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Sample records for cucurbit leaf crumple

  1. Confirmation of bean leaf beetle, Cerotoma trifurcata, feeding on cucurbits

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    R.L. Koch

    2004-02-01

    Full Text Available The objective of these studies was to assess the degree to which bean leaf beetle, Cerotoma trifurcata (Forster, will feed on cucurbits. In 2003, we documented an infestation of C. trifurcata in a commercial pumpkin field near Rosemount, MN, USA. To evaluate C. trifurcata feeding on cucurbits, we conducted laboratory no-choice and choice test feeding studies. In the laboratory, C. trifurcata fed most heavily on cotyledon-stage cucumber plants, followed by pumpkin and squash. With soybean plants present, C. trifurcata still fed on cucumber plants. However, C. trifurcata appeared to prefer soybeans until the quality of the soybean plants was diminished through feeding damage. This is the first known report of C. trifurcata feeding on cucurbits. The pest potential of C. trifurcata in cucurbit cropping systems should be further evaluated.

  2. Complete genome sequence of bean leaf crumple virus, a novel begomovirus infecting common bean in Colombia.

    Science.gov (United States)

    Carvajal-Yepes, Monica; Zambrano, Leidy; Bueno, Juan M; Raatz, Bodo; Cuellar, Wilmer J

    2017-02-10

    A copy of the complete genome of a novel bipartite begomovirus infecting common bean (Phaseolus vulgaris L.) in Colombia was obtained by rolling-circle amplification (RCA), cloned, and sequenced. The virus is associated with leaf crumple symptoms and significant yield losses in Andean and Mesoamerican beans. Such symptoms have been reported increasingly in Colombia since at least 2002, and we detected the virus in leaf material collected since 2008. Sequence analysis showed that the virus is a member of a distinct species, sharing 81% and 76% nucleotide (nt) sequence identity (in DNA-A and DNA-B, respectively) to other begomoviruses infecting common bean in the Americas. The data obtained support the taxonomic status of this virus (putatively named 'bean leaf crumple virus', BLCrV) as a member of a novel species in the genus Begomovirus.

  3. Thiol accumulation and cysteine desulfhydrase activity in H2S-fumigated leaves and leaf homogenates of cucurbit plants

    NARCIS (Netherlands)

    Schütz, Bärbel; De Kok, Luit J.; Rennenberg, Heinz

    1991-01-01

    Fumigation of both, cucurbit plants and cucurbit leaf homogenates with hydrogen sulfide (H2S) resulted in an increase in soluble thiol, mainly glutathione and cysteine. In leaf homogenates this increase was counteracted or prevented by the addition at 1 mM of inhibitors of pyridoxalphosphate depende

  4. Chloroplast dysfunction causes multiple defects in cell cycle progression in the Arabidopsis crumpled leaf mutant.

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    Hudik, Elodie; Yoshioka, Yasushi; Domenichini, Séverine; Bourge, Mickaël; Soubigout-Taconnat, Ludivine; Mazubert, Christelle; Yi, Dalong; Bujaldon, Sandrine; Hayashi, Hiroyuki; De Veylder, Lieven; Bergounioux, Catherine; Benhamed, Moussa; Raynaud, Cécile

    2014-09-01

    The majority of research on cell cycle regulation is focused on the nuclear events that govern the replication and segregation of the genome between the two daughter cells. However, eukaryotic cells contain several compartmentalized organelles with specialized functions, and coordination among these organelles is required for proper cell cycle progression, as evidenced by the isolation of several mutants in which both organelle function and overall plant development were affected. To investigate how chloroplast dysfunction affects the cell cycle, we analyzed the crumpled leaf (crl) mutant of Arabidopsis (Arabidopsis thaliana), which is deficient for a chloroplastic protein and displays particularly severe developmental defects. In the crl mutant, we reveal that cell cycle regulation is altered drastically and that meristematic cells prematurely enter differentiation, leading to reduced plant stature and early endoreduplication in the leaves. This response is due to the repression of several key cell cycle regulators as well as constitutive activation of stress-response genes, among them the cell cycle inhibitor SIAMESE-RELATED5. One unique feature of the crl mutant is that it produces aplastidic cells in several organs, including the root tip. By investigating the consequence of the absence of plastids on cell cycle progression, we showed that nuclear DNA replication occurs in aplastidic cells in the root tip, which opens future research prospects regarding the dialogue between plastids and the nucleus during cell cycle regulation in higher plants.

  5. Chloroplast Dysfunction Causes Multiple Defects in Cell Cycle Progression in the Arabidopsis crumpled leaf Mutant

    KAUST Repository

    Hudik, Elodie

    2014-07-18

    The majority of research on cell cycle regulation is focused on the nuclear events that govern the replication and segregation of the genome between the two daughter cells. However, eukaryotic cells contain several compartmentalized organelles with specialized functions, and coordination among these organelles is required for proper cell cycle progression, as evidenced by the isolation of several mutants in which both organelle function and overall plant development were affected. To investigate how chloroplast dysfunction affects the cell cycle, we analyzed the crumpled leaf (crl) mutant of Arabidopsis (Arabidopsis thaliana), which is deficient for a chloroplastic protein and displays particularly severe developmental defects. In the crl mutant, we reveal that cell cycle regulation is altered drastically and that meristematic cells prematurely enter differentiation, leading to reduced plant stature and early endoreduplication in the leaves. This response is due to the repression of several key cell cycle regulators as well as constitutive activation of stress-response genes, among them the cell cycle inhibitor SIAMESE-RELATED5. One unique feature of the crl mutant is that it produces aplastidic cells in several organs, including the root tip. By investigating the consequence of the absence of plastids on cell cycle progression, we showed that nuclear DNA replication occurs in aplastidic cells in the root tip, which opens future research prospects regarding the dialogue between plastids and the nucleus during cell cycle regulation in higher plants.

  6. Differential Cotton leaf crumple virus-VIGS-mediated gene silencing and viral genome localization in different Gossypium hirsutum genetic backgrounds

    KAUST Repository

    Idris, Ali

    2010-12-01

    A Cotton leaf crumple virus (CLCrV)-based gene silencing vector containing a fragment of the Gossypium hirsutum Magnesium chelatase subunit I was used to establish endogenous gene silencing in cotton of varied genetic backgrounds. Biolistic inoculation resulted in systemic and persistent photo-bleaching of the leaves and bolls of the seven cultivars tested, however, the intensity of silencing was variable. CLCrV-VIGS-mediated expression of green fluorescent protein was used to monitor the in planta distribution of the vector, indicating successful phloem invasion in all cultivars tested. Acala SJ-1, one of the cotton cultivars, was identified as a particularly optimal candidate for CLCrV-VIGS-based cotton reverse-genetics. © 2010 Elsevier Ltd.

  7. Chloroplast Dysfunction Causes Multiple Defects in Cell Cycle Progression in the Arabidopsis crumpled leaf Mutant1[C][W

    Science.gov (United States)

    Hudik, Elodie; Yoshioka, Yasushi; Domenichini, Séverine; Bourge, Mickaël; Soubigout-Taconnat, Ludivine; Mazubert, Christelle; Yi, Dalong; Bujaldon, Sandrine; Hayashi, Hiroyuki; De Veylder, Lieven; Bergounioux, Catherine; Benhamed, Moussa; Raynaud, Cécile

    2014-01-01

    The majority of research on cell cycle regulation is focused on the nuclear events that govern the replication and segregation of the genome between the two daughter cells. However, eukaryotic cells contain several compartmentalized organelles with specialized functions, and coordination among these organelles is required for proper cell cycle progression, as evidenced by the isolation of several mutants in which both organelle function and overall plant development were affected. To investigate how chloroplast dysfunction affects the cell cycle, we analyzed the crumpled leaf (crl) mutant of Arabidopsis (Arabidopsis thaliana), which is deficient for a chloroplastic protein and displays particularly severe developmental defects. In the crl mutant, we reveal that cell cycle regulation is altered drastically and that meristematic cells prematurely enter differentiation, leading to reduced plant stature and early endoreduplication in the leaves. This response is due to the repression of several key cell cycle regulators as well as constitutive activation of stress-response genes, among them the cell cycle inhibitor SIAMESE-RELATED5. One unique feature of the crl mutant is that it produces aplastidic cells in several organs, including the root tip. By investigating the consequence of the absence of plastids on cell cycle progression, we showed that nuclear DNA replication occurs in aplastidic cells in the root tip, which opens future research prospects regarding the dialogue between plastids and the nucleus during cell cycle regulation in higher plants. PMID:25037213

  8. Natural Occurrence of Tomato leaf curl New Delhi virus in Iranian Cucurbit Crops

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    Sara Yazdani-Khameneh

    2016-06-01

    Full Text Available The main areas for field-grown vegetable production in Iran were surveyed during the years of 2012–2014 to determine the occurrence of begomoviruses infecting these crops. A total of 787 leaf samples were collected from vegetables and some other host plants showing virus-like symptoms and tested by an enzyme-linked immunosorbent assay (ELISA using polyclonal antibodies produced against Tomato yellow leaf curl virus (TYLCV. According to the ELISA results, 81 samples (10.3% positively reacted with the virus antibodies. Begomovirus infections were confirmed by polymerase chain reaction (PCR using previously described TYLCV-specific primer pair TYLCV-Sar/TYLCV-Isr or universal primer pair Begomo-F/Begomo-R. The PCR tests using the primer pair TYLCV-Sar/TYLCV-Isr resulted in the amplification of the expected fragments of ca. 0.67-kb in size for ELISA-positive samples tested from alfalfa, pepper, spinach and tomato plants, confirming the presence of TYLCV. For one melon sample, having a week reaction in ELISA and no reaction in PCR using TYLCV-specific primers, the PCR reaction using the primer pair Begomo-F/Begomo-R resulted in the amplification fragments of the expected size of ca. 2.8 kb. The nucleotide sequences of the DNA amplicons derived from the isolate, Kz-Me198, were determined and compared with other sequences available in GenBank. BLASTN analysis confirmed the begomovirus infection of the sample and showed 99% identities with Tomato leaf curl New Delhi virus (ToLCNDV; phylogenetic analysis supported the results of the database searches. This study reports the natural occurrence of TYLCV in different hosts in Iran. Our results also reveal the emergence of ToLCNDV in Iranian cucurbit crops.

  9. TaqMan real-time PCR for detection and quantitation of squash leaf curl virus in cucurbits.

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    Kuan, Cheng-Ping; Huang, Hung-Chang; Chang, Chia-Che; Lu, Yi-Lin

    2012-02-01

    A real-time PCR assay based on the TaqMan chemistry was developed for reliable detection and quantitation of the squash leaf curl virus (SLCV) in melon and squash plants. This method was highly specific to SLCV and it was about one thousand times more sensitive than the conventional PCR method. The protocol of the real-time PCR established in this study enabled detection of as little as 10(2) copies of SLCV DNA with CP gene as the target. This TaqMan real-time PCR assay for detection and quantitation of SLCV would be a useful tool for application in quarantine and certification of SLCV in cucurbits as well as in the research of disease resistance and epidemiology.

  10. Characterization of a synergistic interaction between two cucurbit-infecting begomoviruses: Squash leaf curl virus and Watermelon chlorotic stunt virus.

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    Sufrin-Ringwald, Tali; Lapidot, Moshe

    2011-02-01

    Squash leaf curl virus (SLCV) and Watermelon chlorotic stunt virus (WmCSV) are cucurbit-infecting bipartite begomoviruses. Both viruses are found in the eastern Mediterranean basin but the effects of dual infection of both viruses on melon (Cucumis melo L.) have not been described. 'Arava' melon plants were inoculated in the greenhouse, using whiteflies, with either SLCV, WmCSV, or both. Control plants were exposed to nonviruliferous whiteflies or not exposed at all. Following inoculation, plants were transplanted to a 50-mesh insect-proof nethouse and grown until fruit maturity. The experiment was performed in two melon-growing seasons: spring, transplant in May and harvest in July; and summer, transplant in August and harvest in October. Following inoculation, SLCV-infected melon plants showed mild symptoms that disappeared with time, and there was no effect on plant height. WmCSV-infected plants developed disease symptoms that became more obvious with time, and plants were somewhat shorter than control plants in the spring but not in the summer. SLCV had no effect on yield, regardless of season. WmCSV had no statistically significant effect on yield in the spring but, in the summer, reduced yield by 22%, on average. Dual-inoculated plants showed a synergistic interaction between the two viruses. They developed disease symptoms that were more pronounced than WmCSV alone, with plants being shorter than control plants by 20 to 25% regardless of season. Moreover, the yield of dual-inoculated plants was reduced on average by 21% in the spring and 54% in the summer, and fruit appearance was adversely affected. Dual inoculation did not affect WmCSV DNA level but SLCV DNA level was increased several-fold by the presence of WmCSV.

  11. Squash leaf curl virus (SLCV): a serious disease threatening cucurbits production in Palestine.

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    Ali-Shtayeh, M S; Jamous, R M; Hussein, E Y; Mallah, O B; Abu-Zeitoun, S Y

    2014-04-01

    The incidence of squash leaf curl disease and molecular characterization of the Palestinian isolate of Squash leaf curl virus [SLCV-(PAL)] are described in this study. Symptomatic leaf samples obtained from squash (Cucurbita pepo), watermelon [Citrullus lanatus (Thunb.)], and cucumber (Cucumis sativus L.) plants were tested for SLCV-[PAL] infection by PCR and RCA. SLCV was also found to occur naturally in Chenopodium murale, Convolvulus sp, and Prosporis farcta which showed yellowing. The disease incidence was 85 % in samples collected from Nablus in summer season, while it was 98 % in samples collected from Qalqilia in autumn. On the other hand, SLCV incidence did not exceed 25 % in winter season. The full-length DNA-A and DNA-B genomes of SLCV-[PAL] were amplified and sequenced, and the sequences were deposited in the GenBank. Sequence analysis reveals that SLCV-[PAL] is closely related to other isolates from Lebanon (SLCV-LB2), Jordan (SLCV-JO), Israel (SLCV-IL), and Egypt (SLCV-EG). DNA-A of SLCV-[PAL] showed the highest nucleotide identity (99.4 %) with SLCV-JO, and SLCV-LB2, while DNA-B had the highest nucleotide identity (99.3 %) with SLCV-IL. However, following genome sequencing, it was found that due to two separate point mutations, two viral open reading frames (ORF) were altered in some SLCV Palestinian isolates. The AC2 ORF was extended by 141 nucleotides, while the AC4 ORF was extended by 36 nucleotides.

  12. Crumpling Damaged Graphene

    CERN Document Server

    Giordanelli, I; Andrade,, J S; Gomes, M A F; Herrmann, H J

    2016-01-01

    Through molecular mechanics we find that non-covalent interactions modify the fractality of crumpled damaged graphene. Pristine graphene membranes are damaged by adding random vacancies and carbon-hydrogen bonds. Crumpled membranes exhibit a fractal dimension of $ 2.71 \\pm 0.02$ when all interactions between carbon atoms are considered, and $2.30 \\pm 0.05$ when non-covalent interactions are suppressed. The transition between these two values, obtained by switching on/off the non-covalent interactions of equilibrium configurations, is shown to be reversible and independent on thermalisation. In order to explain this transition, we propose a theoretical model that is compatible with our numerical findings. Finally, we also compare damaged graphene membranes with other crumpled structures, as for instance, polymerised membranes and paper sheets, that share similar scaling properties.

  13. Contribuição das folhas cotiledonares para o crescimento e estabelecimento de plântulas de cucurbitáceas Cotyledonary leaf contribution for growth and establishment of cucurbit seedlings

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    Dilson Antônio Bisognin

    2004-06-01

    seedlings (with intact cotyledons. Initial growth was quantified at 3-day intervals, from emergence until 21 DAE, by assessing expansion rate of cotyledonary leaves, time from emergence to achieve equivalence between leaf and cotyledonary area, and total dry matter production. Squash showed the highest expansion rate of cotyledonary leaves, the shortest time to achieve equivalence between leaf and cotyledonary area, and the highest total dry matter production. Squash and cucumber seedlings showed higher dependence on cotyledonary leaves than watermelon and bottlegourd. Impairment of cotyledonary leaves, depending on species, cotiledon damage level and seedling physiological age, can drastically affect initial growth and establishment of seedlings, therefore leading to yield reductions in cucurbits.

  14. Melon chlorotic leaf curl virus: characterization and differential reassortment with closest relatives reveal adaptive virulence in the squash leaf curl virus clade and host shifting by the host-restricted bean calico mosaic virus.

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    Idris, A M; Mills-Lujan, K; Martin, K; Brown, J K

    2008-02-01

    The genome components of the Melon chlorotic leaf curl virus (MCLCuV) were cloned from symptomatic cantaloupe leaves collected in Guatemala during 2002. The MCLCuV DNA-A and DNA-B components shared their closest nucleotide identities among begomoviruses, at approximately 90 and 81%, respectively, with a papaya isolate of MCLCuV from Costa Rica. The closest relatives at the species level were other members of the Squash leaf curl virus (SLCV) clade, which is endemic in the southwestern United States and Mexico. Biolistic inoculation of cantaloupe seedlings with the MCLCuV DNA-A and -B components resulted in the development of characteristic disease symptoms, providing definitive evidence of causality. MCLCuV experimentally infected species within the Cucurbitaceae, Fabaceae, and Solanaceae. The potential for interspecific reassortment was examined for MCLCuV and its closest relatives, including the bean-restricted Bean calico mosaic virus (BCaMV), and three other cucurbit-infecting species, Cucurbit leaf crumple virus (CuLCrV), SLCV, and SMLCV. The cucurbit viruses have distinct but overlapping host ranges. All possible reassortants were established using heterologous combinations of the DNA-A or DNA-B components. Surprisingly, only certain reassortants arising from MCLCuV and BCaMV, or MCLCuV and CuLCrV, were viable in bean, even though it is a host of all of the "wild-type" (parent) viruses. The bean-restricted BCaMV was differentially assisted in systemically infecting the cucurbit test species by the components of the four cucurbit-adapted begomoviruses. In certain heterologous combinations, the BCaMV DNA-A or -B component was able to infect one or more cucurbit species. Generally, the reassortants were less virulent in the test hosts than the respective wild-type (parent) viruses, strongly implicating adaptive modulation of virulence. This is the first illustration of reassortment resulting in the host range expansion of a host-restricted begomovirus.

  15. Direct observation of the temporal and spatial dynamics during crumpling.

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    Aharoni, Hillel; Sharon, Eran

    2010-12-01

    Crumpling occurs when a thin deformable sheet is crushed under an external load or grows within a confining geometry. Crumpled sheets have large resistance to compression and their elastic energy is focused into a complex network of localized structures. Different aspects of crumpling have been studied theoretically, experimentally and numerically. However, very little is known about the dynamic evolution of three-dimensional spatial configurations of crumpling sheets. Here we present direct measurements of the configurations of a fully elastic sheet evolving during the dynamic process of crumpling under isotropic confinement. We observe the formation of a network of ridges and vertices into which the energy is localized. The network is dynamic. Its evolution involves movements of ridges and vertices. Although the characteristics of ridges agree with theoretical predictions, the measured accumulation of elastic energy within the entire sheet is considerably slower than predicted. This could be a result of the observed network rearrangement during crumpling.

  16. Differential Colonization Dynamics of Cucurbit Hosts by Erwinia tracheiphila.

    Science.gov (United States)

    Vrisman, Cláudio M; Deblais, Loïc; Rajashekara, Gireesh; Miller, Sally A

    2016-07-01

    Bacterial wilt is one of the most destructive diseases of cucurbits in the Midwestern and Northeastern United States. Although the disease has been studied since 1900, host colonization dynamics remain unclear. Cucumis- and Cucurbita-derived strains exhibit host preference for the cucurbit genus from which they were isolated. We constructed a bioluminescent strain of Erwinia tracheiphila (TedCu10-BL#9) and colonization of different cucurbit hosts was monitored. At the second-true-leaf stage, Cucumis melo plants were inoculated with TedCu10-BL#9 via wounded leaves, stems, and roots. Daily monitoring of colonization showed bioluminescent bacteria in the inoculated leaf and petiole beginning 1 day postinoculation (DPI). The bacteria spread to roots via the stem by 2 DPI, reached the plant extremities 4 DPI, and the plant wilted 6 DPI. However, Cucurbita plants inoculated with TedCu10-BL#9 did not wilt, even at 35 DPI. Bioluminescent bacteria were detected 6 DPI in the main stem of squash and pumpkin plants, which harbored approximately 10(4) and 10(1) CFU/g, respectively, of TedCu10-BL#9 without symptoms. Although significantly less systemic plant colonization was observed in nonpreferred host Cucurbita plants compared with preferred hosts, the mechanism of tolerance of Cucurbita plants to E. tracheiphila strains from Cucumis remains unknown.

  17. Edwards's statistical mechanics of crumpling networks in crushed self-avoiding sheets with finite bending rigidity.

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    Balankin, Alexander S; Flores-Cano, Leonardo

    2015-03-01

    This paper is devoted to the crumpling of thin matter. The Edwards-like statistical mechanics of crumpling networks in a crushed self-avoiding sheet with finite bending rigidity is developed. The statistical distribution of crease lengths is derived. The relationship between sheet packing density and hydrostatic pressure is established. The entropic contribution to the crumpling network rigidity is outlined. The effects of plastic deformations and sheet self-contacts on crumpling mechanics are discussed. Theoretical predictions are in good agreement with available experimental data and results of numerical simulations. Thus, the findings of this work provide further insight into the physics of crumpling and mechanical properties of crumpled soft matter.

  18. Cultivation and uses of cucurbits

    Science.gov (United States)

    Cultivated cucurbits have spread through trade and exploration from their respective Old and New World centers of origin to the six arable continents and are important in local, regional and world trade. Cucumber (Cucumis sativus L.), melon (Cucumis melo L.), pumpkin, squash and gourd (Cucurbita spp...

  19. Crumpling of an Elastic Ring in Two Dimensions

    Science.gov (United States)

    Vanhuss, Carter; Cheng, Shengfeng

    We use molecular dynamics simulations to study the crumpling of an elastic ring (i.e., a circular elastic line) in two dimensions. The crumpling is triggered by reducing the radius of a circular repulsive wall that is used to confine the ring. The ring is modeled as a bead-spring chain. A harmonic potential describing the bonds between neighboring beads is parameterized to reproduce the Young's modulus of the elastic line in the continuum limit. A modified harmonic angle interaction is used to capture the bending of the elastic line including situations where the line is locally stretched or compressed. We have confirmed that the bead-spring model has the correct continuum limit by comparing results on rings made of different numbers of beads but with parameters derived from the same elastic line. With the computational model, we study the morphological transition of the ring and the local distribution of the bond and bending energies as the ring is compressed at various rates, forced to crumple, and finally confined into a dense-packed structure. We find that the crumpling transition signals a sharp energy transfer from the compression to the bending mode. We further explore the possibility of defining an effective temperature for such crumpled systems.

  20. Assessment of Field-Grown Cucurbit Crops and Weeds within Farms in South-West Nigeria for Viral Diseases

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    Emily Ibitaiyewa AYO-JOHN

    2014-09-01

    Full Text Available Cucurbits are economic crops in Nigeria which serve as additional nutritional supplements and also good sources of income for farmers. Viral diseases are a worldwide problem of cucurbits and a major limiting factor for cucurbit production. A survey of farmer’s fields where cucurbit crops were grown was carried out to assess the incidence and severity of virus symptoms and viruses associated with the crops and weeds in selected locations in Ogun and Osun, in southwest Nigeria, in June, 2012. In all, 38 leaf samples were collected in Ogun state and 52 in Osun state from cucurbit crops and weeds. Leaf samples were tested against  Cucumber mosaic virus (CMV, Melon necrotic spot virus (MNSV, Papaya ringspot virus (PRSV, Watermelon mosaic virus (WMV,Zucchini yellow mosaic virus (ZYMV and Cucumber green mottle mosaic virus (CGMMV using Double Antibody Sandwich (DAS enzyme-linked immunosorbent assay (ELISA. All the fields surveyed had virus symptom incidences of 100% except for melon fields in Osun state with incidences of between 10 and 30%. In Ogun state, the occurrence of CMV was 5/31 (16.1% while MNSV was detected in Lagenaria siceraria and T. occidentalis and it occurred in 6.5% of the leaf samples. In Osun state, CMV was detected in watermelon, melon and weeds found in all locations surveyed. The occurrence of CMV was 9/38 (23.7% in the cucurbit crops and in 78.6% (11/14 of the weeds. PRSV and WMV also occurred in mixed infection with CMV in 7.1% respectively. CMV was the most widespread and prevalent virus infecting cucurbit crops and weeds.Cucurbits are economic crops in Nigeria which serve as additional nutritional supplements and also good sources of income for farmers. Viral diseases are a worldwide problem of cucurbits and a major limiting factor for cucurbit production. A survey of farmer’s fields where cucurbit crops were grown was carried out to assess the incidence and severity of virus symptoms and viruses associated with the crops

  1. Crumpled Graphene Photodetector with Enhanced, Strain-Tunable, and Wavelength-Selective Photoresponsivity.

    Science.gov (United States)

    Kang, Pilgyu; Wang, Michael Cai; Knapp, Peter M; Nam, SungWoo

    2016-06-01

    A stretchable photodetector with enhanced, strain-tunable photoresponsivity is developed based on crumpled graphene by engineering 2D graphene into 3D structures. This crumpled graphene photodetector demonstrates ≈400% enhanced photoresponsivity led by an order-of-magnitude enhanced extinction of graphene and 100% modulation in photoresponsivity with 200% applied strain. Finally, strain-tunable, wavelength-selective photodetection is shown by integrated colloidal photonic crystals-crumpled graphene photodetector devices.

  2. Host Selection, Growth, and Survival of Melonworm (Lepidoptera: Crambidae) on Four Cucurbit Crops Under Laboratory Conditions

    Science.gov (United States)

    Panthi, B. R.; Seal, D. R.; Capinera, J. L.; Nuessly, G. S.; Martin, C. G.

    2016-01-01

    The melonworm, Diaphania hyalinata L. (Lepidoptera: Crambidae), is one of the most serious insect problems affecting cucurbit production. We evaluated the relative preference and suitability of yellow squash, zucchini, cucumber, and watermelon to melonworm by measuring its oviposition, larval feeding preference, survivorship, and developmental responses in the laboratory. Whole plants were used for oviposition study, whereas host leaf discs were used for all the other studies. Watermelon feeding resulted in the longest larval development period (14.3 d), greatest prepupal weights and survivals rates (92%; first instar to adult) among the four crops. However, for watermelon, adult oviposition preference (199.5 eggs/♀), egg survival (70%), and larval feeding (4.1% defoliation) were numerically or statistically lowest, and larval head capsule widths and whole-body lengths were smallest. When differences occurred among these variables, yellow squash, zucchini, and cucumber were each typically higher (or quicker to develop) than watermelon. So why do melonworm adults not prefer watermelon, or at least select it as frequently as squash and cucumber when ovipositing? The answer likely is that there might be some variation in the important chemical components among these cucurbits. We suggest that comparison of kairomones and allomones from watermelon and related cucurbits would be very useful for determining the combination resulting in the lowest risk of damage to the more susceptible cucurbits (assuming the levels can be modified without seriously affecting the crops). PMID:27400704

  3. Controlled Buckling and Crumpling of Nanoparticle-Coated Droplets

    OpenAIRE

    Datta, Sujit S.; Shum, Ho Cheung; Weitz, David A.

    2010-01-01

    We introduce a new experimental approach to study the structural transitions of large numbers of nanoparticle-coated droplets as their volume is reduced. We use an emulsion system where the dispersed phase is slightly soluble in the continuous phase. By adding a fixed amount of unsaturated continuous phase, the volume of the droplets can be controllably reduced, causing them to buckle or crumple, thereby becoming nonspherical. The resultant morphologies depend both on the extent of volume red...

  4. Unpacking of a Crumpled Wire from Two-Dimensional Cavities.

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    Thiago A Sobral

    Full Text Available The physics of tightly packed structures of a wire and other threadlike materials confined in cavities has been explored in recent years in connection with crumpled systems and a number of topics ranging from applications to DNA packing in viral capsids and surgical interventions with catheter to analogies with the electron gas at finite temperature and with theories of two-dimensional quantum gravity. When a long piece of wire is injected into two-dimensional cavities, it bends and originates in the jammed limit a series of closed structures that we call loops. In this work we study the extraction of a crumpled tightly packed wire from a circular cavity aiming to remove loops individually. The size of each removed loop, the maximum value of the force needed to unpack each loop, and the total length of the extracted wire were measured and related to an exponential growth and a mean field model consistent with the literature of crumpled wires. Scaling laws for this process are reported and the relationship between the processes of packing and unpacking of wire is commented upon.

  5. Unpacking of a Crumpled Wire from Two-Dimensional Cavities.

    Science.gov (United States)

    Sobral, Thiago A; Gomes, Marcelo A F; Machado, Núbia R; Brito, Valdemiro P

    2015-01-01

    The physics of tightly packed structures of a wire and other threadlike materials confined in cavities has been explored in recent years in connection with crumpled systems and a number of topics ranging from applications to DNA packing in viral capsids and surgical interventions with catheter to analogies with the electron gas at finite temperature and with theories of two-dimensional quantum gravity. When a long piece of wire is injected into two-dimensional cavities, it bends and originates in the jammed limit a series of closed structures that we call loops. In this work we study the extraction of a crumpled tightly packed wire from a circular cavity aiming to remove loops individually. The size of each removed loop, the maximum value of the force needed to unpack each loop, and the total length of the extracted wire were measured and related to an exponential growth and a mean field model consistent with the literature of crumpled wires. Scaling laws for this process are reported and the relationship between the processes of packing and unpacking of wire is commented upon.

  6. Identification, distribution and incidence of viruses in field-grown cucurbit crops of Iran

    Directory of Open Access Journals (Sweden)

    K. Bananej

    2009-01-01

    Full Text Available A survey of viruses in the major cucurbit-growing areas of 17 provinces in Iran was conducted in 2005 and 2006. A total of 1699 leaf samples were collected from melon, squash, cucumber and watermelon plants showing various virus-like symptoms. Screening for 11 cucurbit viruses by double-antibody sandwich ELISA (DAS-ELISA or RT-PCR, found that 71% of the samples were infected by at least one virus, of which Cucurbit aphid-borne yellows virus (CABYV was the most common overall, occurring in 49, 47, 40, and 33% of cucumber, squash, melon, and watermelon samples respectively. The second most common virus on melon and watermelon was Watermelon mosaic virus (WMV (incidence 30–33%; on cucumber, Cucumber mosaic virus (CMV(33%; and on squash, Zucchini yellow mosaic virus (ZYMV(38%. To our knowledge, this is the first report of Melon necrotic spot virus (MNSV and Zucchini yellow fl eck virus (ZYFV in Iran. Mixed infections occurred in 49% of symptomatic samples. Mixed infections were relatively frequent in squash (58% and melon (55%. The most frequent double infections were WMV+CABYV and ZYMV+CABYV in melon, squash and cucumber, followed by WMV+ZYMV. In watermelon, the most frequent double infection was WMV+ZYMV, followed by WMV+CABYV. The high frequency of CABYV, WMV and ZYMV in the samples assayed on all four cucurbit crops and in all areas surveyed, as well as the detection of Watermelon chlorotic stunt virus (WmCSV and Cucumber vein yellowing virus (CVYV in northern and southern Iran, suggest that these viruses represent a potential threat to cucurbit crops in Iran.

  7. Characterization of the small RNA component of leaves and fruits from four different cucurbit species

    Directory of Open Access Journals (Sweden)

    Jagadeeswaran Guru

    2012-07-01

    Full Text Available Abstract Background MicroRNAs (miRNAs are a class of non-coding small RNAs involved in post-transcriptional regulation of gene expression critical for plant growth and development, stress responses and other diverse biological processes in plants. The Cucurbitaceae or cucurbit family represents some of economically important species, particularly those with edible and medicinal fruits. Genomic tools for the molecular analysis of members of this family are just emerging. Partial draft genome sequence became available recently for cucumber and watermelon facilitating investigation of the small RNA component of the transcriptomes in cucurbits. Results We generated four small RNA libraries from bottle gourd (Lagenaria siceraria, Cucurbita moschata, Cucurbita pepo, and, watermelon (Citrullus lanatus var. lanatus in order to identify conserved and novel lineage specific miRNAs in these cucurbits. Deep sequencing of small RNA libraries from these species resulted in 1,597,263, 532,948, 601,388, and 493,384 unique sRNA reads from bottle gourd, moschata, pepo and watermelon, respectively. Sequence analysis of these four libraries resulted in identification of 21 miRNA families that are highly conserved and 8 miRNA families that are moderately conserved in diverse dicots. We also identified 4 putative novel miRNAs in these plant species. Furthermore, the tasiRNAs were identified and their biogenesis was determined in these cucurbits. Small RNA blot analysis or q-PCR analyses of leaf and fruit tissues of these cucurbits showed differential expression of several conserved miRNAs. Interestingly, the abundance of several miRNAs in leaves and fruits of closely related C. moschata and C. pepo was also distinctly different. Target genes for the most conserved miRNAs are also predicted. Conclusion High-throughput sequencing of small RNA libraries from four cucurbit species has provided a glimpse of small RNA component in their transcriptomes. The analysis also

  8. Crumpling of graphene oxide through evaporative confinement in nanodroplets produced by electrohydrodynamic aerosolization

    Science.gov (United States)

    Kavadiya, Shalinee; Raliya, Ramesh; Schrock, Michael; Biswas, Pratim

    2017-02-01

    Restacking of graphene oxide (GO) nanosheets results in loss of surface area and creates limitations in its widespread use for applications. Previously, two-dimensional (2D) GO sheets have been crumpled into 3D structures to prevent restacking using different techniques. However, synthesis of nanometer size crumpled graphene particles and their direct deposition onto a substrate have not been demonstrated under room temperature condition so far. In this work, the evaporative crumpling of GO sheets into very small size (mobility particle sizer (SMPS) and off-line using electron microscopy. The relation between the confinement force and the factors affecting the crumpled structure is established. Furthermore, to expand the application horizons of the structure, crumpled GO-TiO2 nanocomposites are synthesized. The method described here allows a simple and controlled production of graphene-based particles/composites with direct deposition onto any kind of substrate for a variety of applications.

  9. Occurrence, Distribution and Biological variability of Zucchini Yellow Mosaic Virus in cucurbits of Khuzestan province, South west of Iran

    Directory of Open Access Journals (Sweden)

    Somayeh Safara

    2011-11-01

    Full Text Available ZYMV is one of the most important plant viruses that cause economical damage in cucurbits. The symptoms of ZYMV in different cucurbits include stunting, yellowing, mottling, severe mosaic, leaf and fruit deformation, blistering and shoe string. Investigation on occurrence of this virus, in Khuzestan province was carried out in November 2009, April and May 2010 by collecting cucurbits samples from different cucurbits fields. After DAS-ELISA test, ZYMV was maintained in squash. Then total RNA were extracted and were tested by RT-PCR. Using RT-PCR, fragments belonging to N-terminal of coat protein and C-terminal of nuclear inclusion bodies were replicated. PCR product for investigation of replication was loaded in 1% agarose gel. From seven regions in Khuzestan, 175 leaf samples showing different symptoms (yellowing, mosaic, deformation and blistering were collected. Seventy one samples out of total samples (175 samples showed ZYMV infection. Occurrence of Zucchini Yellow Mosaic Virus in Khuzestan province was confirmed, using serological and RT-PCR tests. Infection of ZYMV in Khuzestan province (40.5% is higher than the average of Iran’s infection (38%. This article is first report of occurrence ZYMV in different regions of Khuzestan province except Dezful.

  10. Scaling, crumpled wires, and genome packing in virions

    Science.gov (United States)

    de Holanda, V. H.; Gomes, M. A. F.

    2016-12-01

    The packing of a genome in virions is a topic of intense current interest in biology and biological physics. The area is dominated by allometric scaling relations that connect, e.g., the length of the encapsulated genome and the size of the corresponding virion capsid. Here we report scaling laws obtained from extensive experiments of packing of a macroscopic wire within rigid three-dimensional spherical and nonspherical cavities that can shed light on the details of the genome packing in virions. We show that these results obtained with crumpled wires are comparable to those from a large compilation of biological data from several classes of virions.

  11. Cucurbits [Cucumber, melon, pumpkin and squash

    Science.gov (United States)

    The focus of this chapter is on the edible members of the Cucurbitaceae family. The three important food-grade cucurbit genera Citrullus, Cucumis, and Cucurbita include the species Citrullus lanatus watermelons), Cucumis melo (cantaloupes and other sweet melons), Cucumis sativa (cucumbers and pick...

  12. Occurrence and distribution of ten viruses infecting cucurbit plants in Guilan province, Iran.

    Science.gov (United States)

    Gholamalizadeh, R; Vahdat, A; Keshavarz, T; Elahinia, A; Bananej, K

    2008-01-01

    During the 2006 and 2007 growing seasons, a systematic survey was conducted in open-field of melon (Cucumis melo L.), cucumber (C. sativus L.), squash (Cucurbita sp.), and watermelon (Citrulus lanatus L.) crops in 16 major cucurbit-growing areas of Guilan province in Iran. Symptomatic leaf samples were collected and screened by double-antibody sandwich ELISA (DAS-ELISA) or RT-PCR to detect Zucchini yellow mosaic virus (ZYMV), Watermelon mosaic virus (WMV), Cucurbit aphid-borne yellows virus (CABYV), Cucumber mosaic virus (CMV), Squash mosaic virus (SqMV), Papaya ringspot virus type W (PRSV-W), Watermelon chlorotic stunt virus (WmCSV), Melon necrotic spot virus (MNSV), Zucchini yellow fleck virus (ZYFV), and Ourmia melon virus (OuMV). The majority of tested samples (73.7%) were infected by at least one of the viruses considered. OuMV, ZYMV, WMV, and WmCSV were the most prevalent viruses and were detected in tested cucurbit plants. The incidence of multiple infections with 2 or more viruses was also relatively high, 63.3, 48.6, 42.7, and 26.7% of the infected samples of melon, cucumber, squash, and watermelon, respectively. The high incidence of OuMV and WmCSV suggested that these viruses might turn out to be an important threat for the melon and cucumber crops in the province.

  13. Identification of viruses infecting cucurbits and determination of genetic diversity of Cucumber mosaic virus in Lorestan province, Iran

    Directory of Open Access Journals (Sweden)

    Hasanvand Vahid

    2017-06-01

    Full Text Available Various viral pathogens infect Cucurbitaceae and cause economic losses. The aim of the present study was to detect plant viral pathogens including Cucumber mosaic virus (CMV, Cucumber green mottle mosaic virus (CGMMV, Zucchini yellow mosaic virus (ZYMV, Cucurbit yellow stunting disorder virus (CYSDV and Cucurbit chlorotic yellows virus (CCYV in Lorestan province, in western Iran, and also to determine CMV genetic diversity in Iranian populations. A total of 569 symptomatic leaf samples were collected in 2013 and 2014 from cucurbits growing regions in Lorestan province. The collected samples were assessed for viral diseases by ELISA. The results showed virus incidences in most regions. Then, the infection of 40 samples to CMV was confirmed by RT-PCR. Moreover, to distinguish between the two groups (I and II of CMV, PCR products were digested by two restriction enzymes XhoI and EcoRI. Results of the digestion showed that the isolates of Lorestan belonged to group I. The CMV-coat protein gene of eight isolates from different regions and hosts was sequenced and phylogenetic analysis was performed. Subsequent analyses showed even more genetic variation among Lorestan isolates. The phylogenetic tree revealed that Lorestan province isolates belonged to two IA and IB subgroups and could be classified together with East Azerbaijan province isolates. The results of the present study indicate a wide distribution of CMV, ZYMV, CGMMV, CYSDV and CCYV viruses in cucurbits fields of Lorestan province and for the first time subgroup IB of CMV was reported on melon from Iran.

  14. Self-dispersed crumpled graphene balls in oil for friction and wear reduction

    Science.gov (United States)

    Dou, Xuan; Koltonow, Andrew R.; He, Xingliang; Jang, Hee Dong; Wang, Qian; Chung, Yip-Wah; Huang, Jiaxing

    2016-01-01

    Ultrafine particles are often used as lubricant additives because they are capable of entering tribological contacts to reduce friction and protect surfaces from wear. They tend to be more stable than molecular additives under high thermal and mechanical stresses during rubbing. It is highly desirable for these particles to remain well dispersed in oil without relying on molecular ligands. Borrowing from the analogy that pieces of paper that are crumpled do not readily stick to each other (unlike flat sheets), we expect that ultrafine particles resembling miniaturized crumpled paper balls should self-disperse in oil and could act like nanoscale ball bearings to reduce friction and wear. Here we report the use of crumpled graphene balls as a high-performance additive that can significantly improve the lubrication properties of polyalphaolefin base oil. The tribological performance of crumpled graphene balls is only weakly dependent on their concentration in oil and readily exceeds that of other carbon additives such as graphite, reduced graphene oxide, and carbon black. Notably, polyalphaolefin base oil with only 0.01–0.1 wt % of crumpled graphene balls outperforms a fully formulated commercial lubricant in terms of friction and wear reduction. PMID:26811466

  15. Mechanical properties in crumple-formed paper derived materials subjected to compression

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    D.A.H. Hanaor

    2017-06-01

    Full Text Available The crumpling of precursor materials to form dense three dimensional geometries offers an attractive route towards the utilisation of minor-value waste materials. Crumple-forming results in a mesostructured system in which mechanical properties of the material are governed by complex cross-scale deformation mechanisms. Here we investigate the physical and mechanical properties of dense compacted structures fabricated by the confined uniaxial compression of a cellulose tissue to yield crumpled mesostructuring. A total of 25 specimens of various densities were tested under compression. Crumple formed specimens exhibited densities in the range 0.8–1.3 g cm−3, and showed high strength to weight characteristics, achieving ultimate compressive strength values of up to 200 MPa under both quasi-static and high strain rate loading conditions and deformation energy that compares well to engineering materials of similar density. The materials fabricated in this work and their mechanical attributes demonstrate the potential of crumple-forming approaches in the fabrication of novel energy-absorbing materials from low-cost precursors such as recycled paper. Stiffness and toughness of the materials exhibit density dependence suggesting this forming technique further allows controllable impact energy dissipation rates in dynamic applications.

  16. Crumpling deformation regimes of monolayer graphene on substrate: a molecular mechanics study.

    Science.gov (United States)

    Al-Mulla, Talal; Qin, Zhao; Buehler, Markus J

    2015-09-04

    Experiments and simulations demonstrating reversible and repeatable crumpling of graphene warrant a detailed understanding of the underlying mechanisms of graphene crumple formation, especially for design of tailored nanostructures. To systematically study the formation of crumples in graphene, we use a simple molecular dynamics model, and perform a series of simulations to characterize the finite number of deformation regimes of graphene on substrate after compression. We formulate a quantitative measure of predicting these deformations based on observed results of the simulations and distinguish graphene crumpling considered in this study from others. In our study, graphene is placed on a model substrate while controlling and varying the interfacial energy between graphene and substrate and the substrate roughness through a set of particles embedded in the substrate. We find that a critical value of interfacial adhesion energy marks a transition point that separates two deformation regimes of graphene on substrate under uniaxial compression. The interface between graphene and substrate plays a major role in the formation of crumples, and we show that the choice of substrate can help in designing desired topologies in graphene.

  17. From chromosome crumpling to the interacting randomly branched polymers

    Science.gov (United States)

    Everaers, Ralf

    The conformational statistics of ring polymers in melts or dense solutions is strongly affected by their quenched microscopic topological state. The effect is particularly strong for non-concatenated unknotted rings, which are known to crumple and segregate and which have been implicated as models for the generic behavior of interphase chromosomes. In we have used a computationally efficient multi-scale approach to identify the subtle physics underlying their behavior, where we combine massive Molecular Dynamics simulations on the fiber level with Monte Carlo simulations of a wide range of lattice models for the large scale structure. This allowed us to show that ring melts can be quantitatively mapped to coarse-grained melts of interacting randomly branched primitive paths. To elucidate the behavior of interacting branched polymers, we use a combination of scaling arguments and computer simulations. The simulations are carried out for different statistical ensembles: ideal randomly branching polymers, melts of interacting randomly branching polymers, and self-avoiding trees with annealed and quenched connectivities. In all cases, we perform a detailed analysis of the tree connectivities and conformations. We find that the scaling behaviour of average properties is very well described by the Flory theory of Gutin et al. [Macromolecules 26, 1293 (1993)]. A detailed study of the corresponding distribution functions allows us to propose a coherent framework of the behavior of interacting trees, including generalised Fisher-Pincus relationships and the detailed analysis of contacts statistics.

  18. Microscopically crumpled indium-tin-oxide thin films as compliant electrodes with tunable transmittance

    Energy Technology Data Exchange (ETDEWEB)

    Ong, Hui-Yng [School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798 (Singapore); School of Engineering, Nanyang Polytechnic, Singapore 569830 (Singapore); Shrestha, Milan; Lau, Gih-Keong, E-mail: mgklau@ntu.edu.sg [School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

    2015-09-28

    Indium-tin-oxide (ITO) thin films are perceived to be stiff and brittle. This letter reports that crumpled ITO thin films on adhesive poly-acrylate dielectric elastomer can make compliant electrodes, sustaining compression of up to 25% × 25% equi-biaxial strain and unfolding. Its optical transmittance reduces with crumpling, but restored with unfolding. A dielectric elastomer actuator (DEA) using the 14.2% × 14.2% initially crumpled ITO thin-film electrodes is electrically activated to produce a 37% areal strain. Such electric unfolding turns the translucent DEA to be transparent, with transmittance increased from 39.14% to 52.08%. This transmittance tunability promises to make a low-cost smart privacy window.

  19. NMR study on self-assembled cage complex of hexamethylenetetramine and cucurbit[n]urils

    Institute of Scientific and Technical Information of China (English)

    SHEN Yongqiang; XUE Saifeng; ZHAO Yunjie; ZHU Qianjiang; TAO Zhu

    2003-01-01

    Self-assembled complexes between cage compounds cucurbit[n = 5-8]urils and hexamethylenetetramine were studied by using NMR techniques. Experimental results reveal that hexamethylenetetramine can lid cucurbit[5]uril to forming self-assembled capsules in which nothing is encapsulated yet; the cavity of the cucurbit[7]uril can accommodate a hexamethylenetetramine molecule to form a self- assembled host-guest inclusion. Moreover, both the cavity interaction of the cucurbit[7]uril with hexamethylenetetramine·HCl and the portal interaction of the dipole carbonyl of the cucurbit[7]uril with hexamethylenetetramine·HCl lead to form self-assembled capsules in which the hexamethylenetetramine·HCl are encapsulated in the hexamethylenetetramine·HCl "lidded" cucurbit[7]uril. Although the structures of the portal and cavity to cucurbit[5]uril are similar, there is no obvious interaction between decamethylcucurbit[5]uril and hexamethylenetetramine, and also between cucurbit [6]uril or cucurbit[8]uril and hexamethylenetetramine.

  20. Complexation behavior of cucurbit[6]uril with short polypeptides

    Energy Technology Data Exchange (ETDEWEB)

    Buschmann, Hans-Juergen [Deutsches Textilforschungszentrum Nord-West e.V., Adlerstrasse 1, D-47798 Krefeld (Germany)]. E-mail: buschmann@dtnw.de; Mutihac, Lucia [University of Bucharest, Department of Analytical Chemistry, 4-12 Blvd. Regina Elisabeta, 703461 Bucharest (Romania); Mutihac, Radu-Cristian [Deutsches Textilforschungszentrum Nord-West e.V., Adlerstrasse 1, D-47798 Krefeld (Germany); Schollmeyer, Eckhard [Deutsches Textilforschungszentrum Nord-West e.V., Adlerstrasse 1, D-47798 Krefeld (Germany)

    2005-06-15

    The binding properties of cucurbit[6]uril towards various peptides have been investigated in acidic aqueous solution. Stability constants and thermodynamic values of the complex formation between following peptides: glycyl-L-alanine, L-leucyl-L-valine, glycyl-L-asparagine, L-leucyl-L-phenylalanine, L-leucyl-L-tryptophan, glycyl-L-histidine, L-glutathione reduced ({gamma}-L-glutamyl-L-cysteinyl-glycine, GSH), and DL-leucyl-glycyl-DL-phenylalanine) with cucurbit[6]uril in aqueous formic acid (50%, v/v) have been calculated from calorimetric titrations. From these results it can be seen that the peptides form exclusion complexes with cucurbit[6]uril. Due to the polar peptide bond they are not included within the hydrophobic cavity of cucurbit[6]uril. The complex formation is favoured by entropic contributions. The release of water molecules from the polar amino groups of the peptides and the carbonyl groups of cucurbituril are responsible.

  1. Applying imidacloprid via a precision banding system to control striped cucumber beetle (Coleoptera: Chrysomelidae) in cucurbits.

    Science.gov (United States)

    Jasinski, J; Darr, M; Ozkan, E; Precheur, R

    2009-12-01

    The striped cucumber beetle, Acalymma vittatum (F.) (Coleoptera: Chrysomelidae), is a key pest of cucurbit crops throughout its range. A novel precision band applicator was designed to inject a solid stream of imidacloprid solution in-furrow directly over the seed during planting to reduce beetle leaf feeding on pumpkin, zucchini, and cucumber crops. In 2004 and 2005, bioassays at the cotyledon through fifth leaf were conducted on striped cucumber beetles using seedling leaf tissue grown from seeds treated using both continuous and precision banded in-furrow imidacloprid solution applications. In 2004, 80% of bioassay trials had treatments with beetle mortality significantly higher than the check, whereas 70% of the bioassay trials showed no significant difference in mortality between continuous in-furrow and precision banded treatments. In 2005, 79% of bioassay trials had treatments with beetle mortality significantly higher than the check, whereas 100% of the bioassays showed no significant difference in beetle mortality between continuous in-furrow and precision banded treatments at the same insecticide rate. The environmental savings of precision banded treatments compared with continuous in-furrow treatment reduced imidacloprid up to 84.5% on a per hectare basis for all cucurbits tested in 2004 and 2005, translating into an economic savings up to $215/ha. In separate bioassay trials conducted in 2005 on pumpkin, where insecticide band length and injection volume were manipulated independently, several treatments had significantly higher beetle mortality than the check. There was a trend of increased beetle mortality in treatments using shorter band lengths combined with higher insecticide solution volumes.

  2. Survey on The Occurrence of Viruses Infecting Cucurbits in Yogyakarta and Central Java

    Directory of Open Access Journals (Sweden)

    Budi Setiadi Daryono

    2009-12-01

    Full Text Available Cucurbits are grown throughout the Java Island as dry season crops. Plants having mosaic, mottling, chlorosis and leaf distortion symptoms were frequently found in most of the cucurbit fields during the survey which conducted in Central Java including Sleman, Kulon Progo, and Klaten during July–September 2000 and 2001. Using double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA; Cucumber mosaic virus (CMV, Cucumber green mottle mosaic virus (CGMMV and Kyuri green mottle mosaic virus (KGMMV were found infecting cucurbits. CMV was widespread, infecting 48.9% of the samples tested followed by CGMMV (12.8% and KGMMV (6.4%, while others samples (31.9% were not tested, double infections were common with 8.5 % of the samples being infected with two viruses (CGMMV and KGMMV and 34% with three viruses (CMV, CGMMV, and KGMMV. Severe mosaic and mottle symptoms were associated most often with single infection of CGMMV and KGMMV respectively. In addition, these are the first detections of CGMMV and KGMMV infecting cucurbit plants in Indonesia. Tanaman labu-labuan umumnya tumbuh sepanjang musim kemarau diPulau Jawa. Tanaman labu-labuan dengan gejala mosaik, klorosis, mottling dan bentuk daun serta buah yang berubah banyak dijumpai selama survei yang dilakukan di Kulon Progo, Sleman dan Klaten pada bulan Juli sampai September tahun 2000 dan 2001. Deteksi menggunakan metode double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA telah berhasil mengetahui keberadaan dan infeksiCucumber mosaic virus(CMV,Cucumber green mottle mosaic virus (CGMMV dan Kyuri green mottle mosaic virus (KGMMV pada tanaman labu-labuan di tiga kabupaten tersebut. CMV menginfeksi tanaman labu-labuan tinggi yaitu 48,9% dari jumlah sampel tanaman yang dikoleksi, kemudian CGMMV (12,8% dan KGMMV(6,4%, sedangkan sebanyak 14 sampel tanaman (31,9%tidak dideteksi.Infeksi ganda banyak ditemukan dan 8,5 % sampel tanaman terinfeksi oleh dua jenis virus (CGMMV dan

  3. Three-Dimensional Crumpled Reduced Graphene Oxide/MoS2 Nanoflowers: A Stable Anode for Lithium-Ion Batteries.

    Science.gov (United States)

    Xiong, Fangyu; Cai, Zhengyang; Qu, Longbing; Zhang, Pengfei; Yuan, Zefang; Asare, Owusu Kwadwo; Xu, Wangwang; Lin, Chao; Mai, Liqiang

    2015-06-17

    Recently, layered transition-metal dichalcogenides (TMDs) have gained great attention for their analogous graphite structure and high theoretical capacity. However, it has suffered from rapid capacity fading. Herein, we present the crumpled reduced graphene oxide (RGO) decorated MoS2 nanoflowers on carbon fiber cloth. The three-dimensional framework of interconnected crumpled RGO and carbon fibers provides good electronic conductivity and facile strain release during electrochemical reaction, which is in favor of the cycling stability of MoS2. The crumpled RGO decorated MoS2 nanoflowers anode exhibits high specific capacity (1225 mAh/g) and excellent cycling performance (680 mAh/g after 250 cycles). Our results demonstrate that the three-dimensional crumpled RGO/MoS2 nanoflowers anode is one of the attractive anodes for lithium-ion batteries.

  4. Anticancer and anti-inflammatory activities of some dietary cucurbits.

    Science.gov (United States)

    Sharma, Dhara; Rawat, Indu; Goel, H C

    2015-04-01

    In this study, we investigated few dietary cucurbits for anticancer activity by monitoring cytotoxic (MTT and LDH assays), apoptotic (caspase-3 and annexin-V assays), and also their anti-inflammatory effects by IL-8 cytokine assay. Aqua-alcoholic (50:50) whole extracts of cucurbits [Lagenaria siceraria (Ls), Luffa cylindrica (Lc) and Cucurbita pepo (Cp)] were evaluated in colon cancer cells (HT-29 and HCT-15) and were compared with isolated biomolecule, cucurbitacin-B (Cbit-B). MTT and LDH assays revealed that the cucurbit extracts and Cbit-B, in a concentration dependent manner, decreased the viability of HT-29 and HCT-15 cells substantially. The viability of lymphocytes was, however, only marginally decreased, yielding a potential advantage over the tumor cells. Caspase-3 assay revealed maximum apoptosis with Ls while annexin V assay demonstrated maximum efficacy of Lc in this context. These cucurbits have also shown decreased secretion of IL-8, thereby revealing their anti-inflammatory capability. The results have demonstrated the therapeutic potential of dietary cucurbits in inhibiting cancer and inflammatory cytokine.

  5. Bowel perforation by crumpled paper in a patient presenting with acute abdominal pain

    Directory of Open Access Journals (Sweden)

    Bakhshaeekia Alireza

    2009-01-01

    Full Text Available Many of the abdominal foreign bodies are due to accidental ingestion. Our objective in this case report is to emphasize the importance of the enquiry about the foreign body in the differential diagnosis of acute abdominal pain. According to our knowledge, this is the first report of bowel perforation caused by paper ingestion. A 14-year-old boy with abdominal pain underwent exploratory laparotomy and was found to have abdominal pus and ileal perforation. A crumpled paper was found at the site of perforation. Postoperative enquiry revealed that the patient had ingested 10 crumpled papers. We highlight that recording the history is an important aspect in the management of patients with acute abdominal pain and that foreign bodies should be included in its differential diagnosis.

  6. Crumple: An Efficient Tool to Explore Thoroughly the RNA Folding Landscape.

    Science.gov (United States)

    Guerra, Ivan; Schroeder, Susan J

    2016-01-01

    The folding landscape for an RNA sequence contains many diverse structures and motifs, which are often sampled rather than completely explored. Today's supercomputers make the complete enumeration of all possible folds for an RNA and a detailed description of the RNA folding landscape a more feasible task. This chapter provides protocols for using the Crumple folding algorithm, an efficient tool to generate all possible non-pseudoknotted folds for an RNA sequence. Crumple in conjunction with Sliding Windows and Assembly can incorporate experimental constraints on the global features of an RNA, such as the minimum number and lengths of helices, which may be determined by crystallography or cryo-electron microscopy. This complete enumeration method is independent of free-energy minimization and allows the user to incorporate experimental data such as chemical probing, SELEX data on RNA-protein binding motifs, and phylogenetic covariation.

  7. Crumpled graphene-molybdenum oxide composite powders: preparation and application in lithium-ion batteries.

    Science.gov (United States)

    Choi, Seung Ho; Kang, Yun Chan

    2014-02-01

    Crumpled graphene-MoO2 composite powders are directly prepared by means of spray pyrolysis and from a stable graphene oxide colloidal solution in the presence of Mo ions. The crumpled graphene-MoO2 composite powders are transformed into MoO3 -based composite powders after post-treatment at 300 °C. The transmission electron microscopy and dot-mapping images of the post-treatment composite powders show uniform distribution of MoO3 nanocrystals in the crumpled graphene powders. The two typical D and G bands of graphene are observed at 1350 and 1590 cm(-1) , respectively, in the Raman spectrum of the graphene-MoO3 composite. In addition, the crumpled graphene-MoO3 powders exhibit superior electrochemical behavior compared to that of pure MoO3 as an anode material for lithium-ion batteries. The initial discharge capacities of the graphene-MoO3 composite and bare MoO3 powders at a current density of 2 A g(-1) are 1490 and 1225 mA h g(-1) , respectively. The capacity retention of the graphene-MoO3 composite is 87 % after the first cycle, whereas that of bare MoO3 is 47 %, as measured after 100 cycles. The reversible discharge capacity of the graphene-MoO3 composite decreases slightly from 1228 to 845 mA h g(-1) as the current density increases from 0.5 to 3 A g(-1) .

  8. Wrinkled, rippled and crumpled graphene: an overview of formation mechanism, electronic properties, and applications

    Directory of Open Access Journals (Sweden)

    Shikai Deng

    2016-05-01

    Full Text Available Distinctive from their 1D and 0D counterparts, 2D nanomaterials (2DNs exhibit surface corrugations (wrinkles and ripples and crumples. Thermal vibrations, edge instabilities, thermodynamically unstable (interatomic interactions, strain in 2D crystals, thermal contraction, dislocations, solvent trapping, pre-strained substrate-relaxation, surface anchorage and high solvent surface tension during transfer cause wrinkles or ripples to form on graphene. These corrugations on graphene can modify its electronic structure, create polarized carrier puddles, induce pseudomagnetic field in bilayers and alter surface properties. This review outlines the different mechanisms of wrinkle, ripple and crumple formation, and the interplay between wrinkles’ and ripples’ attributes (wavelength/width, amplitude/height, length/size, and bending radius and graphene's electronic properties and other mechanical, optical, surface, and chemical properties. Also included are brief discussions on corrugation-induced reversible wettability and transmittance in graphene, modulation of its chemical potential, enhanced energy storage and strain sensing via relaxation of corrugations. Finally, the review summarizes the future areas of research for 2D corrugations and crumples.

  9. Recessive resistance to Cucurbit yellow stunting disorder virus in melon

    Science.gov (United States)

    Cucurbit yellow stunting disorder virus (CYSDV) reduces melon (Cucumis melo L.) fruit quality and yield in many parts of the world. CYSDV and its vector, sweetpotato whitefly (MEAM1 cryptic species of Bemisia tabaci; SPWF) are a devastating combination in the Sonoran Desert areas of California and A...

  10. New Sources of Resistance to Cucurbit Powdery Mildew in Melon

    Science.gov (United States)

    Many physiological races of the cucurbit powdery mildew pathogen (CPM) Podosphaera xanthii (Castagne) Braun & Shishkoff have been reported on melon (Cucumis melo L.). Melon accession PI 313970 is the only reported source of host plant resistance to race S, which first appeared in Imperial Valley, CA...

  11. Characterization of Cucumber Mosaic Virus Originating from Cucurbits in Serbia

    Directory of Open Access Journals (Sweden)

    Ana Vučurović

    2011-01-01

    Full Text Available Cucumber mosaic virus (CMV is considered one of the most economically importantplant viruses and has a worldwide distribution and a very wide host range including plantsfrom family Cucurbitaceae. In Serbia, on cucurbits CMV was detected in single and mixedinfections with Zucchini yellow mosaic virus (ZYMV and Watermelon mosaic virus (WMV. Viruses,including CMV, are constantly present in cucurbit crops, but their frequency changesby year and locality. Surveys and sample collections were conducted in cucurbit crops inthe period from 2008 to 2009 at 15 localities in Vojvodina province, and sample testing wascarried out using the DAS-ELISA method and commercially available antisera for six economicallymost important cucurbit viruses. In 2008, a total of 51 samples were collected from13 cucurbit crops of oilseed pumpkin Olinka variety, squash, and bottle gourd and CMV wasdetected in a total of 55% of tested samples with symptoms of viral infection. The most commoninfectious type was mixed infection with ZYMV and WMV (35.3%, and then mixedinfection with ZYMV (17.7% and WMV (2%. A total of 599 symptomatic samples of oilseedpumpkin Olinka variety, zucchini squash varieties Beogradska and Tosca, squash, and wintersquash were collected in 15 cucurbits crops in 2009. CMV was present in 4.4% of totalcollected samples, in single infections in 1.3%, and in mixed with WMV or ZYMV in 1.3%, and1.8%. Five CMV isolates were obtained by mechanical inoculations of N. glutinosa and oneof them was selected for further biological characterization. Test plants which were describedto be hosts of CMV expressed symptoms characteristic for those caused by CMV afterinoculations by isolate 115-08. CMV specific primers Au1u/Au2d were used to amplify an850 bp fragment using RT-PCR method. Amplified fragment encodes the entire viral coatprotein (CP gene and partial 5’ and 3’ UTRs of two selected CMV isolates. Amplified fragmentswere sequenced and deposited in the NCBI, where

  12. Origin and evolution of cultivated cucurbits Origem e evolução de cucurbitáceas cultivadas

    Directory of Open Access Journals (Sweden)

    Dilson Antônio Bisognin

    2002-08-01

    Full Text Available Cucurbits (Cucurbitaceae are among the most important plant families supplying humans with edible products and useful fibers. Plants of this family are very similar in above ground development, but they have high genetic diversity for fruit shape and other fruit characteristics, resulting in a variety of uses. The objective of this review was to discuss the origin and evolution of the most important cultivated cucurbits. Understanding the evolutionary history and domestication process increase the possibility for better exploiting the genetic diversity for cultivar development. The domestication selection in cucurbits was for shape, less bitter flesh, larger and fewer seeds, and larger fruit size, resulting in high genetic diversity within and among cultivated species. This variation can be associated with the wide range of uses that require different shape, size and a constant ratio between fruit length and fruit diameter. The discussion of the breeding history indicates how artificial selection could speed up changes in fruit characteristics to attend specific uses and increase adaptation to a variety of environmental conditions in which cucurbits are growing worldwide. Although interspecific hybridization has been employed in cucurbit breeding more than in any other family, there is still a high potential for increasing its application for germplasm and cultivar development.As cucurbitáceas (Cucurbitaceae são uma das mais importantes famílias de plantas utilizadas para produção de alimentos e fibras. Apesar de a parte aérea das plantas desta família ser muito similar em seu desenvolvimento, grande variabilidade genética tem sido mantida para formato e outras características de fruto, o que aumenta o seu potencial de uso. O objetivo desta revisão foi discutir a origem e a evolução das cucurbitáceas cultivadas. A história da evolução e o conhecimento das alterações ocorridas durante este processo podem facilitar a utiliza

  13. Earthquake-like patterns of acoustic emission in crumpled plastic sheets

    Science.gov (United States)

    Mendes, R. S.; Malacarne, L. C.; Santos, R. P. B.; Ribeiro, H. V.; Picoli, S., Jr.

    2010-10-01

    We report remarkable similarities in the output signal of two distinct out-of-equilibrium physical systems —earthquakes and the intermittent acoustic noise emitted by crumpled plastic sheets, i.e. Biaxially Oriented Polypropylene (BOPP) films. We show that both signals share several statistical properties including the distribution of energy, distribution of energy increments for distinct time scales, distribution of return intervals and correlations in the magnitude and sign of energy increments. This analogy is consistent with the concept of universality in complex systems and could provide some insight on the mechanisms behind the complex behavior of earthquakes.

  14. The origin and composition of cucurbit "phloem" exudate.

    Science.gov (United States)

    Zhang, Cankui; Yu, Xiyan; Ayre, Brian G; Turgeon, Robert

    2012-04-01

    Cucurbits exude profusely when stems or petioles are cut. We conducted studies on pumpkin (Cucurbita maxima) and cucumber (Cucumis sativus) to determine the origin and composition of the exudate. Morphometric analysis indicated that the exudate is too voluminous to derive exclusively from the phloem. Cold, which inhibits phloem transport, did not interfere with exudation. However, ice water applied to the roots, which reduces root pressure, rapidly diminished exudation rate. Sap was seen by microscopic examination to flow primarily from the fascicular phloem in cucumber, and several other cucurbit species, but primarily from the extrafascicular phloem in pumpkin. Following exposure of leaves to 14CO2, radiolabeled stachyose and other sugars were detected in the exudate in proportions expected of authentic phloem sap. Most of this radiolabel was released during the first 20 s. Sugars in exudate were dilute. The sugar composition of exudate from extrafascicular phloem near the edge of the stem differed from that of other sources in that it was high in hexose and low in stachyose. We conclude that sap is released from cucurbit phloem upon wounding but contributes negligibly to total exudate volume. The sap is diluted by water from cut cells, the apoplast, and the xylem. Small amounts of dilute, mobile sap from sieve elements can be obtained, although there is evidence that it is contaminated by the contents of other cell types. The function of P-proteins may be to prevent water loss from the xylem as well as nutrient loss from the phloem.

