WorldWideScience

Sample records for underlying plant response

  1. Exploring the Response of Plants Grown under Uranium Stress

    Energy Technology Data Exchange (ETDEWEB)

    Doustaly, Fany; Berthet, Serge; Bourguignon, Jacques [CEA, iRTSV, Laboratoire de Physiologie Cellulaire Vegetale, UMR 5168 CEA-CNRS-INRA-Univ. Grenoble Alpes (France); Combes, Florence; Vandenbrouck, Yves [CEA, iRTSV, Laboratoire de Biologie a Grande Echelle, EDyP, CEA-Grenoble (France); Carriere, Marie [CEA, INAC, LAN, UMR E3 CEA-Universite Joseph Fourier, Grenoble (France); Vavasseur, Alain [CEA, IBEB, LBDP, Saint Paul lez Durance, CEA Cadarache (France)

    2014-07-01

    Uranium is a natural element which is mainly redistributed in the environment due to human activity, including accidents and spillages. Plants may be useful in cleaning up after incidents, although little is yet known about the relationship between uranium speciation and plant response. We analyzed the impact of different uranium (U) treatments on three plant species namely sunflower, oilseed rape and wheat. Using inductively coupled plasma mass spectrometry elemental analysis, together with a panel of imaging techniques including scanning electron microscopy coupled with energy dispersive spectroscopy, transmission electron microscopy and particle-induced X-ray emission spectroscopy, we have recently shown how chemical speciation greatly influences the accumulation and distribution of U in plants. Uranyl (UO{sub 2}{sup 2+} free ion) is the predominant mobile form in soil surface at low pH in absence of ligands. With the aim to characterize the early plant response to U exposure, complete Arabidopsis transcriptome microarray experiments were conducted on plants exposed to 50 μM uranyl nitrate for 2, 6 and 30 h and highlighted a set of 111 genes with modified expression at these three time points. Quantitative real-time RT-PCR experiments confirmed and completed CATMA micro-arrays results allowing the characterization of biological processes perturbed by U. Functional categorization of deregulated genes emphasizes oxidative stress, cell wall biosynthesis and hormone biosynthesis and signaling. We showed that U stress is perceived by plant cells like a phosphate starvation stress since several phosphate deprivation marker genes were deregulated by U and also highlighted perturbation of iron homeostasis by U. Hypotheses are presented to explain how U perturbs the iron uptake and signaling response. These results give preliminary insights into the pathways affected by uranyl uptake, which will be of interest for engineering plants to help clean areas contaminated with

  2. Analyses of transient plant response under emergency situations

    Energy Technology Data Exchange (ETDEWEB)

    Koyama, Kazuya [Advanced Reactor Technology, Co. Ltd., Engineering Department, Tokyo (Japan); Shimakawa, Yoshio; Hishida, Masahiko [Mitsubishi Heavy Industry, Ltd., Reactor Core Engineering and Safety Engineering Department, Tokyo (Japan)

    1999-03-01

    In order to support development of the dynamic reliability analysis program DYANA, analyses were made on the event sequences anticipated under emergency situations using the plant dynamics simulation computer code Super-COPD. The analytical models were developed for Super-COPD such as the guard vessel, the maintenance cooling system, the sodium overflow and makeup system, etc. in order to apply the code to the simulation of the emergency situations. The input data were prepared for the analyses. About 70 sequences were analyzed, which are categorized into the following events: (1) PLOHS (Protected Loss of Heat Sink), (2) LORL (Loss of Reactor Level)-J: failure of sodium makeup by the primary sodium overflow and makeup system, (3) LORL-G : failure of primary coolant pump trip, (4) LORL-I: failure of the argon cover gas isolation, and (5) heat removal only using the ventilation system of the primary cooling system rooms. The results were integrated into an input file for preparing the functions for the neural network simulation. (author)

  3. Plant's adaptive response under UV-B-radiation influence

    International Nuclear Information System (INIS)

    Danil'chenko, O.A.; Grodzinskij, D.M.

    2002-01-01

    Reduction of ozone layer, owing to anthropogenic contamination of an atmosphere results in increase of intensity of UV-radiation and shift of its spectrum in the short-wave side that causes strengthening of various biological effects of irradiation. Consequences of these processes may include increase of injuring of plants and decrease of productivity of agricultural crops to increased UV levels. The important significance in the plant's adaptation to different unfavorable factors has the plant's radioadaptive answer. It has been shown that radioadaptation of plants occurred not only after irradiation with g-radiation in low doses but after UV-rays action . Reaction of radioadaptation it seems to be nonspecific phenomenon in relation to type radiations

  4. Plants under dual attack

    NARCIS (Netherlands)

    Ponzio, C.A.M.

