)2 > ZnS. For the four kinds of Zn sources in this experiment, co-cropping with maize did not improve Zn phytoextraction by S. alfredii. In most cases, compared to co-cropped and mono-cropped maize, mono-cropped S. alfredii resulted in the highest Zn2+ concentration in the remaining nutrient solution, and also had a higher total concentration of low molecular weight organic acids (LMWOA) and lower pH of root exudation. Root exudates did partly influence Zn hyperaccumulation in S. alfredii.

  19. 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)

  20. Extraction and characterization of natural cellulose fibers from maize tassel

    CSIR Research Space (South Africa)

    Maepa, CE

    2015-04-01

    Full Text Available This article reports on the extraction and characterization of novel natural cellulose fibers obtained from the maize (tassel) plant. Cellulose was extracted from the agricultural residue (waste biomaterial) of maize tassel. The maize tassel fibers...

  1. Screening for salt tolerance in maize (zea mays l.) hybrids at an early seedling stage

    International Nuclear Information System (INIS)

    Akram, M.; Mohsan; Ashraf, M.Y.; Ahmad, R.; Waraich, E.A.

    2010-01-01

    An efficient and simple mass screening technique for selection of maize hybrids for salt tolerance has been developed. Genetic variation for salt tolerance was assessed in hybrid maize (Zea mays L.) using solution-culture technique. The study was conducted in solution culture exposed to four salinity levels (control, 40, 80 and 120 mM NaCl). Seven days old maize seedlings were transplanted in themopol sheet in iron tubs containing one half strength Hoagland nutrient solutions and salinized with common salt (NaCl). The experiment was conducted in the rain protected wire house of Stress Physiology Laboratory of NIAB, Faisalabad, Pakistan. Ten maize hybrids were used for screening against four salinity levels. Seedling of each hybrid was compared for their growth under saline conditions as a percentage of the control values. Considerable variations were observed in the root, shoot length and biomass of different hybrids at different salinity levels. The leaf sample analyzed for inorganic osmolytes (sodium, potassium and calcium) showed that hybrid Pioneer 32B33 and Pioneer 30Y87 have high biomass, root shoot fresh weight and high ratio and showed best salt tolerance performance at all salinity levels on overall basis. (author)

  2. Effect of crude oil and palm bunch ash on maize growth

    Institute of Scientific and Technical Information of China (English)

    Emmanue Ogboma Dania; Temitayo Fayehun; Osemhengbe Ruth Akhabue

    2016-01-01

    Objective:To investigate the effect of different crude oil fractions (whole crude and water soluble fraction) at 2% contamination (98% distilled water) and the effect of 2 g of palm bunch ash (PBA) on the phytotoxicity of crude oil fraction on growth parameters such as percentage of seedling emergence, plant height, number of leaves, length of root, length of radical and leaf area in maize (Zea mays). Methods: A total of 180 bags containing 500 g of loamy soil each were used for this study, of which 30 bags containing loamy soil each served as control, 60 bags of soil were added each 2% crude oil fraction and 60 bags of soil were added each 2% crude oil fraction and 2 gPBA each, while 30 bags of soil contained each 2 g ofPBA only. The maize grown on the soil was harvested after 7, 14 and 21 days of seedling emergence and assessed for growth parameters. Results: The growth parameters (plant height, length of root, length of radicle, number of leaves, and leaf area) in maize were significantly reduced in the crude oil fraction treatment (P≤0.05). The treatment containingPBA was found to have significant improvement compared to the crude oil fraction contaminated treatment. Conclusions: The study has revealed the deleterious effect of crude oil at 2% on maize and its effect was ameliorated usingPBA.

  3. Enhanced water stress tolerance of transgenic maize plants over-expressing LEA Rab28 gene.

    Science.gov (United States)

    Amara, Imen; Capellades, Montserrat; Ludevid, M Dolors; Pagès, Montserrat; Goday, Adela

    2013-06-15

    Late Embryogenesis Abundant (LEA) proteins participate in plant stress responses and contribute to the acquisition of desiccation tolerance. In this report Rab28 LEA gene has been over-expressed in maize plants under a constitutive maize promoter. The expression of Rab28 transcripts led to the accumulation and stability of Rab28 protein in the transgenic plants. Native Rab28 protein is localized to nucleoli in wild type maize embryo cells; here we find by whole-mount immunocytochemistry that in root cells of Rab28 transgenic and wild-type plants the protein is also associated to nucleolar structures. Transgenic plants were tested for stress tolerance and resulted in sustained growth under polyethyleneglycol (PEG)-mediated dehydration compared to wild-type controls. Under osmotic stress transgenic seedlings showed increased leaf and root areas, higher relative water content (RWC), reduced chlorophyll loss and lower Malondialdehyde (MDA) production in relation to wild-type plants. Moreover, transgenic seeds exhibited higher germination rates than wild-type seeds under water deficit. Overall, our results highlight the presence of transgenic Rab28 protein in nucleolar structures and point to the potential of group 5 LEA Rab28 gene as candidate to enhance stress tolerance in maize plants. Copyright © 2013 Elsevier GmbH. All rights reserved.

  4. Aflatoxin levels in maize and maize products during the 2004 food ...

    African Journals Online (AJOL)

    Aflatoxin levels in maize and maize products during the 2004 food poisoning ... district were received at the National Public Health Laboratory Services (NPHLS). On analysis, they were found to be highly contaminated with aflatoxin B1.

  5. Ethylene Contributes to maize insect resistance1-Mediated Maize Defense against the Phloem Sap-Sucking Corn Leaf Aphid1[OPEN

    Science.gov (United States)

    Louis, Joe; Basu, Saumik; Varsani, Suresh; Castano-Duque, Lina; Jiang, Victoria; Williams, W. Paul; Felton, Gary W.; Luthe, Dawn S.

    2015-01-01

    Signaling networks among multiple phytohormones fine-tune plant defense responses to insect herbivore attack. Previously, it was reported that the synergistic combination of ethylene (ET) and jasmonic acid (JA) was required for accumulation of the maize insect resistance1 (mir1) gene product, a cysteine (Cys) proteinase that is a key defensive protein against chewing insect pests in maize (Zea mays). However, this study suggests that mir1-mediated resistance to corn leaf aphid (CLA; Rhopalosiphum maidis), a phloem sap-sucking insect pest, is independent of JA but regulated by the ET-signaling pathway. Feeding by CLA triggers the rapid accumulation of mir1 transcripts in the resistant maize genotype, Mp708. Furthermore, Mp708 provided elevated levels of antibiosis (limits aphid population)- and antixenosis (deters aphid settling)-mediated resistance to CLA compared with B73 and Tx601 maize susceptible inbred lines. Synthetic diet aphid feeding trial bioassays with recombinant Mir1-Cys Protease demonstrates that Mir1-Cys Protease provides direct toxicity to CLA. Furthermore, foliar feeding by CLA rapidly sends defensive signal(s) to the roots that trigger belowground accumulation of the mir1, signifying a potential role of long-distance signaling in maize defense against the phloem-feeding insects. Collectively, our data indicate that ET-regulated mir1 transcript accumulation, uncoupled from JA, contributed to heightened resistance to CLA in maize. In addition, our results underscore the significance of ET acting as a central node in regulating mir1 expression to different feeding guilds of insect herbivores. PMID:26253737

  6. Assessment of maize stem borer damage on hybrid maize varieties in Chitwan, Nepal

    OpenAIRE

    Buddhi Bahadur Achhami; Santa Bahadur BK; Ghana Shyam Bhandari

    2015-01-01

    Maize is the second most important cereal crop in Nepal. However, national figure of grain production still remains below than the world's average grain production per unit area. Thus, this experiment was designed to determine the suitable time of maize planting, and to assess the peak period of one of the major insects, maize stem borer, in Chitwan condition. The results showed that plant damage percentage as per the maize planting month varies significantly, and the average plant damage per...

  7. Root Differentiation of Agricultural Plant Cultivars and Proveniences Using FTIR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Nicole Legner

    2018-06-01

    Full Text Available The differentiation of roots of agricultural species is desired for a deeper understanding of the belowground root interaction which helps to understand the complex interaction in intercropping and crop-weed systems. The roots can be reliably differentiated via Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR. In two replicated greenhouse experiments, six pea cultivars, five oat cultivars as well as seven maize cultivars and five barnyard grass proveniences (n = 10 plants/cultivar or provenience were grown under controlled conditions. One root of each plant was harvested and five different root segments of each root were separated, dried and measured with FTIR-ATR spectroscopy. The results showed that, firstly, the root spectra of single pea and single oat cultivars as well as single maize and single barnyard grass cultivars/proveniences separated species-specific in cluster analyses. In the majority of cases the species separation was correct, but in a few cases, the spectra of the root tips had to be omitted to ensure the precise separation between the species. Therefore, species differentiation is possible regardless of the cultivar or provenience. Consequently, all tested cultivars of pea and oat spectra were analyzed together and separated within a cluster analysis according to their affiliated species. The same result was found in a cluster analysis with maize and barnyard grass spectra. Secondly, a cluster analysis with all species (pea, oat, maize and barnyard grass was performed. The species split up species-specific and formed a dicotyledonous pea cluster and a monocotyledonous cluster subdivided in oat, maize and barnyard grass subclusters. Thirdly, cultivar or provenience differentiations within one species were possible in one of the two replicated experiments. But these separations were less resilient.

  8. Effect of various tillage practices on soil properties and maize growth

    International Nuclear Information System (INIS)

    Leghari, N.

    2016-01-01

    Appropriate tillage practices are vital for good tilth that is pre-requisite for aggregate formation, soil aeration, better root development and plant growth. A field experiment of maize was carried out at the experimental site of Sindh Agriculture University Tandojam during two consecutive growing seasons 2009 and 2010. A randomized complete block design with three treatment conventional tillage (CT), reduced tillage (RT) and no tillage (NT) was used in the study. Significant differences between tillage treatments were observed in the soil properties, growth and root development of plants. The NT treatment retained higher soil water contents (15.8 and 16.0%) measured at 0-20 cm depth during 2009 and 2010, respectively. Likewise, the soil bulk density (1.4 and 1.4 cm-3) was higher at this depth consequently; it resulted in greater soil strength (81 N m-2 and 79 N m-2) during 2009 and 2010, respectively. The negative and significant correlations were recorded between root dry weight and soil strengths. On the other hand, positive and significant relationship of root dry weight with mean total dry matter production and LAI was observed. Moreover, the root development related observations were significantly enhanced under CT as compared to RT and NT treatments. The results indicate that conventional tillage improve maize growth and root development by improving soil properties. (author)

  9. Differential effects of fine root morphology on water dynamics in the root-soil interface

    Science.gov (United States)

    DeCarlo, K. F.; Bilheux, H.; Warren, J.

    2017-12-01

    Soil water uptake form plants, particularly in the rhizosphere, is a poorly understood question in the plant and soil sciences. Our study analyzed the role of belowground plant morphology on soil structural and water dynamics of 5 different plant species (juniper, grape, maize, poplar, maple), grown in sandy soils. Of these, the poplar system was extended to capture drying dynamics. Neutron radiography was used to characterize in-situ dynamics of the soil-water-plant system. A joint map of root morphology and soil moisture was created for the plant systems using digital image processing, where soil pixels were connected to associated root structures via minimum distance transforms. Results show interspecies emergent behavior - a sigmoidal relationship was observed between root diameter and bulk/rhizosphere soil water content difference. Extending this as a proxy for extent of rhizosphere development with root age, we observed a logistic growth pattern for the rhizosphere: minimal development in the early stages is superceded by rapid onset of rhizosphere formation, which then stabilizes/decays with the likely root suberization. Dynamics analysis of water content differences between the root/rhizosphere, and rhizosphere/bulk soil interface highlight the persistently higher water content in the root at all water content and root size ranges. At the rhizosphere/bulk soil interface, we observe a shift in soil water dynamics by root size: in super fine roots, we observe that water content is primarily lower in the rhizosphere under wetter conditions, which then gradually increases to a relatively higher water content under drier conditions. This shifts to a persistently higher rhizosphere water content relative to bulk soil in both wet/dry conditions with increased root size, suggesting that, by size, the finest root structures may contribute the most to total soil water uptake in plants.

  10. 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

  11. 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.

  12. Phytotoxic Effects of Lanthanum Oxide Nanoparticles on Maize (Zea mays L.)

    Science.gov (United States)

    Liu, Yinglin; Xu, Lina; Dai, Yanhui

    2018-02-01

    The use of lanthanum oxide nanoparticles (La2O3 NPs) in life products have increased dramatically in the past decades, which are inevitable released into natural environment. In this study, we determined the phytotoxicity of La2O3 NPs to maize (Zea mays L.) grown in one-fourth strength Hoagland solution. After being exposed for two weeks, the biomass, roots length and the relative chlorophyll content were measured. La2O3 NPs had phytotoxicity to maize at 5 mg/L. La2O3 NPs decreased shoot biomass (≥10 mg/L), the root biomass and length (≥5 mg/L). Moreover, La2O3 NPs had adverse effects on the chlorophyll content (≥10 mg/L). The decreased chlorophyll content may reduce net photosynthetic rate. This research offers vital information about the phytotoxicity of La2O3 NPs.

  13. Effect of soil herbicides on the antioxidant system of maize vegetative organs during ontogenesis

    Directory of Open Access Journals (Sweden)

    I.P. Grigoryuk

    2016-06-01

    Full Text Available The impact of soil herbicides Harnes, Frontier and Merlin on the activity of enzymes superoxid dismutase (SOD, EC 1.15.1.1, catalase (CAT, EC 1.11.1.6, and benzidine peroxidase (POD, EC 1.11.1.7 in maize (Zea mays L.; cultivar Kadr 267 MV roots and leaves was studied in the field experiment. It was established that the adaptation of maize plants to the herbicides treatment was accompanied by significant activation of antioxidant enzymes both in roots (39%, 57%, and 67% above control level and leaves (50%, 64%, and 77% above control, respectively during different vegetation stages (shoots emergence; 3–5 leaves phase; florescence. The herbicides-induced changes of enzymes activity high correlated with ontogenetic dynamics of control plants activity: r = 0.98 for SOD; r = 0.96 for POD; r = 0.98 for CAT.

  14. "Achieving Mexico’s Maize Potential"

    OpenAIRE

    Antonio Turrent Fernández; Timothy A. Wise; Elise Garvey

    2012-01-01

    Rising agricultural prices, combined with growing import dependence, have driven Mexico’s food import bill over $20 billion per year and increased its agricultural trade deficit. Mexico imports one-third of its maize, overwhelmingly from the United States, but three million producers grow most of the country’s white maize, which is used primarily for tortillas and many other pluricultural products for human consumption. Yield gaps are large among the country’s small to medium-scale maize farm...

  15. Effects of INH, DNP, 2, 4-D and CMU on the sugar content of the barley and maize leaves; Efecto de cuatro inhibidores metabolicos (INH, DNP, 2, 3-D y CMU) sobre el contenido en azucares de hohas de cebada (Hordeum vulgare L.) y Maiz (Zea mais L.)

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, J; Sancho, P

    1979-07-01

    1 ppm of the chemicals in nutritive solution was absorbed by barley and maize roots during 24 and 48 hours in dark or light conditioners in order to determine the best conditions. for the obtention of labelled sugars with high specific activity. Results show that the highest specific activity was obtained In maize plants treated with DNP for 24 hours in dark conditions. (Author) 51 refs.

  16. Disseminating genetically modified (GM) maize technology to ...

    African Journals Online (AJOL)

    Disseminating genetically modified (GM) maize technology to smallholder farmers in the Eastern Cape province of South Africa: extension personnel's awareness of stewardship requirements and dissemination practices.

  17. Influence of Maize Rotations on the Yield of Soybean Grown in Meloidogyne incognita Infested Soil

    OpenAIRE

    Kinloch, Robert A.

    1983-01-01

    A replicated field study was conducted from 1972 to 1980 involving soybeans grown in 2-, 3-, and 4-year rotations with maize in soil infested with Meloidogyne incognita. Monocultured soybeans were maintained as controls. Cropping regimes involved root-knot nematode susceptible and resistant soybean cultivars and soybeans treated and not treated with nematicides. Yields of susceptible cultivars declined with reduced length of rotation. Nematicide treatment significantly increased yields of sus...

  18. Stable isotopes estimate the dependence of the parasitic angiosperm striga hermonthica on its maize host

    International Nuclear Information System (INIS)

    Aflakpui, G.K.S.

    2004-01-01

    The dependence of the root hemi-parasitic angiosperm striga hermonthica on its host for carbon (C) and nitrogen (N) was estimated by labeling the leaves of maize (grown in sand culture at three rates of nitrogen) with 13 C and 15 N. The Striga x N interaction on the responses measured was not significant. The dependence of the parasite on host nitrogen varied from 75 to 83 percent in the leaf, and from 70 to 80 percent in the stem compared with a total dependence of between 74 and 82 per cent. The dependence of the parasite on its host for nitrogen was not affected by the rate of nitrogen fertilizer applied. The heterotrophic carbon derived by S. hermonthica from its maize host varied from 20 to 32 per cent in the leaf, 23 to 41 per cent in the stem, with a total dependence of 22 to 36 per cent. The heterotrophic carbon in the leaf increased as the rate of nitrogen fertilizer applied increased (P<0.05). The total dependence of the parasite on the host for carbon also increased (P<0.05). The total dependence of the parasite on the host for carbon also increased as the rate of nitrogen fertilizer applied increased (P<0.01). The presence of S. hermonthica reduced the shoot biomass of its maize host by about 40 percent (P<0.001), whilst the root biomass was unaffected. Infected plants also partitioned about 41 percent of their total biomass compared with 27 per cent for the uninfected (P<0.001). The application if nitrogen increased the shoot and root biomass (P<0.001) but did not affect the proportion of the total biomass partitioned to the root. The results show that (i) the dependence of striga on its maize host of C and N can be estimated with stable isotopes of C and N and (ii) Striga derives more nitrogen than carbon from the host. (author)

  19. Nitrogen transporter and assimilation genes exhibit developmental stage-selective expression in maize (Zea mays L.) associated with distinct cis-acting promoter motifs.

    Science.gov (United States)

    Liseron-Monfils, Christophe; Bi, Yong-Mei; Downs, Gregory S; Wu, Wenqing; Signorelli, Tara; Lu, Guangwen; Chen, Xi; Bondo, Eddie; Zhu, Tong; Lukens, Lewis N; Colasanti, Joseph; Rothstein, Steven J; Raizada, Manish N

    2013-10-01

    Nitrogen is considered the most limiting nutrient for maize (Zea mays L.), but there is limited understanding of the regulation of nitrogen-related genes during maize development. An Affymetrix 82K maize array was used to analyze the expression of ≤ 46 unique nitrogen uptake and assimilation probes in 50 maize tissues from seedling emergence to 31 d after pollination. Four nitrogen-related expression clusters were identified in roots and shoots corresponding to, or overlapping, juvenile, adult, and reproductive phases of development. Quantitative real time PCR data was consistent with the existence of these distinct expression clusters. Promoters corresponding to each cluster were screened for over-represented cis-acting elements. The 8-bp distal motif of the Arabidopsis 43-bp nitrogen response element (NRE) was over-represented in nitrogen-related maize gene promoters. This conserved motif, referred to here as NRE43-d8, was previously shown to be critical for nitrate-activated transcription of nitrate reductase (NIA1) and nitrite reductase (NIR1) by the NIN-LIKE PROTEIN 6 (NLP6) in Arabidopsis. Here, NRE43-d8 was over-represented in the promoters of maize nitrate and ammonium transporter genes, specifically those that showed peak expression during early-stage vegetative development. This result predicts an expansion of the NRE-NLP6 regulon and suggests that it may have a developmental component in maize. We also report leaf expression of putative orthologs of nitrite transporters (NiTR1), a transporter not previously reported in maize. We conclude by discussing how each of the four transcriptional modules may be responsible for the different nitrogen uptake and assimilation requirements of leaves and roots at different stages of maize development.

  20. RootAnalyzer: A Cross-Section Image Analysis Tool for Automated Characterization of Root Cells and Tissues.

    Directory of Open Access Journals (Sweden)

    Joshua Chopin

    Full Text Available The morphology of plant root anatomical features is a key factor in effective water and nutrient uptake. Existing techniques for phenotyping root anatomical traits are often based on manual or semi-automatic segmentation and annotation of microscopic images of root cross sections. In this article, we propose a fully automated tool, hereinafter referred to as RootAnalyzer, for efficiently extracting and analyzing anatomical traits from root-cross section images. Using a range of image processing techniques such as local thresholding and nearest neighbor identification, RootAnalyzer segments the plant root from the image's background, classifies and characterizes the cortex, stele, endodermis and epidermis, and subsequently produces statistics about the morphological properties of the root cells and tissues. We use RootAnalyzer to analyze 15 images of wheat plants and one maize plant image and evaluate its performance against manually-obtained ground truth data. The comparison shows that RootAnalyzer can fully characterize most root tissue regions with over 90% accuracy.

  1. Introgression of genetic material from Zea mays ssp. Mexicana into cultivated maize was facilitated by tissue culture

    International Nuclear Information System (INIS)

    Wang, L.; Gu, X.; Qu, M.; Luan, J.; Zhang, J.

    2012-01-01

    Zea mays ssp. mexicana, a wild relative of cultivated maize (Z. mays ssp. mays), is a useful gene resource for maize breeding. In this study, two populations were generated by conventional breeding scheme (population I) or tissue culture regime (population II), respectively, to introgress genetic material of Z. mays ssp. mexicana into maize. Karyotype analysis showed that the arm ratios of 10 pairs of chromosomes in parent maize Ye515 and derivative lines from 2 different populations with 26% and 38% chromosome variation frequencies, respectively. Alien chromatin was detected in the root tip cells of progeny plants through genomic in situ hybridization (GISH). There were 3.3 chromosomes carrying alien chromatin on average in population I and 6.5 in population II. The hybridization signals were located mainly at the terminal or sub terminal regions of the chromosomes and the sizes were notably variant among lines. Based on those results, it is concluded that the introgression of genetic material from Z. mays ssp. mexicana into cultivated maize was facilitated by tissue culture, and subsequently some excellent materials for maize breeding were created. (author)

  2. Maize germplasm of eastern Croatia with native resistance to western corn rootworm (Diabrotica virgifera virgifera LeConte

    Directory of Open Access Journals (Sweden)

    Brkić Andrija

    2017-01-01

    Full Text Available The western corn rootworm (Diabrotica virgifera virgifera LeConte; WCR is a serious maize pest in Croatia. The species was first registered in Europe in the early 1990s and since then became one of the most dangerous maize pests, especially in parts of Central and Southeast Europe. Larvae that feed on the maize roots cause the most serious damages in maize fields. Management of this pest is difficult and expensive, with possible serious impact on the environment. Native (or host-plant resistance of maize against WCR could provide new economically and ecologically sustainable options in WCR management. Main goal of this study was to assess the variability of maize germplasm, correlations among resistance traits, and detect potential sources of resistance that could be used in breeding programs in order to develop hybrids with higher level of resistance against WCR. To our knowledge, the first native resistant hybrid is yet to be registered. Results showed great variability of estimated germplasm. Effect of the genotype was significant in all environments, as well as many interactions between genotype and the environment. Significant interactions emphasize the importance of the environment in WCR native resistance research. Significant positive correlations among all traits were detected. Several inbred lines were selected as a potentially useful germplasm for resistance breeding programs.