  15. Cucurbit powdery mildews: Methodology for objective determination and denomination of races

    Science.gov (United States)

    Cucurbit powdery mildew (CPM), a disease on field and greenhouse cucurbit crops worldwide, is caused most frequently by two obligate erysiphaceous ectoparasites (Golovinomyces orontii s.l., Podosphaera xanthii) that are highly variable in their pathogenicity and virulence. Various, independent syste...

  16. Phylogenetic Relationships Among Cucurbit Species Used as Rootstocks for Grafting Watermelon

    Science.gov (United States)

    There is an increased interest in the United States in grafting watermelon on cucurbit rootstocks to control soilborne diseases. Several cucurbit species including Lagenaria siceraria, Cucurbita spp. and Benincasa hispida (wax gourds) have been used in Asia as rootstocks for watermelon. In our pre...

  17. Autonomous micromotor based on catalytically pneumatic behavior of balloon-like MnO(x)-graphene crumples.

    Science.gov (United States)

    Chen, Xueli; Wu, Guan; Lan, Tian; Chen, Wei

    2014-07-11

    A novel autonomous micromotor, based on catalytically pneumatic behaviour of balloon-like MnOx-graphene crumples, has been synthesized via an ultrasonic spray pyrolysis method. Through catalytic decomposition of H2O2 into O2, the gas accumulated in a confined space and was released to generate a strong force to push the micromotor.

  18. Cucurbit[8]uril/cucurbit[7]uril controlled off/on fluorescence of the acridizinium and 9-aminoacridizinium cations in aqueous solution.

    Science.gov (United States)

    Wang, Ruibing; Yuan, Lina; Ihmels, Heiko; Macartney, Donal H

    2007-01-01

    The blue fluorescence of acridizinium bromide (ADZ+) and the green fluorescence of 9-aminoacridizinium bromide (AADZ+) in aqueous solutions can be almost entirely switched off upon the double inclusion of these guests in the cavity of cucurbit[8]uril (CB[8]) owing to the formation of a nonfluorescent, noncovalent dimer complex, and then fluorescence can be effectively restored by adding cucurbit[7]uril (CB[7]) to the complex because it competitively extracts the fluorophores out of the CB[8] cavity.

  19. A novel fluorometric determination of melamine using cucurbit[7]uril

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Yunyou, E-mail: zy161299@mail.ahnu.edu.c [Anhui Key Laboratory of Functional Molecular Solids and Anhui Key Laboratory of Chemo-Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China); Yang Juan; Liu Min; Wang Sufan; Lu Qin [Anhui Key Laboratory of Functional Molecular Solids and Anhui Key Laboratory of Chemo-Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China)

    2010-05-15

    Melamine is a toxic compound to both animals and human beings, and is connected to various diseases, such as kidney stones and bladder cancer. For the efficient detection of melamine, we have developed a novel sensitive cucurbit[7]uril (CB7) sensor with a detection limit at 0.20 mug mL{sup -1}, and applied it to detect melamine in tainted milk. Fluorescence studies indicate that CB7 forms complex with melamine in a 1:1 mole ratio. The binding constant at various temperatures has been calculated and the interaction mechanism has been discussed based on molecular modeling result.

  20. Biology of Anastrepha grandis (Diptera: Tephritidae) in Different Cucurbits.

    Science.gov (United States)

    Bolzan, Anderson; Nava, Dori E; Garcia, Flávio R M; Valgas, Ricardo A; Smaniotto, Giovani

    2015-06-01

    Anastrepha grandis (Macquart) (Diptera: Tephritidae) is one of the main pests of cucurbits in Brazil. Losses occur due to the damage caused to the fruits and the embargo on exports, as A. grandis is considered a quarantine pest in countries that import Brazilian cucurbits. This study aimed to evaluate the development of A. grandis in hosts of the Cucurbitaceae family. The hosts used were stem squash (Cucurbita pepo L.), squash (Cucurbita moschata Duchesne), chayote [Sechium edule (Jacq.) Swartz], mini watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai], Spanish melon (Cucumis melo L.), hybrid squash "Tetsukabuto" (C. moschata×Cucurbita maxima Duchesne), and salad cucumber (Cucumis sativus L.). We evaluated the viability and duration of egg-to-pupa period, pupal weight, sex ratio, and average number of pupae per fruit under controlled conditions of temperature, relative humidity, and photophase. The preoviposition and oviposition periods, fecundity, fertility, and longevity of females were determined for adults. Hosts of the genus Cucurbita provided a better development of A. grandis in comparison with other hosts, and presented a greater number of insects on fruit as well as higher infestation rate. Fecundity and longevity were also higher for females that developed in hosts of the genus Cucurbita, although values of these biological parameters varied between stem squash, squash, hybrid squash "Tetsukabuto."

  1. Simultaneous multiplex PCR detection of seven cucurbit-infecting viruses.

    Science.gov (United States)

    Kwon, Ji Yeon; Hong, Jin Sung; Kim, Min Jea; Choi, Sun Hee; Min, Byeong Eun; Song, Eun Gyeong; Kim, Hyun Hee; Ryu, Ki Hyun

    2014-09-01

    Two multiplex polymerase chain reaction (PCR) systems using dual priming oligonucleotide (DPO) primers were developed for the simultaneous detection of seven cucurbit-infecting viruses. One system allows for the detection of papaya ringspot virus, watermelon mosaic virus, and zucchini yellow mosaic virus, whereas the other permits the detection of cucumber green mottle mosaic virus, cucumber fruit mottle mosaic virus, kyuri green mottle mosaic virus, and zucchini green mottle mosaic virus. Viral species-specific DPO primers developed in this study detected as little as 10 fg/μl of viral RNA under monoplex conditions and 10 pg/μl of viral RNA under multiplex conditions. Multiplex PCR using the DPO primer sets was capable of amplifying viral genes at annealing temperatures ranging from 53 °C to 63 °C. Whereas the use of conventional primers gave rise to non-specific bands, the DPO primers detected target viral genes in the absence of non-specific amplification. When these DPO multiplex primer sets were applied to virus-infected cucurbit samples obtained in the field, multiple infection as well as single infection was accurately identified. This novel approach could also detect multiple viruses in infected seeds. The reliability of multiplex PCR systems using DPO primers for plant virus detection is discussed.

  2. Virus symptoms and viruses associated with two cucurbit crops grown in a derived savannah agro-ecology in Nigeria

    Directory of Open Access Journals (Sweden)

    AYO-JOHN

    2014-06-01

    Full Text Available Five watermelon varieties, Sugar Baby, Charleston Grey, Kaolak, Crimson Sweet and Oranaise and three cucumber varieties, Poinsett, Ashley and Royal hybrid were grown on the field in two trials (i late season between August and October 2008 and (ii early season between April and June 2012 in Abeokuta, Ogun State to evaluate the cultivars for virus symptoms and viruses under natural tropical conditions. Symptomatic leaf samples were collected from each crop variety and indexed for Cucumber mosaic virus (CMV, Melon necrotic spot virus (MNSV, Papaya ringspot virus (PRSV, Watermelon mosaic virus (WMV, Zucchini yellow mosaic virus (ZYMV and Cucumber green mottle mosaic virus (CGMMV in Double Antibody Sandwich (DAS Enzyme-linked immunosorbent assay (ELISA. The disease incidence was 100.0% at 6 weeks after planting (WAP for all the cucurbits crops for both seasons while the highest symptom severity score at 10 WAP was 4 and 5 for watermelon and 3.6 and 4 for cucumber in the 1st and 2nd trials. The viruses detected in late season were CMV, CGMMV and MNSV which occurred in all the cucumber and watermelon varieties. In addition PRSV, WMV and ZYMV occurred in mixed infection in the cucumber varieties Pointsett and Royal Hybrid. In the early season, PRSV was the most prevalent virus infection in the cucumber and watermelon varieties. Also CMV+PRSV, PRSV+WMV, and MNSV+PRSV occurred in mixed infection in Charleston Grey, Oranaise and Sugar Baby respectively. The viruses detected are among the viruses reported to limit the production of cucurbit crops world-wide.

  3. Facile aerosol synthesis and characterization of ternary crumpled graphene-TiO₂-magnetite nanocomposites for advanced water treatment.

    Science.gov (United States)

    Jiang, Yi; Wang, Wei-Ning; Biswas, Pratim; Fortner, John D

    2014-07-23

    In this work, the synthesis and characterization of multifunctional crumpled graphene-based ternary nanocomposite photocatalysts for advanced water treatment applications is described. Currently, a major hurdle for the scale-up and optimization of aqueous, graphene-based photocatalysts is restacking of graphene nanosheets due to strong π-π interactions. To overcome this hurdle, a fast and facile aerosol technique to synthesize monomeric, aggregation-resistant, crumpled graphene-based photocatalysts was developed. The aerosol route utilizes water evaporation-induced confinement forces to effectively crumple graphene oxide and subsequently encapsulate commercially available TiO2 and magnetite nanoparticles. The as-synthesized crumpled graphene-TiO2-magnetite (GOTIM) ternary core-shell nanostructures are shown to possess superior aqueous-based photocatalytic properties (over a 20-fold enhancement in some cases) compared to TiO2 alone. Total GOTIM photocatalytic reactivity is confirmed to also include efficient photoreduction reaction pathways, in addition to expected oxidation routes typical of TiO2-based photocatalysts, significantly expanding photocatalytic application potential compared to TiO2 alone. Reaction kinetics and proposed mechanisms (both oxidative and reductive) are described for a model organic compound, here as methyl orange. Further, with the addition of hole scavengers such as EDTA, and/or lowering the O2 concentration, we demonstrate enhancement of photocatalyzed reduction reactions, suggesting potential for directed, controlled reduction applications. In addition to robust aqueous stability, low-field magnetic susceptibility is demonstrated, allowing for low-energy, in situ material separations, which are critical for material recycling and reuse.

  4. A general approach to one-pot fabrication of crumpled graphene-based nanohybrids for energy applications.

    Science.gov (United States)

    Mao, Shun; Wen, Zhenhai; Kim, Haejune; Lu, Ganhua; Hurley, Patrick; Chen, Junhong

    2012-08-28

    Crumpled graphene oxide (GO)/graphene is a new type of carbon nanostructure that has drawn growing attention due to its three-dimensional open structure and excellent stability in an aqueous solution. Here we report a general and one-step approach to produce crumpled graphene (CG)-nanocrystal hybrids, which are produced by direct aerosolization of a GO suspension mixed with precursor ions. Nanocrystals spontaneously grow from precursor ions and assemble on both external and internal surfaces of CG balls during the solvent evaporation and GO crumpling process. More importantly, CG-nanocrystal hybrids can be directly deposited onto various current-collecting substrates, enabling their tremendous potential for energy applications. As a proof of concept, we demonstrate the use of hybrid electrodes of CG-Mn(3)O(4) and CG-SnO(2) in an electrochemical supercapacitor and a lithium-ion battery, respectively. The performance of the resulting capacitor/battery is attractive and outperforms conventional flat graphene-based hybrid devices. This study provides a new and facile route to fabricating high-performance hybrid CG-nanocrystal electrodes for various energy systems.

  5. Yellowing disease in zucchini squash produced by mixed infections of Cucurbit yellow stunting disorder virus and Cucumber vein yellowing virus.

    Science.gov (United States)

    Gil-Salas, Francisco M; Peters, Jeff; Boonham, Neil; Cuadrado, Isabel M; Janssen, Dirk

    2011-11-01

    Zucchini squash is host to Cucurbit yellow stunting disorder virus (CYSDV), a member of the genus Crinivirus, and Cucumber vein yellowing virus (CVYV), a member of the genus Ipomovirus, both transmitted by the whitefly Bemisia tabaci. Field observations suggest the appearance of new symptoms observed on leaves of zucchini squash crops when both viruses were present. When infected during controlled experiments with CYSDV only, zucchini plants showed no obvious symptoms and the virus titer decreased between 15 and 45 days postinoculation (dpi), after which it was no longer detected. CVYV caused inconspicuous symptoms restricted to vein clearing on some of the apical leaves and the virus accumulated progressively between 15 and 60 dpi. Similar accumulations of virus followed single inoculations with the potyvirus Zucchini yellow mosaic virus (ZYMV) and plants showed severe stunting, leaf deformation, and mosaic yellowing. However, in mixed infections with CYSDV and CVYV, intermediate leaves showed chlorotic mottling which evolved later to rolling, brittleness, and complete yellowing of the leaf lamina, with exception of the veins. No consistent alteration of CVYV accumulation was detected but the amounts of CYSDV increased ≈100-fold and remained detectable at 60 dpi. Such synergistic effects on the titer of the crinivirus and symptom expression were not observed when co-infected with ZYMV.

  6. A study of the Fenton-mediated oxidation of methylene blue-cucurbit[n]uril complexes.

    Science.gov (United States)

    Fuenzalida, Tomás; Fuentealba, Denis

    2015-04-01

    Cucurbit[n]urils efficiently decreased the Fenton-mediated oxidation of encapsulated dyes, providing a mechanism for some control and selectivity over the degradation. The encapsulation of methylene blue into cucurbit[7]uril made it highly refractory against Fenton oxidation in the dark or under UVA light irradiation. However, the oxidation of the encapsulated dye was significantly enhanced under visible light irradiation. This behavior was selective for the cucurbit[7]uril complex and not for the cucurbit[8]uril complex, which achieved the same degree of protection irrespective of the irradiation conditions. This different reactivity of the complexes was further discussed in terms of their excited state properties. The main mechanism for protection was the seclusion of the dye into cucurbit[n]urils as shown by the fact that the non-encapsulated dye safranin was protected much less than methylene blue. Additionally, cucurbit[n]urils efficiently trapped hydroxyl radicals, which contributed significantly to the protection of the dyes from Fenton-mediated oxidation.

  7. Differential Life History Trait Associations of Aphids with Nonpersistent Viruses in Cucurbits.

    Science.gov (United States)

    Angelella, G M; Egel, D S; Holland, J D; Nemacheck, J A; Williams, C E; Kaplan, I

    2015-06-01

    The diversity of vectors and fleeting nature of virus acquisition and transmission renders nonpersistent viruses a challenge to manage. We assessed the importance of noncolonizing versus colonizing vectors with a 2-yr survey of aphids and nonpersistent viruses on commercial pumpkin farms. We quantified aphid alightment using pan traps, while testing leaf samples with multiplex RT-PCR targeting cucumber mosaic virus (CMV), zucchini yellow mosaic virus (ZYMV), watermelon mosaic virus (WMV), and papaya ringspot virus (PRSV). Overall, we identified 53 aphid species (3,899 individuals), from which the melon aphid, Aphis gossypii Glover, a pumpkin-colonizing species, predominated (76 and 37% of samples in 2010 and 2011, respectively). CMV and ZYMV were not detected, but WMV and PRSV were prevalent, both regionally (WMV: 28/29 fields, PRSV: 21/29 fields) and within fields (infection rates = 69 and 55% for WMV in 2010 and 2011; 28 and 25% for PRSV in 2010 and 2011). However, early-season samples showed extremely low infection levels, suggesting cucurbit viruses are not seed-transmitted and implicating aphid activity as a causal factor driving virus spread. Interestingly, neither noncolonizer and colonizer alightment nor total aphid alightment were good predictors of virus presence, but community analyses revealed species-specific relationships. For example, cowpea aphid (Aphis craccivora Koch) and spotted alfalfa aphid (Therioaphis trifolii Monell f. maculata) were associated with PRSV infection, whereas the oleander aphid (Aphis nerii Bover de Fonscolombe) was associated with WMV spread within fields. These outcomes highlight the need for tailored management plans targeting key vectors of nonpersistent viruses in agricultural systems.

  8. Crumpled Nitrogen-Doped Graphene for Supercapacitors with High Gravimetric and Volumetric Performances.

    Science.gov (United States)

    Wang, Jie; Ding, Bing; Xu, Yunling; Shen, Laifa; Dou, Hui; Zhang, Xiaogang

    2015-10-14

    Graphene is considered a promising electrochemical capacitors electrode material due to its high surface area and high electrical conductivity. However, restacking interactions between graphene nanosheets significantly decrease the ion-accessible surface area and impede electronic and ionic transfer. This would, in turn, severely hinder the realization of high energy density. Herein, we report a strategy for preparation of few-layer graphene material with abundant crumples and high-level nitrogen doping. The two-dimensional graphene nanosheets (CNG) feature high ion-available surface area, excellent electronic and ion transfer properties, and high packing density, permitting the CNG electrode to exhibit excellent electrochemical performance. In ionic liquid electrolyte, the CNG electrode exhibits gravimetric and volumetric capacitances of 128 F g(-1) and 98 F cm(-3), respectively, achieving gravimetric and volumetric energy densities of 56 Wh kg(-1) and 43 Wh L(-1). The preparation strategy described here provides a new approach for developing a graphene-based supercapacitor with high gravimetric and volumetric energy densities.

  9. Epidemiology of Cucurbit yellow stunting disorder virus in the US Southwest and development of virus resistant melon

    Science.gov (United States)

    Cucurbit yellow stunting disorder virus (CYSDV), emerged in the Southwest USA in 2006, where it is transmitted by the MEAM1 cryptic species of Bemisia tabaci. The virus results in late-season infection of spring melon crops with limited economic impact; however, all summer and fall cucurbits become ...

  10. Initiative for international cooperation of researchers and breeders related to determination and denomination of cucurbit powdery mildew races

    Science.gov (United States)

    Cucurbit powdery mildew (CPM) is caused most frequently by two obligate erysiphaceous ectoparasites, Golovinomyces orontii s.l. and Podosphaera xanthii, that are highly variable in virulence. Various independent systems of CPM race determination and denomination cause a chaotic situation in cucurbit...

  11. Potential Sources of Resistance to Cucurbit Powdery Mildew in US Plant Introductions (PI) of Lagenaria Siceraria (bottle gourd)

    Science.gov (United States)

    Powdery mildew (Podosphaera xanthii) can cause severe damage to cucurbit crops grown in open fields and greenhouses. In recent years, there has been a growing interest in the USA in grafting watermelon plants onto various cucurbit rootstocks. Bottle gourd plants (Lagenaria siceraria) are being use...

  12. Excellent catalytic effects of highly crumpled graphene nanosheets on hydrogenation/dehydrogenation of magnesium hydride

    Science.gov (United States)

    Liu, Guang; Wang, Yijing; Xu, Changchang; Qiu, Fangyuan; An, Cuihua; Li, Li; Jiao, Lifang; Yuan, Huatang

    2013-01-01

    Highly crumpled graphene nanosheets (GNS) with a BET surface area as high as 1159 m2 g-1 was fabricated by a thermal exfoliation method. A systematic investigation was performed on the hydrogen sorption properties of MgH2-5 wt% GNS nanocomposites acquired by ball-milling. It was found that the as-synthesized GNS exhibited a superior catalytic effect on hydrogenation/dehydrogenation of MgH2. Differential Scanning Calorimetry (DSC) and isothermal hydrogenation/dehydrogenation measurements indicated that both hydrogen sorption capacity and dehydrogenation/hydrogenation kinetics of the composites improved with increasing milling time. The composites MgH2-GNS milled for 20 h can absorb 6.6 wt% H2 within 1 min at 300 °C and 6.3 wt% within 40 min at 200 °C, even at 150 °C, it can also absorb 6.0 wt% H2 within 180 min. It was also demonstrated that MgH2-GNS-20 h could release 6.1 wt% H2 at 300 °C within 40 min. In addition, microstructure measurements based on XRD, SEM, TEM as well as Raman spectra revealed that the grain size of thus-prepared MgH2-GNS nanocomposites decreased with increasing milling time, moreover, the graphene layers were broken into smaller graphene nanosheets in a disordered and irregular manner during milling. It was confirmed that these smaller graphene nanosheets on the composite surface, providing more edge sites and hydrogen diffusion channels, prevented the nanograins from sintering and agglomerating, thus, leading to promotion of the hydrogenation/dehydrogenation kinetics of MgH2.Highly crumpled graphene nanosheets (GNS) with a BET surface area as high as 1159 m2 g-1 was fabricated by a thermal exfoliation method. A systematic investigation was performed on the hydrogen sorption properties of MgH2-5 wt% GNS nanocomposites acquired by ball-milling. It was found that the as-synthesized GNS exhibited a superior catalytic effect on hydrogenation/dehydrogenation of MgH2. Differential Scanning Calorimetry (DSC) and isothermal hydrogenation

  13. Stachyose synthesis in source leaf tissues of the CAM plant Xerosicyos danguyi H. Humb

    Energy Technology Data Exchange (ETDEWEB)

    Madore, M.A.; Mitchell, D.E.; Boyd, C.M. (Univ. of California, Riverside (USA))

    1988-07-01

    Leaf tissues from Xerosicyos danguyi H. Humb., a succulent member of the Cucurbitaceae, were found to possess both galactinol synthase activity and the capacity for photosynthetic production of stachyose, the phloem transport oligosaccahride common to other nonsucculent cucurbits, the amounts of stachyose isolated from leaf tissues, and the extractable activity of galactinol synthase, were somewhat higher in leaf tissues obtained from plants operating in the Crassulacean acid metabolism (CAM) mode (well watered plants) compared to leaf tissues from plants operating in the CAM-idling mode (water-stressed plants). In contrast, in leaf discs, the photosynthetic incorporation of label into stachyose following pulse labeling with {sup 14}CO{sub 2} was similar for stressed and for nonstressed tissues. Stachyose could be extracted from, and was synthesized photosynthetically by, leaf discs which contained no vascular tissues, indicating that synthesis of stachyose can occur in photosynthetic mesophyll cells of Xerosicyos.

  14. Cucurbit[6]uril-Promoted Click Chemistry for Protein Modification.

    Science.gov (United States)

    Finbloom, Joel A; Han, Kenneth; Slack, Clancy C; Furst, Ariel L; Francis, Matthew B

    2017-07-19

    Azide-alkyne cycloaddition is a powerful reaction for the formation of bioconjugates. When catalyzed by Cu(I) or strain promotion, this cycloaddition is considered to be a "click" reaction with many applications in chemical biology and materials science. We report a new type of azide-alkyne click chemistry for the synthesis of protein conjugates using cucurbit[6]uril (CB6) supramolecular chemistry. CB6-promoted azide-alkyne cycloaddition has been previously used for the synthesis of rotaxanes but has not been applied to the development of complex bioconjugates. By developing new substrates for CB6 click that do not contain any cross-reactive functional groups and by optimizing reaction conditions, we converted CB6 click chemistry from a rotaxane synthesis tool into a useful bioconjugation technique. Using these new parameters, we synthesized a series of protein conjugates including protein-peptide, protein-DNA, protein-polymer, and protein-drug conjugates. We further demonstrated that CB6 click can be used in conjunction with strain-promoted azide-alkyne cycloaddition to generate distinct bioconjugates in protein mixtures. CB6 click is a promising new reaction for the development of protein conjugates and can be applied toward the synthesis of complex biomaterials for a wide range of applications.

  15. Synthesis and Crystal Structure of a Binuclear Gadolinium(Ⅲ) Complex Bridged by Cucurbit[6]uril

    Institute of Scientific and Technical Information of China (English)

    Gui Ling ZHANG; Zhi Yong WU; Yan Tuan LI; Da Qi WANG; Jian Min DOU

    2006-01-01

    A new cucurbit[6]uril bridged binuclear complex {[Gd(H2O)6]2[Q6(H2O)]}Cl6·4H2O,where Q6 represents cucurbit[6]uril, has been synthesized and characterized by X-ray diffraction.The crystal structure shows that the complex has an extended cucurbit[6]uril-bridged structure consisting of two gadolinium(Ⅲ) ions, in which each gadolinium(Ⅲ) ion is coordinated with two neighboring carbonylic oxygen atoms of Q6 and six oxygen atoms of water molecules that leans toward one side of the portal. One disordered guest water molecule resides in the Q6 molecule cavity and occupies two different positions. Hydrogen bonds assemble the complex to three-dimensional supramolecular structure.

  16. Phylogenetic analysis of Melon chlorotic leaf curl virus from Guatemala: Another emergent species in the Squash leaf curl virus clade

    KAUST Repository

    Brown, J.K.

    2011-06-01

    The genome of a new bipartite begomovirus Melon chlorotic leaf curl virus from Guatemala (MCLCuV-GT) was cloned and the genome sequence was determined. The virus causes distinct symptoms on melons that were not previously observed in melon crops in Guatemala or elsewhere. Phylogenetic analysis of MCLCuV-GT and begomoviruses infecting cucurbits and other host plant species indicated that its closest relative was MCLCuV from Costa Rica (MCLCuV-CR). The DNA-A components of two isolates shared 88.8% nucleotide identity, making them strains of the same species. Further, both MCLCuV-GT and MCLCuV-CR grouped with other Western Hemisphere cucurbit-infecting species in the SLCV-clade making them the most southerly cucurbit-infecting members of the clade to date. Although the common region of the cognate components of MCLCuV-GT and MCLCuV-CR, shared similar to 96.3% nucleotide identity. While DNA-A and DNA-B components of MCLCuV-GT were less than 86% nucleotide identity with the respective DNAA and DNA-B common regions of MCLCuV-CR. The late viral genes of the two strains shared the least nt identity (<88%) while their early genes shared the highest nt identity (>90%). The collective evidence suggests that these two strains of MCLCuV are evolutionarily divergent owing in part to recombination, but also due to the accumulation of a substantial number of mutations. In addition they are differentially host-adapted, as has been documented for other cucurbit-infecting, bean-adapted, species in the SLCV clade. (C) 2011 Elsevier B.V. All rights reserved.

  17. Evidence for cucurbit powdery mildew pathogen races based on watermelon differentials

    Science.gov (United States)

    Powdery mildew (PM) caused by Podosphaera xanthii occurs in open fields and greenhouses and can severely limit cucurbit production. Presently seven races of P. xanthii have been identified using melon (Cucumis melo) differentials. Physiological races of this pathogen have not been classified for ot...

  18. Podosphaera xanthii but not Golovinomyces cichoracearum infects Cucurbits in a Greenhouse at Salinas, California

    Science.gov (United States)

    Two fungal species are the primary causes of cucurbit powdery mildew (CPM): Podosphaera xanthii and Golovinomyces cichoracearum. CPM on melon (Cucumis melo L.), cucumber (C. sativus L.) and summer squash (Cucurbita pepo L.) in a greenhouse at Salinas, California in winter 2011 was confirmed to be in...

  19. Cucurbit powdery mildew of melon incited by Podosphaera xanthii: global and western U.S. perspectives

    Science.gov (United States)

    Cucurbit powdery mildew (CPM) is a major problem of melon (Cucumis melo L.) production worldwide, that is mostly caused by two fungi: Podosphaera xanthii and Golovinomyces cichoracearum (DC) V.P. Heluta (formerly Erysiphe cichoracearum). The two species may co-infect in some areas of northern Europe...

  20. Recessive resistance to Cucurbit yellow stunting disorder virus in melon TGR 1551

    Science.gov (United States)

    Cucurbit yellow stunting disorder virus (CYSDV) reduces melon (Cucumis melo L.) fruit quality and yield in many parts of the world. Host plant resistance of melon to CYSDV is a high priority for sustainable melon production in affected production areas. High-level resistance to CYSDV exhibited by TG...

  1. First report of zucchini tigre mosaic virus infecting several cucurbit plants in China

    Science.gov (United States)

    Pumpkin (Cucurbita moschata Duch.), Cucumber (Cucumis sativus Linn.) and Zucchini (Cucurbita pepo Linn.) are important crops in tropical and subtropical regions in the world, and they are popular vegetable crops in China. There are currently 59 viruses known infecting cucurbit plants which including...

  2. Supramolecular Controlled Cargo Release via Near Infrared Tunable Cucurbit[7]uril-Gold Nanostars.

    Science.gov (United States)

    Han, Yanwei; Yang, Xiran; Liu, Yingzhu; Ai, Qiushuang; Liu, Simin; Sun, Chunyan; Liang, Feng

    2016-02-26

    The near infrared (NIR) absorption and average particle size of gold nanostars (GNSs) can be precisely controlled by varying the molar ratios of cucurbit[7]urils (CB[7]) and GNSs in aqueous solution. GNSs modified with CB[7] achieved high cargo loading with thermally activated release upon the NIR laser irradiation.

  3. Powdery mildew resistant cucurbit rootstocks confer tolerance to grafted susceptible watermelon scions

    Science.gov (United States)

    Cucurbit powdery mildew (PM) caused by Podosphaera xanthii can impact seedling growth and cause serious losses in greenhouse and open fields. We have developed watermelon and bottle gourd germplasm lines with high levels of resistance to PM. A PM susceptible watermelon cultivar Mickey Lee (ML) was g...

  4. Size-tunable supramolecular nanoparticles mediated by ternary cucurbit (8)uril host-guest interactions

    NARCIS (Netherlands)

    Stoffelen, C.; Huskens, Jurriaan

    2013-01-01

    The formation of size-tunable, supramolecular nanoparticles (SNPs), employing cucurbit[8]uril-assisted naphthol–viologen charge-transfer complexes, is strongly time and temperature dependent. Yet, the ternary complex formation is fast at all temperatures employed. This indicates that SNP formation

  5. The cucurbits of mediterranean antiquity: identification of taxa from ancient images and descriptions.

    Science.gov (United States)

    Janick, Jules; Paris, Harry S; Parrish, David C

    2007-12-01

    A critical analysis was made of cucurbit descriptions in Dioscorides' De Materia Medica, Columella's De Re Rustica and Pliny's Historia Naturalis, works on medicine, agriculture and natural science of the 1st century ce, as well as the Mishna and Tosefta, compilations of rabbinic law derived from the same time period together with cucurbit images dating from antiquity including paintings, mosaics and sculpture. The goal was to identify taxonomically the Mediterranean cucurbits at the time of the Roman Empire. By ancient times, long-fruited forms of Cucumis melo (melon) and Lagenaria siceraria (bottle gourd) were selected, cultivated and used as vegetables around the Mediterranean and, in addition, bottle-shaped fruits of L. siceraria were employed as vessels. Citrullus lanatus (watermelons) and round-fruited forms of Cucumis melo (melons) were also consumed, but less commonly. A number of cucurbit species, including Bryonia alba, B. dioica, Citrullus colocynthis and Ecballium elaterium, were employed for medicinal purposes. No unequivocal evidence was found to suggest the presence of Cucumis sativus (cucumber) in the Mediterranean area during this era. The cucumis of Columella and Pliny was not cucumber, as commonly translated, but Cucumis melo subsp. melo Flexuosus Group (snake melon or vegetable melon).

  6. Tolerance to Cucurbit Powdery Mildew in USDA Bottle Gourd (Lagenaria siceraria) Plant Introductions (PI)

    Science.gov (United States)

    Powdery mildew (Podosphaera xanthii) can cause severe damage to cucurbit crops grown in open fields and greenhouses. Bottle gourd plants (Lagenaria siceraria) are being used throughout the world as rootstocks for grafting watermelon. In recent years, there has been a growing interest in the USA in...

  7. Cucurbit[6]uril: A Possible Host for Noble Gas Atoms.

    Science.gov (United States)

    Pan, Sudip; Mandal, Subhajit; Chattaraj, Pratim K

    2015-08-27

    Density functional and ab initio molecular dynamics studies are carried out to investigate the stability of noble gas encapsulated cucurbit[6]uril (CB[6]) systems. Interaction energy, dissociation energy and dissociation enthalpy are calculated to understand the efficacy of CB[6] in encapsulating noble gas atoms. CB[6] could encapsulate up to three Ne atoms having dissociation energy (zero-point energy corrected) in the range of 3.4-4.1 kcal/mol, whereas due to larger size, only one Ar or Kr atom encapsulated analogues would be viable. The dissociation energy value for the second Ar atom is only 1.0 kcal/mol. On the other hand, the same for the second Kr is -0.5 kcal/mol, implying the instability of the system. The noble gas dissociation processes are endothermic in nature, which increases gradually along Ne to Kr. Kr encapsulated analogue is found to be viable at room temperature. However, low temperature is needed for Ne and Ar encapsulated analogues. The temperature-pressure phase diagram highlights the region in which association and dissociation processes of Kr@CB[6] would be favorable. At ambient temperature and pressure, CB[6] may be used as an effective noble gas carrier. Wiberg bond indices, noncovalent interaction indices, electron density, and energy decomposition analyses are used to explore the nature of interaction between noble gas atoms and CB[6]. Dispersion interaction is found to be the most important term in the attraction energy. Ne and Ar atoms in one Ng entrapped analogue are found to stay inside the cavity of CB[6] throughout the simulation at 298 K. However, during simulation Ng2 units in Ng2@CB[6] flip toward the open faces of CB[6]. After 1 ps, one Ne atom of Ne3@CB[6] almost reaches the open face keeping other two Ne atoms inside. At lower temperature (77 K), all the Ng atoms in Ngn@CB[6] remain well inside the cavity of CB[6] throughout the simulation time (1 ps).

  8. A Novel Strain of Tomato Leaf Curl New Delhi Virus Has Spread to the Mediterranean Basin

    Directory of Open Access Journals (Sweden)

    Isabel M. Fortes

    2016-11-01

    Full Text Available Tomato leaf curl New Delhi virus (ToLCNDV is a whitefly-transmitted bipartite begomovirus (genus Begomovirus, family Geminiviridae that causes damage to multiple cultivated plant species mainly belonging to the Solanaceae and Cucurbitaceae families. ToLCNDV was limited to Asian countries until 2012, when it was first reported in Spain, causing severe epidemics in cucurbit crops. Here, we show that a genetically-uniform ToLCNDV population is present in Spain, compatible with a recent introduction. Analyses of ToLCNDV isolates reported from other parts of the world indicated that this virus has a highly heterogeneous population genetically with no evident geographical, plant host or year-based phylogenetic groups observed. Isolates emerging in Spain belong to a strain that seems to have evolved by recombination. Isolates of this strain seem adapted to infecting cucurbits, but poorly infect tomatoes.

  9. Detection of Papaya ringspot virus type W infecting the cucurbit weed Cucumis melo var. dudaim in Florida

    Science.gov (United States)

    This is the first report of Papaya ringspot virus type W infecting Cucumis melo var. dudaim, a cucurbit weed, in Florida. It provides an overview of this virus reservoir for growers, extension workers, crop consultants and research and regulatory scientists....

  10. Synthesis and Crystal Structure of Macrocyclic Cavitand Cucurbit[5]uril and Its Supramolecular Adduct with Cu(Ⅱ)

    Institute of Scientific and Technical Information of China (English)

    LIU,Si-Min(刘思敏); HUANG,Zi-Xiang(黄子祥); WU,Xiao-Jun(吴晓军); LIANG,Feng(梁峰); WU,Cheng-Tai(吴成泰)

    2004-01-01

    The first supramolecular adduct (H3O)2[Cu(H2O)4](SO4)2·2(C30H30N20O10)·24(H2O) based on cucurbit[5]uril was synthesized and characterized by single crystal X-ray diffraction analysis. In the adduct, copper ion is coordinated by four oxygen atoms from H2O. The latter links two cucurbit[5]uril molecules due to a complicated hydrogen bonding containing lattice water molecules.

  11. The Effect of Different Cucurbit Rootstocks on Some Morphological and Physiological Traits of Cucumber (Cucumis sativus cv. Super Dominus

    Directory of Open Access Journals (Sweden)

    reihane Mesgari

    2017-02-01

    Full Text Available Introduction: Cucumber is one of the most important vegetable crops for the local consumption and exportation. The use of grafted vegetable seedlings has been popular in many countries during recent years. Growing fruit-bearing vegetables, chiefly tomato, cucumber and watermelon through grafted seedlings become a widespread practice worldwide. Grafting is a valuable technique to avoid soil-borne diseases, provide biotic and abiotic stress tolerance, enhance nutrient uptake, optimize water use, and increase fruit yield and quality. Vegetable grafting is a new topic in Iran and there are a limited number of studies on grafted vegetable production. However, attention to grafting by researchers has recently increased. Suitable rootstocks should be identified and characterized for the effective utilization of grafting. The rootstock's vigorous root system increases the efficiency of water and nutrient absorption, and may also serve as a source of endogenous plant hormones, thus leading to increased growth and yield in addition to disease control. In the present study, we investigated the response of two Cucurbita sp. and an Iranian melon as rootstocks for cucumber. Materials and methods: In order to study the effect of cucurbit rootstocks and grafting method on growth, yield and fruit quality of cucumber (Cucumis sativus cv. Super Dominus, an experiment was conducted as a factorial design in the base of RCBD with three replications in the greenhouse and research farm, University of Zanjan. Treatments were included three rootstocks (Cucurbita moschata L., Lagenaria siceraria and Cucumis melo L. and ungrafted plants (control and two grafting method (hole insertion and splice grafting. Seeds were sown simultaneously in plastic pots. For obtaining the same stem diameter of scion and rootstocks, cucumber seeds were planted four days earlier than rootstocks seeds. The seedlings were grown in an environment-controlled greenhouse with 25/20 day

  12. Biological and Molecular Characterization of a Korean Isolate of Cucurbit aphid-borne yellows virus Infecting Cucumis Species in Korea.

    Science.gov (United States)

    Choi, Seung-Kook; Yoon, Ju-Yeon; Choi, Gug-Seoun

    2015-12-01

    Surveys of yellowing viruses in plastic tunnels and in open field crops of melon (Cucumis melo cultivar catalupo), oriental melon (C. melo cultivar oriental melon), and cucumber (C. sativus) were carried out in two melon-growing areas in 2014, Korea. Severe yellowing symptoms on older leaves of melon and chlorotic spots on younger leaves of melon were observed in the plastic tunnels. The symptoms were widespread and included initial chlorotic lesions followed by yellowing of whole leaves and thickening of older leaves. RT-PCR analysis using total RNA extracted from diseased leaves did not show any synthesized products for four cucurbit-infecting viruses; Beet pseudo-yellows virus, Cucumber mosaic virus, Cucurbit yellows stunting disorder virus, and Melon necrotic spot virus. Virus identification using RT-PCR showed Cucurbit aphid-borne yellows Virus (CABYV) was largely distributed in melon, oriental melon and cucumber. This result was verified by aphid (Aphis gossypii) transmission of CABYV. The complete coat protein (CP) gene amplified from melon was cloned and sequenced. The CP gene nucleotide and the deduced amino acid sequence comparisons as well as phylogenetic tree analysis of CABYV CPs showed that the CABYV isolates were undivided into subgroups. Although the low incidence of CABYV in infections to cucurbit crops in this survey, CABYV may become an important treat for cucurbit crops in many different regions in Korea, suggesting that CABYV should be taken into account in disease control of cucurbit crops in Korea.

  13. Biological and Molecular Characterization of a Korean Isolate of Cucurbit aphid-borne yellows virus Infecting Cucumis Species in Korea

    Directory of Open Access Journals (Sweden)

    Seung-Kook Choi

    2015-12-01

    Full Text Available Surveys of yellowing viruses in plastic tunnels and in open field crops of melon (Cucumis melo cultivar catalupo, oriental melon (C. melo cultivar oriental melon, and cucumber (C. sativus were carried out in two melon-growing areas in 2014, Korea. Severe yellowing symptoms on older leaves of melon and chlorotic spots on younger leaves of melon were observed in the plastic tunnels. The symptoms were widespread and included initial chlorotic lesions followed by yellowing of whole leaves and thickening of older leaves. RT-PCR analysis using total RNA extracted from diseased leaves did not show any synthesized products for four cucurbit-infecting viruses; Beet pseudo-yellows virus, Cucumber mosaic virus, Cucurbit yellows stunting disorder virus, and Melon necrotic spot virus. Virus identification using RT-PCR showed Cucurbit aphid-borne yellows Virus (CABYV was largely distributed in melon, oriental melon and cucumber. This result was verified by aphid (Aphis gossypii transmission of CABYV. The complete coat protein (CP gene amplified from melon was cloned and sequenced. The CP gene nucleotide and the deduced amino acid sequence comparisons as well as phylogenetic tree analysis of CABYV CPs showed that the CABYV isolates were undivided into subgroups. Although the low incidence of CABYV in infections to cucurbit crops in this survey, CABYV may become an important treat for cucurbit crops in many different regions in Korea, suggesting that CABYV should be taken into account in disease control of cucurbit crops in Korea.

  14. Cucurbit[7]uril disrupts aggregate formation between rhodamine B dyes covalently attached to glass substrates.

    Science.gov (United States)

    Halterman, Ronald L; Moore, Jason L; Yip, Wai Tak

    2011-07-01

    Dye aggregation is detrimental to the performance of high optical density dye-doped photonic materials. To overcome this challenge, the ability of cucurbit[7]uril (CB7) as a molecular host to disrupt aggregate formation on glass substrates was examined. Rhodamine B was covalently attached to glass slides by initially coating the surface with azidohexylsiloxane followed by copper-catalyzed "click" triazole formation with rhodamine B propargyl ester. The absorption and emission spectra of rhodamine B coated slides in water indicated diverse heterogeneous properties as surface dye density varied. Fluorescence quenching due to dye aggregation was evident at high surface dye density. Addition of aqueous cucurbit[7]uril (CB7) to the surface-tethered dyes perturbed the spectra to reveal a considerable reduction in heterogeneity, which suggested that the presence of a surface in close proximity does not significantly impair CB7's ability to complex with tethered rhodamine B.

  15. Triple emission from p-dimethylaminobenzonitrile-cucurbit[8]uril triggers the elusive excimer emission.

    Science.gov (United States)

    Sayed, Mhejabeen; Biedermann, Frank; Uzunova, Vanya D; Assaf, Khaleel I; Bhasikuttan, Achikanath C; Pal, Haridas; Nau, Werner M; Mohanty, Jyotirmayee

    2015-01-01

    The intriguing dual-emission behavior of p- dimethylaminobenzonitrile (DMABN) and the identity of the associated excited states is, arguably, the most extensively investigated and also controversially discussed molecule- specific phenomenon of modern photochemistry. We have now found a new, third fluorescence band when DMABN is encapsulated within the water-soluble molecular container cucurbit[8]uril (CB8). It is centered between the previously observed emissions and assigned to the elusive excimer emission from DMABN through 1:2 CB8:DMABN complex formation. Heating of the CB8⋅(DMABN)2 complex from 0 to 100 °C results in the dissociation of the ternary complex and restoration of the dual-emission properties of the monomer. Alternatively, monomer emission can be obtained by selecting cucurbit[7]uril (CB7), a host homologue that is too small to accommodate two DMABN molecules, or by introducing ethyl instead of methyl groups at the amino terminus of the aminobenzonitrile guest.

  16. Cucurbit[7]uril as a tool in the green synthesis of gold nanoparticles.

    Science.gov (United States)

    Premkumar, Thathan; Geckeler, Kurt E

    2010-12-03

    A simple, green, one-pot synthesis of gold nanoparticles was achieved through the reaction of an aqueous mixture of potassium tetrachloroaurate(III) and the macrocycle cucurbit[7]uril in the presence of sodium hydroxide at room temperature without introducing any kind of traditional reducing agents and/or external energy. The as-prepared gold nanoparticles showed catalytic activity for the reduction reaction of 4-nitrophenol in the presence of NaBH(4), which has been established by visual inspection and UV/Vis spectroscopy. This report is the first for the preparation of gold nanoparticles using cucurbit[7]uril in aqueous media through chemical reduction without employing conventional reducing agents and/or external energy.

  17. CHARACTERIZATION OF CUCURBIT PRODUCTION SYSTEMS AND DISEASE PREVALENCE IN MUNICIPALITIES IN PERNAMBUCO

    Directory of Open Access Journals (Sweden)

    GERFFESON THIAGO MOTA DE ALMEIDA SILVA

    2016-01-01

    Full Text Available Cucurbits have great economic, nutritional and social importance in the Brazilian semiarid region. In this region, many factors can result in reduced productivity of these crops, especially fungal and viral diseases. Therefore, knowledge of cucurbits is crucial for proper disease management. The objective of this work was to identify the major diseases of cucurbits grown in some municipalities in the Hinterland of the state of Pernambuco. Thus, plant samples were collected with symptoms in crops in the municipalities of Salgueiro, Serra Talhada, Floresta, Petrolândia, Ibimirim, Custódia and Inajá. A questionnaire was also applied to gather information about the production profile of producers. Seven fungal pathogens infecting cucurbits were identified: Pseudoperonospora cubensis, Colletotrichum sp., Podosphaera xanthii, Rhizoctonia solani, Didymella bryoniae, Fusarium sp. e Alternaria sp., and three viruses as well: Papaya ringspot virus - watermelon strain (PRSV-W, Watermelon mosaic virus (WMV, Zucchini yellow mosaic virus (ZYMV. It was found that in small crops, there is limited search for technical information om cropping, and these crops originate mostly from native seeds, in contrast to medium and large producers, who use improved cultivars. The melon and watermelon crops are the most commercially exploited, while pumpkins are used in subsistence agriculture. As for plant health problems, most respondents reported knowing the main diseases that occur in crops and perform disease control based on personal experience and / or through the help of the technical assistance provided by agricultural stores. In a few cases, in large farms, there was an agronomist to assist in this type of control.

  18. Binding Studies of Cucurbit[7]uril with Gold Nanoparticles Bearing Different Surface Functionalities‡

    OpenAIRE

    Tonga, Gulen Yesilbag; Mizuhara, Tsukasa; Saha, Krishnendu; Jiang, Ziwen; Hou, Singyuk; Das, Riddha; Rotello, Vincent M.

    2015-01-01

    Host-guest interactions between a synthetic receptor, cucurbit[7]uril (CB[7]), and gold nanoparticles (AuNPs) have been quantified using isothermal titration calorimetry. AuNPs were functionalized with ligands containing tertiary or quaternary benzylamine derivatives, with electron donating or withdrawing groups at the para position of the benzene ring. Analysis of binding interactions reveals that functional groups at the para position have no significant effect on binding constant. However,...

  19. Determination of nevirapine in the presence of cucurbit(7uril with a gold electrode

    Directory of Open Access Journals (Sweden)

    ELÍAS BLANCO

    2014-02-01

    Full Text Available The electrochemical oxidation of nevirapine, an anti-HIV drug, at a gold electrode was studied by voltammetric techniques. Nevirapine showed a signal that interfered with a working electrode wave. This interference was solved by the use of cucurbit(7uril allowing nevirapine to be determined in tablets (80.4 % recovery, presence of stavudine and lamivudine and urine (98.4 %.

  20. Cucurbits depicted in Byzantine mosaics from Israel, 350–600 ce

    Science.gov (United States)

    Avital, Anat; Paris, Harry S.

    2014-01-01

    Background and Aims Thousands of floor mosaics were produced in lands across the Roman and Byzantine empires. Some mosaics contain depictions of agricultural produce, potentially providing useful information concerning the contemporary presence and popularity of crop plants in a particular geographical region. Hundreds of floor mosaics produced in Israel during the Byzantine period have survived. The objective of the present work was to search these mosaics for Cucurbitaceae in order to obtain a more complete picture of cucurbit crop history in the eastern Mediterranean region. Results and Conclusions Twenty-three mosaics dating from 350–600 ce were found that had images positively identifiable as cucurbits. The morphological diversity of the cucurbit fruits in the mosaics of Israel is greater than that appearing in mosaics from any other Roman or Byzantine provincial area. The depicted fruits vary in shape from oblate to extremely long, and some are furrowed, others are striped and others lack definite markings. The cucurbit taxa depicted in the mosaics are Cucumis melo (melon), Citrullus lanatus (watermelon), Luffa aegyptiaca (sponge gourd) and Lagenaria siceraria (bottle gourd). Cucumis melo is the most frequently found taxon in the mosaics and is represented by round dessert melons and long snake melons. Fruits of at least two cultivars of snake melons and of watermelons are represented. To our knowledge, images of sponge gourds have not been found in Roman and Byzantine mosaics elsewhere. Indeed, the mosaics of Israel contain what are probably the oldest depictions of Luffa aegyptiaca in Mediterranean lands. Sponge gourds are depicted often, in 11 of the mosaics at eight localities, and the images include both mature fruits, which are useful for cleaning and washing, and immature fruits, which are edible. Only one mosaic has images positively identifiable as of bottle gourds, and these were round–pyriform and probably used as vessels. PMID:24948671

  1. Population dynamics, distribution, and species diversity of fruit flies on cucurbits in Kashmir Valley, India.

    Science.gov (United States)

    Ganie, S A; Khan, Z H; Ahangar, R A; Bhat, H A; Hussain, Barkat

    2013-01-01

    Given the economic importance of cucurbits and the losses incurred by fruit fly infestation, the population dynamics of fruit flies in cucurbit crops and the influence of abiotic parameters, such as temperature, relative humidity, rainfall, and total sunshine hours per day on the fruit fly population were studied. The study was carried out at six locations; in district Srinagar the locations were Batmaloo, Shalimar, and Dal, while in district Budgam the locations were Chadoora, Narkara, and Bugam (Jammu and Kashmir, India). Various cucurbit crops, such as cucumber, bottle gourd, ridge gourd and bitter gourd, were selected for the study. With regard to locations, mean fruit fly population was highest (6.09, 4.55, 3.87, and 3.60 flies/trap/week) at Batamaloo and Chadoora (4.73, 3.93, 2.73, and 2.73 flies/trap/week) on cucumber, bottle gourd, ridge gourd, and bitter gourd, respectively. The population of fruit flies was significantly correlated with the minimum and maximum temperature. The maximum species diversity of fruit flies was 0.511, recorded in Chadoora. Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae) was the most predominant species in both Srinagar and Budgam, followed by B. dorsalis (Hendel) and B. tau (Walker), while B. scutellaris (Bezzi) was found only in Chadoora. Results of the present investigation may be utilized in developing a sustainable pest management strategy in the agroecological system.

  2. Application of Multiplex RT-PCR for Detection of Cucurbit-infecting Tobamovirus

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    Budi Setiadi Daryono

    2015-11-01

    Full Text Available Cucumber green mottle mosaic virus (CGMMV and Kyuri green mottle mosaic virus (KGMMV are seed borne viruses and they are also transmitted mechanically during agricultural practice and through water. Hence, these viruses have potential diseases widely distributed throughout the world. To detect different strains of CGMMV and KGMMV, several specific primers for each virus were designed for single and multiplex RT-PCR. The results of single and multiplex RT-PCR showed that CGMMV was detected in zucchini isolated in Bali-Indonesia, while KGMMV was detected both in zucchini isolated in Bali-Indonesia and Cucumis metuliferus isolated in Thailand. Furthermore, artificial co-infection of these two viruses was prepared and carried out using two different ways of viral RNAs extraction. Based on the results, it could be reported that viral RNAs for cDNA amplification by multiplex RT-PCR could be extracted from a mixture of infected leaves or separate extraction of each viruses infected leaves. In addition, results presented in this study demonstrated the application of multiplex RT-PCR to simultaneously detect CGMMV and KGMMV from cucurbit leaves using a mixture of four primers and its feasibility as a sensitive and rapid laboratory assay. Since, no multiplex RT-PCR technique has been described for the detection of CGMMV and KGMMV, this technique can be a good option for sensitive and reliable tool for detection of two major cucurbit infecting Tobamoviruses.Keywords : Cucurbit infecting Tobamovirus, multiplex RT-PCR, seed borne viruses

  3. The Origin and Composition of Cucurbit “Phloem” Exudate1[OA

    Science.gov (United States)

    Zhang, Cankui; Yu, Xiyan; Ayre, Brian G.; Turgeon, Robert

    2012-01-01

    Cucurbits exude profusely when stems or petioles are cut. We conducted studies on pumpkin (Cucurbita maxima) and cucumber (Cucumis sativus) to determine the origin and composition of the exudate. Morphometric analysis indicated that the exudate is too voluminous to derive exclusively from the phloem. Cold, which inhibits phloem transport, did not interfere with exudation. However, ice water applied to the roots, which reduces root pressure, rapidly diminished exudation rate. Sap was seen by microscopic examination to flow primarily from the fascicular phloem in cucumber, and several other cucurbit species, but primarily from the extrafascicular phloem in pumpkin. Following exposure of leaves to 14CO2, radiolabeled stachyose and other sugars were detected in the exudate in proportions expected of authentic phloem sap. Most of this radiolabel was released during the first 20 s. Sugars in exudate were dilute. The sugar composition of exudate from extrafascicular phloem near the edge of the stem differed from that of other sources in that it was high in hexose and low in stachyose. We conclude that sap is released from cucurbit phloem upon wounding but contributes negligibly to total exudate volume. The sap is diluted by water from cut cells, the apoplast, and the xylem. Small amounts of dilute, mobile sap from sieve elements can be obtained, although there is evidence that it is contaminated by the contents of other cell types. The function of P-proteins may be to prevent water loss from the xylem as well as nutrient loss from the phloem. PMID:22331409

  4. Detection, differentiation and phylogenetic analysis of cucumber mosaic virus isolates from cucurbits in the northwest region of Iran.

    Science.gov (United States)

    Bashir, Nemat Sokhandan; Kalhor, Mohammad Rasaei; Zarghani, Shaheen Nourinejhad

    2006-06-01

    One hundred and twenty three cucurbit samples with one or more symptoms of leaf mosaic, leaf distortion, fruit mosaic, stunting, mottling and yellowing were collected from several locations in the northwest region of Iran. Screening by double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) with a cucumber mosaic virus (CMV) polyclonal antibody, produced positive reactions from 13 samples. However, none of these positive samples reacted with a CMV subgroup-II (S-II)-specific monoclonal antibody in a triple antibody sandwich (TAS)-ELSIA. When total RNA from the CMV-infected samples was subjected to reverse transcription polymerase chain reaction (RT-PCR) with a pair of primers corresponding to the flanking regions of the virus coat protein (CP) gene, an expected DNA fragment of about 872 bp was amplified from 10 of the 13 isolates. This fragment covered the CP open reading frame (ORF) plus 92 and 123 bp of the 5' and 3' flanking regions, respectively. Restriction analysis with MspI (HpaII) was done on 9 of the PCR products and revealed a previously described CMV subgroup I (S-I) specific profile (537 and 335 bp fragments) for the isolates B13, B23, B5, SH5, SH17, S342 and S337, and an additional fragment, suggestive of combined profiles, was present for B13, SH5 and S342. Two other isolates, SH12 and B7 had a CMV S-II MspI profile (four visible fragments and a predicted non-visible 28-bp fragment on 2% agarose). Also, BsuRI (HaeIII) did not cut the PCR products characteristic of the CMV S-I specific MspI profile, whereas for the S-II isolates, BsuRI gave two fragments with sizes of approximately 559 and 313 bp. Nucleotide (nt) sequences of clones from the isolates B13, B23, SH5, SH17, S337 and SH12 were determined and aligned with those of previously published CMV strains and isolates. Consensus parsimonious trees constructed on the basis of the whole amplified region (841 nt excluding the primer sequences), CP ORF (nt or deduced amino acid data), or

  5. Assessing the movement of Cucurbit yellow stunting disorder virus in susceptible and tolerant cucumber germplasms using serological and nucleic acid based methods

    Science.gov (United States)

    Cucurbit yellow stunting disorder virus (CYSDV) is an emerging virus causing significant yield losses in cucurbits. Simple but reliable detection and quantification methods constitute an important support to disease management. In a susceptible germplasm CYSDV was detected 5 days post-inoculation (D...

  6. Detection and quantitation of two cucurbit criniviruses in mixed infection by real-time RT-PCR.

    Science.gov (United States)

    Abrahamian, Peter E; Seblani, Rewa; Sobh, Hana; Abou-Jawdah, Yusuf

    2013-11-01

    Cucurbit chlorotic yellows virus (CCYV) and Cucurbit yellow stunting disorder virus (CYSDV) are whitefly-transmitted criniviruses infecting cucurbit crops inducing similar symptoms. Single and multiplex RT-PCR protocols were developed and evaluated on cucurbit samples collected from commercial greenhouses. Primers and probes were designed from the highly conserved heat shock protein 70 homolog (Hsp70h) gene. Conventional RT-PCR and multiplex RT-PCR assays showed high specificity and suitability for routine screening. TaqMan-based quantitative real-time RT-PCR (RT-qPCR) protocols were also developed for the detection and quantitation of both viruses occurring in single or mixed infection. The assays proved to be highly specific with no cross amplification. RT-qPCR assays showed a 100-1000 times improved sensitivity over conventional RT-PCR. Virus titers in mixed infections were compared to singly infected plants by RT-qPCR. CYSDV and CCYV titers decreased in double infected plants. This paper reports highly specific conventional RT-PCR and quantitative real-time PCR assays for detection, quantitation and differentiation between two closely related cucurbit-infecting criniviruses.

  7. Switching of emission of a styryl dye in cucurbit[7]uril: A comprehensive experimental and theoretical study

    Science.gov (United States)

    Manna, Anamika; Chakravorti, Sankar

    2015-04-01

    Intriguing colour change and change in fluorescence band of 2-(4-(dimethylamino)styryl)-1-methylpyridinium iodide from nonpolar to polar protic solvent, and also from molecular container cucurbit[7]uril environment to polar protic solvent has been reported here. This interesting colour change of this dye with respect to the medium makes this dye useful as a sensor. Change in spectral characteristics of DASPMI along with change of colour from orange to yellow with increasing polarity of medium is interpreted as due to negative solvatochromatism. Complexations of probe-cucurbit[7]uril (1:1 and 2:1) cause structural change of the probe molecule due to hydrogen bond interaction of cationic part of the dye with Cdbnd O group of cucurbit[7]uril and the colour change of the solution ensued. On addition of sodium chloride to the inclusion complex the dye is released from cucurbit[7]uril interior with colour of the solution reverted back. Theoretical results show that one carbon atom in the styryl part containing the positive charge gets too close to a carbon atom of cucurbit[7]uril to cause a phenomenal increase of dipole moment by 10X.

  8. Crumpled rGO-supported Pt-Ir bifunctional catalyst prepared by spray pyrolysis for unitized regenerative fuel cells

    Science.gov (United States)

    Kim, In Gyeom; Nah, In Wook; Oh, In-Hwan; Park, Sehkyu

    2017-10-01

    Three-dimensional (3D) crumpled reduced graphene oxide supported Pt-Ir alloys that served as bifunctional oxygen catalysts for use in untized regenerative fuel cells were synthesized by a facile spray pyrolysis method. Pt-Ir catalysts supported on rGO (Pt-Ir/rGOs) were physically characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA) to observe change in composition by heat treatment, alloying, and morphological transition of the catalysts. Their catalytic activities and stabilities for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) conditions were electrochemically investigated using cyclic voltammetry (CV), linear sweep voltammetry (LSV), potential cycling and hold tests on the rotating disk electrode (RDE). Pt-Ir/rGO with no post heat-treatment (Pt-Ir/rGO_NP) showed a lower activity for ORR and OER although metal nanoparticles decorated on the support are relatively small. However, Pt-Ir/rGO showed remarkably enhanced activity following heat treatment, depending on temperature. Pt-Ir/rGO heat-treated at 600 °C after spray pyrolysis (Pt-Ir/rGO_P600) exhibited a higher activity and stability than a commercially available Pt/C catalyst kept under the ORR condition, and it also revealed a comparable OER activity and durability versus the commercial unsupported Ir catalyst.

  9. Tomato yellow leaf curl viruses: ménage à trois between the virus complex, the plant and the whitefly vector.

    Science.gov (United States)

    Díaz-Pendón, Juan Antonio; Cañizares, M Carmen; Moriones, Enrique; Bejarano, Eduardo R; Czosnek, Henryk; Navas-Castillo, Jesús

    2010-07-01

    plants are stunted or dwarfed, with leaflets rolled upwards and inwards; young leaves are slightly chlorotic; in recently infected plants, fruits might not be produced or, if produced, are small and unmarketable. In common bean, some TYLCVs produce the bean leaf crumple disease, with thickening, epinasty, crumpling, blade reduction and upward curling of leaves, as well as abnormal shoot proliferation and internode reduction; the very small leaves result in a bushy appearance.

  10. Spatial and temporal diversity of begomoviral complexes in papayas with leaf curl disease.

    Science.gov (United States)

    Singh-Pant, P; Pant, P; Mukherjee, S K; Mazumdar-Leighton, S

    2012-07-01

    Old World, monopartite begomoviruses associated with satellite DNA β were observed in papaya showing symptoms of leaf curl disease sampled randomly over five years from within a radius of 250 km in north-central India. Three groups of DNA A sequences were evident. One group resembled chili leaf curl virus infecting tomatoes (ChiLCuV). Another group resembled tomato leaf curl New Delhi virus (ToLCuNDV). The third group was novel (tentatively named papaya leaf crumple virus, PaLCrV), with less than 89% identity to known begomovirus sequences in the GenBank database. At least seven DNA A sequences were putative recombinants. The AC4-encoding regions exhibited highest numbers of non-synonymous substitutions. Most DNA β sequences resembled tomato leaf curl virus-associated DNA βs. A few DNA β sequences were similar to that of croton yellow vein mosaic virus-associated DNA β (CroYVMVβ). One DNA β sequence was novel and showed papayas grown in plantations, kitchen gardens and feral patches in the region are vulnerable to disease outbreak. No geographic or temporal patterns were discernable in the distribution of these viruses.

  11. Binding Studies of Cucurbit[7]uril with Gold Nanoparticles Bearing Different Surface Functionalities.

    Science.gov (United States)

    Tonga, Gulen Yesilbag; Mizuhara, Tsukasa; Saha, Krishnendu; Jiang, Ziwen; Hou, Singyuk; Das, Riddha; Rotello, Vincent M

    2015-06-03

    Host-guest interactions between a synthetic receptor, cucurbit[7]uril (CB[7]), and gold nanoparticles (AuNPs) have been quantified using isothermal titration calorimetry. AuNPs were functionalized with ligands containing tertiary or quaternary benzylamine derivatives, with electron donating or withdrawing groups at the para position of the benzene ring. Analysis of binding interactions reveals that functional groups at the para position have no significant effect on binding constant. However, headgroups bearing a permanent positive charge increased the binding of AuNPs to CB[7] ten-fold compared to monomethyl counterparts.

  12. Taxonomic and functional diversity of cultured seed associated microbes of the cucurbit family.

    Science.gov (United States)

    Khalaf, Eman M; Raizada, Manish N

    2016-06-27

    Endophytes are microbes that colonize plant internal tissues without causing disease. In particular, seed-associated endophytes may be vectors for founder microbes that establish the plant microbiome, which may subsequently contribute beneficial functions to their host plants including nutrient acquisition and promotion of plant growth. The Cucurbitaceae family of gourds (e.g., cucumbers, melons, pumpkin, squash), including its fruits and seeds, is widely consumed by humans. However, there is limited data concerning the taxonomy and functions of seed-associated endophytes across the Cucurbitaceae family. Here, bacteria from surface-sterilized seeds of 21 curcurbit varieties belonging to seven economically important species were cultured, classified using 16S rRNA gene sequencing, and subjected to eight in vitro functional tests. In total, 169 unique seed-associated bacterial strains were cultured from selected cucurbit seeds. Interestingly, nearly all strains belonged to only two phyla (Firmicutes, Proteobacteria) and only one class within each phyla (Bacilli, γ-proteobacteria, respectively). Bacillus constituted 50 % of all strains and spanned all tested cucurbit species. Paenibacillus was the next most common genus, while strains of Enterobacteriaceae and lactic acid bacteria were also cultured. Phylogenetic trees showed limited taxonomic clustering of strains by host species. Surprisingly, 33 % of strains produced the plant hormone, indole-3-acetic acid (auxin), known to stimulate the growth of fruits/gourds and nutrient-acquiring roots. The next most common nutrient acquisition traits in vitro were (in rank order): nitrogen fixation/N-scavenging, phosphate solubilisation, siderophore secretion, and production of ACC deaminase. Secretion of extracellular enzymes required for nutrient acquisition, endophyte colonization and/or community establishment were observed. Bacillus strains had the potential to contribute all tested functional traits to their hosts

  13. Interaction of host-guest complexes of cucurbit[n]urils with double probe guests

    Institute of Scientific and Technical Information of China (English)

    MA; Peihua; DONG; Jun; XIANG; Shuangchun; XUE; Saifeng; ZH

    2004-01-01

    [1]Freeman, W. A., Mock, W. L., Shih, N. Y., Cucurbituril, J. Am.Chem. Soc., 1981, 103: 7367-7368.[2]Day, A. I., Arnold, A. P., Method for synthesis cucurbiturils, WO 0068232, 2000, 8.[3]Kim, J., Jung, I. S., Kim, S. Y. et al., New cucurbituril homologues: syntheses, isolation, characterization, and X-ray crystal structures of cucurbit[n]uril (n = 5, 7 and 8), J. Am. Chem. Soc.,2000, 122(3): 540-541.[4]Day, A. I., Blanck, R. J, Amold, A. P., A cucurbituril-based gyroscane: a new supramolecular form, Angew. Chem. Int. Ed., 2002,41(2): 275-277.[5]Blanck, R. J., Sleeman, A. J. White, T. J. et al., Cucurbit[7]uril and o-carborane self-assemble to form a molecular ball bearing,Nano. Lett., 2002, 2(2), 147-149.[6]Liu, J. X., Tao, Z., Xue, S. F. et al., Investigation of host-guest compounds of cucurbit[n = 5-8]uril with some piperazine derivatives, Chin. J. Inorg. Chem., 2004, 20(2): 139-147[7]Zhou, Y. L., Liu, Y., Inclusion complex of β-cyclodextrin and α-aminopyridine and its assembling behavior, Science in China,Ser. B, 2004, 34(1): 68-74.[8]Ong, W., Kaifer, A. E., Molecular encapsulation by cucurbit[7]uril of the apical 4,4'-bipyridinium residuein newkome-type dendrime,Angew. Chem. Inter. Ed., 2003, 42: 2164-2167.[9]Samsonenko, D. G., Gerasko, O. A., Mitkina, T. V. et al., Synthesis and crystal structure of supramolecular adducts of macrocyclic cavitand cucurbituril with chromium (Ⅲ) and nickel (Ⅱ) aqua complexes, Russian J. Coord. Chem. (Translation of Koordinatsionnaya Khimiya), 2003, 29(3): 166-174.[10]He, X. Y., Li, G., Chen, H. L., A new cucurbituril-based metallo-rotaxane, Inorg. Chem. Commun., 2002, (5): 633-641.[11]Fedin, V. P., Sokolov, M. N., Dybtsev, D. N. et al., Supramolecular assemblies of [Mo3Se4Clx(H2O)9-x](4-x)+ with cucurbituril;complementarity control through the variation of x, Inorg. Chim.Acta., 2002, 331(1): 31-38.[12]Lorenzo, S., Day, A., Craig, D. et al., The first endoannular metal halide

  14. Hierarchical networks of redox-active reduced crumpled graphene oxide and functionalized few-walled carbon nanotubes for rapid electrochemical energy storage

    Science.gov (United States)

    Lee, Byeongyong; Lee, Chongmin; Liu, Tianyuan; Eom, Kwangsup; Chen, Zhongming; Noda, Suguru; Fuller, Thomas F.; Jang, Hee Dong; Lee, Seung Woo

    2016-06-01

    Crumpled graphene is known to have a strong aggregation-resistive property due to its unique 3D morphology, providing a promising solution to prevent the restacking issue of graphene based electrode materials. Here, we demonstrate the utilization of redox-active oxygen functional groups on the partially reduced crumpled graphene oxide (r-CGO) for electrochemical energy storage applications. To effectively utilize the surface redox reactions of the functional groups, hierarchical networks of electrodes including r-CGO and functionalized few-walled carbon nanotubes (f-FWNTs) are assembled via a vacuum-filtration process, resulting in a 3D porous structure. These composite electrodes are employed as positive electrodes in Li-cells, delivering high gravimetric capacities of up to ~170 mA h g-1 with significantly enhanced rate-capability compared to the electrodes consisting of conventional 2D reduced graphene oxide and f-FWNTs. These results highlight the importance of microstructure design coupled with oxygen chemistry control, to maximize the surface redox reactions on functionalized graphene based electrodes.Crumpled graphene is known to have a strong aggregation-resistive property due to its unique 3D morphology, providing a promising solution to prevent the restacking issue of graphene based electrode materials. Here, we demonstrate the utilization of redox-active oxygen functional groups on the partially reduced crumpled graphene oxide (r-CGO) for electrochemical energy storage applications. To effectively utilize the surface redox reactions of the functional groups, hierarchical networks of electrodes including r-CGO and functionalized few-walled carbon nanotubes (f-FWNTs) are assembled via a vacuum-filtration process, resulting in a 3D porous structure. These composite electrodes are employed as positive electrodes in Li-cells, delivering high gravimetric capacities of up to ~170 mA h g-1 with significantly enhanced rate-capability compared to the electrodes

  15. Preparation of Crumpled Graphite Oxide from Recycled Graphite Using Plasma Electrolysis and Its Application for Adsorption of Cadmium in Aqueous Environment

    Science.gov (United States)

    Hong, Phan Ngoc; Tuoi, Tran Thi; Ngan, Nguyen Thi Kim; Trang, Bui Thi; Minh, Phan Ngoc; Lam, Tran Dai; Hanh, Nguyen Thi; Van Thanh, Dang

    2016-05-01

    Household battery waste is considered hazardous and needs to be collected, managed, and recycled appropriately. In this study, using a plasma electrolysis method, we recycled graphite electrodes of exhausted dry batteries to prepare crumpled graphite oxide (CGO). Scanning electron microscopy revealed that the CGO possessed spherical morphology with average dimensions of 0.5 μm to 5 μm. The as-prepared CGO was then applied to absorb cadmium in aqueous environment. The results showed that CGO appears to be a promising adsorbent for removal of toxic waste from polluted water.