    2016-01-01

    Though immobile, plants are members of complex environments, and are under constant threat from a wide range of attackers, which includes organisms such as insect herbivores or plant pathogens. Plants have developed sophisticated defenses against these attackers, and include chemical responses such

  5. Responses of two invasive plants under various microclimate conditions in the Seoul metropolitan region.

    Science.gov (United States)

    Song, Uhram; Mun, Saeromi; Ho, Chang-Hoi; Lee, Eun Ju

    2012-06-01

    The possible consequences of global warming on plant communities and ecosystems have wide-ranging ramifications. We examined how environmental change affects plant growth as a function of the variations in the microclimate along an urban-suburban climate gradient for two allergy-inducing, invasive plants, Humulus japonicus and Ambrosia artemisiifolia var. elatior. The environmental factors and plant growth responses were measured at two urban sites (Gangbuk and Seongbuk) and two suburban sites (Goyang and Incheon) around Seoul, South Korea. The mean temperatures and CO(2) concentrations differed significantly between the urban (14.8 °C and 439 ppm CO(2)) and suburban (13.0 °C and 427 ppm CO(2)) sites. The soil moisture and nitrogen contents of the suburban sites were higher than those at the urban sites, especially for the Goyang site. The two invasive plants showed significantly higher biomasses and nitrogen contents at the two urban sites. We conducted experiments in a greenhouse to confirm the responses of the plants to increased temperatures, and we found consistently higher growth rates under conditions of higher temperatures. Because we controlled the other factors, the better performance of the two invasive plants appears to be primarily attributable to their responses to temperature. Our study demonstrates that even small temperature changes in the environment can confer significant competitive advantages to invasive species. As habitats become urbanized and warmer, these invasive plants should be able to displace native species, which will adversely affect people living in these areas.

  6. PHYSIOLOGICAL RESPONSES OF DWARF COCONUT PLANTS UNDER WATER DEFICIT IN SALT - AFFECTED SOILS

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    ALEXANDRE REUBER ALMEIDA DA SILVA

    2017-01-01

    Full Text Available The objective of this study was to characterize the physiological acclimation responses of young plants of the dwarf coconut cultivar ̳Jiqui Green‘ associated with tolerance to conditions of multiple abiotic stresses (drought and soil salinity, acting either independently or in combination. The study was conducted under controlled conditions and evaluated the following parameters: leaf gas exchange, quantum yield of chlorophyll a fluorescence, and relative contents of total chlorophyll (SPAD index. The experiment was conducted under a randomized block experimental design, in a split plot arrangement. In the plots, plants were exposed to different levels of water stress, by imposing potential crop evapotranspiration replacement levels equivalent to 100%, 80%, 60%, 40%, and 20%, whereas in subplots, plants were exposed to different levels of soil salinity (1.72, 6.25, 25.80, and 40.70 dS m - 1 . Physiological mechanisms were effectively limited when water deficit and salinity acted separately and/or together. Compared with soil salinity, water stress was more effective in reducing the measured physiological parameters. The magnitudes of the responses of plants to water supply and salinity depended on the intensity of stress and evaluation period. The physiological acclimation responses of plants were mainly related to stomatal regulation. The coconut tree has a number of physiological adjustment mechanisms that give the species partial tolerance to drought stress and/or salt, thereby enabling it to revegetate salinated areas, provided that its water requirements are at least partially met.

  7. Relationship between Aflatoxin Contamination and Physiological Responses of Corn Plants under Drought and Heat Stress

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    Nacer Bellaloui

    2012-11-01

    Full Text Available Increased aflatoxin contamination in corn by the fungus Aspergillus flavus is associated with frequent periods of drought and heat stress during the reproductive stages of the plants. The objective of this study was to evaluate the relationship between aflatoxin contamination and physiological responses of corn plants under drought and heat stress. The study was conducted in Stoneville, MS, USA under irrigated and non-irrigated conditions. Five commercial hybrids, P31G70, P33F87, P32B34, P31B13 and DKC63-42 and two inbred germplasm lines, PI 639055 and PI 489361, were evaluated. The plants were inoculated with Aspergillus flavus (K-54 at mid-silk stage, and aflatoxin contamination was determined on the kernels at harvest. Several physiological measurements which are indicators of stress response were determined. The results suggested that PI 639055, PI 489361 and hybrid DKC63-42 were more sensitive to drought and high temperature stress in the non-irrigated plots and P31G70 was the most tolerant among all the genotypes. Aflatoxin contamination was the highest in DKC63-42 and PI 489361 but significantly lower in P31G70. However, PI 639055, which is an aflatoxin resistant germplasm, had the lowest aflatoxin contamination, even though it was one of the most stressed genotypes. Possible reasons for these differences are discussed. These results suggested that the physiological responses were associated with the level of aflatoxin contamination in all the genotypes, except PI 639055. These and other physiological responses related to stress may help examine differences among corn genotypes in aflatoxin contamination.

  8. Response of wheat plants to sodium and calcium ion interaction under saline environment

    International Nuclear Information System (INIS)

    Zaman, B.; Niazi, B.H.; Athar, M.; Ahmad, M.