  3. Number, position, diameter and initial direction of growth of primary roots in Musa.

    Science.gov (United States)

    Lecompte, Francois; Vaucelle, Aurelien; Pages, Loic; Ozier-Lafontaine, Harry

    2002-07-01

    To understand soil colonization by a root system, information is needed on the architecture of the root system. In monocotyledons, soil exploration is mainly due to the growth of adventitious primary roots. Primary root emergence in banana was quantified in relation to shoot and corm development. Root emergence kinetics were closely related to the development of aerial organs. Root position at emergence on the corm followed an asymptotic function of corm dry weight, so that the age of each root at a given time could be deduced from its position. Root diameter at emergence was related to the position of the roots on the corm, with younger roots being thicker than older ones. However, root diameters were not constant along a given root, but instead decreased with the distance to the base; roots appear to be conical in their basal and apical parts. Root growth directions at emergence were variable, but a high proportion of the primary roots emerged with a low angle to the horizontal. Further research is needed to evaluate whether these initial trajectories are conserved during root development. Results presented in this study are in good agreement with those reported for other monocotyledons such as maize and rice. They give quantitative information that will facilitate the development of models of root system architecture in banana.

  4. [Effects of soil pH on the competitive uptake of amino acids by maize and microorganisms].

    Science.gov (United States)

    Ma, Qing Xu; Wang, Jun; Cao, Xiao Chuang; Sun, Yan; Sun, Tao; Wu, Liang Huan

    2017-07-18

    Organic nitrogen can play an important role in plant growth, and soil pH changed greatly due to the over-use of chemical fertilizers, but the effects of soil pH on the competitive uptake of amino acids by plants and rhizosphere microorganisms are lack of detailed research. To study the effects of soil pH on the uptake of amino acids by maize and soil microorganisms, two soils from Hangzhou and Tieling were selected, and the soil pH was changed by the electrokinesis, then the 15 N-labeled glycine was injected to the centrifuge tube with a short-term uptake of 4 h. Soil pH had a significant effect on the shoot and root biomass, and the optimal pH for maize shoot growth was 6.48 for Hangzhou red soil, while it was 7.65 for Tieling brown soil. For Hangzhou soil, the 15 N abundance of maize shoots under pH=6.48 was significantly higher than under other treatments, and the uptake amount of 15 N-glycine was also much higher. However, the 15 N abundance of maize shoots and roots under pH=7.65 Tieling soil was significantly lower than it under pH=5.78, but the uptake amount of 15 N-glycine under pH=7.65 was much higher. The microbial biomass C was much higher in pH=6.48 Hangzhou soil, while it was much lower in pH=7.65 Tieling soil. According to the results of root uptake, root to shoot transportation, and the competition with microorganisms, we suggested that although facing the fierce competition with microorganisms, the maize grown in pH=6.48 Hangzhou soil increased the uptake of glycine by increasing its root uptake and root to shoot transportation. While in pH=7.65 Tieling soil, the activity of microorganisms was decreased, which decreased the competition with maize for glycine, and increased the uptake of glycine by maize.

  5. The iojap gene in maize

    Energy Technology Data Exchange (ETDEWEB)

    Martienssen, Robert

    2001-12-01

    The classical maize mutant iojap (Iodent japonica) has variegated green and white leaves. Green sectors have cells with normal chloroplasts whereas white sectors have cells where plastids fail to differentiate. These mutant plastids, when transmitted through the female gametophyte, do not recover in the presence of wild type Iojap. We cloned the Ij locus, and we have investigated the mechanism of epigenetic inheritance and phenotypic expression. More recently, a modifier of this type of variegation, ''Inhibitor of striate'', has also been cloned. Both the iojap and inhibitor of striate proteins have homologs in bacteria and are members of ancient conserved families found in multiple species. These tools can be used to address fundamental questions of inheritance and variegation associated with this classical conundrum of maize genetics. Since the work of Rhoades there has been considerable speculation concerning the nature of the Iojap gene product, the origin of leaf variegation and the mechanism behind the material inheritance of defective plastids. This has made Iojap a textbook paradigm for cytoplasmic inheritance and nuclear-organellar interaction for almost 50 years. Cloning of the Iojap gene in maize, and homologs in other plants and bacteria, provides a new means to address the origin of heteroplastidity, variegation and cytoplasmic inheritance in higher plants.

  6. Citric acid mediated phyto extraction of cadmium by maize (zea mays l.)

    International Nuclear Information System (INIS)

    Anwar, S.; Hussain, M.

    2012-01-01

    The aim of the investigation was to determine the potential of citric acid for accumulation and translocation of cadmium and their effect on maize growth. The plants were grown in small plastic glasses and treated with 300 mg kg/sup -1/ CdCl/sub 2/ and 0, 0.25, 0.5, 1 and 2 g kg/sup -1/ of citric acid. After 10 days, the plants were harvested, dried and root and shoot biomass weighed. To study the efficiency of maize to bioaccumulate metal, uptake of cadmium was studied in the root and shoot. The results showed that heavy metal accumulated more in roots than the shoots and application of citric acid depressed Cd uptake at all concentrations. Percent decrease in Cd uptake was 58, 35, 26, 25 and 63, 46, 44, 42 by Sahiwal-2002 and Pak-affgoee, respectively at 0.25, 0.5, 1 and 2 g kg/sup -1/ of citric acid application. Maize proved to be an effective accumulator for cadmium, however, neither concentration of citric acid showed advantages for phytoextraction of cadmium. (author)

  7. [Arbuscular mycorrhizal symbiosis influences the biological effects of nano-ZnO on maize].

    Science.gov (United States)

    Wang, Wei-Zhong; Wang, Fa-Yuan; Li, Shuai; Liu, Xue-Qin

    2014-08-01

    Engineered nanoparticles (ENPs) can be taken up and accumulated in plants, then enter human bodies via food chain, and thus cause potential health risk. Arbuscular mycorrhizal fungi form mutualistic symbioses with the majority of higher plants in terrestrial ecosystems, and potentially influence the biological effects of ENPs. The present greenhouse pot culture experiment studied the effects of inoculation with or without arbuscular mycorrhizal fungus Acaulospora mellea on growth and nutritional status of maize under different nano-ZnO levels (0, 500, 1 000, 2000 and 3 000 mg x kg(-1)) artificially added into soil. Results showed that with the increasing nano-ZnO levels in soil, mycorrhizal colonization rate and biomass of maize plants showed a decreasing trend, total root length, total surface area and total volume reduced, while Zn concentration and uptake in plants gradually increased, and P, N, K, Fe, and Cu uptake in shoots all decreased. Compared with the controls, arbuscular mycorrhizal inoculation improved the growth and P, N and K nutrition of maize, enhanced total root length, total surface area and total volume, and increased Zn allocation to roots when nano-ZnO was added. Our results firstly show that nano-ZnO in soil induces toxicity to arbuscular mycorrhizae, while arbuscular mycorrhizal inoculation can alleviate its toxicity and play a protective role in plants.

  8. 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.

  9. Decomposition and fertilizing effects of maize stover and chromolaena odorata on maize yield

    International Nuclear Information System (INIS)

    Tetteh, F.M.; Safo, E.Y.; Quansah, C.

    2008-01-01

    The quality, rates of decomposition and the fertilizing effect of chromolaena odorata, and maize stover were determined in field experiments as surface application or buried in litter bags. Studies on the effect of plant materials of contrasting qualities (maize stover and C. odorata) applied sole (10 Mg ha -1 ) and mixed, on maize grain and biomass yield were also conducted on the Asuansi (Ferric Acrisol) soil series. Total nitrogen content of the residues ranged from 0.85% in maize stover to 3.50% in C. odorata. Organic carbon ranged from 34.90% in C. odorata to 48.50% in maize stover. Phosphorus ranged from 0.10% in maize stover to 0.76% in C. odorata. In the wet season, the decomposition rate constants (k) were 0.0319 day -1 for C. odorata, and 0.0081 for maize stover. In the dry season, the k values were 0.0083 for C. odorata, and 0.0072 day -1 for maize stover. Burying of the plant materials reduced the half-life (t 50 ) periods from 18 to 10 days for C. odorata, and 45 to 20 days for maize stover. Maize grain yield of 2556 kg ha -1 was obtained in sole C. odorata (10 Mg ha -1 ) compared with 2167 kg ha -1 for maize stover. Mixing of maize stover and C. odorata residues improved the nutrient content as well as nutrient release by the mixtures resulting in greater maize grain yields in the mixtures than the sole maize stover treatment. It is recommended that C. odorata be used as green manure, mulching or composting material to improve fertility. (au)

  10. Contributions of roots and rootstocks to sustainable, intensified crop production.

    Science.gov (United States)

    Gregory, Peter J; Atkinson, Christopher J; Bengough, A Glyn; Else, Mark A; Fernández-Fernández, Felicidad; Harrison, Richard J; Schmidt, Sonja

    2013-03-01

    Sustainable intensification is seen as the main route for meeting the world's increasing demands for food and fibre. As demands mount for greater efficiency in the use of resources to achieve this goal, so the focus on roots and rootstocks and their role in acquiring water and nutrients, and overcoming pests and pathogens, is increasing. The purpose of this review is to explore some of the ways in which understanding root systems and their interactions with soils could contribute to the development of more sustainable systems of intensive production. Physical interactions with soil particles limit root growth if soils are dense, but root-soil contact is essential for optimal growth and uptake of water and nutrients. X-ray microtomography demonstrated that maize roots elongated more rapidly with increasing root-soil contact, as long as mechanical impedance was not limiting root elongation, while lupin was less sensitive to changes in root-soil contact. In addition to selecting for root architecture and rhizosphere properties, the growth of many plants in cultivated systems is profoundly affected by selection of an appropriate rootstock. Several mechanisms for scion control by rootstocks have been suggested, but the causal signals are still uncertain and may differ between crop species. Linkage map locations for quantitative trait loci for disease resistance and other traits of interest in rootstock breeding are becoming available. Designing root systems and rootstocks for specific environments is becoming a feasible target.

  11. Plant root and shoot dynamics during subsurface obstacle interaction

    Science.gov (United States)

    Conn, Nathaniel; Aguilar, Jeffrey; Benfey, Philip; Goldman, Daniel

    As roots grow, they must navigate complex underground environments to anchor and retrieve water and nutrients. From gravity sensing at the root tip to pressure sensing along the tip and elongation zone, the complex mechanosensory feedback system of the root allows it to bend towards greater depths and avoid obstacles of high impedance by asymmetrically suppressing cell elongation. Here we investigate the mechanical and physiological responses of roots to rigid obstacles. We grow Maize, Zea mays, plants in quasi-2D glass containers (22cm x 17cm x 1.4cm) filled with photoelastic gel and observe that, regardless of obstacle interaction, smaller roots branch off the primary root when the upward growing shoot (which contains the first leaf) reaches an average length of 40 mm, coinciding with when the first leaf emerges. However, prior to branching, contacts with obstacles result in reduced root growth rates. The growth rate of the root relative to the shoot is sensitive to the angle of the obstacle surface, whereby the relative root growth is greatest for horizontally oriented surfaces. We posit that root growth is prioritized when horizontal obstacles are encountered to ensure anchoring and access to nutrients during later stages of development. NSF Physics of Living Systems.

  12. Hydrogen sulfide enhances nitric oxide-induced tolerance of hypoxia in maize (Zea mays L.).

    Science.gov (United States)

    Peng, Renyi; Bian, Zhiyuan; Zhou, Lina; Cheng, Wei; Hai, Na; Yang, Changquan; Yang, Tao; Wang, Xinyu; Wang, Chongying

    2016-11-01

    Our data present H 2 S in a new role, serving as a multi-faceted transducer to different response mechanisms during NO-induced acquisition of tolerance to flooding-induced hypoxia in maize seedling roots. Nitric oxide (NO), serving as a secondary messenger, modulates physiological processes in plants. Recently, hydrogen sulfide (H 2 S) has been demonstrated to have similar signaling functions. This study focused on the effects of treatment with H 2 S on NO-induced hypoxia tolerance in maize seedlings. The results showed that treatment with the NO donor sodium nitroprusside (SNP) enhanced survival rate of submerged maize roots through induced accumulation of endogenous H 2 S. The induced H 2 S then enhanced endogenous Ca 2+ levels as well as the Ca 2+ -dependent activity of alcohol dehydrogenase (ADH), improving the capacity for antioxidant defense and, ultimately, the hypoxia tolerance in maize seedlings. In addition, NO induced the activities of key enzymes in H 2 S biosynthesis, such as L-cysteine desulfhydrases (L-CDs), O-acetyl-L-serine (thiol)lyase (OAS-TL), and β-Cyanoalanine Synthase (CAS). SNP-induced hypoxia tolerance was enhanced by the application of NaHS, but was eliminated by the H 2 S-synthesis inhibitor hydroxylamine (HA) and the H 2 S-scavenger hypotaurine (HT). H 2 S concurrently enhanced the transcriptional levels of relative hypoxia-induced genes. Together, our findings indicated that H 2 S serves as a multi-faceted transducer that enhances the nitric oxide-induced hypoxia tolerance in maize (Zea mays L.).

  13. The influence of gadolinium and yttrium on biomass production and nutrient balance of maize plants

    International Nuclear Information System (INIS)

    Saatz, Jessica; Vetterlein, Doris; Mattusch, Jürgen; Otto, Matthias; Daus, Birgit

    2015-01-01

    Rare earth elements (REE) are expected to become pollutants by enriching in the environment due to their wide applications nowadays. The uptake and distribution of gadolinium and yttrium and its influence on biomass production and nutrient balance was investigated in hydroponic solution experiments with maize plants using increasing application doses of 0.1, 1 and 10 mg L −1 . It could be shown that concentrations of up to 1 mg L −1 of Gd and Y did not reduce or enhance the plant growth or alter the nutrient balance. 10 mg L −1  Gd or Y resulted in REE concentrations of up to 1.2 weight-% in the roots and severe phosphate deficiency symptoms. Transfer rates showed that there was only little transport of Gd and Y from roots to shoots. Significant correlations were found between the concentration of Gd and Y in the nutrient solution and the root tissue concentration of Ca, Mg and P. - Highlights: • Roots accumulate REE in very high concentrations. • Transfer factors from root to shoot tissue are very low, with HREE higher than MREE. • The nutrient balance of the plant is severely influenced by REE addition. • Phosphate deficiency appears at high concentrations of REE addition. - The addition of the rare-earth elements Gd and Y results in less Ca and Mg uptake and phosphate deficiency in maize plants grown in hydroponics

  14. PERFORMANCE OF MAIZE (ZEA MAYS) CULTIVARS AS ...

    African Journals Online (AJOL)

    IBUKUN

    reported to have low remobilisation efficiency and reduced plasticity of seed weight to assimilate availability ... have indicated that the use of organo-mineral fertiliser in maize and melon gave high relative .... The soil physical and chemical characteristics of ..... yield in maize by examining genetic improvement and heterosis.

  15. (SSR) markers for drought tolerance in maize

    African Journals Online (AJOL)

    Maize is moderately sensitive to drought. Drought affects virtually all aspects of maize growth in varying degrees at all stages, from germination to maturity. Tolerance to drought is genetically and physiologically complicated and inherited quantitatively. Application of molecular-marker aided selection technique for ...

  16. Image analysis in the evaluation of the physiological potential of maize seeds1

    Directory of Open Access Journals (Sweden)

    Crislaine Aparecida Gomes Pinto

    Full Text Available The Seed Analysis System (SAS is used in the image analysis of seeds and seedlings, and has the potential for use in the control of seed quality. The aim of this research was to adapt the methodology of image analysis of maize seedlings by SAS, and to verify the potential use of this equipment in the evaluation of the physiological potential of maize seeds. Nine batches of two maize hybrids were characterised by means of the following tests and determinations: germination, first count, accelerated ageing, cold test, seedling emergence at 25 and 30ºC, and speed of emergence index. The image analysis experiment was carried out in a factorial scheme of 9 batches x 4 methods of analysis of the seedling images (with and without the use of NWF as substrate, and with and without manual correction of the images. Images of the seedlings were evaluated using the average lengths of the coleoptile, roots and seedlings; and by the automatic and manual indices of vigour, uniformity and growth produced by the SAS. Use of blue NWF afffects the initial development of maize seedlings. The physiological potential of maize seeds can be evaluated in seedlings which are seeded on white paper towels at a temperature of 25 °C and evaluated on the third day. Image analysis should be carried out with the SAS software using automatic calibration and with no correction of the seedling images. Use of SAS equipment for the analysis of seedling images is a potential tool in evaluating the physiological quality of maize seeds.

  17. Characterization of Indian and exotic quality protein maize (QPM ...

    African Journals Online (AJOL)

    Polymorphism analysis and genetic diversity of normal maize and quality protein maize (QPM) inbreds among locally well adapted germplasm is a prerequisite for hybrid maize breeding program. The diversity analyses of 48 maize accessions including Indian and exotic germplasm using 75 simple sequence repeat (SSR) ...

  18. Exploring maize-legume intercropping systems in Southwest Mexico

    NARCIS (Netherlands)

    Flores-Sanchez, D.; Pastor, A.V.; Lantinga, E.A.; Rossing, W.A.H.; Kropff, M.J.

    2013-01-01

    Maize yields in continuous maize production systems of smallholders in the Costa Chica, a region in Southwest Mexico, are low despite consistent inputs of fertilizers and herbicides. This study was aimed at investigating the prospects of intercropping maize (Zea mays L.) and maize-roselle (Hibiscus

  19. Selection for drought tolerance in two tropical maize populations ...

    African Journals Online (AJOL)

    Drought is a major factor limiting maize (Zea mays L.) yield in much of the world. The need to breed maize cultivars with improved drought tolerance is apparent. This study compared two maize populations, ZM601 and ZM607 for drought tolerance during flowering, the most drought-vulnerable period for the maize plant.

  20. Consumer preferences for maize products in urban Kenya.

    Science.gov (United States)

    De Groote, Hugo; Kimenju, Simon Chege

    2012-06-01

    New maize varieties have been biofortified with provitamin A, mainly a-carotene, which renders the grain yellow or orange. Unfortunately, many African consumers prefer white maize. The maize consumption patterns in Africa are, however, not known. To determine which maize products African consumers prefer to purchase and which maize preparations they prefer to eat. A survey of 600 consumers was conducted in Nairobi, Kenya, at three types of maize outlets: posho mills (small hammer mills), kiosks, and supermarkets. Clients of posho mills had lower incomes and less education than those of kiosks and supermarkets. The preferred maize product of the posho-mill clients was artisanal maize meal; the preferred product of the others was industrial maize meal. Maize is the preferred staple for lunch and dinner, eaten as a stiff porridge (ugali), followed by boiled maize and beans (githeri), regardless of socioeconomic background. For breakfast, only half the consumers prefer maize, mostly as a soft porridge (uji). This proportion is higher in low-income groups. Consumers show a strong preference for white maize over yellow, mostly for its organoleptic characteristics, and show less interest in biofortified maize. Maize is the major food staple in Nairobi, mostly eaten in a few distinct preparations. For biofortified yellow maize to be accepted, a strong public awareness campaign to inform consumers is needed, based on a sensory evaluation and the mass media, in particular on radio in the local language.

  1. Quantitative Trait Loci Mapping of Western Corn Rootworm (Coleoptera: Chrysomelidae) Host Plant Resistance in Two Populations of Doubled Haploid Lines in Maize (Zea mays L.).

    Science.gov (United States)

    Bohn, Martin O; Marroquin, Juan J; Flint-Garcia, Sherry; Dashiell, Kenton; Willmot, David B; Hibbard, Bruce E

    2018-02-09

    Over the last 70 yr, more than 12,000 maize accessions have been screened for their level of resistance to western corn rootworm, Diabrotica virgifera virgifera (LeConte; Coleoptera: Chrysomelidae), larval feeding. Less than 1% of this germplasm was selected for initiating recurrent selection or other breeding programs. Selected genotypes were mostly characterized by large root systems and superior root regrowth after root damage caused by western corn rootworm larvae. However, no hybrids claiming native (i.e., host plant) resistance to western corn rootworm larval feeding are currently commercially available. We investigated the genetic basis of western corn rootworm resistance in maize materials with improved levels of resistance using linkage disequilibrium mapping approaches. Two populations of topcrossed doubled haploid maize lines (DHLs) derived from crosses between resistant and susceptible maize lines were evaluated for their level of resistance in three to four different environments. For each DHL topcross an average root damage score was estimated and used for quantitative trait loci (QTL) analysis. We found genomic regions contributing to western corn rootworm resistance on all maize chromosomes, except for chromosome 4. Models fitting all QTL simultaneously explained about 30 to 50% of the genotypic variance for root damage scores in both mapping populations. Our findings confirm the complex genetic structure of host plant resistance against western corn rootworm larval feeding in maize. Interestingly, three of these QTL regions also carry genes involved in ascorbate biosynthesis, a key compound we hypothesize is involved in the expression of western corn rootworm resistance. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Metabolic profiling of two maize (Zea mays L.) inbred lines inoculated with the nitrogen fixing plant-interacting bacteria Herbaspirillum seropedicae and Azospirillum brasilense

    Science.gov (United States)

    Brusamarello-Santos, Liziane Cristina; Gilard, Françoise; Brulé, Lenaïg; Quilleré, Isabelle; Gourion, Benjamin; Ratet, Pascal; Maltempi de Souza, Emanuel; Lea, Peter J.; Hirel, Bertrand

    2017-01-01

    Maize roots can be colonized by free-living atmospheric nitrogen (N2)-fixing bacteria (diazotrophs). However, the agronomic potential of non-symbiotic N2-fixation in such an economically important species as maize, has still not been fully exploited. A preliminary approach to improve our understanding of the mechanisms controlling the establishment of such N2-fixing associations has been developed, using two maize inbred lines exhibiting different physiological characteristics. The bacterial-plant interaction has been characterized by means of a metabolomic approach. Two established model strains of Nif+ diazotrophic bacteria, Herbaspirillum seropedicae and Azospirillum brasilense and their Nif- couterparts defficient in nitrogenase activity, were used to evaluate the impact of the bacterial inoculation and of N2 fixation on the root and leaf metabolic profiles. The two N2-fixing bacteria have been used to inoculate two genetically distant maize lines (FV252 and FV2), already characterized for their contrasting physiological properties. Using a well-controlled gnotobiotic experimental system that allows inoculation of maize plants with the two diazotrophs in a N-free medium, we demonstrated that both maize lines were efficiently colonized by the two bacterial species. We also showed that in the early stages of plant development, both bacterial strains were able to reduce acetylene, suggesting that they contain functional nitrogenase activity and are able to efficiently fix atmospheric N2 (Fix+). The metabolomic approach allowed the identification of metabolites in the two maize lines that were representative of the N2 fixing plant-bacterial interaction, these included mannitol and to a lesser extend trehalose and isocitrate. Whilst other metabolites such as asparagine, although only exhibiting a small increase in maize roots following bacterial infection, were specific for the two Fix+ bacterial strains, in comparison to their Fix- counterparts. Moreover, a number

  3. Metabolic profiling of two maize (Zea mays L. inbred lines inoculated with the nitrogen fixing plant-interacting bacteria Herbaspirillum seropedicae and Azospirillum brasilense.

    Directory of Open Access Journals (Sweden)

    Liziane Cristina Brusamarello-Santos

    Full Text Available Maize roots can be colonized by free-living atmospheric nitrogen (N2-fixing bacteria (diazotrophs. However, the agronomic potential of non-symbiotic N2-fixation in such an economically important species as maize, has still not been fully exploited. A preliminary approach to improve our understanding of the mechanisms controlling the establishment of such N2-fixing associations has been developed, using two maize inbred lines exhibiting different physiological characteristics. The bacterial-plant interaction has been characterized by means of a metabolomic approach. Two established model strains of Nif+ diazotrophic bacteria, Herbaspirillum seropedicae and Azospirillum brasilense and their Nif- couterparts defficient in nitrogenase activity, were used to evaluate the impact of the bacterial inoculation and of N2 fixation on the root and leaf metabolic profiles. The two N2-fixing bacteria have been used to inoculate two genetically distant maize lines (FV252 and FV2, already characterized for their contrasting physiological properties. Using a well-controlled gnotobiotic experimental system that allows inoculation of maize plants with the two diazotrophs in a N-free medium, we demonstrated that both maize lines were efficiently colonized by the two bacterial species. We also showed that in the early stages of plant development, both bacterial strains were able to reduce acetylene, suggesting that they contain functional nitrogenase activity and are able to efficiently fix atmospheric N2 (Fix+. The metabolomic approach allowed the identification of metabolites in the two maize lines that were representative of the N2 fixing plant-bacterial interaction, these included mannitol and to a lesser extend trehalose and isocitrate. Whilst other metabolites such as asparagine, although only exhibiting a small increase in maize roots following bacterial infection, were specific for the two Fix+ bacterial strains, in comparison to their Fix- counterparts

  4. Metabolic profiling of two maize (Zea mays L.) inbred lines inoculated with the nitrogen fixing plant-interacting bacteria Herbaspirillum seropedicae and Azospirillum brasilense.