  16. Supramolecular interaction of methotrexate with cucurbit[7]uril and analytical application

    Science.gov (United States)

    Chang, Yin-Xia; Zhang, Xiang-Mei; Duan, Xue-Chao; Liu, Fan; Du, Li-Ming

    2017-08-01

    The supramolecular interaction between cucurbit[7]uril (CB[7]) as the host and the anti-cancer drug methotrexate (MTX) as the guest was studied using fluorescence spectroscopy, UV-visible absorption spectroscopy, 1H NMR, 2D NOESY, and theoretical calculations. The experimental results confirmed the formation of 1:2 inclusion complex with CB[7] and indicated a simple and sensitive competitive method for the fluorescence detection of MTX. It was found that the fluorescence intensities of CB[7]-palmatine, CB[7]-berberine and CB[7]-coptisine were quenched linearly upon the addition of MTX. The linear ranges obtained in the detection of MTX were 0.1-15 μg mL- 1, 0.2-15 μg mL- 1, and 0.4-15 μg mL- 1 with detection limits of 0.03 μg mL-1, 0.06 μg mL-1, and 0.13 μg mL-1, respectively. This method can be used for the determination of MTX in biological fluids. These results suggested that cucurbit[7]uril is a promising drug carrier for targeted MTX delivery and monitoring, with improved efficacy and reduced toxicity in normal tissues.

  17. FLOWERING LOCUS T protein may act as the long-distance florigenic signal in the cucurbits.

    Science.gov (United States)

    Lin, Ming-Kuem; Belanger, Helene; Lee, Young-Jin; Varkonyi-Gasic, Erika; Taoka, Ken-Ichiro; Miura, Eriko; Xoconostle-Cázares, Beatriz; Gendler, Karla; Jorgensen, Richard A; Phinney, Brett; Lough, Tony J; Lucas, William J

    2007-05-01

    Cucurbita moschata, a cucurbit species responsive to inductive short-day (SD) photoperiods, and Zucchini yellow mosaic virus (ZYMV) were used to test whether long-distance movement of FLOWERING LOCUS T (FT) mRNA or FT is required for floral induction. Ectopic expression of FT by ZYMV was highly effective in mediating floral induction of long-day (LD)-treated plants. Moreover, the infection zone of ZYMV was far removed from floral meristems, suggesting that FT transcripts do not function as the florigenic signal in this system. Heterografting demonstrated efficient transmission of a florigenic signal from flowering Cucurbita maxima stocks to LD-grown C. moschata scions. Real-time RT-PCR performed on phloem sap collected from C. maxima stocks detected no FT transcripts, whereas mass spectrometry of phloem sap proteins revealed the presence of Cm-FTL1 and Cm-FTL2. Importantly, studies on LD- and SD-treated C. moschata plants established that Cmo-FTL1 and Cmo-FTL2 are regulated by photoperiod at the level of movement into the phloem and not by transcription. Finally, mass spectrometry of florally induced heterografted C. moschata scions revealed that C. maxima FT, but not FT mRNA, crossed the graft union in the phloem translocation stream. Collectively, these studies are consistent with FT functioning as a component of the florigenic signaling system in the cucurbits.

  18. MODULATION OF GROWTH AND PROTON PUMPING ATPase ACTIVITY OF PROBIOTIC Lactobacilli BY DIETARY CUCURBITS

    Directory of Open Access Journals (Sweden)

    Irfan Ahmad

    2013-12-01

    Full Text Available Gastrointestinal tract predominantly harbor probiotic Lactobacilli which exert beneficial effects on human health. Aqueous extracts from fruits of Lagenaria siceraria (Ls, Luffa cylindrica (Lc and Cucurbita maxima (Cm were prepared and lyophilized. Fruit extracts were investigated for their effects on Lactobacillus rhamnosus (L. rhamnosus, Lactobacillus plantarum (L. plantarum and Lactobacillus acidophilus (L. acidophilus. Extracts were found to enhance growth of Lactobacilli without any toxic effect (up to 1000µg/mL concentration. Minimum concentration of extracts at which growth of probiotic strains were found to be enhanced significantly were determined (103.67 µg/mL-118µg/mL and considered as effective concentration (EC or growth stimulatory concentration (GSC. Proton pumping ATPase activity of Lactobacilli were examined and found to be enhanced significantly (29.89- 61.96% in extracts treated probiotics (Lactobacilli as compared to the normal control. Inulin used as positive control and found to enhance the proton efflux activity (28.06-37.72% with respect to the control. These dietary cucurbits enhance metabolic activity of probiotic Lactobacilli by modulating their proton pumping ATPase mechanism. This study suggested that the consumption of cucurbit fruits might be a natural source of enhancing the activities of probiotic Lactobacilli in the gut.

  19. Response of cucurbit rootstocks for grafted melon (Cucumis melo) to southern root-knot nematode, Meloidogyne incognita

    Science.gov (United States)

    Root-knot nematodes (RKN) are an important re-emerging pest of melon (Cucumis melo), due largely to the loss of methyl bromide as a pre-plant soil fumigant. Melon is highly susceptible to southern RKN, Meloidogyne incognita, which causes severe root galling and reduced melon fruit yields. Cucurbit...

  20. Transmission of Squash vein yellowing virus to and From Cucurbit Weeds and Effects on Sweetpotato Whitefly (Hemiptera: Aleyrodidae) Behavior

    Science.gov (United States)

    Several common cucurbit weed reservoirs for Squash vein yellowing virus (SqVYV) were compared with watermelons as sources of inoculum. Weed susceptibility to SqVYV was also analyzed. In addition, behavior of the whitefly vector of SqVYV was studied on infected and non-infected plants. This report...

  1. First report of the cucurbit yellow vine disease caused by Serratia marcescens in watermelon and yellow squash in Alabama

    Science.gov (United States)

    Symptoms typical of cucurbit yellow vine disease (CYVD) were first observed in a 2 ha watermelon field in Crawford, Russell County, Alabama on 8 June 2010. Watermelon plants, cv. 'Jubilee,' exhibited a yellow or chlorotic appearance and some plants were completely wilted. On 24 June plant samples ...

  2. Reasoned opinion on the modification of the existing MRLs for cyprodinil in radishes and cucurbits inedible peel

    Directory of Open Access Journals (Sweden)

    European Food Safety Authority

    2013-04-01

    Full Text Available In accordance with Article 6 of Regulation (EC No 396/2005, the Netherlands, hereafter referred to as the evaluating Member State (EMS-NL, received an application from LTO Groeiservice to modify the existing MRL for the active substance cyprodinil in radish; a second application from the company Syngenta AGRO S.A.S to modify the existing MRL for the active substance cyprodinil in cucurbits, inedible peel was submitted to France (EMS-FR. In order to accommodate the intended uses of cyprodinil, EMSs proposed to raise the existing MRLs from the limit of quantification to 0.07 mg/kg for radish and to 0.6 mg/kg for cucurbits inedible peel. EMS-NL and EMS-FR drafted two evaluation reports in accordance with Article 8 of Regulation (EC No 396/2005, which were submitted to the European Commission and forwarded to EFSA. According to EFSA the data are sufficient to derive MRL proposals of 0.08 mg/kg for radish and of 0.6 mg/kg for cucurbits, inedible peel. Adequate analytical enforcement methods are available to control the residues of cyprodinil in radishes and cucurbits at the validated LOQ of 0.01 mg/kg. Based on the risk assessment results, EFSA concludes that the proposed use of cyprodinil on radish and cucurbits inedible peel under consideration will not result in a consumer exposure exceeding the toxicological reference value and therefore is unlikely to pose a consumer health risk.

  3. Preparation and lithium storage performance of nano Si/crumpled graphene composite material%纳米Si/褶皱石墨烯复合材料制备及储锂性能

    Institute of Scientific and Technical Information of China (English)

    李海; 吕春祥

    2015-01-01

    Crumpled graphene was prepared through freeze-drying, thermal annealing and HF treating the mixture suspension of graphene oxide and nano-SiO2. Nano-Si/crumpled graphene (SCG) composite material was prepared by dispersing nano-Si and crumpled graphene in ethanol solution and slowly drying the two materials. In SCG composite, Si nanoparticles were uniformly dispersed among crumpled graphene and surrounded by graphene networks. As the anode material for lithium ion batteries, the SCG exhibits high coulombic efficiency and good cycle stability of 1 003 mAh/g at the current density of 500 mA/g after 80 cycles. Such superior electrochemical perfor-mance should be attributed to high conductivity and good mechanical flexibility of crumpled graphene.%氧化石墨烯与纳米SiO2的混合悬浮液经过冷冻干燥、热退火和HF处理制得了褶皱石墨烯。将褶皱石墨烯与Si纳米颗粒在乙醇中分散后缓慢干燥制备了纳米Si/褶皱石墨烯(SCG)复合材料。Si纳米颗粒均匀分散于褶皱石墨烯中,并被石墨烯网络包围。作为锂离子电池负极材料,SCG具有高的库仑效率,在500 mA/g的电流密度下,80个循环后的比容量为1003 mAh/g,表现出良好的循环稳定性。如此优越的电化学性能要归因于褶皱石墨烯的高电导率和良好的机械柔韧性。

  4. Detection and quantitation of the new world Squash leaf curl virus by TaqMan real-time PCR.

    Science.gov (United States)

    Abrahamian, Peter E; Abou-Jawdah, Yusuf

    2013-07-01

    Squash leaf curl diseases are caused by distinct virus species that are separated into two major phylogenetic groups, western and eastern hemisphere groups. The western group includes the new world Squash leaf curl virus (SLCV) which causes major losses to cucurbit production and induces severe stunting and leaf curl in squash plants. A TaqMan-based real time polymerase chain reaction (qPCR) assay has been developed for detection and quantitation of SLCV. Designed primers and probe targeted the AV1 (coat protein) gene and in silico analysis showed that they detect a large number of SLCV isolates. The developed assay could detect the virus in 18fg of total nucleic acid and 30 genomic units. The qPCR assay was about 1000 times more sensitive than PCR and amplified successfully SLCV from a wide range of cucurbit hosts and from viruliferous whiteflies. The developed qPCR assay should be suitable for detection and quantitation purposes for all reported SLCV isolates of the western hemisphere.

  5. IDENTIFICATION AND EFFECTS OF MIXED INFECTION OF Potyvirus ISOLATES WITH Cucumber mosaic virus IN CUCURBITS

    Directory of Open Access Journals (Sweden)

    GRAZIELA DA SILVA BARBOSA

    2016-01-01

    Full Text Available Mixed infections in cucurbits are frequently observed in natural conditions between viruses from the Potyvirus genus and Cucumber mosaic virus (CMV, which significantly decreases productivity. The objectives of the present study was to compare the host range of PRSV - W, WMV, and ZYMV isolates and evaluate the effects of mixed infections with CMV in zucchini plants ( Cucurbita pepo L.. Host range studies comprising 23 plant species confirmed some similarities and biological differences among the isolates of PRSV - W, ZYMV, and WMV. RT - PCR confirmed the amplification of DNA fragments of the PRSV - W, WMV, and ZYMV coat protein gene ( cp and cytoplasm inclusion gene ( ci . The virus interaction studies in zucchini Caserta plants indicated synergistic interactions, particularly among species from the Potyvirus genus, and some CMV interference with some virus combinations.

  6. Spectroscopy and laser characterization of synthesized supramolecular host cucurbit[7]uril using aqueous Rhodamine B dye

    Indian Academy of Sciences (India)

    Deepak R Boraste; Monika Gupta; Ganapati Shankarling; Alok K Ray; Sandip K Nayak

    2014-02-01

    Recent demonstration in augmenting the efficiency of aqueous Rhodamine dye lasers using cucurbit[7]uril (CB[7]), a deaggregating and photostabilizing host, has drawn interest in the synthesis and characterization of spectroscopic grade CB[7] in larger quantities. Synthesis of cucurbituril group of macrocycles always leads to the formation of various homologues of CB[n]s (n=5–7) with CB[7] as the minor product. The literature procedure has been optimized to get pure CB[7] in 12–14% yield by fractional crystallization and the purity was checked by NMR, MS and spectrophotometric titration. Laser performances of the synthesized and commercial CB[7] sample as an additive were evaluated using Nd-YAG (532 nm) pumped Rhodamine B aqueous dye lasers and comparable results were obtained.

  7. Supramolecular Encapsulation of Vitamin B6 by Macrocyclic Nanocontainer Cucurbit[7]uril

    Directory of Open Access Journals (Sweden)

    Wanying Li

    2015-01-01

    Full Text Available A pharmaceutically and biologically relevant molecule, pyridoxine hydrochloride (vitamin B6, was encapsulated inside the cavity of a molecular container, cucurbit[7]uril (CB[7], in aqueous solution. The CB[7] based “nanocapsule” of vitamin B6 has been investigated for the first time, via 1H NMR and UV-visible spectroscopic titrations (including Job’s plot and ab initio molecular modeling. The results have demonstrated that vitamin B6 forms stable host-guest complexes within CB[7] in 1 : 1 stoichiometry, with a binding affinity of (4.0±0.5×103 M−1. Such a nanocapsule could potentially find application in vitamin B6 formulation for the purpose of enhancing the stability, absorption, and delivery of this important vitamin.

  8. Electrostatic repulsion between cucurbit[7]urils can be overcome in [3]pseudorotaxane without adding salts.

    Science.gov (United States)

    Pessêgo, M; Moreira, J A; Rosa da Costa, A M; Corrochano, P; Poblete, F J; Garcia-Rio, L

    2013-04-19

    The host-guest chemistry between cucurbit[7]uril (CB7) and a series of bolaform (Bn) surfactants with different chain lengths, n = 12-22, was the target of our study. [3]Pseudorotaxanes are formed when the alkyl chain of the bolaform has more than 14 carbon atoms. In these cases, two CB7 molecules can be accommodated between the two head groups of the bolaform without addition of electrolytes to the medium. In the case of a bolaform with 12 carbon atoms, the electrostatic repulsion between the carbonyl groups of the CB7 molecules avoids the threading of a second CB7 molecule yielding a mixed structure formed by a [2]pseudorotaxane and an external host-guest complex. The assembly behavior was investigated using NMR spectroscopy, isothermal titration calorimetry (ITC), and kinetic measurements.

  9. Biodegradation of aliphatic hydrocarbons in the presence of hydroxy cucurbit[6]uril.

    Science.gov (United States)

    Pasumarthi, Rajesh; Kumar, Vikash; Chandrasekharan, Sivaraman; Ganguly, Anasuya; Banerjee, Mainak; Mutnuri, Srikanth

    2014-11-15

    Aliphatic hydrocarbons are one of the major environmental pollutants with reduced bioavailability. The present study focuses on the effect of hydroxy cucurbit[6]uril on the bioavailability of hydrocarbons. A bacterial consortium was used for biodegradation studies under saline and non-saline conditions. Based on denaturing gradient gel electrophoresis results it was found that the consortium under saline conditions had two different strains. The experiment was conducted in microcosms with tetradecane, hexadecane, octadecane and mixture of the mentioned hydrocarbons as the sole carbon source. The residual hydrocarbon was quantified using gas chromatography every 24h. It was found that biodegradation of tetradecane and hexadecane, as individual carbon source increased in the presence of hydroxy CB[6], probably due to the increase in their bioavailability. In case of octadecane this did not happen. Bioavailability of all three aliphatic hydrocarbons was increased when provided as a mixture to the consortium under saline conditions.

  10. Determination of L-phenylalanine by cucurbit[7]uril sensitized fluorescence quenching method

    Institute of Scientific and Technical Information of China (English)

    Chang Feng Li; Li Ming Du; Hao Wu; Ying Xia Chang

    2011-01-01

    The determination method of L-phenylalanine (LPA) by fluorescence quenching was developed. The assay was based on the combination of the cucurbit[7]uril (CB[7]) with palmatine hydrochloride (PAL) reaction. In the presence of CB[7], the fluorescence of PAL was quenched by LPA which can be employed to detect LPA. Under the optimal conditions, a linear range 3.63 × 10-8-9.68 × 10-6 mol/L and a detection limit 1.27 × 10-8 mol/L of LPA were obtained. The relative standard deviation (R.S.D) was 1.8% obtained from a series of11 standards each containing 6.05 × 10-6 mol/L oLPA. This paper also discusses the mechanism of fluorescence indicator probe.

  11. Cedar leaf oil poisoning

    Science.gov (United States)

    Cedar leaf oil is made from some types of cedar trees. Cedar leaf oil poisoning occurs when someone swallows this substance. ... The substance in cedar leaf oil that can be harmful is thujone (a hydrocarbon).

  12. Molecular characterization and phylogenetic relationships of Desmodium leaf distortion virus (DeLDV): a new begomovirus infecting Desmodium glabrum in Yucatan, Mexico.

    Science.gov (United States)

    Hernández-Zepeda, Cecilia; Argüello-Astorga, Gerardo; Idris, Ali M; Carnevali, Germán; Brown, Judith K; Moreno-Valenzuela, Oscar A

    2009-12-01

    The complete DNA-A component sequence of Desmodium leaf distortion virus (DeLDV, Begomovirus) isolated in Yucatan was determined to be 2569 nucleotides (nt) in length, and it was most closely related to Cotton leaf crumple virus-California (CLCrV-[Cal]), at 76%. The complete DNA-B component sequence was 2514 nt in length, and shared its highest nucleotide identity (60%) with Potato yellow mosaic Trinidad virus (PYMTV). Phylogenetic analyses group the DeLDV DNA-A component in the SLCV clade, whereas, the DeLDV DNA-B was grouped with the Abutilon mosaic virus clade, which also contains PYMV, suggesting that the DeLDV components have distinct evolutionary histories, possibly as the result of recombination and reassortment.

  13. Leaf Collection Posting Log

    Data.gov (United States)

    Montgomery County of Maryland — This dataset contains leaf collection dates for area and subarea where leaf collection service is provided by Montgomery County Department of Transportation. Update...

  14. Seletividade do herbicida fluazifop-p-butil para cucurbitáceas Selectivity of the herbicide fluazifop-p-buthyl for cucurbitaceae

    Directory of Open Access Journals (Sweden)

    R.A. Vidal

    2000-01-01

    Full Text Available Experimentos foram conduzidos em condições de casa de vegetação, com o objetivo de avaliar a seletividade do herbicida fluazifop-p-butil nas doses de 0, 94, 188, 376 e 752 g i.a. ha-1 para cinco espécies de cucurbitáceas (abobrinha, melancia, melão, moranga e pepino. Foi determinada a fitotoxicidade aos 14 dias após a aplicação dos tratamentos (DAT. Aos 20 DAT foram avaliadas a estatura, área foliar e matéria seca. O melão e o pepino mostraram sensibilidade ao fluazifop-p-butil na maior dose estudada, com maior intensidade no melão. Os resultados demonstraram que existe resposta a estes herbicidas mesmo dentro da classe Dicotiledoneae. Especula-se que essas respostas possam auxiliar no entendimento do completo mecanismo de ação desse herbicida.Experiments were conducted under greenhouse conditions to evaluate the selectivity of the herbicide fluazifop-p-buthyl at rates of 0, 94, 188 and 752 g a.i. ha-1 for five cucurbitaceous species (summer squash, watermelon, melon, pumpkin and cucumber. Plant injury at 14 days after treatments (DAT and plant size, leaf area and dry weight at 20 DAT were determined. Melon and cucumber were susceptible to fluazifop-p-buthyl at the highest rate with highest herbicide effect being observed on melon. These results indicated that responses to these herbicides occur, even in the Dicotiledonae class. These responses are thought to help understand the overall mechanism of action of this herbicide.

  15. Advanced Sulfur Cathode Enabled by Highly Crumpled Nitrogen-Doped Graphene Sheets for High-Energy-Density Lithium-Sulfur Batteries.

    Science.gov (United States)

    Song, Jiangxuan; Yu, Zhaoxin; Gordin, Mikhail L; Wang, Donghai

    2016-02-10

    Herein, we report a synthesis of highly crumpled nitrogen-doped graphene sheets with ultrahigh pore volume (5.4 cm(3)/g) via a simple thermally induced expansion strategy in absence of any templates. The wrinkled graphene sheets are interwoven rather than stacked, enabling rich nitrogen-containing active sites. Benefiting from the unique pore structure and nitrogen-doping induced strong polysulfide adsorption ability, lithium-sulfur battery cells using these wrinkled graphene sheets as both sulfur host and interlayer achieved a high capacity of ∼1000 mAh/g and exceptional cycling stability even at high sulfur content (≥80 wt %) and sulfur loading (5 mg sulfur/cm(2)). The high specific capacity together with the high sulfur loading push the areal capacity of sulfur cathodes to ∼5 mAh/cm(2), which is outstanding compared to other recently developed sulfur cathodes and ideal for practical applications.

  16. Establishment of a Simple and Rapid Gene Delivery System for Cucurbits by Using Engineered of Zucchini yellow mosaic virus.

    Science.gov (United States)

    Kang, Minji; Seo, Jang-Kyun; Choi, Hoseong; Choi, Hong-Soo; Kim, Kook-Hyung

    2016-02-01

    The infectious full-length cDNA clone of zucchini yellow mosaic virus (ZYMV) isolate PA (pZYMV-PA), which was isolated from pumpkin, was constructed by utilizing viral transcription and processing signals to produce infectious in vivo transcripts. Simple rub-inoculation of plasmid DNAs of pZYMV-PA was successful to cause infection of zucchini plants (Cucurbita pepo L.). We further engineered this infectious cDNA clone of ZYMV as a viral vector for systemic expression of heterologous proteins in cucurbits. We successfully expressed two reporter genes including gfp and bar in zucchini plants by simple rub-inoculation of plasmid DNAs of the ZYMV-based expression constructs. Our method of the ZYMV-based viral vector in association with the simple rub-inoculation provides an easy and rapid approach for introduction and evaluation of heterologous genes in cucurbits.

  17. Reasoned opinion on the modification of the existing MRLs for proquinazid in tomatoes, aubergines and cucurbits with edible peel

    Directory of Open Access Journals (Sweden)

    European Food Safety Authority

    2012-09-01

    Full Text Available

    In accordance with Article 6 of Regulation (EC No 396/2005, Germany, hereafter referred to as the evaluating Member State (EMS, received two applications from Pflanzenschutzdienst der Landwirtschaftskammer Nordrhein-Westfalen to modify the existing MRLs for the active substance proquinazid in tomatoes and aubergines and in cucurbits (edible peel, respectively. In order to accommodate for the intended uses of proquinazid, Germany proposed to raise the existing MRLs from the limit of quantification (LOQ of 0.02 mg/kg to 0.15 mg/kg in tomatoes and aubergines and to 0.04 mg/kg in cucurbits with edible peel. Germany drafted two separate evaluation reports in accordance with Article 8 of Regulation (EC No 396/2005, which were submitted to the European Commission and forwarded to EFSA. For reasons of efficiency EFSA combined both applications in one reasoned opinion. According to EFSA the data are sufficient to derive MRL proposals of 0.15 mg/kg for the intended use on tomatoes and aubergines and of 0.05 mg/kg for the intended use on the whole group of cucurbits (edible peel. Adequate analytical enforcement methods are available to control the residues of proquinazid in the crops under consideration. Based on the risk assessment results, EFSA concludes that the proposed use of proquinazid on tomatoes, aubergines and cucurbits with edible peel will not result in a consumer exposure exceeding the toxicological reference values and therefore is unlikely to pose a consumer health risk.

  18. Reasoned opinion on the modification of the existing MRLs for difenoconazole in raspberries, blackberries and cucurbits (edible peel

    Directory of Open Access Journals (Sweden)

    European Food Safety Authority

    2012-08-01

    Full Text Available

    In accordance with Article 6 of Regulation (EC No 396/2005, Germany, hereafter referred to as the evaluating Member State (EMS, received an application from TSGE Deutschland GmbH to modify the existing MRLs for difenoconazole in raspberries and blackberries. Germany also received an application from Landwirtschaftskammer NRW Pflanzenschutzdienst to modify the existing MRLs for difenoconazole in cucurbits with (edible peel. In order to accommodate the intended NEU outdoor use on raspberries and blackberries and the intended indoor use on cucurbits (edible peel, the EMS proposed to raise the existing MRLs in these berries from 0.3 mg/kg to 1.5 mg/kg and in cucurbits (edible peel from 0.1 mg/kg to 0.3 mg/kg. The EMS drafted two evaluation reports in accordance with Article 8 of Regulation (EC No 396/2005, which were submitted to the European Commission and forwarded to EFSA. According to EFSA, the applications are sufficiently supported by data and EFSA confirmed the MRL proposals made by the EMS. Adequate analytical enforcement methods are available to control the residues of difenoconazole in the crops under consideration. The risk assessment demonstrated that the intended use of difenoconazole on the crops under consideration will not result in a consumer exposure exceeding the toxicological reference values and therefore is unlikely to pose a public health concern.

  19. Cucurbit[7]uril⋅guest pair with an attomolar dissociation constant.

    Science.gov (United States)

    Cao, Liping; Śekutor, Marina; Zavalij, Peter Y; Mlinarić-Majerski, Kata; Glaser, Robert; Isaacs, Lyle

    2014-01-20

    Host⋅guest complexes between cucurbit[7] (CB[7]) or CB[8] and diamantane diammonium ion guests 3 or 6 were studied by (1) H NMR spectroscopy and X-ray crystallography. (1) H NMR competition experiments revealed that CB[7]⋅6 is among the tightest monovalent non-covalent complexes ever reported in water with Ka =7.2×10(17)  M(-1) in pure D2 O and 1.9×10(15)  M(-1) in D2 O buffered with NaO2 CCD3 (50 mM). The crystal structure of CB[7]⋅6 allowed us to identify some of the structural features responsible for the ultratight binding, including the distance between the NMe3 (+) groups of 6 (7.78 Å), which allows it to establish 14 optimal ion-dipole interactions with CB[7], the complementarity of the convex van der Waals surface contours of 6 with the corresponding concave surfaces of CB[7], desolvation of the CO portals within the CB[7]⋅6 complex, and the co-linearity of the C7  axis of CB[7] with the N(+) ⋅⋅⋅N(+) line in 6. This work further blurs the lines of distinction between natural and synthetic receptors.

  20. Occurrence and molecular characterization of Cucumber green mottle mosaic virus in cucurbit crops of KPK, Pakistan

    Directory of Open Access Journals (Sweden)

    Asad Ali

    2014-12-01

    Full Text Available Field survey of the cucurbit crops revealed a high incidence of Cucumber green mottle mosaic virus (CGMMV in Khyber Pakhtunkhwa Province (KPK, Pakistan. Among the seven districts surveyed, average percent incidence of CGMMV was recorded up to 58.1% in district Nowshera, followed by 51.1% in district Charsada, 40.5% in district Swabi and 37.3% in district Mardan. In Swat and Dir districts average incidence CGMMV was recorded upto 31.2% and 29.4%, respectively. Among the different crops highest incidence in plain areas of KPK was recorded in bottle gourd (59.3% followed by 56.3% in Squash, 54.5% in Pumpkin, 45.5% in Melon, 41.7% in Cucumber and 29.9% in Sponge gourd. In Northern hilly areas highest incidence of CGMMV (52.9% was observed in pumpkin, followed by 49.6% in bottle gourd, 47.3% in squash, 45.1% in Melon 42.3% in cucumber and 41.6% in sponge gourd. Little variability was observed in the coat protein amino acid sequence identities of CGMMV Pakistan isolate, when compared with other reported isolates.

  1. Biocontrol agent Bacillus amyloliquefaciens LJ02 induces systemic resistance against cucurbits powdery mildew.

    Science.gov (United States)

    Li, Yunlong; Gu, Yilin; Li, Juan; Xu, Mingzhu; Wei, Qing; Wang, Yuanhong

    2015-01-01

    Powdery mildew is a fungal disease found in a wide range of plants and can significantly reduce crop yields. Bacterial strain LJ02 is a biocontrol agent (BCA) isolated from a greenhouse in Tianjin, China. In combination of morphological, physiological, biochemical and phylogenetic analyses, strain LJ02 was classified as a new member of Bacillus amyloliquefaciens. Greenhouse trials showed that LJ02 fermentation broth (LJ02FB) can effectively diminish the occurrence of cucurbits powdery mildew. When treated with LJ02FB, cucumber seedlings produced significantly elevated production of superoxide dismutase, peroxidase, polyphenol oxidase and phenylalanine ammonia lyase as compared to that of the control. We further confirmed that the production of free salicylic acid (SA) and expression of one pathogenesis-related (PR) gene PR-1 in cucumber leaves were markedly elevated after treating with LJ02FB, suggesting that SA-mediated defense response was stimulated. Moreover, LJ02FB-treated cucumber leaves could secrete resistance-related substances into rhizosphere that inhibit the germination of fungi spores and the growth of pathogens. Finally, we separated bacterium and its fermented substances to test their respective effects and found that both components have SA-inducing activity and bacterium plays major roles. Altogether, we identified a BCA against powdery mildew and its mode of action by inducing systemic resistance such as SA signaling pathway.

  2. Transformation of the cucurbit powdery mildew pathogen Podosphaera xanthii by Agrobacterium tumefaciens.

    Science.gov (United States)

    Martínez-Cruz, Jesús; Romero, Diego; de Vicente, Antonio; Pérez-García, Alejandro

    2017-03-01

    The obligate biotrophic fungal pathogen Podosphaera xanthii is the main causal agent of powdery mildew in cucurbit crops all over the world. A major limitation of molecular studies of powdery mildew fungi (Erysiphales) is their genetic intractability. In this work, we describe a robust method based on the promiscuous transformation ability of Agrobacterium tumefaciens for reliable transformation of P. xanthii. The A. tumefaciens-mediated transformation (ATMT) system yielded transformants of P. xanthii with diverse transferred DNA (T-DNA) constructs. Analysis of the resultant transformants showed the random integration of T-DNA into the P. xanthii genome. The integrations were maintained in successive generations in the presence of selection pressure. Transformation was found to be transient, because in the absence of selection agent, the introduced genetic markers were lost due to excision of T-DNA from the genome. The ATMT system represents a potent tool for genetic manipulation of P. xanthii and will likely be useful for studying other biotrophic fungi. We hope that this method will contribute to the development of detailed molecular studies of the intimate interaction established between powdery mildew fungi and their host plants.

  3. Chemical composition of Apodanthera biflora, a Cucurbit of the dry forest in northwestern Peru

    Directory of Open Access Journals (Sweden)

    Daniel Clark

    2012-11-01

    Full Text Available The dry forest of northwestern Peru is the habitat of numerous native species that have received little attention beyond taxonomic purposes. Here we report the chemical composition of the roots and seeds of a set of accessions of Apondanthera biflora, a wild Cucurbit with potentialities as a food resource. The roots show features that are comparable to those from cassava roots and potato tubers: a high content of carbohydrates on a dry matter basis (77.5 – 84.9%, with starch representing around 20% of the total dry matter. The seeds’ fat content on a dry matter basis (22.22 – 39.37% falls within the percentages found in oily seeds such as safflower, whereas the protein content (21.37 – 29.06% is similar to that of flax and sunflower. The fatty acid profile of the seed’s oil shows a predominance of polyunsaturated acids, in particular linoleic acid (43.81%, making it comparable to that of cotton oil. Our results confirm the nutritional value of Apodanthera biflora and set the ground for its use in domestication and food security programs.

  4. Study on the inclusion interactions of berberine hydrochloride and cucurbit[7] by spectrofluorimetry

    Institute of Scientific and Technical Information of China (English)

    Yan Ping Li; Hao Wu; Li Ming Du

    2009-01-01

    The inclusion interaction between berberine hydrochloride (BRH) and cucurbit[7] (CB[7]) has been studied by spectro-fluorimetry. The result showed that CB[7] interaction with BRH to form a stable inclusion complex with an association constant of 9.57 x 104 L/tool and the fluorescence intensity of the complex was enhanced in 17 times higher than that of the studied drug itself.Based on the significant enhancement of fluorescence intensity of BRH in inclusion complex, a spetrofluodmetric method with high sensitivity and selectivity was developed for the determination of BRH in aqueous solution. The linear range of the method was 3.2-2 x 103 ng]mL with a detection limit of 1.1 ng/mL. The proposed procedure could be applied successfully to determination of BRH remained in pharmaceutical dosage forms, spiked human plasma and urine with satisfactory results.(C) 2008 Li Ming Du. Published by Elsevier B.V. On behalf of Chinese Chemical Society. All rights reserved.

  5. Supramolecular Adducts of Cucurbit[7]uril and Amino Acids in the Gas Phase

    Science.gov (United States)

    Kovalenko, Ekaterina; Vilaseca, Marta; Díaz-Lobo, Mireia; Masliy, A. N.; Vicent, Cristian; Fedin, Vladimir P.

    2016-02-01

    The complexation of the macrocyclic cavitand cucurbit[7]uril (Q7) with a series of amino acids (AA) with different side chains (Asp, Asn, Gln, Ser, Ala, Val, and Ile) is investigated by ESI-MS techniques. The 1:1 [Q7 + AA + 2H]2+ adducts are observed as the base peak when equimolar Q7:AA solutions are electrosprayed, whereas the 1:2 [Q7 + 2AA + 2H]2+ dications are dominant when an excess of the amino acid is used. A combination of ion mobility mass spectrometry (IM-MS) and DFT calculations of the 1:1 [Q7 + AA + 2H]2+ (AA = Tyr, Val, and Ser) adducts is also reported and proven to be unsuccessful at discriminating between exclusion or inclusion-type conformations in the gas phase. Collision induced dissociation (CID) revealed that the preferred dissociation pathways of the 1:1 [Q7 + AA + 2H]2+ dications are strongly influenced by the identity of the amino acid side chain, whereas ion molecule reactions towards N-butylmethylamine displayed a common reactivity pattern comprising AA displacement. Special emphasis is given on the differences between the gas-phase behavior of the supramolecular adducts with amino acids (AA = Asp, Asn, Gln, Ser, Ala, Val, and Ile) and those featuring basic (Lys and Arg) and aromatic (Tyr and Phe) side chains.

  6. Encapsulation of the ethylene inhibitor 1-Methylcyclopropene by cucurbit[6]uril.

    Science.gov (United States)

    Zhang, Quan; Zhen, Zeng; Jiang, Hong; Li, Xue-Gang; Liu, Jun-An

    2011-10-12

    1-Methylcyclopropene (1-MCP) is an excellent safe and commercially available ethylene antagonist for the preservation of horticultural products. However 1-MCP has to be stored in absorbents due to its gaseous and unstable characteristics. In this paper cucurbit[6]uril (CB[6]) was used as the absorbent to encapsulate 1-MCP, and the resultant inclusion complex was characterized by IR, powder X-ray diffraction, thermal analysis, and fluorescent spectra. The effects of encapsulation conditions on the formation of inclusion complex were also investigated. The amount of 1-MCP encapsulated by CB[6] was about 4.5% by weight when the initial concentration of 1-MCP, encapsulation temperature, CB[6] concentration, and encapsulation time were set at 75 mL/L, 20 °C, 30 mM, and 8 h, respectively. Furthermore, the release of 1-MCP from the complex can be realized with different solutions such as sodium bicarbonate, benzoic acid, and distilled water. CB[6] can be used as an excellent absorbent for encapsulation of 1-MCP.

  7. Fluorescence detecting of paraquat using host-guest chemistry with cucurbit[8]uril

    Science.gov (United States)

    Sun, Shiguo; Li, Fusheng; Liu, Fengyu; Wang, Jitao; Peng, Xiaojun

    2014-01-01

    Paraquat (PQ) is one of the most widely used herbicides in the world, which has a good occupational safety record when used properly. While, it presents high mortality index after intentional exposure. Accidental deaths and suicides from PQ ingestion are relatively common in developing countries with an estimated 300,000 deaths occurring in the Asia-Pacific region alone each year, and there are no specific antidotes. Good predictors of outcome and prognosis may be plasma and urine testing within the first 24 h of intoxication. A fluorescence enhancement of approximately 30 times was seen following addition of PQ to a solution of the supramolecular compound 2MB@CB[8], which comprised two methylene blue (MB) molecules within one cucurbit[8]uril (CB[8]) host molecule. The fluorescence intensity was linearly proportional to the amount of PQ added over the concentration range 2.4 × 10-10 M-2.5 × 10-4 M. The reaction also occurred in living cells and within live mice.

  8. Resistance to Cucurbit aphid-borne yellows virus in Melon Accession TGR-1551.

    Science.gov (United States)

    Kassem, Mona A; Gosalvez, Blanca; Garzo, Elisa; Fereres, Alberto; Gómez-Guillamón, Maria Luisa; Aranda, Miguel A

    2015-10-01

    The genetic control of resistance to Cucurbit aphid-borne yellows virus (CABYV; genus Polerovirus, family Luteoviridae) in the TGR-1551 melon accession was studied through agroinoculation of a genetic family obtained from the cross between this accession and the susceptible Spanish cultivar 'Bola de Oro'. Segregation analyses were consistent with the hypothesis that one dominant gene and at least two more modifier genes confer resistance; one of these additional genes is likely present in the susceptible parent 'Bola de Oro'. Local and systemic accumulation of the virus was analyzed in a time course experiment, showing that TGR-1551 resistance was expressed systemically as a significant reduction of virus accumulation compared with susceptible controls, but not locally in agroinoculated cotyledons. In aphid transmission experiments, CABYV inoculation by aphids was significantly reduced in TGR-1551 plants, although the virus was acquired at a similar rate from TGR-1551 as from susceptible plants. Results of feeding behavior studies using the DC electrical penetration graph technique suggested that viruliferous aphids can salivate and feed from the phloem of TGR-1551 plants and that the observed reduction in virus transmission efficiency is not related to reduced salivation by Aphis gossypii in phloem sieve elements. Since the virus is able to accumulate to normal levels in agroinoculated tissues, our results suggest that resistance of TGR-1551 plants to CABYV is related to impairment of virus movement or translocation after it reaches the phloem sieve elements.

  9. Cucurbit[7]uril host-guest complexes of the histamine H2-receptor antagonist ranitidine.

    Science.gov (United States)

    Wang, Ruibing; Macartney, Donal H

    2008-06-07

    The macrocyclic host cucurbit[7]uril forms very stable complexes with the diprotonated (K(CB[7])(1) = 1.8 x 10(8) dm(3) mol(-1)), monoprotonated (K(CB[7])(2) = 1.0 x 10(7) dm(3) mol(-1)), and neutral (K(CB[7])(3) = 1.2 x 10(3) dm(3) mol(-1)) forms of the histamine H(2)-receptor antagonist ranitidine in aqueous solution. The complexation behaviour was investigated using (1)H NMR and UV-visible spectroscopy as a function of pH and the pK(a) values of the guest were observed to increase (DeltapK(a1) = 1.5 and DeltapK(a2) = 1.6) upon host-guest complex formation. The energy-minimized structures of the host-guest complexes with the cationic guests were determined and provide agreement with the NMR results indicating the location of the CB[7] over the central portion of the guest. The inclusion of the monoprotonated form of ranitidine slows the normally rapid (E)-(Z) exchange process and generates a preference for the (Z) isomer. The formation of the CB[7] host-guest complex greatly increases the thermal stability of ranitidine in acidic aqueous solution at 50 degrees C, but has no effect on its photochemical reactivity.

  10. Ketoprofen encapsulated cucurbit[6]uril nanoparticles: a new exploration of macrocycles for drug delivery

    Science.gov (United States)

    Hoai, Nguyen To; Tuyen Thi Dao, Phuong; Phu, Quoc Nam; Dam Le, Duy; Nguyen, Tuan Anh; Nguyen, Tai Chi; Chien Dang, Mau

    2012-12-01

    The aim of this study is (i) to fabricate a nanoparticle formulation of ketoprofen (Keto) using a relatively new family of macrocycles as the carrier for drug delivery: cucurbit[6]uril (CB[6]), (ii) to evaluate its in vitro dissolution and (iii) to investigate its in vivo pharmaceutical property. The CB[6]-Keto nanoparticles were prepared by emulsion solvent evaporation method. Morphology and size of the successfully prepared nanoparticles were then confirmed using a transmission electron microscope and dynamic light scattering. It was shown that they are spherical with hydrodynamic diameter of 200-300 nm. The in vitro dissolution studies of CB[6]-Keto nanoparticles were conducted at pH 1.2 and 7.4. The results indicated that there is a significant increase in Keto concentration at pH 7.4 compared to pH 1.2. For the in vivo assessment, CB[6]-Keto nanoparticles and referential profenid were administered by oral gavages to rabbits. The results implied that CB[6]-Keto nanoparticles remarkably increased area under the curve compared to profenid.

  11. Cucurbit[6]uril nanocavity as an enhanced spectrofluorimetric method for the determination of pyrene

    Energy Technology Data Exchange (ETDEWEB)

    Sueldo Occello, Valeria N. [Instituto de Investigaciones en Fisico Quimica de Cordoba (INFIQC), Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina); Veglia, Alicia V., E-mail: aveglia@fcq.unc.edu.ar [Instituto de Investigaciones en Fisico Quimica de Cordoba (INFIQC), Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina)

    2011-03-09

    The effect of the addition of macrocyclic host cucurbit[6]uril (CB6) on the photophysical properties of polycyclic aromatic hydrocarbon pyrene (PYR) was analyzed. The fluorescence emission spectra of the aromatic compound were determined at 25.0 {sup o}C in different acidic media (HCl 18%, w/v, or HCOOH 55%, w/v) with and without CB6. A significant enhancement in the fluorescence signals in the presence of CB6 was observed. The average values of the association constant (K{sub A}) for the 1:1 stoichiometry complex and the relative fluorescence quantum yield ratio between the complexed and free PYR ({phi}{sup PYR-CB6}/{phi}{sup PYR}) in acidic media were (4.0 {+-} 0.5) x 10{sup 2} M{sup -1} and (5.7 {+-} 0.2), respectively. The analytical parameters improved in the presence of CB6. The relative decrease in the limit of detection was 92%. The matrix effect was evaluated in fortified samples of tap water and tea extracts. Apparent recoveries obtained by the proposed method in tap water and tea extracts were (82-103)% and (89-99)%, respectively. Selectivity studies with inorganic and organic species were performed. The method is rapid, direct, selective and simple.

  12. Host-guest complexes and pseudorotaxanes of cucurbit[7]uril with acetylcholinesterase inhibitors.

    Science.gov (United States)

    Wyman, Ian W; Macartney, Donal H

    2009-11-06

    Pseudorotaxanes may be assembled in aqueous solution using dicationic acetylcholinesterase inhibitors, such as succinylcholine, BW284c51, and alpha,omega-bis(trialkylammonium)alkane dications (or their phosphonium analogues), as bolaform axles and cucurbit[7]uril (CB[7]) as the wheel. With the exceptions of the shorter [(CH(3))(3)N(CH(2))(n)N(CH(3))(3)](2+) (n = 6, 8) dications, the addition of a second CB[7] results in the translocation of the first CB[7], such that the hydrophobic -NR(3)(+) and -PR(3)(+) end groups (R = Me or Et) are located in the cavities of the wheels, while the central portion of the axles extend through the CB[7] portals into the bulk solvent. In the case of the [Quin(CH(2))(10)Quin](2+) (Quin = quinuclidinium) dication, the CB[7] host(s) resides only on the quinuclidinium end group(s). The 1:1 host-guest stability constants range from 8 x 10(6) to 3 x 10(10) M(-1) and are dependent on both the nature of the end group as well as the length and hydrophobicity of the central linker. The magnitude of the stability constants for the 2:1 complexes closely follow the trend observed previously for CB[7] binding with the NR(4)(+) and PR(4)(+) cations.

  13. Macrocyclic cavitands cucurbit[n]urils: prospects for application in biochemistry, medicine and nanotechnology

    Science.gov (United States)

    Gerasko, O. A.; Kovalenko, E. A.; Fedin, V. P.

    2016-08-01

    The prospects of using the organic macrocyclic cavitands cucurbit[n]urils (CB[n]) and their derivatives in biochemistry, medicine and nanotechnology are considered. A combination of CB[n] characteristics, such as a rigid highly symmetrical structure, polarized hydrophilic portals, a rather large intramolecular hydrophobic cavity, as well as high resistance to thermolysis and corrosive media and low toxicity, account for a wide range of unique opportunities for the deliberate design of new functional materials, which may find application in various areas of modern chemistry and new technologies. Inclusion compounds of CB[n] with biologically active molecules demonstrate a high potential for the design of a new generation of prolonged action pharmaceuticals. The review presents the prospects for the application of CB[n] to manufacture unique materials, such as CB[n]-containing vesicles, films and surfaces, suitable for immobilization of various molecules and nanoparticles on their surface and for the separation of complex mixtures. Potential applications of CB[n]-modified electrodes and hydrogels are analyzed, and the use of CB[n] in proton-conducting materials and materials for the gas sorption and separation are discussed. The bibliography includes 164 references.

  14. Spectroscopy and Dynamics of Cryptolepine in the Nanocavity of Cucurbit[7]uril and DNA.

    Science.gov (United States)

    Koninti, Raj Kumar; Sappati, Subrahmanyam; Satpathi, Sagar; Gavvala, Krishna; Hazra, Partha

    2016-02-16

    Herein, we explored the photophysical properties of the antimalarial, anticancer drug cryptolepine (CRYP) in the presence of the macrocyclic host cucurbit[7]uril (CB7) and DNA with the help of steady-state and time-resolved fluorescence techniques. Ground-state and excited-state calculations based on density functional theory were also performed to obtain insight into the shape, electron density distribution, and energetics of the molecular orbitals of CRYP. CRYP exists in two forms depending on the pH of the medium, namely, a cationic (charge transfer) form and a neutral form, which emit at λ=540 and 420 nm, respectively. In a buffer solution of pH 7, the drug exists in the cationic form, and upon encapsulation with CB7, it exhibits a huge enhancement in fluorescence intensity due to a decrement in nonradiative decay pathways of the emitting cryptolepine species. Furthermore, docking and quantum chemical calculations were employed to decipher the molecular orientation of the drug in the inclusion complex. Studies with natural DNA indicate that CRYP molecules intercalate into DNA, which leads to a huge quenching of the fluorescence of CRYP. Keeping this in mind, we studied the DNA-assisted release of CRYP molecules from the nanocavity of CB7. Strikingly, DNA alone could not remove the drug from the nanocavity of CB7. However, an external stimulus such as acetylcholine chloride was able to displace CRYP from the nanocavity, and subsequently, the displaced drug could bind to DNA.

  15. Complexation of Eu(III) with cucurbit[n]uril, n = 5 and 7: a thermodynamic and structural study.

    Science.gov (United States)

    Rawat, Neetika; Kar, Aishwarya; Bhattacharyya, A; Rao, Ankita; Nayak, S K; Nayak, C; Jha, S N; Bhattacharyya, D; Tomar, B S

    2015-03-07

    Cucurbit[n]urils (CBn) are a new class of macrocyclic cage compounds capable of binding organic and inorganic species, owing to their unique pumpkin like structure comprising of both a hydrophobic cavity and a hydrophilic portal. The thermodynamics of the complexation of Eu(III) with CBn of a different cavity size viz. cucurbit[5]uril (CB5) and cucurbit[7]uril (CB7) has been studied by UV-Vis spectroscopy and calorimetry at 25 °C whereas the structure of the complexes was investigated using time resolved fluorescence spectroscopy (TRFS) and extended X-ray absorption fine structure spectroscopy (EXAFS) in a formic acid-water mixture (50 wt%). This is the first report on the structural investigation of Eu-CBn complexes in solution. The thermodynamic data (ΔG, ΔH and ΔS) for Eu(III) complexation with CBn reveal the formation of a 1 : 1 complex with CB5, while both 1 : 1 and 1 : 2 complexes are observed with CB7. The signatures of these species are observed in ESI-MS measurements, which corroborates with the species postulated in thermodynamic studies. The complexation reactions are found to be driven by ΔS as ΔH is either small negative or positive indicating the formation of inner sphere complexes, which is in line with TRFS and EXAFS results. These studies show that Eu(III) caps one of the CB5 portals by binding with all the carbonyl groups in the 1 : 1 Eu-CB5 complex, whereas in the 1 : 1 Eu-CB7 complex, Eu(III) interacts with only a few of the carbonyl groups of CB7. The computational studies (DFT calculations) on Eu-CB5 and Eu-CB7 complexes further support the experimental data.

  16. In vivo detection of cucurbit[6]uril, a hyperpolarized xenon contrast agent for a xenon magnetic resonance imaging biosensor

    Science.gov (United States)

    Hane, Francis T.; Li, Tao; Smylie, Peter; Pellizzari, Raiili M.; Plata, Jennifer A.; DeBoef, Brenton; Albert, Mitchell S.

    2017-01-01

    The Hyperpolarized gas Chemical Exchange Saturation Transfer (HyperCEST) Magnetic Resonance (MR) technique has the potential to increase the sensitivity of a hyperpolarized xenon-129 MRI contrast agent. Signal enhancement is accomplished by selectively depolarizing the xenon within a cage molecule which, upon exchange, reduces the signal in the dissolved phase pool. Herein we demonstrate the in vivo detection of the cucurbit[6]uril (CB6) contrast agent within the vasculature of a living rat. Our work may be used as a stepping stone towards using the HyperCEST technique as a molecular imaging modality. PMID:28106110

  17. Decorating in situ ultrasmall tin particles on crumpled N-doped graphene for lithium-ion batteries with a long life cycle

    Science.gov (United States)

    Liu, Lianjun; Huang, Xingkang; Guo, Xiaoru; Mao, Shun; Chen, Junhong

    2016-10-01

    The practical application of Sn, a promising anode material for lithium-ion batteries, is hindered primarily by its huge volume change (up to 260%) upon lithiation. To tackle this obstacle, here we report a facile one-pot method, i.e., pyrolysis of a mixture of GO, SnCl4, and cyanamide at elevated temperatures to create in situ a novel mesoporous structure of Sn@N-doped graphene (Sn@NG). In the constructed architecture, the ultrasmall Sn nanoparticles (2-3 nm) are uniformly embedded in the NG network while the crumpled NG provides good electronic conductivity, abundant defects, high surface area, and large mesopore volume. Due to the combination of these merits, Sn@NG exhibits extremely long-term cycling stability, even at high rates, retaining a capacity of 568 mAh g-1 at 1 A g-1 (90% retention) and 535 mAh g-1 at 2 A g-1 (91.6% retention) after 1000 and 900 cycles, respectively. This performance is superior to that of Sn@G (without N-doping) and Sn//NG prepared using a two-step process with large particle sizes (>30 nm) and uneven dispersion of Sn. The findings from this work will shed light on the design of efficient and stable Sn and other metal-based materials for energy storage and conversion.

  18. A facile approach to prepare crumpled CoTMPyP/electrochemically reduced graphene oxide nanohybrid as an efficient electrocatalyst for hydrogen evolution reaction

    Science.gov (United States)

    Ma, Juanjuan; Liu, Lin; Chen, Qian; Yang, Min; Wang, Danping; Tong, Zhiwei; Chen, Zhong

    2017-03-01

    Elaborate design and synthesis of efficient and stable non-Pt electrocatalysts for some renewable energy related conversion/storage processes are one of the major goals of sustainable chemistry. Herein, we report a facile method to fabricate Co porphyrin functionalized electrochemically reduced graphene oxide (CoTMPyP/ERGO) thin film by direct assembly of oppositely charged tetrakis(N-methylpyridyl) porphyrinato cobalt (CoTMPyP) and GO nanosheets under mild conditions followed by an electrochemical reduction procedure. STEM analysis confirms that CoTMPyP nanoaggregates are homogeneously distributed over the graphene surface. The electrochemical properties of CoTMPyP/ERGO were investigated by cyclic voltammetry, linear sweep voltammetry and electrochemical impedance spectroscopy. The results demonstrate that CoTMPyP/ERGO nanohybrid film can serve as excellent electrocatalyst for hydrogen evolution in alkaline solution with high activity and stability. The intimate contact and efficient electron transfer between CoTMPyP and ERGO, as well as the crumpled structure, contribute to the improvement of the electrocatalytic performance.

  19. SYNTHESIS AND PROPERTIES OF COPOLYMERS CONTAINING CUCURBIT[6]URIL-BASED PSEUDOROTAXANE STRUCTURE

    Institute of Scientific and Technical Information of China (English)

    Qiang Ma; Hui Yang; Kimoon Kim; Ye-bang Tan

    2012-01-01

    Novel copolymers based on acrylamide (AM) and complex pseudorotaxane monomer N'-(3-vinylbenzyl)-l,4-diaminobutane dihydrochloride with cucurbit[6]uril (CB[6]) (3VBCB) were prepared via free-radical polymerization in aqueous solution,and characterized by 1H-NMR,FT-IR,elemental analysis and static light scattering.The compositions of the copolymers (PAM3VBCB) with pseudorotaxane units were determined by 1H-NMR and elemental analysis.Thermal properties of the copolymers were studied by TGA,and the effects of the copolymer concentration and pH on the average hydrodynamic radius (Rh) of the copolymer molecules were studied by dynamic light scattering (DLS).The experiment data show that CB[6] beads are localized on 1,4-diaminobutane units in side chains of the copolymers.TGA results show that thermal stability of the copolymer increases with increasing the content of pseudorotaxane unit because of the enhanced rigidity and the bulky steric hindrance of 3VBCB in side chains of PAM3VBCB.DLS data show that the average hydrodynamic radius of copolymer molecules increases with the increase in the copolymer concentration,and both the pH and electrical conductivity of PAM3VBCB solutions demonstrate an acute change with addition of NaOH because of CB[6]dethreading from the side chains of PAM3VBCB.CB[6] threading and dethreading of PAM3VBCB could be controlled by addition of BaCl2 and Na2SO4.

  20. Genetic and virulence variability among Erwinia tracheiphila strains recovered from different cucurbit hosts.

    Science.gov (United States)

    Rojas, E Saalau; Dixon, P M; Batzer, J C; Gleason, M L

    2013-09-01

    The causal agent of cucurbit bacterial wilt, Erwinia tracheiphila, has a wide host range in the family Cucurbitaceae, including economically important crops such as muskmelon (Cucumis melo), cucumber (C. sativus), and squash (Cucurbita spp.). Genetic variability of 69 E. tracheiphila strains was investigated by repetitive-element polymerase chain reaction (rep-PCR) using BOXA1R and ERIC1-2 primers. Fingerprint profiles revealed significant variability associated with crop host; strains isolated from Cucumis spp. were clearly distinguishable from Cucurbita spp.-isolated strains regardless of geographic origin. Twelve E. tracheiphila strains isolated from muskmelon, cucumber, or summer squash were inoculated onto muskmelon and summer squash seedlings, followed by incubation in a growth chamber. Wilt symptoms were assessed over 3 weeks, strains were reisolated, and rep-PCR profiles were compared with the inoculated strains. Wilting occurred significantly faster when seedlings were inoculated with strains that originated from the same crop host genus (P<0.001). In the first run of the experiment, cucumber and muskmelon strains caused wilting on muskmelon seedlings at a median of 7.8 and 5.6 days after inoculation (dai), respectively. Summer squash seedlings wilted 18.0, 15.7, and 5.7 dai when inoculated with muskmelon-, cucumber-, and squash-origin strains, respectively. In a second run of the experiment, cucumber and muskmelon strains caused wilting on muskmelon at 7.0 and 6.9 dai, respectively, whereas summer squash seedlings wilted at 23.6, 29.0 and 9.0 dai when inoculated with muskmelon-, cucumber-, and squash-origin strains, respectively. Our results provide the first evidence of genetic diversity within E. tracheiphila and suggest that strain specificity is associated with plant host. This advance is a first step toward understanding the genetic and population structure of E. tracheiphila.

  1. U-shaped conformation of alkyl chains bound to a synthetic receptor cucurbit[8]uril.

    Science.gov (United States)

    Ko, Young Ho; Kim, Youngkook; Kim, Hyunuk; Kim, Kimoon

    2011-02-01

    The behavior of a series of alkanes bound to the molecular host cucurbit[8]uril (CB[8]) has been systematically studied by 2D (1)H NMR spectroscopy and isothermal titration calorimetry (ITC). CB[8] and alkyltrimethylammonium (C(m) TA(+), (CH(3))(3)N(+)C(m)H(2m+1), m=6-16) form 1:1 host-guest complexes with a high binding constant (K≈10(6) m(-1)). The shortest hexyl chain of C(6)TA(+) can be fully encapsulated in an extended conformation inside the CB[8] cavity, which is driven by both enthalpy and entropy. However, for the longer aliphatic chains, C(8)-C(16), the long alkyl tails take a U-shaped conformation inside the cavity, and their complexation is dominantly or almost exclusively enthalpy-driven, owing to the increased van der Waals contact between the folded aliphatic chain and the inner wall of the host cavity. As the chain length increases from C(8) to C(16), the ammonium head group of the guests moves away from the portal of CB[8] while the long aliphatic tails maintain the U-shaped conformation inside the cavity. The complexation of C(m)TA(+) with CB[8] follows the enthalpy-entropy compensation rule commonly observed in molecular recognition systems. For example, among the guest molecules, C(12)TA(+) shows the highest enthalpic gain (most favorable), owing to the large van der Waals contact between the guest and the host cavity, and at the same time the most unfavorable entropic contribution, owing to the severe conformational restriction of the U-shaped alkyl chain inside the host. The enthalpy-entropy compensation plot for the complexation suggests large conformational changes of the long alkyl chains and extensive dehydration associated with the inclusion complex formation.

  2. Examination of cucurbit[7]uril and its host-guest complexes by diffusion nuclear magnetic resonance.

    Science.gov (United States)

    Wheate, Nial J; Kumar, P G Anil; Torres, Allan M; Aldrich-Wright, Janice R; Price, William S

    2008-02-28

    The self-diffusion of cucurbit[7]uril (CB[7]) and its host-guest complexes in D2O has been examined using pulsed gradient spin-echo nuclear magnetic resonance spectroscopy. CB[7] diffuses freely at a concentration of 2 mM with a diffusion coefficient (D) of 3.07 x 10(-10) m(2) s(-1). At saturation (3.7 mM), CB[7] diffuses more slowly (D = 2.82 x 10(-10) m(2) s(-1)) indicating that it partially self-associates. At concentrations between 2 and 200 mM, CsCl has no effect on the diffusion coefficient of CB[7] (1 mM). Conversely, CB[7] (2 mM) significantly affects the diffusion of 133Cs+ (1 mM), decreasing its diffusion coefficient from 1.86 to 0.83 x 10(-9) m(2) s(-1). Similar changes in the rate of diffusion of other alkali earth metal cations are observed upon the addition of CB[7]. The diffusion coefficient of 23Na+ changes from 1.26 to 0.90 x 10(-9) m(2) s(-1) and 7Li+ changes from 3.40 to 3.07 x 10(-9) m(2) s(-1). In most cases, encapsulation of a variety of inorganic and organic guests within CB[7] decreases their rates of diffusion in D2O. For instance, the diffusion coefficient of the dinuclear platinum complex trans-[[PtCl(NH3)2}2mu-dpzm](2+) (where dpzm is 4,4'-dipyrazolylmethane) decreases from 4.88 to 2.95 x 10(-10) m(2) s(-1) upon encapsulation with an equimolar concentration of CB[7].

  3. Selección de rizobacterias por su antagonismo frente a microorganismos patógenos de cucurbitáceas /Screening of rhizobacteria for their antagonism against microbial pathogens of cucurbits.

    Directory of Open Access Journals (Sweden)

    Gilda Jiménez Montejo

    2014-04-01

    Full Text Available Resumen:El desarrollo de inoculantes microbianos a partir de aislamientos de rizobacterias con potencial para el control biológico de enfermedades de los cultivos agrícolas requiere de una rigurosa selección. Se obtuvieron aislamientos bacterianos de la rizosfera de papa (Solanum tuberosum L. y de maíz (Zea mays L. y de semillas de frijol (Phaseolus vulgaris L.. Las colonias que mostraron in vitro halos de inhibición de los patógenos de cucurbitáceas: Xanthomonas cucurbitae, Acidovorax avenae subsp. citrull y Fusarium oxysporum, se seleccionaron como antagonistas. A partir de las características morfológicas, fisiológicas y bioquímicas las cepas antagonistas F16/95 y Xph se identificaron con la especie Bacillus subtilis y la cepa 14A como Pseudomonas putida. Las pruebas presuntivas de producción de antibiocinas in vitro sugirieron modos de acción de las rizobacterias relacionados con antibiosis y competencia por el hierro mediante la producción de sideróforos. Los resultados indicaron el potencial de las cepas de rizobacterias antagonistas Bacillus subtilis (F16/95, Xph y Pesudomonas putida 14A para el control biológico de enfermedades de las cucurbitáceas./Abstract:

  4. Characterization of endophytic bacteria from cucurbit fruits with potential benefits to agriculture in melons (Cucumis melo L.).

    Science.gov (United States)

    Glassner, Hanoch; Zchori-Fein, Einat; Compant, Stéphane; Sessitsch, Angela; Katzir, Nurit; Portnoy, Vitaly; Yaron, Sima

    2015-07-01

    Endophytes are microorganisms that mainly colonize vegetative parts, but are also found in reproductive and disseminating organs, and may have beneficial characteristics. To identify microorganisms associated with the agriculturally important family, Cucurbitaceae, endophytes were initially determined in fruits of Cucumis melo Reticulatus Group 'Dulce' by a cultivation-independent approach based on fluorescence in situ hybridization using double labeling of oligonucleotide probes. Alpha-, Beta-, Gammaproteobacteria, Firmicutes and Actinobacteria were localized inside the fruits. Culturable bacteria were further isolated and identified from fruit tissues of 'Dulce', from fruits of other cultivated and wild-field-grown Cucurbitaceae, and from wild fruits growing under natural conditions. Low densities of culturable bacteria were detected in the investigated fruits, especially in four out of the five wild species, regardless of their growing environment. Substantial differences were observed between the wild and cultivated cucurbit taxa in regard to the number of colonized fruits as well as the type of endophytes. Bacillus was the most dominant genus of endophytes colonizing fruits of Cucurbitaceae. The antagonistic effects of isolated endophytes were assessed against cucurbit disease agents in dual-culture assays. Several bacterial isolates exhibited antagonistic properties against the tested plant pathogens. The identified bacteria may be useful for protecting plants not only in the field, but also for post-harvest.

  5. Aniline-containing guests recognized by α,α’,δ,δ’-tetramethyl-cucurbit[6]uril host

    Science.gov (United States)

    Lin, Rui-Lian; Fang, Guo-Sheng; Sun, Wen-Qi; Liu, Jing-Xin

    2016-12-01

    The host-guest complexation of symmetrical α,α’,δ,δ’-tetramethyl-cucurbit[6]uril (TMeQ[6]) and cucurbit[7]uril (Q[7]) with a series of aniline-containing guests has been investigated by various experimental techniques including NMR, ITC, and X-ray crystallography. Experimental results indicate that both TMeQ[6] and Q[7] hosts can encapsulate aniline-containing guests to form stable inclusion complexes. However, the oval cavity of TMeQ[6] is more complementary in size and shape to the aromatic ring of the guests than the spherical cavity of Q[7]. Shielding and deshielding effects of the aromatic ring on guests lead to the remarkable chemical shifts of the TMeQ[6] host protons. The rotational restriction of the guests in the oval cavity of TMeQ[6] results in the large negative values of entropy. The X-ray crystal structure of the 1:1 inclusion complex between TMeQ[6] and N,N‧-diethyl-benzene-1,4-diamine unambiguously reveals that the aromatic ring of the guest resides in the oval cavity of TMeQ[6].