    2005-01-01

    Wheat being a glycophyte crop, responds differently to saline-sodic soil environmental conditions. The application of calcium is multidimensional with respect to sodium ion and plant part response. This study was conducted to record the response of shoot and root to sodium and calcium interaction under saline environment. Wheat seed of variety Punjab 85 were raised in quartz sand. Later on the seedlings were transplanted to pots containing Hoagland's nutrient solution along with NaCl at 0 mM. and 50 mM. Calcium was applied as CaSO 4 2H O at 3m M. and 6 mM. Under saline conditions shoot showed positive response to sodium ion in the presence of higher calcium. Relative water contents were higher in the root system at 6 mM of CaSO 4 .2H 2 O under saline condition. Growth responses to potassium and Magnesium in the presence of sodium induced salinity with calcium ion interaction remained variable

  9. Cross Talk between H2O2 and Interacting Signal Molecules under Plant Stress Response

    Science.gov (United States)

    Saxena, Ina; Srikanth, Sandhya; Chen, Zhong

    2016-01-01

    It is well established that oxidative stress is an important cause of cellular damage. During stress conditions, plants have evolved regulatory mechanisms to adapt to various environmental stresses. One of the consequences of stress is an increase in the cellular concentration of reactive oxygen species, which is subsequently converted to H2O2. H2O2 is continuously produced as the byproduct of oxidative plant aerobic metabolism. Organelles with a high oxidizing metabolic activity or with an intense rate of electron flow, such as chloroplasts, mitochondria, or peroxisomes are major sources of H2O2 production. H2O2 acts as a versatile molecule because of its dual role in cells. Under normal conditions, H2O2 immerges as an important factor during many biological processes. It has been established that it acts as a secondary messenger in signal transduction networks. In this review, we discuss potential roles of H2O2 and other signaling molecules during various stress responses. PMID:27200043

  10. Simulating Crop Evapotranspiration Response under Different Planting Scenarios by Modified SWAT Model in an Irrigation District, Northwest China.

    Directory of Open Access Journals (Sweden)

    Xin Liu

    Full Text Available Modelling crop evapotranspiration (ET response to different planting scenarios in an irrigation district plays a significant role in optimizing crop planting patterns, resolving agricultural water scarcity and facilitating the sustainable use of water resources. In this study, the SWAT model was improved by transforming the evapotranspiration module. Then, the improved model was applied in Qingyuan Irrigation District of northwest China as a case study. Land use, soil, meteorology, irrigation scheduling and crop coefficient were considered as input data, and the irrigation district was divided into subdivisions based on the DEM and local canal systems. On the basis of model calibration and verification, the improved model showed better simulation efficiency than did the original model. Therefore, the improved model was used to simulate the crop evapotranspiration response under different planting scenarios in the irrigation district. Results indicated that crop evapotranspiration decreased by 2.94% and 6.01% under the scenarios of reducing the planting proportion of spring wheat (scenario 1 and summer maize (scenario 2 by keeping the total cultivated area unchanged. However, the total net output values presented an opposite trend under different scenarios. The values decreased by 3.28% under scenario 1, while it increased by 7.79% under scenario 2, compared with the current situation. This study presents a novel method to estimate crop evapotranspiration response under different planting scenarios using the SWAT model, and makes recommendations for strategic agricultural water management planning for the rational utilization of water resources and development of local economy by studying the impact of planting scenario changes on crop evapotranspiration and output values in the irrigation district of northwest China.

  11. Simulating Crop Evapotranspiration Response under Different Planting Scenarios by Modified SWAT Model in an Irrigation District, Northwest China.

    Science.gov (United States)

    Liu, Xin; Wang, Sufen; Xue, Han; Singh, Vijay P

    2015-01-01

    Modelling crop evapotranspiration (ET) response to different planting scenarios in an irrigation district plays a significant role in optimizing crop planting patterns, resolving agricultural water scarcity and facilitating the sustainable use of water resources. In this study, the SWAT model was improved by transforming the evapotranspiration module. Then, the improved model was applied in Qingyuan Irrigation District of northwest China as a case study. Land use, soil, meteorology, irrigation scheduling and crop coefficient were considered as input data, and the irrigation district was divided into subdivisions based on the DEM and local canal systems. On the basis of model calibration and verification, the improved model showed better simulation efficiency than did the original model. Therefore, the improved model was used to simulate the crop evapotranspiration response under different planting scenarios in the irrigation district. Results indicated that crop evapotranspiration decreased by 2.94% and 6.01% under the scenarios of reducing the planting proportion of spring wheat (scenario 1) and summer maize (scenario 2) by keeping the total cultivated area unchanged. However, the total net output values presented an opposite trend under different scenarios. The values decreased by 3.28% under scenario 1, while it increased by 7.79% under scenario 2, compared with the current situation. This study presents a novel method to estimate crop evapotranspiration response under different planting scenarios using the SWAT model, and makes recommendations for strategic agricultural water management planning for the rational utilization of water resources and development of local economy by studying the impact of planting scenario changes on crop evapotranspiration and output values in the irrigation district of northwest China.