    Science.gov (United States)

    Brusamarello-Santos, Liziane Cristina; Gilard, Françoise; Brulé, Lenaïg; Quilleré, Isabelle; Gourion, Benjamin; Ratet, Pascal; Maltempi de Souza, Emanuel; Lea, Peter J; Hirel, Bertrand

    2017-01-01

    Maize roots can be colonized by free-living atmospheric nitrogen (N2)-fixing bacteria (diazotrophs). However, the agronomic potential of non-symbiotic N2-fixation in such an economically important species as maize, has still not been fully exploited. A preliminary approach to improve our understanding of the mechanisms controlling the establishment of such N2-fixing associations has been developed, using two maize inbred lines exhibiting different physiological characteristics. The bacterial-plant interaction has been characterized by means of a metabolomic approach. Two established model strains of Nif+ diazotrophic bacteria, Herbaspirillum seropedicae and Azospirillum brasilense and their Nif- couterparts defficient in nitrogenase activity, were used to evaluate the impact of the bacterial inoculation and of N2 fixation on the root and leaf metabolic profiles. The two N2-fixing bacteria have been used to inoculate two genetically distant maize lines (FV252 and FV2), already characterized for their contrasting physiological properties. Using a well-controlled gnotobiotic experimental system that allows inoculation of maize plants with the two diazotrophs in a N-free medium, we demonstrated that both maize lines were efficiently colonized by the two bacterial species. We also showed that in the early stages of plant development, both bacterial strains were able to reduce acetylene, suggesting that they contain functional nitrogenase activity and are able to efficiently fix atmospheric N2 (Fix+). The metabolomic approach allowed the identification of metabolites in the two maize lines that were representative of the N2 fixing plant-bacterial interaction, these included mannitol and to a lesser extend trehalose and isocitrate. Whilst other metabolites such as asparagine, although only exhibiting a small increase in maize roots following bacterial infection, were specific for the two Fix+ bacterial strains, in comparison to their Fix- counterparts. Moreover, a number

  5. Impact of Cry3Bb1-expressing Bt maize on adults of the western corn rootworm, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae).

    Science.gov (United States)

    Meissle, Michael; Hellmich, Richard L; Romeis, Jörg

    2011-07-01

    Genetically engineered maize producing insecticidal Cry3Bb1 protein from Bacillus thuringiensis (Bt) is protected from root damage by corn rootworm larvae. An examination was made to establish whether western corn rootworm (Diabrotica virgifera virgifera) adults are affected by Cry3Bb1-expressing maize (MON88017) when feeding on above-ground tissue. In laboratory bioassays, adult D. v. virgifera were fed for 7 weeks with silk, leaves or pollen from Bt maize or the corresponding near-isoline. Male, but not female, survival was reduced in the Bt-leaf treatment compared with the control. Female weight was lower when fed Bt maize, and egg production was reduced in the Bt-silk treatment. ELISA measurements demonstrated that beetles feeding on silk were exposed to higher Cry3Bb1 concentrations than beetles collected from Bt-maize fields in the United States. In contrast to silk and pollen, feeding on leaves resulted in high mortality and low fecundity. Females feeding on pollen produced more eggs than on silk. C:N ratios indicated that silk does not provide enough nitrogen for optimal egg production. Direct effects of Cry3Bb1 on adult beetles could explain the observed effects, but varietal differences between Bt and control maize are also possible. The impact of Bt maize on adult populations, however, is likely to be limited. Copyright © 2011 Society of Chemical Industry.

  6. Risk Adjusted Production Efficiency of Maize Farmers in Ethiopia: Implication for Improved Maize Varieties Adoption

    Directory of Open Access Journals (Sweden)

    Sisay Diriba Lemessa

    2017-09-01

    Full Text Available This study analyzes the technical efficiency and production risk of 862 maize farmers in major maize producing regions of Ethiopia. It employs the stochastic frontier approach (SFA to estimate the level of technical efficiencies of stallholder farmers. The stochastic frontier approach (SFA uses flexible risk properties to account for production risk. Thus, maize production variability is assessed from two perspectives, the production risk and the technical efficiency. The study also attempts to determine the socio-economic and farm characteristics that influence technical efficiency of maize production in the study area. The findings of the study showed the existence of both production risk and technical inefficiency in maize production process. Input variables (amounts per hectare such as fertilizer and labor positively influence maize output. The findings also show that farms in the study area exhibit decreasing returns to scale. Fertilizer and ox plough days reduce output risk while labor and improved seed increase output risk. The mean technical efficiency for maize farms is 48 percent. This study concludes that production risk and technical inefficiency prevents the maize farmers from realizing their frontier output. The best factors that improve the efficiency of the maize farmers in the study area include: frequency of extension contact, access to credit and use of intercropping. It was also realized that altitude and terracing in maize farms had influence on farmer efficiency.

  7. INTEGRATED WEED CONTROL IN MAIZE.

    Science.gov (United States)

    Latré, J; Dewitte, K; Derycke, V; De Roo, B; Haesaert, G

    2015-01-01

    Integrated pest management has been implemented as a general practice by EU legislation. As weed control actually is the most important crop protection measure in maize for Western Europe, the new legislation will have its impact. The question is of course which systems can be successfully implemented in practice with respect to labour efficiency and economical parameters. During 3 successive growing seasons (2007, 2008, 2009) weed control in maize was evaluated, the main focus was put on different techniques of integrated weed control and was compared with chemical weed control. Additionally, during 4 successive growing seasons (2011, 2012, 2013 and 2014) two objects based on integrated weed control and two objects based on mechanical weed control were compared to about twenty different objects of conventional chemical weed control. One of the objects based on mechanical weed control consisted of treatment with the flex-tine harrow before and after emergence in combination with chemical weed control at a reduced rate in 3-4 leave stage. The second one consisted of broadcast mechanical treatments before and after emergence followed by a final in-row application of herbicides and an inter-row cultivation at 6-7(8) leave stage. All trials were conducted on the Experimental farm of Bottelare HoGent-UGent on a sandy loam soil. Maize was growing in 1/3 crop rotation. The effect on weed growth as well as the economic impact of the different applications was evaluated. Combining chemical and mechanical weed control is a possible option in conventional farming but the disadvantages must be taken into account. A better planned weed control based on the real present weed-population in combination with a carefully thought-out choice of herbicides should also be considered as an IPM--approach.

  8. Carbaryl residues in maize products

    International Nuclear Information System (INIS)

    Zayed, S.M.A.D.; Mansour, S.A.; Mostafa, I.Y.; Hassan, A.

    1976-01-01

    The 14 C-labelled insecticide carbaryl was synthesized from [1- 14 C]-1-naphthol at a specific activity of 3.18mCig -1 . Maize plants were treated with the labelled insecticide under simulated conditions of agricultural practice. Mature plants were harvested and studied for distribution of total residues in untreated grains as popularly roasted and consumed, and in the corn oil and corn germ products. Total residues found under these conditions in the respective products were 0.2, 0.1, 0.45 and 0.16ppm. (author)

  9. Compatible bacterial mixture, tolerant to desiccation, improves maize plant growth.

    Science.gov (United States)

    Molina-Romero, Dalia; Baez, Antonino; Quintero-Hernández, Verónica; Castañeda-Lucio, Miguel; Fuentes-Ramírez, Luis Ernesto; Bustillos-Cristales, María Del Rocío; Rodríguez-Andrade, Osvaldo; Morales-García, Yolanda Elizabeth; Munive, Antonio; Muñoz-Rojas, Jesús

    2017-01-01

    Plant growth-promoting rhizobacteria (PGPR) increase plant growth and crop productivity. The inoculation of plants with a bacterial mixture (consortium) apparently provides greater benefits to plant growth than inoculation with a single bacterial strain. In the present work, a bacterial consortium was formulated containing four compatible and desiccation-tolerant strains with potential as PGPR. The formulation had one moderately (Pseudomonas putida KT2440) and three highly desiccation-tolerant (Sphingomonas sp. OF178, Azospirillum brasilense Sp7 and Acinetobacter sp. EMM02) strains. The four bacterial strains were able to adhere to seeds and colonize the rhizosphere of plants when applied in both mono-inoculation and multi-inoculation treatments, showing that they can also coexist without antagonistic effects in association with plants. The effects of the bacterial consortium on the growth of blue maize were evaluated. Seeds inoculated with either individual bacterial strains or the bacterial consortium were subjected to two experimental conditions before sowing: normal hydration or desiccation. In general, inoculation with the bacterial consortium increased the shoot and root dry weight, plant height and plant diameter compared to the non-inoculated control or mono-inoculation treatments. The bacterial consortium formulated in this work had greater benefits for blue maize plants even when the inoculated seeds underwent desiccation stress before germination, making this formulation attractive for future field applications.

  10. Compatible bacterial mixture, tolerant to desiccation, improves maize plant growth.

    Directory of Open Access Journals (Sweden)

    Dalia Molina-Romero

    Full Text Available Plant growth-promoting rhizobacteria (PGPR increase plant growth and crop productivity. The inoculation of plants with a bacterial mixture (consortium apparently provides greater benefits to plant growth than inoculation with a single bacterial strain. In the present work, a bacterial consortium was formulated containing four compatible and desiccation-tolerant strains with potential as PGPR. The formulation had one moderately (Pseudomonas putida KT2440 and three highly desiccation-tolerant (Sphingomonas sp. OF178, Azospirillum brasilense Sp7 and Acinetobacter sp. EMM02 strains. The four bacterial strains were able to adhere to seeds and colonize the rhizosphere of plants when applied in both mono-inoculation and multi-inoculation treatments, showing that they can also coexist without antagonistic effects in association with plants. The effects of the bacterial consortium on the growth of blue maize were evaluated. Seeds inoculated with either individual bacterial strains or the bacterial consortium were subjected to two experimental conditions before sowing: normal hydration or desiccation. In general, inoculation with the bacterial consortium increased the shoot and root dry weight, plant height and plant diameter compared to the non-inoculated control or mono-inoculation treatments. The bacterial consortium formulated in this work had greater benefits for blue maize plants even when the inoculated seeds underwent desiccation stress before germination, making this formulation attractive for future field applications.

  11. Effects of maize planting patterns on the performance of cassava ...

    African Journals Online (AJOL)

    sola

    The design was a split-plot arrangement, laid out in a randomized ... significant differences (P<0.05) between the treatments in the growth and yield parameters of maize. The mean effects of companion crops on maize leaf area were 0.61, 0.60, 0.60 and 0.52 m2/plant for sole maize, maize / melon, maize / cassava and.

  12. Characteristics and mechanisms of acrylate polymer damage to maize seedlings.

    Science.gov (United States)

    Chen, Xian; Mao, Xiaoyun; Lu, Qin; Liao, Zongwen; He, Zhenli

    2016-07-01

    Superabsorbent acrylate polymers (SAPs) have been widely used to maintain soil moisture in agricultural management, but they may cause damage to plants, and the mechanisms are not well understood. In this study, seed germination, soil pot culture, hydroponic experiments, and SAPs degradation were conducted to investigate damage characteristics and mechanisms associated with SAPs application. The Results showed that SAPs inhibited maize growth and altered root morphology (irregular and loose arrangement of cells and breakage of cortex parenchyma), and the inhibitory effects were enhanced at higher SAPs rates. After 1h SAP hydrogels treatment, root malondialdehyde (MDA) content was significantly increased, while superoxide dismutase (SOD) and catalase (CAT) content were significantly decreased. Hydroponics experiment indicated that root and shoot growth was inhibited at 2.5mgL(-1) acrylic acid (AA), and the inhibition was enhanced with increasing AA rates. This effect was exacerbated by the presence of Na(+) at a high concentration in the hydrogels. Release and degradation of AA were enhanced at higher soil moisture levels. A complete degradation of AA occurred between 15 and 20 days after incubation (DAI), but it took longer for Na(+) concentration to decrease to a safe level. These results indicate that high concentration of both AA and Na(+) present in the SAPs inhibits plant growth. The finding of this study may provide a guideline for appropriate application of SAPs in agriculture. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. RNA-Seq Analysis Reveals MAPKKK Family Members Related to Drought Tolerance in Maize

    Science.gov (United States)

    Ren, Wen; Yang, Fengling; He, Hang; Zhao, Jiuran

    2015-01-01

    The mitogen-activated protein kinase (MAPK) cascade is an evolutionarily conserved signal transduction pathway that is involved in plant development and stress responses. As the first component of this phosphorelay cascade, mitogen-activated protein kinase kinase kinases (MAPKKKs) act as adaptors linking upstream signaling steps to the core MAPK cascade to promote the appropriate cellular responses; however, the functions of MAPKKKs in maize are unclear. Here, we identified 71 MAPKKK genes, of which 14 were novel, based on a computational analysis of the maize (Zea mays L.) genome. Using an RNA-seq analysis in the leaf, stem and root of maize under well-watered and drought-stress conditions, we identified 5,866 differentially expressed genes (DEGs), including 8 MAPKKK genes responsive to drought stress. Many of the DEGs were enriched in processes such as drought stress, abiotic stimulus, oxidation-reduction, and metabolic processes. The other way round, DEGs involved in processes such as oxidation, photosynthesis, and starch, proline, ethylene, and salicylic acid metabolism were clearly co-expressed with the MAPKKK genes. Furthermore, a quantitative real-time PCR (qRT-PCR) analysis was performed to assess the relative expression levels of MAPKKKs. Correlation analysis revealed that there was a significant correlation between expression levels of two MAPKKKs and relative biomass responsive to drought in 8 inbred lines. Our results indicate that MAPKKKs may have important regulatory functions in drought tolerance in maize. PMID:26599013

  14. Effect of Salicylic Acid on the Growth and Physiological Characteristics of Maize under Stress Conditions

    International Nuclear Information System (INIS)

    Manzoor, K.; Ilyas, N.; Batool, N.; Arshad, M.; Ahmad, B.

    2015-01-01

    Salicylic acid (SA) is a naturally occurring signaling molecule and growth regulator that enhances plant growth particularly in stress conditions. The present study was planned to evaluate the effects of different levels of SA on maize growth under drought and salt stress conditions. An experiment was conducted to test the morphological, physiological and biochemical changes in two cultivar of maize D-1184 and TG-8250. Varying levels of salicylic acid, i.e. 5mM, 10mM and 15mM were applied through foliar method. Exogenous applications of salicylic acid were done after 20 days of germination of the maize plants. Salicylic acid significantly affects root and shoot dry matter under drought and salt stress. Foliar application of SA significantly increased proline concentration (11 percentage and 12 percentage), amino acid accumulation (25 percentage and 18 percentage), relative water (17 percentage and 14 percentage) and Chlorophyll content. Overall, it can be concluded that SA at lower concentration is effective to minimize the effect of stress conditions. Maize cultivar TG-8250 showed better tolerance under drought and salt stress condition as compared to D-1184 cultivar. (author)

  15. Effects Of Irrigation With Saline Water, And Soil Type On Germination And Seedling Growth Of Sweet Maize (Zea Mays L.)

    International Nuclear Information System (INIS)

    Mostafa, A.Z.; Amato, M.; Hamdi, A.; Mostafa, A.Z.; Galal, Y.G.M.; Lotfy, S.M.

    2012-01-01

    Germination and early growth of maize Sweet Maize (Zea mays L.), var. (SEL. CONETA) under irrigation with saline water were investigated in a pot experiment with different soil types. Seven salinity levels of irrigation water up to 12 dS/m were used on a Clay soil (C) and a Sandy-Loam (SL). Emergence of maize was delayed under irrigation with saline water, and the final percentage of germination was reduced only at 8 dS/m or above. Seedling shoot and root growth were reduced starting at 4 dS/m of irrigation water. Salts accumulated more in the C soil but reductions in final germination rate and seedling growth were larger in the SL soil, although differences were not always significant. Data indicate that germination is rather tolerant to salinity level in var. SEL. CONETA whereas seedling growth is reduced at moderate salinity levels, and that soil type affects plant performance under irrigation with saline water

  16. A maize gene encoding an NADPH binding enzyme highly homologous to isoflavone reductases is activated in response to sulfur starvation.

    Science.gov (United States)

    Petrucco, S; Bolchi, A; Foroni, C; Percudani, R; Rossi, G L; Ottonello, S

    1996-01-01

    we isolated a novel gene that is selectively induced both in roots and shoots in response to sulfur starvation. This gene encodes a cytosolic, monomeric protein of 33 kD that selectively binds NADPH. The predicted polypeptide is highly homologous ( > 70%) to leguminous isoflavone reductases (IFRs), but the maize protein (IRL for isoflavone reductase-like) belongs to a novel family of proteins present in a variety of plants. Anti-IRL antibodies specifically recognize IFR polypeptides, yet the maize protein is unable to use various isoflavonoids as substrates. IRL expression is correlated closely to glutathione availability: it is persistently induced in seedlings whose glutathione content is about fourfold lower than controls, and it is down-regulated rapidly when control levels of glutathione are restored. This glutathione-dependent regulation indicates that maize IRL may play a crucial role in the establishment of a thiol-independent response to oxidative stress under glutathione shortage conditions.

  17. Impacts of deficit irrigation and altered rooting patterns on soil structure and associated soil properties

    Science.gov (United States)

    A better understanding of belowground systems and overall management impacts on soil health is needed to improve crop production and long-term sustainability under deficit irrigation. This study investigates effects of deficit irrigation on rooting patterns in maize and subsequent impacts on soil pr...

  18. 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...

  19. Effect of Pakistan lignitic derived humic acids on the agriculture growth part II: studies on the effect of humic acids on the growth, yield and protein content of maize

    International Nuclear Information System (INIS)

    Ahmed, N.; Abbasi, Y.Z.; Mir, S.

    1994-01-01

    The effect of various minute concentrations of humic acids on the growth, yield and protein contents of maize were studied. The results revealed that the humic acid application in small doses produce higher grain yield, more protein content and better developed plants and roots compared to control. There was a positive correlation between the grain yield, protein contents and plant growth of maize to different levels of humic acid application. (author)

  20. Seed priming with KNO3 mediates biochemical processes to inhibit lead toxicity in maize (Zea mays L.).

    Science.gov (United States)

    Nawaz, Fahim; Naeem, Muhammad; Akram, Asim; Ashraf, Muhammad Y; Ahmad, Khawaja S; Zulfiqar, Bilal; Sardar, Hasan; Shabbir, Rana N; Majeed, Sadia; Shehzad, Muhammad A; Anwar, Irfan

    2017-11-01

    Accumulation of lead (Pb) in agricultural soils has become a major factor for reduced crop yields and poses serious threats to humans consuming agricultural products. The present study investigated the effects of KNO 3 seed priming (0 and 0.5% KNO 3 ) on growth of maize (Zea mays L.) seedlings exposed to Pb toxicity (0, 1300 and 2550 mg kg -1 Pb). Pb exposure markedly reduced the growth of maize seedlings and resulted in higher Pb accumulation in roots than shoots. Pretreatment of seeds with KNO 3 significantly improved the germination percentage and increased physiological indices. A stimulating effect of KNO 3 seed priming was also observed on pigments (chlorophyll a, b, total chlorophyll and carotenoid contents) of Pb-stressed plants. Low translocation of Pb from roots to shoots caused an increased accumulation of total free amino acids and higher activities of catalase, peroxidase, superoxide dismutase and ascorbate peroxidase in roots as compared to shoot, which were further enhanced by exogenous KNO 3 supply to prevent Pb toxicity. Maize accumulates more Pb in roots than shoot at early growth stages. Priming of seeds with KNO 3 prevents Pb toxicity, which may be exploited to improve seedling establishment in crop species grown under Pb contaminated soils. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  1. Constitutive expression of fluorescent protein by Aspergillus var. niger and Aspergillus carbonarius to monitor fungal colonization in maize plants.

    Science.gov (United States)

    Palencia, Edwin Rene; Glenn, Anthony Elbie; Hinton, Dorothy Mae; Bacon, Charles Wilson

    2013-09-01

    Aspergillus niger and Aspergillus carbonarius are two species in the Aspergillus section Nigri (black-spored aspergilli) frequently associated with peanut (Arachis hypogea), maize (Zea mays), and other plants as pathogens. These infections are symptomless and as such are major concerns since some black aspergilli produce important mycotoxins, ochratoxins A, and the fumonisins. To facilitate the study of the black aspergilli-maize interactions with maize during the early stages of infections, we developed a method that used the enhanced yellow fluorescent protein (eYFP) and the monomeric red fluorescent protein (mRFP1) to transform A. niger and A. carbonarius, respectively. The results were constitutive expressions of the fluorescent genes that were stable in the cytoplasms of hyphae and conidia under natural environmental conditions. The hyphal in planta distribution in 21-day-old seedlings of maize were similar wild type and transformants of A. niger and A. carbonarius. The in planta studies indicated that both wild type and transformants internally colonized leaf, stem and root tissues of maize seedlings, without any visible disease symptoms. Yellow and red fluorescent strains were capable of invading epidermal cells of maize roots intercellularly within the first 3 days after inoculation, but intracellular hyphal growth was more evident after 7 days of inoculation. We also tested the capacity of fluorescent transformants to produce ochratoxin A and the results with A. carbonarius showed that this transgenic strain produced similar concentrations of this secondary metabolite. This is the first report on the in planta expression of fluorescent proteins that should be useful to study the internal plant colonization patterns of two ochratoxigenic species in the Aspergillus section Nigri. © 2013.

  2. Biosynthesis of DIMBOA in maize using deuterium oxide as a tracer

    International Nuclear Information System (INIS)

    Peng, S.; Chilton, W.S.

    1994-01-01

    Growth of root cultures and of shoot cultures of maize (Zea mays) was noticeably inhibited by 30% D2O in liquid medium. Increasing the concentration of D2O in the medium decreased the concentration of DIMBOA [2,4-dihydroxy-7-methoxy 2H-1,4-benzoxazin-3(4H)-one] and the biomass of roots and shoots. DIMBOA was converted to MBOA [6-methoxy-2(3H)-benzoxazolone] and analysed by mass spectroscopy. Both root cultures and shoot cultures grown on 30% D2O incorporated deuterium at non-exchangeable sites of MBOA (15.6% and 16.1%, respectively), indicating that maize roots and shoots are independently capable of synthesizing DIMBOA from carbohydrate precursors. EI-MS and H-1 NMR showed that there was little selectivity in deuterium labelling between hydrogens at aromatic position 4, 5 or 7, consistent with the major amount of deuterium incorporation occurring prior to synthesis of shikimic acid

  3. Screening of promising maize genotypes against maize weevil (Sitophilus zeamais Motschulky) in storage condition

    OpenAIRE

    Ram B Paneru; Resham B Thapa

    2017-01-01

    The maize weevil (Sitophilus zeamais Motschulsky) is a serious pest of economic importance in stored grains. It causes major damage to stored maize grain thereby reducing its weight, quality and germination. An experiment was conducted in randomized complete block design (RCBD) with 3 replications to screen 32 maize genotypes against maize weevil in no-choice and free-choice conditions at Entomology Division, Khumaltar, Lalitpur (Room temperature: Maximum 24-32°C and Minimum 18-27°C). The fin...