  6. Monitoring and Varietal Screening Cucurbit Fruit Fly, Bactrocera cucurbitae Coquillett (Diptera: Tephritidae on Cucumber in Bhaktapur and Kathmandu, Nepal

    Directory of Open Access Journals (Sweden)

    Ranju Maharjan

    2015-12-01

    Full Text Available Monitoring of cucurbit fruit fly by using four different types of traps was conducted in Sipadole VDC of Bhaktapur district during 2012 to observe the population dynamics. Three different types of fruit flies were recorded, in which the number of B. cucurbitae dominated to other species. Only B. cucurbitae damaged the cucumber, which was trapped 92.68%, 87.05%, 90.61%, and 69.38% in cue-lure, banana pulp bait, sticky traps and fly catcher, respectively. The highest number of fruit flies (167.5 male fruit flies/3traps was recorded in cue-lure trap during the first week of September, which coincided with 85.45% RH and 21.67°C and 25.04°C minimum and maximum temperature, respectively. Positive relation of temperature, relative humidity and fruit fly catches was observed. Thus, cue-lure was the most effective traps for monitoring of fruit fly population. In varietal screening, among the six different varieties of cucumber, i.e. Kathmandu local, Kusle, Kamini, Malini, Kasinda and Mahyco Green Long, they were highly significant difference in yield. Kamini gave the highest marketable fruit 26.66 mt/ha yield and the lowest by Kusle (5.05 mt/ha. All the varieties were affected by cucurbit fruit fly. The highest number of unmarketable fruit set was observed in Kamini (22.29 fruits/plant.

  7. Systemic induction of NO-, redox- and cGMP signalling in the pumpkin extrafascicular phloem upon local leaf wounding

    Directory of Open Access Journals (Sweden)

    Frank eGaupels

    2016-02-01

    Full Text Available Cucurbits developed the unique extrafascicular phloem (EFP as a defensive structure against herbivorous animals. Mechanical leaf injury was previously shown to induce a systemic wound response in the EFP of pumpkin (Cucurbita maxima. Here, we demonstrate that the phloem antioxidant system and protein modifications by NO are strongly regulated during this process. Activities of the central antioxidant enzymes dehydroascorbate reductase, glutathione reductase and ascorbate reductase were rapidly down-regulated at 30 min with a second minimum at 24 h after wounding. As a consequence levels of total ascorbate and glutathione also decreased with similar bi-phasic kinetics. These results hint towards a wound-induced shift in the redox status of the EFP. Nitric oxide (NO is another important player in stress-induced redox signalling in plants. Therefore, we analysed NO-dependent protein modifications in the EFP. Six to 48 h after leaf damage total S-nitrosothiol content and protein S-nitrosylation were clearly reduced, which was contrasted by a pronounced increase in protein tyrosine nitration. Collectively, these findings suggest that NO-dependent S-nitrosylation turned into peroxynitrite-mediated protein nitration upon a stress-induced redox shift probably involving the accumulation of reactive oxygen species within the EFP. Using the biotin switch assay and anti-nitrotyrosine antibodies we identified 9 candidate S-nitrosylated and 6 candidate tyrosine-nitrated phloem proteins. The wound-responsive Phloem Protein 16-1 (PP16-1 and Cyclophilin 18 (CYP18 as well as the 26.5 kD isoform of Phloem Protein 2 (PP2 were amenable to both NO modifications and could represent important redox-sensors within the cucurbit EFP. We also found that leaf injury triggered the systemic accumulation of cyclic guanosine monophosphate (cGMP in the EFP and discuss the possible function of this second messenger in systemic NO and redox signalling within the EFP.

  8. Modeling leaf venation morphogenesis

    CERN Document Server

    Laguna, M F; Jagla, E A

    2007-01-01

    We explore the possibility that the formation of leaf venation patterns is driven by mechanical instabilities in the growing leaf. In contrast to the prevalent canalization hypothesis based on polar auxin transport, mechanical instabilities lead very naturally to hierarchical patterns with an abundant number of closed loops as they exists in almost every leaf venation. We propose a continuum model where the vein formation is driven by a mechanical collapse of the mesophyll layer in the growing leaf, and present a numerical study of this model using a phase field approach. The results show the same qualitative features as real venation patterns and, furthermore, have the same statistical properties.

  9. Grid inhomogeneous solvation theory: hydration structure and thermodynamics of the miniature receptor cucurbit[7]uril.

    Science.gov (United States)

    Nguyen, Crystal N; Young, Tom Kurtzman; Gilson, Michael K

    2012-07-28

    The displacement of perturbed water upon binding is believed to play a critical role in the thermodynamics of biomolecular recognition, but it is nontrivial to unambiguously define and answer questions about this process. We address this issue by introducing grid inhomogeneous solvation theory (GIST), which discretizes the equations of inhomogeneous solvation theory (IST) onto a three-dimensional grid situated in the region of interest around a solute molecule or complex. Snapshots from explicit solvent simulations are used to estimate localized solvation entropies, energies, and free energies associated with the grid boxes, or voxels, and properly summing these thermodynamic quantities over voxels yields information about hydration thermodynamics. GIST thus provides a smoothly varying representation of water properties as a function of position, rather than focusing on hydration sites where solvent is present at high density. It therefore accounts for full or partial displacement of water from sites that are highly occupied by water, as well as for partly occupied and water-depleted regions around the solute. GIST can also provide a well-defined estimate of the solvation free energy and therefore enables a rigorous end-states analysis of binding. For example, one may not only use a first GIST calculation to project the thermodynamic consequences of displacing water from the surface of a receptor by a ligand, but also account, in a second GIST calculation, for the thermodynamics of subsequent solvent reorganization around the bound complex. In the present study, a first GIST analysis of the molecular host cucurbit[7]uril is found to yield a rich picture of hydration structure and thermodynamics in and around this miniature receptor. One of the most striking results is the observation of a toroidal region of high water density at the center of the host's nonpolar cavity. Despite its high density, the water in this toroidal region is disfavored energetically and

  10. Leaf Size in Swietenia

    Science.gov (United States)

    Charles B. Briscoe; F. Bruce. Lamb

    1962-01-01

    A study was made of the putative hybrid of bigleaf and small-leaf mahoganies. Initial measurements indicated that bigleaf mahogany can be distinguished from small-leaf mahogany by gross measurements of leaflets. Isolated mother trees yield typical progeny. Typical mother trees in mixed stands yield like progeny plus, usually, mediumleaf progeny. Mediumleaf mother trees...

  11. A highly luminescent tetramer from a weakly emitting monomer: acid- and redox-controlled multiple complexation by cucurbit[7]uril.

    Science.gov (United States)

    Bergamini, Giacomo; Fermi, Andrea; Marchini, Marianna; Locritani, Mirko; Credi, Alberto; Venturi, Margherita; Negri, Fabrizia; Ceroni, Paola; Baroncini, Massimo

    2014-06-01

    The tetrahedral, shape-persistent molecule 1(4+), containing four pyridylpyridinium units connected through a central carbon atom, exhibits unexpected photophysical properties including a substantially redshifted absorption (2350 cm(-1)) and a very strong fluorescence (Φem = 40 %), compared with the monomer 2(+) (Φem = 0.4 %). Density functional theory calculations on the structure and spectroscopic properties of 1(4+) and 2(+) show that exciton interactions, homoconjugation, and orbital nature account for the observed differences in their photophysical properties. The protonated tetramer binds four cucurbit[7]uril molecules and the host/guest interactions can be controlled by chemical (acid/base) as well as redox stimuli.

  12. Emission of hydrogen sulfide by leaf tissue in response to L-cysteine

    Energy Technology Data Exchange (ETDEWEB)

    Sekiya, J.; Schmidt, A.; Wilson, L.G.; Filner, P.

    1982-08-01

    Leaf discs and detached leaves exposed to L-cysteine emitted a volatile sulfur compound which was proven by gas chromatography to be H/sub 2/S. This phenomenon was demonstrated in all nine species tested (Cucumis sativus, Cucurbita pepo, Nicotiana tabacum, Coleus blumei, Beta vulgaris, Phaseolus vulgaris, Medicago sativa, Hordeum vulgare, and Gossypium hirsutum). The emission of volatile sulfur by cucumber leaves occurred in the dark at a similar rate to that in the light. The emission of leaf discs reached the maximal rate, more than 40 picomoles per minute per square centimeter, 2 to 4 hours after starting exposure to L-cysteine; then it decreased. In the case of detached leaves, the maximum occurred 5 to 10 h after starting exposure. The average emission rate of H/sub 2/S during the first 4 hours from leaf discs of cucurbits in response to 10 millimolar L-cysteine, was usually more than 40 picomoles per minute per square centimeter, i.e. 0.24 micromoles per hour per square decimeter. Leaf discs exposed to 1 millimolar L-cysteine emitted only 2% as much as did the discs exposed to 10 millimolar L-cysteine. The emission from leaf discs and from detached leaves lasted for at least 5 and 15 hours, respectively. However, several hours after the maximal emission, injury of the leaves, manifested as chlorosis, was evident. H/sub 2/S emission was a specific consequence of exposure to L-cysteine; neither D-cysteine nor L-cysteine elicited H/sub 2/S emission. Aminooxyacetic acid, an inhibitor of pyridoxal phosphate dependent enzymes, inhibited the emission. In a cell free system from cucumber leaves, H/sub 2/S formation and its release occurred in response to L-cysteine. Feeding experiments with (/sup 35/S)t-cysteine showed that most of the sulfur in H/sub 2/S was derived from sulfur in the L-cysteine supplied.

  13. Patterns of species richness and diversity of insects associated with cucurbit fruits in the southern part of Cameroon.

    Science.gov (United States)

    Mokam, Didi Gaëlle; Djiéto-Lordon, Champlain; Bilong Bilong, Charles-Félix

    2014-01-01

    Patterns of species diversity and community structure of insects associated with fruits of domesticated cucurbits were investigated from January 2009 to 2011 in three localities from two agroecological zones in the southern part of Cameroon. Rarefaction curves combined with nonparametric estimators of species richness were used to extrapolate species richness beyond our own data. Sampling efforts of over 92% were reached in each of the three study localities. Data collected revealed a total of 66 insect morphospecies belonging to 37 families and five orders, identified from a set of 57,510 insects. The orders Diptera (especially Tephritidae and Lonchaeidae) and Hymenoptera (mainly Braconidae and Eulophidae) were the most important, in terms of both abundance and species richness on the one hand, and effects on agronomic performance on the other. Values for both the species diversity (Shannon and Simpson) and the species richness indices (Margalef and Berger-Parker) calculated showed that the insect communities were species-rich but dominated, all to a similar extent, by five main species (including four fruit fly species and one parasitoid). Species abundance distributions in these communities ranged from the Zipf-Mandelbrot to Mandelbrot models. The communities are structured as tritrophic networks, including cucurbit fruits, fruit-feeding species (fruit flies) and carnivorous species (parasitoids). Within the guild of the parasitoids, about 30% of species, despite their low abundance, may potentially be of use in biological control of important pests. Our field data contribute in important ways to basic knowledge of biodiversity patterns in agrosystems and constitute baseline data for the planned implementation of biological control in Integrated Pest Management. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

  14. Leaf growth is conformal

    CERN Document Server

    Alim, Karen; Shraiman, Boris I; Boudaoud, Arezki

    2016-01-01

    Growth pattern dynamics lie at the heart of morphogenesis. Here, we investigate the growth of plant leaves. We compute the conformal transformation that maps the contour of a leaf at a given stage onto the contour of the same leaf at a later stage. Based on the mapping we predict the local displacement field in the leaf blade and find it to agree with the experimentally measured displacement field to 92%. This approach is applicable to any two-dimensional system with locally isotropic growth, enabling the deduction of the whole growth field just from observation of the tissue contour.

  15. Leaf growth is conformal

    Science.gov (United States)

    Alim, Karen; Armon, Shahaf; Shraiman, Boris I.; Boudaoud, Arezki

    2016-10-01

    Growth pattern dynamics lie at the heart of morphogenesis. Here, we investigate the growth of plant leaves. We compute the conformal transformation that maps the contour of a leaf at a given stage onto the contour of the same leaf at a later stage. Based on the mapping we predict the local displacement field in the leaf blade and find it to agree with the experimentally measured displacement field to 92%. This approach is applicable to any two-dimensional system with locally isotropic growth, enabling the deduction of the whole growth field just from observation of the tissue contour.

  16. In Vitro Synthesized RNA Generated from cDNA Clones of Both Genomic Components of Cucurbit yellow stunting disorder virus Replicates in Cucumber Protoplasts

    Science.gov (United States)

    Owen, Carolyn A.; Moukarzel, Romy; Huang, Xiao; Kassem, Mona A.; Eliasco, Eleonora; Aranda, Miguel A.; Coutts, Robert H. A.; Livieratos, Ioannis C.

    2016-01-01

    Cucurbit yellow stunting disorder virus (CYSDV), a bipartite whitefly-transmitted virus, constitutes a major threat to commercial cucurbit production worldwide. Here, construction of full-length CYSDV RNA1 and RNA2 cDNA clones allowed the in vitro synthesis of RNA transcripts able to replicate in cucumber protoplasts. CYSDV RNA1 proved competent for replication; transcription of both polarities of the genomic RNA was detectable 24 h post inoculation. Hybridization of total RNA extracted from transfected protoplasts or from naturally CYSDV-infected cucurbits revealed high-level transcription of the p22 subgenomic RNA species. Replication of CYSDV RNA2 following co-transfection with RNA1 was also observed, with similar transcription kinetics. A CYSDV RNA2 cDNA clone (T3CM8Δ) comprising the 5′- and 3′-UTRs plus the 3′-terminal gene, generated a 2.8 kb RNA able to replicate to high levels in protoplasts in the presence of CYSDV RNA1. The clone T3CM8Δ will facilitate reverse genetics studies of CYSDV gene function and RNA replication determinants. PMID:27314380

  17. In Vitro Synthesized RNA Generated from cDNA Clones of Both Genomic Components of Cucurbit yellow stunting disorder virus Replicates in Cucumber Protoplasts

    Directory of Open Access Journals (Sweden)

    Carolyn A. Owen

    2016-06-01

    Full Text Available Cucurbit yellow stunting disorder virus (CYSDV, a bipartite whitefly-transmitted virus, constitutes a major threat to commercial cucurbit production worldwide. Here, construction of full-length CYSDV RNA1 and RNA2 cDNA clones allowed the in vitro synthesis of RNA transcripts able to replicate in cucumber protoplasts. CYSDV RNA1 proved competent for replication; transcription of both polarities of the genomic RNA was detectable 24 h post inoculation. Hybridization of total RNA extracted from transfected protoplasts or from naturally CYSDV-infected cucurbits revealed high-level transcription of the p22 subgenomic RNA species. Replication of CYSDV RNA2 following co-transfection with RNA1 was also observed, with similar transcription kinetics. A CYSDV RNA2 cDNA clone (T3CM8Δ comprising the 5′- and 3′-UTRs plus the 3′-terminal gene, generated a 2.8 kb RNA able to replicate to high levels in protoplasts in the presence of CYSDV RNA1. The clone T3CM8Δ will facilitate reverse genetics studies of CYSDV gene function and RNA replication determinants.

  18. In Vitro Synthesized RNA Generated from cDNA Clones of Both Genomic Components of Cucurbit yellow stunting disorder virus Replicates in Cucumber Protoplasts.

    Science.gov (United States)

    Owen, Carolyn A; Moukarzel, Romy; Huang, Xiao; Kassem, Mona A; Eliasco, Eleonora; Aranda, Miguel A; Coutts, Robert H A; Livieratos, Ioannis C

    2016-06-14

    Cucurbit yellow stunting disorder virus (CYSDV), a bipartite whitefly-transmitted virus, constitutes a major threat to commercial cucurbit production worldwide. Here, construction of full-length CYSDV RNA1 and RNA2 cDNA clones allowed the in vitro synthesis of RNA transcripts able to replicate in cucumber protoplasts. CYSDV RNA1 proved competent for replication; transcription of both polarities of the genomic RNA was detectable 24 h post inoculation. Hybridization of total RNA extracted from transfected protoplasts or from naturally CYSDV-infected cucurbits revealed high-level transcription of the p22 subgenomic RNA species. Replication of CYSDV RNA2 following co-transfection with RNA1 was also observed, with similar transcription kinetics. A CYSDV RNA2 cDNA clone (T3CM8Δ) comprising the 5'- and 3'-UTRs plus the 3'-terminal gene, generated a 2.8 kb RNA able to replicate to high levels in protoplasts in the presence of CYSDV RNA1. The clone T3CM8Δ will facilitate reverse genetics studies of CYSDV gene function and RNA replication determinants.

  19. Separation performance of cucurbit[8]uril and its coordination complex with cadmium (II) in capillary gas chromatography.

    Science.gov (United States)

    Sun, Tao; Ji, Ningning; Qi, Meiling; Tao, Zhu; Fu, Ruonong

    2014-05-23

    Here we report the investigation of using cucurbit[8]uril (CB8) and its coordination complex with cadmium (II) (CB8-Cd) as stationary phases for capillary gas chromatography (GC). The prepared capillary columns of CB8 and CB8-Cd stationary phases achieved column efficiency of 2200plates/m and 1508plates/m, respectively, and showed weak polarity based on the measured McReynolds constants. Their separation performance was investigated by GC separation of mixtures of different types while a commercial column was used for comparison. The CB8 stationary phase achieved high resolution for a wide range of analytes from nonpolar to polar while the CB8-Cd stationary phase exhibited good separation mainly for nonpolar to weak polar analytes. The CB stationary phases differ from the commercial one in terms of retention behaviors and resolving ability due to their different molecular interactions with analytes. Moreover, energy effect on the retention of analytes on CB8 and CB8-Cd stationary phases was examined, showing that retention on CB8 column was determined mainly by enthalpy change for polar analytes and by both enthalpy change and entropy change for weak polar analytes whereas retention on CB8-Cd column was mainly controlled by entropy change. This work demonstrates the great potential of CB8 and CB8-Cd stationary phases as a new type of GC stationary phases in GC analysis.

  20. Preparation and characterization of inclusion complexes of antitumor camptothecin with cucurbit[n=7,8]urils

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The slightly water-soluble anticancer drug camptothecin(CPT) and its inclusion complexes with cucurbit[n = 7,8]uril(Q[n](n = 7,8)) were investigated.The formation of 1:2 complexes with Q[n](n = 7,8) in aqueous solution was confirmed by fluorescence spectroscopy and the apparent stability constants were determined to be higher than 3.01 × 1012 L2/mol2.The solid inclusion complexes of CPT and Q[n](n = 7,8) were also prepared by the co-evaporation method and characterized by Fourier transformation-infrared spectroscopy,differential scanning calorimetry and powder X-ray diffraction.Aqueous solubility and dissolution studies indicate that the complexes exhibited significantly increased dissolution rates compared with the pure drug and physical mixtures.The potential of Q[7] or Q[8] for stabilizing lactone modality of CPT was investigated by the High Performance Liquid Chromatography(HPLC) method.The results reveal more than 63% CPT lactone form(active form) in CPT-Q[7] or Q[8] complexes compared to only 36% CPT lactone form in the absence of Q[7] or Q[8] after being incubated in the phosphate buffer solution(pH 7.4 at 37 °C) for 5h.

  1. A Binary Bivalent Supramolecular Assembly Platform Based on Cucurbit[8]uril and Dimeric Adapter Protein 14-3-3.

    Science.gov (United States)

    de Vink, Pim J; Briels, Jeroen M; Schrader, Thomas; Milroy, Lech-Gustav; Brunsveld, Luc; Ottmann, Christian

    2017-07-24

    Interactions between proteins frequently involve recognition sequences based on multivalent binding events. Dimeric 14-3-3 adapter proteins are a prominent example and typically bind partner proteins in a phosphorylation-dependent mono- or bivalent manner. Herein we describe the development of a cucurbit[8]uril (Q8)-based supramolecular system, which in conjunction with the 14-3-3 protein dimer acts as a binary and bivalent protein assembly platform. We fused the phenylalanine-glycine-glycine (FGG) tripeptide motif to the N-terminus of the 14-3-3-binding epitope of the estrogen receptor α (ERα) for selective binding to Q8. Q8-induced dimerization of the ERα epitope augmented its affinity towards 14-3-3 through a binary bivalent binding mode. The crystal structure of the Q8-induced ternary complex revealed molecular insight into the multiple supramolecular interactions between the protein, the peptide, and Q8. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  2. A competitive strategy based on cucurbit[7]uril supramolecular interaction for simple and sensitive detection of dibucaine.

    Science.gov (United States)

    Li, Yan; Li, Chang-Feng; Du, Li-Ming; Feng, Jian-Xia; Liu, Hai-Long; Fu, Yun-Long

    2015-01-01

    In this work, the competitive interaction between dibucaine and three fluorescent probes (i.e., berberine, palmatine, and coptisine) for occupancy of the cucurbit[7]uril (CB[7]) cavity was studied by fluorescence spectra, UV-visible absorption spectra, (1)H NMR spectra, and theoretical calculations in acidic aqueous solution. Based on the fluorescence enhancement of berberine, palmatine, and coptisine upon binding with CB[7], respectively, a series of fluorescence detection methods for dibucaine were proposed. At the optimized conditions, the fluorescence intensity of berberine-CB[7], palmatine-CB[7], and coptisine-CB[7] complexes showed negative correlation to the concentration of dibucaine, which led to a series of simple and sensitive fluorescence methods for the determination of dibucaine for the first time. Linear ranges obtained in the detection of the dibucaine were 0.018-3.34 μmol L(-1), 0.032-4.47 μmol L(-1), and 0.079-4.42 μmol L(-1) with detection limits of 6.0 nmol L(-1), 12.0 nmol L(-1), and 25.0 nmol L(-1), respectively. Moreover, the proposed method was successfully applied for the determination of the drug in biological fluids. The competitive mode based on CB[7] superstructure provided a promising assay strategy for fluorescence detection in various potential applications.

  3. Controlled gelation kinetics of cucurbit[7]uril-adamantane cross-linked supramolecular hydrogels with competing guest molecules

    Science.gov (United States)

    Chen, Hao; Hou, Shengzhen; Ma, Haili; Li, Xu; Tan, Yebang

    2016-02-01

    Gelation kinetics of hydrogels is closely linked to many applications such as the development of injectable and printable hydrogels. However, the control of gelation kinetics without compromising the structure and other properties of the hydrogels, remains a challenge. Here, we demonstrate a method to control the gelation kinetics of cucurbit[7]uril-adamantane (CB[7]-AD) cross-linked supramolecular hydrogels by using competing guest molecules. The association between CB[7] and AD moieties on the polymer backbone was impeded by pre-occupying the CB[7] cavity with competing guest molecules. By using various guest molecules and concentrations, the gelation of the hydrogels could be varied from seconds to hours. The strong interaction of CB[7]-AD pair endue the hydrogels good mechanical properties and stability. Moreover, the binding of functionalized guest molecules of CB[7] moieties offers a facile approach for tailoring of the hydrogels’ scaffold. Combined with hydrogel injection and printing technology, this method offers an approach for the development of hydrogels with advanced temporal and spatial complexity.

  4. Laser Induced breakdown spectroscopy: A rapid tool for the identification and quantification of minerals in cucurbit seeds.

    Science.gov (United States)

    Singh, Jyotsana; Kumar, Rohit; Awasthi, Shikha; Singh, Vinti; Rai, A K

    2017-04-15

    Laser-induced breakdown spectroscopy (LIBS) was investigated to estimate the viability as a simple and rapid method for analysis of nutrient elements in seed kernels of cucurbits. LIBS spectra were recorded in the range of 200-975nm by using Q-switched Nd:YAG laser at 532nm (4ns, 10Hz) attached to echelle spectrometer with intensified charged coupled device (ICCD). The spectral analysis revealed the presence of several elements like C, O, N, Mg, Ca, Na and K in seeds. The quantification of elements (Mg, Ca, Na and K) through LIBS was done using calibration curve method in which all calibration curve shows good linearity (r>0.95). The result obtained through LIBS was in reasonable agreement with that obtained through atomic absorption spectroscopy (AAS). Principal Component Analysis (PCA) was also applied to the LIBS data for rapid categorization of seed samples belonging to same species although samples have similar nutrient elements. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. PH responsive self-assembly of cucurbit[7]urils and polystyrene-block- polyvinylpyridine micelles for hydrophobic drug delivery

    KAUST Repository

    Moosa, B.A.

    2013-01-01

    Polystyrene-block-polyvinylpyridine (PS-b-P4VP) polypseudorotaxanes with cucurbit[7]urils (CB[7]) were prepared from water soluble PS-b-P4VPH+ polymer and CB[7] in aqueous solution at room temperature. At acidic and neutral pH, the pyridinium block of PS-b-P4VP is protonated (PS-b-P4VPH +) pushing CB[7] to preferably host the P4VP block. At basic pH (pH 8), P4VP is not charged and thus is not able to strongly complex CB[7]. This phenomenon was verified further by monitoring the release of pyrene, a hydrophobic cargo model, from a PS-b-P4VPH+/CB[7] micellar membrane. Release study of UV active pyrene from the membrane at different pH values revealed that the system is only operational under basic conditions and that the host-guest interaction of CB[7] with P4VPH+ significantly slows down cargo release.

  6. Leaf anatomy and photosynthesis

    NARCIS (Netherlands)

    Berghuijs, H.N.C.

    2016-01-01

    Keywords: CO2 diffusion, C3 photosynthesis, mesophyll conductance, mesophyll resistance, re-assimilation, photorespiration, respiration, tomato Herman Nicolaas Cornelis Berghuijs (2016). Leaf anatomy and photosynthesis; unravelling the CO2 diffusion pathway in C3 leaves. PhD thesis. Wageningen Unive

  7. Synthesis of honeycomb-like palladium nanostructures by using cucurbit[7]uril and their catalytic activities for reduction of 4-nitrophenol

    Energy Technology Data Exchange (ETDEWEB)

    Premkumar, Thathan [Department of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 1 Oryong-dong, Buk-gu, Gwangju 500-712 (Korea, Republic of); The University College/Department of Chemistry, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Geckeler, Kurt E., E-mail: keg@gist.ac.kr [Department of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 1 Oryong-dong, Buk-gu, Gwangju 500-712 (Korea, Republic of); Department of Nanobio Materials and Electronics (WCU), Gwangju Institute of Science and Technology (GIST), 1 Oryong-dong, Buk-gu, Gwangju 500-712 (Korea, Republic of)

    2014-12-15

    An eco-friendly one-pot method to synthesize self-assembled palladium nanoclusters using a macrocycle, namely cucurbit[7]uril, in the alkaline medium without employing any special reducing or capping agents and/or external energy at room temperature is described. This greener approach, which utilizes water as a benign solvent and biocompatible cucurbit[7]uril as both reducing and protecting agents, can be applied to synthesize other noble metal nanoparticles such as gold, silver, and platinum. Owing to unique structural arrangement of cucurbit[7]uril, it was possible to prepare palladium nanoclusters of honeycomb-like structure irrespective of the reaction conditions. The honeycomb-like palladium nanoclusters were characterized using transmission electron microscopy (TEM), higher-resolution TEM (HR-TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), UV–vis, and FT-IR spectroscopy. Significantly, the synthesized palladium nanoclusters exhibited catalytic activity for the reduction reaction of 4-nitrophenol at room temperature. The approach launched here is easy, green, and user-friendly in contrast to the conventional techniques using polymers or surfactants and harsh reductants. - Highlights: • A simple and one-pot method to synthesis palladium nanostructures with honey-comb like structure. • The strategy established here does not require any harsh and toxic reducing agents. • It has a potential to be a general method for the synthesis of metal nanoparticles in water medium. • Palladium nanoclusters can be used as catalyst for the reduction reaction of 4-nitrophenol. • This system makes a novel platform for industrial and biomedical applications.

  8. A combined molecular dynamics simulation and quantum mechanics study on mercaptopurine interaction with the cucurbit [6,7] urils: Analysis of electronic structure.

    Science.gov (United States)

    Zaboli, Maryam; Raissi, Heidar

    2018-01-05

    In the current study, the probability of complex formation between mercaptopurine drug with cucurbit[6]urils and cucurbit[7]urils has been investigated. The calculations for geometry optimization of complexes have been carried out by means of DFT (B3LYP), DFT-D (B3LYP-D) and M06-2X methods. The Atoms In Molecules (AIM), Natural Bond Orbital (NBO), NMR, the density of states (DOSs) and frontier molecular orbital (MO) analyses have been done on the inclusion complexes. In addition, the UV-Vis spectra of the first eight states have been obtained by CAM-B3LYP/TD-DFT calculation. The obtained results of the complexation process reveal that CB[7]-DRG complexes are more favorable than that of CB[6]-DRG interactions. Furthermore, our theoretical results show that configurations III and I are the most stable configurations related to the CB[6]/DRG and CB[7]/DRG interactions, respectively. The positive ∇(2)ρ(r) and HC values at the bond critical points indicate that exist the weak H-bonds between CB[6] and CB[7] with H atoms of the drug molecule. The obtained negative binding energy values of CB[7]-DRG interaction in solution phase show the stability of these complexes in the aqueous medium. Also, all of the observed parameters of molecular dynamics simulation such as the number of contacts, hydrogen bonding, center-of-mass distance and van der Waals energy values confirm the encapsulation of mercaptopurine molecule inside the cucurbit[7]urils cavity at about 3.2ns. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Arabidopsis onset of leaf death mutants identify a regulatory pathway controlling leaf senescence

    NARCIS (Netherlands)

    Jing, Hai-Chun; Sturre, Marcel J.G.; Hille, Jacques; Dijkwel, Paul P.

    2002-01-01

    The onset of leaf senescence is controlled by leaf age and ethylene can promote leaf senescence within a specific age window. We exploited the interaction between leaf age and ethylene and isolated mutants with altered leaf senescence that are named as onset of leaf death (old) mutants. Early leaf

  10. Leaf absorbance and photosynthesis

    Science.gov (United States)

    Schurer, Kees

    1994-01-01

    The absorption spectrum of a leaf is often thought to contain some clues to the photosynthetic action spectrum of chlorophyll. Of course, absorption of photons is needed for photosynthesis, but the reverse, photosynthesis when there is absorption, is not necessarily true. As a check on the existence of absorption limits we measured spectra for a few different leaves. Two techniques for measuring absorption have been used, viz. the separate determination of the diffuse reflectance and the diffuse transmittance with the leaf at a port of an integrating sphere and the direct determination of the non-absorbed fraction with the leaf in the sphere. In a cross-check both methods yielded the same results for the absorption spectrum. The spectrum of a Fuchsia leaf, covering the short-wave region from 350 to 2500 nm, shows a high absorption in UV, blue and red, the well known dip in the green and a steep fall-off at 700 nm. Absorption drops to virtually zero in the near infrared, with subsequent absorptions, corresponding to the water absorption bands. In more detailed spectra, taken at 5 nm intervals with a 5 nm bandwidth, differences in chlorophyll content show in the different depths of the dip around 550 nm and in a small shift of the absorption edge at 700 nm. Spectra for Geranium (Pelargonium zonale) and Hibiscus (with a higher chlorophyll content) show that the upper limit for photosynthesis can not be much above 700 nm. No evidence, however, is to be seen of a lower limit for photosynthesis and, in fact, some experiments down to 300 nm still did not show a decrease of the absorption although it is well recognized that no photosynthesis results with 300 nm wavelengths.

  11. Leaf anatomy and photosynthesis

    OpenAIRE

    Berghuijs, H.N.C.

    2016-01-01

    Keywords: CO2 diffusion, C3 photosynthesis, mesophyll conductance, mesophyll resistance, re-assimilation, photorespiration, respiration, tomato Herman Nicolaas Cornelis Berghuijs (2016). Leaf anatomy and photosynthesis; unravelling the CO2 diffusion pathway in C3 leaves. PhD thesis. Wageningen University, Wageningen, The Netherlands, with summaries in English and Dutch. 286 pages Optimizing photosynthesis can contribute to improving crop yield, which is necessary to meet the increasing global...

  12. A rapid inoculation technique for assessing pathogenicity of Fusarium oxysporum f. sp. niveum and F. o. melonis on Cucurbits

    Science.gov (United States)

    Freeman, S.; Rodriguez, R.J.

    1993-01-01

    A continuous-dip inoculation technique for rapid assessment of pathogenicity of Fusarium oxysporum f. sp. niveum and F. o. melonis was developed. The method, adapted from a similar procedure for determining pathogenicity of Colletotrichum magna (causal agent of anthracnose of cucurbits), involves constant exposure of seedlings and cuttings (seedlings with root systems excised) of watermelon and muskmelon to conidial suspensions contained in small scintillation vials. Disease development in intact seedlings corresponded well to disease responses observed with the standard root-dip inoculation/pot assay. The continuous-dip inoculation technique resulted in rapid disease development, with 50% of watermelon cuttings dying after 4–6 days of exposure to F. o. niveum. A mortality of 30% also was observed in watermelon cuttings exposed to conidia of F. o. melonis, as opposed to only a 0–2.5% mortality in seedlings with intact roots. Disease response was similar with muskmelon seedlings and cuttings continuously dip-inoculated with F. o. melonis isolates. However, no disease symptoms were observed in muskmelon seedlings or cuttings inoculated with F. o. niveum. Four nonpathogenic isolates of F. oxysporum did not cause disease symptoms in either watermelon or muskmelon cuttings and seedlings when assayed by this technique. The proposed method enables a rapid screening of pathogenicity and requires less time, labor, and greenhouse space than the standard root-dip inoculation/pot assay. The reliability of the continuous-dip inoculation technique is limited, however, to exposure of intact seedlings at a concentration of 1 × 106conidia per milliliter; the method is not accurate at this range for excised seedlings.

  13. Sequence-specific, nanomolar peptide binding via cucurbit[8]uril-induced folding and inclusion of neighboring side chains.

    Science.gov (United States)

    Smith, Lauren C; Leach, David G; Blaylock, Brittney E; Ali, Omar A; Urbach, Adam R

    2015-03-18

    This paper describes the molecular recognition of the tripeptide Tyr-Leu-Ala by the synthetic receptor cucurbit[8]uril (Q8) in aqueous buffer with nanomolar affinity and exceptional specificity. This combination of characteristics, which also applies to antibodies, is desirable for applications in biochemistry and biotechnology but has eluded supramolecular chemists for decades. Building on prior knowledge that Q8 binds to peptides with N-terminal aromatic residues, a library screen of 105 peptides was designed to test the effects of residues adjacent to N-terminal Trp, Phe, or Tyr. The screen used tetramethylbenzobis(imidazolium) (MBBI) as a fluorescent indicator and resulted in the unexpected discovery that MBBI can serve not only as a turn-off sensor via the simultaneous inclusion of a Trp residue but also as a turn-on sensor via the competitive displacement of MBBI upon binding of Phe- or Tyr-terminated peptides. The unusual fluorescence response of the Tyr series prompted further investigation by (1)H NMR spectroscopy, electrospray ionization mass spectrometry, and isothermal titration calorimetry. From these studies, a novel binding motif was discovered in which only 1 equiv of peptide binds to Q8, and the side chains of both the N-terminal Tyr residue and its immediate neighbor bind within the Q8 cavity. For the peptide Tyr-Leu-Ala, the equilibrium dissociation constant value is 7.2 nM, whereas that of its sequence isomer Tyr-Ala-Leu is 34 μM. The high stability, recyclability, and low cost of Q8 combined with the straightforward incorporation of Tyr-Leu-Ala into recombinant proteins should make this system attractive for the development of biological applications.

  14. Biomass, virus concentration, and symptomatology of cucurbits infected by mild and severe strains of Papaya ringspot virus

    Directory of Open Access Journals (Sweden)

    Pacheco Davi Andrade

    2003-01-01

    Full Text Available Pre-immunization with mild strains of Papaya ringspot virus - type W (PRWV-W has allowed the mosaic disease to be controlled in different cucurbit species, with increases in marketable fruit yield. The objective of this study was to compare virus concentration, biomass and symptomatology of 'Caserta' zucchini squash, 'Menina Brasileira' long-neck squash and 'Crimson Sweet' watermelon plants infected by three mild strains and one severe strain of PRSV-W. Plants were inoculated at the cotyledonary stage, under greenhouse conditions, sampled at 7, 14, 21, 28 and 35 days after inoculation (DAI, and analyzed by PTA-ELISA. The severity of the symptoms was scored according to a scale from 1 to 5, and the fresh and dry biomass of the aerial part of the plants were evaluated at 40 DAI. Concentrations of the mild strains, based on absorbance values of the PTA-ELISA, were lower than the concentration of the severe strain for all species. The mild strains did not cause mosaic in infected plants of all species. Plants of zucchini squash and watermelon infected by the severe strain exhibited severe mosaic symptoms, but the same was not noticed for infected long-neck squash plants. Biomass values from zucchini squash and watermelon plants infected by the mild strains were 1.7 % to 12.4 % lower as compared to healthy plants. Biomass values of zucchini squash and watermelon plants infected by the severe strain presented greater reduction, varying from 29 % to 74 %. However, biomass values of long-neck squash plants infected by the mild and severe strains were similar for all treatments.

  15. Transmission of Squash vein yellowing virus to and From Cucurbit Weeds and Effects on Sweetpotato Whitefly (Hemiptera: Aleyrodidae) Behavior.

    Science.gov (United States)

    Shrestha, D; McAuslane, H J; Adkins, S T; Smith, H A; Dufault, N; Webb, S E

    2016-08-01

    Since 2003, growers of Florida watermelon [Citrullus lanatus (Thunb.) Matsum. and Nakai] have periodically suffered large losses from a disease caused by Squash vein yellowing virus (SqVYV), which is transmitted by the whitefly Middle East-Asia Minor 1 (MEAM1), formerly Bemisia tabaci (Gennadius) biotype B. Common cucurbit weeds like balsam apple (Momordica charantia L.) and smellmelon [Cucumis melo var. dudaim (L.) Naud.] are natural hosts of SqVYV, and creeping cucumber (Melothria pendula L.) is an experimental host. Study objectives were to compare these weeds and 'Mickylee' watermelon as sources of inoculum for SqVYV via MEAM1 transmission, to determine weed susceptibility to SqVYV, and to evaluate whitefly settling and oviposition behaviors on infected vs. mock-inoculated (inoculated with buffer only) creeping cucumber leaves. We found that the lowest percentage of watermelon recipient plants was infected when balsam apple was used as a source of inoculum. Watermelon was more susceptible to infection than balsam apple or smellmelon. However, all weed species were equally susceptible to SqVYV when inoculated by whitefly. For the first 5 h after release, whiteflies had no preference to settle on infected vs. mock-inoculated creeping cucumber leaves. After 24 h, whiteflies preferred to settle on mock-inoculated leaves, and more eggs were laid on mock-inoculated creeping cucumber leaves than on SqVYV-infected leaves. The transmission experiments (source of inoculum and susceptibility) show these weed species as potential inoculum sources of the virus. The changing settling preference of whiteflies from infected to mock-inoculated plants could lead to rapid spread of virus in the agroecosystem.

  16. The Property and Subject Classification of China Cucurbits and Vegetables%《中国瓜菜》性质及学科分类

    Institute of Scientific and Technical Information of China (English)

    李杨; 朱安; 房威; 张志转; 朱永和

    2012-01-01

    Classify China Cucurbits and Vegetables according to property and subject of journal based on quantity of literatures. 61.24% of itspapers in 2010 are relate to academic research and the literatures about horticulture account for 75. 13% of summation. The literatures of othersubject failed to obtain adequate influence as a result of small quantity. So China Cucurbits and Vegetables belongs to scholarly journal abouthorticulture.%根据期刊性质和学科分类方法,以文献数量为依据对《中国瓜菜》进行分类结果发现,《中国瓜菜》2010年刊登的论文61.24%属研究性论文,园艺类文献占当年发表文献总量的75.13%,其余学科文献均较少,不能划入相应学科,因此应将该刊归类为园艺类专业学术期刊.

  17. Seletividade de inseticidas, recomendados para cucurbitáceas para Trichogramma atopovirilia Oatman & Platner (Hymenoptera: Trichogrammatidae em condições de laboratório

    Directory of Open Access Journals (Sweden)

    Dirceu Pratissoli

    2011-10-01

    Full Text Available As brocas-das-cucurbitáceas Diaphania spp. são as principais pragas das cucurbitáceas, podendo ocasionar perdas de até 100% na produção. A fim de reduzir o uso de inseticidas, o controle biológico, aplicado com parasitoides do gênero Trichogramma, tem-se destacado. Objetivou-se avaliar a seletividade dos ingredientes ativos abamectina, tiacloprido e clorfenapir, para Trichogramma atopovirilia Oatman & Platner (Hymenoptera: Trichogrammatidae. Para isso, 20 fêmeas recém-emergidas de T. atopovirilla foram individualizadas, em tubos de vidro (2,5 cm de diâmetro x 8,5 cm de comprimento, e oferecidas cartelas com 30 ovos de Diaphania hyalinata (Linnaeus (Lepidoptera: Pyralidae, previamente imersas por cinco segundos em calda química. Os ingredientes ativos abamectina, tiacloprido e clorfenapir não afetaram o parasitismo de T. atopovirilia. Clorfenapir reduziu a emergência. Abamectina e tiacloprido são os mais recomendados no manejo integrado de pragas, pois foram os que se mostraram mais seletivos a T. atopovirilia em ovos de D. hyalinata.

  18. Comparing Leaf and Root Insertion

    Directory of Open Access Journals (Sweden)

    Jaco Geldenhuys

    2010-07-01

    Full Text Available We consider two ways of inserting a key into a binary search tree: leaf insertion which is the standard method, and root insertion which involves additional rotations. Although the respective cost of constructing leaf and root insertion binary search trees trees, in terms of comparisons, are the same in the average case, we show that in the worst case the construction of a root insertion binary search tree needs approximately 50% of the number of comparisons required by leaf insertion.

  19. Comparative leaf development in angiosperms.

    Science.gov (United States)

    Tsukaya, Hirokazu

    2014-02-01

    Recent accumulation of our knowledge on basic leaf development mechanisms in model angiosperm species has allowed us to pursue evolutionary development (evo/devo) studies of various kinds of leaf development. As a result, unexpected findings and clues have been unearthed aiding our understanding of the mechanisms involved in the diversity of leaf morphology, although the covered remain limited. In this review, we highlight recent findings of diversified leaf development in angiosperms. Copyright © 2013 The Author. Published by Elsevier Ltd.. All rights reserved.

  20. 7 CFR 29.2528 - Leaf.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.2528 Section 29.2528 Agriculture Regulations...-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2528 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf....

  1. 7 CFR 29.3033 - Leaf.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.3033 Section 29.3033 Agriculture Regulations... Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf....

  2. 7 CFR 29.3525 - Leaf.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.3525 Section 29.3525 Agriculture Regulations... Type 95) § 29.3525 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf....

  3. Leaf growth of contrasting Poa species

    NARCIS (Netherlands)

    Fiorani, Fabio

    2002-01-01

    In the grass genus Poa a wide variation in final leaf size and leaf growth rate exists. In this thesis leaf growth was analyzed at different levels. At the cellular level, inherent variation in leaf elongation rate and final leaf size was correlated to the length of the elongation zone and to merist

  4. 7 CFR 29.1028 - Leaf.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.1028 Section 29.1028 Agriculture Regulations... Type 92) § 29.1028 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf....

  5. Detection of tomato yellow leaf curl Thailand virus by PCR without DNA extraction.

    Science.gov (United States)

    Ieamkhang, Supaporn; Riangwong, Lumpueng; Chatchawankanphanich, Orawan

    2005-11-01

    We report the simple and rapid method for detection of tomato yellow leaf curl Thailand virus (TYLCTHV) based on the direct capture of virus particles to the surface of a polymerase chain reaction (PCR) tube. This method allowed PCR without the time-consuming procedures of DNA extraction from infected plant tissue. A small amount of tomato tissue (approximately 10 mg) was ground in extraction buffer to release viruses from plant tissues. The constituents of the plant extract that might inhibit PCR activity were discarded by washing the tube with PBST buffer before adding the PCR mixture to the tube. This method was used for detection of TYLCTHV with plant sap solution diluted up to 1:20,000 and was more sensitive than an enzyme-linked immunosorbent assay (ELISA) method. In addition, this method can be used for detection of TYLCTHV in viruliferous whiteflies. The PCR tubes with captured TYLCTHV could be used for PCR, after storage at 4 degrees C for 4 wk. The method presented here was used for detection of begomoviruses in cucurbit and pepper. In addition, this method was effectively used to detect papaya ringspot virus in papaya and zucchini yellow mosaic virus in cucumber by reverse transcriptase (RT)-PCR.

  6. (TECTONA GRANDIS LEAF POWDER

    Directory of Open Access Journals (Sweden)

    Yash Mishra

    2015-01-01

    Full Text Available In this study, the adsorption potential of Teak (Tectona grandis leaf powder (TLP toremove Methylene blue (MB and Malachite Green (MG dye molecules from aqueoussolution was investigated. Batch experiments were conducted to evaluate the influenceof operational parameters such as, pH (2−9, adsorbent dosage (1−7 g/L, contact time(15−150 minutes and initial dye concentration (20−120 mg/L at stirring speed of 150rpm for the adsorption of MB and MG on TLP. Maximum removal efficiency of 98.4%and 95.1% was achieved for MB and MG dye, respectively. The experimentalequilibrium data were analysed using Langmuir, Freundlich and Temkin isothermmodels and it was found that, it fitted well to the Freundlich isotherm model. Thesurface structure and morphology of the adsorbent was characterized using scanningelectron microscopy (SEM and the presence of functional groups and its interactionwith the dye molecules were analysed using Fourier transform infrared spectroscopy(FTIR. Based on the investigation, it has been demonstrated that the teak leaf powderhas good potential for effective adsorption of methylene blue and malachite green dye.

  7. The artificial leaf.

    Science.gov (United States)

    Nocera, Daniel G

    2012-05-15

    To convert the energy of sunlight into chemical energy, the leaf splits water via the photosynthetic process to produce molecular oxygen and hydrogen, which is in a form of separated protons and electrons. The primary steps of natural photosynthesis involve the absorption of sunlight and its conversion into spatially separated electron-hole pairs. The holes of this wireless current are captured by the oxygen evolving complex (OEC) of photosystem II (PSII) to oxidize water to oxygen. The electrons and protons produced as a byproduct of the OEC reaction are captured by ferrodoxin of photosystem I. With the aid of ferrodoxin-NADP(+) reductase, they are used to produce hydrogen in the form of NADPH. For a synthetic material to realize the solar energy conversion function of the leaf, the light-absorbing material must capture a solar photon to generate a wireless current that is harnessed by catalysts, which drive the four electron/hole fuel-forming water-splitting reaction under benign conditions and under 1 sun (100 mW/cm(2)) illumination. This Account describes the construction of an artificial leaf comprising earth-abundant elements by interfacing a triple junction, amorphous silicon photovoltaic with hydrogen- and oxygen-evolving catalysts made from a ternary alloy (NiMoZn) and a cobalt-phosphate cluster (Co-OEC), respectively. The latter captures the structural and functional attributes of the PSII-OEC. Similar to the PSII-OEC, the Co-OEC self-assembles upon oxidation of an earth-abundant metal ion from 2+ to 3+, may operate in natural water at room temperature, and is self-healing. The Co-OEC also activates H(2)O by a proton-coupled electron transfer mechanism in which the Co-OEC is increased by four hole equivalents akin to the S-state pumping of the Kok cycle of PSII. X-ray absorption spectroscopy studies have established that the Co-OEC is a structural relative of Mn(3)CaO(4)-Mn cubane of the PSII-OEC, where Co replaces Mn and the cubane is extended in a

  8. A wind-oriented sticky trap for evaluating the behavioural response of diabrotica speciosa (germar) to bitter cucurbit extracts

    Science.gov (United States)

    Cucurbitacins attract many species of Luperini leaf beetles, for which they have been studied and applied in traps and toxic baits. Males and females feed avidly on these compounds, but field trials reveal that males are far more attracted to them than females. A wind oriented baited sticky trap was...

  9. The worldwide leaf economics spectrum

    NARCIS (Netherlands)

    Wright, I.J.; Reich, P.B.; Westoby, M.; Ackerly, D.D.; Baruch, Z.; Bongers, F.J.J.M.; Cavender-Bares, J.; Chapin, T.; Cornelissen, J.H.C.; Diemer, M.; Flexas, J.; Garnier, E.; Groom, P.K.; Gulias, J.; Hikosaka, K.; Lamont, B.B.; Lee, T.; Lee, W.; Lusk, C.; Midgley, J.J.; Navas, M.L.; Niinements, Ü.; Oleksyn, J.; Osada, N.; Poorter, H.; Poot, P.; Prior, L.; Pyankov, V.I.; Roumet, C.; Thomas, S.C.; Tjoelker, M.G.; Veneklaas, E.J.; Villar, R.

    2004-01-01

    Bringing together leaf trait data spanning 2,548 species and 175 sites we describe, for the first time at global scale, a universal spectrum of leaf economics consisting of key chemical, structural and physiological properties. The spectrum runs from quick to slow return on investments of nutrients

  10. Leaf chlorophyll content as a proxy for leaf photosynthetic capacity.

    Science.gov (United States)

    Croft, Holly; Chen, Jing M; Luo, Xiangzhong; Bartlett, Paul; Chen, Bin; Staebler, Ralf M

    2017-09-01

    Improving the accuracy of estimates of forest carbon exchange is a central priority for understanding ecosystem response to increased atmospheric CO2 levels and improving carbon cycle modelling. However, the spatially continuous parameterization of photosynthetic capacity (Vcmax) at global scales and appropriate temporal intervals within terrestrial biosphere models (TBMs) remains unresolved. This research investigates the use of biochemical parameters for modelling leaf photosynthetic capacity within a deciduous forest. Particular attention is given to the impacts of seasonality on both leaf biophysical variables and physiological processes, and their interdependent relationships. Four deciduous tree species were sampled across three growing seasons (2013-2015), approximately every 10 days for leaf chlorophyll content (ChlLeaf ) and canopy structure. Leaf nitrogen (NArea ) was also measured during 2014. Leaf photosynthesis was measured during 2014-2015 using a Li-6400 gas-exchange system, with A-Ci curves to model Vcmax. Results showed that seasonality and variations between species resulted in weak relationships between Vcmax normalized to 25°C (Vcmax25) and NArea (R(2)  = 0.62, P models to derive ChlLeaf . TBMs largely treat photosynthetic parameters as either fixed constants or varying according to leaf nitrogen content. This research challenges assumptions that simple NArea -Vcmax25 relationships can reliably be used to constrain photosynthetic capacity in TBMs, even within the same plant functional type. It is suggested that ChlLeaf provides a more accurate, direct proxy for Vcmax25 and is also more easily retrievable from satellite data. These results have important implications for carbon modelling within deciduous ecosystems. © 2017 Her Majesty the Queen in Right of Canada.

  11. Biological Control of Fusarium oxysporum f. sp. melonis, the Causal Agent of Root Rot Disease of Greenhouse Cucurbits in Kerman Province of Iran

    Directory of Open Access Journals (Sweden)

    Sara Shafii Bafti

    2005-01-01

    Full Text Available Antagonistic activity of 178 soil actinomycete isolates was assayed against Fusarium oxysporum f. sp. melonis Schlecht, Emend (Snyde and Hansen cause of root rot and fusarium wilt of greenhouse cucurbits in Kerman Province, southeast of Iran. From tested isolates, Streptomyces olivaceus (strain 115 showed anti-fusarium activity revealed through screening and bioassays by agar disk and well-diffusion methods. The active strain was grown in submerged cultures for determination of growth curve and preparation of crude extract for further biological characterizations. Antifungal activity was fungistatic type on the pathogen mycelia. It is prominent that amending greenhouse soil mix with the S. olivaceus (strain 115 will reduce crop losses by the pathogen.

  12. The effect of cucurbit[7]uril on photophysical properties of aqueous solution of 3,3‧-diethylthiacarbocyanine iodide dye

    Science.gov (United States)

    Petrov, N. Kh.; Ivanov, D. A.; Golubkov, D. V.; Gromov, S. P.; Alfimov, M. V.

    2009-09-01

    Photophysical properties of aqueous solutions of 3,3'-diethyl-thiacarbocyanine iodide (DTCI) was studied in the presence of cucurbit[7]uril (CB7) by means of absorption and fluorescence spectroscopy. The addition of CB7 decreases the 550 nm peak of the DTCI absorption spectrum and concomitantly transforms the familiar shoulder at 510 nm into a pronounced peak; fluorescence was found to decay monoexponentially with a lifetime of 0.12 ns in aqueous DTCI solution without CB7 and 1.07 ns in the presence of CB7. The association constant of 1:1 complexes of DTCI with CB7 has been determined to be K = (2.8 ± 0.2) × 10 4 M -1. The Rullière model of photoisoomerisation of cyanines was used for explaining the main features of the effect observed.

  13. Unusual Complex Formation and Chemical Reaction of Haloacetate Anion on the Exterior Surface of Cucurbit[6]uril in the Gas Phase

    Science.gov (United States)

    Choi, Tae Su; Ko, Jae Yoon; Heo, Sung Woo; Ko, Young Ho; Kim, Kimoon; Kim, Hugh I.

    2012-10-01

    Noncovalent interactions of cucurbit[6]uril (CB[6]) with haloacetate and halide anions are investigated in the gas phase using electrospray ionization ion mobility mass spectrometry. Strong noncovalent interactions of monoiodoacetate, monobromoacetate, monochloroacetate, dichloroacetate, and trichloroacetate on the exterior surface of CB[6] are observed in the negative mode electrospray ionization mass spectra. The strong binding energy of the complex allows intramolecular SN2 reaction of haloacetate, which yields externally bound CB[6]-halide complex, by collisional activation. Utilizing ion mobility technique, structures of exteriorly bound CB[6] complexes of haloacetate and halide anions are confirmed. Theoretically determined low energy structures using density functional theory (DFT) further support results from ion mobility studies. The DFT calculation reveals that the binding energy and conformation of haloacetate on the CB[6] surface affect the efficiency of the intramolecular SN2 reaction of haloacetate, which correlate well with the experimental observation.

  14. Maize YABBY genes drooping leaf1 and drooping leaf2 affect agronomic traits by regulating leaf architecture

    Science.gov (United States)

    Leaf architectural traits, such as length, width and angle, directly influence canopy structure and light penetration, photosynthate production and overall yield. We discovered and characterized a maize (Zea mays) mutant with aberrant leaf architecture we named drooping leaf1 (drl1), as leaf blades ...

  15. Active suppression of a leaf meristem orchestrates determinate leaf growth.

    Science.gov (United States)

    Alvarez, John Paul; Furumizu, Chihiro; Efroni, Idan; Eshed, Yuval; Bowman, John L

    2016-10-06

    Leaves are flat determinate organs derived from indeterminate shoot apical meristems. The presence of a specific leaf meristem is debated, as anatomical features typical of meristems are not present in leaves. Here we demonstrate that multiple NGATHA (NGA) and CINCINNATA-class-TCP (CIN-TCP) transcription factors act redundantly, shortly after leaf initiation, to gradually restrict the activity of a leaf meristem in Arabidopsis thaliana to marginal and basal domains, and that their absence confers persistent marginal growth to leaves, cotyledons and floral organs. Following primordia initiation, the restriction of the broadly acting leaf meristem to the margins is mediated by the juxtaposition of adaxial and abaxial domains and maintained by WOX homeobox transcription factors, whereas other marginal elaboration genes are dispensable for its maintenance. This genetic framework parallels the morphogenetic program of shoot apical meristems and may represent a relic of an ancestral shoot system from which seed plant leaves evolved.

  16. Leaf Relative Water Content Estimated from Leaf Reflectance and Transmittance

    Science.gov (United States)

    Vanderbilt, Vern; Daughtry, Craig; Dahlgren, Robert

    2016-01-01

    Remotely sensing the water status of plants and the water content of canopies remain long term goals of remote sensing research. In the research we report here, we used optical polarization techniques to monitor the light reflected from the leaf interior, R, as well as the leaf transmittance, T, as the relative water content (RWC) of corn (Zea mays) leaves decreased. Our results show that R and T both change nonlinearly. The result show that the nonlinearities cancel in the ratio R/T, which appears linearly related to RWC for RWC less than 90%. The results suggest that potentially leaf water status and perhaps even canopy water status could be monitored starting from leaf and canopy optical measurements.

  17. Exogenously applied dsRNA molecules deriving from the Zucchini yellow mosaic virus (ZYMV) genome move systemically and protect cucurbits against ZYMV.

    Science.gov (United States)

    Kaldis, Athanasios; Berbati, Margarita; Melita, Ourania; Reppa, Chrysavgi; Holeva, Maria; Otten, Patricia; Voloudakis, Andreas

    2017-06-16

    Zucchini yellow mosaic virus (ZYMV) causes serious damage in a large number of cucurbits, and control measures are necessary. Transgenic cucurbits expressing parts of the ZYMV genome have been shown to be resistant to the cognate virus. A non-transgenic approach involving the exogenous application of double-stranded RNA (dsRNA) has also been shown to induce resistance in tobacco against Cucumber mosaic virus (CMV) and Tobacco mosaic virus (TMV). In the present study, dsRNA molecules derived from the helper component-proteinase (HC-Pro) and coat protein (CP) genes of the ZYMV_DE_2014 isolate were produced in vitro. On exogenous dsRNA application in cucumber, watermelon and squash plants, dsRNA HC-Pro conferred resistance of 82%, 50% and 18%, and dsRNA CP molecules of 70%, 43% and 16%, respectively. On deep sequencing analysis of ZYMV-infected watermelon, hot-spot regions for viral small interfering RNAs (vsiRNAs) in the genome of ZYMV were identified. Stem-loop reverse transcription-polymerase chain reaction (RT-PCR) detection of selected 21-nucleotide-long vsiRNAs in plants that received only dsRNA molecules suggested that the dsRNAs exogenously applied onto plants were successfully diced, thus initiating RNA silencing. dsRNA molecules were found to be progressively degraded in planta, and strongly detected by semi-quantitative RT-PCR for at least 9 days after exogenous application. Moreover, dsRNA molecules were detected in systemic tissue of watermelon and squash, showing that dsRNA is transported long distances in these plants. © 2017 BSPP AND JOHN WILEY & SONS LTD.

  18. Effect of Plant Growth Regulators on Leaf Number, Leaf Area and Leaf Dry Matter in Grape

    Directory of Open Access Journals (Sweden)

    Zahoor Ahmad BHAT

    2011-03-01

    Full Text Available Influence of phenylureas (CPPU and brassinosteriod (BR along with GA (gibberellic acid were studied on seedless grape vegetative characteristics like leaf number, leaf area and leaf dry matter. Growth regulators were sprayed on the vines either once (7 days after fruit set or 15 days after fruit set or twice (7+15 days after fruit set. CPPU 2 ppm+BR 0.4 ppm+GA 25 ppm produced maximum number of leaves (18.78 while as untreated vines produced least leaf number (16.22 per shoot. Maximum leaf area (129.70 cm2 and dry matter content (26.51% was obtained with higher CPPU (3 ppm and BR (0.4 ppm combination along with GA 25 ppm. Plant growth regulators whether naturally derived or synthetic are used to improve the productivity and quality of grapes. The relatively high value of grapes justifies more expensive inputs. A relatively small improvement in yield or fruit quality can justify the field application of a very costly product. Application of new generation growth regulators like brassinosteroids and phenylureas like CPPU have been reported to increase the leaf number as well as leaf area and dry matter thereby indirectly influencing the fruit yield and quality in grapes.

  19. Cucurbit[n]uril-Based Microcapsules Self-Assembled within Microfluidic Droplets: A Versatile Approach for Supramolecular Architectures and Materials.

    Science.gov (United States)

    Liu, Ji; Lan, Yang; Yu, Ziyi; Tan, Cindy S Y; Parker, Richard M; Abell, Chris; Scherman, Oren A

    2017-02-21

    of development in the field of monodisperse supramolecular microcapsules, fabricated through the integration of traditional microfluidic techniques and interfacial host-guest chemistry, specifically cucurbit[n]uril (CB[n])-mediated host-guest interactions. Three different strategies, colloidal particle-driven assembly, interfacial condensation-driven assembly and electrostatic interaction-driven assembly, are classified and discussed in detail, presenting the methodology involved in each microcapsule formation process. We highlight the state-of-the-art in design and control over structural complexity with desirable functionality, as well as promising applications, such as cargo delivery stemming from the assembled microcapsules. On account of its dynamic nature, the CB[n]-mediated host-guest complexation has demonstrated efficient response toward various external stimuli such as UV light, pH change, redox chemistry, and competitive guests. Herein, we also demonstrate different microcapsule modalities, which are engineered with CB[n] host-guest chemistry and also can be disrupted with the aid of external stimuli, for triggered release of payloads. In addition to the overview of recent achievements and current limitations of these microcapsules, we finally summarize several perspectives on tunable cargo loading and triggered release, directions, and challenges for this technology, as well as possible strategies for further improvement, which will lead to substainitial progress of host-guest chemistry in supramolecular architectures and materials.

  20. 7 CFR 29.3528 - Leaf surface.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf surface. 29.3528 Section 29.3528 Agriculture... Type 95) § 29.3528 Leaf surface. The roughness or smoothness of the web or lamina of a tobacco leaf. Leaf surface is affected to some extent by the size and shrinkage of the veins or fibers (See...

  1. 7 CFR 29.3036 - Leaf surface.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf surface. 29.3036 Section 29.3036 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Leaf surface. The smoothness or roughness of the web or lamina of a tobacco leaf. Leaf surface...

  2. Genetics of Ophraella leaf beetles

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This proposal is to collect samples of each species of Ophraella leaf beetle encountered, not to exceed 50 specimens per species, for genetic analysis using DNA...

  3. Agave Americana Leaf Fibers

    Directory of Open Access Journals (Sweden)

    Ashish Hulle

    2015-02-01

    Full Text Available The growing environmental problems, the problem of waste disposal and the depletion of non-renewable resources have stimulated the use of green materials compatible with the environment to reduce environmental impacts. Therefore, there is a need to design products by using natural resources. Natural fibers seem to be a good alternative since they are abundantly available and there are a number of possibilities to use all the components of a fiber-yielding crop; one such fiber-yielding plant is Agave Americana. The leaves of this plant yield fibers and all the parts of this plant can be utilized in many applications. The “zero-waste” utilization of the plant would enable its production and processing to be translated into a viable and sustainable industry. Agave Americana fibers are characterized by low density, high tenacity and high moisture absorbency in comparison with other leaf fibers. These fibers are long and biodegradable. Therefore, we can look this fiber as a sustainable resource for manufacturing and technical applications. Detailed discussion is carried out on extraction, characterization and applications of Agave Americana fiber in this paper.

  4. Why do leaf-tying caterpillars abandon their leaf ties?

    Directory of Open Access Journals (Sweden)

    Michelle Sliwinski

    2013-09-01

    Full Text Available Leaf-tying caterpillars act as ecosystem engineers by building shelters between overlapping leaves, which are inhabited by other arthropods. Leaf-tiers have been observed to leave their ties and create new shelters (and thus additional microhabitats, but the ecological factors affecting shelter fidelity are poorly known. For this study, we explored the effects of resource limitation and occupant density on shelter fidelity and assessed the consequences of shelter abandonment. We first quantified the area of leaf material required for a caterpillar to fully develop for two of the most common leaf-tiers that feed on white oak, Quercus alba. On average, Psilocorsis spp. caterpillars consumed 21.65 ± 0.67 cm2 leaf material to complete development. We also measured the area of natural leaf ties found in a Maryland forest, to determine the distribution of resources available to caterpillars in situ. Of 158 natural leaf ties examined, 47% were too small to sustain an average Psilocorsis spp. caterpillar for the entirety of its development. We also manipulated caterpillar densities within experimental ties on potted trees to determine the effects of cohabitants on the likelihood of a caterpillar to leave its tie. We placed 1, 2, or 4 caterpillars in ties of a standard size and monitored the caterpillars twice daily to track their movement. In ties with more than one occupant, caterpillars showed a significantly greater propensity to leave their tie, and left sooner and at a faster rate than those in ties as single occupants. To understand the consequences of leaf tie abandonment, we observed caterpillars searching a tree for a site to build a shelter in the field. This is a risky behavior, as 17% of the caterpillars observed died while searching for a shelter site. Caterpillars that successfully built a shelter traveled 110 ± 20 cm and took 28 ± 7 min to find a suitable site to build a shelter. In conclusion, leaf-tying caterpillars must frequently

  5. 瓜菜类病原细菌耐药外排泵RND研究进展%Advances in RND-type multi-drug efflux pumps from cucurbit and veg-etable pathogenic bacteria

    Institute of Scientific and Technical Information of China (English)

    王真; 赵廷昌; 杨玉文; 关巍; 胡俊

    2016-01-01

    近年来,瓜菜类作物病原细菌的耐药性日益增强,增加了瓜菜相关病害防治的难度。存在于瓜菜作物病原细菌中的外排泵耐药结节分化家族(RND)与细菌的耐药性及细菌/植物互作关系密切。笔者根据有关文献综述了RND外排泵的结构与功能、细菌/植物互作过程中外排泵的作用以及外排泵抑制剂(EPIS)的相关研究进展,为瓜类和蔬菜类作物病原细菌耐药性的研究提供参考。%In recent years, drug resistance of bacteria causing diseases on cucurbits and vegetables has been increasingly re⁃ported which caused huge difficluties in cucurbit and vegetable prevention. Resistance-nodulation-division family (RND) is one of the most important efflux pump family in cucurbit and vegetable pathogenic bacteria, which is closely related to bacte⁃ria multidrug resistance and interactions between pathogenic bacteria and plants. We describe structures and functions of RND efflux pumps, relationships between efflux pumps and bacterial/plant interactions as well as the relevant research of ef⁃flux pump inhibitors (EPIS). This review will provide references for further studies on drug resistance of cucurbit and vegeta⁃ble pathogenic bacteria.

  6. The antagonistic strain Bacillus subtilis UMAF6639 also confers protection to melon plants against cucurbit powdery mildew by activation of jasmonate- and salicylic acid-dependent defence responses.