  12. Perspectives on deciphering mechanisms underlying plant heat stress response and thermotolerance

    Directory of Open Access Journals (Sweden)

    Kamila Lucia Bokszczanin

    2013-08-01

    Full Text Available Global warming is a major threat for agriculture and food safety and in many cases the negative effects are already apparent. The current challenge of basic and applied plant science is to decipher the molecular mechanisms of heat stress response and thermotolerance in detail and use this information to identify genotypes that will withstand unfavorable environmental conditions. Nowadays X-omics approaches complement the findings of previous targeted studies and highlight the complexity of heat stress response mechanisms giving information for so far unrecognized genes, proteins and metabolites as potential key players of thermotolerance. Even more, roles of epigenetic mechanisms and the involvement of small RNAs in thermotolerance are currently emerging and thus open new directions of yet unexplored areas of plant heat stress response. In parallel it is emerging that although the whole plant is vulnerable to heat, specific organs are particularly sensitive to elevated temperatures. This has redirected research from the vegetative to generative tissues. The sexual reproduction phase is considered as the most sensitive to heat and specifically pollen exhibits the highest sensitivity and frequently an elevation of the temperature just a few degrees above the optimum during pollen development can have detrimental effects for crop production. Compared to our knowledge on heat stress response of vegetative tissues, the information on pollen is still scarce. Nowadays, several techniques for high-throughput X-omics approaches provide major tools to explore the principles of pollen heat stress response and thermotolerance mechanisms in specific genotypes. The collection of such information will provide an excellent support for improvement of breeding programs to facilitate the development of tolerant cultivars. The review aims at describing the current knowledge of thermotolerance mechanisms and the technical advances which will foster new insights into

  13. Fungal Communities in Rhizosphere Soil under Conservation Tillage Shift in Response to Plant Growth

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    Ziting Wang

    2017-07-01

    Full Text Available Conservation tillage is an extensively used agricultural practice in northern China that alters soil texture and nutrient conditions, causing changes in the soil microbial community. However, how conservation tillage affects rhizosphere and bulk soil fungal communities during plant growth remains unclear. The present study investigated the effect of long-term (6 years conservation (chisel plow, zero and conventional (plow tillage during wheat growth on the rhizosphere fungal community, using high-throughput sequencing of the internal transcribed spacer (ITS gene and quantitative PCR. During tillering, fungal alpha diversity in both rhizosphere and bulk soil were significantly higher under zero tillage compared to other methods. Although tillage had no significant effect during the flowering stage, fungal alpha diversity at this stage was significantly different between rhizosphere and bulk soils, with bulk soil presenting the highest diversity. This was also reflected in the phylogenetic structure of the communities, as rhizosphere soil communities underwent a greater shift from tillering to flowering compared to bulk soil communities. In general, less variation in community structure was observed under zero tillage compared to plow and chisel plow treatments. Changes in the relative abundance of the fungal orders Capnodiales, Pleosporales, and Xylariales contributed the highest to the dissimilarities observed. Structural equation models revealed that the soil fungal communities under the three tillage regimes were likely influenced by the changes in soil properties associated with plant growth. This study suggested that: (1 differences in nutrient resources between rhizosphere and bulk soils can select for different types of fungi thereby increasing community variation during plant growth; (2 tillage can alter fungal communities' variability, with zero tillage promoting more stable communities. This work suggests that long-term changes in

  14. Woody-plant ecosystems under climate change and air pollution-response consistencies across zonobiomes?

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    Matyssek, R; Kozovits, A R; Wieser, G; King, J; Rennenberg, H

    2017-06-01

    Forests store the largest terrestrial pools of carbon (C), helping to stabilize the global climate system, yet are threatened by climate change (CC) and associated air pollution (AP, highlighting ozone (O3) and nitrogen oxides (NOx)). We adopt the perspective that CC-AP drivers and physiological impacts are universal, resulting in consistent stress responses of forest ecosystems across zonobiomes. Evidence supporting this viewpoint is presented from the literature on ecosystem gross/net primary productivity and water cycling. Responses to CC-AP are compared across evergreen/deciduous foliage types, discussing implications of nutrition and resource turnover at tree and ecosystem scales. The availability of data is extremely uneven across zonobiomes, yet unifying patterns of ecosystem response are discernable. Ecosystem warming results in trade-offs between respiration and biomass production, affecting high elevation forests more than in the lowland tropics and low-elevation temperate zone. Resilience to drought is modulated by tree size and species richness. Elevated O3 tends to counteract stimulation by elevated carbon dioxide (CO2). Biotic stress and genomic structure ultimately determine ecosystem responsiveness. Aggrading early- rather than mature late-successional communities respond to CO2 enhancement, whereas O3 affects North American and Eurasian tree species consistently under free-air fumigation. Insect herbivory is exacerbated by CC-AP in biome-specific ways. Rhizosphere responses reflect similar stand-level nutritional dynamics across zonobiomes, but are modulated by differences in tree-soil nutrient cycling between deciduous and evergreen systems, and natural versus anthropogenic nitrogen (N) oversupply. The hypothesis of consistency of forest responses to interacting CC-AP is supported by currently available data, establishing the precedent for a global network of long-term coordinated research sites across zonobiomes to simultaneously advance both

  15. Antioxidant System Response and cDNA-SCoT Marker Profiling in Phoenix dactylifera L. Plant under Salinity Stress

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    Fahad Al-Qurainy

    2017-01-01

    Full Text Available Many Phoenix dactylifera (date palm cultivars are grown in the arid and semiarid regions of the world, including Saudi Arabia. P. dactylifera is highly tolerant to salinity stress. To investigate the response of Khalas cultivar of P. dactylifera, two-month-old plants were treated with sodium chloride (50, 100, and 150 mM NaCl for three months. Our result showed that proline content was higher in all treated plants compared to control plants. Thiobarbituric acid reactive substances (TBARS were increased at 100 and 150 mM NaCl treatments; however, the result was found nonsignificant between control and plants treated at 50 mM NaCl. Similarly, enzyme activities of catalase (CAT and superoxide dismutase (SOD were 0.805 and 0.722 U/mg protein/min, respectively, and were greater at 100 and 150 mM NaCl treatments compared to the control plants. Total chlorophyll content and fresh weight of shoots and roots decreased substantially with the increase of salinity. A cDNA start codon-targeted (cDNA-SCoT marker showed a variation in different gene expressions profiling between treated and untreated plants under various NaCl concentrations.