  4. Comparison of Selenium Toxicity in Sunflower and Maize Seedlings Grown in Hydroponic Cultures.

    Science.gov (United States)

    Garousi, Farzaneh; Veres, Szilvia; Kovács, Béla

    2016-11-01

    Several studies have demonstrated that selenium (Se) at low concentrations is beneficial, whereas high Se concentrations can induce toxicity. Controlling Se uptake, metabolism, translocation and accumulation in plants is important to decrease potential health risks and helping to select proper biofortification methods to improve the nutritional content of plant-based foods. The uptake and distribution of Se, changes in Se content, and effects of various concentrations of Se in two forms (sodium selenite and sodium selenate) on sunflower and maize plants were measured in nutrient solution experiments. Results revealed the Se content in shoots and roots of both sunflower and maize plants significantly increased as the Se level increased. In this study, the highest exposure concentrations (30 and 90 mg/L, respectively) caused toxicity in both sunflower and maize. While both Se forms damaged and inhibited plant growth, each behaved differently, as toxicity due to selenite was observed more than in the selenate treatments. Sunflower demonstrated a high Se accumulation capacity, with higher translocation of selenate from roots to shoots compared with selenite. Since in seleniferous soils, a high change in plants' capability exists to uptake Se from these soils and also most of the cultivated crop plants have a bit tolerance to high Se levels, distinction of plants with different Se tolerance is important. This study has tried to discuss about it.

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

    Science.gov (United States)

    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.

  6. Novel scanning procedure enabling the vectorization of entire rhizotron-grown root systems

    Directory of Open Access Journals (Sweden)

    Lobet Guillaume

    2013-01-01

    Full Text Available Abstract This paper presents an original spit-and-combine imaging procedure that enables the complete vectorization of complex root systems grown in rhizotrons. The general principle of the method is to (1 separate the root system into a small number of large pieces to reduce root overlap, (2 scan these pieces one by one, (3 analyze separate images with a root tracing software and (4 combine all tracings into a single vectorized root system. This method generates a rich dataset containing morphological, topological and geometrical information of entire root systems grown in rhizotrons. The utility of the method is illustrated with a detailed architectural analysis of a 20-day old maize root system, coupled with a spatial analysis of water uptake patterns.

  7. Novel scanning procedure enabling the vectorization of entire rhizotron-grown root systems.

    Science.gov (United States)

    Lobet, Guillaume; Draye, Xavier

    2013-01-04

    : This paper presents an original spit-and-combine imaging procedure that enables the complete vectorization of complex root systems grown in rhizotrons. The general principle of the method is to (1) separate the root system into a small number of large pieces to reduce root overlap, (2) scan these pieces one by one, (3) analyze separate images with a root tracing software and (4) combine all tracings into a single vectorized root system. This method generates a rich dataset containing morphological, topological and geometrical information of entire root systems grown in rhizotrons. The utility of the method is illustrated with a detailed architectural analysis of a 20-day old maize root system, coupled with a spatial analysis of water uptake patterns.

  8. Water movement through plant roots - exact solutions of the water flow equation in roots with linear or exponential piecewise hydraulic properties

    Science.gov (United States)

    Meunier, Félicien; Couvreur, Valentin; Draye, Xavier; Zarebanadkouki, Mohsen; Vanderborght, Jan; Javaux, Mathieu

    2017-12-01

    In 1978, Landsberg and Fowkes presented a solution of the water flow equation inside a root with uniform hydraulic properties. These properties are root radial conductivity and axial conductance, which control, respectively, the radial water flow between the root surface and xylem and the axial flow within the xylem. From the solution for the xylem water potential, functions that describe the radial and axial flow along the root axis were derived. These solutions can also be used to derive root macroscopic parameters that are potential input parameters of hydrological and crop models. In this paper, novel analytical solutions of the water flow equation are developed for roots whose hydraulic properties vary along their axis, which is the case for most plants. We derived solutions for single roots with linear or exponential variations of hydraulic properties with distance to root tip. These solutions were subsequently combined to construct single roots with complex hydraulic property profiles. The analytical solutions allow one to verify numerical solutions and to get a generalization of the hydric behaviour with the main influencing parameters of the solutions. The resulting flow distributions in heterogeneous roots differed from those in uniform roots and simulations led to more regular, less abrupt variations of xylem suction or radial flux along root axes. The model could successfully be applied to maize effective root conductance measurements to derive radial and axial hydraulic properties. We also show that very contrasted root water uptake patterns arise when using either uniform or heterogeneous root hydraulic properties in a soil-root model. The optimal root radius that maximizes water uptake under a carbon cost constraint was also studied. The optimal radius was shown to be highly dependent on the root hydraulic properties and close to observed properties in maize roots. We finally used the obtained functions for evaluating the impact of root maturation

  9. Water movement through plant roots – exact solutions of the water flow equation in roots with linear or exponential piecewise hydraulic properties

    Directory of Open Access Journals (Sweden)

    F. Meunier

    2017-12-01

    Full Text Available In 1978, Landsberg and Fowkes presented a solution of the water flow equation inside a root with uniform hydraulic properties. These properties are root radial conductivity and axial conductance, which control, respectively, the radial water flow between the root surface and xylem and the axial flow within the xylem. From the solution for the xylem water potential, functions that describe the radial and axial flow along the root axis were derived. These solutions can also be used to derive root macroscopic parameters that are potential input parameters of hydrological and crop models. In this paper, novel analytical solutions of the water flow equation are developed for roots whose hydraulic properties vary along their axis, which is the case for most plants. We derived solutions for single roots with linear or exponential variations of hydraulic properties with distance to root tip. These solutions were subsequently combined to construct single roots with complex hydraulic property profiles. The analytical solutions allow one to verify numerical solutions and to get a generalization of the hydric behaviour with the main influencing parameters of the solutions. The resulting flow distributions in heterogeneous roots differed from those in uniform roots and simulations led to more regular, less abrupt variations of xylem suction or radial flux along root axes. The model could successfully be applied to maize effective root conductance measurements to derive radial and axial hydraulic properties. We also show that very contrasted root water uptake patterns arise when using either uniform or heterogeneous root hydraulic properties in a soil–root model. The optimal root radius that maximizes water uptake under a carbon cost constraint was also studied. The optimal radius was shown to be highly dependent on the root hydraulic properties and close to observed properties in maize roots. We finally used the obtained functions for evaluating the impact

  10. Dynamics of phosphorus fractions in the rhizosphere of fababean (Phaseolus vulgaris L.) and maize (Zea mays L.) grown in calcareous and acid soils

    NARCIS (Netherlands)

    Li, G.; Li, Haigang; Leffelaar, P.A.; Shen, J.; Zhang, F.

    2015-01-01

    The dynamics of soil phosphorus (P) fractions were investigated, in the rhizosphere of fababean (Vicia faba L.) and maize (Zea mays L.) grown in calcareous and acid soils. Plants were grown in a mini-rhizotron with a thin (3 mm) soil layer, which was in contact with the root-mat, and considered as

  11. Analysis of DNA methylation of maize in response to osmotic and salt stress based on methylation-sensitive amplified polymorphism.

    Science.gov (United States)

    Tan, Ming-pu

    2010-01-01

    Water stress is known to alter cytosine methylation, which generally represses transcription. However, little is known about the role of methylation alteration in maize under osmotic stress. Here, methylation-sensitive amplified polymorphism (MSAP) was used to screen PEG- or NaCl-induced methylation alteration in maize seedlings. The sequences of 25 differentially amplified fragments relevant to stress were successfully obtained. Two stress-specific fragments from leaves, LP166 and LPS911, shown to be homologous to retrotransposon Gag-Pol protein genes, suggested that osmotic stress-induced methylation of retrotransposons. Three MSAP fragments, representing drought-induced or salt-induced methylation in leaves, were homologous to a maize aluminum-induced transporter. Besides these, heat shock protein HSP82, Poly [ADP-ribose] polymerase 2, Lipoxygenase, casein kinase (CK2), and dehydration-responsive element-binding (DREB) factor were also homologs of MSAP sequences from salt-treated roots. One MSAP fragment amplified from salt-treated roots, designated RS39, was homologous to the first intron of maize protein phosphatase 2C (zmPP2C), whereas - LS103, absent from salt-treated leaves, was homologous to maize glutathione S-transferases (zmGST). Expression analysis showed that salt-induced intron methylation of root zmPP2C significantly downregulated its expression, while salt-induced demethylation of leaf zmGST weakly upregulated its expression. The results suggested that salinity-induced methylation downregulated zmPP2C expression, a negative regulator of the stress response, while salinity-induced demethylation upregulated zmGST expression, a positive effecter of the stress response. Altered methylation, in response to stress, might also be involved in stress acclimation. Copyright 2009 Elsevier Masson SAS. All rights reserved.

  12. [Influences of micro-irrigation and subsoiling before planting on enzyme activity in soil rhizosphere and summer maize yield.

    Science.gov (United States)

    Zhang, Ming Zhi; Niu, Wen Quan; Xu, Jian; Li, Yuan

    2016-06-01

    In order to explore the influences of micro-irrigation and subsoiling before planting on enzyme activity in soil rhizosphere and summer maize yield, an orthogonal experiment was carried out with three factors of micro-irrigation method, irrigation depth, and subsoiling depth. The factor of irrigation method included surface drip irrigation, subsurface drip irrigation, and moistube-irrigation; three levels of irrigation depth were obtained by controlling the lower limit of soil water content to 50%, 65%, and 80% of field holding capacity, respectively; and three depths of deep subsoiling were 20, 40, and 60 cm. The results showed that the activities of catalase and urease increased first and then decreased, while the activity of phosphatase followed an opposite trend in the growth season of summer maize. Compared with surface drip irrigation and moistube-irrigation, subsurface drip irrigation increased the average soil moisture of 0-80 cm layer by 6.3% and 1.8% in the growth season, respectively. Subsurface drip irrigation could significantly increase soil urease activity, roots volume, and yield of summer maize. With the increase of irrigation level, soil phosphatase activity decreased first and then increased, while urease activity and yield increased first and then decreased. The average soil moisture and root volume all increased in the growth season of summer maize. The increments of yield and root volume from subsoiling of 40 to 20 cm were greater than those from 60 to 40 cm. The highest enzyme activity was obtained with the treatment of subsoiling of 40 cm. In terms of improving water resource use efficiency, nitrogen use efficiency, and crop yield, the best management strategy of summer maize was the combination of subsurface drip irrigation, controlling the lower limit of soil water content to 65% of field holding capacity, and 40 cm subsoiling before planting.

  13. Isolation and Screening of Bacteria for Their Diazotrophic Potential and Their Influence on Growth Promotion of Maize Seedlings in Greenhouses.

    Science.gov (United States)

    Kifle, Medhin H; Laing, Mark D

    2015-01-01

    Poor soil fertility is one of the major constraints for crop production. Nitrogen is the most limiting nutrient for increasing crop productivity. Therefore, there is a need to identify diazotrophic inoculants as an alternative or supplement to N-fertilizers for sustainable agriculture. In the current study, a number of free-living diazotrophic bacteria were isolated from soils collected from maize rhizosphere and from leaves and roots of maize within the KwaZulu-Natal Province, Republic of South Africa. Ninety-two isolates were selected for further screening because they were able to grow on N-free media containing different carbon sources. Isolates that were very slow to grow on N-free media were discarded. The isolates were screened in vitro for diazotrophic potential tests for ammonia production and acetylene reduction. Ethylene (C2H4) production was quantified and ranged from 4 to 73 nmoles of C2H4h(-1) culture(-1). The top 20 isolates were re-screened on maize seedlings, and eight isolates significantly (P = 0.001) enhanced some growth parameters of maize above the un-inoculated control. Isolates that showed significant effect on at least two growth parameters were identified at species or genera level. In conclusion, selected diazotrophic isolates may be potentially beneficial but they should be tested more in greenhouse and field conditions with maize to confirm their potential for application as biofertilizers.

  14. Isolation and screening of bacteria for their diazotrophic potential and their influence on growth promotion of maize seedlings in greenhouses

    Directory of Open Access Journals (Sweden)

    Medhin Hadish Kifle

    2016-01-01

    Full Text Available Poor soil fertility is one of the major constraints for crop production. Nitrogen is the most limiting nutrient for increasing crop productivity. Therefore, there is a need to identify diazotrophic inoculants as an alternative or supplement to N-fertilizers for sustainable agriculture. In the current study, a number of free-living diazotrophic bacteria were isolated from soils collected from maize rhizosphere and from leaves and roots of maize within the KwaZulu-Natal Province, Republic of South Africa. Ninety two isolates were selected for further screening because they were able to grow on N-free media containing different carbon sources. Isolates that were very slow to grow on N-free media were discarded. The isolates were screened in vitro for diazotrophic potential tests for ammonia production and acetylene reduction. Ethylene (C2H4 production was quantified and ranged from 4 to 73 nmoles of C2H4 h-1 culture-1. The top twenty isolates were re-screened on maize seedlings, and eight isolates significantly (P=0.001 enhanced some growth parameters of maize above the un-inoculated control. Isolates that showed significant effect on at least two growth parameters were identified at species or genera level. In conclusion, selected diazotrophic isolates may be potentially beneficial but they should be tested more in greenhouse and field conditions with maize to confirm their potential for application as biofertilizers.

  15. Allelopathic effects of aqueous extracts of sunflower on wheat (triticum aestivum l.) and maize (zea mays l.)

    International Nuclear Information System (INIS)

    Muhammad, Z.; Mujeed, A.

    2014-01-01

    Sunflower is a potent allelopathic plant which possesses important allelochemicals with known allelopathic activity on other plants. In this study, allelopathic effects of fresh aqueous extracts (FAE) and air dried aqueous extracts (DAE) of root, shoot and leaves of sunflower (Halianthus annuus L.) were investigated on germination and seedling growth of wheat (Triticum aestivum L.) and maize (Zea mays L.) in seed bioassay experiments carried out at Botany Department of Peshawar University during 2010. Results showed significantly inhibitory effects of aqueous extracts on seed germination, growth and dry biomass of seedlings of wheat and maize. In wheat seedlings, significant germination inhibition (15.21%), increased mean germination time (MGT) (57.76%), reduced plumule and radical growth (21.66 and 28.44%) and lowered seedlings dry biomass (31.05%) were recorded under dry aqueous extracts of leaf when compared to control. Germination percentage of maize was inhibited by dry aqueous extracts of leaf by 7.81%, germination index by 16.51%, increased MGT by 25.53%, decreased plumule and radical lengths by 29.00 and 36.12% respectively, and lowered maize seedling dry biomass by 34.02 %. In both experiments, dry aqueous extracts (DAE) were more phytotoxic than fresh aqueous extracts (FAE). Similarly, inhibitory effects of aqueous extracts of different parts of sunflower were recorded in the order leaf > shoot > root for both tested plants. (author)

  16. Nitrogen fertilizer fate after introducing maize into a continuous paddy rice cropping system

    Science.gov (United States)

    Thiemann, Irabella; He, Yao; Siemens, Jan; Brüggemann, Nicolas; Lehndorf, Eva; Amelung, Wulf

    2017-04-01

    After introducing upland crops into permanent flooded cropping systems, soil conditions temporally change from anaerobic to aerobic, which profoundly impacts nitrogen (N) dynamics. In the framework of the DFG research unit 1701 ICON we applied a single 15N-urea pulse in a field experiment in the Philippines with three different crop rotations: continuous paddy rice, paddy rice-dry rice, and paddy rice-maize. Subsequently, we traced the fate of the labelled urea in bulk soil, rhizosphere, roots, biomass and microbial residues (amino sugars) within the following two years. 15N recovery in the first 5 cm of bulk soil was highest in the first dry season of continuous paddy rice cropping (37.8 % of applied 15N) and lowest in the paddy rice-maize rotation (19.2 %). While an accumulation over time could be observed in bulk soil in 5-20 cm depth of the continuous paddy rice system, the recoveries decreased over time within the following two years in the other cropping systems. Highest 15N-recovery in shoots and roots were found in the continuous paddy rice system in the first dry season (27.3 % in shoots, 3.2 % in roots) as well as in the following wet season (4.2 % in shoots, 0.3 % in roots). Lowest recoveries in biomass were found for the paddy rice-dry rice rotation. Long-term fixation of 15N in microbial biomass residues was observed in all cropping systems (2-3 % in the 3rd dry season). The results indicate that the introduction of maize into a continuous paddy rice cropping system can reduce the fertilizer N use efficiency especially in the first year, most likely due to nitrate leaching and gaseous losses to the atmosphere.

  17. Prone to fix: Resilience of the active nitrogen-fixing rice root microbiome

    Science.gov (United States)

    Hurek, Thomas; Sabale, Mugdha; Sarkar, Abhijit; Pees, Tobias; Reinhold-Hurek, Barbara

    2016-04-01

    Due to water consumption, many lowland rice areas in Asia are undergoing a transition that involves adoption of new management strategies, with crop rotations encompassing a non-flooded crop, including maize. Shifting from flooded to non-flooded cropping is likely to affect microbial nitrogen cycling. For analysis of the root-associated microbiome of rice and maize in response to flooding or nitrogen fertilizer, we combine methods of microbial ecology (Next-Generation sequencing of amplicons), and a reductionist approach with pure cultures of the endophytic diazotroph Azoarus sp.. Field plots of the ICON project (Introducing non-flooded crops in rice-dominated landscapes: Impact on Carbon, nitrogen and water budgets) at the International Rice Research Institute in the Philippines were analyzed. Root-associated activity of nitrogenase gene expression was assessed by quantitative RT-PCR of nifH. For rice, expression levels were surprisingly stable, in response to non-flooded versus flooded conditions, or in response to conventional nitrogen fertilizer applications versus lack of N-fertilizer. In contrast, the active diazotrophic population of maize roots was not resistant to N-fertilization, nifH expression strongly decreased. Concordant changes in the diazotrophic resident or active communities were detected by nifH amplicon sequence analysis, based on bacterial DNA or mRNA, respectively. For high-resolution analyses of the endobiome in gnotobiotic culture, we developed a dual fluorescence reporter system for Azoarcus sp. BH72 which allows to quantify and visualize epi- and endophytic gene expression by concfocal microscopy (CLSM). This allowed us to demonstrate sites of active nitrogen fixation (gene expression) in association with rice roots. We confirmed that at low nitrogen fertilizer levels, endophytic nifH gene expression persisted in rice roots, while it was repressed in maize roots. This supports our observation of remarkable stability of nitrogen fixation

  18. Estimated environmental loads of alpha-amylase from transgenic high-amylase maize

    Energy Technology Data Exchange (ETDEWEB)

    Wolt, Jeffrey D. [Department of Agronomy, Iowa State University, Ames, IA 50011 (United States); Biosafety Institute for Genetically Modified Agricultural Products, 164 Seed Science, Iowa State University, Ames, IA 50011 (United States); Karaman, Sule [Biosafety Institute for Genetically Modified Agricultural Products, 164 Seed Science, Iowa State University, Ames, IA 50011 (United States)

    2007-11-15

    Environmental exposure of plants bioengineered to improve efficiencies of biofuel production is an important consideration for their adoption. High-amylase maize genetically engineered to produce thermostable alpha-amylase in seed endosperm is currently in development, and its successful adoption will entail >1000 km{sup 2} of annual production in the USA. Environmental exposure of thermostable amylase will occur in production fields from preharvest and harvest dropped grain, with minor additional contributions from stover and root biomass. Mass loadings of thermostable alpha-amylase are projected to be 16 kg km{sup -2} and represent a potential source of increased alpha-amylase activity in receiving soils. An understanding of the degradation, persistence, accumulation, and activity of thermostable alpha-amylase introduced from transgenic high-amylase maize will be necessary in order to effectively manage transgenic crop systems intended or biofeedstock production. (author)

  19. Predicting stem borer density in maize using RapidEye data and generalized linear models

    Science.gov (United States)

    Abdel-Rahman, Elfatih M.; Landmann, Tobias; Kyalo, Richard; Ong'amo, George; Mwalusepo, Sizah; Sulieman, Saad; Ru, Bruno Le

    2017-05-01

    Average maize yield in eastern Africa is 2.03 t ha-1 as compared to global average of 6.06 t ha-1 due to biotic and abiotic constraints. Amongst the biotic production constraints in Africa, stem borers are the most injurious. In eastern Africa, maize yield losses due to stem borers are currently estimated between 12% and 21% of the total production. The objective of the present study was to explore the possibility of RapidEye spectral data to assess stem borer larva densities in maize fields in two study sites in Kenya. RapidEye images were acquired for the Bomet (western Kenya) test site on the 9th of December 2014 and on 27th of January 2015, and for Machakos (eastern Kenya) a RapidEye image was acquired on the 3rd of January 2015. Five RapidEye spectral bands as well as 30 spectral vegetation indices (SVIs) were utilized to predict per field maize stem borer larva densities using generalized linear models (GLMs), assuming Poisson ('Po') and negative binomial ('NB') distributions. Root mean square error (RMSE) and ratio prediction to deviation (RPD) statistics were used to assess the models performance using a leave-one-out cross-validation approach. The Zero-inflated NB ('ZINB') models outperformed the 'NB' models and stem borer larva densities could only be predicted during the mid growing season in December and early January in both study sites, respectively (RMSE = 0.69-1.06 and RPD = 8.25-19.57). Overall, all models performed similar when all the 30 SVIs (non-nested) and only the significant (nested) SVIs were used. The models developed could improve decision making regarding controlling maize stem borers within integrated pest management (IPM) interventions.

  20. Efficiency of mineral fertilizers and mucuna on the improvement of the yield of maize in zimbabwe

    International Nuclear Information System (INIS)

    Pieterse, P.J.; Agenbag, G.A.

    2014-01-01

    In Zimbabwe farmers use sub-optimal amounts of fertilizers due to cash limitations and poor access to fertilizer markets, hence the need to integrate legumes like mucuna (Mucuna pruriens) into their cropping systems. In this study, the effect of P and N along with different mucuna management options was investigated on the yield and yield components of maize. The experimental design was a split - split- plot with two P rates (0 and 40 kg P ha/sup -1/) applied to a preceding mucuna crop, four mucuna management options 1) fallow (F), 2) mucuna ploughed in at flowering (MF), 3) all mucuna above ground biomass removed at maturity and only roots were ploughed in (MAR) and 4) mucuna pods removed and the residues ploughed in (MPR 3 and four N treatments (N0 = 0, N1 =40, N2 = 80 and N3 = 120 kg N ha/sup -1/ respectively) applied to a subsequent maize crop. The various crop parameters like grain yield, cob length, number of grains per cob, cob diameter, 1000 dry grain weight, stalk weight and harvest index of maize were determined. Phosphorous application improved mean maize grain yield from 2.29 t ha/sup -1/ to 2.34 t ha/sup -1/. The MF and N3 treatment combination resulted in the highest maize grain yield. The MF and MPR and N0 treatment combinations resulted in similar grain yields when compared with F and MAR management options and N3. Other parameters followed similar trends. The MF and MPR management options could, therefore, save 80 and 120 kg N ha/sup -1/for smallholder farmers without sacrificing yield. (author)

  1. Influence of arbuscular mycorrhizae on photosynthesis and water status of maize plants under salt stress.

    Science.gov (United States)

    Sheng, Min; Tang, Ming; Chen, Hui; Yang, Baowei; Zhang, Fengfeng; Huang, Yanhui

    2008-09-01

    The influence of arbuscular mycorrhizal (AM) fungus Glomus mosseae on characteristics of the growth, water status, chlorophyll concentration, gas exchange, and chlorophyll fluorescence of maize plants under salt stress was studied in the greenhouse. Maize plants were grown in sand and soil mixture with five NaCl levels (0, 0.5, 1.0, 1.5, and 2.0 g/kg dry substrate) for 55 days, following 15 days of non-saline pretreatment. Under salt stress, mycorrhizal maize plants had higher dry weight of shoot and root, higher relative chlorophyll content, better water status (decreased water saturation deficit, increased water use efficiency, and relative water content), higher gas exchange capacity (increased photosynthetic rate, stomatal conductance and transpiration rate, and decreased intercellular CO(2) concentration), higher non-photochemistry efficiency [increased non-photochemical quenching values (NPQ)], and higher photochemistry efficiency [increased the maximum quantum yield in the dark-adapted state (Fv/Fm), the maximum quantum yield in the light-adapted sate (Fv'/Fm'), the actual quantum yield in the light-adapted steady state (phiPSII) and the photochemical quenching values (qP)], compared with non-mycorrhizal maize plants. In addition, AM symbiosis could trigger the regulation of the energy biturcation between photochemical and non-photochemical events reflected in the deexcitation rate constants (kN, kN', kP, and kP'). All the results show that G. mosseae alleviates the deleterious effect of salt stress on plant growth, through improving plant water status, chlorophyll concentration, and photosynthetic capacity, while the influence of AM symbiosis on photosynthetic capacity of maize plants can be indirectly affected by soil salinity and mycorrhizae-mediated enhancement of water status, but not by the mycorrhizae-mediated enhancement of chlorophyll concentration and plant biomass.