    Science.gov (United States)

    García-Gutiérrez, Laura; Zeriouh, Houda; Romero, Diego; Cubero, Jaime; de Vicente, Antonio; Pérez-García, Alejandro

    2013-05-01

    Biological control of plant diseases has gained acceptance in recent years. Bacillus subtilis UMAF6639 is an antagonistic strain specifically selected for the efficient control of the cucurbit powdery mildew fungus Podosphaera fusca, which is a major threat to cucurbits worldwide. The antagonistic activity relies on the production of the antifungal compounds iturin and fengycin. In a previous study, we found that UMAF6639 was able to induce systemic resistance (ISR) in melon and provide additional protection against powdery mildew. In the present work, we further investigated in detail this second mechanism of biocontrol by UMAF6639. First, we examined the signalling pathways elicited by UMAF6639 in melon plants, as well as the defence mechanisms activated in response to P. fusca. Second, we analysed the role of the lipopeptides produced by UMAF6639 as potential determinants for ISR activation. Our results demonstrated that UMAF6639 confers protection against cucurbit powdery mildew by activation of jasmonate- and salicylic acid-dependent defence responses, which include the production of reactive oxygen species and cell wall reinforcement. We also showed that surfactin lipopeptide is a major determinant for stimulation of the immune response. These results reinforce the biotechnological potential of UMAF6639 as a biological control agent.

  7. Potential threat of a new pathotype of Papaya leaf distortion mosaic virus infecting transgenic papaya resistant to Papaya ringspot virus.

    Science.gov (United States)

    Bau, H-J; Kung, Y-J; Raja, J A J; Chan, S-J; Chen, K-C; Chen, Y-K; Wu, H-W; Yeh, S-D

    2008-07-01

    A virus identified as a new pathotype of Papaya leaf distortion mosaic virus (PLDMV, P-TW-WF) was isolated from diseased papaya in an isolated test-field in central Taiwan, where transgenic papaya lines resistant to Papaya ringspot virus (PRSV) were evaluated. The infected plants displayed severe mosaic, distortion and shoe-stringing on leaves; stunting in apex; and water-soaking on petioles and stems. This virus, which did not react in enzyme-linked immunosorbent assay with the antiserum to the PRSV coat protein, infected only papaya, but not the other 18 plant species tested. Virions studied under electron microscope exhibited morphology and dimensions of potyvirus particles. Reverse transcription-polymerase chain reaction conducted using potyvirus-specific primers generated a 1,927-nucleotide product corresponding to the 3' region of a potyvirus, showing high sequence identity to the CP gene and 3' noncoding region of PLDMV. Search for similar isolates with the antiserum against CP of P-TW-WF revealed scattered occurrence of PLDMV in Taiwan. Phylogenetic analysis of PLDMV isolates of Taiwan and Japan indicated that the Taiwan isolates belong to a separate genetic cluster. Since all the Taiwan isolates infected only papaya, unlike the cucurbit-infecting Japanese P type isolates, the Taiwan isolates are considered a new pathotype of PLDMV. Susceptibility of all our PRSV-resistant transgenic papaya lines to PLDMV indicates that the virus is an emerging threat for the application of PRSV-resistant transgenic papaya in Taiwan and elsewhere.

  8. Biophysical control of leaf temperature

    Science.gov (United States)

    Dong, N.; Prentice, I. C.; Wright, I. J.

    2014-12-01

    In principle sunlit leaves can maintain their temperatures within a narrower range than ambient temperatures. This is an important and long-known (but now overlooked) prediction of energy balance theory. Net radiation at leaf surface in steady state (which is reached rapidly) must be equal to the combination of sensible and latent heat exchanges with surrounding air, the former being proportional to leaf-to-air temperature difference (ΔT), the latter to the transpiration rate. We present field measurements of ΔT which confirm the existence of a 'crossover temperature' in the 25-30˚C range for species in a tropical savanna and a tropical rainforest environment. This finding is consistent with a simple representation of transpiration as a function of net radiation and temperature (Priestley-Taylor relationship) assuming an entrainment factor (ω) somewhat greater than the canonical value of 0.26. The fact that leaves in tropical forests are typically cooler than surrounding air, often already by solar noon, is consistent with a recently published comparison of MODIS day-time land-surface temperatures with air temperatures. Theory further predicts a strong dependence of leaf size (which is inversely related to leaf boundary-layer conductance, and therefore to absolute magnitude of ΔT) on moisture availability. Theoretically, leaf size should be determined by either night-time constraints (risk of frost damage to active leaves) or day-time constraints (risk of heat stress damage),with the former likely to predominate - thereby restricting the occurrence of large leaves - at high latitudes. In low latitudes, daytime maximum leaf size is predicted to increase with temperature, provided that water is plentiful. If water is restricted, however, transpiration cannot proceed at the Priestley-Taylor rate, and it quickly becomes advantageous for plants to have small leaves, which do not heat up much above the temperature of their surroundings. The difference between leaf

  9. RELATIONSHIP BETWEEN MANGOSTEEN LEAF NITROGEN CONTENTS AND LEAF SPAD VALUES

    Directory of Open Access Journals (Sweden)

    Eko Setiawan

    2014-03-01

    Full Text Available We investigated nitrogen contents on mangosteen leaf and related on leaf SPAD value. The experiment was conducted using mangosteen trees grown in commercial orchard in Bogor, Indonesia during May to October 2010. Mangosteen trees of 3 different ages, young (20-year-old, middle-aged (35-year-old, and old (50-year-old trees, each of five trees, were selected for study, and the canopy of each tree was divided into 9 sectors based on height (bottom, middle, top and width (inner, center, outer. SPAD values had a negative correlation with leaf N content in all ages and could be explained by regressionl equations N level (% DW = -0.0099 × SPAD + 2.2366; R² = 0.91; N level (% DW = -0.0177 × SPAD + 2.8001; R² = 0.67; and N level (% DW = -0.0187 × SPAD + 2.7785; R² = 0.45 in young, middle-aged and old trees, respectively. It is suggested that the SPAD value determined by a portable chlorophyll meter can be used to obtain a quick estimation of mangosteen leaf N status. Keywords: age, fruiting position, Garcinia mangostana L., nitrogen, SPAD

  10. A leaf detection method using image sequences and leaf movement

    NARCIS (Netherlands)

    Hemming, J.; Henten, van E.J.; Tuijl, van B.A.J.; Bontsema, J.

    2005-01-01

    Besides harvesting the fruits, a very time demanding task is removing old leaves from cucumber and tomato plants grown in greenhouses. To be able to automate this process by a robot, a leaf detection method is required. One possibility for the detection is to exploit the different dynamic behaviour

  11. Spectral reflectance relationships to leaf water stress

    Science.gov (United States)

    Ripple, William J.

    1986-01-01

    Spectral reflectance data were collected from detached snapbean leaves in the laboratory with a multiband radiometer. Four experiments were designed to study the spectral response resulting from changes in leaf cover, relative water content of leaves, and leaf water potential. Spectral regions included in the analysis were red (630-690 nm), NIR (760-900 nm), and mid-IR (2.08-2.35 microns). The red and mid-IR bands showed sensitivity to changes in both leaf cover and relative water content of leaves. The NIR was only highly sensitive to changes in leaf cover. Results provided evidence that mid-IR reflectance was governed primarily by leaf moisture content, although soil reflectance was an important factor when leaf cover was less than 100 percent. High correlations between leaf water potentials and reflectance were attributed to covariances with relative water content of leaves and leaf cover.

  12. LEAF: A Microcomputer Program for Constructing the Tukey Stem and Leaf Graph.

    Science.gov (United States)

    Pascale, Pietro J.; Smith, Joseph

    1986-01-01

    This paper presents a BASIC microcomputer program that constructs the Tukey (1977) stem and leaf graph. Options within the LEAF program include a modified stem and leaf where the stem is split and a parallel stem and leaf graph where two separate sets of data are displayed from a common stem. (Author)

  13. 7 CFR 29.2529 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.2529 Section 29.2529 Agriculture...-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2529 Leaf scrap. A byproduct of unstemmed tobacco. Leaf scrap results from handling unstemmed tobacco and consists of loose and tangled whole...

  14. 7 CFR 29.6022 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.6022 Section 29.6022 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6022 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap...

  15. 7 CFR 29.3526 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.3526 Section 29.3526 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 95) § 29.3526 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap results from...

  16. 7 CFR 29.3034 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.3034 Section 29.3034 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Leaf scrap. A by-product of unstemmed tobacco. Leaf scrap results from handling unstemmed tobacco...

  17. 7 CFR 29.3035 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.3035 Section 29.3035 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Leaf structure. The cell development of a leaf as indicated by its porosity or solidity. (See...

  18. 7 CFR 29.3527 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.3527 Section 29.3527 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 95) § 29.3527 Leaf structure. The cell development of a leaf as indicated by its porosity....

  19. 7 CFR 29.6023 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.6023 Section 29.6023 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6023 Leaf structure. The cell development of a leaf as indicated by...

  20. 7 CFR 29.1030 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.1030 Section 29.1030 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 92) § 29.1030 Leaf structure. The cell development of a leaf as indicated by its porosity....

  1. Comparison of half and full-leaf shape feature extraction for leaf classification

    Science.gov (United States)

    Sainin, Mohd Shamrie; Ahmad, Faudziah; Alfred, Rayner

    2016-08-01

    Shape is the main information for leaf feature that most of the current literatures in leaf identification utilize the whole leaf for feature extraction and to be used in the leaf identification process. In this paper, study of half-leaf features extraction for leaf identification is carried out and the results are compared with the results obtained from the leaf identification based on a full-leaf features extraction. Identification and classification is based on shape features that are represented as cosines and sinus angles. Six single classifiers obtained from WEKA and seven ensemble methods are used to compare their performance accuracies over this data. The classifiers were trained using 65 leaves in order to classify 5 different species of preliminary collection of Malaysian medicinal plants. The result shows that half-leaf features extraction can be used for leaf identification without decreasing the predictive accuracy.

  2. pH Responsive Self-Assembly of Cucurbit[7]urils and Polystyrene-Block-Polyvinylpyridine Micelles for Hydrophobic Drug Delivery

    Directory of Open Access Journals (Sweden)

    Basem A. Moosa

    2013-01-01

    Full Text Available Polystyrene-block-polyvinylpyridine (PS-b-P4VP polypseudorotaxanes with cucurbit[7]urils (CB[7] were prepared from water soluble PS-b-P4VPH+ polymer and CB[7] in aqueous solution at room temperature. At acidic and neutral pH, the pyridinium block of PS-b-P4VP is protonated (PS-b-P4VPH+ pushing CB[7] to preferably host the P4VP block. At basic pH (pH 8, P4VP is not charged and thus is not able to strongly complex CB[7]. This phenomenon was verified further by monitoring the release of pyrene, a hydrophobic cargo model, from a PS-b-P4VPH+/CB[7] micellar membrane. Release study of UV active pyrene from the membrane at different pH values revealed that the system is only operational under basic conditions and that the host-guest interaction of CB[7] with P4VPH+ significantly slows down cargo release.

  3. New dendrimers containing a single cobaltocenium unit covalently attached to the apical position of Newkome dendrons: electrochemistry and guest binding interactions with cucurbit[7]uril.

    Science.gov (United States)

    Sobransingh, David; Kaifer, Angel E

    2006-12-05

    Two new dendrimer series were prepared and characterized. These dendrimers contain a single bis(cyclopentadienyl)cobalt(III) (cobaltocenium, Cob+) unit covalently attached to the apical (focal) position of Newkome-type dendrons, ranging in size from first to third generation. The dendrimers in the first series (1ECob+-3ECob+) are hydrophobic and have 3, 9, and 27 tert-butyl esters on their peripheries, whereas the dendrimers in the second series (1Cob+-3Cob+) are hydrophilic with 3, 9, and 27 carboxylic acid groups on their surfaces, respectively. In voltammetric experiments, all dendrimers showed the expected one-electron reversible reduction of the cobaltocenium center, and the heterogeneous rate of electron transfer decreased with generation in both dendrimer series. The host-guest binding interactions between water-soluble dendrimers 1Cob+-3Cob+ and the cucurbit[7]uril (CB7) host were investigated using 1H NMR spectroscopy, MALDI-TOF mass spectrometry, and electrochemical techniques. The association equilibrium constants (K) for all dendrimer guests were significantly lower than that measured for the inclusion complex between underivatized Cob+ and CB7 (K = 5.7 x 10(9) M(-1)). Nonetheless, among the three dendrimers surveyed, the second-generation dendrimer, 2Cob+, afforded optimum stabilization for the CB7 inclusion complex.

  4. Study of the counter anions in the host-guest chemistry of cucurbit[8]uril and 1-ethyl-1'-benzyl-4,4'-bipyridinium.

    Science.gov (United States)

    Ji, Hailong; Liu, Fengyu; Sun, Shiguo

    2013-01-01

    A series of 1-ethyl-1'-benzyl-4,4'-bipyridinium compounds with different counter anions (BEV-X2, where the X is Cl, Br, I, PF6, ClO4) were synthesized. By using of NMR, MS, electrochemistry, Na2S2O4-induced redox chemistry, and UV-Vis, the role of the different counter anions in the host-guest chemistry of cucurbit[8]uril (CB[8]) was studied for the first time. The result demonstrated that BEV-X2 can form a 1 : 1 host-guest complex with CB[8] in water. Theoretical calculation further suggested that the viologen region was threaded through the cavity of CB[8], while the corresponding counter anions were located outside the cavity. Some difference can be observed on UV-Vis titration and Na2S2O4-induced redox chemistry, which showed that the counter anions have some effect on the host-guest chemistry. All these provide new insights into CB[8] host-guest system.

  5. Preferential molecular encapsulation of an ICT fluorescence probe in the supramolecular cage of cucurbit[7]uril and β-cyclodextrin: an experimental and theoretical approach.

    Science.gov (United States)

    Samanta, Anuva; Guchhait, Nikhil; Bhattacharya, Subhash Chandra

    2014-11-20

    Supramolecular interaction between an intramolecular charge transfer (ICT) probe, N,N-dimethylaminonaphthyl-(acrylo)-nitrile (DMANAN), and two well-recognized macrocyclic hosts, cucurbit[7]uril (CB7) and β-cyclodextrin (β-CD), has been studied in aqueous medium by absorption, emission, time-resolved measurements, and (1)H NMR spectroscopic methods. The changes in the profiles of the fluorescence spectra illustrate significant modifications in fluorescence intensity, decay time, and quantum yield upon confinement of probe within the hydrophobic cavity of the hosts. Using the Benesi-Hildebrand relationship, the stoichiometric ratio as well as the binding constant of the host-guest complexation has been estimated. The stable inclusion complexes of the probe with different hosts have been supported by DFT and ONIOM based quantum chemical calculations. These methods of measurement establish that the acceptor group of the probe resides inside the hydrophobic cavity of the macrocycle. The competitive binding of metal ions and cationic surfactants to CB7 has been excellently mapped with this guest fluorosensor.

  6. The Novel Oomycide Oxathiapiprolin Inhibits All Stages in the Asexual Life Cycle of Pseudoperonospora cubensis - Causal Agent of Cucurbit Downy Mildew.

    Directory of Open Access Journals (Sweden)

    Yigal Cohen

    Full Text Available Oxathiapiprolin is a new oomycide (piperidinyl thiazole isoxazoline class discovered by DuPont which controls diseases caused by oomycete plant pathogens. It binds in the oxysterol-binding protein domain of Oomycetes. Growth chambers studies with detached leaves and potted plants showed remarkable activity of oxathiapiprolin against Pseudoperonospora cubensis in cucurbits. The compound affected all stages in the asexual life cycle of the pathogen. It inhibited zoospore release, cystospore germination, lesion formation, lesion expansion, sporangiophore development and sporangial production. When applied to the foliage as a preventive spray no lesions developed due to inhibition of zoospore release and cystospore germination, and when applied curatively, at one or two days after inoculation, small restricted lesions developed but no sporulation occurred. When applied later to mature lesions, sporulation was strongly inhibited. Oxathiapiprolin suppressed sporulation of P. cubensis in naturally-infected leaves. It exhibited trans-laminar activity, translocated acropetaly from older to younger leaves, and moved from the root system to the foliage. Seed coating was highly effective in protecting the developed cucumber plants against downy mildew. UV microscopy observations made with cucumber leaves infected with P. cubensis revealed that inhibition of mycelium growth and sporulation induced by oxathiapiprolin was associated with callose encasement of the haustoria.

  7. Cell Adhesion on RGD-Displaying Knottins with Varying Numbers of Tryptophan Amino Acids to Tune the Affinity for Assembly on Cucurbit[8]uril Surfaces.

    Science.gov (United States)

    Sankaran, Shrikrishnan; Cavatorta, Emanuela; Huskens, Jurriaan; Jonkheijm, Pascal

    2017-09-05

    Cell adhesion is studied on multivalent knottins, displaying RGD ligands with a high affinity for integrin receptors, that are assembled on CB[8]-methylviologen-modified surfaces. The multivalency in the knottins stems from the number of tryptophan amino acid moieties, between 0 and 4, that can form a heteroternary complex with cucurbit[8]uril (CB[8]) and surface-tethered methylviologen (MV(2+)). The binding affinity of the knottins with CB[8] and MV(2+) surfaces was evaluated using surface plasmon resonance spectroscopy. Specific binding occurred, and the affinity increased with the valency of tryptophans on the knottin. Additionally, increased multilayer formation was observed, attributed to homoternary complex formation between tryptophan residues of different knottins and CB[8]. Thus, we were able to control the surface coverage of the knottins by valency and concentration. Cell experiments with mouse myoblast (C2C12) cells on the self-assembled knottin surfaces showed specific integrin recognition by the RGD-displaying knottins. Moreover, cells were observed to elongate more on the supramolecular knottin surfaces with a higher valency, and in addition, more pronounced focal adhesion formation was observed on the higher-valency knottin surfaces. We attribute this effect to the enhanced coverage and the enhanced affinity of the knottins in their interaction with the CB[8] surface. Collectively, these results are promising for the development of biomaterials including knottins via CB[8] ternary complexes for tunable interactions with cells.

  8. Host-guest complexes of a water soluble cucurbit[6]uril derivative with some dications of 1,ω-alkyldipyridines:~1H NMR and X-ray structures

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Interactions between a symmetrical tetramethyl-substituted cucurbit[6]uril (host:TMeQ[6]) and 1,ω-alkylenedipyridine (ω = 2,4,6,8,10) dicationic guests were investigated using 1H NMR spectroscopy and single crystal X-ray crystallography. In these inclusion complexes,combined cavity and portal binding in TMeQ[6] were observed,and the length of the bridged alkylene was found to play an important role not only in balancing the overall hydrophilic/hydrophobic interaction between the host and the guest,but also in defining the structure of the resulting inclusion complexes. For the guest 1,2-ethylenedipyridine (Edpy),TMeQ[6] includes a positively charged pyridine ring of Edpy to form an unsymmetrical inclusion complex; for the guest 1,4-butylenedipyridine (Bdpy),TMeQ[6] includes a positively charged pyridine ring of Bdpy,but the different competitive interactions in and between the related inclusion complexes could lead to a fast exchange between the hosts and guests. For the guests with longer bridge chains,such as 1,6-hexamethylenedipyridine (Hdpy) or 1,8-octylenedipyridine (Odpy),a stable pseudorotaxane inclusion complex is formed by combining the hydrophobic cavity and the outer portal dipoleion interactions. However,for 1,10-decatylenedipyridine (Ddpy),the two TMeQ[6] host molecules include the two end pyridine rings of Ddpy and form a dumbbell inclusion complex.

  9. Leafing patterns and leaf traits of four evergreen shrubs in the Patagonian Monte, Argentina

    Science.gov (United States)

    Campanella, María Victoria; Bertiller, Mónica B.

    2009-11-01

    We assessed leafing patterns (rate, timing, and duration of leafing) and leaf traits (leaf longevity, leaf mass per area and leaf-chemistry) in four co-occurring evergreen shrubs of the genus Larrea and Chuquiraga (each having two species) in the arid Patagonian Monte of Argentina. We asked whether species with leaves well-defended against water shortage (high LMA, leaf longevity, and lignin concentration, and low N concentration) have lower leaf production, duration of the leafing period, and inter-annual variation of leafing than species with the opposite traits. We observed two distinctive leafing patterns each related to one genus. Chuquiraga species produced new leaves concentrated in a massive short leafing event (5-48 days) while new leaves of Larrea species emerged gradually (128-258 days). Observed leafing patterns were consistent with simultaneous and successive leafing types previously described for woody plants. The peak of leaf production occurred earlier in Chuquiraga species (mid September) than in Larrea species (mid October-late November). Moreover, Chuquiraga species displayed leaves with the longest leaf lifespan, while leaves of Larrea species had the lowest LMA and the highest N and soluble phenolics concentrations. We also observed that only the leaf production of Larrea species increased in humid years. We concluded that co-occurring evergreen species in the Patagonian Monte displayed different leafing patterns, which were associated with some relevant leaf traits acting as plant defenses against water stress and herbivores. Differences in leafing patterns could provide evidence of ecological differentiation among coexisting species of the same life form.

  10. Leaf-produced floral signals.

    Science.gov (United States)

    Zeevaart, Jan A D

    2008-10-01

    Florigen is the hypothetical leaf-produced signal that induces floral initiation at the shoot apex. The nature of florigen has remained elusive for more than 70 years. But recent progress toward understanding the regulatory network for flowering in Arabidopsis has led to the suggestion that FLOWERING LOCUS T (FT) or its product is the mobile flower-inducing signal that moves from an induced leaf through the phloem to the shoot apex. In the past year, physical and chemical evidence has shown that it is FT protein, and not FT mRNA, that moves from induced leaves to the apical meristem. These results have established that FT is the main, if not the only, component of the universal florigen.

  11. Cucurbit[6]uril Modified Silver on the Catalytic Oxidation Property of Dyes%六元瓜环修饰的银对染料的催化氧化性能

    Institute of Scientific and Technical Information of China (English)

    赵安婷; 高丽; 罗娟

    2016-01-01

    Cucurbit[6]uril modified silver was prepared by chemical reduction method using cucurbit[6] uril as the modifier and ascorbic acid as a reducing agent. The structure and morphology of the product were characterized by X-ray diffraction and scanning electron microscope. And its catalytic performance in the oxidation of methylene blue and rhodamine B were studied. The results showed that the silver following the modification had special of clocklike morphology with a diameter of 2 µm when 0.4 mmol cucurbit[6]uril was used. Catalyzed by 0.02 g/L clocklike silver, more than 74.0% of rhodamine-B and 78.0%of methylene blue could be oxidized in 300 min with H2O2.%以六元瓜环(Q[6])为怱饰剂,抗坏血酸为还原剂,采用化学还原法制备了 Q[6]怱饰的银。用X射线粉末衍射、扫描电镜对产物进行结构和形貌表征,并研究了银催化氧化染料次甲基蓝和罗丹明B的性能。结果表明,怱饰剂Q[6]用量为0.4 mmol时,获得的银呈直径为2µm花团状结构,并且对罗丹明B和次甲基蓝具有较好的催化氧化效果,0.02 g/L花团状银在300 min内对罗丹明B和次甲基蓝的脱色率超过74.0%和78.0%。

  12. Caractérisation botanique et agronomique de trois espèces de cucurbites consommées en sauce en Afrique de l'Ouest : Citrullus sp., Cucumeropsis mannii Naudin et Lagenaria siceraria (Molina Standl

    Directory of Open Access Journals (Sweden)

    Zoro Bi I.A.

    2003-01-01

    Full Text Available Botanical and agronomical characterisation of three species of cucurbit consumed as sauce in West Africa: Citrullus sp., Cucumeropsis mannii Naudin and Lagenaria siceraria (Molina Standl. There are in Côte d'Ivoire at least five species of cucurbit incorrectly called ""pistaches"" in town and cultivated at small scale by women for their oleaginous seeds that are a great importance in the sociocultural live of several peoples. Nevertheless, few studies aimed at the improvement of these plants (related notably to taxonomy, genetic resources collecting missions, genetic characterisation, agronomic evaluation, and selection have been carried out. In order to set up a list of reliable traits that should be examined easily during and after collecting missions, we carry out in the present study, for three species (Citrullus sp., Cucumeropsis mannii Naudin and Lagenaria siceraria (Molina Standl a botanic description and an analysis of eleven agronomic traits: 100-seeds weight, germination rate, seedlings emergence time, matured fruit weight, matured fruit decomposition time, mean number of seeds per fruit, seeds shape, fruit diameter, fruit interior cavity diameter, flowering time, and fruiting time. Statistical analyses using nine of these traits showed that the three species can be completely distinguished with six traits whereas the three other traits allowed partial distinction. Low yields have been observed for the three species: 11.41 kg/ha of decorticated seeds for C. mannii, 18.51 kg/ha for Citrullus sp. and 75.14 kg/ha for L. siceraria. From the observed yield components, the possibilities to improve the production of these cucurbits are discussed.

  13. LeafJ: an ImageJ plugin for semi-automated leaf shape measurement.

    Science.gov (United States)

    Maloof, Julin N; Nozue, Kazunari; Mumbach, Maxwell R; Palmer, Christine M

    2013-01-21

    High throughput phenotyping (phenomics) is a powerful tool for linking genes to their functions (see review and recent examples). Leaves are the primary photosynthetic organ, and their size and shape vary developmentally and environmentally within a plant. For these reasons studies on leaf morphology require measurement of multiple parameters from numerous leaves, which is best done by semi-automated phenomics tools. Canopy shade is an important environmental cue that affects plant architecture and life history; the suite of responses is collectively called the shade avoidance syndrome (SAS). Among SAS responses, shade induced leaf petiole elongation and changes in blade area are particularly useful as indices. To date, leaf shape programs (e.g. SHAPE, LAMINA, LeafAnalyzer, LEAFPROCESSOR) can measure leaf outlines and categorize leaf shapes, but can not output petiole length. Lack of large-scale measurement systems of leaf petioles has inhibited phenomics approaches to SAS research. In this paper, we describe a newly developed ImageJ plugin, called LeafJ, which can rapidly measure petiole length and leaf blade parameters of the model plant Arabidopsis thaliana. For the occasional leaf that required manual correction of the petiole/leaf blade boundary we used a touch-screen tablet. Further, leaf cell shape and leaf cell numbers are important determinants of leaf size. Separate from LeafJ we also present a protocol for using a touch-screen tablet for measuring cell shape, area, and size. Our leaf trait measurement system is not limited to shade-avoidance research and will accelerate leaf phenotyping of many mutants and screening plants by leaf phenotyping.

  14. Molecular identification of Cucurbit chlorotic yellow virus in Hainan and Henan province%海南省和河南省发生甜瓜褪绿黄化病的分子鉴定

    Institute of Scientific and Technical Information of China (English)

    刘珊珊; 彭斌; 吴会杰; 柳唐镜; 孔祥义; 施艳; 古勤生

    2013-01-01

    [Objective] To investigate the pathogenic virus causing muskmelon yellowing in Hainan and Henan province, [Methods]the total RNA was extracted from samples collected from infected plants in Sanya, Hainan province and Zhengzhou, Henan province and the coat protein genes(cp) were amplified using Cucurbit cholorotic yellow virus (CCYV) specific primers and cloned. A phylogenetic tree was constructed based on the nucleotide sequences of those cp genes and all the sequences of cp genes within same species and same genus submitted in the GenBank. [Results]The results showed that the fragments of about 880 bp in size produced by RT-PCR were as expected. The phylogenetic tree showed that the samples belonged to the same branch with Cucurbit chlorotic yellow virus whereas Cucuibit yellow stunting disorder virus(CYSDV) and Barley yellow dwarf virus (BPYV) were in other branches. [Conclusions] Our investigation suggested that the yellowing of muskmelon in Hainan and Henan province was caused by Cucurbit cholorotic yellow virus.%[目的]为了探明引起海南省和河南省甜瓜褪绿黄化的病因,[方法]提取从海南三亚和河南郑州采集的甜瓜叶片的RNA,用CCYV特异性引物进行外壳蛋白基因的克隆、测序,并与GenBank中同属或同种病毒的cp基因核苷酸序列构建系统进化树.[结果]结果显示,RT-PCR产物经琼脂糖凝胶电泳,所得条带在880 bp左右,与预期的一致;构建cp基因的系统进化树发现,样品与瓜类褪绿黄化病毒(Cucurbit chlorotic yellows virus,CCYV)的亲缘关系很近,属于同一个分枝,而与该病毒同属不同种的南瓜黄矮失调病毒(Cuc urb it yellow stunting disorder virus,CYSDV)和大麦黄矮病毒(Barley yellow dwarf virus,BYDV)的亲缘关系较远,属于不同的分枝.[结论]证实海南省和河南省甜瓜褪绿黄化病是由瓜类褪绿黄化病毒引起.

  15. In Vitro selectivity of an acyclic cucurbit[n]uril molecular container towards neuromuscular blocking agents relative to commonly used drugs.

    Science.gov (United States)

    Ganapati, Shweta; Zavalij, Peter Y; Eikermann, Matthias; Isaacs, Lyle

    2016-01-28

    An acyclic cucurbit[n]uril (CB[n]) based molecular container (2, a.k.a. Calabadion 2) binds to both amino-steroidal and benzylisoquinolinium type neuromuscular blocking agents (NMBAs) in vitro, and reverses the effect of these drugs in vivo displaying faster recovery times than placebo and the γ-cyclodextrin (CD) based and clinically used reversal agent Sugammadex. In this study we have assessed the potential for other drugs commonly used during and after surgery (e.g. antibiotics, antihistamines, and antiarrhythmics) to interfere with the ability of 2 to bind NMBAs rocuronium and cisatracurium in vitro. We measured the binding affinities (Ka, M(-1)) of twenty seven commonly used drugs towards 2 and simulated the equilibrium between 2, NMBA, and drug based on their standard clinical dosages to calculate the equilibrium concentration of 2·NMBA in the presence of the various drugs. We found that none of the 27 drugs studied possess the combination of a high enough binding affinity with 2 and a high enough standard dosage to be able to promote the competitive dissociation (a.k.a. displacement interactions) of the 2·NMBA complex with the formation of the 2·drug complex. Finally, we used the simulations to explore how the potential for displacement interactions is affected by a number of factors including the Ka of the 2·NMBA complex, the Ka of the AChR·NMBA complex, the Ka of the 2·drug complex, and the dosage of the drug.

  16. A solid-phase microextraction coating of sol-gel-derived perhydroxy cucurbit[6]uril and its application on to the determination of polycyclic aromatic hydrocarbon.

    Science.gov (United States)

    Dong, Nan; Li, Tao; Luo, Yujie; Shao, Lin; Tao, Zhu; Zhu, Chun

    2016-10-28

    A novel solid-phase microextraction coating that contains perhydroxy cucurbit[6]uril((OH)12Q[6]) was prepared by a sol-gel method. (OH)12Q[6] was used as a starting coating material with hydroxy-terminated poly(dimethylsiloxane) (OH-PDMS) to bond chemically to a fused-silica substrate using 3-(2-cyclooxypropoxyl)propyltrimethoxysilane as cross-linking agent; hydrolysis and polycondensation reactions then led to the formation of a (OH)12Q[6]/PDMS-coating. The coating has a high thermal stability (360°C), long lifetime and can withstand organic and inorganic solvent rinsing because of the chemical binding between the coating and silica substrate. Its performance was tested by headspace (HS) solid-phase microextraction fiber coupled with gas chromatography to determine polycyclic aromatic hydrocarbon (PAHs) compounds in water samples. The (OH)12Q[6]/PDMS-coated fiber exhibited higher enrichment factors from fourfold for naphthalene to tenfold for pyrene compared with commercial PDMS fiber, and the enrichment factors increased with the number of condensed PAH rings. The strong adsorption affinity is believed to be attributed to hydrogen bonding and CH⋯π interactions between PAHs and (OH)12Q[6], according to the results of quantum chemical calculations. In the PAH analysis, the (OH)12Q[6]-coated fiber showed a good repeatability (<4.7%) and reproducibility between fibers (<9.4%), low detection limits (0.03-0.15μgL(-1)), and a wide linearity (0.1-1000μgL(-1)) under optimized conditions. This method was used for the simultaneous determination of seven PAHs with satisfactory recoveries of 90.56%-107.4% for Huaxi river water samples and 90.23%-109.5% for local wastewater samples, respectively.

  17. Acyclic Cucurbit[n]uril-Type Molecular Container Enables Systemic Delivery of Effective Doses of Albendazole for Treatment of SK-OV-3 Xenograft Tumors.

    Science.gov (United States)

    Hettiarachchi, Gaya; Samanta, Soumen K; Falcinelli, Shane; Zhang, Ben; Moncelet, Damien; Isaacs, Lyle; Briken, Volker

    2016-03-07

    Approximately, 40-70% of active pharmaceutical ingredients (API) are severely limited by their extremely poor aqueous solubility, and consequently, there is a high demand for excipients that can be used to formulate clinically relevant doses of these drug candidates. Here, proof-of-concept studies demonstrate the potential of our recently discovered acyclic cucurbit[n]uril-type molecular container Motor1 (M1) as a solubilizing agent for insoluble drugs. M1 did not induce significant rates of mutations in various Salmonella typhimurium test strains during the Ames test, suggesting low genotoxicity. M1 also has low risk of causing cardiac toxicity in humans since it did not inhibit the human Ether-à-go-go-Related Gene channel as tested on transfected CHO cell lines via patch clamp analysis. Albendazole (ABZ) is a widely used antihelminthic agent but that has also shown promising efficacy against cancerous cells in vitro. However, due to its low aqueous solubility (2.7 μM) and poor pharmacokinetics, ABZ is clinically limited as an anticancer agent. Here we investigated the potential of M1 as a solubilizing excipient for ABZ formulation. A pharmacokinetic study indicated that ABZ escapes the peritoneal cavity resulting in 78% absolute bioavailability, while its active intermediate metabolite, albendazole sulfoxide, achieved 43% absolute bioavailability. The daily dosing of 681 mg/kg M1 complexed with 3.2 mg/kg of ABZ for 14 days did not result in significant weight loss or pathology in Swiss Webster mice. In vivo efficacy studies using this M1·ABZ inclusion complex showed significant decreases in tumor growth rates and increases in survival of mice bearing SK-OV-3 xenograft tumors. In conclusion, we provide substantial new evidence demonstrating that M1 is a safe and efficient excipient that enables in vivo parenteral delivery of poorly water-soluble APIs.

  18. Separation performance of cucurbit[7]uril in ionic liquid-based sol-gel coating as stationary phase for capillary gas chromatography.

    Science.gov (United States)

    Wang, Xiaogang; Qi, Meiling; Fu, Ruonong

    2014-12-05

    Here we report the separation performance of a new stationary phase of cucurbit[7]uril (CB7) incorporated into an ionic liquid-based sol-gel coating (CB7-SG) for capillary gas chromatography (GC). The CB7-SG stationary phase showed an average polarity of 455, suggesting its polar nature. Abraham system constants revealed that its major interactions with analytes include H-bond basicity (a), dipole-dipole (s) and dispersive (l) interactions. The CB7-SG stationary phase achieved baseline separation for a wide range of analytes with symmetrical peak shapes and showed advantages over the conventional polar stationary phase that failed to resolve some critical analytes. Also, it exhibited different retention behaviors from the conventional stationary phase in terms of retention times and elution order. Most interestingly, in contrast to the conventional polar phase, the CB7-SG stationary phase exhibited longer retentions for analytes of lower polarity but relatively comparable retentions for polar analytes such as alcohols and phenols. The high resolving ability and unique retention behaviors of the CB7-SG stationary phase may stem from the comprehensive interactions of the aforementioned interactions and shape selectivity. Moreover, the CB7-SG column showed good peak shapes for analytes prone to peak tailing, good thermal stability up to 280°C and separation repeatability with RSD values in the range of 0.01-0.11% for intra-day, 0.04-0.41% for inter-day and 2.5-6.0% for column-to-column, respectively. As demonstrated, the proposed coating method can simultaneously address the solubility problem with CBs for the intended purpose and achieve outstanding GC separation performance.

  19. One-Dimensional Coordination Polymers of Lanthanide Cations to Cucurbit[7]uril Built Using a Range of Tetrachloride Transition-Metal Dianion Structure Inducers

    Directory of Open Access Journals (Sweden)

    Sai-Feng Xue

    2013-05-01

    Full Text Available A number of linear coordination polymers have been assembled from lanthanide cations (Ln3+ and cucurbit[7]uril (Q[7] in the presence of [CuCl4]2−or [CoCl4]2− anions acting as inorganic structure inducers in HCl solution. X-ray diffraction analysis has revealed that they form three groups of isomorphous structures. Generally, the complexes of Q[7] with light lanthanide cations (those with atomic number below that of neodymium (Nd3+ are in one group. The other two groups, in which the lanthanide cation has atomic number greater than that of europium (Eu3+, seem to follow no obvious rule. For example, the complexes of Q[7] with Eu3+ and Gd3+cations are in the second group in the presence of [CuCl4]2− anions, while they are in the third group in the presence of [CoCl4]2− anions. However, whatever group a given complex belongs to, they all show a common honeycomb-patterned supramolecular assembly, in which [CuCl4]2−or [CoCl4]2− anions form a honeycomb structure. The Ln3+ cations then coordinate to neighboring Q[7] molecules to form 1D coordination polymers that are inserted into the channels of the honeycomb framework, such that each individual coordination polymer is surrounded by [CuCl4]2−or [CoCl4]2− anions.

  20. Population genomic analyses from low-coverage RAD-Seq data: a case study on the non-model cucurbit bottle gourd.

    Science.gov (United States)

    Xu, Pei; Xu, Shizhong; Wu, Xiaohua; Tao, Ye; Wang, Baogen; Wang, Sha; Qin, Dehui; Lu, Zhongfu; Li, Guojing

    2014-02-01

    Restriction site-associated DNA sequencing (RAD-Seq), a next-generation sequencing-based genome 'complexity reduction' protocol, has been useful in population genomics in species with a reference genome. However, the application of this protocol to natural populations of genomically underinvestigated species, particularly under low-to-medium sequencing depth, has not been well justified. In this study, a Bayesian method was developed for calling genotypes from an F₂ population of bottle gourd [Lagenaria siceraria (Mol.) Standl.] to construct a high-density genetic map. Low-depth genome shotgun sequencing allowed the assembly of scaffolds/contigs comprising approximately 50% of the estimated genome, of which 922 were anchored for identifying syntenic regions between species. RAD-Seq genotyping of a natural population comprising 80 accessions identified 3226 single nuclear polymorphisms (SNPs), based on which two sub-gene pools were suggested for association with fruit shape. The two sub-gene pools were moderately differentiated, as reflected by the Hudson's F(ST) value of 0.14, and they represent regions on LG7 with strikingly elevated F(ST) values. Seven-fold reduction in heterozygosity and two times increase in LD (r²) were observed in the same region for the round-fruited sub-gene pool. Outlier test suggested the locus LX3405 on LG7 to be a candidate site under selection. Comparative genomic analysis revealed that the cucumber genome region syntenic to the high FST island on LG7 harbors an ortholog of the tomato fruit shape gene OVATE. Our results point to a bright future of applying RAD-Seq to population genomic studies for non-model species even under low-to-medium sequencing efforts. The genomic resources provide valuable information for cucurbit genome research.

  1. Hormonal Regulation of Leaf Morphogenesis in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Lin-Chuan Li; Ding-Ming Kang; Zhang-Liang Chen; Li-Jia Qu

    2007-01-01

    Leaf morphogenesis is strictly controlled not only by intrinsic genetic factors, such as transcriptional factors, but also by environmental cues, such as light, water and pathogens. Nevertheless, the molecular mechanism of how leaf rnorphogenesis is regulated by genetic programs and environmental cues is far from clear. Numerous series of events demonstrate that plant hormones, mostly small and simple molecules,play crucial roles in plant growth and development, and in responses of plants to environmental cues such as light. With more and more genetics and molecular evidence obtained from the model plant Arabidopsis,several fundamental aspects of leaf rnorphogenesis including the initiation of leaf primordia, the determination of leaf axes, the regulation of cell division and expansion in leaves have been gradually unveiled.Among these phytohormones, auxin is found to be essential in the regulation of leaf morphogenesis.

  2. Some new and noteworthy diseases of poplars in India. [Botryodiplodia sett-rot; Alternaria tip blight; Cladosporium leaf spot; Fusarium pink incrustation

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S.

    1983-09-01

    Four new diseases of poplars namely Botryodiplodia sett-rott, Alternaria tip blight, Cladosporium leaf spot and Fusarium pink incrustation are described in this paper. Botryodiplodia palmarum causes sett-rott of poplars both at pre-sprouting and post-sprouting stage. The pathogen also causes mortality of poplar plants in the field within 4-6 weeks after planting. Alternaria stage of Pleuspora infectoria has been found as the cause of blackening and dying of growing tips and young leaves of a Populus sp. and P. deltoides in nurseries. Cladosporium humile has been recorded as the cause of brown spot followed by crumpling and premature shedding of leaves in P. ciliata, P. nigra and P. alba. The cause of Fusarium incrustation disease on P. cilata has been identified as Fusarium sp. of Gibbosum group. Pathogenicity of Botryodiplodia palmarum and Alternaria stage of Pleospora infectoria was confirmed by artificial inoculations. Brief descriptions of Alternaria, Cladosporium and Fusarium are also given. The paper also gives a short account of some noteworthy diseases recorded on poplars namely Ganoderma root rot, foliage ruts and stem cankers. Ganoderma root-rot is found to reach alarming proportions in closely spaced poplar plantations. Melampsora ciliata, an indigenous rust, is found to attack mainly clones of P. deltoides, P. yunnanensis, P. trichocarpa, P. alba and some cultivars of P. x euramericana in nurseries. A brief account of three types of stem cankers i.e. cankers due to pink disease fungus, Corticium salmonicolor, sun-scaled cankers and cankers associated with slime flux on various clones of P. deltoides is also given.

  3. Leaf Length Variation in Perennial Forage Grasses

    Directory of Open Access Journals (Sweden)

    Philippe Barre

    2015-08-01

    Full Text Available Leaf length is a key factor in the economic value of different grass species and cultivars in forage production. It is also important for the survival of individual plants within a sward. The objective of this paper is to discuss the basis of within-species variation in leaf length. Selection for leaf length has been highly efficient, with moderate to high narrow sense heritability. Nevertheless, the genetic regulation of leaf length is complex because it involves many genes with small individual effects. This could explain the low stability of QTL found in different studies. Leaf length has a strong response to environmental conditions. However, when significant genotype × environment interactions have been identified, their effects have been smaller than the main effects. Recent modelling-based research suggests that many of the reported environmental effects on leaf length and genotype × environment interactions could be biased. Indeed, it has been shown that leaf length is an emergent property strongly affected by the architectural state of the plant during significant periods prior to leaf emergence. This approach could lead to improved understanding of the factors affecting leaf length, as well as better estimates of the main genetic effects.

  4. Compound leaf development in model plant species.

    Science.gov (United States)

    Bar, Maya; Ori, Naomi

    2015-02-01

    Plant leaves develop in accordance with a common basic program, which is flexibly adjusted to the species, developmental stage and environment. Two key stages of leaf development are morphogenesis and differentiation. In the case of compound leaves, the morphogenesis stage is prolonged as compared to simple leaves, allowing for the initiation of leaflets. Here, we review recent advances in the understanding of how plant hormones and transcriptional regulators modulate compound leaf development, yielding a substantial diversity of leaf forms, focusing on four model compound leaf organisms: cardamine (Cardamine hirsuta), tomato (Solanum lycopersicum), medicago (Medicago truncatula) and pea (Pisum sativum).

  5. Transcriptional networks in leaf senescence.

    Science.gov (United States)

    Schippers, Jos H M

    2015-10-01

    Plant senescence is a natural phenomenon known for the appearance of beautiful autumn colors and the ripening of cereals in the field. Senescence is a controlled process that plants utilize to remobilize nutrients from source leaves to developing tissues. While during the past decades, molecular components underlying the onset of senescence have been intensively studied, knowledge remains scarce on the age-dependent mechanisms that control the onset of senescence. Recent advances have uncovered transcriptional networks regulating the competence to senesce. Here, gene regulatory networks acting as internal timing mechanisms for the onset of senescence are highlighted, illustrating that early and late leaf developmental phases are highly connected.

  6. 7 CFR 28.467 - Leaf Grade 7.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 7. 28.467 Section 28.467 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.467 Leaf Grade 7. Leaf Grade 7 is leaf which is within the range represented...

  7. 7 CFR 28.465 - Leaf Grade 5.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 5. 28.465 Section 28.465 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.465 Leaf Grade 5. Leaf Grade 5 is leaf which is within the range represented...

  8. 7 CFR 28.462 - Leaf Grade 2.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 2. 28.462 Section 28.462 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.462 Leaf Grade 2. Leaf Grade 2 is leaf which is within the range represented...

  9. 7 CFR 28.463 - Leaf Grade 3.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 3. 28.463 Section 28.463 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.463 Leaf Grade 3. Leaf Grade 3 is leaf which is within the range represented...

  10. 7 CFR 28.461 - Leaf Grade 1.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 1. 28.461 Section 28.461 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.461 Leaf Grade 1. Leaf Grade 1 is leaf which is within the range represented...

  11. 7 CFR 28.471 - Below Leaf Grade Cotton.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Below Leaf Grade Cotton. 28.471 Section 28.471... REGULATIONS COTTON CLASSING, TESTING, AND STANDARDS Standards Below Leaf Grade Cotton § 28.471 Below Leaf Grade Cotton. Below leaf grade cotton is American Upland cotton which is lower in leaf grade than...

  12. 7 CFR 28.466 - Leaf Grade 6.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 6. 28.466 Section 28.466 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.466 Leaf Grade 6. Leaf Grade 6 is leaf which is within the range represented...

  13. 7 CFR 28.464 - Leaf Grade 4.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 4. 28.464 Section 28.464 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.464 Leaf Grade 4. Leaf Grade 4 is leaf which is within the range represented...

  14. Sweet pepper confirmed as a reservoir host for tomato yellow leaf curl virus by both agro-inoculation and whitefly-mediated inoculation.

    Science.gov (United States)

    Kil, Eui-Joon; Byun, Hee-Seong; Kim, Sunhoo; Kim, Jaedeok; Park, Jungan; Cho, Seungchan; Yang, Dong-Cheol; Lee, Kyeong-Yeoll; Choi, Hong-Soo; Kim, Ji-Kwang; Lee, Sukchan

    2014-09-01

    Tomato yellow leaf curl virus (TYLCV), a member of the genus Begomovirus, has a single-stranded DNA genome. TYLCV can induce severe disease symptoms on tomato plants, but other hosts plants such as cucurbits and peppers are asymptomatic. A full-length DNA clone of a Korean TYLCV isolate was constructed by rolling-circle amplification from TYLCV-infected tomatoes in Korea. To assess relative susceptibility of sweet pepper varieties to TYLCV, 19 cultivars were inoculated with cloned TYLCV by agro-inoculation. All TYLCV-infected sweet peppers were asymptomatic, even though Southern hybridization and polymerase chain reaction analysis showed TYLCV genomic DNA accumulation in roots, stems, and newly produced shoots. Southern hybridization indicated that TYLCV replicated and moved systemically from agro-inoculated apical shoot tips to roots or newly produced shoots of sweet peppers. Whitefly-mediated inoculation experiments showed that TYLCV can be transmitted to tomatoes from TYLCV-infected sweet peppers. Taken together, these results indicate that sweet pepper can be a reservoir for TYLCV in nature.

  15. Wind-induced leaf transpiration

    Science.gov (United States)

    Huang, Cheng-Wei; Chu, Chia-Ren; Hsieh, Cheng-I.; Palmroth, Sari; Katul, Gabriel G.

    2015-12-01

    While the significance of leaf transpiration (fe) on carbon and water cycling is rarely disputed, conflicting evidence has been reported on how increasing mean wind speed (U) impacts fe from leaves. Here, conditions promoting enhancement or suppression of fe with increasing U for a wide range of environmental conditions are explored numerically using leaf-level gas exchange theories that combine a stomatal conductance model based on optimal water use strategies (maximizing the 'net' carbon gain at a given fe), energy balance considerations, and biochemical demand for CO2. The analysis showed monotonic increases in fe with increasing U at low light levels. However, a decline in modeled fe with increasing U were predicted at high light levels but only in certain instances. The dominant mechanism explaining this decline in modeled fe with increasing U is a shift from evaporative cooling to surface heating at high light levels. New and published sap flow measurements for potted Pachira macrocarpa and Messerschmidia argentea plants conducted in a wind tunnel across a wide range of U (2 - 8 m s-1) and two different soil moisture conditions were also employed to assess how fe varies with increasing U. The radiative forcing imposed in the wind tunnel was only restricted to the lower end of expected field conditions. At this low light regime, the findings from the wind tunnel experiments were consistent with the predicted trends.

  16. "Breath figures" on leaf surfaces-formation and effects of microscopic leaf wetness.

    Science.gov (United States)

    Burkhardt, Juergen; Hunsche, Mauricio

    2013-01-01

    "Microscopic leaf wetness" means minute amounts of persistent liquid water on leaf surfaces which are invisible to the naked eye. The water is mainly maintained by transpired water vapor condensing onto the leaf surface and to attached leaf surface particles. With an estimated average thickness of less than 1 μm, microscopic leaf wetness is about two orders of magnitude thinner than morning dewfall. The most important physical processes which reduce the saturation vapor pressure and promote condensation are cuticular absorption and the deliquescence of hygroscopic leaf surface particles. Deliquescent salts form highly concentrated solutions. Depending on the type and concentration of the dissolved ions, the physicochemical properties of microscopic leaf wetness can be considerably different from those of pure water. Microscopic leaf wetness can form continuous thin layers on hydrophobic leaf surfaces and in specific cases can act similar to surfactants, enabling a strong potential influence on the foliar exchange of ions. Microscopic leaf wetness can also enhance the dissolution, the emission, and the reaction of specific atmospheric trace gases e.g., ammonia, SO2, or ozone, leading to a strong potential role for microscopic leaf wetness in plant/atmosphere interaction. Due to its difficult detection, there is little knowledge about the occurrence and the properties of microscopic leaf wetness. However, based on the existing evidence and on physicochemical reasoning it can be hypothesized that microscopic leaf wetness occurs on almost any plant worldwide and often permanently, and that it significantly influences the exchange processes of the leaf surface with its neighboring compartments, i.e., the plant interior and the atmosphere. The omission of microscopic water in general leaf wetness concepts has caused far-reaching, misleading conclusions in the past.

  17. ‘Breath figures’ on leaf surfaces – formation and effects of microscopic leaf wetness

    Directory of Open Access Journals (Sweden)

    Jürgen eBurkhardt

    2013-10-01

    Full Text Available ‘Microscopic leaf wetness’ means minute amounts of persistent liquid water on leaf surfaces which are invisible to the naked eye. The water is mainly maintained by transpired water vapor condensing onto the leaf surface and to attached leaf surface particles. With an estimated average thickness of less than 1 µm, microscopic leaf wetness it is about 2 orders of magnitude thinner than morning dewfall. The most important physical processes which reduce the saturation vapor pressure and promote condensation are cuticular absorption and the deliquescence of hygroscopic leaf surface particles. Deliquescent salts form highly concentrated solutions. Depending on the amount and concentration of the dissolved ions, the physicochemical properties of microscopic leaf wetness can be considerably different from those of pure water. Microscopic leaf wetness can form continuous thin layers on hydrophobic leaf surfaces and in specific cases can act similar to surfactants, enabling a strong potential influence on the foliar exchange of ions. Microscopic leaf wetness can also enhance the dissolution, the emission, and the reaction of specific atmospheric trace gases e.g. ammonia, SO2, or ozone, leading to a strong potential role for microscopic leaf wetness in plant/atmosphere interaction. Due to its difficult detection, there is little knowledge about the occurrence and the properties of microscopic leaf wetness. However, based on the existing evidence and on physicochemical reasoning it can be hypothesized that microscopic leaf wetness occurs on almost any plant worldwide and often permanently, and that it significantly influences the exchange processes of the leaf surface with its neighboring compartments, i.e., the plant interior and the atmosphere. The omission of microscopic water in general leaf wetness concepts has caused far-reaching, misleading conclusions in the past.

  18. 7 CFR 29.1029 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.1029 Section 29.1029 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 92) § 29.1029 Leaf scrap. A byproduct of stemmed and unstemmed tobacco....

  19. 7 CFR 29.2277 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.2277 Section 29.2277 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... scrap. A byproduct of unstemmed tobacco. Leaf scrap results from handling unstemmed tobacco and...

  20. Leaf out phenology in temperate forests

    Directory of Open Access Journals (Sweden)

    Caroline A. Polgar

    2013-01-01

    Full Text Available Monitoring phenology, the study of the timing of natural events, is an ancient practice that has experienced renewed relevance for scientific research interest in the wake of awareness of anthropogenic climate change. Spring onset has been occurring significantly earlier in temperate regions worldwide. Leaf out phenology has become particularly well studied is of particular interest because the emergence of leaves in the spring is extremely sensitive to temperature, and the leaf out timing of leaf out in temperate ecosystems marks the onset of the growing season and controls many essential ecosystem processes. This article reviews the current literature concerning the different methods used to study leaf out phenology, the controls on leaf out in temperate woody plants, and the effects of climate change on leaf out phenology. In addition to the traditional method of on-the-ground leaf out monitoring, new methods using remote sensing and dedicated cameras have been developed which allow scientists to track spring onset at a much larger scale than hadpreviously been possible. Further work is needed on how leaf phenology will respond to future climate change, and the implications of this for animals and other species interactions among trophic levels.

  1. 7 CFR 30.2 - Leaf tobacco.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf tobacco. 30.2 Section 30.2 Agriculture... Practices), DEPARTMENT OF AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO STOCKS AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of Grades § 30.2...

  2. 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 nu

  3. Leaf Histology--Two Modern Methods.

    Science.gov (United States)

    Freeman, H. E.

    1984-01-01

    Two methods for examining leaf structure are presented; both methods involve use of "superglue." The first method uses the glue to form a thin, permanent, direct replica of a leaf surface on a microscope slide. The second method uses the glue to examine the three-dimensional structure of spongy mesophyll. (JN)

  4. 7 CFR 29.2278 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.2278 Section 29.2278 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... structure. The cell development of a leaf as indicated by its porosity. (See chart, § 29.2351.)...

  5. 7 CFR 29.2530 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.2530 Section 29.2530 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing...-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2530 Leaf structure. The cell development...

  6. Wood and leaf anatomy of Opiliaceae

    NARCIS (Netherlands)

    Koek-Noorman, J.; Rijckevorsel, v. P.

    1983-01-01

    The wood and leaf anatomy of representatives of the 9 genera of the Opiliaceae are described in detail. It is possible to separate the genera on the base of both wood- and leaf anatomical characters. Herein the presence of cystoliths of varying shape and size is important. Some comments on the taxon

  7. Possible Roles of Strigolactones during Leaf Senescence

    Directory of Open Access Journals (Sweden)

    Yusuke Yamada

    2015-09-01

    Full Text Available Leaf senescence is a complicated developmental process that involves degenerative changes and nutrient recycling. The progress of leaf senescence is controlled by various environmental cues and plant hormones, including ethylene, jasmonic acid, salicylic acid, abscisic acid, cytokinins, and strigolactones. The production of strigolactones is induced in response to nitrogen and phosphorous deficiency. Strigolactones also accelerate leaf senescence and regulate shoot branching and root architecture. Leaf senescence is actively promoted in a nutrient-poor soil environment, and nutrients are transported from old leaves to young tissues and seeds. Strigolactones might act as important signals in response to nutrient levels in the rhizosphere. In this review, we discuss the possible roles of strigolactones during leaf senescence.

  8. Inferring climate from angiosperm leaf venation networks.

    Science.gov (United States)

    Blonder, Benjamin; Enquist, Brian J

    2014-10-01

    Leaf venation networks provide an integrative linkage between plant form, function and climate niche, because leaf water transport underlies variation in plant performance. Here, we develop theory based on leaf physiology that uses community-mean vein density to predict growing season temperature and atmospheric CO2 concentration. The key assumption is that leaf water supply is matched to water demand in the local environment. We test model predictions using leaves from 17 temperate and tropical sites that span broad climatic gradients. We find quantitative agreement between predicted and observed climate values. We also highlight additional leaf traits that may improve predictions. Our study provides a novel approach for understanding the functional linkages between functional traits and climate that may improve the reconstruction of paleoclimate from fossil assemblages.

  9. Fontes de resistência em melancia aos principais potyvírus isolados de cucurbitáceas no Nordeste brasileiro

    Directory of Open Access Journals (Sweden)

    Oliveira Vanuzia B. de

    2002-01-01

    Full Text Available A melancia, Citrullus spp., pode ser infetada por várias espécies de vírus, dentre as quais se destacam as pertencentes à família Potyviridae. Visando identificar fontes de resistência a potyvírus, foi iniciado na UFC um programa de indexação do banco de germoplasma de melancia da Embrapa Semi-Árido. Foram utilizadas as espécies de potyvírus, isoladas de cucurbitáceas no Nordeste: Papaya ringspot virus type W (PRSV-W; Watermelon mosaic virus-2 (WMV-2 e Zucchini yellow mosaic virus (ZYMV. Dos 50 acessos de melancia avaliados, 37 pertencem a Citrullus lanatus, 9 a C. lanatus var. citroides e 4 a C. colocynthis. Em casa-de-vegetação foram inoculadas 4 plantas envasadas de cada acesso com PRSV-W, 4 com WMV-2 e 4 com ZYMV, ficando 4 sem inoculação. As inoculações foram efetuadas 8 dias após o plantio, e 15 dias depois. As plantas assintomáticas foram reinoculadas. As plantas que persistiram sem sintomas, após um período de 25 dias após a primeira inoculação, foram testadas por ELISA contra os anti-soros correspondentes. Dentre os acessos avaliados, 5 mostraram-se resistentes aos 3 vírus, um resistente somente ao PRSV-W, 21 resistentes somente ao ZYMV e nenhum com resistência isolada ao WMV-2. No entanto, 45 acessos apresentaram resistência ao ZYMV isoladamente ou em combinação com outro potyvírus. Os acessos suscetíveis, apresentaram sintomas 10 dias após a primeira inoculação enquanto que os resistentes permaneceram sem sintomas após a segunda inoculação e com resultados negativos em ELISA. Alguns acessos poderão ser cruzados visando obter populações segregantes para a seleção de indivíduos homozigotos recessivos e, juntamente com os acessos com resistência tripla identificados, ampliar a variabilidade genética de fontes quanto a características de planta e fruto.

  10. Minimising losses caused by Zucchini yellow mosaic virus in vegetable cucurbit crops in tropical, sub-tropical and Mediterranean environments through cultural methods and host resistance.

    Science.gov (United States)

    Coutts, B A; Kehoe, M A; Jones, R A C

    2011-08-01

    to the existing Integrated Disease Management strategy for ZYMV in vegetable cucurbits in WA, but necessitated modification of its recommendations over deployment of cultivars with resistance genes. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Lipidomics of tobacco leaf and cigarette smoke.

    Science.gov (United States)

    Dunkle, Melissa N; Yoshimura, Yuta; t'Kindt, Ruben; Ortiz, Alexia; Masugi, Eri; Mitsui, Kazuhisa; David, Frank; Sandra, Pat; Sandra, Koen

    2016-03-25

    Detailed lipidomics experiments were performed on the extracts of cured tobacco leaf and of cigarette smoke condensate (CSC) using high-resolution liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (LC-Q-TOF MS). Following automated solid-phase extraction (SPE) fractionation of the lipid extracts, over 350 lipids could be annotated. From a large-scale study on 22 different leaf samples, it was determined that differentiation based on curing type was possible for both the tobacco leaf and the CSC extracts. Lipids responsible for the classification were identified and the findings were correlated to proteomics data acquired from the same tobacco leaf samples. Prediction models were constructed based on the lipid profiles observed in the 22 leaf samples and successfully allowed for curing type classification of new tobacco leaves. A comparison of the leaf and CSC data provided insight into the lipidome changes that occur during the smoking process. It was determined that lipids which survive the smoking process retain the same curing type trends in both the tobacco leaf and CSC data. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Preparation of cucurbit [6] uril anchored silica gel and its adsorption characteristics of sulfamonomethoxine%固载化瓜环的制备及其对磺胺间甲氧嘧啶的吸附性能研究

    Institute of Scientific and Technical Information of China (English)

    靳涛; 陈德强; 刘云; 董元华; 乔洪涛; 陈晓流

    2013-01-01

    在微波无极灯下将烯氧基瓜环固载到巯基硅胶(MSG)上,制得固载化瓜环(ACB[6]-SG).通过红外光谱表征固载产物,并研究固载化瓜环对磺胺间甲氧嘧啶(SMM)的吸附性能.结果表明,SMM在固载化瓜环上的吸附基本在2 min内即可达到平衡;Henry方程和Freundlich方程均能较好地拟合SMM在固载化瓜环和巯基硅胶上的等温吸附曲线,但是SMM在固载化瓜环上的吸附主要是在瓜环中的分配,而SMM在巯基硅胶上的吸附则主要是多分子层的表面吸附作用;SMM在固载化瓜环上的平衡吸附量远大于在巯基硅胶上的平衡吸附量;SMM在两者上的吸附过程是一个放热过程,温度越低吸附效果越好.%Cucurbit [ 6 ] uril anchored silica gel ( ACB [ 6 ] -SG) was produced by anchoring perallyloxy-cucurbit [ 6 ] uril onto 3-mercaptopropyl-functionalized silica gel (MSG) under a microwave electrodeless lamp and was characterized by infrared spectrum analysis. The adsorption behaviors of sulfamonomethoxine (SMM) on ACB[6]-SG and MSG were studied. The results showed that the adsorption of SMM on ACB[6]-SG reached equilibrium in 2 min. The adsorption of SMM on ACB[6]-SG and MSG could be well described by both the Henry model and the Freundlich model. However, the adsorption of SMM on ACB[6]-SG was mainly partition processes of SMM in the cucurbit[6 ] uril, whereas the adsorption of SMM on MSG occurred mainly on the multilayer molecular surface of ACB[6]-SG. Furthermore, the adsorption amount of SMM on ACB[6]-SG at equilibrium was much higher than that on MSG. The adsorption of SMM on both ACB[6]-SG and MSG was an exothermic process, in which the lower the temperature was, the higher the adsorption efficiency.

  13. Leaf dynamics and profitability in wild strawberries.

    Science.gov (United States)

    Jurik, Thomas W; Chabot, Brian F

    1986-05-01

    Leaf dynamics and carbon gain were evaluated for two species of wild strawberry, Fragaria virginiana and F. vesca. Five populations on sites representing a gradient of successional regrowth near Ithaca, N.Y., U.S.A., were studied for two or three years each. A computer-based model of plant growth and CO2 exchange combined field studies of leaf biomass dynamics with previously-determined gas exchange rates to estimate carbon balances of leaves and whole plants in different environments.Leaves were produced throughout the growing season, although there was usually a decline in rate of leaf-production in mid-summer. Leaves produced in late spring had the largest area and longest lifespan (except for overwintering leaves produced in the fall). Specific Leaf Weight (SLW) varied little with time of leaf production, but differed greatly among populations; SLW increased with amount of light received in each habitat. The population in the most open habitat had the least seasonal variation in all leaf characters. F. vesca produced lighter, longer-lived leaves than F. virginiana.Simulations showed that age had the largest effect on leaf carbon gain in high-light environments; water stress and temperature had lesser effects. Leaf carbon gain in lowlight environments was relatively unaffected by age and environmental factors other than light. Leaves in high-light environments had the greatest lifetime profit and the greatest ratio of profit to cost. Increasing lifespan by 1/3 increased profit by 80% in low-light leaves and 50% in high-light leaves. Increasing the number of days during which the leaf had the potential to exhibit high photosynthetic rate in response to high light led to little change in profit of low-light leaves while increasing profit of high-light leaves by 49%.

  14. Global Climatic Controls On Leaf Size

    Science.gov (United States)

    Wright, I. J.; Prentice, I. C.; Dong, N.; Maire, V.

    2015-12-01

    Since the 1890s it's been known that the wet tropics harbour plants with exceptionally large leaves. Yet the observed latitudinal gradient of leaf size has never been fully explained: it is still unclear which aspects of climate are most important for understanding geographic trends in leaf size, a trait that varies many thousand-fold among species. The key is the leaf-to-air temperature difference, which depends on the balance of energy inputs (irradiance) and outputs (transpirational cooling, losses to the night sky). Smaller leaves track air temperatures more closely than larger leaves. Widely cited optimality-based theories predict an advantage for smaller leaves in dry environments, where transpiration is restricted, but are silent on the latitudinal gradient. We aimed to characterize and explain the worldwide pattern of leaf size. Across 7900 species from 651 sites, here we show that: large-leaved species predominate in wet, hot, sunny environments; smaller-leaved species typify hot, sunny environments only when arid; small leaves are required to avoid freezing in high latitudes and at high elevation, and to avoid overheating in dry environments. This simple pattern was unclear in earlier, more limited analyses. We present a simple but robust, fresh approach to energy-balance modelling for both day-time and night-time leaf-to-air temperature differences, and thus risk of overheating and of frost damage. Our analysis shows night-chilling is important as well as day-heating, and simplifies leaf temperature modelling. It provides both a framework for modelling leaf size constraints, and a solution to one of the oldest conundrums in ecology. Although the path forward is not yet fully clear, because of its role in controlling leaf temperatures we suggest that climate-related leaf size constraints could usefully feature in the next generation of land ecosystem models.

  15. Development and application of triple antibody sandwich enzyme-linked immunosorbent assays for begomovirus detection using monoclonal antibodies against Tomato yellow leaf curl Thailand virus.