  16. Antioxidant System Response and cDNA-SCoT Marker Profiling in Phoenix dactylifera L. Plant under Salinity Stress

    Science.gov (United States)

    Al-Qurainy, Fahad

    2017-01-01

    Many Phoenix dactylifera (date palm) cultivars are grown in the arid and semiarid regions of the world, including Saudi Arabia. P. dactylifera is highly tolerant to salinity stress. To investigate the response of Khalas cultivar of P. dactylifera, two-month-old plants were treated with sodium chloride (50, 100, and 150 mM NaCl) for three months. Our result showed that proline content was higher in all treated plants compared to control plants. Thiobarbituric acid reactive substances (TBARS) were increased at 100 and 150 mM NaCl treatments; however, the result was found nonsignificant between control and plants treated at 50 mM NaCl. Similarly, enzyme activities of catalase (CAT) and superoxide dismutase (SOD) were 0.805 and 0.722 U/mg protein/min, respectively, and were greater at 100 and 150 mM NaCl treatments compared to the control plants. Total chlorophyll content and fresh weight of shoots and roots decreased substantially with the increase of salinity. A cDNA start codon-targeted (cDNA-SCoT) marker showed a variation in different gene expressions profiling between treated and untreated plants under various NaCl concentrations. PMID:28702461

  17. Analysis of molecular responses in plants under the conditions of excess-aluminium stress

    Energy Technology Data Exchange (ETDEWEB)

    Masaoka, Yoshikuni; Arakawa, Yusuke; Asanuma, Shuichi [Kyushu National Agricultural Experiment Station, Kumamoto (Japan)] [and others

    1999-02-01

    Recent soil environments in Kyushu and Okinawa regions have a possibility to impair agricultural products because elution of aluminum (Al) from the soil has been progressing because of its elution by soil acidification. In this study, {sup 26}Al-tracing method using tandem accelerator mass spectroscopy was applied to investigate the effects of aluminum in the soil on a few plants. The results showed that Al accumulation in mitochondria was several times of higher in Dayton, a Al-resistant strain of barley than kearney, a sensitive one. It was thus suggested that mitochondria, which has been known to participates in respiration and cell death (apoptosis), has also an important role in the physiological functions of Al. The growth of barley on the soil of pH 5.0 was significantly inhibited with Al and such growth inhibition was also observed in barley grown in hydroponics, especially, the growth of kearney was markedly inhibited. When the effects of 1 mM Al were compared between Dayton and kearney strains, there were large differences in the growth of their leaves. Then, the correlative resistance to Al and barley leaf stripe mosaic virus (BSMV) was examined in these two barley strains. The virus concentration in kearney leaves 30 days after an inoculation of BSMV was similar to that in Dayton ones. Under stress conditions with a low level Al, both strains infected with BSMW developed necrotic damages, whereas under the stress condition at a high level Al (100 {mu}M), they developed severe necrosis even without inoculation with BSMW. As an increase of the amount of absorbed Al, the phosphate concentration in the cell was decreased and the decrease was marked in the resistant strain, Dayton. (M.N.)

  18. Identification of drought-responsive miRNAs and physiological characterization of tea plant (Camellia sinensis L.) under drought stress.

    Science.gov (United States)

    Guo, Yuqiong; Zhao, Shanshan; Zhu, Chen; Chang, Xiaojun; Yue, Chuan; Wang, Zhong; Lin, Yuling; Lai, Zhongxiong

    2017-11-21

    Drought stress is one of the major natural challenges in the main tea-producing regions of China. The tea plant (Camellia sinensis) is a traditional beverage plant whose growth status directly affects tea quality. Recent studies have revealed that microRNAs (miRNAs) play key functions in plant growth and development. Although some miRNAs have been identified in C. sinensis, little is known about their roles in the drought stress response of tea plants. Physiological characterization of Camellia sinensis 'Tieguanyin' under drought stress showed that the malondialdehyde concentration and electrical conductivity of leaves of drought-stressed plants increased when the chlorophyll concentration decreased under severe drought stress. We sequenced four small-RNA (sRNA) libraries constructed from leaves of plants subjected to four different treatments, normal water supply (CK); mild drought stress (T1); moderate drought stress (T2) and severe drought stress (T3). A total of 299 known mature miRNA sequences and 46 novel miRNAs were identified. Gene Ontology enrichment analysis revealed that most of the differentially expressed-miRNA target genes were related to regulation of transcription. Kyoto Encyclopedia of Genes and Genomes analysis revealed that the most highly enriched pathways under drought stress were D-alanine metabolism, sulfur metabolism, and mineral absorption pathways. Real-time quantitative PCR (qPCR) was used to validate the expression patterns of 21 miRNAs (2 up-regulated and 19 down-regulated under drought stress). The observed co-regulation of the miR166 family and their targets ATHB-14-like and ATHB-15-like indicate the presence of negative feedback regulation in miRNA pathways. Analyses of drought-responsive miRNAs in tea plants showed that most of differentially expressed-miRNA target genes were related to regulation of transcription. The results of study revealed that the expressions of phase-specific miRNAs vary with morphological, physiological, and