  2. Silicon induced improvement in morpho-physiological traits of maize (zea mays l.) under water deficit

    International Nuclear Information System (INIS)

    Amin, M.; Ahmad, R.; Basra, S.M.A.; Murtaza, G.

    2014-01-01

    Current water scarcity is an emerging issue in semi-arid regions like Pakistan and cause of deterioration in productivity of crops to reduce crop yield all over the world. Silicon is known to be better against the deleterious effects of drought on plant growth and development. A pot study was conducted to evaluate the effect of Si nutrition (0, 50, 100 and 150 mg/kg) on the growth of a relatively drought tolerant (P-33H25) and sensitive (FH-810) maize hybrids. Two levels of soil water content were used viz. 100 and 60% of field capacity. Water deficit condition in soil significantly reduced morphological and physiological attributes of maize plants. Silicon application significantly improved the plant height, leaf area per plant, primary root length, dry matter of shoot and roots and plant dry matter, water relation and gas exchange characteristics of both maize cultivars under water deficit condition. Poor growth of drought stressed plants was significantly improved with Si application. The silicon fertilized (100 mg/kg) drought stressed plants of hybrid P-33H25 produced maximum (21.68% more) plant dry matter as compared to plants that were not provided with silicon nutrition. Nonetheless, silicon application (150 mg/kg) resulted in maximum increase (26.03%) in plant dry weight of hybrid FH-810 plants that were grown under limited moisture supply i.e., 60% FC. In conclusion silicon application to drought stressed maize plants was better to improve the growth and dry matter could be attributed to improved osmotic adjustment, photosynthetic rate and lowered transpiration. (author)

  3. EFFECT OF ALUMINUM ON PLANT GROWTH, PHOSPORUS AND CALCIUM UPTAKE OF TROPICAL RICE (Oryza sativa, MAIZE (Zea mays, AND SOYBEAN (Glycine max

    Directory of Open Access Journals (Sweden)

    D. Nursyamsi

    2018-01-01

    Full Text Available Aluminum toxicity is the most limiting factor to plant growth on acid soils. Structural and functional damages in the root system by Al decrease nutrient uptake and lead to reduce plant growth and mineral deficiency in shoot. Greenhouse experiment was conducted to study the effect of Al on plant growth, and P and Ca uptake of rice, maize, and soybean. The plants were grown in hydroponic solution added with 0, 5, 10, and 30 ppm Al, at pH 4.0. The results showed that relative growth of shoots and roots of upland rice, lowland rice, maize, and soybean decreased with an increase of Al level. However, sometimes the low Al level (5 ppm stimulated shoot and root growth of some varieties in these species. According to total AlRG30 values, which is Al concentration in solution when relative growth decreased to 50%, Al tolerance of species was in order of barley < maize < soybean < lowland rice < upland rice. For maize, Al tolerance was in the order of Arjuna < Kalingga < P 3540 < SA 5 < SA 4 < PM 95 A < SA 3 < Antasena; for soybean was Wilis < INPS < Galunggung < Kerinci < Kitamusume; for lowland rice was RD 23 < Kapuas < Cisadane < KDML 105 < IR 66 < RD 13, and for upland rice was Dodokan < JAC165 < Cirata < Orizyca sabana 6 < Danau Tempe < Laut Tawar. Based on the rank of Al tolerance, rice was the useful crop to be planted in acid soils. Antasena (maize, Kitamusume ( soybean , RD 13 (lowland rice, and Laut Tawar (upland rice were also recommended for acid soils. P and Ca concentration in shoots and roots commonly decreased with an increase of Al level. However, the low Al level stimulated absorption of P and Ca concentrations in shoots and roots.

  4. The distribution of 137Cs in maize (Zea mays L.) and two millet species (Panicum miliaceum L. and Panicum maximum Jacq.) cultivated on the cesium-contaminated soil

    International Nuclear Information System (INIS)

    Bystrzejewska-Nowacka, G.; Nowacka, R.

    2004-01-01

    The plant of three species (Zea mays L., Panicum miliaceum L. and Panicum maximum Jacq.) were grown on the soil contaminated with 0.3 mM CsCl solution traced with 137 Cs, in greenhouse. For all the species, the fresh-to-dry weight ratio was equal in the cesium-treated plants and in the central group after 3 weeks of culture. The shoot-to root fresh weight and dry weight ratios were decreased in maize, unchanged in Panicum miliaceum and increased in Panicum maximum, comparing to the control without cesium treatment. The shoot/soil and also root/soil transfer (TF) for 137 Cs (measured by means of Na I gamma spectrometer) were always the highest in maize, then lower in Panicum miliaceum and the lowest in Panicum maximum. All the plants seem to be hyperaccumulators of cesium. The root/soil Tf was especially high in maize, i.e. 55 (kBq kg -1 biomass)/kBq Kg -1 soil). The shoot/root concentration factor (CF) for 137 Cs was the lowest in maize, higher in Panicum miliaceum and highest in Panicum maximum. The proved ability of the investigated plants for phytoextraction of the soil cesium points to the (author). The detectability and reliin soil bioremediation. From this point of view, Panicum maximum seems to be the most useful plant because it accumulates cesium mainly in the shoot, and maize would be the least useful spices since it has the highest accumulation in root. (author)

  5. Maize cob losses and their effects on the poverty status of maize

    African Journals Online (AJOL)

    This study analysed fresh maize cob losses and its effect on the poverty status of maize farmers in Edo State,. Nigeria. The specific .... is the poverty gap for ... Total cost. 162,367.48. 100.00. Returns. Total expected yield (N). 327,966.63. _.

  6. Identification of resistance to Maize rayado fino virus in maize inbred lines

    Science.gov (United States)

    Maize rayado fino virus (MRFV) is one of the most important virus diseases of maize in America. Severe yield losses, ranging from 10 to 50% in landraces to nearly 100% in contemporary cultivars, have been reported. Resistance has been reported in populations, but few inbred lines have been identifie...

  7. Colonization of Plant Growth Promoting Rhizobacteria (PGPR) on Two Different Root Systems

    International Nuclear Information System (INIS)

    Chaudhry, M. Z.; Naz, A. U.; Nawaz, A.; Nawaz, A.; Mukhtar, H.

    2016-01-01

    Phytohormones producing bacteria enhance the plants growth by positively affecting growth of the root. Plant growth promoting bacteria (PGPR) must colonize the plant roots to contribute to the plant's endogenous pool of phytohormones. Colonization of these plant growth promoting rhizobacteria isolated from rhizosplane and soil of different crops was evaluated on different root types to establish if the mechanism of host specificity exist. The bacteria were isolated from maize, wheat, rice, canola and cotton and phytohormone production was detected and quantified by HPLC. Bacteria were inoculated on surface sterilized seeds of different crops and seeds were germinated. After 7 days the bacteria were re-isolated from the roots and the effect of these bacteria was observed by measuring increase in root length. Bacteria isolated from one plant family (monocots) having fibrous root performed well on similar root system and failed to give significant results on other roots (tap root) of dicots. Some aggressive strains were able to colonize both root systems. The plant growth promoting activities of the bacteria were optimum on the same plant from whom roots they were isolated. The results suggest that bacteria adapt to the root they naturally inhabit and colonize the same plant root systems preferably. Although the observe trend indicate host specificity but some bacteria were aggressive colonizers which grew on all the plants used in experiment. (author)

  8. Toxin distribution and sphingoid base imbalances in Fusarium verticillioides-infected and fumonisin B1-watered maize seedlings.

    Science.gov (United States)

    Arias, Silvina L; Mary, Verónica S; Otaiza, Santiago N; Wunderlin, Daniel A; Rubinstein, Héctor R; Theumer, Martín G

    2016-05-01

    Fusarium verticillioides is a major maize pathogen and there are susceptible and resistant cultivars to this fungal infection. Recent studies suggest that its main mycotoxin fumonisin B1 (FB1) may be involved in phytopathogenicity, but the underlying mechanisms are mostly still unknown. This work was aimed at assessing whether FB1 disseminates inside the plants, as well as identifying possible correlations between the maize resistant/susceptible phenotype and the unbalances of the FB1-structurally-related sphingoid base sphinganine (Sa) and phytosphingosine (Pso) due to toxin accumulation. Resistant (RH) and susceptible hybrid (SH) maize seedlings grown from seeds inoculated with a FB1-producer F. verticillioides and from uninoculated ones irrigated with FB1 (20 ppm), were harvested at 7, 14 and 21 days after planting (dap), and the FB1, Sa and Pso levels were quantified in roots and aerial parts. The toxin was detected in roots and aerial parts for inoculated and FB1-irrigated plants of both hybrids. However, FB1 levels were overall higher in SH seedlings regardless of the treatment (infection or watering). Sa levels increased substantially in RH lines, peaking at 54-fold in infected roots at 14 dap. In contrast, the main change observed in SH seedlings was an increase of Pso in infected roots at 7 dap. Here, it was found that FB1 disseminates inside seedlings in the absence of FB1-producer fungal infections, perhaps indicating this might condition the fungus-plant interaction before the first contact. Furthermore, the results strongly suggest the existence of at least two ceramide synthase isoforms in maize with different substrate specificities, whose differential expression after FB1 exposure could be closely related to the susceptibility/resistance to F. verticillioides. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. 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.

  10. Pigeon Pea and Cowpea-Based Cropping Systems Improve Vesicular Arbuscular Mycorrhizal Fungal Colonisation of Subsequent Maize on the Alfisols in Central Malawi

    Directory of Open Access Journals (Sweden)

    Keston O. W. Njira

    2017-01-01

    Full Text Available Mycorrhizal associations contribute to the sustainability of crop production systems through their roles in nutrient cycling and other benefits in the soil-plant ecosystems. A two-year study was conducted on the Alfisols of Lilongwe and Dowa districts, Central Malawi, to assess the vesicular-arbuscular mycorrhizal (VAM fungal colonisation levels in pigeon pea, cowpea, and maize grown in sole cropping, legume-cereal, and legume-legume intercropping systems and in the maize grown in short rotation (year 2 as influenced by the previous cropping systems and N fertilizer application. The gridline intersect method was used to assess the VAM fungal colonisation levels. Results showed that all treatments that included legumes whether grown as sole crop, in legume-cereal or in legume-legume cropping systems in the previous year, had significantly higher (P < 0.05 VAM fungal colonisation of the rotational maize crop roots by a range 39% to 50% and 19% to 47% than those in maize supplied and not supplied with N fertilizer, respectively, in a maize-maize short rotation, at the Lilongwe site. A similar trend was reported for the Dowa site. Furthermore, there were positive correlations between VAM fungal colonisation and the plant P content, dry matter yield, and nodule numbers. Further studies may help to assess the diversity of VAM fungal species in Malawi soils and identify more adaptive ones for inoculation studies.

  11. Exploring karyotype diversity of Argentinian Guaraní maize landraces: Relationship among South American maize.

    Directory of Open Access Journals (Sweden)

    María Florencia Realini

    Full Text Available In Argentina there are two different centers of maize diversity, the Northeastern (NEA and the Northwestern (NWA regions of the country. In NEA, morphological studies identified 15 landraces cultivated by the Guaraní communities in Misiones Province. In the present study we analyzed the karyotype diversity of 20 populations of Guaraní maize landraces through classical and molecular cytogenetic analyses. Our results demonstrate significant intra and inter-populational variation in the percentage, number, size, chromosome position and frequencies of the heterochromatic blocks, which are called knobs. Knob sequence analysis (180-bp and TR-1 did not show significant differences among Guaraní populations. B chromosomes were not detected, and abnormal 10 (AB10 chromosomes were found with low frequency (0.1≥f ≤0.40 in six populations. Our results allowed karyotypic characterization of each analyzed population, defining for the first time the chromosomal constitution of maize germplasm from NEA. The multivariate analysis (PCoA and UPGMA of karyotype parameters allowed the distinction between two populations groups: the Popcorn and the Floury maize populations. These results are in agreement with previously published microsatellite and morphological/phenological studies. Finally, we compared our karyotype results with those previously reported for NWA and Central Region of South America maize. Our data suggest that there are important differences between maize from NEA and NWA at the karyotype level, supporting the hypothesis that there are two pathways of input of South America maize. Our results also confirm the existence of two centers of diversification of Argentinian native maize, NWA and NEA. This work contributes new knowledge about maize diversity, which is relevant for future plans to improve commercial maize, and for conservation of agrobiodiversity.

  12. 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)

  13. 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...

  14. Locally processed roasted-maize-based weaning foods fortified with ...

    African Journals Online (AJOL)

    Locally processed roasted-maize-based weaning foods fortified with legumes: factors ... African Journal of Food, Agriculture, Nutrition and Development ... Tom Brown (roasted-maize porridge) is one of the traditional weaning foods in Ghana.

  15. Aflatoxin variations in maize flour and grains collected from various ...

    African Journals Online (AJOL)

    In Kenya, maize remains an important staple food in every household. ... upper limit is 10ppb, indicating good manufacturing practices (GMP) by the millers. ... In summary, the study found aflatoxin contamination in maize grains especially in ...

  16. the influence of farmers' adoption behaviour on maize production ...

    African Journals Online (AJOL)

    p2333147

    The main cash crops grown in the country include coffee, sisal, cashew, cotton, tobacco ... Among these food crops, maize is the most important cereal food crop, and ... promoting recommended maize production practices in a package form.

  17. Diversity in global maize germplasm: Characterization and utilization

    Indian Academy of Sciences (India)

    2012-10-15

    Oct 15, 2012 ... maize farmers as well as to the scientific community are depicted in figure 1, and ..... best practices for maintaining the original genetic diversity of the gene bank ..... maize; in Studies in the neolithic and urban revolution: V.

  18. Importance of husk covering on field infestation of maize by ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-10-20

    Oct 20, 2008 ... An experiment was conducted to determine the importance of husk covering on field infestation of maize by the maize ... high yielding plants with no consideration for resistance ..... provided financial support for the study.

  19. Factors Affecting the Efficiency of Maize Marketing in Vandeikya ...

    African Journals Online (AJOL)

    Factors Affecting the Efficiency of Maize Marketing in Vandeikya Local Government Area of Benue State, Nigeria. ... Two hundred maize marketers were selected from Vandeikya Local Area (LGA) of ... EMAIL FULL TEXT EMAIL FULL TEXT

  20. participatory evaluation of drought tolerant maize varieties in the ...

    African Journals Online (AJOL)

    User

    ). Maize production provides livelihoods for millions of subsistence farmers in WCA, thus, increasing the productivity of maize-based cropping sys- tems could increase and stabilize rural incomes, alleviate poverty and reduce food insecurity in.

  1. Leaf transpiration efficiency of some drought-resistant maize lines

    Science.gov (United States)

    Field measurements of leaf gas exchange in maize often indicate stomatal conductances higher than required to provide substomatal carbon dioxide concentrations saturating to photosynthesis. Thus maize leaves often operate at lower transpiration efficiency (TE) than potentially achievable for specie...

  2. Fusarium diseases of maize associated with mycotoxin contamination of agricultural products intended to be used for food and feed.

    Science.gov (United States)

    Oldenburg, Elisabeth; Höppner, Frank; Ellner, Frank; Weinert, Joachim

    2017-08-01

    Infections of maize with phytopathogenic and toxinogenic Fusarium spp. may occur throughout the cultivation period. This can cause different types of diseases in vegetative and generative organs of the plant. Along with these infections, mycotoxins are often produced and accumulated in affected tissues, which could pose a significant risk on human and animal health when entering the food and feed chain. Most important fungal species infecting European maize belong to the Fusarium sections Discolour and Liseola, the first being more prevalent in cooler and humid climate regions than the second predominating in warmer and dryer areas. Coexistence of several Fusarium spp. pathogens in growing maize under field conditions is the usual case and may lead to multi-contamination with mycotoxins like trichothecenes, zearalenone and fumonisins. The pathways how the fungi gain access to the target organs of the plant are extensively described in relation to specific symptoms of typical rot diseases regarding ears, kernels, rudimentary ears, roots, stem, leaves, seed and seedlings. Both Gibberella and Fusarium ear rots are of major importance in affecting the toxinogenic quality of grain or ear-based products as well as forage maize used for human or animal nutrition. Although rudimentary ears may contain high amounts of Fusarium toxins, the contribution to the contamination of forage maize is minor due to their small proportion on the whole plant dry matter yield. The impact of foliar diseases on forage maize contamination is regarded to be low, as Fusarium infections are restricted to some parts on the leaf sheaths and husks. Mycotoxins produced in rotted basal part of the stem may contribute to forage maize contamination, but usually remain in the stubbles after harvest. As the probability of a more severe disease progression is increasing with a prolonged cultivation period, maize should be harvested at the appropriate maturity stage to keep Fusarium toxin contamination as

  3. VIGOR TESTS ASSOCIATION AS AN ALTERNATIVE FOR PRECISE AND EFFICIENT ASSESSMENT OF MAIZE SEED QUALITY

    Directory of Open Access Journals (Sweden)

    MARCOS ALTOMANI NEVES DIAS

    2015-01-01

    Full Text Available This study aimed to associate two concepts of seed vigor testing, the aging and seedling growth using image analysis, providing a feasible and time-saving way to evaluate maize seed vigor in large scale. For this purpose, five seed lots with different vigor levels from two single hybrids were used. The seeds were characterized by moisture content, germination, seedling emergence, seedling emergence speed index, accelerated aging and cold tests. The treatments were composed by varying the accelerated aging periods (0, 24, 48, 72 and 96h and seedling growth periods (48 and 72h, before submitting the seedlings to image analysis for seedling root length measurement. Considering the results obtained, the adaptation of accelerated aging test by reducing the aging duration from 96h to 48h, and the replacement of the germination test by seedling root length measurement using image analysis could be considered a potential tool for maize seed vigor assessment. The treatments composed of 48h of seed aging followed by seedlings root length measurements using image analysis provided reliable data, compared to traditional vigor tests and it could be considered an efficient and timesaving approach, associating two different concepts of seed vigor analysis.

  4. Molecular adaptations of Herbaspirillum seropedicae during colonization of the maize rhizosphere.

    Science.gov (United States)

    Balsanelli, Eduardo; Tadra-Sfeir, Michelle Z; Faoro, Helisson; Pankievicz, Vânia Cs; de Baura, Valter A; Pedrosa, Fábio O; de Souza, Emanuel M; Dixon, Ray; Monteiro, Rose A

    2016-09-01

    Molecular mechanisms of plant recognition and colonization by diazotrophic bacteria are barely understood. Herbaspirillum seropedicae is a Betaproteobacterium capable of colonizing epiphytically and endophytically commercial grasses, to promote plant growth. In this study, we utilized RNA-seq to compare the transcriptional profiles of planktonic and maize root-attached H. seropedicae SmR1 recovered 1 and 3 days after inoculation. The results indicated that nitrogen metabolism was strongly activated in the rhizosphere and polyhydroxybutyrate storage was mobilized in order to assist the survival of H. seropedicae during the early stages of colonization. Epiphytic cells showed altered transcription levels of several genes associated with polysaccharide biosynthesis, peptidoglycan turnover and outer membrane protein biosynthesis, suggesting reorganization of cell wall envelope components. Specific methyl-accepting chemotaxis proteins and two-component systems were differentially expressed between populations over time, suggesting deployment of an extensive bacterial sensory system for adaptation to the plant environment. An insertion mutation inactivating a methyl-accepting chemosensor induced in planktonic bacteria, decreased chemotaxis towards the plant and attachment to roots. In summary, analysis of mutant strains combined with transcript profiling revealed several molecular adaptations that enable H. seropedicae to sense the plant environment, attach to the root surface and survive during the early stages of maize colonization. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  5. Strategic Marketing Problems in the Uganda Maize Seed Industry

    OpenAIRE

    Larson, Donald W.; Mbowa, Swaibu

    2004-01-01

    Strategic marketing issues and challenges face maize seed marketing firms as farmers increasingly adopt hybrid varieties in a modernizing third world country such as Uganda. The maize seed industry of Uganda has changed dramatically from a government owned, controlled, and operated industry to a competitive market oriented industry with substantial private firm investment and participation. The new maize seed industry is young, dynamic, growing and very competitive. The small maize seed marke...

  6. Effect of arbuscular mycorrhizal fungus (Glomus caledonium) on the accumulation and metabolism of atrazine in maize (Zea mays L.) and atrazine dissipation in soil

    Energy Technology Data Exchange (ETDEWEB)

    Huang Honglin [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, 18th Shuangqinglu, Haidian District, Beijing 100085 (China); Zhang Shuzhen [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, 18th Shuangqinglu, Haidian District, Beijing 100085 (China)]. E-mail: szzhang@mail.rcees.ac.cn; Shan Xiaoquan [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, 18th Shuangqinglu, Haidian District, Beijing 100085 (China); Chen Baodong [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, 18th Shuangqinglu, Haidian District, Beijing 100085 (China); Zhu Yongguan [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, 18th Shuangqinglu, Haidian District, Beijing 100085 (China); Bell, J. Nigel B. [Center for Environmental Policy, Imperial College, London (United Kingdom)

    2007-03-15

    Effects of an arbuscular mycorrhizal (AM) fungus (Glomus caledonium) on accumulation and metabolism of atrazine in maize grown in soil contaminated with different concentrations of atrazine were investigated in a series of pot experiments. Roots of mycorrhizal plants accumulated more atrazine than non-mycorrhizal roots. In contrast, atrazine accumulation in shoot decreased in mycorrhizal compared with non-mycorrhizal plants. No atrazine derivatives were detected in the soil, either with or without mycorrhizal colonization. However, atrazine metabolites, deethylatrazine (DEA) and deisopropylatrazine (DIA), were detected in plant roots and the AM colonization enhanced the metabolism. After plant harvest atrazine concentrations decreased markedly in the soils compared to the initial concentrations. The decreases were the most in rhizosphere soil and then near-rhizosphere soil and the least in bulk soil. Mycorrhizal treatment enhanced atrazine dissipation in the near-rhizosphere and bulk soils irrespective of atrazine application rates. - Arbuscular mycorrhizal fungus increases the accumulation and metabolism of atrazine in maize.

  7. Effect of arbuscular mycorrhizal fungus (Glomus caledonium) on the accumulation and metabolism of atrazine in maize (Zea mays L.) and atrazine dissipation in soil

    International Nuclear Information System (INIS)

    Huang Honglin; Zhang Shuzhen; Shan Xiaoquan; Chen Baodong; Zhu Yongguan; Bell, J. Nigel B.