    Science.gov (United States)

    Seepiban, Channarong; Charoenvilaisiri, Saengsoon; Warin, Nuchnard; Bhunchoth, Anjana; Phironrit, Namthip; Phuangrat, Bencharong; Chatchawankanphanich, Orawan; Attathom, Supat; Gajanandana, Oraprapai

    2017-05-30

    Tomato yellow leaf curl Thailand virus, TYLCTHV, is a begomovirus that causes severe losses of tomato crops in Thailand as well as several countries in Southeast and East Asia. The development of monoclonal antibodies (MAbs) and serological methods for detecting TYLCTHV is essential for epidemiological studies and screening for virus-resistant cultivars. The recombinant coat protein (CP) of TYLCTHV was expressed in Escherichia coli and used to generate MAbs against TYLCTHV through hybridoma technology. The MAbs were characterized and optimized to develop triple antibody sandwich enzyme-linked immunosorbent assays (TAS-ELISAs) for begomovirus detection. The efficiency of TAS-ELISAs for begomovirus detection was evaluated with tomato, pepper, eggplant, okra and cucurbit plants collected from several provinces in Thailand. Molecular identification of begomoviruses in these samples was also performed through PCR and DNA sequence analysis of the CP gene. Two MAbs (M1 and D2) were generated and used to develop TAS-ELISAs for begomovirus detection. The results of begomovirus detection in 147 field samples indicated that MAb M1 reacted with 2 begomovirus species, TYLCTHV and Tobacco leaf curl Yunnan virus (TbLCYnV), whereas MAb D2 reacted with 4 begomovirus species, TYLCTHV, TbLCYnV, Tomato leaf curl New Delhi virus (ToLCNDV) and Squash leaf curl China virus (SLCCNV). Phylogenetic analyses of CP amino acid sequences from these begomoviruses revealed that the CP sequences of begomoviruses recognized by the narrow-spectrum MAb M1 were highly conserved, sharing 93% identity with each other but only 72-81% identity with MAb M1-negative begomoviruses. The CP sequences of begomoviruses recognized by the broad-spectrum MAb D2 demonstrated a wider range of amino acid sequence identity, sharing 78-96% identity with each other and 72-91% identity with those that were not detected by MAb D2. TAS-ELISAs using the narrow-specificity MAb M1 proved highly efficient for the detection of

  16. Leaf-closing substance in Leucaena leucocephala.

    Science.gov (United States)

    Sohtome, Yoshihiro; Tokunaga, Takashi; Ueda, Katsuhiro; Yamamura, Shosuke; Ueda, Minoru

    2002-01-01

    Potassium (2R,3R)-2,3,4-trihydroxy-2-methylbutanoate (1) was identified as a leaf-closing substance in the nyctinastic plant, Leucaena leucocephala. Compound 1 showed strong leaf-closing activity toward L. leucocephala and was not effective against other nyctinastic plants. The potassium ion was indispensable for the bioactivity of 1. Compound 1 gradually lost its bioactivity because of the exchange of the counter cation during isolation. A leaf-opening substance was also observed in the same plant.

  17. Why so strong for the lotus leaf?

    Science.gov (United States)

    Guo, Zhiguang; Liu, Weimin; Su, Bao-Lian

    2008-11-01

    The authors discussed the potential reasons why the lotus leaf is so strong by means of scanning electron microscopy (SEM). The results showed that the good mechanical properties of lotus leaf should be attributed to its architecture, such as paralleled microtubes structure, umbrellalike structure, and hierarchically layered hexagon structure. The important observation from this work is that the surface of the rear face of the lotus leaf seems to be constituted by the layers of hexagons whose hierarchical pilling up of size decreases as we go deeper from surface. This is a typical fractal-like phenomenon.

  18. Antimicrobial activity of Tridax procumbens leaf

    Directory of Open Access Journals (Sweden)

    S.Santhosh Kumar

    2015-03-01

    Full Text Available Estimation of the antimicrobial property of Tridax procumbens’s leaf was carried out by the use of chloroform, petroleum ether, ethyl alcohol and hexaneas solvents. Leaf extract of Tridax procumbens obtained by soxhlet extractor, using the above mentioned solvents were examined against Escherichia coli, Bacillus subtilis, and Pseudomonas vulgaris. The antimicrobial activity of Tridax procumbens performed by using agarwell diffusion method showed a result showcasing an effective limit when as opposed to Pseudomonas vulgarisfor ethyl alcohol being used as solvent for extract. In conclusion Tridax procumbens leaf extract terminates most propitious source.

  19. Control biológico de enfermedades mediante el tratamiento de semillas de cucurbitáceas con rizobacterias promotoras del crecimiento de las plantas (PGPR./Biological control of diseases by cucurbits seeds treatment with rhizobacteria plant growth promoting (PGPR.

    Directory of Open Access Journals (Sweden)

    Gilda Jiménez Montejo

    2014-01-01

    Full Text Available Resumen:Las regulaciones sobre la producción de alimentos sanos limitan actualmente el uso de fungicidas sintéticos para el tratamiento de semillas y, por otra parte, no se dispone de bactericidas efectivos. Se condujeron experimentos en condiciones controladas para evaluar el efecto de las cepas de rizobacterias antagonistas Bacillus subtilis F16/95, B. subtilis Xph y Pseudomonas putida 14A en el control biológico de la Mancha bacteriana de las cucurbitáceas, la Mancha bacteriana del fruto de melón y la pudrición de la raíz, provocadas por Xanthomonas cucurbitae, Acidovorax avenae subsp. citrulli y Fusarium oxysporum, respectivamente. Se realizó el tratamiento de semillas de pepino (C. sativus, L. var. Poinsett, calabaza (Cucurbita moschata, Duch. var. INIVIT C-88, y melón de Castilla (Cucumis melo, L. var. Hale’s Best. Los tratamientos biológicos mostraron una reducción en la incidencia de las enfermedades e incrementos de longitud del tallo y peso fresco de hojas y raíces, en todas las interacciones planta-patógeno-antagonista. La colonización de raíces alcanzó rangos de 8,9-8,0 y 7,8-7,0 log (ufc cm-1 de raíz a los 4 y 15 días después de la siembra. Estos resultados caracterizaron las cepas aplicadas como rizobacterias promotoras del crecimiento vegetal (PGPR y aconsejan la realización de ensayos de campo./Abstract:Nowadays the regulations about the production of healthy foods limit the use of synthetic fungicides for seeds treatment and, on the other hand, effective bactericides are not available. Experiments under controlled conditions were conducted to evaluate the effect of rhizobacterial antagonistic strains Bacillus subtilis F16/95, B. subtilis Xph and Pseudomonas putida 14A on the biological control of Cucurbits bacterial spot, Watermelon bacterial fruit blotch and Fusarium root rot caused by Xanthomonas cucurbitae, Acidovorax avenae subsp. citrulli and Fusarium oxysporum, respectively. Cucumber (Cucumis sativus

  20. The times they are a-changin': seasonal variations of leaf spectra in relation with leaf biochemical and biophysical properties

    Science.gov (United States)

    Yang, X.; Tang, J.; Mustard, J. F.

    2013-12-01

    Leaf traits such as chlorophyll concentration, leaf mass per area (LMA), and mesophyll cell area exposed to the internal area space per leaf area (Ames/A) are key biochemical or biophysical properties to understand the vegetation functioning. Measurements of leaf spectra provided a non-destructive way to estimate those parameters. Many studies have linked leaf spectra with some of leaf traits successfully, but the understanding of spectra-traits relationship is still limited in the following aspects: (1) how does the ability of spectra to estimate leaf traits change (or not) throughout the growing season? (2) How to quantify leaf internal structure with leaf spectra? (3) What are the leaf traits that contribute to the structure parameter in leaf reflectance model such as PROSPECT? To answer the questions above, we conducted weekly measurements of leaf spectra, leaf biochemical properties (chlorophyll, carotenoids, water, and total carbon and nitrogen) and biophysical properties (LMA and internal structures) during the growing seasons of year 2011 and 2012. We found that leaf traits express themselves in the leaf spectra at different wavelengths; the relationships between spectra and leaf traits vary throughout the season. Leaf internal structure parameters are mostly related to the near-infrared reflectance. The structure parameter (N) in PROSPECT is related to the Ames/A, LMA, and water content. Our results have broad implications for using hyperspectral imagers/sensors to monitor vegetations that have clear seasonal patterns.

  1. Evaluation of Methane from Sisal Leaf Residue and Palash Leaf Litter

    Science.gov (United States)

    Arisutha, S.; Baredar, P.; Deshpande, D. M.; Suresh, S.

    2014-12-01

    The aim of this study is to evaluate methane production from sisal leaf residue and palash leaf litter mixed with different bulky materials such as vegetable market waste, hostel kitchen waste and digested biogas slurry in a laboratory scale anaerobic reactor. The mixture was prepared with 1:1 proportion. Maximum methane content of 320 ml/day was observed in the case of sisal leaf residue mixed with vegetable market waste as the feed. Methane content was minimum (47 ml/day), when palash leaf litter was used as feed. This was due to the increased content of lignin and polyphenol in the feedstock which were of complex structure and did not get degraded directly by microorganisms. Sisal leaf residue mixtures also showed highest content of volatile fatty acids (VFAs) as compared to palash leaf litter mixtures. It was observed that VFA concentration in the digester first increased, reached maximum (when pH was minimum) and then decreased.

  2. 7 CFR 30.31 - Classification of leaf tobacco.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Classification of leaf tobacco. 30.31 Section 30.31... REGULATIONS TOBACCO STOCKS AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of Grades § 30.31 Classification of leaf tobacco. For the purpose of this classification leaf tobacco...

  3. 7 CFR 28.517 - Leaf Grade No. 7.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade No. 7. 28.517 Section 28.517 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.517 Leaf Grade No. 7. American Pima cotton which in leaf is inferior to...

  4. 7 CFR 28.514 - Leaf Grade No. 4.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade No. 4. 28.514 Section 28.514 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.514 Leaf Grade No. 4. Leaf grade No. 4 shall be American Pima cotton which...

  5. 7 CFR 28.516 - Leaf Grade No. 6.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade No. 6. 28.516 Section 28.516 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.516 Leaf Grade No. 6. Leaf grade No. 6 shall be American Pima cotton which...

  6. 7 CFR 28.513 - Leaf Grade No. 3.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade No. 3. 28.513 Section 28.513 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.513 Leaf Grade No. 3. Leaf grade No. 3 shall be American Pima cotton which...

  7. 7 CFR 28.515 - Leaf Grade No. 5.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade No. 5. 28.515 Section 28.515 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.515 Leaf Grade No. 5. Leaf grade No. 5 shall be American Pima cotton which...

  8. 7 CFR 28.511 - Leaf Grade No. 1.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade No. 1. 28.511 Section 28.511 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.511 Leaf Grade No. 1. Leaf grade No. 1 shall be American Pima cotton which...

  9. 7 CFR 28.512 - Leaf Grade No. 2.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade No. 2. 28.512 Section 28.512 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.512 Leaf Grade No. 2. Leaf grade No. 2 shall be American Pima cotton which...

  10. What Is a Leaf? An Online Tutorial and Tests

    Science.gov (United States)

    Burrows, Geoffrey

    2008-01-01

    A leaf is a fundamental unit in botany and understanding what constitutes a leaf is fundamental to many plant science activities. My observations and subsequent testing indicated that many students could not confidently and consistently recognise a leaf from a leaflet, or recognise basic leaf arrangements and the various types of compound or…

  11. 7 CFR 29.1162 - Leaf (B Group).

    Science.gov (United States)

    2010-01-01

    .... Uniformity, 70 percent; injury tolerance 30 percent, of which not over 10 percent may be waste. B6L—Poor..., of which not over 10 percent may be waste. B6F—Poor Quality Orange Leaf Ripe, firm leaf structure... percent may be waste. B6FR—Poor Quality Orange Red Leaf Ripe, firm leaf structure, fleshy, lean in...

  12. Monitoring Air Quality with Leaf Yeasts.

    Science.gov (United States)

    Richardson, D. H. S.; And Others

    1985-01-01

    Proposes that leaf yeast serve as quick, inexpensive, and effective techniques for monitoring air quality. Outlines procedures and provides suggestions for data analysis. Includes results from sample school groups who employed this technique. (ML)

  13. Genetic control of leaf curl in maize.

    Science.gov (United States)

    Entringer, G C; Guedes, F L; Oliveira, A A; Nascimento, J P; Souza, J C

    2014-03-17

    Among the many implications of climatic change on agriculture, drought is expected to continue to have a major impact on agribusinesses. Leaf curling is an anatomical characteristic that might be potentially used to enhance plant tolerance to water deficit. Hence, we aimed to study the genetic control of leaf curl in maize. From 2 contrasting inbred lines for the trait, generations F1, F2, and the backcrosses were obtained. All of these generations were evaluated in a randomized block design with 2 replicates. Leaf curl samples were collected from 3 leaves above the first ear at the tasseling stage, and quantified by dividing the width of the leaf blade with natural curling against its extended width. The mean and variance components were estimated by the weighted least square method. It was found that the trait studied has predominance of the additive effects, with genetic control being attributed to few genes that favor selection and exhibit minimal influence from the environment.

  14. Semi-Rolled Leaf2 modulates rice leaf rolling by regulating abaxial side cell differentiation.

    Science.gov (United States)

    Liu, Xiaofei; Li, Ming; Liu, Kai; Tang, Ding; Sun, Mingfa; Li, Yafei; Shen, Yi; Du, Guijie; Cheng, Zhukuan

    2016-04-01

    Moderate leaf rolling maintains the erectness of leaves and minimizes the shadowing between leaves which is helpful to establish ideal plant architecture. Here, we describe asrl2(semi-rolled leaf2) rice mutant, which has incurved leaves due to the presence of defective sclerenchymatous cells on the abaxial side of the leaf and displays narrow leaves and reduced plant height. Map-based cloning revealed that SRL2 encodes a novel plant-specific protein of unknown biochemical function.SRL2 was mainly expressed in the vascular bundles of leaf blades, leaf sheaths, and roots, especially in their sclerenchymatous cells. The transcriptional activities of several leaf development-related YABBY genes were significantly altered in the srl2 mutant. Double mutant analysis suggested that SRL2 and SHALLOT-LIKE1(SLL1)/ROLLED LEAF9(RL9) function in distinct pathways that regulate abaxial-side leaf development. Hence, SRL2 plays an important role in regulating leaf development, particularly during sclerenchymatous cell differentiation. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  15. Characterization of potato leaf starch.

    Science.gov (United States)

    Santacruz, Stalin; Koch, Kristine; Andersson, Roger; Aman, Per

    2004-04-07

    The starch accumulation-degradation process as well as the structure of leaf starch are not completely understood. To study this, starch was isolated from potato leaves collected in the early morning and late afternoon in July and August, representing different starch accumulation rates. The starch content of potato leaves varied between 2.9 and 12.9% (dry matter basis) over the night and day in the middle of July and between 0.6 and 1.5% in August. Scanning electron microscopy analyses of the four isolated starch samples showed that the granules had either an oval or a round shape and did not exceed 5 microm in size. Starch was extracted by successive washing steps with dimethyl sulfoxide and precipitated with ethanol. An elution profile on Sepharose CL-6B of debranched starch showed the presence of a material with a chain length distribution between that generally found for amylose and amylopectin. Amylopectin unit chains of low molecular size were present in a higher amount in the afternoon than in the morning samples. What remains at the end of the night is depleted in specific chain lengths, mainly between DP 15 and 24 and above DP 35, relative to the end of the day.

  16. Research on the modeling method of soybean leafs structure simulation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Leaf is one of the most important organs of soybean. The modeling of soybean leaf structure is useful to research of leaf function. The paper discussed it from two aspects that were distilling method of leaf profile and establishing method of leaf simulation model. It put forward basic method of soybean leaf digital process, and successfully established simulation model of soybean leaf structure based on L-system. It also solved a critical problem in the process of establishing soybean growth simulation model. And the research had guiding significance to establishment of soybean plant model.

  17. Lower Cretaceous angiosperm leaf from Wuhe in Anhui, China

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A new early angiosperm leaf species is reported from the Xinzhuang Formation in Wuhe County, Anhui Province. It is probably of Barremian or slightly later in geological age. The fossil leaf is small, no more than 0.6 cm both in length and in width. The leaf veins are well preserved and clearly visible under a low power microscope. Leaf architectural analysis shows that such a leaf should belong to the first leaf rank of Hickey, I.e. The most primitive one. There are no early angiosperm leaves published completely similar to ours. A new species name of Dicotylophyllum minutissimum sp. Nov. Is established for the present leaf fossils.

  18. Antimicrobial activity of Tridax procumbens leaf

    OpenAIRE

    S. Santhosh Kumar; John, R.; G.Lakshmi Narayanan

    2015-01-01

    Estimation of the antimicrobial property of Tridax procumbens’s leaf was carried out by the use of chloroform, petroleum ether, ethyl alcohol and hexaneas solvents. Leaf extract of Tridax procumbens obtained by soxhlet extractor, using the above mentioned solvents were examined against Escherichia coli, Bacillus subtilis, and Pseudomonas vulgaris. The antimicrobial activity of Tridax procumbens performed by using agarwell diffusion method showed a result showcasing an effective limit when as ...

  19. Wind increases leaf water use efficiency.

    Science.gov (United States)

    Schymanski, Stanislaus J; Or, Dani

    2016-07-01

    A widespread perception is that, with increasing wind speed, transpiration from plant leaves increases. However, evidence suggests that increasing wind speed enhances carbon dioxide (CO2 ) uptake while reducing transpiration because of more efficient convective cooling (under high solar radiation loads). We provide theoretical and experimental evidence that leaf water use efficiency (WUE, carbon uptake per water transpired) commonly increases with increasing wind speed, thus improving plants' ability to conserve water during photosynthesis. Our leaf-scale analysis suggests that the observed global decrease in near-surface wind speeds could have reduced WUE at a magnitude similar to the increase in WUE attributed to global rise in atmospheric CO2 concentrations. However, there is indication that the effect of long-term trends in wind speed on leaf gas exchange may be compensated for by the concurrent reduction in mean leaf sizes. These unintuitive feedbacks between wind, leaf size and water use efficiency call for re-evaluation of the role of wind in plant water relations and potential re-interpretation of temporal and geographic trends in leaf sizes.

  20. Tissue-level leaf toughness, but not lamina thickness, predicts sapling leaf lifespan and shade tolerance of tropical tree species

    NARCIS (Netherlands)

    Kitajima, K.; Poorter, L.

    2010-01-01

    Leaf toughness is thought to enhance physical defense and leaf lifespan. Here, we evaluated the relative importance of tissue-level leaf traits vs lamina thickness, as well as their ontogenetic changes, for structure-level leaf toughness and regeneration ecology of 19 tropical tree species. We

  1. Leaf vein segmentation using Odd Gabor filters and morphological operations

    OpenAIRE

    Katyal, Vini; Aviral

    2012-01-01

    Leaf vein forms the basis of leaf characterization and classification. Different species have different leaf vein patterns. It is seen that leaf vein segmentation will help in maintaining a record of all the leaves according to their specific pattern of veins thus provide an effective way to retrieve and store information regarding various plant species in database as well as provide an effective means to characterize plants on the basis of leaf vein structure which is unique for every specie...

  2. ANALYSIS OF COMPOSITE LEAF SPRING BY USING ANALYTICAL & FEA

    OpenAIRE

    Ranjeet Mithari; Amar Patil; Prof. E. N. Aitavade

    2012-01-01

    Leaf spring are of the oldest suspension component they are still frequently used. The current leaf spring is multiple leaf spring types with a steel material. It has high weight, low natural frequency, high corrosion, more noise. Therefore current multiple leaf spring is replaced by mono composite (E- Glass epoxy) leaf spring which has high natural frequency, low weight etc. The maximum stress produced at the cylindrically joint than fixed joint. Therefore stress analysis of composite materi...

  3. Self-assemblies based on the "outer-surface interactions" of cucurbit[n]urils: new opportunities for supramolecular architectures and materials.

    Science.gov (United States)

    Ni, Xin-Long; Xiao, Xin; Cong, Hang; Zhu, Qian-Jiang; Xue, Sai-Feng; Tao, Zhu

    2014-04-15

    Supramolecular architectures and materials have attracted immense attention during the last decades because they not only open the possibility of obtaining a large variety of aesthetically interesting structures but also have applications in gas storage, sensors, separation, catalysis, and so on. On the other hand, cucurbit[n]urils (Q[n]s), a relatively new class of macrocyclic hosts with a rigid hydrophobic cavity and two identical carbonyl fringed portals, have attracted much attention in supramolecular chemistry. Because of the strong charge-dipole and hydrogen bonding interactions, as well as hydrophobic and hydrophilic effect derived from the negative portals and rigid cavities of Q[n]s, nearly all research in Q[n]s has been focused on utilizing the portals and cavities to construct supramolecular assemblies similar to other macrocyclic receptors such as cyclodextrin and calixarenes. Interestingly, a recent study revealed that other weak noncovalent interactions such as hydrogen bonding and π···π stacking, as well as C-H···π and ion-dipole interactions, could also be defined as "outer-surface interactions", which are derived from the electrostatically positive outer surface of Q[n]s. These interactions could be the driving forces in the formation of various novel Q[n]-based supramolecular architectures and functional materials. In this Account, we provide a comprehensive overview of supramolecular self-assemblies based on the outer-surface interactions of Q[n]s. These outer-surface interactions include those between Q[n]s, Q[n]s and aromatic molecules, Q[n]s and calixarenes, Q[n]s and inorganic complex ions, and Q[n]s and polyoxometalates. Pioneering work has shown that such weak noncovalent interactions play very important roles in the formation of various Q[n]-based functional materials and supramolecular architectures. For example, hydrogen bonds in outer-surface interactions between Q[n] molecules not only function as the sole driving force in the

  4. Barley Leaf Area and Leaf Growth Rates Are Maximized during the Pre-Anthesis Phase

    Directory of Open Access Journals (Sweden)

    Ahmad M. Alqudah

    2015-04-01

    Full Text Available Leaf developmental traits are an important component of crop breeding in small-grain cereals. Surprisingly, little is known about the genetic basis for the differences in barley (Hordeum vulgare L. leaf development. The two barley row-type classes, i.e., two- and six-rowed, show clear-cut differences in leaf development. To quantify these differences and to measure the genetic component of the phenotypic variance for the leaf developmental differences in both row-type classes we investigated 32 representative spring barley accessions (14 two- and 18 six-rowed accessions under three independent growth conditions. Leaf mass area is lower in plants grown under greenhouse (GH conditions due to fewer, smaller, and lighter leaf blades per main culm compared to pot- and soil-grown field plants. Larger and heavier leaf blades of six-rowed barley correlate with higher main culm spike grain yield, spike dry weight, and harvest index; however, smaller leaf area (LA in two-rowed barley can be attributed to more spikes, tillers, and biological yield (aboveground parts. In general, leaf growth rate was significantly higher between awn primordium and tipping stages. Moderate to very high broad-sense heritabilities (0.67–0.90 were found under all growth conditions, indicating that these traits are predominantly genetically controlled. In addition, our data suggests that GH conditions are suitable for studying leaf developmental traits. Our results also demonstrated that LA impacts single plant yield and can be reconsidered in future breeding programs. Six-rowed spike 1 (Vrs1 is the major determinate of barley row-types, the differences in leaf development between two- and six-rowed barleys may be attributed to the regulation of Vrs1 in these two classes, which needs further testing.

  5. Final report on the safety assessment of AloeAndongensis Extract, Aloe Andongensis Leaf Juice,aloe Arborescens Leaf Extract, Aloe Arborescens Leaf Juice, Aloe Arborescens Leaf Protoplasts, Aloe Barbadensis Flower Extract, Aloe Barbadensis Leaf, Aloe Barbadensis Leaf Extract, Aloe Barbadensis Leaf Juice,aloe Barbadensis Leaf Polysaccharides, Aloe Barbadensis Leaf Water, Aloe Ferox Leaf Extract, Aloe Ferox Leaf Juice, and Aloe Ferox Leaf Juice Extract.

    Science.gov (United States)

    2007-01-01

    Plant materials derived from the Aloe plant are used as cosmetic ingredients, including Aloe Andongensis Extract, Aloe Andongensis Leaf Juice, Aloe Arborescens Leaf Extract, Aloe Arborescens Leaf Juice, Aloe Arborescens Leaf Protoplasts, Aloe Barbadensis Flower Extract, Aloe Barbadensis Leaf, Aloe Barbadensis Leaf Extract, Aloe Barbadensis Leaf Juice, Aloe Barbadensis Leaf Polysaccharides, Aloe Barbadensis Leaf Water, Aloe Ferox Leaf Extract, Aloe Ferox Leaf Juice, and Aloe Ferox Leaf Juice Extract. These ingredients function primarily as skin-conditioning agents and are included in cosmetics only at low concentrations. The Aloe leaf consists of the pericyclic cells, found just below the plant's skin, and the inner central area of the leaf, i.e., the gel, which is used for cosmetic products. The pericyclic cells produce a bitter, yellow latex containing a number of anthraquinones, phototoxic compounds that are also gastrointestinal irritants responsible for cathartic effects. The gel contains polysaccharides, which can be acetylated, partially acetylated, or not acetylated. An industry established limit for anthraquinones in aloe-derived material for nonmedicinal use is 50 ppm or lower. Aloe-derived ingredients are used in a wide variety of cosmetic product types at concentrations of raw material that are 0.1% or less, although can be as high as 20%. The concentration of Aloe in the raw material also may vary from 100% to a low of 0.0005%. Oral administration of various anthraquinone components results in a rise in their blood concentrations, wide systemic distribution, accumulation in the liver and kidneys, and excretion in urine and feces; polysaccharide components are distributed systemically and metabolized into smaller molecules. aloe-derived material has fungicidal, antimicrobial, and antiviral activities, and has been effective in wound healing and infection treatment in animals. Aloe barbadensis (also known as Aloe vera)-derived ingredients were not toxic

  6. Between-clone, between-leaf and within-leaf variation in leaf epidermis traits in Iris pumila clones

    Directory of Open Access Journals (Sweden)

    Miljković Danijela

    2013-01-01

    Full Text Available The goal of this study was to analyze variation and covariation in epidermal characteristics (epidermal cell density -ECD, stomata density - SD, and stomata index - SI on Iris pumila clones on between-clone, between-leaf and within-leaf levels. ECD (similar to the pattern previously observed for SD increased from the base to the top of leaf, while SI remained constant. Results of profile analyses indicated that clones, individual plants whitin clones (ramets, and three successive leaves on the same plant were not significantly different for examined characteristics, but genetic variation for position effect was detected (significant Zone x clone interaction. Results of the contrast analysis confirmed differences between the base and middle leaf positions for ECD (similar to those for SD as well as between clone variation for those differences. Observed differences between leaf zones and correlations between analyzed traits were mostly consistent with the expansion hypothesis of stomata differentiation. [Projekat Ministarstva nauke Republike Srbije, br. OI 173025

  7. Global variability in leaf respiration in relation to climate, plant functional types and leaf traits

    NARCIS (Netherlands)

    Atkin, O.; Bloomfield, K.; Reich, P.B.; Tjoelker, M.G.; Asner, G.; Bonal, D.; Bönisch, G.; Poorter, L.

    2015-01-01

    Leaf dark respiration (R-dark) is an important yet poorly quantified component of the global carbon cycle. Given this, we analyzed a new global database of R-dark and associated leaf traits. Data for 899 species were compiled from 100 sites (from the Arctic to the tropics). Several woody and nonwood

  8. NARROW LEAF 7 controls leaf shape mediated by auxin in rice

    NARCIS (Netherlands)

    Fujino, Kenji; Matsuda, Yasuyuki; Ozawa, Kenjirou; Nishimura, Takeshi; Koshiba, Tomokazu; Fraaije, Marco W.; Sekiguchi, Hiroshi

    2008-01-01

    Elucidation of the genetic basis of the control of leaf shape could be of use in the manipulation of crop traits, leading to more stable and increased crop production. To improve our understanding of the process controlling leaf shape, we identified a mutant gene in rice that causes a significant de

  9. Development of leaf area and leaf number of micropropagated potato plants

    NARCIS (Netherlands)

    Tadesse, M.; Lommen, W.J.M.; Putten, van der P.E.L.; Struik, P.C.

    2001-01-01

    Aboveground leaf area and leaf number development of in vitro produced potato plantlets was studied over three growth phases. In vitro plantlets were produced at 17 or 23°C (normalisation phase, 3 weeks), planted in soil at 18/12 or 26/20°C (transplant production phase, 2 weeks), and later transplan

  10. Leaf endophyte load and fungal garden development in leaf-cutting ants

    Science.gov (United States)

    Previous work has shown that leaf-cutting ants prefer to cut leaf material that is relatively low in fungal endophyte content. Such a preference suggests that fungal endophytes exact a cost on the ants or on the development of their colonies. We hypothesized that endophytes may play a role in thei...

  11. Effect of nitrogen supply on leaf growth, leaf nitrogen economy and photosynthetic capacity in potato

    NARCIS (Netherlands)

    Vos, J.; Putten, van der P.E.L.

    1998-01-01

    Literature reports show little effect of nitrogen supply on radiation use efficiency in potato and in other dicotyledonous C3 species. This paper tests the hypothesis that potato reduces leaf size rather than leaf nitrogen concentration and photosynthetic capacity when nitrogen is in short supply. F

  12. MedLeaf: Mobile Application for Medicinal Plant Identification Based on Leaf Image

    Directory of Open Access Journals (Sweden)

    Desta Sandya Prasvita

    2013-01-01

    Full Text Available This research proposes MedLeaf as a new mobile application for medicinal plants identification based on leaf image. The application runs on the Android operating system. MedLeaf has two main functionalities, i.e. medicinal plants identification and document searching of medicinal plant. We used Local Binary Pattern to extract leaf texture and Probabilistic Neural Network to classify the image. In this research, we used30 species of Indonesian medicinal plants and each species consists of 48 digital leaf images. To evaluate user satisfaction of the application we used questionnaire based on heuristic evaluation. The evaluation result shows that MedLeaf is promising for medicinal plants identification. MedLeaf will help botanical garden or natural reserve park management to identify medicinal plant, discover new plant species, plant taxonomy and so on. Also, it will help individual, groups and communities to find unused and undeveloped their skill to optimize the potential of medicinal plants. As the results, MedLeaf will increase of their resources, capitals, and economic wealth.

  13. Venation Skeleton-Based Modeling Plant Leaf Wilting

    Directory of Open Access Journals (Sweden)

    Shenglian Lu

    2009-01-01

    Full Text Available A venation skeleton-driven method for modeling and animating plant leaf wilting is presented. The proposed method includes five principal processes. Firstly, a three-dimensional leaf skeleton is constructed from a leaf image, and the leaf skeleton is further used to generate a detailed mesh for the leaf surface. Then a venation skeleton is generated interactively from the leaf skeleton. Each vein in the venation skeleton consists of a segmented vertices string. Thirdly, each vertex in the leaf mesh is banded to the nearest vertex in the venation skeleton. We then deform the venation skeleton by controlling the movement of each vertex in the venation skeleton by rotating it around a fixed vector. Finally, the leaf mesh is mapped to the deformed venation skeleton, as such the deformation of the mesh follows the deformation of the venation skeleton. The proposed techniques have been applied to simulate plant leaf surface deformation resulted from biological responses of plant wilting.

  14. Maize leaf development under climate change scenarios

    Directory of Open Access Journals (Sweden)

    Nereu Augusto Streck

    2010-11-01

    Full Text Available The objective of this work was to simulate maize leaf development in climate change scenarios at Santa Maria, RS, Brazil, considering symmetric and asymmetric increases in air temperature. The model of Wang & Engel for leaf appearance rate (LAR, with genotype-specific coefficients for the maize variety BRS Missões, was used to simulate tip and expanded leaf accumulated number from emergence to flag leaf appearance and expansion, for nine emergence dates from August 15 to April 15. LAR model was run for each emergence date in 100-year climate scenarios: current climate, and +1, +2, +3, +4 and +5°C increase in mean air temperature, with symmetric and asymmetric increase in daily minimum and maximum air temperature. Maize crop failure due to frost decreased in elevated temperature scenarios, in the very early and very late emergence dates, indicating a lengthening in the maize growing season in warmer climates. The leaf development period in maize was shorter in elevated temperature scenarios, with greater shortening in asymmetric temperature increases, indicating that warmer nights accelerate vegetative development in maize.

  15. Computer vision cracks the leaf code.

    Science.gov (United States)

    Wilf, Peter; Zhang, Shengping; Chikkerur, Sharat; Little, Stefan A; Wing, Scott L; Serre, Thomas

    2016-03-22

    Understanding the extremely variable, complex shape and venation characters of angiosperm leaves is one of the most challenging problems in botany. Machine learning offers opportunities to analyze large numbers of specimens, to discover novel leaf features of angiosperm clades that may have phylogenetic significance, and to use those characters to classify unknowns. Previous computer vision approaches have primarily focused on leaf identification at the species level. It remains an open question whether learning and classification are possible among major evolutionary groups such as families and orders, which usually contain hundreds to thousands of species each and exhibit many times the foliar variation of individual species. Here, we tested whether a computer vision algorithm could use a database of 7,597 leaf images from 2,001 genera to learn features of botanical families and orders, then classify novel images. The images are of cleared leaves, specimens that are chemically bleached, then stained to reveal venation. Machine learning was used to learn a codebook of visual elements representing leaf shape and venation patterns. The resulting automated system learned to classify images into families and orders with a success rate many times greater than chance. Of direct botanical interest, the responses of diagnostic features can be visualized on leaf images as heat maps, which are likely to prompt recognition and evolutionary interpretation of a wealth of novel morphological characters. With assistance from computer vision, leaves are poised to make numerous new contributions to systematic and paleobotanical studies.

  16. A Leaf Recognition Of Vegetables Using Matlab

    Directory of Open Access Journals (Sweden)

    Nadine Jaan D. Caldito

    2015-08-01

    Full Text Available Recognizing plants is a vital problem especially for biologists agricultural researchers and environmentalists. Plant recognition can be performed by human experts manually but it is a time consuming and low-efficiency process. Automation of plant recognition is an important process for the fields working with plants. This paper presents an approach for plant recognition using leaf images. In this study the proponents demonstrated the development of the system that gives users the ability to identify vegetables based on photographs of the leaves taken with a high definition camera. At the heart of this system is a modernize process of identification so as to automate the way of identifying the vegetable plants through leaf image and digital image processing. The system used the Gabor Filter Edge Detection RGB Color and Grayscale Image to acquire the physical parameter of the leaves. The output parameters are used to compute well documented metrics for the statistical and shape. Base on the study the following conclusion are drawn The system can extract the physical parameters from the leafs image that will be used in identifying Vegetables. From the extracted leaf parameters the system provides the statistical analysis and general information of the identified leaf. The used algorithm can organize data and information to useful resources to the future researchers.

  17. Enhancing Accuracy of Plant Leaf Classification Techniques

    Directory of Open Access Journals (Sweden)

    C. S. Sumathi

    2014-03-01

    Full Text Available Plants have become an important source of energy, and are a fundamental piece in the puzzle to solve the problem of global warming. Living beings also depend on plants for their food, hence it is of great importance to know about the plants growing around us and to preserve them. Automatic plant leaf classification is widely researched. This paper investigates the efficiency of learning algorithms of MLP for plant leaf classification. Incremental back propagation, Levenberg–Marquardt and batch propagation learning algorithms are investigated. Plant leaf images are examined using three different Multi-Layer Perceptron (MLP modelling techniques. Back propagation done in batch manner increases the accuracy of plant leaf classification. Results reveal that batch training is faster and more accurate than MLP with incremental training and Levenberg– Marquardt based learning for plant leaf classification. Various levels of semi-batch training used on 9 species of 15 sample each, a total of 135 instances show a roughly linear increase in classification accuracy.

  18. Persimmon leaf flavonoid promotes brain ischemic tolerance**

    Institute of Scientific and Technical Information of China (English)

    Mingsan Miao; Xuexia Zhang; Ming Bai; Linan Wang

    2013-01-01

    Persimmon leaf flavonoid has been shown to enhance brain ischemic tolerance in mice, but its mechanism of action remains unclear. The bilateral common carotid arteries were occluded using a micro clip to block blood flow for 10 minutes. After 10 minutes of ischemic preconditioning, 200, 100, and 50 mg/kg persimmon leaf flavonoid or 20 mg/kg ginaton was intragastrical y administered per day for 5 days. At 1 hour after the final administration, ischemia/reperfusion models were estab-lished by blocking the middle cerebral artery for 2 hours. At 24 hours after model establishment, compared with cerebral ischemic rats without ischemic preconditioning or drug intervention, plasma endothelin, thrombomodulin and von Wil ebrand factor levels significantly decreased and intercel-lular adhesion molecule-1 expression markedly reduced in brain tissue from rats with ischemic pre-conditioning. Simultaneously, brain tissue injury reduced. Ischemic preconditioning combined with drug exposure noticeably improved the effects of the above-mentioned indices, and the effects of 200 mg/kg persimmon leaf flavonoid were similar to 20 mg/kg ginaton treatment. These results indicate that ischemic preconditioning produces tolerance to recurrent severe cerebral ischemia. However, persimmon leaf flavonoid can elevate ischemic tolerance by reducing inflammatory reactions and vascular endothelial injury. High-dose persimmon leaf flavonoid showed an identical effect to ginaton.

  19. ANALYSIS OF COMPOSITE LEAF SPRING BY USING ANALYTICAL & FEA

    Directory of Open Access Journals (Sweden)

    Ranjeet Mithari

    2012-12-01

    Full Text Available Leaf spring are of the oldest suspension component they are still frequently used. The current leaf spring is multiple leaf spring types with a steel material. It has high weight, low natural frequency, high corrosion, more noise. Therefore current multiple leaf spring is replaced by mono composite (E- Glass epoxy leaf spring which has high natural frequency, low weight etc. The maximum stress produced at the cylindrically joint than fixed joint. Therefore stress analysis of composite material mono leaf spring is carried out. The result of finite element method is verified with analytical calculation. Also compare the natural frequency by FFT analyzer with FEA.

  20. Plant Leaf Recognition through Local Discriminative Tangent Space Alignment

    Directory of Open Access Journals (Sweden)

    Chuanlei Zhang

    2016-01-01

    Full Text Available Manifold learning based dimensionality reduction algorithms have been payed much attention in plant leaf recognition as the algorithms can select a subset of effective and efficient discriminative features in the leaf images. In this paper, a dimensionality reduction method based on local discriminative tangent space alignment (LDTSA is introduced for plant leaf recognition based on leaf images. The proposed method can embrace part optimization and whole alignment and encapsulate the geometric and discriminative information into a local patch. The experiments on two plant leaf databases, ICL and Swedish plant leaf datasets, demonstrate the effectiveness and feasibility of the proposed method.

  1. LEAF DISEASE SEVERITY MEASUREMENT USING IMAGE PROCESSING

    Directory of Open Access Journals (Sweden)

    Sanjay B. Patil

    2011-10-01

    Full Text Available Fungi-caused diseases in sugarcane are the most predominant diseases which appear as spots on the leaves. If not treated on time, causes the severe loss. Excessive use of pesticide for plant diseases treatment increases the cost and environmental pollution so their use must be minimized. This can be achieved by targeting the diseases places, with the appropriate quantity and concentration of pesticide by estimating disease severity using image processing technique. Simple threshold and Triangle thresholding methods are used to segment the leaf area and lesion region area respectively. Finally diseases are catcogrise by calculating the quotient of lesion area and leaf area. The accuracy of the experiment is found to be 98.60 %. Research indicates that this method to calculate leaf disease severity is fast and accurate.

  2. Phyllotaxis involves auxin drainage through leaf primordia

    DEFF Research Database (Denmark)

    Deb, Yamini; Marti, Dominik; Frenz, Martin;

    2015-01-01

    of phyllotaxis invoke the accumulation of auxin at leaf initials and removal of auxin through their developing vascular strand, the midvein. We have developed a precise microsurgical tool to ablate the midvein at high spatial and temporal resolution in order to test its function in leaf formation and phyllotaxis...... and to an increase in their width. Phyllotaxis was transiently affected after midvein ablations, but readjusted after two plastochrons. These results indicate that the developing midvein is involved in the basipetal transport of auxin through young primordia, which contributes to phyllotactic spacing and stability...

  3. Leaf water absorption and desorption functions for three turfgrasses

    Science.gov (United States)

    Liang, Xi; Su, Derong; Yin, Shuxia; Wang, Zhi

    2009-09-01

    SummaryPlant leaf can absorb water when the leaf is in contact with water. This happens when the rainfall is intercepted by plant leaves, where the intercepted part of rain remains on the leaf surface. When the intercepted water is either absorbed or subsequently evaporated into the atmosphere, the plant leaves can dissipate water through the desorption process until the plant is dry or rewatered. In this paper, two symptomatic models in the form of exponential functions for leaf water absorption and leaf water desorption were derived and validated by experimental data using leaves of three turfgrasses (Tall fescue, Perennial ryegrass and Kentucky bluegrass). Both the models and measured data showed that the rate of leaf water absorption was high at the low initial leaf water content and then gradually leveled off toward the saturated leaf water content. The rate of leaf water desorption was high at the high initial leaf water content then decreased drastically over time toward zero. The different plant leaves showed different exponents and other parameters of the functions which indicate the difference of plant species. Both the absorption and desorption rates were relatively higher for the Kentucky bluegrass and lower for the Tall fescue and Perennial ryegrass. The concept of specific leaf area ( SLA) was used to understand the saturated leaf water content ( C s) of the three turfgrasses. Linear relationships were found between C s and SLA. The leaf water absorption and desorption functions are useful for deriving physiological parameters of the plant such as permanent wilting leaf water content, naturally irreducible leaf water content, exponential leaf water absorption coefficient, and exponential leaf desorption coefficient, as well as for evaluating the effects of rainfall interception on plant growth and water use efficiency.

  4. Leaf-level nitrogen use efficiency: definition and importance.

    Science.gov (United States)

    Hirose, Tadaki

    2012-07-01

    Nitrogen use efficiency (NUE) has been widely used to study the relationship between nitrogen uptake and dry mass production in the plant. As a subsystem of plant nitrogen use efficiency (NUE), I have defined leaf-level NUE as the surplus production (gross production minus leaf respiration) per unit amount of nitrogen allocated to the leaf, with factorization into leaf nitrogen productivity (NP) and mean residence time of leaf nitrogen (MRT). These concepts were applied to two herbaceous stands: a perennial Solidago altissima stand and an annual Amaranthus patulus stand. S. altissima had more than three times higher leaf NUE than A. patulus due to nearly three times longer MRT of leaf N. In both species, NUE and NP were higher at the leaf level than at the plant level, because most leaf N is involved directly in the photosynthetic activity and because leaf surplus production is higher than the plant net production. MRT was longer at the plant level. The more than twice as long MRT at the plant level as at the leaf level in S. altissima was due to a large contribution of nitrogen storage belowground in the winter in this species. Thus, comparisons between a perennial and an annual system and between plant- and leaf-level NUE with their components revealed the importance of N allocation, storage, recycling, and turnover of organs for leaf photosynthetic production and plant dry mass growth.

  5. 7 CFR 29.3648 - Thin Leaf (C Group).

    Science.gov (United States)

    2010-01-01

    ... Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER... tolerance. C3M Good Quality Mixed Thin Leaf. Mature, thin, firm leaf structure, crepy, oily, normal...

  6. Leaf N and P stoichiometry in relation to leaf shape and plant size for Quercus acutissima provenances across China.

    Science.gov (United States)

    Zhang, Hui; Yang, Xiuqing; Wang, Jingyuan; Wang, G Geoff; Yu, Mukui; Wu, Tonggui

    2017-04-10

    Plant stoichiometry in relation to the structure and function of biological systems has been investigated at multiple scales. However, few studies have focused on the roles of stoichiometry for a given species. In this study, we determined leaf N and P stoichiometry, leaf shape and plant size in three Quercus acutissima common gardens with different climatic and site conditions. In the three common gardens, leaf N and P stoichiometry was significantly correlated with leaf shape and plant size, suggesting that leaf N and P stoichiometry affects the morphological performance of the leaves and stem. The scaling slopes of the relationships between leaf N and P stoichiometry and leaf shape ranged from |0.12| to |1.00|, while the slopes of the relationships between leaf N and P stoichiometry and plant size ranged from |0.95| to |2.66|. These results suggest that non-functional tissues (stem) are more susceptible to leaf nutrition than functional tissues (leaves), and leaf stoichiometry is more important in the construction of non-functional tissues (stem). Between the northernmost and southernmost common gardens, leaf N and leaf width (W), N:P and stem height (H), and N:P and stem diameter (D) showed significant covariations, which indicates that leaf N and W, N:P and plant size exhibit similar plastic responses to environmental change.

  7. The complete genomic sequence of pepper yellow leaf curl virus (PYLCV and its implications for our understanding of evolution dynamics in the genus polerovirus.

    Directory of Open Access Journals (Sweden)

    Aviv Dombrovsky

    Full Text Available We determined the complete sequence and organization of the genome of a putative member of the genus Polerovirus tentatively named Pepper yellow leaf curl virus (PYLCV. PYLCV has a wider host range than Tobacco vein-distorting virus (TVDV and has a close serological relationship with Cucurbit aphid-borne yellows virus (CABYV (both poleroviruses. The extracted viral RNA was subjected to SOLiD next-generation sequence analysis and used as a template for reverse transcription synthesis, which was followed by PCR amplification. The ssRNA genome of PYLCV includes 6,028 nucleotides encoding six open reading frames (ORFs, which is typical of the genus Polerovirus. Comparisons of the deduced amino acid sequences of the PYLCV ORFs 2-4 and ORF5, indicate that there are high levels of similarity between these sequences to ORFs 2-4 of TVDV (84-93% and to ORF5 of CABYV (87%. Both PYLCV and Pepper vein yellowing virus (PeVYV contain sequences that point to a common ancestral polerovirus. The recombination breakpoint which is located at CABYV ORF3, which encodes the viral coat protein (CP, may explain the CABYV-like sequences found in the genomes of the pepper infecting viruses PYLCV and PeVYV. Two additional regions unique to PYLCV (PY1 and PY2 were identified between nucleotides 4,962 and 5,061 (ORF 5 and between positions 5,866 and 6,028 in the 3' NCR. Sequence analysis of the pepper-infecting PeVYV revealed three unique regions (Pe1-Pe3 with no similarity to other members of the genus Polerovirus. Genomic analyses of PYLCV and PeVYV suggest that the speciation of these viruses occurred through putative recombination event(s between poleroviruses co-infecting a common host(s, resulting in the emergence of PYLCV, a novel pathogen with a wider host range.

  8. Breakdown of Leaf Litter in a Neotropical Stream

    OpenAIRE

    Mathuriau, Catherine; Chauvet, Eric

    2002-01-01

    International audience; We investigated the breakdown of 2 leaf species, Croton gossypifolius (Euphorbiaceae) and Clidemia sp. (Melastomataceae), in a 4th-order neotropical stream (Andean Mountains, southwestern Colombia) using leaf bags over a 6-wk period. We determined the initial leaf chemical composition and followed the change in content of organic matter, C, N, and ergosterol, the sporulation activity of aquatic hyphomy cetes, and the structure and composition of leaf-associated aquatic...

  9. Pharmacognostic evaluation of Cayratia trifolia (Linn.) leaf

    Institute of Scientific and Technical Information of China (English)

    Dinesh Kumar; Jyoti Gupta; Sunil Kumar; Renu Arya; Tarun Kumar; Ankit Gupta

    2012-01-01

    Objective: To present a detailed pharmacognostic study of the leaf of Cayratia trifolia (C. trifolia) Linn. (Vitaceae), an important plant in the Indian system of medicine. Methods: The macroscopy, microscopy, physiochemical analysis, preliminary testing, fluorescence analysis of powder of the plant and other WHO recommended methods for standardization were investigated. Results:Leaves are trifoliolated with petioles (2-3 cm) long. Leaflets are ovate to oblong-ovate, (2-8 cm) long, (1.5-5 cm) wide, pointed at the tip. The leaf surface shows the anisocytic type stomata covered with guard cells followed by epidermis layer. Leaf surface contents including veins, vein islet and vein termination were also determined. Transverse section of leaf shows the epidermis layer followed by cuticle layer and vascular bandles (xylem and phloem). The mesophyll is differentiated into palisade and spongy parenchyma. Abundant covering trichomes emerge from the upper epidermis. Trichomes are uniseriate and multicellular. Strips of collenchyma are present below and upper layer of epidermis. Conclusions: It can be concluded that the pharmacognostic profile of the C. trifolia is helpful in developing standards for quality, purity and sample identification.

  10. Comparative leaf anatomy of the Asiatic Myristicaceae

    NARCIS (Netherlands)

    Koster, J.; Baas, P.

    1981-01-01

    The leaf anatomy of c. 60 species of the four Asiatic genera of the Myristicaceae (Gymnacranthera, Horsfieldia, Knema and Myristica) is described in detail. Myristicaceae have characteristic, uniseriate hairs, the cells of which have arms. The number of arms per cell and the relative length of the a

  11. Leaf Stomata as Bioindicators: Stimulating Student Research

    Science.gov (United States)

    Case, Steven B.

    2006-01-01

    Stomata are the pores on leaves through which carbon dioxide, oxygen, and water vapor are exchanged with the atmosphere. Researchers have found that leaf stomatal densities change in response to several environmental variables, including humidity, light intensity, and atmospheric levels of carbon dioxide, a greenhouse gas (Van Der Burgh, Dilcher,…

  12. ACTION OF AUXIN ON LEAF ABSCISSION

    Science.gov (United States)

    Experiments have been conducted to investigate a two-stage effect of auxin on abscission. The two stages were demonstrated on greenhouse-grown Black...the second stage - the stage which is stimulated by auxin . Similar experiments were performed with petioles of various lengths and ages. The...implications of these results indicate possible sites of auxin action on leaf abscission. (Author)

  13. Antioxidant properties of fermented mango leaf extracts.

    Science.gov (United States)

    Park, Anna; Ku, Taekyu; Yoo, Ilsou

    2015-01-01

    Antioxidant properties of mango (Mangifera indica) leaves were evaluated. Hydroalcoholic leaf extracts that were lyophilized were subsequently fermented with either Lactobacillus casei or effective microorganisms (EM) such as probiotic bacteria and/or other anaerobic organisms. Antioxidant properties were measured as a function of the mango leaf extract concentration in the fermentation broth. Tests for radical scavenging using the 1,1-diphenyl-2-picrylhydrazyl radical showed higher antioxidant activity for Lactobacillus- and EM-fermented mango leaf extracts than for the synthetic antioxidant butylated hydroxytoluene. Antioxidant activity generally increased with increasing fermented extract concentration as did the fermented extracts' polyphenol and flavonoid contents. Fermented extracts reduced reactive oxygen species generation by lipopolysaccharide in RAW 264.7 cells when measured via fluorescence of dichlorodihydrofluorescein acetate treated cells using flow cytometry. RAW 264.7 cells also showed a concentration-dependent cytotoxic effect of the fermented extracts using the 3-(4,5-dimethylthialol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Inhibition of mushroom tyrosinase activity as well as nitrite scavenging by the fermented extracts increased as fermented extract concentrations increased. Tyrosinase activity was assayed with 3,4-dihydroxyphenylalanine as substrate. Nitrite scavenging was assessed via measurement of inhibition of chromophore production from nitrite-naphthylamine-sulfanilic acid mixtures. The antioxidant properties of fermented mango leaf extracts suggest the fermented extracts may be useful in developing health food and fermentation-based beauty products.

  14. Leaf habit and woodiness regulate different leaf economy traits at a given nutrient supply

    NARCIS (Netherlands)

    Ordonez, J.C.; Bodegom, van P.M.; Witte, J.P.M.; Bartholomeus, R.P.; Dobben, van H.F.; Aerts, R.

    2010-01-01

    The large variation in the relationships between environmental factors and plant traits observed in natural communities exemplifies the alternative solutions that plants have developed in response to the same environmental limitations. Qualitative attributes, such as growth form, woodiness, and leaf

  15. Macro-detritivore identity drives leaf litter diversity effects

    NARCIS (Netherlands)

    Vos, V.C.A.; Ruijven, van J.; Berg, M.P.; Peeters, E.T.H.M.; Berendse, F.

    2011-01-01

    The importance of leaf litter diversity for decomposition, an important process in terrestrial ecosystems, is much debated. Previous leaf litter-mixing studies have shown that non-additive leaf litter diversity effects can occur, but it is not clear why they occurred in only half of the studies and

  16. 9 CFR 319.702 - Lard, leaf lard.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Lard, leaf lard. 319.702 Section 319... CERTIFICATION DEFINITIONS AND STANDARDS OF IDENTITY OR COMPOSITION Fats, Oils, Shortenings § 319.702 Lard, leaf..., livers, spleens, kidneys, and brains, or settlings and skimmings. “Leaf Lard” is lard prepared from...

  17. 7 CFR 29.1163 - Smoking Leaf (H Group).

    Science.gov (United States)

    2010-01-01

    ... of maturity, more open leaf structure in relation to the B Group, and a material amount of injury characteristic of very ripe leaf tobacco. Grades, Grade Names, Minimum Specifications, and Tolerances H3F—Good... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.1163 Smoking Leaf (H Group). This group consists...

  18. Scaling leaf measurements to estimate cotton canopy gas exchange

    Science.gov (United States)

    Diurnal leaf and canopy gas exchange of well watered field grown cotton were measured. Leaf measurements were made with a portable photosynthesis system and canopy measurements with open Canopy Evapo-Transpiration and Assimilation (CETA) systems. Leaf level measurements were arithmetically scaled to...

  19. Apparent over-investment in leaf venation relaxes leaf morphological constraints on photosynthesis in arid habitats

    Science.gov (United States)

    de Boer, Hugo; Drake, Paul; Veneklaas, Erik

    2017-04-01

    The close relationship between leaf water status and stomatal conductance implies that the hydraulic architecture of leaves poses an important constraint on transpiration, specifically in arid environments with high evaporative demands. However, it remains uncertain how morphological, hydraulic and photosynthetic traits are coordinated to achieve optimal leaf functioning in arid environments. Critical is that leaf veins supply the mesophyll with water that evaporates when stomata are open to allow CO2 uptake for photosynthesis. Theoretical analyses suggest that water is optimally distributed in the mesophyll when the lateral distance between veins (dx) is equal to the distance from these veins to the epidermis (dy), expressed as dx:dy≈1. Although this theory is supported by observations on many derived angiosperms, we hypothesize that plants in arid environments may reduce dx:dy below unity owing to climate-specific functional adaptations of increased leaf thickness and increased vein density. To test our hypothesis we assembled leaf hydraulic, morphological and photosynthetic traits of 68 species from the Eucalyptus and Corymbia genera (termed eucalypts) along an aridity gradient in southwestern Australia. We inferred the potential gas exchange advantage of reducing dx beyond dy using a model that links leaf morphology and hydraulics to photosynthesis. Our observations reveal that eucalypts in arid environments have thick amphistomatous leaves with high vein densities, resulting in dx:dy ratios that range from 1.6 to 0.15 along the aridity gradient. Our model suggests that as leaves become thicker, the effect of reducing dx beyond dy is to offset the reduction in leaf gas exchange that would result from maintaining dx:dy at unity. This apparent over-investment in leaf venation may be explained from the selective pressure of aridity, under which traits associated with long leaf lifespan, high hydraulic and thermal capacitances, and high potential rates of leaf

  20. Does leaf chemistry differentially affect breakdown in tropical versus temperate streams? Importance of standardized analytical techniques to measure leaf chemistry

    Science.gov (United States)

    Marcelo Ardon; Catherine M. Pringle; Susan L. Eggert

    2009-01-01

    Comparisons of the effects of leaf litter chemistry on leaf breakdown rates in tropical vs temperate streams are hindered by incompatibility among studies and across sites of analytical methods used to...

  1. Impact of epidermal leaf mining by the aspen leaf miner (Phyllocnistis populiella) on the growth, physiology, and leaf longevity of quaking aspen.

    Science.gov (United States)

    Wagner, Diane; DeFoliart, Linda; Doak, Patricia; Schneiderheinze, Jenny

    2008-08-01

    The aspen leaf miner, Phyllocnistis populiella, feeds on the contents of epidermal cells on both top (adaxial) and bottom (abaxial) surfaces of quaking aspen leaves, leaving the photosynthetic tissue of the mesophyll intact. This type of feeding is taxonomically restricted to a small subset of leaf mining insects but can cause widespread plant damage during outbreaks. We studied the effect of epidermal mining on aspen growth and physiology during an outbreak of P. populiella in the boreal forest of interior Alaska. Experimental reduction of leaf miner density across two sites and 3 years significantly increased annual aspen growth rates relative to naturally mined controls. Leaf mining damage was negatively related to leaf longevity. Leaves with heavy mining damage abscised 4 weeks earlier, on average, than leaves with minimal mining damage. Mining damage to the top and bottom surfaces of leaves had different effects on physiology. Mining on the top surface of the leaf had no significant effect on photosynthesis or conductance and was unrelated to leaf stable C isotope ratio (delta(13)C). Mining damage to the bottom leaf surface, where stomata are located, had significant negative effects on net photosynthesis and water vapor conductance. Percent bottom mining was positively related to leaf delta(13)C. Taken together, the data suggest that the primary mechanism for the reduction of photosynthesis by epidermal leaf mining by P. populiella is the failure of stomata to open normally on bottom-mined leaves.

  2. Does leaf chemistry differentially affect breakdown in tropical vs temperate streams? Importance of standardized analytical techniques to measure leaf chemistry

    Science.gov (United States)

    Marcelo Ard& #243; n; Catherine M. Pringle; Susan L. Eggert

    2009-01-01

    Comparisons of the effects of leaf litter chemistry on leaf breakdown rates in tropical vs temperate streams are hindered by incompatibility among studies and across sites of analytical methods used to measure leaf chemistry. We used standardized analytical techniques to measure chemistry and breakdown rate of leaves from common riparian tree species at 2 sites, 1...

  3. Simulation of Leaf Area Development Based on Dry Matter Partitioning and Specific Leaf Area for Cut Chrysanthemum

    NARCIS (Netherlands)

    Lee, J.H.; Heuvelink, E.

    2003-01-01

    This work aims to predict time courses of leaf area index (LAI) based on dry matter partitioning into the leaves and on specific leaf area of newly formed leaf biomass (SLA(n)) for year-round cut chrysanthemum crops. In five glasshouse experiments, each consisting of several plant densities and plan

  4. Top predator absence enhances leaf breakdown in an intermittent stream.

    Science.gov (United States)

    Rodríguez-Lozano, Pablo; Rieradevall, Maria; Prat, Narcís

    2016-12-01

    Current biodiversity loss is characterized by the extinction of top predators, but small-bodied freshwater fish are often overlooked in research and conservation management even when threatened because they usually lack commercial value. Therefore, the ecosystem impacts of their possible loss remain mostly unknown. We assessed whether the presence/absence of an endangered predatory fish (Barbus meridionalis (A. Risso, 1827)) in an intermittent stream affects leaf fungal biomass and leaf quality (i.e. leaf carbon:nitrogen ratio and leaf toughness), macroinvertebrate assemblages colonizing leaf packs, and leaf breakdown rates. We conducted a leaf bag experiment comparing a control reach with a population of B. meridionalis with an adjacent upstream fishless reach. In the fishless reach, leaf fungal biomass and microbially mediated breakdown rate were lower compared to the control reach. This was probably caused by the lack of the bottom-up stimulation through nutrient recycling by fish. Shredders and scrapers were found at higher abundance and biomass in the fishless compared to the control reach, and the whole macroinvertebrate community composition changed with fish absence. Consequently, macroinvertebrate mediated leaf breakdown was faster in the fishless than in the control reach, not only compensating for the lower microbially mediated leaf breakdown in the fishless reach, but accelerating the overall leaf breakdown rate. Our study contributes to understand the potential cascading effects produced by the extirpation of endangered small-bodied fish.

  5. The energetic and carbon economic origins of leaf thermoregulation.

    Science.gov (United States)

    Michaletz, Sean T; Weiser, Michael D; McDowell, Nate G; Zhou, Jizhong; Kaspari, Michael; Helliker, Brent R; Enquist, Brian J

    2016-08-22

    Leaf thermoregulation has been documented in a handful of studies, but the generality and origins of this pattern are unclear. We suggest that leaf thermoregulation is widespread in both space and time, and originates from the optimization of leaf traits to maximize leaf carbon gain across and within variable environments. Here we use global data for leaf temperatures, traits and photosynthesis to evaluate predictions from a novel theory of thermoregulation that synthesizes energy budget and carbon economics theories. Our results reveal that variation in leaf temperatures and physiological performance are tightly linked to leaf traits and carbon economics. The theory, parameterized with global averaged leaf traits and microclimate, predicts a moderate level of leaf thermoregulation across a broad air temperature gradient. These predictions are supported by independent data for diverse taxa spanning a global air temperature range of ∼60 °C. Moreover, our theory predicts that net carbon assimilation can be maximized by means of a trade-off between leaf thermal stability and photosynthetic stability. This prediction is supported by globally distributed data for leaf thermal and photosynthetic traits. Our results demonstrate that the temperatures of plant tissues, and not just air, are vital to developing more accurate Earth system models.

  6. The Heat and Mass Transfer Analysis of a Leaf

    Institute of Scientific and Technical Information of China (English)

    Hong Ye; Zhi Yuan; Shuanqin Zhang

    2013-01-01

    Understanding the heat and mass transfer processes of plant leaves is essential for plant bionic engineering.A general thermophysical model was established for a plant leaf with particular emphasis on the transpiration process.The model was verified by the field measured stomatal resistance and temperature of a camphor leaf.A dynamical simulation revealed that diurnal transpiration water consumption is dominated by the solar irradiance and the day-average temperature of the leaf is dominated by the ambient air temperature; transpiration plays an important role in the cooling of the leaf,in average it could dissipate around 32.9% of the total solar energy absorbed by the leaf in summer.To imitate the thermal infared characteristic of the real leaf,the up surface of the bionic leaf must have emissivity and solar absorptivity close to those of a real leaf and its shape and surface roughness must be similar to those of the real leaf.The key point is that the bionic leaf must be able to evaporate water to simulate the transpiration of a plant leaf,appropriate adsorbent can be used to realize this function.

  7. Leaf Vein Extraction Based on Gray-scale Morphology

    Directory of Open Access Journals (Sweden)

    Xiaodong Zheng

    2010-12-01

    Full Text Available Leaf features play an important role in plant species identification and plant taxonomy. The type of the leaf vein is an important morphological feature of the leaf in botany. Leaf vein should be extracted from the leaf in the image before discriminating its type. In this paper a new method of leaf vein extraction has been proposed based on gray-scale morphology. Firstly, the color image of the plant leaf is transformed to the gray image according to the hue and intensity information. Secondly, the gray-scale morphology processing is applied to the image to eliminate the color overlap in the whole leaf vein and the whole background. Thirdly, the linear intensity adjustment is adopted to enlarge the gray value difference between the leaf vein and its background. Fourthly, calculate a threshold with OSTU method to segment the leaf vein from its background. Finally, the leaf vein can be got after some processing on details. Experiments have been conducted with several images. The results show the effectiveness of the method. The idea of the method is also applicable to other linear objects extraction.

  8. Preferência da broca-das-cucurbitáceas [Diaphania nitidalis Cramer, 1782 (Lepidoptera: Pyralidae] por cultivares de pepineiro em ambiente protegido Pickleworm [Diaphania nitidalis Cramer, 1782 (Lepidoptera: Pyralidae]preference for cucumber cultivars in greenhouse

    Directory of Open Access Journals (Sweden)

    Giovani Greigh de Brito

    2004-04-01

    Full Text Available A broca-das-cucurbitáceas (Diaphania nitidalis é uma praga de grande importância em diversas culturas, principalmente do pepineiro. Esta espécie pode apresentar preferência em relação a determinadas cultivares quanto à sua alimentação e até mesmo oviposição. Nesse sentido, o presente estudo objetivou avaliar a ocorrência desta praga em frutos de seis cultivares de pepineiro, em ambiente protegido. As cultivares Patton, Victoria, Premier, Vlaspik e Napoleon apresentaram, respectivamente, 50%, 43,75%, 37,50%, 34,37% e 25,87% dos frutos brocados. A cultivar Marinda apresentou resultado promissor, com apenas 10,37% dos frutos com presença de larvas de D. nitidalis.The pickleworm (Diaphania nitidalis is a major pest on different crops, particulary on cucumber. This species has shown a preference for determined cultivars to its feeding and oviposition habits. Thus, the aim of this study was to evaluate the occurence of D. nitidalis larvae in fruits of six cucumber cultivars in greenhouse. The cultivars Patton, Victoria, Premier, Vlaspik and Napoleon showed, respectively, 50%, 43.75%, 37.50%, 34.37% and 25.87% of bored fruits. Promising results were obtained with the cultivar Marinda, which showed only 10.37% of bored fruits.

  9. Coordination of alkaline earth metal ions in the inverted cucurbit[7]uril supramolecular assemblies formed in the presence of [ZnCl4]2- and [CdCl4]2-.

    Science.gov (United States)

    Li, Qing; Zhang, Yun-Qian; Zhu, Qian-Jiang; Xue, Sai-Feng; Tao, Zhu; Xiao, Xin

    2015-05-01

    A convenient method to isolate inverted cucurbit[7]uril (iQ[7]) from a mixture of water-soluble Q[n]s was established by eluting the soluble mixture of Q[n]s on a Dowex (H(+) form) column so that iQ[7] could be selected as a ligand for coordination and supramolecular assembly with alkaline earth cations (AE(2+)) in aqueous HCl solutions in the presence of [ZnCl(4)](2-) and [CdCl(4)](2-) anions as structure-directing agents. Single-crystal X-ray diffraction analysis revealed that both iQ[7]-AE(2+) -[ZnCl(4)](2-) -HCl and iQ[7]-AE(2+) -[CdCl(4)](2-) -HCl interaction systems yielded supramolecular assemblies, in which the [ZnCl(4)](2-) and [CdCl(4)](2-) anions presented a honeycomb effect, and this resulted in the formation of linear iQ[7]/AE(2+) coordination polymers through outer-surface interactions of Q[n]s.

  10. Antioxidant and α-glucosidase inhibitory activities of cucurbit fruit vegetables and identification of active and major constituents from phenolic-rich extracts of Lagenaria siceraria and Sechium edule.

    Science.gov (United States)

    Sulaiman, Shaida Fariza; Ooi, Kheng Leong; Supriatno

    2013-10-23

    Antioxidant and α-glucosidase activities and total phenolic contents (TPC) in sequential extracts of dried pulps from seven cucurbit fruit vegetables were determined for the first time. The highest TPC and metal chelating activity were obtained from the chloroform extracts of Luffa acutangula (28.04 ± 0.37 mg GAE/g extract) and Benincasa hispida (EC50 = 0.44 ± 0.03 mg/mL), respectively. The ethyl acetate extract of Sechium edule showed the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity (951.73 ± 29.14 mM TE/g extract). The highest reducing and anti-α-glucosidase activities were shown by the methanol and ethyl acetate extracts of Momordica charantia (692.56 ± 43.38 mM AscAE/g extract; 66.64 ± 2.94%, respectively). The highest correlation (r = 0.99) was observed between the TPC and DPPH values of S. edule. Although caffeic acid was quantified as the major constituent in the methanol extract of Lagenaria siceraria , isoquercetin was found to be the main contributor to the activities. Gallic acid was identified as both the main and most active antioxidant constituent in the ethyl acetate extract of S. edule.