  19. Possible mechanisms underlying abundance and diversity responses of nematode communities to plant diversity

    NARCIS (Netherlands)

    Cortois, R.; Veen, G.F.; Duyts, H.; Abbas, M.; Strecker, T; Kostenko, O.; Eisenhauer, Nico; Scheu, S.; Gleixner, G.; De Deyn, G.B.; van der Putten, W.H.

    2017-01-01

    Plant diversity is known to influence the abundance and diversity of belowground biota; however, patterns are not well predictable and there is still much unknown about the driving mechanisms. We analyzed changes in soil nematode community composition as affected by long-term manipulations of plant

  20. Possible mechanisms underlying abundance and diversity responses of nematode communities to plant diversity

    NARCIS (Netherlands)

    Cortois, R.; Veen, G.F.; Duyts, Henk; Abbas, Maike; Strecker, Tanja; Kostenko, Olga; Eisenhauer, Nico; Scheu, Stefan; Gleixner, Gerd; Deyn, De Gerlinde B.; Putten, van der Wim H.

    2017-01-01

    Plant diversity is known to influence the abundance and diversity of belowground biota; however, patterns are not well predictable and there is still much unknown about the driving mechanisms. We analyzed changes in soil nematode community composition as affected by long-term manipulations of

  1. Foliar Reflectance and Fluorescence Responses for Plants Under Nitrogen Stress Determined with Active and Passive Systems

    Science.gov (United States)

    Middleton, E. M.; McMurtrey, J. E.; Campbell, P. K. Entcheva; Corp, L. A.; Butcher, L. M.; Chappelle, E. W.

    2003-01-01

    Vegetation productivity is driven by nitrogen (N) availability in soils. Both excessive and low soil N induce physiological changes in plant foliage. In 2001, we examined the use of spectral fluorescence and reflectance measurements to discriminate among plants provided different N fertilizer application rates: 20%, 50%, 100% and 150% of optimal N levels. A suite of optical, fluorescence, and biophysical measurements were collected on leaves from field grown corn (Zea mays L.) and soybean plants (Glycine max L.) grown in pots (greenhouse + ambient sunlight daily). Three types of steady state laser-induced fluorescence measurements were made on adaxial and abaxial surfaces: 1) fluorescence images in four 10 nm bands (blue, green, red, far-red) resulting from broad irradiance excitation; 2) emission spectra (5 nm resolution) produced by excitation at single wavelengths (280,380 or 360, and 532 nm); and 3) excitation spectra (2 nm resolution), with emission wavelengths fixed at wavelengths centered on selected solar Fraunhofer lines (532,607,677 and 745 nm). Two complementary sets of high resolution (less than 2 nm) optical spectra were acquired for both adaxial and abaxial leaf surfaces: 1) optical properties (350-2500 nm) for reflectance, transmittance, and absorptance; and 2) reflectance spectra (500-1000 nm) acquired with and without a short pass filter at 665 nm to determine the fluorescence contribution to apparent reflectance in the 650-750 spectrum, especially at the 685 and 740 nm chlorophyll fluorescence (ChIF) peaks. The strongest relationships between foliar chemistry and optical properties were demonstrated for C/N content and two optical parameters associated with the red edge inflection point. Select optical properties and ChIF parameters were highly correlated for both species. A significant contribution of ChIF to apparent reflectance was observed, averaging 10-25% at 685 nm and 2 - 6% at 740 nm over all N treatments. Discrimination of N treatment

  2. Foliar Reflectance and Fluorescence Responses for Corn and Soybean Plants Under Nitrogen Stress

    Science.gov (United States)

    Middleton, E. M.; Campbell, P. K. Entcheva; Corp, L. A.; Butcher, L. M.; McMurtrey, J. E.

    2003-01-01

    We are investigating the use of spectral indices derived from actively induced fluorescence spectra and passive optical spectra. We examined the influence of photosynthetic pigment, carbon (C) and nitrogen (N) content on the spectral fluorescence and passive optical property characteristics of mature, upper leaves from plants provided different N fertilizer application rates: 20%, 50%, 100% and 150% of recommended N levels. A suite of optical, fluorescence, and biophysical measurements were collected on leaves from field grown corn (Zea mays L.) and soybean plants (Glycine max L.) grown in pots (greenhouse + ambient sunlight. Steady state laser-induced fluorescence emission spectra (5 nm resolution) were obtained from adaxial and abaxial surfaces resulting from excitation at single wavelengths (280, 380 or 360, and 532 nm). For emission spectra produced by each of these excitation wavelengths, ratios of emission peaks were calculated, including the red far-red chlorophyll fluorescence (ChlF) ratio (F685/F740) and the far-red/green (F740/F525) ratio. High resolution (treatment groups was possible with specific fluorescence band ratios (e.g., F740/F525 obtained with 380 nm excitation). Higher ChlF and blue-green emissions were measured from the abaxial leaf surfaces. Abaxial surfaces also produced higher reflectances, in general, in the 400-800 nm spectrum.