    2007-01-01

    Effects of an arbuscular mycorrhizal (AM) fungus (Glomus caledonium) on accumulation and metabolism of atrazine in maize grown in soil contaminated with different concentrations of atrazine were investigated in a series of pot experiments. Roots of mycorrhizal plants accumulated more atrazine than non-mycorrhizal roots. In contrast, atrazine accumulation in shoot decreased in mycorrhizal compared with non-mycorrhizal plants. No atrazine derivatives were detected in the soil, either with or without mycorrhizal colonization. However, atrazine metabolites, deethylatrazine (DEA) and deisopropylatrazine (DIA), were detected in plant roots and the AM colonization enhanced the metabolism. After plant harvest atrazine concentrations decreased markedly in the soils compared to the initial concentrations. The decreases were the most in rhizosphere soil and then near-rhizosphere soil and the least in bulk soil. Mycorrhizal treatment enhanced atrazine dissipation in the near-rhizosphere and bulk soils irrespective of atrazine application rates. - Arbuscular mycorrhizal fungus increases the accumulation and metabolism of atrazine in maize

  8. Effect of salicylic acid on physiological and biochemical characterization of maize grown in saline area

    International Nuclear Information System (INIS)

    Fahad, S.; Bano, A.

    2012-01-01

    The aim of the present investigation was to determine the effect of exogenously applied salicylic acid (SA) on physiology of maize (Zea mays L.) hybrid cv. 3025 grown in saline field (pH 8.4 and EC 4.2 ds/m) as well as on the nutrient status of saline soil. The salicylic acid (10/sup -5/M) was applied as foliar spray, 40 days after sowing (DAS) at vegetative stage of maize plants. The salinity significantly increased sugar contents, protein, proline and superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APOX) activities but the chlorophyll, carotenoid contents, osmotic potential and membrane stability index (MSI) were lower than the control. Foliar application of salicylic acid (SA) to salt stressed plants further augmented the sugar, protein, proline, superoxide dismutase (SOD), peroxidase (POD) ascorbate peroxidase (APOX) activities, endogenous abscisic acid (ABA) , indole acetic acid (IAA) content, and root length, fresh and dry weights of roots whereas, the chlorophyll a/b and ABA/IAA ratio were decreased. The exogenous application of SA significantly decreased the Na/sup +/, Ni/sup +3/, Pb/sup +4/, Zn/sup +2/, and Na/sup +//K/sup +/ content of soil and roots while increased the Co/sup +3/, Mn/sup +2/, Cu/sup +3/, Fe/sup +2/, K/sup +/ and Mg/sup +2/ content under salinity stress. It can be inferred that exogenous application of SA (10/sup -5/M) was effective in ameliorating the adverse effects of salinity on nutrient status of soil. SA (10/sup -5/M) can be implicated to mitigate the adverse effects of salinity on maize plants. (author)

  9. Nitrogen effects on maize yield following groundnut in rotation on ...

    African Journals Online (AJOL)

    Rotating maize (Zea mays L.) with groundnut (Arachis hypogaea L.) has been proposed as a way to maintain soil fertility and prevent maize productivity declines in the smallholder cropping systems of sub-humid Zimbabwe. Field experiments with fertilizer-N on maize in rotation with groundnut were conducted at three ...

  10. Intercropping maize with cassava or cowpea in Ghana | Ennin ...

    African Journals Online (AJOL)

    Maize/cassava and maize/cowpea intercrops were evaluated in southern Ghana, over a 5-year period to determine the optimum combination of component crop varieties and component plant population densities to optimize productivity of maize-based intercropping systems. Results indicated that some cowpea varieties ...

  11. The economic implication of substituting cocoa pod husk for maize ...

    African Journals Online (AJOL)

    This saving was found to bridge the deficit between demand and supply as given by supplementation done by importing maize. The study concluded that by utilizing CPH in compounding various livestock feed rations, the high price of maize arising from excessive demand can be reduced. The limiting role of maize in ...

  12. Developing a database for maize variety in Nigeria | Daniel | Moor ...

    African Journals Online (AJOL)

    Performance data of maize varieties at different locations needs to be accurate and accessible to stimulate the improvement of the Nigerian maize seed system. This paper describes a database model to implement a simple computerized information system for maize varieties and their performance at various locations in ...

  13. Review: Maize research and production in Nigeria | Iken | African ...

    African Journals Online (AJOL)

    Maize (Zea mays) is a major important cereal being cultivated in the rainforest and the derived Savannah zones of Nigeria. Land races, improved high yielding and pest and diseases resistant varieties of maize have been developed. Key words: Maize, Zea mays, Nigeria. African Journal of Biotechnology Vol.3(6) 2004: 302- ...

  14. quixotic coupling between irrigation system and maize-cowpea

    African Journals Online (AJOL)

    ACSS

    number row-1 and maize grain yield, respectively. The ridge ... Key Words: Furrow irrigation, water use efficiency, Zea mays. RÉSUMÉ ... important in arid and semi-arid regions, with ... as maize) canopy is not able to intercept all the solar radiation during the growth period. ... Intercropping maize and legumes considerably ...

  15. Quantitative trait loci for resistance to Maize rayado fino virus

    Science.gov (United States)

    Maize rayado fino virus (MRFV) causes one of the most important virus diseases of maize in regions of Mexico, Central and South America, where it causes moderate to severe yield losses. The virus is found from the southern United States. to northern Argentina where its vector, the maize leafhopper D...

  16. Oven-drying reduces ruminal starch degradation in maize kernels

    NARCIS (Netherlands)

    Ali, M.; Cone, J.W.; Hendriks, W.H.; Struik, P.C.

    2014-01-01

    The degradation of starch largely determines the feeding value of maize (Zea mays L.) for dairy cows. Normally, maize kernels are dried and ground before chemical analysis and determining degradation characteristics, whereas cows eat and digest fresh material. Drying the moist maize kernels

  17. Mixed cropping of groundnuts and maize in East Java

    NARCIS (Netherlands)

    Hoof, van W.C.H.

    1987-01-01

    Mixed cropping of groundnuts and maize in East Java was studied by means of a survey of farming practice and by field experiments. The influence of different sowing times and plant density of maize on the development and yield of groundnuts and maize were the main topics in this thesis. Plant

  18. Maize and the Malnutrition Conundrum in South Africa | BOOYENS ...

    African Journals Online (AJOL)

    In this paper, the author gives an overview of the factors leading to maize becoming a staple food among black people in South Africa. The purported relationship between maize consumption and malnutrition, proposals as well as experimental and practical efforts to correct the dietary deficiencies of maize are briefly ...

  19. Selection and Evaluation of Maize Genotypes Tolerance to Low Phosphorus Soils

    Energy Technology Data Exchange (ETDEWEB)

    Yang, J. C.; Jiang, H. M.; Zhang, J. F.; Li, L. L.; Li, G. H. [Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing (China)

    2013-11-15

    Maize species differ in their ability to take up phosphorus (P) from the soil, and these differences are attributed to the morphology and physiology of plants relative to their germplasm base. An effective method of increasing P efficiency in maize is to select and evaluate genotypes that can produce a high yield under P deficient conditions. In this study, 116 maize inbred lines with various genetic backgrounds collected from several Agricultural Universities and Institutes in China were evaluated in a field experiment to identify genotypic differences in P efficiency in 2007. Overall, 15 maize inbred lines were selected from the 116 inbred lines during the 5-year field experimental period based on their 100-grain weight in P-deficient soil at maturity, when compared to the characteristics exhibited in P-sufficient soil. All of the selected lines were evaluated in field experiments from 2008 to 2010 for their tolerance to low-P at the seedling and maturity stages. Inhibition (%) was used and defined as the parameter measured under P limitation compared to the parameters measured under P sufficiency to evaluate the genotypic variation in tolerance. Inhibition of root length, root surface area, volume, root: shoot ratio and P uptake efficiency could be used as indices to assess the genotypic tolerance to P limitation. Low-P tolerant genotypes could uptake more P and accumulate more dry matter at the seedling stage. A strong relationship between the total biomass and root length was exhibited. In order to understand the mechanisms of the genotypic tolerance to low-P soil to utilize P from the sparing soluble P forms, 5 maize genotypes selected out of the 15 maize inbred lines, according to the four quadrant distribution, was used as the criteria in a {sup 32}P isotope tracer experiment to follow the recovery of {sup 32}P in soil P fractions. The {sup 32}P tracer results showed a higher rate for water- soluble P transformation to slowly available P in P deficient soil

  20. Effect of zinc and phosphorus on dry matter yield, uptake and utilization of 65Zn on Maize (Zea Mays L.) grown in a molli-soil

    International Nuclear Information System (INIS)

    Joshi, Megha; Shri Ram; Joshi, G.C.

    2013-01-01

    Zinc uptake and its utilization by Maize (Zea mays L.) variety Pragati using radiotracer 65 Zn technique along with varying levels of phosphorus treatments on dry matter yield was studied. The gamma activity was measured by calibrated NaI(Tl) gamma ray spectrometer. It was observed that zinc uptake in treatment T 2 found to be higher. However, treatment T 6 showed good growth parameters and dry matter yield. The 65 Zn activity was found maximum in roots and minimum in the leaves of maize plant. (author)

  1. The transition from a maternal to external nitrogen source in maize seedlings

    KAUST Repository

    Sabermanesh, Kasra

    2017-02-07

    Maximising NO3 - uptake during seedling development is important as it has a major influence on plant growth and yield. However, little is known about the processes leading to, and involved in, the initiation of root NO3 - uptake capacity in developing seedlings. This study examines the physiological processes involved in root NO3 - uptake and metabolism, to gain an understanding of how the NO3 - uptake system responds to meet demand as maize seedlings transition from seed N use to external N capture. The concentrations of seed-derived free amino acids within root and shoot tissues are initially high, but decrease rapidly until stabilising eight days after imbibition (DAI). Similarly, shoot N% decreases, but does not stabilise until 12-13 DAI. Following the decrease in free amino acid concentrations, root NO3 - uptake capacity increases until shoot N% stabilises. The increase in root NO3 uptake capacity corresponds with a rapid rise in transcript levels of putative NO3 - transporters, ZmNRT2.1 and ZmNRT2.2. The processes underlying the increase in root NO3 - uptake capacity to meet N demand provide an insight into the processes controlling N uptake.

  2. Maize production in mid hills of Nepal: from food to feed security

    OpenAIRE

    Krishna Prasad Timsina; Yuga Nath Ghimire; Jeevan Lamichhane

    2016-01-01

    This study was undertaken in 2016 to analyze the production and utilization of maize in Nepal. Sixty maize growers from Kavre and Lamjung districts were selected using purposive, cluster and simple random sampling techniques. Similarly, six feed industries and five maize experts from Chitwan district were also interviewed. Study shows 56% of the total areas were used for maize production and 50% of the maize areas were covered by hybrid maize. There was no practice of contract maize productio...

  3. Effect of salicylic acid on the growth photosynthesis and carbohydrate metabolism in salt stressed maize plants

    International Nuclear Information System (INIS)

    Moussa, H.R.; Khodary, S.E.A.

    2003-01-01

    Aqueous solutions of salicylic acid as a spray to Na CI-treated corn (Zea mays L,) significantly increased the growth of shoots and roots as measured after seven days of treatment. Spraying of salicylic acid caused significant increases in the activity of both ribulose 1,5 bisphosphate carboxylase (rubisco) enzyme and photosynthetic pigments. Moreover, salicylic acid treatment induced high values of soluble carbohydrate fractions in salt stressed plants as compared with salicylic acid treated samples. These data suggest that salicylic acid might improve the growth pattern of NaCl-treated maize plants via increasing the rate of photosynthesis and carbohydrate metabolism

  4. Rapid screening for aluminum tolerance in maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Carlos Daniel Giaveno

    2000-12-01

    Full Text Available A significant decrease in maize grain yield due to aluminum toxicity is considered to be one of the most important agricultural problems for tropical regions. Genetic improvement is a useful approach to increase maize yield in acid soils, but this requires a rapid and reliable method to discriminate between genotypes. In our work we investigated the feasibility of using hematoxylin staining (HS to detect Al-tolerant plants at the seedling stage. The original population along with two populations obtained after one cycle of divergent selection were evaluated by net root growth (NRG and HS after 7 days in nutrient solution. Results showed a negative correlation between NRG and HS in all populations, in which sensitive plants, characterized by low NRG, exhibited more intense staining than tolerant plants. These results indicate that HS is a useful procedure for selecting Al-tolerant maize seedlings.A importante diminuição nos rendimentos de milho causados pela toxidez produzida pelo alumínio é considerada um dos mais importantes problemas nas regiões tropicais. O melhoramento genético é uma metodologia útil para aumentar os rendimentos do milho em solos ácidos, requerendo um método rápido e seguro que permita diferenciar os diferentes genótipos. O objetivo deste trabalho foi avaliar a possibilidade de utilizar a técnica da coloração com hematoxilina (HS na detecção de plântulas tolerantes ao alumínio. Duas populações obtidas de um ciclo de seleção divergente e a original, foram avaliadas depois de sete dias em solução nutritiva utilizando os parâmetros NRG (crescimento líquido da raiz principal e HS. Os resultados apresentaram uma correlação negativa entre NRG e HS em todas as populações devido ao fato de que as plântulas suscetíveis, caracterizadas por um baixo NRG, apresentaram uma coloração mais intensa do que as tolerantes. Nossos resultados permitem concluir que a técnica de coloração com hematoxilina

  5. Maize lethal necrosis (MLN), an emerging threat to maize-based food security in sub-Saharan Africa

    Science.gov (United States)

    In sub-Saharan Africa, maize is a staple food and key determinant of food security for smallholder farming communities. Pest and disease outbreaks are key constraints to maize productivity. In September 2011, a serious disease outbreak, later diagnosed as maize lethal necrosis (MLN), was reported on...

  6. System of Antioxidant Protection of Corn Roots in Case of Adaptation to Combined Action of Herbicides and Soil Drought

    Directory of Open Access Journals (Sweden)

    G. S. Rossihina

    2005-09-01

    Full Text Available Reaction of antioxidant enzymes in the maize root (Kadr 267 MVhybrid to the combined action of herbicides and soil drought was studied. These conditions activated superoxide dismutase (SOD and peroxidase and coused oscillation in the catalase enzymatic activity.

  7. MaizeGDB: The Maize Model Organism Database for Basic, Translational, and Applied Research

    OpenAIRE

    Lawrence, Carolyn J.; Harper, Lisa C.; Schaeffer, Mary L.; Sen, Taner Z.; Seigfried, Trent E.; Campbell, Darwin A.

    2008-01-01

    In 2001 maize became the number one production crop in the world with the Food and Agriculture Organization of the United Nations reporting over 614 million tonnes produced. Its success is due to the high productivity per acre in tandem with a wide variety of commercial uses. Not only is maize an excellent source of food, feed, and fuel, but also its by-products are used in the production of various commercial products. Maize's unparalleled success in agriculture stems from basic research, th...

  8. A comparison of cellulosic fuel yields and separated soil-surface CO2 fluxes in maize and prairie biofuel cropping systems

    Science.gov (United States)

    Nichols, Virginia A.

    It has been suggested that strategic incorporation of perennial vegetation into agricultural landscapes could provide ecosystem services while maintaining agricultural productivity. To evaluate potential use of prairie as a Midwestern cellulosic feedstock, we investigated theoretical cellulosic fuel yields, as well as soil-surface carbon dioxide emissions of prairie-based biofuel systems as compared to maize-based systems on fertile soils in Boone County, IA, USA. Investigated systems were: a maize-soybean rotation grown for grain only, continuous maize grown for grain and stover both with and without a winter rye cover crop, and a 31-species reconstructed prairie grown with and without spring nitrogen fertilization for fall-harvested biomass. From 2009-2013, the highest producing system was N-fertilized prairie, averaging 10.4 Mg ha -1 yr-1 above-ground biomass with average harvest removals of 7.8 Mg ha-1 yr-1. The unfertilized prairie produced 7.4 Mg ha-1 yr-1, averaging harvests of 5.3 Mg ha-1 yr-1. Lowest cellulosic biomass harvests were realized from continuous maize systems, averaging 3.5 Mg ha -1 yr-1 when grown with, and 3.7 Mg ha-1 yr-1 when grown without a winter rye cover crop, respectively. Un-fertilized prairie biomass and maize stover had equivalent dietary conversion ratios at 330 g ethanol kg-1 dry biomass, but N-fertilized prairie was lower at 315. Over four years prairie systems averaged 1287 L cellulosic ethanol ha-1 yr-1 more than maize systems, with fertilization increasing prairie ethanol production by 865 L ha-1 yr-1. Harvested biomass accounted for >90% of ethanol yield variation. A major hurdle in carbon cycling studies is the separation of the soil-surface CO2 flux into its respective components. From 2012-2013 we used a shading method to separate soil-surface CO2 resulting from oxidation of soil organic matter and CO2 derived from live-root activity in three systems: unfertilized prairie, N-fertilized prairie, and continuous maize

  9. Effects of insecticidal crystal proteins (Cry proteins) produced by genetically modified maize (Bt maize) on the nematode Caenorhabditis elegans

    International Nuclear Information System (INIS)

    Höss, Sebastian; Menzel, Ralph; Gessler, Frank; Nguyen, Hang T.; Jehle, Johannes A.; Traunspurger, Walter

    2013-01-01

    The genetically modified maize MON89034 × MON88017 expresses different crystal (Cry) proteins with pesticidal activity against the European corn borer (Cry1.105; Cry2Ab2) and the Western corn root worm (Cry3Bb1). Non-target organisms, such as soil nematodes, might be exposed to the Cry proteins that enter the soil in course of crop growing. Therefore, the risk of those proteins for nematodes was assessed by testing their toxic effects on Caenorhabditis elegans. All three insecticidal Cry proteins showed dose-dependent inhibitory effects on C. elegans reproduction (EC50: 0.12–0.38 μmol L −1 ), however, at concentrations that were far above the expected soil concentrations. Moreover, a reduced toxicity was observed when Cry proteins were added jointly. A C. elegans mutant strain deficient for receptors for the nematicidal Cry5B was also resistant against Cry1.105 and Cry2Ab2, suggesting that these Cry proteins bound to the same or similar receptors as nematicidal Cry proteins and thereby affect the reproduction of C. elegans. -- Highlights: •Insecticidal Cry proteins dose-dependently inhibited the reproduction of C. elegans. •Mixture toxicity was lower than expected from concentration-additive single effects. •Genes for MAPK-defense-pathway were up-regulated in presence of Cry protein mixture. •Knock-out strains deficient for Cry5B-receptors showed lower susceptibility to insecticidal Cry proteins. •Toxicity of insecticidal Cry-proteins on C. elegans occurred at concentrations far above expected field concentrations. -- Insecticidal Cry proteins expressed by genetically modified maize act on nematodes via a similar mode of action as nematicidal Cry proteins, however, at concentrations far above expected soil levels

  10. Core Promoter Plasticity Between Maize Tissues and Genotypes Contrasts with Predominance of Sharp Transcription Initiation Sites.

    Science.gov (United States)

    Mejía-Guerra, María Katherine; Li, Wei; Galeano, Narmer F; Vidal, Mabel; Gray, John; Doseff, Andrea I; Grotewold, Erich

    2015-12-01

    Core promoters are crucial for gene regulation, providing blueprints for the assembly of transcriptional machinery at transcription start sites (TSSs). Empirically, TSSs define the coordinates of core promoters and other regulatory sequences. Thus, experimental TSS identification provides an essential step in the characterization of promoters and their features. Here, we describe the application of CAGE (cap analysis of gene expression) to identify genome-wide TSSs used in root and shoot tissues of two maize (Zea mays) inbred lines (B73 and Mo17). Our studies indicate that most TSS clusters are sharp in maize, similar to mice, but distinct from Arabidopsis thaliana, Drosophila melanogaster, or zebra fish, in which a majority of genes have broad-shaped TSS clusters. We established that ∼38% of maize promoters are characterized by a broader TATA-motif consensus, and this motif is significantly enriched in genes with sharp TSSs. A noteworthy plasticity in TSS usage between tissues and inbreds was uncovered, with ∼1500 genes showing significantly different dominant TSSs, sometimes affecting protein sequence by providing alternate translation initiation codons. We experimentally characterized instances in which this differential TSS utilization results in protein isoforms with additional domains or targeted to distinct subcellular compartments. These results provide important insights into TSS selection and gene expression in an agronomically important crop. © 2015 American Society of Plant Biologists. All rights reserved.

  11. A highly conserved metalloprotease effector enhances virulence in the maize anthracnose fungus Colletotrichum graminicola.

    Science.gov (United States)

    Sanz-Martín, José M; Pacheco-Arjona, José Ramón; Bello-Rico, Víctor; Vargas, Walter A; Monod, Michel; Díaz-Mínguez, José M; Thon, Michael R; Sukno, Serenella A

    2016-09-01

    Colletotrichum graminicola causes maize anthracnose, an agronomically important disease with a worldwide distribution. We have identified a fungalysin metalloprotease (Cgfl) with a role in virulence. Transcriptional profiling experiments and live cell imaging show that Cgfl is specifically expressed during the biotrophic stage of infection. To determine whether Cgfl has a role in virulence, we obtained null mutants lacking Cgfl and performed pathogenicity and live microscopy assays. The appressorium morphology of the null mutants is normal, but they exhibit delayed development during the infection process on maize leaves and roots, showing that Cgfl has a role in virulence. In vitro chitinase activity assays of leaves infected with wild-type and null mutant strains show that, in the absence of Cgfl, maize leaves exhibit increased chitinase activity. Phylogenetic analyses show that Cgfl is highly conserved in fungi. Similarity searches, phylogenetic analysis and transcriptional profiling show that C. graminicola encodes two LysM domain-containing homologues of Ecp6, suggesting that this fungus employs both Cgfl-mediated and LysM protein-mediated strategies to control chitin signalling. © 2015 BSPP and John Wiley & Sons Ltd.

  12. Functional mechanisms of drought tolerance in subtropical maize (Zea mays L.) identified using genome-wide association mapping.

    Science.gov (United States)

    Thirunavukkarasu, Nepolean; Hossain, Firoz; Arora, Kanika; Sharma, Rinku; Shiriga, Kaliyugam; Mittal, Swati; Mohan, Sweta; Namratha, Pottekatt Mohanlal; Dogga, Sreelatha; Rani, Tikka Shobha; Katragadda, Sumalini; Rathore, Abhishek; Shah, Trushar; Mohapatra, Trilochan; Gupta, Hari Shankar

    2014-12-24

    Earlier studies were focused on the genetics of temperate and tropical maize under drought. We identified genetic loci and their association with functional mechanisms in 240 accessions of subtropical maize using a high-density marker set under water stress. Out of 61 significant SNPs (11 were false-discovery-rate-corrected associations), identified across agronomic traits, models, and locations by subjecting the accessions to water stress at flowering stage, 48% were associated with drought-tolerant genes. Maize gene models revealed that SNPs mapped for agronomic traits were in fact associated with number of functional traits as follows: stomatal closure, 28; flowering, 15; root development, 5; detoxification, 4; and reduced water potential, 2. Interactions of these SNPS through the functional traits could lead to drought tolerance. The SNPs associated with ABA-dependent signalling pathways played a major role in the plant's response to stress by regulating a series of functions including flowering, root development, auxin metabolism, guard cell functions, and scavenging reactive oxygen species (ROS). ABA signalling genes regulate flowering through epigenetic changes in stress-responsive genes. ROS generated by ABA signalling are reduced by the interplay between ethylene, ABA, and detoxification signalling transductions. Integration of ABA-signalling genes with auxin-inducible genes regulates root development which in turn, maintains the water balance by regulating electrochemical gradient in plant. Several genes are directly or indirectly involved in the functioning of agronomic traits related to water stress. Genes involved in these crucial biological functions interacted significantly in order to maintain the primary as well as exclusive functions related to coping with water stress. SNPs associated with drought-tolerant genes involved in strategic biological functions will be useful to understand the mechanisms of drought tolerance in subtropical maize.

  13. Effect of arbuscular mycorrhizal fungal inoculation in combination with different organic fertilizers on maize crop in eroded soils

    International Nuclear Information System (INIS)

    Sharif, M.; Saud, S.; Khan, F.