  11. Quantitative anatomy of grapevine (Vitis L. leaf blade

    Directory of Open Access Journals (Sweden)

    Valentine S. Codreanu

    2013-04-01

    Full Text Available Current investigations were conducted to clarify the features of grapevine which are adaptive to drought and can be used in selection and introduction of VitisL. There are determined biometric values of 21 morpho-anatomic characters of leaf blade for 10 species of grapevine, 10 cultivars of V. viniferaL. and 10 distant hybrids V. vinifera× Muscadinia rotundifoliaMichx. As a result of this study 6 leaf blade quantitative characters which determine relative grapevine drought resistance were described. The most drought resistant species, sorts and hybrids of grapevine are that which have: a greater average thickness of leaf blade; b smaller surface (average area of leaf blade; c less ratio between average area and average volume of dried leaf blade; d greater mass of dried leaf blade; e higher degrees of the leaf succulence and sclerophylly.

  12. Use of NAP gene to manipulate leaf senescence in plants

    Science.gov (United States)

    Gan, Susheng; Guo, Yongfeng

    2013-04-16

    The present invention discloses transgenic plants having an altered level of NAP protein compared to that of a non-transgenic plant, where the transgenic plants display an altered leaf senescence phenotype relative to a non-transgenic plant, as well as mutant plants comprising an inactivated NAP gene, where mutant plants display a delayed leaf senescence phenotype compared to that of a non-mutant plant. The present invention also discloses methods for delaying leaf senescence in a plant, as well as methods of making a mutant plant having a decreased level of NAP protein compared to that of a non-mutant plant, where the mutant plant displays a delayed leaf senescence phenotype relative to a non-mutant plant. Methods for causing precocious leaf senescence or promoting leaf senescence in a plant are also disclosed. Also disclosed are methods of identifying a candidate plant suitable for breeding that displays a delayed leaf senescence and/or enhanced yield phenotype.

  13. Leaf endophyte load influences fungal garden development in leaf-cutting ants

    Directory of Open Access Journals (Sweden)

    Van Bael Sunshine A

    2012-11-01

    Full Text Available Abstract Background Previous work has shown that leaf-cutting ants prefer to cut leaf material with relatively low fungal endophyte content. This preference suggests that fungal endophytes exact a cost on the ants or on the development of their colonies. We hypothesized that endophytes may play a role in their host plants’ defense against leaf-cutting ants. To measure the long-term cost to the ant colony of fungal endophytes in their forage material, we conducted a 20-week laboratory experiment to measure fungal garden development for colonies that foraged on leaves with low or high endophyte content. Results Colony mass and the fungal garden dry mass did not differ significantly between the low and high endophyte feeding treatments. There was, however, a marginally significant trend toward greater mass of fungal garden per ant worker in the low relative to the high endophyte treatment. This trend was driven by differences in the fungal garden mass per worker from the earliest samples, when leaf-cutting ants had been foraging on low or high endophyte leaf material for only 2 weeks. At two weeks of foraging, the mean fungal garden mass per worker was 77% greater for colonies foraging on leaves with low relative to high endophyte loads. Conclusions Our data suggest that the cost of endophyte presence in ant forage material may be greatest to fungal colony development in its earliest stages, when there are few workers available to forage and to clean leaf material. This coincides with a period of high mortality for incipient colonies in the field. We discuss how the endophyte-leaf-cutter ant interaction may parallel constitutive defenses in plants, whereby endophytes reduce the rate of colony development when its risk of mortality is greatest.

  14. Leaf endophyte load influences fungal garden development in leaf-cutting ants.

    Science.gov (United States)

    Van Bael, Sunshine A; Estrada, Catalina; Rehner, Stephen A; Santos, Janette Fabiola; Wcislo, William T

    2012-11-09

    Previous work has shown that leaf-cutting ants prefer to cut leaf material with relatively low fungal endophyte content. This preference suggests that fungal endophytes exact a cost on the ants or on the development of their colonies. We hypothesized that endophytes may play a role in their host plants' defense against leaf-cutting ants. To measure the long-term cost to the ant colony of fungal endophytes in their forage material, we conducted a 20-week laboratory experiment to measure fungal garden development for colonies that foraged on leaves with low or high endophyte content. Colony mass and the fungal garden dry mass did not differ significantly between the low and high endophyte feeding treatments. There was, however, a marginally significant trend toward greater mass of fungal garden per ant worker in the low relative to the high endophyte treatment. This trend was driven by differences in the fungal garden mass per worker from the earliest samples, when leaf-cutting ants had been foraging on low or high endophyte leaf material for only 2 weeks. At two weeks of foraging, the mean fungal garden mass per worker was 77% greater for colonies foraging on leaves with low relative to high endophyte loads. Our data suggest that the cost of endophyte presence in ant forage material may be greatest to fungal colony development in its earliest stages, when there are few workers available to forage and to clean leaf material. This coincides with a period of high mortality for incipient colonies in the field. We discuss how the endophyte-leaf-cutter ant interaction may parallel constitutive defenses in plants, whereby endophytes reduce the rate of colony development when its risk of mortality is greatest.

  15. A Study of Sugarcane Leaf-Removal Machinery during Harvest

    Directory of Open Access Journals (Sweden)

    Sopa Cansee

    2010-01-01

    Full Text Available Problem statement: Sugarcane leaf-removing tools could help speed up sugarcane harvest and reduce contamination. Moreover, leaf-removal machinery can solve the problems of sugarcane burning and workers can increase sugarcane harvest production too. The purpose of this research was to study the use of leaf-removal machinery in the post-harvest production of sugarcane to reduce harvest production time and contaminant. Approach: This study focused on the LK92-11 variety of sugarcane having a harvesting period of 12 months, a density of 9,387 stems/rai and could produce 14.01 tons/rai including cane top and, leaves and leaf sheaths of 1675.2 and 180 kg/rai. Sugarcane leaf-removal machinery was applied to a small engine power from a grass-cutting machine. A rotate dish applied 4 different materials, tendon string, soft wire, medium wire and sling for sugarcane leaf-removing. The machine was operated at a constant speed. The efficiency of the sugarcane leaf-removal machinery indicated the capacity of sugarcane leaf-removing by area and operation time. Results: The quantity of leaves and leaf sheaths affect the speed of harvest production. Moreover, leaves and leaf sheaths increase the waste material in production and also contaminate the sugar and the sugar production system with clay, sand, and mud from the fields. Traditional methods for sugarcane harvest without removing leaf took 37 h/rai to complete, but sugarcane leaf-removing could reduce the sugarcane harvest process to 11.4 h/rai. Conclusion: The material of the blades in de-leafing machine is crucial to the efficiency of harvest production time. Blades made from poor materials can cause tangling and clogging in the rotator dish, which increases maintenance time. Further developments in sugarcane leaf removal systems will create dramatic improvement in sugarcane production.

  16. Preventing leaf identity theft with hormones.

    Science.gov (United States)

    Lumba, Shelley; McCourt, Peter

    2005-10-01

    Genetic analysis of plant development has begun to demonstrate the importance of hormone synthesis and transport in regulating morphogenesis. In the case of leaf development, for example, auxin pooling determines where a primordium will emerge and leads to the activation of transcription factors, which determine leaf identities by modulating abscisic acid (ABA) and gibberellic acid (GA) concentrations. Signal transduction studies suggest that negative regulation of transcription factors through protein turnover is commonly used as a mechanism of hormone action. Together, these findings suggest that auxin might degrade a repressor that allows the activation of genes that modulate ABA/GA ratios in emerging leaves. With our increased understanding of the molecular basis of hormone signaling, it is becoming possible to overlay important regulators onto signaling modules that determine morphological outputs.

  17. Anatomy of Begonia lucernae Wettst. (Begoniaceae leaf

    Directory of Open Access Journals (Sweden)

    Rodica BERCU

    2015-06-01

    Full Text Available The paper presents anatomical aspects concerning the leaf structure of Begonia lucernae Wettst. belonging to Begoniaceae family. Anatomically, the petiole has a unistratous epidermis and a differentiated mesophyll. The vascular system is fascicular type with a large number of collateral bundles placed into a basic tissue. The lamina is composed of an upper and a lower epidermis and hypodermis as well and the mesophyll. The mesophyll differentiated into palisade tissue and spongy tissue with the same vascular bundle structure such as those of the petiole but with foliar arrangement of the conductive tissues. Stomata are present to the lower epidermis. Paradermal section discloses stright walls epidermal cells and anisocytic stomata. It was calculated the number of stomata/mm2 of leaf surface and the stomatal index as well.

  18. Reference: 82 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available ed as CRUMPLED LEAF (CRL), of Arabidopsis thaliana that affects the morphogenesis of all plant organs and di...protein localized in the outer envelope membrane of plastids affects the pattern of cell division, cell diff

  19. Pectinases in leaf degradation by aquatic Hyphomycetes

    OpenAIRE

    Chamier, Anne-Carole

    1980-01-01

    Packs of oak and alder leaves were submerged in late autumn in the River Bourne, a moderately eutrophic stream in Surrey so that the colonization pattern of aquatic Hyphomycetes on the leaves could be quantified as the leaves were degraded. The physico-chemical of the water was monitored over the experimental period and the inoculum available for leaf colonization was measured by filter counts of conidia in the stream. Colonization of the leaves by pectolytic bacteria was also measured. There...

  20. A survey of GFRP composite leaf spring

    OpenAIRE

    Rajesh, S.; S. Nakkeran; GB. Bhaskar

    2014-01-01

    Although leaf springs are one of the oldest suspension components, they are still frequently used in the automobile vehicles. Weight reduction is the main focus in the automobile industries. Weight reduction can be achieved primarily by the introduction of better materials, design optimization, and better manufacturing processes. The achievement of weight reduction with adequate improvement of mechanical properties has made composite a very good replacement material for conventional steel. Se...

  1. Anatomy of Begonia lucernae Wettst. (Begoniaceae) leaf

    OpenAIRE

    Rodica BERCU

    2015-01-01

    The paper presents anatomical aspects concerning the leaf structure of Begonia lucernae Wettst. belonging to Begoniaceae family. Anatomically, the petiole has a unistratous epidermis and a differentiated mesophyll. The vascular system is fascicular type with a large number of collateral bundles placed into a basic tissue. The lamina is composed of an upper and a lower epidermis and hypodermis as well and the mesophyll. The mesophyll differentiated into palisade tissue and spongy tissue with t...

  2. [Leaf epidermis ultrastructure of Zeugites (Poaceae: Panicoideae)].

    Science.gov (United States)

    Soriano, Ana María; Terrazas, Teresa; Dávila, Patricia

    2011-06-01

    The genus Zeugites comprises eleven species of neotropical grasses and it is principally distributed in Mexico, with some species extending to the Caribbean region, Central and South America. In this work, leaf epidermis ultrastructure of 11 species is described by the use of scanning electron microscopy. At least three specimens per species, that included herbarium and collected specimens, were used. An identification key and specific descriptions are included, in which the distinctive epidermal features are highlighted. The taxonomic valuable characters found were the following: presence or absence of prickles and macrohairs, intercostals short cells form and silica body form. Based on leaf epidermis characteristics, Zeugites species can be arranged into three groups: (1) species that lack prickles (Z. americana, Z. mexicana, Z. pringlei, Z. munroana and Z. sagittata); and lack macro hairs, with the exception of Z. pringlei; (2) species that have prickles (Z. latifolia and Z. smilacifolia); (3) species that have both, prickles and macrohairs (Z. capillaris, Z. hackelii, Z. pittieri and Z. sylvatica). The morphological features of leaf epidermis, support the relationship between the tribes Centotheceae and Paniceae.

  3. Ancient pinnate leaf mimesis among lacewings.

    Science.gov (United States)

    Wang, Yongjie; Liu, Zhiqi; Wang, Xin; Shih, Chungkun; Zhao, Yunyun; Engel, Michael S; Ren, Dong

    2010-09-14

    Insects have evolved diverse methods of predator avoidance, many of which implicate complex adaptations of their wings (e.g., Phylliidae, Nymphalidae, Notodontidae). Among these, angiosperm leaf mimicry is one of the most dramatic, although the historical origins of such modifications are unclear owing to a dearth of paleontological records. Here, we report evidence of pinnate leaf mimesis in two lacewings (Neuroptera): Bellinympha filicifolia Y. Wang, Ren, Liu & Engel gen. et sp. nov. and Bellinympha dancei Y. Wang, Ren, Shih & Engel, sp. nov., from the Middle Jurassic, representing a 165-million-year-old specialization between insects and contemporaneous gymnosperms of the Cycadales or Bennettitales. Furthermore, such lacewings demonstrate a preangiosperm origin for leaf mimesis, revealing a lost evolutionary scenario of interactions between insects and gymnosperms. The current fossil record suggests that this enigmatic lineage became extinct during the Early Cretaceous, apparently closely correlated with the decline of Cycadales and Bennettitales at that time, and perhaps owing to the changing floral environment resulted from the rise of flowering plants.

  4. Inferring Amazon leaf demography from satellite observations of leaf area index

    Directory of Open Access Journals (Sweden)

    S. Caldararu

    2011-10-01

    Full Text Available Seasonal and year-to-year variations in leaf cover imprint significant spatial and temporal variability on biogeochemical cycles, and affect land-surface properties related to climate. We develop a demographic model of leaf phenology based on the hypothesis that trees seek an optimal Leaf Area Index (LAI as a function of available light and soil water, and fitted it to spaceborne observations of LAI over the Amazon Basin, 2001–2005. We find the model reproduces the spatial and temporal LAI distribution whilst also predicting geographic variation in leaf age from the basin center (2.1 ± 0.2 yr, through to the lowest values over the deciduous Eastern Amazon (6 ± 2 months. The model explains the observed increase in LAI during the dry season as a net addition of leaves in response to increased solar radiation. We anticipate our work to be a starting point from which to develop better descriptions of leaf phenology to incorporate into more sophisticated earth system models.

  5. Inferring Amazon leaf demography from satellite observations of leaf area index

    Directory of Open Access Journals (Sweden)

    S. Caldararu

    2012-04-01

    Full Text Available Seasonal and year-to-year variations in leaf cover imprint significant spatial and temporal variability on biogeochemical cycles, and affect land-surface properties related to climate. We develop a demographic model of leaf phenology based on the hypothesis that trees seek an optimal leaf area index (LAI as a function of available light and soil water, and fit it to spaceborne observations of LAI over the Amazon basin, 2001–2005. We find the model reproduces the spatial and temporal LAI distribution whilst also predicting geographic variation in leaf age from the basin centre (2.1 ± 0.2 years, through to the lowest values over the deciduous eastern and southern Amazon (6 ± 2 months. The model explains the observed increase in LAI during the dry season as a net addition of leaves in response to increased solar radiation. We anticipate our work to be a starting point from which to develop better descriptions of leaf phenology to incorporate into more sophisticated earth system models.

  6. Leaf morphological effects predict effective path length and enrichment of 18O in leaf water of different Eucalyptus species

    Science.gov (United States)

    Kahmen, A.; Merchant, A.; Callister, A.; Dawson, T. E.; Arndt, S. K.

    2006-12-01

    Stable isotopes have been a valuable tool to study water or carbon fluxes of plants and ecosystems. In particular oxygen isotopes (δ18O) in leaf water or plant organic material are now beginning to be established as a simple and integrative measure for plant - water relations. Current δ18O models, however, are still limited in their application to a broad range of different species and ecosystems. It remains for example unclear, if species-specific effects such as different leaf morphologies need to be included in the models for a precise understanding and prediction of δ18O signals. In a common garden experiment (Currency Creek Arboretum, South Australia), where over 900 different Eucalyptus species are cultivated in four replicates, we tested effects of leaf morphology and anatomy on δ18O signals in leaf water of 25 different species. In particular, we determined for all species enrichment in 18O of mean lamina leaf water above source water (Δ18O) as related to leaf physiology as well as leaf thickness, leaf area, specific leaf area and weight and selected anatomical properties. Our data revealed that diurnal Δ18O in leaf water at steady state was significantly different among the investigated species and with differences up to 10% at midday. Fitting factors (effective path length) of leaf water Δ18O models were also significantly different among the investigated species and were highly affected by species-specific morphological parameters. For example, leaf area explained a high percentage of the differences in effective path length observed among the investigated species. Our data suggest that leaf water δ18O can act as powerful tool to estimate plant - water relations in comparative studies but that additional leaf morphological parameters need to be considered in existing δ18O models for a better interpretation of the observed δ18O signals.

  7. Photosynthetic responses to leaf surface wetness in tropical plant species of Costa Rica with varying leaf traits

    Science.gov (United States)

    Aparecido, L. M. T.; Moore, G. W.; Miller, G. R.; Cahill, A. T.

    2015-12-01

    Wet tropical forests are some of the environments with the greatest annual precipitation, but are also considered as the world's major carbon sink; however, literature postulates that phothsynthesis rates are inhibited while leaves are wet. Yet measurements of photosynthesis during wet conditions are challenging to obtain due to equipment limitations and the extreme complexity of canopy-atmosphere interactions in tropical environments. The objective of this study was to evaluate tropical species reactions to simulated leaf wetness and test the hypothesis that leaf wetness reduces rates of photosynthesis. In a central Costa Rica site with an average 4200 mm annual rainfall, we selected six tropical species with distinct leaf traits in which five sun-exposed leaf replicates from each species were subjected to gas exchange measurements using a LI-6400 IRGA (LICOR Inc., Lincoln, NE) under dry and wet/misted leaf conditions. Relationships between photosynthesis (As) and stomatal conductance (gs) with leaf to air temperature difference (DT), VPD, and relative humidity were evaluated using linear regression analysis. We found that the responses varied greatly among species, but all plants maintained a baseline of activity under wet leaf conditions, suggesting that abaxial leaf As was a significant percentage of total leaf As. Stachytarpheta jamaicens had an 18.7% reduction in As, while others, like Zamia skinneri, had a 7% increase in As. Tibouchina heteromalla showed a rapid stomatal recovery of 2 mins, while Carapa guianensis was slower with 7 mins. This variability between species suggests that leaf traits, such as presence or absence of trichomes, water repellency, vein distribution and size and leaf angle variation, may be critical for optimizing photosynthesis under wet conditions. Relative humidity and leaf temperature were the strongest secondary influences on As and gs under wet leaf conditions. While tropical vegetation-atmosphere interactions are complex, such

  8. Leaf Morpho–physiology and Leaf-Fe Content of Selected Quince Genotypes from Different Parts of Iran

    Directory of Open Access Journals (Sweden)

    Mitra Mirabdulbaghi

    2014-10-01

    Full Text Available The objectives of this study were to compare genotype variability of leaf morphophysiology and leaf-Fe content, as well as to select quince genotypes possessing desirable characteristics for possible use in breeding projects. Leaves were sampled from 28 quince genotypes that were selected from different parts of Iran. Selected genotypes were grown under the same environmental conditions in nursery of Seed and Plant Improvement Institute. The results suggest that estimated variations of studied leaf chlorophyll fluorescence parameters were slight, but statistically significant. The highest variability was estimated for the leaf area, and somewhat lower for the specific leaf area. The leaves of genotype KM1 had the smallest amount of leaf area and leaf laminar length. Leaf chlorophyll (SPAD-Values and leaf laminar petiole were the highest for the genotype NB2. The genotype SHAI had the highest minimum chlorophyll fluorescence (F0. The highest value of fluorescence variable (FV and chlorophyll fluorescence (FM belonged to Moghavem2. The lowest minimum chlorophyll fluorescence (F0 and the highest value of photochemical capacity of photosystem 2 (FV/FM belonged to the Khosro. The highest amount of leaf laminar width, leaf dry weight and leaf area belonged to sahelborgmoghavem. The leaves of genotype KVD1 had the highest amount of specific leaf area. Simple correlation analysis showed significant negative and positive correlations for some important characteristics. Factor analysis revealed that chlorophyll fluorescence (FM, fluorescence variable (FV, minimum chlorophyll fluorescence (F0 and leaf area were related to the main factor components. Cluster analysis for selective factors divided quince genotypes to five main groups.

  9. Interaction between Silver Nanoparticles and Spinach Leaf

    Science.gov (United States)

    Tian, Y.; Li, H.; Zhang, Y.; Riser, E.; He, S.; Zhang, W.

    2013-12-01

    Interactions of engineered nanoparticles (ENPs) with plant surfaces are critical to assessing the bioavailability of ENPs to edible plants and to further evaluating impacts of ENPs on ecological health and food safety. Silver nanoparticles (i.e., nanoAg) could enter the agroecosystems either as an active ingredient in pesticides or from other industrial and consumer applications. Thus, in the events of pesticide application, rainfall, and irrigation, vegetable leaves could become in contact and then interact with nanoAg. The present study was to assess whether the interaction of nanoAg with spinach leaves can be described by classical sorption models and to what extent it depends on and varies with dispersion methods, environmental temperature, and ion release. We investigated the stability and ion release of nanoAg dispersed by sodium dodecyl sulfate (SDS, 1%) and humic acid (HA, 10 mg C/L) solutions, as well as sorption and desorption of nanoAg on and from the fresh spinach leaf. Results showed SDS-nanoAg released about 2%-8% more Ag ion than HA-nanoAg. The sorption of Ag ion, described by the Freundlich model in the initial concentration range of 0.6-50 mg/L, was 2-4 times higher than that of nanoAg. The sorption of nanoAg on spinach leaf can be fitted by the Langmuir model, and the maximum sorption amount of HA-nanoAg and SDS-nanoAg was 0.21 and 0.41 mg/g, respectively. The higher sorption of SDS-nanoAg relative to that of HA-nanoAg could be partially resulted from the higher release of Ag ion from the former. The maximum desorption amount of HA-nanoAg and SDS-nanoAg in 1% SDS solution was 0.08 and 0.10 mg/g, respectively. NanoAg attachment on and its penetration to the spinach leaf was visualized by the Scanning Electron Microscope equipped with an Energy Dispersive Spectrometer (SEM-EDS). It is equally important that the less sorption of nanoAg under low environmental temperature could be partially due to the closure of stomata, as verified by SEM-EDS. Cyto

  10. A method to improve leaf succulence quantification

    Directory of Open Access Journals (Sweden)

    André Mantovani

    1999-01-01

    Full Text Available Leaf succulence has important physiological and ecological implications. Currently it is quantified by Delf's index (fresh weight/leaf area and fresh weight/ dry weight ratio. Both indeces are reconsidered and a new index is proposed. Shade and sun leaves from terrestrial, hemiepiphytic and epiphytic aroids were studied. Delf's formula, which does not consider dry weight, overestimated leaf succulence. As fresh weight / dry weight ratio (fw / dw does not consider leaf area, plants with the same fw / dw ratio were more than five times different in area. The last case was only possible with a decrease in surface / volume ratio and a increase of mesophyll thickness, components not measured by fw / dw ratio. The new index proposed here, which takes into consideration dry weight and leaf area, showed a high correlation to mesophyll thickness.A suculência foliar tem importantes implicações fisiológicas e ecológicas. Usualmente é quantificada pelo índice de Delf (1912 (peso fresco / area foliar e pela razão peso fresco / peso seco. Estes dois índices são reconsiderados e um novo índice é proposto. Folhas de sombra e sol de aráceas terrestres, hemiepífitas e epífitas foram analisadas. A fórmula de Delf, por não considerar o peso seco das folhas, superestimou a suculência foliar. Como a razão peso fresco / peso seco (pf / ps não leva em consideração a área das folhas, plantas com a mesma razão pf / ps foram mais de cinco vezes diferentes em relação à area foliar. Este último caso só é possível com a redução da razão superfície / volume e com o aumento da espessura do mesofilo, componentes não considerados pela razão pf / ps. O novo índice aqui proposto, que leva em consideração tanto o peso seco das folhas quanto as suas respectivas áreas, mostrou uma alta correlação com a espessura do mesofilo.

  11. Regulation of Leaf Senescence and Crop Genetic Improvement

    Institute of Scientific and Technical Information of China (English)

    Xiao-Yuan Wu; Ben-Ke Kuai; Ji-Zeng Jia; Hai-Chun Jing

    2012-01-01

    Leaf senescence can impact crop production by either changing photosynthesis duration,or by modifying the nutrient remobilization efficiency and harvest index.The doubling of the grain yield in major cereals in the last 50 years was primarily achieved through the extension of photosynthesis duration and the increase in crop biomass partitioning,two things that are intrinsically coupled with leaf senescence.In this review,we consider the functionality of a leaf as a function of leaf age,and divide a leaf's life into three phases:the functionality increasing phase at the early growth stage,the full functionality phase,and the senescence and functionality decreasing phase.A genetic framework is proposed to describe gene actions at various checkpoints to regulate leaf development and senescence.Four categories of genes contribute to crop production:those which regulate (Ⅰ) the speed and transition of early leaf growth,(Ⅱ) photosynthesis rate,(Ⅲ) the onset and (Ⅳ) the progression of leaf senescence.Current advances in isolating and characterizing senescence regulatory genes are discussed in the leaf aging and crop production context.We argue that the breeding of crops with leaf senescence ideotypes should be an essential part of further crop genetic improvement.

  12. Ginseng leaf-stem: bioactive constituents and pharmacological functions

    Directory of Open Access Journals (Sweden)

    Xie Jingtian

    2009-10-01

    Full Text Available Abstract Ginseng root is used more often than other parts such as leaf stem although extracts from ginseng leaf-stem also contain similar active ingredients with pharmacological functions. Ginseng's leaf-stems are more readily available at a lower cost than its root. This article reviews the pharmacological effects of ginseng leaf-stem on some diseases and adverse effects due to excessive consumption. Ginseng leaf-stem extract contains numerous active ingredients, such as ginsenosides, polysaccharides, triterpenoids, flavonoids, volatile oils, polyacetylenic alcohols, peptides, amino acids and fatty acids. The extract contains larger amounts of the same active ingredients than the root. These active ingredients produce multifaceted pharmacological effects on the central nervous system, as well as on the cardiovascular, reproductive and metabolic systems. Ginseng leaf-stem extract also has anti-fatigue, anti-hyperglycemic, anti-obesity, anti-cancer, anti-oxidant and anti-aging properties. In normal use, ginseng leaf-stem extract is quite safe; adverse effects occur only when it is over dosed or is of poor quality. Extracts from ginseng root and leaf-stem have similar multifaceted pharmacological activities (for example central nervous and cardiovascular systems. In terms of costs and source availability, however, ginseng leaf-stem has advantages over its root. Further research will facilitate a wider use of ginseng leaf-stem.

  13. Experimental Investigation on Laminated Composite Leaf springs Subjected to Cyclic Loading

    OpenAIRE

    Rajesh, S.; G.B.Bhaskar

    2014-01-01

    An automobile industry have an interest in replacement of conventional leaf spring with composite leaf spring to get better performance with less weight. This paper deals with by replacing the conventional leaf spring with composite leaf spring. The dimensions of an existing conventional steel leaf spring of a light commercial vehicle were taken to fabricate the special die which is further used to manufacture the composite leaf spring. A single leaf with constant cross sectional area similar...

  14. Relationship of 2 100-2 300 nm Spectral Characteristics of Wheat Canopy to Leaf Area Index and Leaf N as Affected by Leaf Water Content

    Institute of Scientific and Technical Information of China (English)

    ZHAO Chun-Jiang; WANG Ji-Hua; LIU Liang-Yun; HUANG Wen-Jiang; ZHOU Qi-Fa

    2006-01-01

    The effects of leaf water status in a wheat canopy on the accuracy of estimating leaf area index (LAI) and N were determined in this study using extracted spectral characteristics in the 2 000-2 300 nm region of the short wave infrared (SWI) band. A newly defined spectral index, relative adsorptive index in the 2 000-2 300 nm region (RAI2000-2300), which can be calculated by RAI2000-2300 = (R2224 - R2054) (R2224 + R2054)-1 with R being the reflectance at 2 224 or2 054 nm, was utilized. This spectral index, RAI2000-2300, was significantly correlated (P < 0.01) with green LAI and leaf N concentration and proved to be potentially valuable for monitoring plant green LAI and leaf N at the field canopy scale. Moreover, plant LAI could be monitored more easily and more successfully than plant leaf N. The study also showed that leaf water had a strong masking effect on the 2 000-2 300 nm spectral characteristics and both the coefficient between RAI2000-2300 and green LAI and that between RAI2000-2300 and leaf N content decreased as leaf water content increased.

  15. Quantitative trait loci mapping for leaf length and leaf width in rice cv. IR64 derived lines.

    Science.gov (United States)

    Farooq, Muhammad; Tagle, Analiza G; Santos, Rizza E; Ebron, Leodegario A; Fujita, Daisuke; Kobayashi, Nobuya

    2010-06-01

    The present study was conducted to identify quantitative trait loci (QTLs) for leaf size traits in IR64 introgression lines (INLs). For this purpose, selected F(2) populations derived from crosses between recurrent parent IR64 and its derived INLs, unique for leaf length and leaf width, were used to confirm QTLs. A total of eight QTLs, mapped on three chromosomes, were identified for the four leaf size traits in six F(2) populations. A QTL for leaf length, qLLnpt-1, in HKL69 was identified around simple sequence repeat (SSR) marker RM3709 on chromosome 1. Two QTLs for flag leaf length, qFLLnpt-2 and qFLLnpt-4, in HFG39 were indentified on chromosomes 2 and 4, respectively. For flag leaf width, a QTL, qFLWnpt-4, in HFG39 was identified around RM17483 on chromosome 4. While another QTL for flag leaf width, qFLWnpt-1, in HFG27 was identified around RM3252 on chromosome 1. A QTL for leaf width, qLWnpt-2, in HKL75 was identified around RM7451 on chromosome 2. For leaf width, two QTLs, qLWnpt-4a, qLWnpt-4b, in HKL48 and HKL99 were identified around RM7208 and RM6909, respectively on chromosome 4. Results from this study suggest the possibilities to use marker-assisted selection and pyramiding these QTLs to improve rice water productivity.

  16. Rapid, high-resolution measurement of leaf area and leaf orientation using terrestrial LiDAR scanning data

    Science.gov (United States)

    Bailey, Brian N.; Mahaffee, Walter F.

    2017-06-01

    The rapid evolution of high performance computing technology has allowed for the development of extremely detailed models of the urban and natural environment. Although models can now represent sub-meter-scale variability in environmental geometry, model users are often unable to specify the geometry of real domains at this scale given available measurements. An emerging technology in this field has been the use of terrestrial LiDAR scanning data to rapidly measure the three-dimensional geometry of trees, such as the distribution of leaf area. However, current LiDAR methods suffer from the limitation that they require detailed knowledge of leaf orientation in order to translate projected leaf area into actual leaf area. Common methods for measuring leaf orientation are often tedious or inaccurate, which places constraints on the LiDAR measurement technique. This work presents a new method to simultaneously measure leaf orientation and leaf area within an arbitrarily defined volume using terrestrial LiDAR data. The novelty of the method lies in the direct measurement of the fraction of projected leaf area G from the LiDAR data which is required to relate projected leaf area to total leaf area, and in the new way in which radiation transfer theory is used to calculate leaf area from the LiDAR data. The method was validated by comparing LiDAR-measured leaf area to (1) ‘synthetic’ or computer-generated LiDAR data where the exact area was known, and (2) direct measurements of leaf area in the field using destructive sampling. Overall, agreement between the LiDAR and reference measurements was very good, showing a normalized root-mean-squared-error of about 15% for the synthetic tests, and 13% in the field.

  17. Transcriptomic analysis of incised leaf-shape determination in birch.

    Science.gov (United States)

    Mu, Huaizhi; Lin, Lin; Liu, Guifeng; Jiang, Jing

    2013-12-01

    Plant researchers have focused much attention on leaf shape because of its importance in the identification. To evaluate the impact of intraspecies leaf-shape variation on the transcriptome, a series of Betula pendula 'Dalecarlica' and B. pendula saplings were generated through tissue culture. The leaf shapes and transcriptomes of B. pendula 'Dalecarlica' clones were compared with those of B. pendula clones. The leaf shape of B. pendula 'Dalecarlica' was incised and that of B. pendula was ovate. Transcriptome data revealed numerous changes in gene expression between B. pendula 'Dalecarlica' and B. pendula, including upregulation of 8767 unigenes and downregulation of 8379 unigenes in B. pendula 'Dalecarlica'. A pathway analysis revealed that the transport and signal transduction of auxin were altered in 'Dalecarlica', which may have contributed to its altered leaf shape. These results shed light on variation in birch leaf shape and help identify important genes for the genetic engineering of birch trees. © 2013.

  18. Latent developmental and evolutionary shapes embedded within the grapevine leaf

    OpenAIRE

    Chitwood, Daniel H.; Klein, Laura L.; O'Hanlon, Regan; Chacko, Steven; Greg, Matthew; Kitchen, Cassandra; Miller, Allison J.; Londo, Jason P.

    2015-01-01

    Summary Across plants, leaves exhibit profound diversity in shape. As a single leaf expands, its shape is in constant flux. Plants may also produce leaves with different shapes at successive nodes. In addition, leaf shape varies among individuals, populations and species as a result of evolutionary processes and environmental influences. Because leaf shape can vary in many different ways, theoretically, the effects of distinct developmental and evolutionary processes are separable, even withi...

  19. Generality of leaf trait relationships: A test across six biomes

    Energy Technology Data Exchange (ETDEWEB)

    Reich, P.B. [Univ. of Minnesota, Saint Paul, MN (United States). Dept. of Forest Resources; Ellsworth, D.S. [Brookhaven National Lab., Upton, NY (United States). Dept. of Applied Science; Walters, M.B. [Michigan State Univ., East Lansing, MI (United States). Dept. of Forestry; Vose, J.M. [Forest Service, Otto, NC (United States). Coweeta Hydrological Lab.; Gresham, C. [Clemson Univ., Georgetown, SC (United States). Baruch Forest Inst.; Volin, J.C. [Florida Atlantic Univ., Davie, FL (United States). Div. of Science; Bowman, W.D. [Inst. of Arctic and Alpine Research, Boulder, CO (United States). Mountain Research Station]|[Univ. of Colorado, Boulder, CO (United States). Dept. of Evolutionary, Population, and Organismic Biology

    1999-09-01

    Convergence in interspecific leaf trait relationships across diverse taxonomic groups and biomes would have important evolutionary and ecological implications. Such convergence has been hypothesized to result from trade-offs that limit the combination of plant traits for any species. Here the authors address this issue by testing for biome differences in the slope and intercept of interspecific relationships among leaf traits: longevity, net photosynthetic capacity (A{sub max}), leaf diffusive conductance (G{sub S}), specific leaf area (SLA), and nitrogen (N) status, for more than 100 species in six distinct biomes of the Americas. The six biomes were: alpine tundra-subalpine forest ecotone, cold temperate forest-prairie ecotone, montane cool temperate forest, desert shrubland, subtropical forest, and tropical rain forest. Despite large differences in climate and evolutionary history, in all biomes mass-based leaf N (N{sub mass}), SLA, G{sub S}, and A{sub max} were positively related to one another and decreased with increasing leaf life span. The relationships between pairs of leaf traits exhibited similar slopes among biomes, suggesting a predictable set of scaling relationships among key leaf morphological, chemical, and metabolic traits that are replicated globally among terrestrial ecosystems regardless of biome or vegetation type. However, the intercept (i.e., the overall elevation of regression lines) of relationships between pairs of leaf traits usually differed among biomes. With increasing aridity across sites, species had greater A{sub max} for a given level of G{sub S} and lower SLA for any given leaf life span. Using principal components analysis, most variation among species was explained by an axis related to mass-based leaf traits (A{sub max}, N, and SLA) while a second axis reflected climate, G{sub S}, and other area-based leaf traits.

  20. Wettability and water uptake of holm oak leaf surfaces

    OpenAIRE

    2014-01-01

    Plant trichomes play important protective functions and may have a major influence on leaf surface wettability. With the aim of gaining insight into trichome structure, composition and function in relation to water-plant surface interactions, we analyzed the adaxial and abaxial leaf surface of Quercus ilex L. (holm oak) as model. By measuring the leaf water potential 24 h after the deposition of water drops on to abaxial and adaxial surfaces, evidence for water penetration through the upper l...

  1. Properties of ligno-cellulose ficus religiosa leaf fibers

    CSIR Research Space (South Africa)

    Reddy, KO

    2010-04-01

    Full Text Available Religiosa Leaf Fibers International Journal of Polymers and Technologies • 2(1) January-April 2010 29 I J P T © Serials Publications * Corresponding author: E-mail: arajulu@rediffmail.com Properties of Ligno-cellulose Ficus Religiosa Leaf Fibers K. Obi... was also studied and the results are reported in this paper. MATERIALS AND METHODS Materials Extracted ficus leaf fibers, sodium hydroxide pellets (Merk, India), benzene, sodium chlorite, acetic acid, sodium bisulphate and ethanol (S...

  2. Study on Visualization Simulation of Soybean Leaf Based on IFS

    Institute of Scientific and Technical Information of China (English)

    XING Lichao; SU Zhongbin; ZHENG Pin; JING Liqun

    2008-01-01

    This article applied the self-similarity of fractal theory to the soybean leaf with the aid of powerful iterative computation ability of computer, analyzed the generation principle of IFS code in the iterated function system, calculated the IFS code of the simulation soybean leaf. It basically realized the visualization simulation of soybean leaf and laid a foundation for the visualization simulation of the whole soybean plant.

  3. GOLD IS EARNED FROM THE PRODUCTION OF THAI GOLD LEAF

    Directory of Open Access Journals (Sweden)

    Dirk Bax

    2010-06-01

    Full Text Available Thai people like to cover sacred objects or things dear to them with gold leaf.. Statues of Buddha are sometimes covered with so many layers of gold leaf that they become formless figures, that can hardly be recognized. Portraits of beloved ancestors, statues of elephants and grave tombs are often covered with gold leaf. If one considers the number of Thai people and the popularity of the habit, the amount of gold involved could be considerable.

  4. Simulation of Canopy Leaf Inclination Angle in Rice

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao-cui; LU Chuan-gen; HU Ning; YAO Ke-min; ZHANG Qi-jun; DAI Qi-gen

    2013-01-01

    A leaf inclination angle distribution model, which is applicable to simulate leaf inclination angle distribution in six heights of layered canopy at different growth stages, was established by component factors affecting plant type in rice. The accuracy of the simulation results was validated by measured values from a field experiment. The coefficient of determination (R2) and the root mean square error (RMSE) between the simulated and measured values were 0.9472 and 3.93%, respectively. The simulation results showed that the distribution of leaf inclination angles differed among the three plant types. The leaf inclination angles were larger in the compact variety Liangyoupeijiu with erect leaves than in the loose variety Shanyou 63 with droopy leaves and the intermediate variety Liangyou Y06. The leaf inclination angles were distributed in the lower range in Shanyou 63, which matched up with field measurements. The distribution of leaf inclination angles in the same variety changed throughout the seven growth stages. The leaf inclination angles enlarged gradually from transplanting to booting. During the post-booting period, the leaf inclination angle increased in Shanyou 63 and Liangyou Y06, but changed little in Liangyoupeijiu. At every growth stage of each variety, canopy leaf inclination angle distribution on the six heights of canopy layers was variable. As canopy height increased, the layered leaf area index (LAI) decreased in all the three plant types. However, while the leaf inclination angles showed little change in Liangyoupeijiu, they became larger in Shanyou 63 but smaller in Liangyou Y06. The simulation results used in the constructed model were very similar to the actual measurement values. The model provides a method for estimating canopy leaf inclination angle distribution in rice production.

  5. A Study of Sugarcane Leaf-Removal Machinery during Harvest

    OpenAIRE

    2010-01-01

    Problem statement: Sugarcane leaf-removing tools could help speed up sugarcane harvest and reduce contamination. Moreover, leaf-removal machinery can solve the problems of sugarcane burning and workers can increase sugarcane harvest production too. The purpose of this research was to study the use of leaf-removal machinery in the post-harvest production of sugarcane to reduce harvest production time and contaminant. Approach: This study focused on the LK92-11 variety of sugarcane having a har...

  6. EXPERIMENTAL INVESTIGATION & NUMERICAL ANALYSIS OF COMPOSITE LEAF SPRING

    OpenAIRE

    K. K. JADHAO,; DR. R.S DALU

    2011-01-01

    The Automobile Industry has shown keen interest for replacement of steel leaf spring with that of glass fiber composite leaf spring, since the composite material has high strength to weight ratio, good corrosion resistance and tailor-able properties. The objective of present study was to replace material for leaf spring. In present study the material selected was glass fiber reinforced plastic (GFRP) and the polyester resin (NETPOL 1011) can be used which was more economical this will reduce ...

  7. Regulation of leaf hydraulics: from molecular to whole plant levels

    OpenAIRE

    2013-01-01

    The water status of plant leaves is dependent on both stomatal regulation and water supply from the vasculature to inner tissues. The present review addresses the multiple physiological and mechanistic facets of the latter process. Inner leaf tissues contribute to at least a third of the whole resistance to water flow within the plant. Physiological studies indicated that leaf hydraulic conductance (Kleaf) is highly dependent on the anatomy, development and age of the leaf and can vary rapidl...

  8. Quantitative trait loci analysis of leaf morphology in rice

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@The leaf morphology traits are important componem part of rice ideotype. The present study was conducted with a doubled haploid(DH) population of 117 lines derived from a cross between an indica variety, Zhaiyeqing 8(ZYQ 8) and a japonica variety, Jingxi 17(JX 17). The QTLs responsible for area, perimeter, length, width, and length/width of flag leaf, the second upside-down leaf, and the third upside-down leaf were surveyed and analyzed based on genetic linkage map of 243 molecular markers.

  9. Silver nano fabrication using leaf disc of Passiflora foetida Linn

    Science.gov (United States)

    Lade, Bipin D.; Patil, Anita S.

    2017-06-01

    The main purpose of the experiment is to develop a greener low cost SNP fabrication steps using factories of secondary metabolites from Passiflora leaf extract. Here, the leaf extraction process is omitted, and instead a leaf disc was used for stable SNP fabricated by optimizing parameters such as a circular leaf disc of 2 cm (1, 2, 3, 4, 5) instead of leaf extract and grade of pH (7, 8, 9, 11). The SNP synthesis reaction is tried under room temperature, sun, UV and dark condition. The leaf disc preparation steps are also discussed in details. The SNP obtained using (1 mM: 100 ml AgNO3+ singular leaf disc: pH 9, 11) is applied against featured room temperature and sun condition. The UV spectroscopic analysis confirms that sun rays synthesized SNP yields stable nano particles. The FTIR analysis confirms a large number of functional groups such as alkanes, alkyne, amines, aliphatic amine, carboxylic acid; nitro-compound, alcohol, saturated aldehyde and phenols involved in reduction of silver salt to zero valent ions. The leaf disc mediated synthesis of silver nanoparticles, minimizes leaf extract preparation step and eligible for stable SNP synthesis. The methods sun and room temperature based nano particles synthesized within 10 min would be use certainly for antimicrobial activity.

  10. Optimizing the extraction of antibacterial compounds from pineapple leaf fiber

    National Research Council Canada - National Science Library

    Zhikai Zhuang; Jin Zhang; Mingfu Li; Ganran Deng; Zhongqing Ou; Wenwei Lian; Junyan He; Tao Huang

    2016-01-01

    ...) were used to extract antibacterial compounds from pineapple leaf fiber. Compounds extracted using acetone showed the greatest antibacterial effect against , measured by inhibition zone diameter...

  11. Antibacterial activity of various leaf extracts of Merremia emarginata

    Institute of Scientific and Technical Information of China (English)

    EK Elumalai; M Ramachandran; T Thirumalai; P Vinothkumar

    2011-01-01

    Objective: To investigate the antibacterial activity and phytochemical screening of the aqueous, methanol and petroleum ether leaf extracts of Merremia emarginata (M. emarginata). Methods:The antibacterial activity of leaf extracts of M. emarginata were evaluated by agar well diffusion method against four selected bacterial species. Results: The presence of tannins, flavonoids, amino acids, starch, glycosides and carbohydrates in the different leaf extracts was established. The methanol extract was more effective against Bacillus cereus and Escherichia coli, whereas aqueous extract was more effective against Staphylococcus aureus and Pseudomonas aeruginosa.Conclusions: The results in the present study suggest that M. emarginata leaf can be used in treating diseases caused by the tested organisms.

  12. Leaf size indices and structure of the peat swamp forest

    Directory of Open Access Journals (Sweden)

    L.G. Aribal

    2017-12-01

    Full Text Available Leaf size indices of the tree species in the peatland of Agusan del Sur in Mindanao in Philippines was examined to deduce the variation of forest structure and observed forest zonation.  Using raunkiaer and webb’s leaf size classification, the leaf morphometrics of seven tree species consistently found on the established sampling plots were determined.  The species includes Ternstroemia philippinensis Merr., Polyscias aherniana Merr. Lowry and G.M. Plunkett, Calophyllum sclerophyllum Vesque, Fagraea racemosa Jack, Ilex cymosa Blume, Syzygium tenuirame (Miq. Merr. and Tristaniopsis micrantha Merr. Peter G.Wilson and J.T.Waterh.The LSI were correlated against the variables of the peat physico-chemical properties (such as bulk density, acrotelm thickness, peat depth, total organic carbon, nitrogen, phosphorus, and potassium, pH; water (pH, ammonium, nitrate, phosphate; and leaf tissue elements (nitrogen, phosphorus and potassium.  Result showed a decreasing leaf size indices and a three leaf size category consisting of mesophyllous, mesophyllous-notophyllous and microphyllous were observed which corresponds to the structure of vegetation i.e., from the tall-pole forest having the biggest average leaf area of 6,142.29 mm2 to the pygmy forest with average leaf area of 1,670.10 mm2.  Such decreased leaf size indices were strongly correlated to soil nitrogen, acrotelm thickness, peat depth, phosphate in water, nitrogen and phosphorus in the plant tissue.

  13. Do general patterns of leaf thermoregulation hold in the tropics?

    Science.gov (United States)

    Michaletz, S. T.; Blonder, B.; Chambers, J.; Enquist, B. J.; Faybishenko, B.; Grossiord, C.; Jardine, K.; Negron Juarez, R. I.; Varadharajan, C.; McDowell, N. G.; Detto, M.; Wolfe, B.

    2016-12-01

    Leaf temperature is a critical driver of plant and ecosystem functioning because it governs rates of photosynthesis and transpiration. While leaf temperatures are often assumed to equal ambient air temperatures, recent studies show that leaves thermoregulate, so they are warmer than air in cool temperatures and cooler than air in warm temperatures. This pattern appears to be general across diverse plant taxa and boreal-to-subtropical air temperature gradients. However, one exception to the general pattern may be the tropics, where scant data suggest that daytime leaf temperatures are always warmer and increase at a faster rate than air temperature, possibly because transpiration and latent heat fluxes are limited by high relative humidity. In this talk, we evaluate tropical leaf thermoregulation using new data from the DOE Next Generation Ecosystem Experiments-Tropics project and a recent analytical energy budget model for leaf temperature. The model expresses leaf temperature as a linear function of air temperature, several additional meteorological variables, and several leaf functional traits. We examine patterns of tropical leaf thermoregulation and identify the relative importance of meteorological variables and leaf traits in driving these patterns. Our results demonstrate that the temperatures of plant tissues, and not just air, are vital to developing more accurate earth system models.

  14. LEAF AREA ESTIMATION IN LITCHI BY MEANS OF ALLOMETRIC RELATIONSHIPS

    Directory of Open Access Journals (Sweden)

    PABLO SOUTO OLIVEIRA

    Full Text Available ABSTRACT Obtaining leaf area is critical in several agronomic studies, being one of the important instruments to assess plant growth. The aim of this study was to estimate equations and select the most appropriate in determining leaf area in litchi (Litchi chinensis Sonn.. From the linear dimensions of length (L and maximum width (W of leaf limb, equations were estimated using linear, quadratic, potential and exponential models. The linear regression equation using the product of the length by maximum width, given by Y = 0.2885 + 0.662 (L.W is the one that best expresses the leaf area estimation of litchi tree.

  15. Side Effects of Fungicides Used in Cucurbitaceous Crop on Trichogrammaatopovirilia Oatman & Platner (Hymenoptera: Trichogramatidae Efectos Secundarios sobre Trichogramma atopovirilia Oatman & Platner (Hymenoptera: Trichogramatidae de Fungicidas usados en Cucurbitáceas

    Directory of Open Access Journals (Sweden)

    Dirceu Pratissoli

    2010-06-01

    producción de cucurbitáceas en Trichogramma atopovirilia Oatman & Platner sobre huevos de D. hyalinata. Se evaluaron los fungicidas azoxystrobina (0.08 g ingrediente activo [ia] L-1, clorotalonil (2.00 g ia L-1, mancozeb (1.60 g ia L-1, tebuconazole (0.25 g ia L-1 and tiofanato-metil (0.49 g ia L-1. Tarjetas con 30 huevos de D. hyalinata previamente sumergidos en los fungicidas y en agua destilada (control fueron ofrecidas a 20 hembras de T. atopovirilia con hasta 24 h de emergencia individualizadas en tubos de vidrio. Se evaluó parasitismo, reducción de parasitismo, emergencia, proporción sexual en la población y el número de individuos emergidos por huevo. Los fungicidas clorotalonil, tiofanato-metil y tebuconazol redujeron el parasitismo de T. atopovirilia en 43,37; 27,64 y 18,51%, respectivamente. Sin embargo, el parasitismo con azoxistrobina (79,21% fue mayor que el control (67,37% (P ≤ 0,05. Clorotalonil, tiofanato-metilo y el tebuconazol redujo la aparición de 73,77, 75,62 y 79,35% (P ≤ 0,05, respectivamente. Azoxistrobina y tiofanato-metil reduciran la proporción de sexos de 0,77 y 0,76 (P ≤ 0,05, respectivamente. Ninguno de los fungicidas redujo el número de individuos por cada huevo. Los fungicidas azoxistrobina y mancozeb fueron selectivos para T. atopovirilia en la mayoría de los parámetros estudiados, por lo tanto, deberían tener prioridad en el manejo de enfermedades de cucurbitáceas para permitir el uso eficiente de los enemigos naturales de D. hyalinata.

  16. Accumulation of three different sizes of particulate matter on plant leaf surfaces: Effect on leaf traits

    Directory of Open Access Journals (Sweden)

    Chen Xiaoping

    2015-01-01

    Full Text Available Plants not only improve air quality by adsorbing particulate matter (PM on leaf surfaces but can also be affected by their accumulation. In this study, a field investigation was performed in Wuhan, China, into the relationship between seven leaf traits and the accumulation of three different sizes of PM (PM11, PM2.5 and PM0.2 on leaves. The retention abilities of plant leaves with respect to the three sizes of PM differed significantly at different sites and species. The average PM retention capabilities of plant leaves and specific leaf area (SLA were significantly greater in a seriously polluted area, whereas the average values of chlorophyll a (Chl a, chlorophyll b (Chl b, total chlorophyll, carotenoid, pH and relative water content (RWC were greater at the control site. SLA significantly positively correlated with the size of PM, but Chl a, Chl b, total chlorophyll, RWC significantly negatively correlated with the size of PM, whereas the pH did not correlate significantly with the the PM fractions. Additionally, SLA was found to be affected by large particles (PM11, p<0.01; PM2.5 had a more obvious effect on plant leaf traits than the other PM (p<0.05. Overall, the findings from this study provide useful information regarding the selection of plants to reduce atmospheric pollution.

  17. Leaf nutrient resorption, leaf lifespan and the retention of nutrients in seagrass systems

    NARCIS (Netherlands)

    Hemminga, M.A.; Marbà, N.; Stapel, J.

    1999-01-01

    Efficient nutrient resorption from senescing leaves, and extended leaf life spans are important strategies in order to conserve nutrients for plants in general. Despite the fact that seagrasses often grow in oligotrophic waters, these conservation strategies are not strongly developed in seagrasses.

  18. NARROW AND ROLLED LEAF 2 regulates leaf shape, male fertility, and seed size in rice

    Institute of Scientific and Technical Information of China (English)

    Shuangshuang Zhao; Lei Zhao; Fengxia Liu; Yongzhen Wu; Zuofeng Zhu; Chuanqing Sun; Lubin Tan

    2016-01-01

    Grain yield in rice (Oryza sativa L.) is closely related to leaf and flower development. Coordinative regulation of leaf, pollen, and seed development in rice as a critical biological and agricultural question should be addressed. Here we identified two allelic rice mutants with narrow and semi-rolled leaves, named narrow and rolled leaf 2-1 (nrl2-1) and nrl2-2. Map-based molecular cloning revealed that NRL2 encodes a novel protein with unknown biochemical function. The mutation of NRL2 caused pleiotropic effects, including a reduction in the number of longitudinal veins, defective abaxial sclerenchymatous cell differentiation, abnormal tape-tum degeneration and microspore development, and the formation of more slender seeds compared with the wild type (WT). The NRL2 protein interacted with Rolling-leaf (RL14), causing the leaves of the nrl2 mutants to have a higher cellulose content and lower lignin content than the WT, which may have been related to sclerenchymatous cell differentia-tion and tapetum degeneration. Thus, this gene is an essential developmental regulator controlling fundamental cellular and developmental processes, serving as a potential breeding target for high-yielding rice cultivars.

  19. On the temporal variation of leaf magnetic parameters: seasonal accumulation of leaf-deposited and leaf-encapsulated particles of a roadside tree crown.

    Science.gov (United States)

    Hofman, Jelle; Wuyts, Karen; Van Wittenberghe, Shari; Samson, Roeland

    2014-09-15

    Understanding the accumulation behaviour of atmospheric particles inside tree leaves is of great importance for the interpretation of biomagnetic monitoring results. In this study, we evaluated the temporal variation of the saturation isothermal remanent magnetisation (SIRM) of leaves of a roadside urban Platanus × acerifolia Willd. tree in Antwerp, Belgium. We hereby examined the seasonal development of the total leaf SIRM signal as well as the leaf-encapsulated fraction of the deposited dust, by washing the leaves before biomagnetic analysis. On average 38% of the leaf SIRM signal was exhibited by the leaf-encapsulated particles. Significant correlations were found between the SIRM and the cumulative daily average atmospheric PM10 and PM2.5 measurements. Moreover, a steady increase of the SIRM throughout the in-leaf season was observed endorsing the applicability of biomagnetic monitoring as a proxy for the time-integrated PM exposure of urban tree leaves. Strongest correlations were obtained for the SIRM of the leaf-encapsulated particles which confirms the dynamic nature of the leaf surface-accumulated particles.

  20. Leaf thickness controls variation in leaf mass per area (LMA) among grazing-adapted grasses in Serengeti.

    Science.gov (United States)

    Griffith, Daniel M; Quigley, Kathleen M; Anderson, T Michael

    2016-08-01

    Leaf mass per area (LMA) is a primary plant functional trait that represents the cost of constructing a leaf. Ultimately, plants modify LMA by altering leaf thickness (LT), leaf dry matter content (LDMC), or both. While LMA can be modified through both of these constituents, studies of LMA have found that there is variation in whether LT or LDMC changes are responsible for LMA-and the relationships change depending on the species or functional groups being compared. In this study, we used a phylogenetic framework to determine that evolutionary shifts in LMA are driven by LT, and not LDMC, among 45 Serengeti grass species. We considered two alternative hypotheses that could result in evolutionary correlation of LMA on LT but not LDMC: either (1) LT is more labile than LDMC-and is therefore a less costly means to change LMA or (2) LDMC is tightly coupled to a different dimension of leaf variation (e.g., leaf hydraulics), leaving LT as the source of variation in LMA. LT was not more labile than LDMC, leading us to conclude that the evolution of LMA has been shaped by LT because LDMC is responding to other demands on leaf physiology. We speculate that leaf hydraulics provide this constraint on LDMC. The decoupling of LDMC from LT may allow plants to better optimize resource allocation in ecosystems where gradients in light competition, herbivory, and aridity place competing demands on leaf economics.

  1. Leaf Breakdown in a Tropical Stream

    Science.gov (United States)

    Gonçalves, José Francisco, Jr.; França, Juliana S.; Medeiros, Adriana O.; Rosa, Carlos A.; Callisto, Marcos

    2006-05-01

    The objectives of this study were to investigate leaf breakdown in two reaches of different magnitudes, one of a 3rd (closed riparian vegetation) order and the other of a 4th (open riparian vegetation) order, in a tropical stream and to assess the colonization of invertebrates and microorganisms during the processing of detritus. We observed that the detritus in a reach of 4th order decomposed 2.4 times faster than the detritus in a reach of 3rd order, in which, we observed that nitrate concentration and water velocity were greater. This study showed that the chemical composition of detritus does not appear to be important in evaluating leaf breakdown. However, it was shown to be important to biological colonization. The invertebrate community appeared not to have been structured by the decomposition process, but instead by the degradative ecological succession process. With regards to biological colonization, we observed that the density of bacteria in the initial stages was more important while fungi appeared more in the intermediate and final stages.

  2. Intraspecific growth and functional leaf trait responses to natural soil resource gradients for conifer species with contrasting leaf habit.

    Science.gov (United States)

    Walters, Michael B; Gerlach, John P

    2013-03-01

    Interspecific relationships among species mean leaf traits, performance and species resource/climate distributions help provide the foundation for a predictive, functionally based plant ecology. Intraspecific responses of leaf traits and performance to resource gradients and how these vary among species may be equally important but have received less attention. Here, we examine relationships between proxies of soil resource availability, leaf traits and growth (height at 25 years, SI25) for winter deciduous Larix decidua Mill. and evergreen Pinus resinosa Ait. trees distributed over soil resource gradients in the Great Lakes region of North America. We predicted that (i) leaf trait responses to soil resources within species will be similar to reported distributions of mean leaf traits over soil resource gradients among species; (ii) soil resource-related variation in leaf traits can help explain SI25; and (iii) SI25 will be greater for Larix than Pinus at higher soil resources and greater for Pinus than Larix at lower soil resources and this pattern will be associated with species differences in leaf trait responses to soil resources. Among the measured leaf traits (live N, Mg, Ca, K, P, and Mn, litter N, N resorption, carbon isotope discrimination, specific leaf area, lifespan), soil resources only impacted live and litter N for both species and K for Pinus. In turn, only the leaf traits responsive to soil resources affected SI25 in the expected manner. Larix had greater SI25 than Pinus across soil resource gradients and both species had similar growth and leaf trait sensitivities to resources. In summary: (i) several leaf traits reported to be associated with performance and edaphic distributions across species were, within species, unresponsive to nitrogen and water availability and unrelated to growth; (ii) leaf N showed high plasticity to soil resources and this plasticity was functionally relevant to growth over its entire range of response; (iii) large

  3. The dosimetric impact of leaf interdigitation and leaf width on VMAT treatment planning in Pinnacle: comparing Pareto fronts.

    Science.gov (United States)

    van Kesteren, Z; Janssen, T M; Damen, E; van Vliet-Vroegindeweij, C

    2012-05-21

    To evaluate in an objective way the effect of leaf interdigitation and leaf width on volumetric modulated arc therapy plans in Pinnacle. Three multileaf collimators (MLCs) were modeled: two 10 mm leaf width MLCs, with and without interdigitating leafs, and a 5 mm leaf width MLC with interdigitating leafs. Three rectum patients and three prostate patients were used for the planning study. In order to compare treatment techniques in an objective way, a Pareto front comparison was carried out. 200 plans were generated in an automated way, per patient per MLC model, resulting in a total of 3600 plans. From these plans, Pareto-optimal plans were selected which were evaluated for various dosimetric variables. The capability of leaf interdigitation showed little dosimetric impact on the treatment plans, when comparing the 10 mm leaf width MLC with and without leaf interdigitation. When comparing the 10 mm leaf width MLC with the 5 mm leaf width MLC, both with interdigitating leafs, improvement in plan quality was observed. For both patient groups, the integral dose was reduced by 0.6 J for the thin MLC. For the prostate patients, the mean dose to the anal sphincter was reduced by 1.8 Gy and the conformity of the V(95%) was reduced by 0.02 using the thin MLC. The V(65%) of the rectum was reduced by 0.1% and the dose homogeneity with 1.5%. For rectum patients, the mean dose to the bowel was reduced by 1.4 Gy and the mean dose to the bladder with 0.8 Gy for the thin MLC. The conformity of the V(95%) was equivalent for the 10 and 5 mm leaf width MLCs for the rectum patients. We have objectively compared three types of MLCs in a planning study for prostate and rectum patients by analyzing Pareto-optimal plans which were generated in an automated way. Interdigitation of MLC leafs does not generate better plans using the SmartArc algorithm in Pinnacle. Changing the MLC leaf width from 10 to 5 mm generates better treatment plans although the clinical relevance remains

  4. Wind induced deformation and vibration of a Platanus acerifolia leaf

    Institute of Scientific and Technical Information of China (English)

    Chuan-Ping Shao; Ye-Jun Chen; Jian-Zhong Lin

    2012-01-01

    Deformation and vibration of twig-connected single leaf in wind is investigated experimentally.Results show that the Reynolds number based on wind speed and length of leaf blade is a key parameter to the aerodynamic problem.In case the front surface facing the wind and with an increase of Reynolds number,the leaf experiences static deformation,large amplitude and low frequency sway,reconfiguration to delta wing shape,flapping of tips,high frequency vibration of whole leaf blade,recovery of delta wing shape,and twig-leaf coupling vibration.Abrupt changes from one state to another occur at critical Reynolds numbers.In case the back surfacc facing the wind,the large amplitude and low frequency sway does not occur,the recovered delta wing shape is replaced by a conic shape,and the critical Reynolds numbers of vibrations are higher than the ones corresponding to the case with the front surface facing the wind.A pair of ram-horn vortex is observed behind the delta wing shaped leaf.A single vortex is found downstream of the conic shaped leaf.A lift is induced by the vortex,and this lift helps leaf to adjust position and posture,stabilize blade distortion and reduce drag and vibration.

  5. Effects of leaf area of downy oak (Quercus pubescens Willd ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-08-18

    Aug 18, 2009 ... gravity meter with sensitivity of 0.01 g and by means of formula 1. The 1st and 2nd age ... multiplying these values the area of a leaf (l.a, mm2) is calculated. 4. ..... Considering obtained data from this study of effects of leaf area ...

  6. Incomplete resistance to coffee leaf rust (Hemileia vastatrix)

    NARCIS (Netherlands)

    Eskes, T.K.A.B.

    1983-01-01

    Incomplete resistance to coffee leaf rust ( Hemileia vastatrix ) may be of value in obtaining durable resistance, which is of great importance for the perennial coffee crop. Methods were developed to assess incomplete resistance to coffee leaf rust by using illustrated scales ranging from 0 t

  7. Incomplete resistance to coffee leaf rust (Hemileia vastatrix)

    NARCIS (Netherlands)

    Eskes, A.B.

    1983-01-01

    Incomplete resistance to coffee leaf rust ( Hemileia vastatrix ) may be of value in obtaining durable resistance, which is of great importance for the perennial coffee crop. Methods were developed to assess incomplete resistance to coffee leaf rust by using illustrated scales

  8. The emission of volatile compounds from leaf litter

    NARCIS (Netherlands)

    Derendorp, L.

    2012-01-01

    Leaf litter is available at the Earth’s surface in large quantities. During the decomposition of leaf litter, volatile compounds can be released into the atmosphere, where they potentially influence local air quality, atmospheric chemistry or the global climate. In this thesis the focus was on the e

  9. Leaf senescence in alstroemeria: regulation by phytochrome gibberellins and cytokinins.

    NARCIS (Netherlands)

    Kappers, I.

    1998-01-01

    Leaf senescence in plants is a regulated process influenced by light as well as phytohormones. In the present study the putative role of the phytohormones cytokinins and gibberellins as mediators for the light signal on leaf senescence in alstroemeria was studied. It was found that low photon fluenc

  10. 7 CFR 29.3153 - Leaf (B Group).

    Science.gov (United States)

    2010-01-01

    ... Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing...″ or over in length, 70 percent uniform, and 30 percent injury tolerance. B2M Fine Mixed Color Leaf... percent uniform, and 10 percent injury tolerance. B3M Good Mixed Color Leaf. Fleshy to medium body,...

  11. Coconut leaf bioactivity toward generalist maize insect pests

    Science.gov (United States)

    Tropical plants are often more resistant to insects than temperate plants due to evolution of robust defenses to cope with a more constant insect threat. Coconut (Cocos nucifera L.) has very few chewing leaf feeding insect pests and was tested against two omnivorous leaf feeding caterpillar species,...

  12. Ozone exposure affects leaf wettability and tree water balance

    NARCIS (Netherlands)

    Schreuder, M.D.J.; Hove, van L.W.A.; Brewer, C.A.

    2001-01-01

    Relatively little is known about the influences of growing-season background ozone (O3) concentrations on leaf cuticles and foliar water loss. Using fumigation chambers, leaf wettability and foliar water loss were studied in two poplar species, Populus nigra and P. euramericana, and a conifer, Pseud

  13. Biophysical constraints on leaf expansion in a tall conifer.

    Science.gov (United States)

    Fredrick C. Meinzer; Barbara J. Bond; Jennifer A. Karanian

    2008-01-01

    The physiological mechanisms responsible for reduced extension growth as trees increase in height remain elusive. We evaluated biophysical constraints on leaf expansion in old-growth Douglas-fir (Psuedotsuga menziesii (Mirb.) Franco) trees. Needle elongation rates, plastic and elastic extensibility, bulk leaf water, (L...