  3. Foliar Reflectance and Fluorescence Responses for Corn and Soybean Plants Under Nitrogen Stress

    Science.gov (United States)

    Middleton, E. M.; Campbell, P. K. Entcheva; Corp, L. A.; Butcher, L. M.; McMurtrey, J. E.

    2003-01-01

    We are investigating the use of spectral indices derived from actively induced fluorescence spectra and passive optical spectra. We examined the influence of photosynthetic pigment, carbon (C) and nitrogen (N) content on the spectral fluorescence and passive optical property characteristics of mature, upper leaves from plants provided different N fertilizer application rates: 20%, 50%, 100% and 150% of recommended N levels. A suite of optical, fluorescence, and biophysical measurements were collected on leaves from field grown corn (Zea mays L.) and soybean plants (Glycine max L.) grown in pots (greenhouse + ambient sunlight. Steady state laser-induced fluorescence emission spectra (5 nm resolution) were obtained from adaxial and abaxial surfaces resulting from excitation at single wavelengths (280, 380 or 360, and 532 nm). For emission spectra produced by each of these excitation wavelengths, ratios of emission peaks were calculated, including the red far-red chlorophyll fluorescence (ChlF) ratio (F685/F740) and the far-red/green (F740/F525) ratio. High resolution (< 3 nm) optical spectra (350-2500 nm) of reflectance, transmittance, and absorptance were also acquired for both adaxial and abaxial leaf surfaces. Species differences were demonstrated for several optical parameters. A 'red edge' derivative ratio determined from transmittance spectra [as the maximum first deivative, between 650-750 nm, normalized to the value at 744 nm, or Dmax/D744], was strongly associated with the C/N ratio (r(exp 2) = 0.90, P +/- 0.001). This ratio, calculated from reflectance spectra, was inversely related to chlorophyll b content (r(exp 2) = 0.91, P +/- 0.001) as was the ChlF (F685/F740) ratio obtained with 532 nm excitation (r(exp 2) = 0.76, P +/- 0.01). Discrimination of N treatment groups was possible with specific fluorescence band ratios (e.g., F740/F525 obtained with 380 nm excitation). Higher ChlF and blue-green emissions were measured from the abaxial leaf surfaces

  4. Molecular phenology in plants: in natura systems biology for the comprehensive understanding of seasonal responses under natural environments.

    Science.gov (United States)

    Kudoh, Hiroshi

    2016-04-01

    Phenology refers to the study of seasonal schedules of organisms. Molecular phenology is defined here as the study of the seasonal patterns of organisms captured by molecular biology techniques. The history of molecular phenology is reviewed briefly in relation to advances in the quantification technology of gene expression. High-resolution molecular phenology (HMP) data have enabled us to study phenology with an approach of in natura systems biology. I review recent analyses of FLOWERING LOCUS C (FLC), a temperature-responsive repressor of flowering, along the six steps in the typical flow of in natura systems biology. The extensive studies of the regulation of FLC have made this example a successful case in which a comprehensive understanding of gene functions has been progressing. The FLC-mediated long-term memory of past temperatures creates time lags with other seasonal signals, such as photoperiod and short-term temperature. Major signals that control flowering time have a phase lag between them under natural conditions, and hypothetical phase lag calendars are proposed as mechanisms of season detection in plants. Transcriptomic HMP brings a novel strategy to the study of molecular phenology, because it provides a comprehensive representation of plant functions. I discuss future perspectives of molecular phenology from the standpoints of molecular biology, evolutionary biology and ecology. © 2015 The Author. New Phytologist © 2015 New Phytologist Trust.

  5. The responsibilities of the in-plant environmental protection officer under civil law and under criminal law. Zivilrechtliche und strafrechtliche Verantwortung des Betriebsbeauftragten fuer Umweltschutz

    Energy Technology Data Exchange (ETDEWEB)

    Salje, P.

    1993-11-20

    The scope of responsibilities of the in-plant environmental protection officer covers a wide range of tasks: Water protection, waste management, control of emissions for air pollution abatement, emergency preparedness, radiological protection. What are the consequences for the EP officer in case of neglect This is the topic of the contribution, discussed from the viewpoint of criminal law and private law. The criminal liability of the EP officer results from the EP officer committing an offence either by wilful act or by neglect, it, in the latter case, the officer is in a warranty position. Under private law, the EP officer is subject to third party liability within the framework defined by Paragraph 823 BGB. There is no possibility for him to claim restriction of liability refering to the enhanced risks involved in his job. Hence a sound professional indemnity insurance is recommendable. (orig.)

  6. Simulating Crop Evapotranspiration Response under Different Planting Scenarios by Modified SWAT Model in an Irrigation District, Northwest China

    OpenAIRE

    Liu, Xin; Wang, Sufen; Xue, Han; Singh, Vijay P.