    2012-01-01

    A pot experiment was conducted to study the effect of inoculating maize (Zea mays L. Azam) with Arbuscular mycorrhizal (AM) fungi in 2 different series of North West Pakistan during the year 2007. Data showed significant increase in shoots and roots yield of maize with the inoculation of AM fungi alone and in combination with farm yard manure (FYM), poultry manure (PM) and humic acid (HA) over control and N-P-K treatments. Accumulation of N by maize shoots increased significantly by the addition of HA, PM and FYM plus N-P-K with or without inoculation of AM fungi over the treatments of N-P-K and control. Plants P accumulation increased significantly over control and N-P-K treatments with the inoculation of AM fungi alone and in combination with FYM, PM and HA in missa soil series. In missa gullied soil series, significantly increased plants P accumulation was noted by the treatments of AM inoculation with PM followed by HA. Accumulation of Mn by maize shoots increased significantly with AM inoculation with HA and PM over all other treatments, Fe increased with PM, HA and FYM. Plants Cu accumulation in missa series increased significantly over control and N-P-K treatments by AM alone and in combination with PM, FYM and HA and by AM fungi with PM, FYM and HA in missa gullied series. Maximum Mycorrhizal root infection rate of 51 % was recorded in the treatment of AM fungal inoculation with HA followed by the treatment inoculated with AM fungi with FYM. In missa gullied soil series, Maximum (59 %) and significantly increased roots infection rates over all treatments were observed in the treatment of AM fungal inoculation with HA followed by PM. Spores concentrations of AM fungi increased significantly with AM inoculation alone and with FYM, PM and HA. Maximum spores numbers of 50 in 20 g soil were recorded by the inoculation of AM fungi alone and with HA. (author)

  14. Carbaryl residues in maize and processed products

    International Nuclear Information System (INIS)

    Qureshi, M.J.; Sattar, A. Jr.; Naqvi, M.H.

    1981-01-01

    Carbaryl residues in two local maize varieties were determined using a colorimetric method. No significant differences were observed for residues of the two varieties which ranged between 12.0 to 13.75 mg/kg in the crude oil, and averaged 1.04 and 0.67 mg/kg in the flour and cake respectively. In whole maize plants, carbaryl residues declined to approximately 2 mg/kg 35 days after treatment. Cooking in aqueous, oil or aqueous-oil media led to 63-83% loss of carbaryl residues, after 30 minutes. (author)

  15. Forages and Pastures Symposium: development of and field experience with drought-tolerant maize.

    Science.gov (United States)

    Soderlund, S; Owens, F N; Fagan, C

    2014-07-01

    Drought-tolerant maize hybrids currently are being marketed by several seed suppliers. Such hybrids were developed by phenotypic and marker-assisted selection or through genetic modification and tested by exposing these hybrids to various degrees of water restriction. As drought intensifies, crop yields and survival progressively decline. Water need differs among plants due to differences in root structure, evaporative loss, capacity to store water or enter temporary dormancy, and plant genetics. Availability of water differs widely not only with rainfall and irrigation but also with numerous soil and agronomic factors (e.g., soil type, slope, seeding rates, tillage practices). Reduced weed competition, enhanced pollen shed and silk production, and deep, robust root growth help to reduce the negative impacts of drought. Selected drought-tolerant maize hybrids have consistently yielded more grain even when drought conditions are not apparent either due to reduced use of soil water reserves before water restriction or due to greater tolerance of intermittent water shortages. In DuPont Pioneer trials, whole plant NDF digestibility of maize increased with water restriction, perhaps due to an increased leaf to stem ratio. Efficiency of water use, measured as dry matter or potential milk yield from silage per unit of available water, responded quadratically to water restriction, first increasing slightly but then decreasing as water restriction increased. For grain production, water restriction has its greatest negative impact during or after silking through reducing the number of kernels and reducing kernel filling. For silage production, water restriction during the vegetative growth stage negatively impacts plant height and biomass yield. Earlier planting and shorter season maize hybrids help to avoid midsummer heat stress during pollination and can reduce the number of irrigation events needed. Although drought tolerance of maize hybrids has been improved due to

  16. Processing and statistical analysis of soil-root images

    Science.gov (United States)

    Razavi, Bahar S.; Hoang, Duyen; Kuzyakov, Yakov

    2016-04-01

    Importance of the hotspots such as rhizosphere, the small soil volume that surrounds and is influenced by plant roots, calls for spatially explicit methods to visualize distribution of microbial activities in this active site (Kuzyakov and Blagodatskaya, 2015). Zymography technique has previously been adapted to visualize the spatial dynamics of enzyme activities in rhizosphere (Spohn and Kuzyakov, 2014). Following further developing of soil zymography -to obtain a higher resolution of enzyme activities - we aimed to 1) quantify the images, 2) determine whether the pattern (e.g. distribution of hotspots in space) is clumped (aggregated) or regular (dispersed). To this end, we incubated soil-filled rhizoboxes with maize Zea mays L. and without maize (control box) for two weeks. In situ soil zymography was applied to visualize enzymatic activity of β-glucosidase and phosphatase at soil-root interface. Spatial resolution of fluorescent images was improved by direct application of a substrate saturated membrane to the soil-root system. Furthermore, we applied "spatial point pattern analysis" to determine whether the pattern (e.g. distribution of hotspots in space) is clumped (aggregated) or regular (dispersed). Our results demonstrated that distribution of hotspots at rhizosphere is clumped (aggregated) compare to control box without plant which showed regular (dispersed) pattern. These patterns were similar in all three replicates and for both enzymes. We conclude that improved zymography is promising in situ technique to identify, analyze, visualize and quantify spatial distribution of enzyme activities in the rhizosphere. Moreover, such different patterns should be considered in assessments and modeling of rhizosphere extension and the corresponding effects on soil properties and functions. Key words: rhizosphere, spatial point pattern, enzyme activity, zymography, maize.

  17. 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.

  18. Sequencing, assembly, and annotation of Maize B104 : A maize transformation resource

    Science.gov (United States)

    Maize transformation is complicated. Most lines are not readily cultured and transformed, making the germplasm available for genome engineering extremely limited. Developing a better understanding of the genomic regions responsible for differences in culturability and transformability would be a goo...

  19. 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).

  20. Soil C and N statuses determine the effect of maize inoculation by plant growth-promoting rhizobacteria on nitrifying and denitrifying communities.

    Science.gov (United States)

    Florio, Alessandro; Pommier, Thomas; Gervaix, Jonathan; Bérard, Annette; Le Roux, Xavier

    2017-08-21

    Maize inoculation by Azospirillum stimulates root growth, along with soil nitrogen (N) uptake and root carbon (C) exudation, thus increasing N use efficiency. However, inoculation effects on soil N-cycling microbial communities have been overlooked. We hypothesized that inoculation would (i) increase roots-nitrifiers competition for ammonium, and thus decrease nitrifier abundance; and (ii) increase roots-denitrifiers competition for nitrate and C supply to denitrifiers by root exudation, and thus limit or benefit denitrifiers depending on the resource (N or C) mostly limiting these microorganisms. We quantified (de)nitrifiers abundance and activity in the rhizosphere of inoculated and non-inoculated maize on 4 sites over 2 years, and ancillary soil variables. Inoculation effects on nitrification and nitrifiers (AOA, AOB) were not consistent between the three sampling dates. Inoculation influenced denitrifiers abundance (nirK, nirS) differently among sites. In sites with high C limitation for denitrifiers (i.e. limitation of denitrification by C > 66%), inoculation increased nirS-denitrifier abundance (up to 56%) and gross N 2 O production (up to 84%), likely due to increased root C exudation. Conversely, in sites with low C limitation (<47%), inoculation decreased nirS-denitrifier abundance (down to -23%) and gross N 2 O production (down to -18%) likely due to an increased roots-denitrifiers competition for nitrate.

  1. Biochar effect on maize yield and soil characteristics in five conservation farming sites in Zambia

    Science.gov (United States)

    Cornelissen, Gerard; Martinsen, Vegard; Shitumbanuma, Victor; Alling, Vanja; Breedveld, Gijs D.; Rutherford, David W.; Sparrevik, Magnus; Hale, Sarah E.; Obia, Alfred; Mulder, Jan

    2013-01-01

    Biochar addition to agricultural soils can improve soil fertility, with the added bonus of climate change mitigation through carbon sequestration. Conservation farming (CF) is precision farming, often combining minimum tillage, crop rotation and residue retention. In the present farmer-led field trials carried out in Zambia, the use of a low dosage biochar combined with CF minimum tillage was tested as a way to increase crop yields. Using CF minimum tillage allows the biochar to be applied to the area where most of the plant roots are present and mirrors the fertilizer application in CF practices. The CF practice used comprised manually hoe-dug planting 10-L sized basins, where 10%–12% of the land was tilled. Pilot trials were performed with maize cob biochar and wood biochar on five soils with variable physical/chemical characteristics. At a dosage as low as 4 tons/ha, both biochars had a strong positive effect on maize yields in the coarse white aeolian sand of Kaoma, West-Zambia, with yields of 444% ± 114% (p = 0.06) and 352% ± 139% (p = 0.1) of the fertilized reference plots for maize and wood biochar, respectively. Thus for sandy acidic soils, CF and biochar amendment can be a promising combination for increasing harvest yield. Moderate but non-significant effects on yields were observed for maize and wood biochar in a red sandy clay loam ultisol east of Lusaka, central Zambia (University of Zambia, UNZA, site) with growth of 142% ± 42% (p > 0.2) and 131% ± 62% (p > 0.2) of fertilized reference plots, respectively. For three other soils (acidic and neutral clay loams and silty clay with variable cation exchange capacity, CEC), no significant effects on maize yields were observed (p > 0.2). In laboratory trials, 5% of the two biochars were added to the soil samples in order to study the effect of the biochar on physical and chemical soil characteristics. The large increase in crop yield in Kaoma soil was tentatively explained by a combination of an

  2. Biochar Effect on Maize Yield and Soil Characteristics in Five Conservation Farming Sites in Zambia

    Directory of Open Access Journals (Sweden)

    Alfred Obia

    2013-04-01

    Full Text Available Biochar addition to agricultural soils can improve soil fertility, with the added bonus of climate change mitigation through carbon sequestration. Conservation farming (CF is precision farming, often combining minimum tillage, crop rotation and residue retention. In the present farmer-led field trials carried out in Zambia, the use of a low dosage biochar combined with CF minimum tillage was tested as a way to increase crop yields. Using CF minimum tillage allows the biochar to be applied to the area where most of the plant roots are present and mirrors the fertilizer application in CF practices. The CF practice used comprised manually hoe-dug planting 10-L sized basins, where 10%–12% of the land was tilled. Pilot trials were performed with maize cob biochar and wood biochar on five soils with variable physical/chemical characteristics. At a dosage as low as 4 tons/ha, both biochars had a strong positive effect on maize yields in the coarse white aeolian sand of Kaoma, West-Zambia, with yields of 444% ± 114% (p = 0.06 and 352% ± 139% (p = 0.1 of the fertilized reference plots for maize and wood biochar, respectively. Thus for sandy acidic soils, CF and biochar amendment can be a promising combination for increasing harvest yield. Moderate but non-significant effects on yields were observed for maize and wood biochar in a red sandy clay loam ultisol east of Lusaka, central Zambia (University of Zambia, UNZA, site with growth of 142% ± 42% (p > 0.2 and 131% ± 62% (p > 0.2 of fertilized reference plots, respectively. For three other soils (acidic and neutral clay loams and silty clay with variable cation exchange capacity, CEC, no significant effects on maize yields were observed (p > 0.2. In laboratory trials, 5% of the two biochars were added to the soil samples in order to study the effect of the biochar on physical and chemical soil characteristics. The large increase in crop yield in Kaoma soil was tentatively explained by a combination

  3. Biochar effect on maize yield and soil characteristics in five conservation farming sites in Zambia

    Science.gov (United States)

    Cornelissen, Gerard; Martinsen, Vegard; Shitumbanuma, Victor; Alling, Vanja; Breedveld, Gijs D.; Rutherford, David W.; Sparrevik, Magnus; Hale, Sarah E.; Obia, Alfred; Mulder, Jan

    2013-01-01

    Biochar addition to agricultural soils can improve soil fertility, with the added bonus of climate change mitigation through carbon sequestration. Conservation farming (CF) is precision farming, often combining minimum tillage, crop rotation and residue retention. In the present farmer-led field trials carried out in Zambia, the use of a low dosage biochar combined with CF minimum tillage was tested as a way to increase crop yields. Using CF minimum tillage allows the biochar to be applied to the area where most of the plant roots are present and mirrors the fertilizer application in CF practices. The CF practice used comprised manually hoe-dug planting 10-L sized basins, where 10%–12% of the land was tilled. Pilot trials were performed with maize cob biochar and wood biochar on five soils with variable physical/chemical characteristics. At a dosage as low as 4 tons/ha, both biochars had a strong positive effect on maize yields in the coarse white aeolian sand of Kaoma, West-Zambia, with yields of 444% ± 114% (p = 0.06) and 352% ± 139% (p = 0.1) of the fertilized reference plots for maize and wood biochar, respectively. Thus for sandy acidic soils, CF and biochar amendment can be a promising combination for increasing harvest yield. Moderate but non-significant effects on yields were observed for maize and wood biochar in a red sandy clay loam ultisol east of Lusaka, central Zambia (University of Zambia, UNZA, site) with growth of 142% ± 42% (p > 0.2) and 131% ± 62% (p > 0.2) of fertilized reference plots, respectively. For three other soils (acidic and neutral clay loams and silty clay with variable cation exchange capacity, CEC), no significant effects on maize yields were observed (p > 0.2). In laboratory trials, 5% of the two biochars were added to the soil samples in order to study the effect of the biochar on physical and chemical soil characteristics. The large increase in crop yield in Kaoma soil was tentatively explained by a combination of an

  4. Characterization of Potential Plant Growth Promoting Rhizobacteria Isolated from Maize (Zea mays L. in Central and Northern Benin (West Africa

    Directory of Open Access Journals (Sweden)

    Nadège A. Agbodjato

    2015-01-01

    Full Text Available Our study aims to characterize Plant Growth Promoting Rhizobacteria (PGPR isolated from maize roots in five agroecological zones of central and northern Benin. Sixty samples were collected at the rate of four samples per village and three villages per agroecological zone. Rhizobacteria strains were isolated from these samples and biochemically characterized. These strains were analyzed for some of their PGPR traits like ammonia production and hydrogen cyanide following conventional methods. Microbiological investigation of these samples has shown that maize rhizospheres in central and northern Benin contain a high diversity of microorganisms. A total of nine species of maize Plant Growth Promoting Rhizobacteria were identified. Those PGPR include five Bacillus species (B. polymyxa, B. pantothenticus, B. anthracis, B. thuringiensis, and B. circulans, three Pseudomonas species (P. cichorii, P. putida, and P. syringae, and Serratia marcescens. The microbial diversity does not depend on the soil types. The microbial density, generally high, varies according to both soil types and agroecological zones. All Serratia strains (100% have produced ammonia, whereas 80% of Bacillus and 77.77% of Pseudomonas produced this metabolite. The hydrogen cyanide was produced by all isolates (100% independent of their genus. These results suggest the possibility to use these rhizobacteria as biological fertilizers to increase maize production.

  5. Phylloplane bacteria of Jatropha curcas: diversity, metabolic characteristics, and growth-promoting attributes towards vigor of maize seedling.

    Science.gov (United States)

    Dubey, Garima; Kollah, Bharati; Ahirwar, Usha; Mandal, Asit; Thakur, Jyoti Kumar; Patra, Ashok Kumar; Mohanty, Santosh Ranjan

    2017-10-01

    The complex role of phylloplane microorganisms is less understood than that of rhizospheric microorganisms in lieu of their pivotal role in plant's sustainability. This experiment aims to study the diversity of the culturable phylloplane bacteria of Jatropha curcas and evaluate their growth-promoting activities towards maize seedling vigor. Heterotrophic bacteria were isolated from the phylloplane of J. curcas and their 16S rRNA genes were sequenced. Sequences of the 16S rRNA gene were very similar to those of species belonging to the classes Bacillales (50%), Gammaproteobacteria (21.8%), Betaproteobacteria (15.6%), and Alphaproteobacteria (12.5%). The phylloplane bacteria preferred to utilize alcohol rather than monosaccharides and polysaccharides as a carbon source. Isolates exhibited ACC (1-aminocyclopropane-1-carboxylic acid) deaminase, phosphatase, potassium solubilization, and indole acetic acid (IAA) production activities. The phosphate-solubilizing capacity (mg of PO 4 solubilized by 10 8 cells) varied from 0.04 to 0.21. The IAA production potential (μg IAA produced by 10 8 cells in 48 h) of the isolates varied from 0.41 to 9.29. Inoculation of the isolates to maize seed significantly increased shoot and root lengths of maize seedlings. A linear regression model of the plant-growth-promoting activities significantly correlated (p < 0.01) with the growth parameters. Similarly, a correspondence analysis categorized ACC deaminase and IAA production as the major factors contributing 41% and 13.8% variation, respectively, to the growth of maize seedlings.

  6. Responses of Seed Germination, Seedling Growth, and Seed Yield Traits to Seed Pretreatment in Maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Yu Tian

    2014-01-01

    Full Text Available A series of seed priming experiments were conducted to test the effects of different pretreatment methods to seed germination, seedling growth, and seed yield traits in maize (Zea mays L.. Results indicated that the seeds primed by gibberellins (GA, NaCl, and polyethylene glycol (PEG reagents showed a higher imbibitions rate compared to those primed with water. The final germination percentage and germination rate varied with different reagents significantly (P<0.05. The recommended prime reagents were GA at 10 mg/L, NaCl at 50 mM, and PEG at 15% on account of germination experiment. 15% PEG priming reagent increased shoot and root biomass of maize seedling. The shoot biomass of seedlings after presoaking the seeds with NaCl reagent was significantly higher than the seedlings without priming treatment. No significant differences of plant height, leaf number, and hundred-grain weight were observed between control group and priming treatments. Presoaking with water, NaCl (50 mM, or PEG (15% significantly increased the hundred-grain weight of maize. Therefore, seed pretreatment is proved to be an effective technique to improve the germination performance, seedling growth, and seed yield of maize. However, when compared with the two methods, if immediate sowing is possible, presoaking is recommended to harvest better benefits compared to priming method.

  7. Responses of seed germination, seedling growth, and seed yield traits to seed pretreatment in maize (Zea mays L.).

    Science.gov (United States)

    Tian, Yu; Guan, Bo; Zhou, Daowei; Yu, Junbao; Li, Guangdi; Lou, Yujie

    2014-01-01

    A series of seed priming experiments were conducted to test the effects of different pretreatment methods to seed germination, seedling growth, and seed yield traits in maize (Zea mays L.). Results indicated that the seeds primed by gibberellins (GA), NaCl, and polyethylene glycol (PEG) reagents showed a higher imbibitions rate compared to those primed with water. The final germination percentage and germination rate varied with different reagents significantly (P germination experiment. 15% PEG priming reagent increased shoot and root biomass of maize seedling. The shoot biomass of seedlings after presoaking the seeds with NaCl reagent was significantly higher than the seedlings without priming treatment. No significant differences of plant height, leaf number, and hundred-grain weight were observed between control group and priming treatments. Presoaking with water, NaCl (50 mM), or PEG (15%) significantly increased the hundred-grain weight of maize. Therefore, seed pretreatment is proved to be an effective technique to improve the germination performance, seedling growth, and seed yield of maize. However, when compared with the two methods, if immediate sowing is possible, presoaking is recommended to harvest better benefits compared to priming method.

  8. Developing Inset Resistant Maize Varieties for Food Security in Kenya

    International Nuclear Information System (INIS)

    Mugo, S.

    2002-01-01

    The Insect Resistant Maize for Africa (IRMA) project aims at increasing maize production and food security through development and deployment of stem borer resistant maize germplasm developed using conventional and through biotechnology methods such as Bt maize. Bt maize offers farmers an effective and practical option for controlling stem borers. It was recognized that the development and routine use of Bt maize will require addressing relevant bio-safety, environmental, and community concerns and research and information gathering activities are in place to address these concerns and research and information gathering activities are in place to address these concerns. Suitable Bt gene have been acquired or synthesized and back-crossed into elite maize germplasm at CIMMYT-Mexico, and the effective Cry-proteins against the major maize stem borers in Kenya were identified to better target pests. Stem borer resistant maize germplasm is being developed through conventional breeding, using locally adapted and exotic germplasm. for safe and effective deployment of Bt maize,studies on its impacts on target and non-target arthropods as well as studies on the effects of Bt maize on key non-target arthropods as well as studies on gene flow are underway. Insect resistance management strategies are being developed through quantifying the effectiveness, ???. Socioeconomic impact studies are revealing factors in the society that may influence the adoption of Bt maize in Kenya. Also, baseline data, essential for the monitoring and evaluation of the Bt maize technology in Kenya, has been established. Technology transfer and capacity building, creating awareness and communications have received attention in the project. This paper describes the major research activities as they relate to development of the stem bore resistant maize germplasm

  9. Bacterial endophytes from wild maize suppress Fusarium graminearum in modern maize and inhibit mycotoxin accumulation

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    Walaa Kamel Mousa

    2015-10-01

    Full Text Available Wild maize (teosinte has been reported to be less susceptible to pests than their modern maize (corn relatives. Endophytes, defined as microbes that inhabit plants without causing disease, are known for their ability to antagonize plant pests and pathogens. We hypothesized that the wild relatives of modern maize may host endophytes that combat pathogens. Fusarium graminearum is the fungus that causes Gibberella Ear Rot (GER in modern maize and produces the mycotoxin, deoxynivalenol (DON. In this study, 215 bacterial endophytes, previously isolated from diverse maize genotypes including wild teosintes, traditional landraces and modern varieties, were tested for their ability to antagonize F. graminearum in vitro. Candidate endophytes were then tested for their ability to suppress GER in modern maize in independent greenhouse trials. The results revealed that three candidate endophytes derived from wild teosintes were most potent in suppressing F. graminearum in vitro and GER in a modern maize hybrid. These wild teosinte endophytes could suppress a broad spectrum of fungal pathogens of modern crops in vitro. The teosinte endophytes also suppressed DON mycotoxin during storage to below acceptable safety threshold levels. A fourth, less robust anti-fungal strain was isolated from a modern maize hybrid. Three of the anti-fungal endophytes were predicted to be Paenibacillus polymyxa, along with one strain of Citrobacter. Microscopy studies suggested a fungicidal mode of action by all four strains. Molecular and biochemical studies showed that the P. polymyxa strains produced the previously characterized anti-Fusarium compound, fusaricidin. Our results suggest that the wild relatives of modern crops may serve as a valuable reservoir for endophytes in the ongoing fight against serious threats to modern agriculture. We discuss the possible impact of crop evolution and domestication on endophytes in the context of plant defense.

  10. Occurrence of toxigenic fungi in maize and maize-gluten meal from Pakistan

    Directory of Open Access Journals (Sweden)

    Muhammad Kashif SALEEMI

    2012-05-01

    Full Text Available The present study was designed to isolate and identify toxigenic mycoflora of maize and maize-gluten meal. A total of 82 samples of maize and 8 samples of maize-gluten meal were collected from Faisalabad district of Pakistan over a period of two years. These samples were inoculated on different culture media. Fungal contamination of maize and maize-gluten was 56% and 75% of samples, respectively. Isolation frequencies of different genera isolated from maize were Aspergillus 33%; Penicillium 28%; Fusarium 10%; and Alternaria 1%. Isolation frequency among species was maximum for P. verrucosum, followed by A. niger aggregates, A. ochraceous, A. flavus, P. chrysogenum, A. parasiticus, A. carbonarius, Fusarium spp. and Alternaria spp. Relative density of Aspergillus isolates was maximum for A. niger aggregates and A. ochraceous (30% each followed by A. flavus (26%, A. parasiticus (11% and A. carbonarius (3%. Percentage of toxigenic fungi among Aspergillus isolates was 52%. Aflatoxigenic isolates of A. flavus and A. parasiticus were 43 and 67% and ochratoxigenic isolates of A. carbonarius, A. ochraceous and A. niger aggregates were 100, 63 and 38%, respectively. Aspergillus parasiticus produced higher concentrations of AFB1 (maximum 1374.23 ng g-1 than A. flavus (maximum 635.50 ng g-1. Ochratoxin A production potential of A. ochraceous ranged from 1.81 to 9523.1 ng g-1, while in A. niger aggregates it was 1.30 to 1758.6 ng g-1. Isolation frequencies of fungal genera from maize-gluten meal were Aspergillus (63% and Penicillium (50%. A. flavus was the most frequently isolated species. Percentage of toxigenic fungi among Aspergillus isolates was 40%. Aflatoxigenic isolates of A. flavus were 33% and ochratoxigenic isolates of A. ochraceous were 100%.