  14. Morphology and inheritance of a new rice leaf death mutant

    Institute of Scientific and Technical Information of China (English)

    CHENGZhakuan; GUMingkang

    1998-01-01

    A new mutant showing successive leaf death was selected in a mutmion populalion from an indica rice variety Zhongxian 3037 trealed with 94Co-γ rays. The leaves of this rnutanl began lodie on the emergence of tlle third leaf tip, and all leaves died sooner alter flowering. Consequently,

  15. Ontogeny of the sheathing leaf base in maize (Zea mays).

    Science.gov (United States)

    Johnston, Robyn; Leiboff, Samuel; Scanlon, Michael J

    2015-01-01

    Leaves develop from the shoot apical meristem (SAM) via recruitment of leaf founder cells. Unlike eudicots, most monocot leaves display parallel venation and sheathing bases wherein the margins overlap the stem. Here we utilized computed tomography (CT) imaging, localization of PIN-FORMED1 (PIN1) auxin transport proteins, and in situ hybridization of leaf developmental transcripts to analyze the ontogeny of monocot leaf morphology in maize (Zea mays). CT imaging of whole-mounted shoot apices illustrates the plastochron-specific stages during initiation of the basal sheath margins from the tubular disc of insertion (DOI). PIN1 localizations identify basipetal auxin transport in the SAM L1 layer at the site of leaf initiation, a process that continues reiteratively during later recruitment of lateral leaf domains. Refinement of these auxin transport domains results in multiple, parallel provascular strands within the initiating primordium. By contrast, auxin is transported from the L2 toward the L1 at the developing margins of the leaf sheath. Transcripts involved in organ boundary formation and dorsiventral patterning accumulate within the DOI, preceding the outgrowth of the overlapping margins of the sheathing leaf base. We suggest a model wherein sheathing bases and parallel veins are both patterned via the extended recruitment of lateral maize leaf domains from the SAM.

  16. Evolutionarily Stable Leaf Area Production in Plant Populations

    NARCIS (Netherlands)

    Anten, N.P.R.

    2002-01-01

    Using an analytical model, it was shown that for a given amount of nitrogen in the canopy of a stand (N-T), there exists an evolutionarily stable leaf area index (ES-LAI), and therefore an evolutionarily stable average leaf nitrogen content (n(anu)(ES); n(anu)(ES) = N-T/ES - LAI), at which no indivi

  17. The emission of volatile compounds from leaf litter

    NARCIS (Netherlands)

    Derendorp, L.|info:eu-repo/dai/nl/314016414

    2012-01-01

    Leaf litter is available at the Earth’s surface in large quantities. During the decomposition of leaf litter, volatile compounds can be released into the atmosphere, where they potentially influence local air quality, atmospheric chemistry or the global climate. In this thesis the focus was on the

  18. 7 CFR 51.1220 - Leaf or limb rub injury.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf or limb rub injury. 51.1220 Section 51.1220... MARKETING ACT OF 1946 FRESH FRUITS, VEGETABLES AND OTHER PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Grades of Peaches Definitions § 51.1220 Leaf or limb rub injury...

  19. Effects of nitrogen application rate and leaf age on the distribution pattern of leaf SPAD readings in the rice canopy.

    Directory of Open Access Journals (Sweden)

    Hu Yang

    Full Text Available A Soil-Plant Analysis Development (SPAD chlorophyll meter can be used as a simple tool for evaluating N concentration of the leaf and investigating the combined effects of nitrogen rate and leaf age on N distribution. We conducted experiments in a paddy field over two consecutive years (2008-2009 using rice plants treated with six different N application levels. N distribution pattern was determined by SPAD readings based on the temporal dynamics of N concentrations in individual leaves. At 62 days after transplantation (DAT in 2008 and DAT 60 in 2009, leaf SPAD readings increased from the upper to lower in the rice canopy that received N levels of 150 to 375 kg ha(-1The differences in SPAD readings between the upper and lower leaf were larger under higher N application rates. However, as plants grew, this atypical distribution of SPAD readings in canopy leaf quickly reversed to the general order. In addition, temporal dynamics of the leaf SPAD readings (N concentrations were fitted to a piecewise function. In our model, changes in leaf SPAD readings were divided into three stages: growth, functioning, and senescence periods. The leaf growth period lasted approximately 6 days, and cumulative growing days were not affected by N application rates. The leaf functioning period was represented with a relatively stable SPAD reading related to N application rate, and cumulative growing days were extended with increasing N application rates. A quadratic equation was utilized to describe the relationship between SPAD readings and leaf age during the leaf senescence period. The rate of decrease in SPAD readings increased with the age of leaves, but the rate was slowed by N application. As leaves in the lower canopy were physiologically older than leaves in the upper canopy, the rate of decrease in SPAD readings was faster in the lower leaves.

  20. Pulvinus activity, leaf movement and leaf water-use efficiency of bush bean ( Phaseplus vulgaris L.) in a hot environment

    Science.gov (United States)

    Raeini-Sarjaz, Mahmoud; Chalavi, Vida

    2008-11-01

    Pulvinus activity of Phaseolus species in response to environmental stimuli plays an essential role in heliotropic leaf movement. The aims of this study were to monitor the continuous daily pulvinus movement and pulvinus temperature, and to evaluate the effects of leaf movements, on a hot day, on instantaneous leaf water-use efficiency (WUEi), leaf gas exchange, and leaf temperature. Potted plants of Phaseolus vulgaris L. var. Provider were grown in Chicot sandy loam soil under well-watered conditions in a greenhouse. When the second trifoliate leaf was completely extended, one plant was selected to measure pulvinus movement using a beta-ray gauging (BRG) meter with a point source of thallium-204 (204Tl). Leaf gas exchange measurements took place on similar leaflets of three plants at an air temperature interval of 33-42°C by a steady-state LI-6200 photosynthesis system. A copper-constantan thermocouple was used to monitor pulvinus temperature. Pulvinus bending followed the daily diurnal rhythm. Significant correlations were found between the leaf-incident angle and the stomatal conductance ( R 2 = 0.54; P < 0.01), and photosynthesis rate ( R 2 = 0.84; P < 0.01). With a reduction in leaf-incidence angle and increase in air temperature, WUEi was reduced. During the measurements, leaf temperature remained below air temperature and was a significant function of air temperature ( r = 0.92; P < 0.01). In conclusion, pulvinus bending followed both light intensity and air temperature and influenced leaf gas exchange.

  1. A non-destructive method for estimating onion leaf area

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    Córcoles J.I.

    2015-06-01

    Full Text Available Leaf area is one of the most important parameters for characterizing crop growth and development, and its measurement is useful for examining the effects of agronomic management on crop production. It is related to interception of radiation, photosynthesis, biomass accumulation, transpiration and gas exchange in crop canopies. Several direct and indirect methods have been developed for determining leaf area. The aim of this study is to develop an indirect method, based on the use of a mathematical model, to compute leaf area in an onion crop using non-destructive measurements with the condition that the model must be practical and useful as a Decision Support System tool to improve crop management. A field experiment was conducted in a 4.75 ha commercial onion plot irrigated with a centre pivot system in Aguas Nuevas (Albacete, Spain, during the 2010 irrigation season. To determine onion crop leaf area in the laboratory, the crop was sampled on four occasions between 15 June and 15 September. At each sampling event, eight experimental plots of 1 m2 were used and the leaf area for individual leaves was computed using two indirect methods, one based on the use of an automated infrared imaging system, LI-COR-3100C, and the other using a digital scanner EPSON GT-8000, obtaining several images that were processed using Image J v 1.43 software. A total of 1146 leaves were used. Before measuring the leaf area, 25 parameters related to leaf length and width were determined for each leaf. The combined application of principal components analysis and cluster analysis for grouping leaf parameters was used to reduce the number of variables from 25 to 12. The parameter derived from the product of the total leaf length (L and the leaf diameter at a distance of 25% of the total leaf length (A25 gave the best results for estimating leaf area using a simple linear regression model. The model obtained was useful for computing leaf area using a non

  2. Chloroplast division during leaf development of Xanthium pensylvanicum Wallr. (Compositae

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    Roman Maksymowych

    2014-02-01

    Full Text Available Division and growth of chloroplasts was studied during leaf development of Xanthium pensylvanicum at various stages of development represented by the leaf plastochron index.Between leaf plastochron indices -1.00 and 2.56 chloroplast division was observed with little enlargement. Between 2.50 and 5.00 chloroplasts enlarged in diameter with an average rate of 0.21 µm per day. At leaf plastochron index 5.00 chloroplasts attained their mature size of 6.12 µm. No chloroplast division was found after leaf plastochron index 2.50. A change in shape of plastids from spherical proplastids to discoidal accompanied their growth during stages 2.50 and 5.00.

  3. Identification and Classification of Leaf Diseases in Turmeric Plants

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    Nandhini M,

    2016-02-01

    Full Text Available Plant disease identification is the most important sector in agriculture. Turmeric is one of the important rhizomatous crops grown in India. The turmeric leaf is highly exposed to diseases like rhizome rot, leaf spot, and leaf blotch. The identification of plant diseases requires close monitoring and hence this paper adopts technologies to manage turmeric plant diseases caused by fungi to enable production of high quality crop yields. Various image processing and machine learning techniques are used to identify and classify the diseases in turmeric leaf. The dataset with 800 leaf images of different categories were pre-processed and segmented to promote efficient feature extraction. Machine learning algorithms like support vector machine, decision tree and naïve bayes were applied to train the model. The performance of the model was evaluated using 10 fold cross validation and the results are reported.

  4. Functional overlap of the Arabidopsis leaf and root microbiota.

    Science.gov (United States)

    Bai, Yang; Müller, Daniel B; Srinivas, Girish; Garrido-Oter, Ruben; Potthoff, Eva; Rott, Matthias; Dombrowski, Nina; Münch, Philipp C; Spaepen, Stijn; Remus-Emsermann, Mitja; Hüttel, Bruno; McHardy, Alice C; Vorholt, Julia A; Schulze-Lefert, Paul

    2015-12-17

    Roots and leaves of healthy plants host taxonomically structured bacterial assemblies, and members of these communities contribute to plant growth and health. We established Arabidopsis leaf- and root-derived microbiota culture collections representing the majority of bacterial species that are reproducibly detectable by culture-independent community sequencing. We found an extensive taxonomic overlap between the leaf and root microbiota. Genome drafts of 400 isolates revealed a large overlap of genome-encoded functional capabilities between leaf- and root-derived bacteria with few significant differences at the level of individual functional categories. Using defined bacterial communities and a gnotobiotic Arabidopsis plant system we show that the isolates form assemblies resembling natural microbiota on their cognate host organs, but are also capable of ectopic leaf or root colonization. While this raises the possibility of reciprocal relocation between root and leaf microbiota members, genome information and recolonization experiments also provide evidence for microbiota specialization to their respective niche.

  5. Understanding of Leaf Development—the Science of Complexity

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    Robert Malinowski

    2013-06-01

    Full Text Available The leaf is the major organ involved in light perception and conversion of solar energy into organic carbon. In order to adapt to different natural habitats, plants have developed a variety of leaf forms, ranging from simple to compound, with various forms of dissection. Due to the enormous cellular complexity of leaves, understanding the mechanisms regulating development of these organs is difficult. In recent years there has been a dramatic increase in the use of technically advanced imaging techniques and computational modeling in studies of leaf development. Additionally, molecular tools for manipulation of morphogenesis were successfully used for in planta verification of developmental models. Results of these interdisciplinary studies show that global growth patterns influencing final leaf form are generated by cooperative action of genetic, biochemical, and biomechanical inputs. This review summarizes recent progress in integrative studies on leaf development and illustrates how intrinsic features of leaves (including their cellular complexity influence the choice of experimental approach.

  6. Persimmon leaf flavonoid induces brain ischemic tolerance in mice

    Institute of Scientific and Technical Information of China (English)

    Mingsan Miao; Xuexia Zhang; Linan Wang

    2013-01-01

    The persimmon leaf has been shown to improve cerebral ischemic outcomes; however, its mechanism of action remains unclear. In this study, mice were subjected to 10 minutes of ischemic preconditioning, and persimmon leaf flavonoid was orally administered for 5 days. Results showed that the persimmon leaf flavonoid significantly improved the content of tissue type plasminogen activator and 6-keto prostaglandin-F1 α in the cerebral cortex, decreased the content of thromboxane B2, and reduced the content of plasminogen activator inhibitor-1 in mice. Following optical microscopy, persimmon leaf flavonoid was also shown to reduce cell swelling and nuclear hyperchromatism in the cerebral cortex and hippocampus of mice. These results suggested that persimmon leaf flavonoid can effectively inhibit brain thrombosis, improve blood supply to the brain, and relieve ischemia-induced pathological damage, resulting in brain ischemic tolerance.

  7. EXPERIMENTAL INVESTIGATION & NUMERICAL ANALYSIS OF COMPOSITE LEAF SPRING

    Directory of Open Access Journals (Sweden)

    K. K. JADHAO,

    2011-06-01

    Full Text Available The Automobile Industry has shown keen interest for replacement of steel leaf spring with that of glass fiber composite leaf spring, since the composite material has high strength to weight ratio, good corrosion resistance and tailor-able properties. The objective of present study was to replace material for leaf spring. In present study the material selected was glass fiber reinforced plastic (GFRP and the polyester resin (NETPOL 1011 can be used which was more economical this will reduce total cost of composite leaf spring. A spring with constant width and thickness was fabricated by hand lay-up technique which was very simple and economical. The experiments were conducted on UTM and numerical analysis was done via (FEA using ANSYS software. Stresses and deflection results were verified for analytical and experimental results. Result shows that, the composite spring has stresses much lower than steel leaf spring and weight of composite spring was nearly reduced up to 85%.

  8. Microscopic evaluation and physiochemical analysis of Dillenia indica leaf

    Institute of Scientific and Technical Information of China (English)

    S Kumar; V Kumar; Om Prakash

    2011-01-01

    Objective: To study detail microscopic evaluation and physiochemical analysis of Dillenia indica (D. indica) leaf. Methods: Fresh leaf sample and dried power of the leaf were studied macroscopically and microscopically. Preliminary phytochemical investigation of plant material was done. Other WHO recommended parameters for standardizations were also performed. Results: The detail microscopy revealed the presence of anomocytic stomata, unicellular trichome, xylem fibres, calcium oxalate crystals, vascular bundles, etc. Leaf constants such as stomatal number, stomatal index, vein-islet number and veinlet termination numbers were also measured. Physiochemical parameters such as ash values, loss on drying, extractive values, percentage of foreign matters, swelling index, etc. were also determined. Preliminary phytochemical screening showed the presence of steroids, terpenoids, glycosides, fatty acids, flavonoids, phenolic compounds and carbohydrates. Conclusions: The microscopic and physiochemical analysis of the D. indica leaf is useful in standardization for quality, purity and sample identification.

  9. METHODS OF BIOMONITORING IN URBAN ENVIRONMENT: LEAF AREA AND FRACTAL DIMENSION

    Directory of Open Access Journals (Sweden)

    Nicoleta IANOVICI

    2015-12-01

    Full Text Available In urban conditions, we investigated several leaf traits (leaf area, specific leaf area, fractal dimension and specific leaf weight on Taraxacum officinale, Tilia tomentosa, Aesculus hippocastanum and Ambrosia artemisiifolia. The analyzed organs were mature leaves, on the first indications of senescence. This study used an exact, inexpensive and efficient in terms of costs alternative methods for determining the leaf parameters. On the other hand, this paper presents an application of the leaf area and fractal dimension in the analysis of leaf shape. Our results show that leaf area and fractal dimension are sensitive parameters that can be effectively used in biomonitoring.

  10. Rapid, high-resolution measurement of leaf area and leaf orientation using terrestrial LiDAR scanning data

    Science.gov (United States)

    Leaf orientation plays a fundamental role in many transport processes in plant canopies. At the plant or stand level, leaf orientation is often highly anisotropic and heterogeneous, yet most analyses neglect such complexity. In many cases, this is due to the difficulty in measuring the spatial varia...

  11. Spatial modelling of rice yield losses in Tanzania due to bacterial leaf blight and leaf blast in a changing climate

    NARCIS (Netherlands)

    Duku, Confidence; Sparks, Adam H.; Zwart, Sander J.

    2016-01-01

    Rice is the most rapidly growing staple food in Africa and although rice production is steadily increasing, the consumption is still out-pacing the production. In Tanzania, two important diseases in rice production are leaf blast caused by Magnaporthe oryzae and bacterial leaf blight caused by

  12. Evolution of the leaf economics spectrum in herbs: Evidence from environmental divergences in leaf physiology across Helianthus (Asteraceae).

    Science.gov (United States)

    Mason, Chase M; Donovan, Lisa A

    2015-10-01

    The leaf economics spectrum (LES) describes a major axis of plant functional trait variation worldwide, defining suites of leaf traits aligned with resource-acquisitive to resource-conservative ecological strategies. The LES has been interpreted to arise from leaf-level trade-offs among ecophysiological traits common to all plants. However, it has been suggested that the defining leaf-level trade-offs of the LES may not hold within specific functional groups (e.g., herbs) nor within many groups of closely related species, which challenges the usefulness of the LES paradigm across evolutionary scales. Here, we examine the evolution of the LES across 28 species of the diverse herbaceous genus Helianthus (the sunflowers), which occupies a wide range of habitats and climate variation across North America. Using a phylogenetic comparative approach, we find repeated evolution of more resource-acquisitive LES strategies in cooler, drier, and more fertile environments. We also find macroevolutionary correlations among LES traits that recapitulate aspects of the global LES, but with one major difference: leaf mass per area is uncorrelated with leaf lifespan. This indicates that whole-plant processes likely drive variation in leaf lifespan across Helianthus, rather than leaf-level trade-offs. These results suggest that LES patterns do not reflect universal physiological trade-offs at small evolutionary scales. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

  13. Linear measurements of the leaf blade in xaraes and massai grasses for estimation of the leaf area

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    Wilton Ladeira da Silva

    2013-09-01

    Full Text Available Knowledge on the leaf area of foraging grasses is essential, since it’s one of the most important variables in the evaluation of plant growth. Thus, one aimed at determining equations which allow, through simple measurements of leaf length, as well as average and maximum width, to quickly and accurately estimate the actual leaf area of Brachiaria brizantha cv. Xaraes and Panicum maximum cv. Massai. One measured with millimeter rulers the length along the main vein (L, the maximum width perpendicular to the main vein (Wmax, and the average width (Wave of leaf blades in both species. For determining the actual leaf areas (ALA, one used the Li-Cor®, model LI 3000. Regression and correlation studies were performed between ALA and the leaf area estimated through the linear or exponential equations for choosing the best equations. For xaraes grass the equation with the best accuracy for estimating ALA was the linear 0.53+0.98 LWave and for massai grass the best options were the linear 1.30+0.92 LWave and the exponential 8.86e0.04LWmax and 10.30e0.03LWave. Estimates of the leaf area of xaraes grass and massai grass through simple measurements of leaf length and width have proved to be effective and accurate.

  14. [Leaf anatomic studies in solanaceae of Venezuela. VI. Leaf anatomy of 10 species of Cestrum L].

    Science.gov (United States)

    Jáuregui, D; de Ríos, N R; Benítez de Rojas, C E

    2001-01-01

    The leaf anatomy of Cestrum acuminatissimum Dunal, C. alternifolium (Jacq.) O.E. Schulz, C. glabrescens (C.V. Morton) Steyerm. et Maguire, C. imbricatum Rusby, C. Iatifolium Lam., C. neblinense D'Arcy et Benítez, C. ruizteranianum Benítez et D'Arcy, C. schulzianum Francey, C. tillettii Benítez et D'Arcy y C. tubulosum Sendtner, is described in order to value its diagnostic characters useful as source of data in the taxonomy of the Solanaceae. The material was obtained from specimens deposited in MY herbarium, coming from different geographical areas of Venezuela, and it was prepared according the classical methodology used in leaf anatomy studies. The results obtained have, besides the common features mentions for other species of the genus Cestrum, some differences in: types and density of trichomes, thickness and sinuousities of the cell wall, stomata position, as well as in the distribution of esclerenchymatous cells of the mesophyll, midvein petiole.

  15. [Leaf anatomy study in Solanaceae of Venezuela. V. leaf anatomy of eleven species of Cestrum L] .

    Science.gov (United States)

    Jáuregul, D; Rodriguez, N; Benítez, C E

    2000-01-01

    Leaf anatomy of the following eleven species: C. buxifolium Kunth, C. humboldtii Francey, C. lindenii Dunal, C. mariquitense Kunth, C. megalophyllum Dunal, C. olivaceum Francey, C. pariense Steyerm., C petiolare Kunth, C. scandans Vahl, C. strigilatum Ruiz et Pavón and C. tomentosum L.f. is described. Transverse sectioning, bruise and clearing according to the classical methods for optical microscopy were made. The species studied show dissimilitude in relation to a) fohar blade: thickness and sinuosity of epidermal cell walls; type, density and presence of trichornes, leaf type according the position of the stomata, thickness of both palisade and spongy parenchy-ma, number of spongy parenchyma layers, occurrence or not of paranchymatous sheath and sclerifled cells in mesophyll, tmbeculae or projection walls b) Midvein: degree of development and arrangement of the parenchyma and collenchyma, c) Petiole: size and form in transverse section, presence of ornamented cuticle, peridermis and degree of development of the sclerenctiyma next to vascular bundles.

  16. Adsorption Studies of Radish Leaf Powder

    Directory of Open Access Journals (Sweden)

    Ankita

    2016-01-01

    Full Text Available Radish leaves (Raphanus sativus powder fractions was subjected to moisture adsorption isotherms at different isothermal temperature conditions from 15-45°C with an equal interval of 10°C. The sorption data obtained in gravimetric static method under 0.11–0.90 water activity conditions were subjected for sorption isotherms and found to be typical sigmoid trend. Experimental data were assessed for the applicability in the prediction through sorption models fitting and found that Polynomial and GAB equations performed well over all fitted models in describing equilibrium moisture content – equilibrium relative humidity (EMC–ERH relationships for shelf stable dehydrated radish leaf powder, over the entire range of temperatures condition under study. The net isosteric heat of sorption, differential entropy and free energy were determined at different temperatures and their dependence was seen with respect to equilibrium moisture content.

  17. Antioxidative Activity of Tobacco Leaf Protein Hydrolysates

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    Guohua Rao

    2007-01-01

    Full Text Available Discarded tobacco leaf protein hydrolysate (DTLPH was prepared by enzymatic hydrolysis using papain and then separated using ultrafiltration (UF membranes with molecular mass cut-off (MMCO of 10, 5, 3 and 1 kDa. Four permeate fractions including 10-K, 5-K, 3-K and 1-K (the permeate fractions from 10, 5, 3 and 1 kDa hydrolysate fractions were obtained. The 5-K hydrolysate fraction had high oxidation inhibilitory ratio (42.62 %, which was about twofold higher than the original hydrolysate and as high as that of vitamin E (α-tocopherol. The fractionated hydrolysates were superior to the original hydrolysate in the antioxidative activity tested. Moreover, these separated hydrolysates showed the enhanced functional property. The amino acid composition of 5-K hydrolysate was analyzed and the results show that the high antioxidative activity of 5-K hydrolysate was derived from high content of histidine, methionine, cystine and tryptophan.

  18. Modelling transcriptional networks in leaf senescence.

    Science.gov (United States)

    Penfold, Christopher A; Buchanan-Wollaston, Vicky

    2014-07-01

    The process of leaf senescence is induced by an extensive range of developmental and environmental signals and controlled by multiple, cross-linking pathways, many of which overlap with plant stress-response signals. Elucidation of this complex regulation requires a step beyond a traditional one-gene-at-a-time analysis. Application of a more global analysis using statistical and mathematical tools of systems biology is an approach that is being applied to address this problem. A variety of modelling methods applicable to the analysis of current and future senescence data are reviewed and discussed using some senescence-specific examples. Network modelling with a senescence transcriptome time course followed by testing predictions with gene-expression data illustrates the application of systems biology tools.

  19. Scaling relationships among twig size, leaf size and leafing intensity in a successional series of subtropical forests.

    Science.gov (United States)

    Yan, En-Rong; Wang, Xi-Hua; Chang, Scott X; He, Fangliang

    2013-06-01

    Scaling relationships among twig size, leaf size and leafing intensity fundamentally influence the twig-leaf deployment pattern, a property that affects the architecture and functioning of plants. However, our understanding of how these relationships change within a species or between species as a function of forest succession is unclear. We determined log-log scaling relationships between twig cross-sectional area (twig size) and each of total and individual leaf area, and leafing intensity (the number of leaves per twig volume) for 78 woody species along a successional series in subtropical evergreen forests in eastern China. The series included four stages: secondary shrub (S1), young (S2), sub-climax (S3) and climax evergreen broadleaved forests (S4). The scaling slopes in each of the three relationships did not differ among the four stages. The y-intercept did not shift among the successional stages in the relationship between twig cross-sectional area and total leaf area; however, the y-intercept was greatest in S4, intermediate in S3 and lowest in S2 and S1 for the relationship between twig size and individual leaf area, while the opposite pattern was found for the twig size-leafing intensity relationship. This indicates that late successional trees have few but large leaves while early successional trees have more small leaves per unit twig size. For the relationship between twig cross-sectional area and total leaf area, there was no difference in the regression slope between recurrent (appear in more than one stages) and non-recurrent species (appear in only one stage) for each of the S1-S2, S2-S3 and S3-S4 pairs. A significant difference in the y-intercept was found in the S2-S3 pair only. In the relationship between twig cross-sectional area and individual leaf area, the regression slope between recurrent and non-recurrent species was homogeneous in the S1-S2 and S3-S4 pairs, but heterogeneous in the S2-S3 pair. We conclude that forest succession caused

  20. Effect of leaf surface waxes on leaf colonization by Pantoea agglomerans and Clavibacter michiganensis.

    Science.gov (United States)

    Marcell, Lise M; Beattie, Gwyn A

    2002-12-01

    To evaluate the influence of leaf cuticular waxes on bacterial colonization of leaves, bacterial colonization patterns were examined on four glossy maize (Zea mays L.) mutants that were altered in their cuticular wax biosynthesis. Mutant gl3 was indistinguishable from the wild-type maize in its ability to foster colonization by the two bacterial species, Pantoea agglomerans and Clavibacter michiganensis subsp. nebraskensis. In contrast, the other three mutants supported the development of populations that significantly differed in size from those on the wild type. Mutant gl5 gl20 supported smaller populations of P. agglomerans, but not C. michiganensis, while mutant gl1 supported larger populations of C. michiganensis but not P. agglomerans. Mutant gl4 supported larger populations of both bacterial species. The exceptional ability of mutant gl4 to support bacterial colonization was hypothesized to result from the lower density of the crystalline waxes on gl4 than on the wild type, because a reduced crystal density could promote capillary water movement and water trapping among the wax crystals. This hypothesis was supported by the demonstration that the mechanical introduction of gaps among the wax crystals of the wild-type leaves resulted in the establishment of larger P. agglomerans populations on the altered leaves. These results provide the first direct evidence that leaf surface waxes affect bacterial leaf colonization at various stages of colonization and in a bacterial species-dependent manner.

  1. Leaf miner-induced changes in leaf transmittance cause variations in insect respiration rates.

    Science.gov (United States)

    Pincebourde, Sylvain; Casas, Jérôme

    2006-02-01

    Very little is known about alterations in microclimate when an herbivore feeds on host plant. Modifications of leaf transmittance properties induced by feeding activity of the leaf miner Phyllonorycter blancardella F. were measured using a spectrometer. Their effects on the herbivore's body temperature and respiration rate have been determined under controlled conditions and varying radiation level employing an infrared gas analyser. By feeding within leaf tissues, a miner induces the formation of feeding windows which transmit a large portion of incoming radiations within a mine. As a result, body temperature and respiration rate increase with radiation level when positioned below feeding windows. Therefore, the miner is not always protected from radiations despite living within plant tissues. The amount of CO(2) released by larvae below feeding windows at high radiation levels is about five-fold that recorded in the dark. By contrast, body temperature and respiration rate increase only slightly with radiation level when the insect is positioned below intact tissues through which radiation is only weakly transmitted. A mine offers its inhabitant a heterogeneous light environment that allows the insect larva to thermoregulate through behavioural modification. Our results highlight the importance of physical feedbacks induced by herbivory which alter significantly an insect's metabolism independently of its nutritional state.

  2. PROXIMATE CONTENT AND CHEMICAL COMPOSITION OF OCIMUM VIRIDIS LEAF AND OCIMUM GRATISSIUM LEAF

    Directory of Open Access Journals (Sweden)

    Abdurahman F.I.

    2012-04-01

    Full Text Available This study is aimed at determining the proximate content, concentration of some micro/macro elements and the phytochemistry of Ocimum viridis (scent leafs and Ocimum gratissimum (jaw’s mallow leafs with the view of updating its usage in orthodox and herbal medicine by man in the treatment of dysentery, diarrhea and wound healing. The leaves sampled of Ocimum viridis and Ocimum gratissimum were collected from Zannari, Jere L.G.A, Borno state, Nigeria. The proximate analysis was carried out using methods of Association of Analytical Chemist and the results showed that Ocimum viridis has higher dry matter (99.70%, crude protein (12.48%, Nitrogen free extract (2.03%, Ash (6.5% and fats (7.0%. While carbohydrate (83.40%, crude fibre (45.50% and moisture content (0.4% were estimated to be higher in Ocimum gratissimum. The levels of eight (8 elements (Ca, F, Cu, Cr, Mn, Zn, Fe, and Pb were determined using Atomic Absorption Spectrophotometry. The results revealed higher concentration in Ocimum gratissimum except for iron and manganese concentration which are higher of the elements understudy in Ocimum viridis only the lead was not detected in the samples by the methodology employed for the analysis. The concentration of anions (nitrates, phosphates and sulphates was estimated using the Smart Spectro Spectrophotometer. It shows that, Ocimum viridis has higher concentration of 11.08 mg/g and 7.04 mg/g in nitrates and sulphates respectively. And Ocimum gratissimum has higher concentration of phosphates 6.28 mg/g. The phytochemicals and some heavy and trace elements as well as a few anions were evaluated using standard procedures. The phytochemical screening of both the fresh and dry leafs revealed the presence of very high cardiac glycosides and the flavonoids, terpenoids, saponins, tannins and carbohydrates shows difference in variation of the leafs. And alkaloids were found to be absence in both fresh and dry leafs. The elemental content obtained

  3. Estimation of leaf area with an integrating sphere.

    Science.gov (United States)

    Serrano, Lydia; Gamon, J. A.; Berry, J.

    1997-01-01

    Relative absorptance of intact branches measured with an integrating sphere was compared to leaf area estimated by conventional methods (volume displacement and scanning area meter) for three conifer species: Picea mariana (Mill.) BSP, Pinus banksiana (Lamb.) and Pseudotsuga menziesii (Mirb.) Franco. A consistent relationship between relative absorptance and surface area emerged for the three species. The ability to predict leaf area from absorptance was further explored by measuring branches of Pseudotsuga menziesii grown in varying light and nutrient regimes. When a single equation was used to predict leaf area under all growth conditions, errors were as large as 40% primarily because of variation in leaf absorptivity, with the largest errors associated with extremely nutrient-deficient foliage. When separate empirical equations were developed for each growth treatment, predicted leaf surface area agreed to within 5% of the area determined by the volume displacement method. Leaf surface area estimated from theoretical principles was also in good agreement with total surface area estimated independently by conventional methods. With proper accounting for needle absorptivity, which varied with growth conditions, leaf area estimates obtained by the integrating sphere method were of similar accuracy to those obtained by conventional methods, with the added advantage that the method allowed intact foliage to be sampled nondestructively in the field. Because the integrating sphere method preserves branch structure during measurement, it could provide a useful measure of needle area for photosynthetic or developmental studies requiring repeated sampling of the same branch.

  4. TALE and Shape: How to Make a Leaf Different

    Directory of Open Access Journals (Sweden)

    Elisabetta Di Giacomo

    2013-05-01

    Full Text Available The Three Amino acid Loop Extension (TALE proteins constitute an ancestral superclass of homeodomain transcription factors conserved in animals, plants and fungi. In plants they comprise two classes, KNOTTED1-LIKE homeobox (KNOX and BEL1-like homeobox (BLH or BELL, hereafter referred to as BLH, which are involved in shoot apical meristem (SAM function, as well as in the determination and morphological development of leaves, stems and inflorescences. Selective protein-protein interactions between KNOXs and BLHs affect heterodimer subcellular localization and target affinity. KNOXs exert their roles by maintaining a proper balance between undifferentiated and differentiated cell state through the modulation of multiple hormonal pathways. A pivotal function of KNOX in evolutionary diversification of leaf morphology has been assessed. In the SAM of both simple- and compound-leafed seed species, downregulation of most class 1 KNOX (KNOX1 genes marks the sites of leaf primordia initiation. However, KNOX1 expression is re-established during leaf primordia development of compound-leafed species to maintain transient indeterminacy and morphogenetic activity at the leaf margins. Despite the increasing knowledge available about KNOX1 protein function in plant development, a comprehensive view on their downstream effectors remains elusive. This review highlights the role of TALE proteins in leaf initiation and morphological plasticity with a focus on recent advances in the identification of downstream target genes and pathways.

  5. Revealing catastrophic failure of leaf networks under stress.

    Science.gov (United States)

    Brodribb, Timothy J; Bienaimé, Diane; Marmottant, Philippe

    2016-04-26

    The intricate patterns of veins that adorn the leaves of land plants are among the most important networks in biology. Water flows in these leaf irrigation networks under tension and is vulnerable to embolism-forming cavitations, which cut off water supply, ultimately causing leaf death. Understanding the ways in which plants structure their vein supply network to protect against embolism-induced failure has enormous ecological and evolutionary implications, but until now there has been no way of observing dynamic failure in natural leaf networks. Here we use a new optical method that allows the initiation and spread of embolism bubbles in the leaf network to be visualized. Examining embolism-induced failure of architecturally diverse leaf networks, we found that conservative rules described the progression of hydraulic failure within veins. The most fundamental rule was that within an individual venation network, susceptibility to embolism always increased proportionally with the size of veins, and initial nucleation always occurred in the largest vein. Beyond this general framework, considerable diversity in the pattern of network failure was found between species, related to differences in vein network topology. The highest-risk network was found in a fern species, where single events caused massive disruption to leaf water supply, whereas safer networks in angiosperm leaves contained veins with composite properties, allowing a staged failure of water supply. These results reveal how the size structure of leaf venation is a critical determinant of the spread of embolism damage to leaves during drought.

  6. Analysis of Composite Leaf Spring Enhanced With Nanoparticles

    Directory of Open Access Journals (Sweden)

    K. Ganesan

    2015-12-01

    Full Text Available Weight reduction is now the main issue in automobile industries. In this work due to reduce the weight of steel spring with composite leaf spring due to high strength ratio is need to improve. The main aim is to compare to the load carrying capacity, stiffness and weight savings of composite leaf spring with that of steel leaf spring at rated-load and over-load condition. The analysis has been carried out for the leaf spring made up of steel and Composite materials. Composite specimens are fabricated with two different staking sequences like the (resin with clay and enhanced with Nanoparticles. The thickness and width for constant cross section is maintained on the moulding techniques. The design of multi leaf spring was modeled in PRO-E and imported in ANSYS 14.5.the dimensions of an existing multi leaf spring is taken for modeling and analysis of a laminated composite multi leaf spring with different composite sequence materials subjected to the same load as that of steel spring.

  7. Importance of Secondary Metabolites for Leaf Beetles (Coleoptera: Chrysomelidae

    Directory of Open Access Journals (Sweden)

    A. N. EKİZ

    2014-06-01

    Full Text Available Leaf beetles (Chrysomelidae are one of the most diverse families of herbivorous insects. Many of them are important agricultural pests and cause remarkable loss of crop and money as well. Plant leaves and roots are primary food source of both larva and adults of leaf beetles. Plants produce many secondary metabolites in reaction to herbivore insects. It is a well-known phenomenon that quantity and variety of secondary metabolites in plant leaves may change in response to insect attacks. Herbivore insects have to deal with such defensive secondary chemicals and overcome either by detoxifying or storing them. Accordingly, many specialist herbivores coevolved with their host plant. Certain phenolic glycosides may reduce leaf beetle feeding. Condensed tannins are anti-herbivore defenses against leaf chewing beetles, including leaf beetles. Flavonoid compounds are feeding deterrents for many flea leaf beetles. Cinnamic acid derivatives are other known feeding deterrents for leaf beetles. Secondary metabolites quantity and nutritional quality of host plants are not only important for feeding but also for providing enemy-free space and suitable oviposition sites.

  8. TALE and Shape: How to Make a Leaf Different.

    Science.gov (United States)

    Di Giacomo, Elisabetta; Iannelli, Maria Adelaide; Frugis, Giovanna

    2013-05-06

    The Three Amino acid Loop Extension (TALE) proteins constitute an ancestral superclass of homeodomain transcription factors conserved in animals, plants and fungi. In plants they comprise two classes, KNOTTED1-LIKE homeobox (KNOX) and BEL1-like homeobox (BLH or BELL, hereafter referred to as BLH), which are involved in shoot apical meristem (SAM) function, as well as in the determination and morphological development of leaves, stems and inflorescences. Selective protein-protein interactions between KNOXs and BLHs affect heterodimer subcellular localization and target affinity. KNOXs exert their roles by maintaining a proper balance between undifferentiated and differentiated cell state through the modulation of multiple hormonal pathways. A pivotal function of KNOX in evolutionary diversification of leaf morphology has been assessed. In the SAM of both simple- and compound-leafed seed species, downregulation of most class 1 KNOX (KNOX1) genes marks the sites of leaf primordia initiation. However, KNOX1 expression is re-established during leaf primordia development of compound-leafed species to maintain transient indeterminacy and morphogenetic activity at the leaf margins. Despite the increasing knowledge available about KNOX1 protein function in plant development, a comprehensive view on their downstream effectors remains elusive. This review highlights the role of TALE proteins in leaf initiation and morphological plasticity with a focus on recent advances in the identification of downstream target genes and pathways.

  9. The use of latent class analysis to estimate the sensitivities and specificities of diagnostic tests for Squash vein yellowing virus in cucurbit species when there is no gold standard.

    Science.gov (United States)

    Turechek, William W; Webster, Craig G; Duan, Jingyi; Roberts, Pamela D; Kousik, Chandrasekar S; Adkins, Scott

    2013-12-01

    better sensitivity but poorer specificity for diagnosing SqVYV infection in crown tissue than it did in vine tissue, whereas symptoms had very poor sensitivity but excellent specificity in both tissues for all cucurbits analyzed in this study. Test performance also varied with habitat and genus but not with distance from the crown. The results given here provide quantitative measurements of test performance for a range of conditions and provide the information needed to interpret test results when tests are used in parallel or serial combination for a diagnosis.

  10. Scaling up stomatal conductance from leaf to canopy using a dual-leaf model for estimating crop evapotranspiration.

    Directory of Open Access Journals (Sweden)

    Risheng Ding

    Full Text Available The dual-source Shuttleworth-Wallace model has been widely used to estimate and partition crop evapotranspiration (λET. Canopy stomatal conductance (Gsc, an essential parameter of the model, is often calculated by scaling up leaf stomatal conductance, considering the canopy as one single leaf in a so-called "big-leaf" model. However, Gsc can be overestimated or underestimated depending on leaf area index level in the big-leaf model, due to a non-linear stomatal response to light. A dual-leaf model, scaling up Gsc from leaf to canopy, was developed in this study. The non-linear stomata-light relationship was incorporated by dividing the canopy into sunlit and shaded fractions and calculating each fraction separately according to absorbed irradiances. The model includes: (1 the absorbed irradiance, determined by separately integrating the sunlit and shaded leaves with consideration of both beam and diffuse radiation; (2 leaf area for the sunlit and shaded fractions; and (3 a leaf conductance model that accounts for the response of stomata to PAR, vapor pressure deficit and available soil water. In contrast to the significant errors of Gsc in the big-leaf model, the predicted Gsc using the dual-leaf model had a high degree of data-model agreement; the slope of the linear regression between daytime predictions and measurements was 1.01 (R2 = 0.98, with RMSE of 0.6120 mm s-1 for four clear-sky days in different growth stages. The estimates of half-hourly λET using the dual-source dual-leaf model (DSDL agreed well with measurements and the error was within 5% during two growing seasons of maize with differing hydrometeorological and management strategies. Moreover, the estimates of soil evaporation using the DSDL model closely matched actual measurements. Our results indicate that the DSDL model can produce more accurate estimation of Gsc and λET, compared to the big-leaf model, and thus is an effective alternative approach for estimating and

  11. Plasticity in sunflower leaf and cell growth under high salinity.

    Science.gov (United States)

    Céccoli, G; Bustos, D; Ortega, L I; Senn, M E; Vegetti, A; Taleisnik, E

    2015-01-01

    A group of sunflower lines that exhibit a range of leaf Na(+) concentrations under high salinity was used to explore whether the responses to the osmotic and ionic components of salinity can be distinguished in leaf expansion kinetics analysis. It was expected that at the initial stages of the salt treatment, leaf expansion kinetics changes would be dominated by responses to the osmotic component of salinity, and that later on, ion inclusion would impose further kinetics changes. It was also expected that differential leaf Na(+) accumulation would be reflected in specific changes in cell division and expansion rates. Plants of four sunflower lines were gradually treated with a relatively high (130 mm NaCl) salt treatment. Leaf expansion kinetics curves were compared in leaves that were formed before, during and after the initiation of the salt treatment. Leaf areas were smaller in salt-treated plants, but the analysis of growth curves did not reveal differences that could be attributed to differential Na(+) accumulation, since similar changes in leaf expansion kinetics were observed in lines with different magnitudes of salt accumulation. Nevertheless, in a high leaf Na(+) -including line, cell divisions were affected earlier, resulting in leaves with proportionally fewer cells than in a Na(+) -excluding line. A distinct change in leaf epidermal pavement shape caused by salinity is reported for the first time. Mature pavement cells in leaves of control plants exhibited typical lobed, jigsaw-puzzle shape, whereas in treated plants, they tended to retain closer-to-circular shapes and a lower number of lobes.

  12. Optimal leaf positions for chlorophyll meter measurement in rice

    Directory of Open Access Journals (Sweden)

    Zhaofeng eYuan

    2016-05-01

    Full Text Available The Soil Plant Analysis Development (SPAD chlorophyll meter is one of the most commonly used diagnostic tools to measure crop nitrogen status. However, the measurement method of the meter could significantly affect the accuracy of the final estimation. Thus, this research was undertaken to develop a new methodology to optimize SPAD meter measurements in rice (Oryza sativa L.. A flatbed color scanner was used to map the dynamic chlorophyll distribution and irregular leaf shapes. Calculus algorithm was adopted to estimate the potential positions for SPAD meter measurement along the leaf blade. Data generated by the flatbed color scanner and SPAD meter were analysed simultaneously. The results suggested that a position 2/3 of the distance from the leaf base to the apex (2/3 position could represent the chlorophyll content of the entire leaf blade, as indicated by the relatively low variance of measurements at that positon. SPAD values based on di-positional leaves and the extracted chlorophyll a and b contents were compared. This comparison showed that the 2/3 position on the lower leaves tended to be more sensitive to changes in chlorophyll content. Finally, the 2/3 position and average SPAD values of the fourth fully expanded leaf from the top were compared with leaf nitrogen concentration. The results showed the 2/3 position on that leaf was most suitable for predicting the nitrogen status of rice. Based on these results, we recommend making SPAD measurements at the 2/3 position on the fourth fully expanded leaf from the top. The coupling of dynamic chlorophyll distribution and irregular leaf shapes information can provide a promising approach for the calibration of SPAD meter measurement, which can further benefit the in situ nitrogen management by providing reliable estimation of crops nitrogen nutrition status.

  13. Olive leaf extract inhibits lead poisoning-induced brain injury**

    Institute of Scientific and Technical Information of China (English)

    Yu Wang; Shengqing Wang; Wenhui Cui; Jiujun He; Zhenfu Wang; Xiaolu Yang

    2013-01-01

    Olive leaves have an antioxidant capacity, and olive leaf extract can protect the blood, spleen and hippocampus in lead-poisoned mice. However, little is known about the effects of olive leaf extract on lead-induced brain injury. This study was designed to determine whether olive leaf extract can inhibit lead-induced brain injury, and whether this effect is associated with antioxidant capacity. First, we established a mouse model of lead poisoning by continuous intragastric administration of lead acetate for 30 days. Two hours after successful model establishment, lead-poisoned mice were given olive leaf extract at doses of 250, 500 or 1 000 mg/kg daily by intragastric administration for 50 days. Under the transmission electron microscope, olive leaf extract attenuated neuronal and capil ary injury and reduced damage to organel es and the matrix around the capil aries in the frontal lobe of the cerebral cortex in the lead-poisoned mice. Olive leaf extract at a dose of 1 000 mg/kg had the greatest protective effect. Spectrophotometry showed that olive leaf extract significantly in-creased the activities of superoxide dismutase, catalase, alkaline phosphatase and acid phospha-tase, while it reduced malondialdehyde content, in a dose-dependent manner. Furthermore, im-munohistochemical staining revealed that olive leaf extract dose-dependently decreased Bax pro-tein expression in the cerebral cortex of lead-poisoned mice. Our findings indicate that olive leaf extract can inhibit lead-induced brain injury by increasing antioxidant capacity and reducing apop-tosis.

  14. Changes in Endopeptidase Activity during Photosynthetic Declination in Rice Leaf

    Institute of Scientific and Technical Information of China (English)

    DENGZhi-rui; ZHANGRong-xian

    2004-01-01

    Two japonica rice varieties, Wuyujing 3 and 97-7, were used to study the changes in contents of soluble protein, free amino acids and endopeptidase activity, during photosynthetic declination. The content of soluble protein in flag leaf of cv.Wuyujing 3 was higher than that of cv. 97-7, but decreased rapidly in Wuyujing 3. Free amino acids in flag leaf and the thirteenth leaf of Wuyujing 3 started to increase 10 days before the turning point of photosynthetic declination (TPPD), while it occurred just 1-2 days before TPPD in the flag leaf and the thirteenth leaf of 97-7. During reversible phase of photosynthetic declination,endopeptidase activity remained at a low level and increased slightly only in the later part of this phase. Then it rose up rapidly at irreversible decline phase and reached a vety high level. For Wuyujing 3, the change in endopeptidase activity in the thirteenth leaf was parallel to that in flag leaf. However, for 97-7, the rapid increase of endopeptidase activity in the thirteenth leaf started later than that of flag leaf. The results implied that the rate of protein breakdown and conversion to transportable nitrogen in leaves of 97-7 was slower than that in leaves of Wuyujing 3 during photosynthetic declination and it led to relativeh" lower seed setting rate and fully filling grains rate in 97-7. This may be one of the important reasons why 97-7 could not bring the high yicld potentiality into play and the findings may be taken into consideration while breeding for high potential varieties in future.

  15. Changes in Endopeptidase Activity during Photosynthetic Declination in Rice Leaf

    Institute of Scientific and Technical Information of China (English)

    DENG Zhi-rui; ZHANG Rong-xian

    2004-01-01

    Two japonica rice varieties, Wuyujing 3 and 97-7, were used to study the changes in contents of soluble protein, free amino acids and endopeptidase activity during photosynthetic declination. The content of soluble protein in flag leaf of cv.Wuyujing 3 was higher than that of cv. 97-7, but decreased rapidly in Wuyujing 3. Free amino acids in flag leaf and the thirteenth leaf of Wuyujing 3 started to increase 10 days before the turning point of photosynthetic declination (TPPD), while it occurred just 1-2 days before TPPD in the flag leaf and the thirteenth leaf of 97-7. During reversible phase of photosynthetic declination,endopeptidase activity remained at a low level and increased slightly only in the later part of this phase. Then it rose up rapidly at irreversible decline phase and reached a very high level. For Wuyujing 3, the change in endopeptidase activity in the thirteenth leaf was parallel to that in flag leaf. However, for 97-7, the rapid increase of endopeptidase activity in the thirteenth leaf started later than that of flag leaf. The results implied that the rate of protein breakdown and conversion to transportable nitrogen in leaves of 97-7 was slower than that in leaves of Wuyujing 3 during photosynthetic declination and it led to relatively lower seed setting rate and fully filling grains rate in 97-7. This may be one of the important reasons why 97-7 could not bring the high yield potentiality into play and the findings may be taken into consideration while breeding for high potential varieties in future.

  16. Leaf application of silicic acid to upland rice and corn

    Directory of Open Access Journals (Sweden)

    Carlos Alexandre Costa Crusciol

    2013-12-01

    Full Text Available This study aimed to evaluate the effect of Si (stabilized silicic acid, Silamol® leaf application on mineral nutrition and yield in upland rice and corn crops. The treatments were the control (without Si and Si foliar split spraying using 2 L ha-1 of the Silamol® commercial product, with 0.8% soluble Si as concentrated stabilized silicic acid. Silicon leaf application increased the concentrations of K, Ca and Si in rice and corn leaves, the number of panicles per m2 of rice and the number of grains per ear of corn; accordingly, the Si leaf application provided a higher grain yield in both crops.

  17. The action spectrum in chloroplast translocation in multilayer leaf cells

    Directory of Open Access Journals (Sweden)

    Zbigniew Lechowski

    2015-01-01

    Full Text Available By measurement of light transmittance through a leaf as criterion of chloroplast translocation, the action spectrum of Ajuga reptans was established. In the spectrum obtained, a correction was introduced for leaf autoabsorption calculated on the basis of the Beer-Lambert law. The action spectrum has two maxima: at λ= 375 nm and λ= 481 nm. The range above 502 nm has no significant effect on chloroplast translocation. Comparison with other objects examined demonstrated that in multilayer leaf cells riboflavin seems also to be a photoreceptor active in this process.

  18. Leaf Area Adjustment As an Optimal Drought-Adaptation Strategy

    Science.gov (United States)

    Manzoni, S.; Beyer, F.; Thompson, S. E.; Vico, G.; Weih, M.

    2014-12-01

    Leaf phenology plays a major role in land-atmosphere mass and energy exchanges. Much work has focused on phenological responses to light and temperature, but less to leaf area changes during dry periods. Because the duration of droughts is expected to increase under future climates in seasonally-dry as well as mesic environments, it is crucial to (i) predict drought-related phenological changes and (ii) to develop physiologically-sound models of leaf area dynamics during dry periods. Several optimization criteria have been proposed to model leaf area adjustment as soil moisture decreases. Some theories are based on the plant carbon (C) balance, hypothesizing that leaf area will decline when instantaneous net photosynthetic rates become negative (equivalent to maximization of cumulative C gain). Other theories draw on hydraulic principles, suggesting that leaf area should adjust to either maintain a constant leaf water potential (isohydric behavior) or to avoid leaf water potentials with negative impacts on photosynthesis (i.e., minimization of water stress). Evergreen leaf phenology is considered as a control case. Merging these theories into a unified framework, we quantify the effect of phenological strategy and climate forcing on the net C gain over the entire growing season. By accounting for the C costs of leaf flushing and the gains stemming from leaf photosynthesis, this metric assesses the effectiveness of different phenological strategies, under different climatic scenarios. Evergreen species are favored only when the dry period is relatively short, as they can exploit most of the growing season, and only incur leaf maintenance costs during the short dry period. In contrast, deciduous species that lower maintenance costs by losing leaves are advantaged under drier climates. Moreover, among drought-deciduous species, isohydric behavior leads to lowest C gains. Losing leaves gradually so as to maintain a net C uptake equal to zero during the driest period in

  19. Leaf hydraulic conductance declines in coordination with photosynthesis, transpiration and leaf water status as soybean leaves age regardless of soil moisture.

    Science.gov (United States)

    Locke, Anna M; Ort, Donald R

    2014-12-01

    Photosynthesis requires sufficient water transport through leaves for stomata to remain open as water transpires from the leaf, allowing CO2 to diffuse into the leaf. The leaf water needs of soybean change over time because of large microenvironment changes over their lifespan, as leaves mature in full sun at the top of the canopy and then become progressively shaded by younger leaves developing above. Leaf hydraulic conductance (K(leaf)), a measure of the leaf's water transport capacity, can often be linked to changes in microenvironment and transpiration demand. In this study, we tested the hypothesis that K(leaf) would decline in coordination with transpiration demand as soybean leaves matured and aged. Photosynthesis (A), stomatal conductance (g(s)) and leaf water potential (Ψ(leaf)) were also measured at various leaf ages with both field- and chamber-grown soybeans to assess transpiration demand. K(leaf) was found to decrease as soybean leaves aged from maturity to shading to senescence, and this decrease was strongly correlated with midday A. Decreases in K(leaf) were further correlated with decreases in g(s), although the relationship was not as strong as that with A. Separate experiments investigating the response of K(leaf) to drought demonstrated no acclimation of K(leaf) to drought conditions to protect against cavitation or loss of g(s) during drought and confirmed the effect of leaf age in K(leaf) observed in the field. These results suggest that the decline of leaf hydraulic conductance as leaves age keeps hydraulic supply in balance with demand without K(leaf)becoming limiting to transpiration water flux.

  20. Does investment in leaf defenses drive changes in leaf economic strategy? A focus on whole-plant ontogeny.

    Science.gov (United States)

    Mason, Chase M; Donovan, Lisa A

    2015-04-01

    Leaf defenses have long been studied in the context of plant growth rate, resource availability, and optimal investment theory. Likewise, one of the central modern paradigms of plant ecophysiology, the leaf economics spectrum (LES), has been extensively studied in the context of these factors across ecological scales ranging from global species data sets to temporal shifts within individuals. Despite strong physiological links between LES strategy and leaf defenses in structure, function, and resource investment, the relationship between these trait classes has not been well explored. This study investigates the relationship between leaf defenses and LES strategy across whole-plant ontogeny in three diverse Helianthus species known to exhibit dramatic ontogenetic shifts in LES strategy, focusing primarily on physical and quantitative chemical defenses. Plants were grown under controlled environmental conditions and sampled for LES and defense traits at four ontogenetic stages. Defenses were found to shift strongly with ontogeny, and to correlate strongly with LES strategy. More advanced ontogenetic stages with more conservative LES strategy leaves had higher tannin activity and toughness in all species, and higher leaf dry matter content in two of three species. Modeling results in two species support the conclusion that changes in defenses drive changes in LES strategy through ontogeny, and in one species that changes in defenses and LES strategy are likely independently driven by ontogeny. Results of this study support the hypothesis that leaf-level allocation to defenses might be an important determinant of leaf economic traits, where high investment in defenses drives a conservative LES strategy.

  1. Leaf extraction and analysis framework graphical user interface: segmenting and analyzing the structure of leaf veins and areoles.

    Science.gov (United States)

    Price, Charles A; Symonova, Olga; Mileyko, Yuriy; Hilley, Troy; Weitz, Joshua S

    2011-01-01

    Interest in the structure and function of physical biological networks has spurred the development of a number of theoretical models that predict optimal network structures across a broad array of taxonomic groups, from mammals to plants. In many cases, direct tests of predicted network structure are impossible given the lack of suitable empirical methods to quantify physical network geometry with sufficient scope and resolution. There is a long history of empirical methods to quantify the network structure of plants, from roots, to xylem networks in shoots and within leaves. However, with few exceptions, current methods emphasize the analysis of portions of, rather than entire networks. Here, we introduce the Leaf Extraction and Analysis Framework Graphical User Interface (LEAF GUI), a user-assisted software tool that facilitates improved empirical understanding of leaf network structure. LEAF GUI takes images of leaves where veins have been enhanced relative to the background, and following a series of interactive thresholding and cleaning steps, returns a suite of statistics and information on the structure of leaf venation networks and areoles. Metrics include the dimensions, position, and connectivity of all network veins, and the dimensions, shape, and position of the areoles they surround. Available for free download, the LEAF GUI software promises to facilitate improved understanding of the adaptive and ecological significance of leaf vein network structure.

  2. Controlled crumpling of graphene oxide films for tunable optical transmittance.

    Science.gov (United States)

    Thomas, Abhay V; Andow, Brandon C; Suresh, Shravan; Eksik, Osman; Yin, Jie; Dyson, Anna H; Koratkar, Nikhil

    2015-06-01

    The delamination buckling approach provides a facile means to dynamically control the optical transmittance of extremely flexible and stretchable graphene oxide coatings with fast response time. Such graphene oxide coatings can be deposited by scalable solution-processing methods for potential applications in dynamic glazing.

  3. Leaf-age effects on seasonal variability in photosynthetic parameters and its relationships with leaf mass per area and leaf nitrogen concentration within a Pinus densiflora crown.

    Science.gov (United States)

    Han, Qingmin; Kawasaki, Tatsuro; Nakano, Takashi; Chiba, Yukihiro

    2008-04-01

    In the temperate zone of Japan, Pinus densiflora Sieb. et Zucc. bears needles of up to three age classes in the upper crown and up to five age classes in the lower crown. To elucidate the effects of leaf age on photosynthetic parameters and its relationships with leaf mass per unit area (LMA) and leaf nitrogen (N(l)) concentration on an area (N(a)) and mass (N(m)) basis, we measured seasonal variations in LMA, N(l), light-saturated photosynthetic rate (A(max)), stomatal conductance (g(s)), maximum rate of carboxylation (V(cmax)) and maximum rate of electron transport (J(max)) in leaves of all age classes in the upper and lower crown. Leaf mass per unit area increased by 27% with increasing leaf age in the lower crown, but LMA did not depend on age in the upper crown. Leaf age had a significant effect on N(m) but not on N(a) in both crown positions, indicating that decreases in N(m) resulted from dilution. Photosynthetic parameters decreased significantly with leaf age in the lower crown (39% for A(max) and 43% for V(cmax)), but the effect of leaf age was not as great in the upper crown, although these parameters exhibited seasonal variation in both crown positions. Regression analysis indicated a close relationship between LMA and N(a), regardless of age class or when each age class was pooled (r(2) = 0.57-0.86). Relationships between LMA and N(a) and among A(max), V(cmax) and J(max) were weak or not significant when all age classes were examined by regression analysis. However, compared with older leaves, relationships among LMA, N(a) and A(max) were stronger in younger leaves. These results indicate that changes in LMA and N(l) mainly reflect light acclimation during leaf development, but they are only slightly affected by irradiance in mature leaves. In conclusion, LMA and N(l) are useful parameters for estimating photosynthetic capacity, but age-related effects need to be taken into account, especially in evergreen conifers.

  4. 7 CFR 28.521 - Application of color and leaf grade standards.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Application of color and leaf grade standards. 28.521... Explanatory Terms § 28.521 Application of color and leaf grade standards. American Pima cotton which in color... the color standard irrespective of the leaf content. American Pima cotton which in leaf is within...

  5. 77 FR 19278 - Leaf River Energy Center LLC; Notice of Application

    Science.gov (United States)

    2012-03-30

    ... Energy Regulatory Commission Leaf River Energy Center LLC; Notice of Application On March 20, 2012, Leaf River Energy Center LLC (Leaf River), 53 Riverside Avenue, Westport, Connecticut 06880, filed with the...-000, to authorize Leaf River to reallocate the aggregate total facility certificated storage...

  6. 76 FR 80278 - Revision of Cotton Classification Procedures for Determining Cotton Leaf Grade

    Science.gov (United States)

    2011-12-23

    ... for Determining Cotton Leaf Grade AGENCY: Agricultural Marketing Service, USDA. ACTION: Proposed rule... official leaf grade for Upland and Pima cotton. The leaf grade is a part of the official classification.... Currently, the leaf grade is determined by visual examination and comparison to the Official...

  7. Leaf traits are good predictors of plant performance across 53 rain forest species

    NARCIS (Netherlands)

    Poorter, L.; Bongers, F.J.J.M.

    2006-01-01

    We compared the leaf traits and plant performance of 53 co-occurring tree species in a semi-evergreen tropical moist forest community. The species differed in all leaf traits analyzed: leaf life span varied 11-fold among species, specific leaf area 5-fold, mass-based nitrogen 3-fold, mass-based assi

  8. 7 CFR 29.2437 - Heavy Leaf (B Group).

    Science.gov (United States)

    2010-01-01

    ... Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER... tolerance. B3M Good Mixed Color Heavy Leaf. Medium to heavy body, mature, firm, oily, semielastic, normal...

  9. 7 CFR 29.2663 - Thin Leaf (C Group).

    Science.gov (United States)

    2010-01-01

    ... Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER..., 60 percent uniform, and 40 percent injury tolerance. C3M Good Mixed Color or Variegated Thin Leaf...

  10. Evaluating a tobacco leaf humidification system involving nebulisation

    Directory of Open Access Journals (Sweden)

    Néstor Enrique Cerquera Peña

    2010-06-01

    Full Text Available A tobacco leaf humidifying system involving nebulisation was designned, implemented and evaluated; it had a system for monitoring and recording environmental conditions thereby producing an environment having more homogeneous relative humidity, ensuring better water use, better control of relative humidity and better control in managing cured tobacco leaf moisture content, thereby leading to a consequent improvement in final product quality. 55% to 75% relative humidity and 4 to 6 hour working ranges were obtained to en- sure leaf humidification reached 16% humidity on a wet basis. Two new designs are proposed for the conditioning stage regarding this conditioning chamber’s operational management, based on the results and field observations, which would allow better leaf management, thereby avoiding the risk of losses due to manipulation and over-humidification. This work strengthens research in the field of tobacco pos- tharvest technology, complementing other research projects which have been carried out in Colombia.

  11. Characterization of Leaf Photosynthetic Properties for No-Tillage Rice

    Institute of Scientific and Technical Information of China (English)

    CHEN Song; XIA Guo-mian; ZHAO Wei-ming; WU Fei-bo; ZHANG Guo-ping

    2007-01-01

    A study was conducted to determine the influence of no-tillage cultivation on leaf photosynthesis of rice plants under field conditions. Experiments with the treatments, no-tillage and conventional tillage were carried out at three locations (Jiaxing, Hangzhou,and Xiaoshan, Zhejiang Province, China) for two years (2005 and 2006). Grain yield was constant in Jiaxing, but slightly higher in Hangzhou and Xiaoshan under no-tillage cultivation than that under conventional cultivation. In comparison with the conventional cultivation, no-tillage cultivation showed less biomass accumulation before heading and higher capacity of matter production during grain filling. A significantly higher leaf net photosynthetic rate was observed for the plants under no-tillage than for those under conventional tillage. The fluorescence parameter (Fv/Fm) in leaf did not show any difference between the two cultivations. The effect of cultivation management on transpiration rate (Tr) and SPAD value of rice leaf was dependent on the location and year.

  12. Soome maiustustetootja Leaf saab peatselt uue omaniku / Tõnis Arnover

    Index Scriptorium Estoniae

    Arnover, Tõnis, 1952-

    2004-01-01

    Hollandi kontsern CSM otsustas loobuda maiustusetootmisest, sh. Soome magusatootjast Leaf ning keskenduda pagaritööstustoorme, biokemikaalide ning suhkrutoodete valmistamisele. Diagramm: CSMi kasumlikkus vähenes. Vt. samas: Eestis menukad kurgupastillid

  13. phytochemical properties and antibacterial activities of the leaf and ...

    African Journals Online (AJOL)

    DR. AMINU

    2Department of Medical Microbiology, Ahmadu Bello University Teaching Hospital, Zaria, NIGERIA ... World Health Organization ..... Table 2: Phytochemical characteristics of the leaf and latex extracts of Calotropis procera. Ingredient. Ethanol.

  14. Antibacterial activity of mangrove leaf extracts against human pathogens

    Digital Repository Service at National Institute of Oceanography (India)

    Sahoo, G.; Mulla, N.S.S.; Ansari, Z.A.; Mohandass, C.

    The antibacterial activity of leaf extract of mangroves, namely, Rhizophora mucronata, Sonneratia alba and Exoecaria agallocha from Chorao island, Goa was investigated against human bacterial pathogens Staphylococcus aureus, Streptococcus sp...

  15. Genetic resistance of maize inbred lines to anthracnose leaf blight

    Directory of Open Access Journals (Sweden)

    Hellen Christine Prochno

    2016-03-01

    Full Text Available The objectives of this study were to evaluate the resistance of maize inbred lines to anthracnose leaf blight (Colletotrichum graminicola Ces., and to estimate genetic parameters associated with resistance. Sixteen lines (S5 were evaluated for resistance to anthracnose leaf blight in three experiments, in a randomized block design with four replications. From three evaluations of severity, it was estimated the area under the disease progress curve (AUDPC, and the genetic parameters associated with resistance. Results showed the existence of genetic variability for resistance to anthracnose leaf blight in the set of studied lines. Five lines stood out for the high resistance pattern to anthracnose leaf blight, presenting the lowest AUDPC values in the three experiments, and thus were considered important sources of C. graminicola resistance genes. Estimates of genetic parameters indicated low participation of the environment and highlighted the possibility of genetic gains with artificial selection for resistance in this pathosystem.

  16. Phytochemical Observation on Leaf of Justicia Tranquebariesis. L.F.

    Science.gov (United States)

    Akilandeswari, S.; Mainmaran, S.; Valarmathi, R.; Kumara, S. Karpagam; Loganathan, Sundari V.

    2001-01-01

    Photochemical studies of leaf of the herbs Justicia tranquebariensis. (Acanthaceae) carried out in the presence of phytosterols, flavonoids, Glycosides and absence of triterpenoids, alkaloids, saponins tannins have been reported in this herb for the first time. PMID:22557013

  17. Effect of sunlight shielding on leaf structure and amino acids ...

    African Journals Online (AJOL)

    zino

    2013-09-04

    Sep 4, 2013 ... acids concentration of light sensitive albino tea plant ... Key words: Camellia sinensis, leaf albinism, light intensity, photosynthetic pigments, amino acids, chloroplast. .... tructive reaction or photodamage which occurs in the.

  18. Soome maiustustetootja Leaf saab peatselt uue omaniku / Tõnis Arnover

    Index Scriptorium Estoniae

    Arnover, Tõnis, 1952-

    2004-01-01

    Hollandi kontsern CSM otsustas loobuda maiustusetootmisest, sh. Soome magusatootjast Leaf ning keskenduda pagaritööstustoorme, biokemikaalide ning suhkrutoodete valmistamisele. Diagramm: CSMi kasumlikkus vähenes. Vt. samas: Eestis menukad kurgupastillid

  19. Leaf water oxygen isotope measurement by direct equilibration

    National Research Council Canada - National Science Library

    Song, Xin; Barbour, Margaret M

    2016-01-01

    The oxygen isotope composition of leaf water imparts a signal to a range of molecules in the atmosphere and biosphere, but has been notoriously difficult to measure in studies requiring a large number...

  20. Effect of Ethanolic Leaf Extract of Senna Fistula on some ...

    African Journals Online (AJOL)

    olayemitoyin

    Haematological Parameters, Lipid Profile and Oxidative Stress ... and decreases the production of free radicals associated with diabetes. Keywords: .... of repeated oral administration of ethanolic leaf extract of Senna .... Statistical Analysis.