  11. Effect of diazotrophic bacteria as phosphate solubilizing and indolic compound producers on maize plants

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    Mónica Del Pilar López Ortega

    2013-07-01

    Full Text Available Phosphorus is limiting for growth of maize plants, and because of that use of fertilizers like Rock Phosphate has been proposed. However, direct use of Rock Phosphate is not recommended because of its low availability, so it is necessary to improve it. In this study, a group of diazotrophic bacteria were evaluated as phosphate-solubilizing bacteria, for their production of indolic compounds and for their effects on growth of maize plants. Strains of the genera Azosporillum, Azotobacter, Rhizobium and Klebsiella, were quantitatively evaluated for solubilization of Ca3(PO42 and rock phosphate as a single source of phosphorous in SRS culture media. Additionally, the phosphatase enzyme activity was quantified at pH 5.0, 7.0 and 8.0 using p-nitrophenyl phosphate, and production of indolic compound was determined by colorimetric quantification. The effect of inoculation of bacteria on maize was determined in a completely randomized greenhouse experiment where root and shoot dry weights and phosphorus content were assessed. Results showed that strain C50 produced 107.2 mg .L-1 of available-P after 12 days of fermentation, and AC10 strain had the highest phosphatase activity at pH 8 with 12.7 mg of p-nitrophenol mL .h-1. All strains synthetized indolic compounds, and strain AV5 strain produced the most at 63.03 µg .mL-1. These diazotrophic bacteria increased plant biomass up to 39 % and accumulation of phosphorus by 10%. Hence, use of diazotrphic phosphate-solubilizing bacteria may represent an alternative technology for fertilization systems in maize plants.

  12. Remediation of Arsenic contaminated soil using malposed intercropping of Pteris vittata L. and maize.

    Science.gov (United States)

    Ma, Jie; Lei, En; Lei, Mei; Liu, Yanhong; Chen, Tongbin

    2018-03-01

    Intercropping of arsenic (As) hyperaccumulator and cash crops during remediation of contaminated soil has been applied in farmland remediation project. However, little is known about the fate of As fractions in the soil profile and As uptake within the intercropping plants under field condition. In this study, As removal, uptake, and translocation were investigated within an intercropping system of Pteris vittata L. (P. vittata) and maize (Zea mays). Results indicated that the concentration of As associated with amorphous Fe (hydr)oxides in the 10-20 cm soil layer was significantly lower under malposed intercropping of P. vittata and maize, and As accumulation in P. vittata and biomass of P. vittata were simultaneously higher under malposed intercropping than under coordinate intercropping, leading to a 2.4 times higher rate of As removal. Although maize roots absorbed over 13.4 mg kg -1 As and maize leaves and flowers accumulated over 21.5 mg kg -1 As (translocation factor higher than 1), grains produced in all intercropping modes accumulated lower levels of As, satisfying the standard for human consumption. Our results suggested that malposed intercropping of a hyperaccumulator and a low-accumulation cash crop was an ideal planting pattern for As remediation in soil. Furthermore, timely harvest of P. vittata, agronomic strategies during remediation, and appropriate management of the above ground parts of P. vittata and high-As tissues of cash crops may further improve remediation efficiency. Copyright © 2017. Published by Elsevier Ltd.

  13. Screening of promising maize genotypes against maize weevil (Sitophilus zeamais Motschulky in storage condition

    Directory of Open Access Journals (Sweden)

    Ram B Paneru

    2017-12-01

    Full Text Available The maize weevil (Sitophilus zeamais Motschulsky is a serious pest of economic importance in stored grains. It causes major damage to stored maize grain thereby reducing its weight, quality and germination. An experiment was conducted in randomized complete block design (RCBD with 3 replications to screen 32 maize genotypes against maize weevil in no-choice and free-choice conditions at Entomology Division, Khumaltar, Lalitpur (Room temperature: Maximum 24-32°C and Minimum 18-27°C. The findings showed that the maize genotypes had different response to maize weevil damage ranging from susceptible to tolerance. The genotypes Manakamana-3, Lumle White POP Corn and Ganesh-2 showed their tolerance to S. zeamais as evidenced by lower number of weevil emerged/attracted, lower amount of grain debris release and lower proportion of bored grains, while the genotype ZM-627 was the most susceptible to weevil damage in both tests. The other remaining genotypes were intermediate types. This information is useful to improve grain protection in storage and varietal improvement/release program.

  14. Striga parasitizes transgenic hairy roots of Zea mays and provides a tool for studying plant-plant interactions

    Directory of Open Access Journals (Sweden)

    Runo Steven

    2012-06-01

    Full Text Available Abstract Background Striga species are noxious root hemi-parasitic weeds that debilitate cereal production in sub-Saharan Africa (SSA. Control options for Striga are limited and developing Striga resistant crop germplasm is regarded as the best and most sustainable control measure. Efforts to improve germplasm for Striga resistance by a non-Genetic Modification (GM approach, for example by exploiting natural resistance, or by a GM approach are constrained by limited information on the biological processes underpinning host-parasite associations. Additionaly, a GM approach is stymied by lack of availability of candidate resistance genes for introduction into hosts and robust transformation methods to validate gene functions. Indeed, a majority of Striga hosts, the world’s most cultivated cereals, are recalcitrant to genetic transformation. In maize, the existing protocols for transformation and regeneration are tedious, lengthy, and highly genotype-specific with low efficiency of transformation. Results We used Agrobacterium rhizogenes strain K599 carrying a reporter gene construct, Green Fluorescent Protein (GFP, to generate transgenic composite maize plants that were challenged with the parasitic plant Striga hermonthica. Eighty five percent of maize plants produced transgenic hairy roots expressing GFP. Consistent with most hairy roots produced in other species, transformed maize roots exhibited a hairy root phenotype, the hallmark of A. rhizogenes mediated transformation. Transgenic hairy roots resulting from A. rhizogenes transformation were readily infected by S. hermonthica. There were no significant differences in the number and size of S. hermonthica individuals recovered from either transgenic or wild type roots. Conclusions This rapid, high throughput, transformation technique will advance our understanding of gene function in parasitic plant-host interactions.

  15. Importance of PGPR application and its effect on microbial activity in maize rhizosphere

    Directory of Open Access Journals (Sweden)

    Mrkovački Nastasija

    2012-01-01

    Full Text Available Microorganisms are involved in the formation of soil fertility, both potential and effective. They facilitate the processes of humification and dehumification and play a key role in the cycling of nutrients - macro and microelements. Rhizosphere is the soil in direct contact with plant roots and influenced by plant exudates. Root exudates of maize significantly affect the composition and abundance of microorganisms in the rhizosphere. Bio-fertilizers are microbial fertilizers composed of highly effective strains of bacteria, algae and fungi isolated from soil. Their application activates microbial processes that secure a better and steadier supply of plants with nitrogen, phosphorus, potassium and some micronutrients. The application of PGPR-containing biofertilizers reduces the need for expensive nitrogen fertilizers, facilitates phosphorus uptake by plants and affects the direction and dynamics of microbial processes.

  16. Historical genomics of North American maize

    NARCIS (Netherlands)

    Heerwaarden, van J.; Hufford, M.B.; Ross-Ibarra, J.

    2012-01-01

    Since the advent of modern plant breeding in the 1930s, North American maize has undergone a dramatic adaptation to high-input agriculture. Despite the importance of genetic contributions to historical yield increases, little is known about the underlying genomic changes. Here we use high-density

  17. Hormonal responses during early embryogenesis in maize.

    Science.gov (United States)

    Chen, Junyi; Lausser, Andreas; Dresselhaus, Thomas

    2014-04-01

    Plant hormones have been shown to regulate key processes during embryogenesis in the model plant Arabidopsis thaliana, but the mechanisms that determine the peculiar embryo pattern formation of monocots are largely unknown. Using the auxin and cytokinin response markers DR5 and TCSv2 (two-component system, cytokinin-responsive promoter version #2), as well as the auxin efflux carrier protein PIN1a (PINFORMED1a), we have studied the hormonal response during early embryogenesis (zygote towards transition stage) in the model and crop plant maize. Compared with the hormonal response in Arabidopsis, we found that detectable hormone activities inside the developing maize embryo appeared much later. Our observations indicate further an important role of auxin, PIN1a and cytokinin in endosperm formation shortly after fertilization. Apparent auxin signals within adaxial endosperm cells and cytokinin responses in the basal endosperm transfer layer as well as chalazal endosperm are characteristic for early seed development in maize. Moreover, auxin signalling in endosperm cells is likely to be involved in exogenous embryo patterning as auxin responses in the endosperm located around the embryo proper correlate with adaxial embryo differentiation and outgrowth. Overall, the comparison between Arabidopsis and maize hormone response and flux suggests intriguing mechanisms in monocots that are used to direct their embryo patterning, which is significantly different from that of eudicots.

  18. INSECT AND MYCOFLORA INTERACTIONS IN MAIZE FLOUR ...

    African Journals Online (AJOL)

    Fusarium moniliforme had the highest occurrence of 36.7%, 28.1% and 33.3% while Aspergillus flavus/parasiticus had a frequency of 3.2%, 3.1% and 3% on primary isolation media of czapek dox agar (CDA), potato dextrose agar (PDA) and sabouraud dextrose agar (SDA) respectively, in maize flour without T. castaneum.

  19. The transcriptome landscape of early maize meiosis

    Science.gov (United States)

    Meiosis, particularly meiotic recombination, is a major factor affecting yield and breeding of plants. To gain insight into the transcriptome landscape during early initiation steps of meiotic recombination, we profiled early prophase I meiocytes from maize using RNA-seq. Our analyses of genes prefe...

  20. RESOURCE UTILISATION IN SOYBEAN/MAIZE INTERCROPS ...

    African Journals Online (AJOL)

    Soybean and maize may be planted as intercrops in alternating single rows in forage production systems to take advantage of available solar radiation and greater dry matter yields. Key Words: Nitrogen, row arrangement, photosynthetic active radiation, productivity. Résumé Des études des champs étaient conduites en ...

  1. Estimation of leaf area in tropical maize

    NARCIS (Netherlands)

    Elings, A.

    2000-01-01

    Leaf area development of six tropical maize cultivars grown in 1995 and 1996 in several tropical environments in Mexico (both favourable and moisture-and N-limited) was observed and analysed. First, the validity of a bell-shaped curve describing the area of individual leaves as a function of leaf

  2. Interactive Effects of Elevated [CO2] and Drought on the Maize Phytochemical Defense Response against Mycotoxigenic Fusarium verticillioides.

    Directory of Open Access Journals (Sweden)

    Martha M Vaughan

    Full Text Available Changes in climate due to rising atmospheric carbon dioxide concentration ([CO2] are predicted to intensify episodes of drought, but our understanding of how these combined conditions will influence crop-pathogen interactions is limited. We recently demonstrated that elevated [CO2] alone enhances maize susceptibility to the mycotoxigenic pathogen, Fusarium verticillioides (Fv but fumonisin levels remain unaffected. In this study we show that maize simultaneously exposed to elevated [CO2] and drought are even more susceptible to Fv proliferation and also prone to higher levels of fumonisin contamination. Despite the increase in fumonisin levels, the amount of fumonisin produced in relation to pathogen biomass remained lower than corresponding plants grown at ambient [CO2]. Therefore, the increase in fumonisin contamination was likely due to even greater pathogen biomass rather than an increase in host-derived stimulants. Drought did not negate the compromising effects of elevated [CO2] on the accumulation of maize phytohormones and metabolites. However, since elevated [CO2] does not influence the drought-induced accumulation of abscisic acid (ABA or root terpenoid phytoalexins, the effects elevated [CO2] are negated belowground, but the stifled defense response aboveground may be a consequence of resource redirection to the roots.

  3. Interactive Effects of Elevated [CO2] and Drought on the Maize Phytochemical Defense Response against Mycotoxigenic Fusarium verticillioides

    Science.gov (United States)

    Vaughan, Martha M.; Huffaker, Alisa; Schmelz, Eric A.; Dafoe, Nicole J.; Christensen, Shawn A.; McAuslane, Heather J.; Alborn, Hans T.; Allen, Leon Hartwell; Teal, Peter E. A.

    2016-01-01

    Changes in climate due to rising atmospheric carbon dioxide concentration ([CO2]) are predicted to intensify episodes of drought, but our understanding of how these combined conditions will influence crop-pathogen interactions is limited. We recently demonstrated that elevated [CO2] alone enhances maize susceptibility to the mycotoxigenic pathogen, Fusarium verticillioides (Fv) but fumonisin levels remain unaffected. In this study we show that maize simultaneously exposed to elevated [CO2] and drought are even more susceptible to Fv proliferation and also prone to higher levels of fumonisin contamination. Despite the increase in fumonisin levels, the amount of fumonisin produced in relation to pathogen biomass remained lower than corresponding plants grown at ambient [CO2]. Therefore, the increase in fumonisin contamination was likely due to even greater pathogen biomass rather than an increase in host-derived stimulants. Drought did not negate the compromising effects of elevated [CO2] on the accumulation of maize phytohormones and metabolites. However, since elevated [CO2] does not influence the drought-induced accumulation of abscisic acid (ABA) or root terpenoid phytoalexins, the effects elevated [CO2] are negated belowground, but the stifled defense response aboveground may be a consequence of resource redirection to the roots. PMID:27410032

  4. The 50th Annual Maize Genetics Conference

    Energy Technology Data Exchange (ETDEWEB)

    Cone, Karen

    2014-03-26

    The 50th Annual Maize Genetics Conference was held February 27 - March 2, 2008 at the Marriott Wardman Park Hotel in Washington, D.C. As the golden anniversary of the Conference and coinciding with the release of a draft of the maize genome sequence, this was a special meeting. To publicize this unique occasion, meeting organizers hosted a press conference, which was attended by members of the press representing science and non-science publications, and an evening reception at the Smithsonian National Museum of Natural History, where the draft sequence was announced and awards were presented to Dr. Mary Clutter and Senator Kit Bond to thank them for their outstanding contributions to maize genetics and genomics research. As usual, the Conference provided an invigorating forum for exchange of recent research results in many areas of maize genetics, e.g., cytogenetics, development, molecular genetics, transposable element biology, biochemical genetics, and genomics. Results were shared via both oral and poster presentations. Invited talks were given by four distinguished geneticists: Vicki Chandler, University of Arizona; John Doebley, University of Wisconsin; Susan Wessler, University of Georgia; and Richard Wilson, Washington University. There were 46 short talks and 241 poster presentations. The Conference was attended by over 500 participants. This included a large number of first-time participants in the meeting and an increasingly visible presence by individuals from underrepresented groups. Although we do not have concrete counts, there seem to be more African American, African and Hispanic/Latino attendees coming to the meeting than in years past. In addition, this meeting attracted many participants from outside the U.S. Student participation continues to be hallmark of the spirit of free exchange and cooperation characteristic of the maize genetics community. With the generous support provided by DOE, USDA NSF, and corporate/private donors, organizers were

  5. Effect of organic fertilizers on maize production in Eastern Georgia

    Science.gov (United States)

    Jolokhava, Tamar; Kenchiashvili, Naira; Tarkhnishvili, Maia; Ghambashidze, Giorgi

    2016-04-01

    Maize remains to be the most important cereal crop in Georgia. Total area of arable land under cereal crops production equals to 184 thousands hectares (FAO statistical yearbook, 2014), from which maize takes the biggest share. Leading position of maize among other cereal crops is caused by its dual purpose as food and feed product. In Spite of a relatively high production of maize to other cereals there is still a high demand on it, especially as feed for animal husbandry. The same tendency is seen in organic production, where producers of livestock and poultry products require organically grown maize, the average yield of which is much less than those produced conventionally. Therefore, it is important to increase productivity of maize in organic farms. Current study aimed to improve maize yield using locally produced organic fertilizers and to compare them to the effect of mineral fertilizers. The study was carried out in Eastern Georgia under dry subtropical climate conditions on local hybrid of maize. This is the first attempt to use hybrid maize (developed with organic plant breeding method) in organic field trials in Georgia. The results shown, that grain yield from two different types of organic fertilizers reached 70% of the yields achieved with industrial mineral fertilizers. As on farm level differences between organic and conventional maize production are much severe, the results from the field trials seems to be promising for future improvement of organic cereal crop production.

  6. Differential Ability of Maize and Soybean to Acquire and Utilize Phosphorus from Sparingly Soluble Forms in Low- and Medium-P Soils Using {sup 32}P

    Energy Technology Data Exchange (ETDEWEB)

    Adu-Gyamfi, J. J.; Aigner, M.; Linic, S. [Soil and Water Management and Crop Nutrition Laboratory, Seibersdorf (Austria); Gludovacz, D. [Nuclear Material Laboratory, Safeguard Analytical Services, International Atomic Energy Agency, Seibersdorf (Austria)

    2013-11-15

    A glasshouse pot experiment was conducted to evaluate the differential ability of maize (Zea mays) and soybean (Glycine max) to utilize soil phosphorus (P) for plant growth from total-P, available-P and inorganic (Ca-P, Al-P and Fe-P) soil P pools using a carrier-free {sup 32}P solution. A maize variety (DK 315) and a soybean variety (TGX 1910-4F) were grown in pots containing 1 kg of a low available P soil (Hungarian) or a medium available P (Waldviertel) soil labelled with {sup 32}P for 42 days or without {sup 32}P (unlabelled) for 42 and 60 days. The shoot and root biomass of maize and soybean were significantly greater when grown on the Waldviertel than on the Hungarian soils. The shoot P concentrations were higher for soybean (1.7-2.2 g kg{sup -1}) than for maize (1.1-1.4 g kg{sup -1}). The total radioactivity (dpm x 10{sup 6}) was higher in plants grown in Waldviertel than in Hungarian soil and the values reflected plant P uptake and shoot biomass of soybean and maize. The L-values ({mu}g P g soil{sup -1}) of maize and soybean were higher in Waldviertel (72-78) than in Hungarian (9.6-20) soil. No significant differences in L-values were observed for maize and soybean grown on the Waldviertel soil, but for the Hungarian soil, the L-values were higher for maize (20.0) than for soybean (9.6) suggesting that in this low-P soil, maize was more efficient than soybean in taking up soil P. The available P (Bray II) and the Ca-P were the fractions most depleted by plants followed by the Fe-P fractions in the two soils, but differences between the crops were not significant. When soil P is limited, maize and soybean are able to access P mainly from the available P (Bray II), Fe- and Ca-P sparingly soluble fractions and not Al-P from the soil. (author)

  7. Studies on the traditional methods of production of maize tuwo (a ...

    African Journals Online (AJOL)

    African Journal of Food, Agriculture, Nutrition and Development ... on the quality characteristics of maize tuwo (a Nigerian nonfermented maize dumpling) ... The sequential mixing of flour and water during maize tuwo preparation should also ...

  8. The platelet-activating factor acetylhydrolase gene derived from Trichoderma harzianum induces maize resistance to Curvularia lunata through the jasmonic acid signaling pathway.

    Science.gov (United States)

    Yu, Chuanjin; Fan, Lili; Gao, Jinxin; Wang, Meng; Wu, Qiong; Tang, Jun; Li, Yaqian; Chen, Jie

    2015-01-01

    Platelet-activating factor acetylhydrolase (PAF-AH) derived from Trichoderma harzianum was upregulated by the interaction of T. harzianum with maize roots or the foliar pathogen Curvularia lunata. PAF-AH was associated with chitinase and cellulase expressions, but especially with chitinase, because its activity in the KO40 transformant (PAF-AH disruption transformant) was lower, compared with the wild-type strain T28. The result demonstrated that the colonization of maize roots by T. harzianum induced systemic protection of leaves inoculated with C. lunata. Such protection was associated with the expression of inducible jasmonic acid pathway-related genes. Moreover, the data from liquid chromatography-mass spectrometry confirmed that the concentration of jasmonic acid in maize leaves was associated with the expression level of defense-related genes, suggesting that PAF-AH induced resistance to the foliar pathogen. Our findings showed that PAF-AH had an important function in inducing systemic resistance to maize leaf spot pathogen.

  9. Cadmium toxicity in Maize (Zea mays L.): consequences on antioxidative systems, reactive oxygen species and cadmium accumulation.

    Science.gov (United States)

    Anjum, Shakeel Ahmad; Tanveer, Mohsin; Hussain, Saddam; Bao, Mingchen; Wang, Longchang; Khan, Imran; Ullah, Ehsan; Tung, Shahbaz Atta; Samad, Rana Abdul; Shahzad, Babar

    2015-11-01

    Increased cadmium (Cd) accumulation in soils has led to tremendous environmental problems, with pronounced effects on agricultural productivity. Present study investigated the effects of Cd stress imposed at various concentrations (0, 75, 150, 225, 300, 375 μM) on antioxidant activities, reactive oxygen species (ROS), Cd accumulation, and productivity of two maize (Zea mays L.) cultivars viz., Run Nong 35 and Wan Dan 13. Considerable variations in Cd accumulation and in behavior of antioxidants and ROS were observed under Cd stress in both maize cultivars, and such variations governed by Cd were concentration dependent. Exposure of plant to Cd stress considerably increased Cd concentration in all plant parts particularly in roots. Wan Dan 13 accumulated relatively higher Cd in root, stem, and leaves than Run Nong 35; however, in seeds, Run Nong 35 recorded higher Cd accumulation. All the Cd toxicity levels starting from 75 μM enhanced H2O2 and MDA concentrations and triggered electrolyte leakage in leaves of both cultivars, and such an increment was more in Run Nong 35. The ROS were scavenged by the enhanced activities of superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, and glutathione peroxidase in response to Cd stress, and these antioxidant activities were higher in Wan Dan 13 compared with Run Nong 35 at all Cd toxicity levels. The grain yield of maize was considerably reduced particularly for Run Nong 35 under different Cd toxicity levels as compared with control. The Wan Dan 13 was better able to alleviate Cd-induced oxidative damage which was attributed to more Cd accumulation in roots and higher antioxidant activities in this cultivar, suggesting that manipulation of these antioxidants and enhancing Cd accumulation in roots may lead to improvement in Cd stress tolerance.

  10. The relative contribution of natural zinc complexing agents and ZnSO4 to growth and zinc nutrition of maize

    International Nuclear Information System (INIS)

    Kumar, M.; Prasad, B.

    1989-01-01

    Relative evaluation of different natural zinc-complexes indicated that application of Zn-FA 2 (PM), Zn-FA 3 (Comp), Zn-FA 1 (BGS), Zn-FA 5 (PR), Zn-FA 4 (SS) and ZnSO 4 significantly enhanced the drymatter yield and zinc uptake by maize. The natural zinc-complexes in particular increased, to a greater extent, the uptake of both native and applied sources than that observed with ZnSO 4 as zinc carrier. Significant positive relationship between self-diffusion coefficient of Zn and drymatter yield and uptake of zinc by maize suggested that diffusion is responsible for the supply of zinc from ambient soil matrix to plant roots. (author). 12 refs., 5 tabs

  11. 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