    2015-01-01

    Modelling crop evapotranspiration (ET) response to different planting scenarios in an irrigation district plays a significant role in optimizing crop planting patterns, resolving agricultural water scarcity and facilitating the sustainable use of water resources. In this study, the SWAT model was improved by transforming the evapotranspiration module. Then, the improved model was applied in Qingyuan Irrigation District of northwest China as a case study. Land use, soil, meteorology, irrigatio...

  7. Genotypic response of detached leaves versus intact plants for chlorophyll fluorescence parameters under high temperature stress in wheat

    DEFF Research Database (Denmark)

    Sharma, Dew Kumari; Fernández, Juan Olivares; Rosenqvist, Eva

    2014-01-01

    The genotypic response of wheat cultivars as affected by two methods of heat stress treatment (treatment of intact plants in growth chambers versus treatment of detached leaves in test tubes) in a temperature controlled water bath were compared to investigate how such different methods of heat....... The responses of the same cultivars to heat stress were compared between the two methods of heat treatment. The results showed that in detached leaves, all of the fluorescence parameters remained almost unaffected in control (20°C at all durations tested), indicating that the detachment itself did not affect...... variation that can be ascribed to the genetic differences among cultivars for a trait was estimated as genetic determination. During heat treatment, the genetic determination of most of the fluorescence parameters was lower in detached leaves than in intact plants. In addition, the correlation...

  8. Responses of soil N-fixing bacteria communities to invasive plant species under different types of simulated acid deposition

    Science.gov (United States)

    Wang, Congyan; Zhou, Jiawei; Jiang, Kun; Liu, Jun; Du, Daolin

    2017-06-01

    Biological invasions have incurred serious threats to native ecosystems in China, and soil N-fixing bacteria communities (SNB) may play a vital role in the successful plant invasion. Meanwhile, anthropogenic acid deposition is increasing in China, which may modify or upgrade the effects that invasive plant species can cause on SNB. We analyzed the structure and diversity of SNB by means of new generation sequencing technology in soils with different simulated acid deposition (SAD), i.e., different SO4 2- to NO3 - ratios, and where the invasive ( Amaranthus retroflexus L.) and the native species ( Amaranthus tricolor L.) grew mixed or isolated for 3 months. A. retroflexus itself did not exert significant effects on the diversity and richness of SNB but did it under certain SO4 2- to NO3 - ratios. Compared to soils where the native species grew isolated, the soils where the invasive A. retroflexus grew isolated showed lower relative abundance of some SNB classes under certain SAD treatments. Some types of SAD can alter soil nutrient content which in turn could affect SNB diversity and abundance. Specifically, greater SO4 2- to NO3 - ratios tended to have more toxic effects on SNB likely due to the higher exchange capacity of hydroxyl groups (OH-) between SO4 2- and NO3 -. As a conclusion, it can be expected a change in the structure of SNB after A. retroflexus invasion under acid deposition rich in sulfuric acid. This change may create a plant soil feedback favoring future A. retroflexus invasions.

  9. Responses of soil N-fixing bacteria communities to invasive plant species under different types of simulated acid deposition.

    Science.gov (United States)

    Wang, Congyan; Zhou, Jiawei; Jiang, Kun; Liu, Jun; Du, Daolin

    2017-06-01

    Biological invasions have incurred serious threats to native ecosystems in China, and soil N-fixing bacteria communities (SNB) may play a vital role in the successful plant invasion. Meanwhile, anthropogenic acid deposition is increasing in China, which may modify or upgrade the effects that invasive plant species can cause on SNB. We analyzed the structure and diversity of SNB by means of new generation sequencing technology in soils with different simulated acid deposition (SAD), i.e., different SO 4 2- to NO 3 - ratios, and where the invasive (Amaranthus retroflexus L.) and the native species (Amaranthus tricolor L.) grew mixed or isolated for 3 months. A. retroflexus itself did not exert significant effects on the diversity and richness of SNB but did it under certain SO 4 2- to NO 3 - ratios. Compared to soils where the native species grew isolated, the soils where the invasive A. retroflexus grew isolated showed lower relative abundance of some SNB classes under certain SAD treatments. Some types of SAD can alter soil nutrient content which in turn could affect SNB diversity and abundance. Specifically, greater SO 4 2- to NO 3 - ratios tended to have more toxic effects on SNB likely due to the higher exchange capacity of hydroxyl groups (OH - ) between SO 4 2- and NO 3 - . As a conclusion, it can be expected a change in the structure of SNB after A. retroflexus invasion under acid deposition rich in sulfuric acid. This change may create a plant soil feedback favoring future A. retroflexus invasions.

  10. Responses of spruce seedlings (Picea abies) to exhaust gas under laboratory conditions. 1. plant-insect interactions

    Energy Technology Data Exchange (ETDEWEB)

    Viskari, E.-L.; Koessi, S. [Kuopio Univ. (Finland). Dept. of Ecology and Environmental Science; Surakka, J.; Pasanen, P.; Ruuskanen, J. [Kuopio Univ. (Finland). Dept. of Environmental Sciences; Mirme, A. [Tartu Univ. (Estonia). Int. of Environmental Physics; Holopainen, J.K. [Kuopio Univ. (Finland). Dept. of Ecology and Environmental Science; Agricultural Research Centre, Plant Production research, Jokioinen (Finland)

    2000-07-01

    The effects of motor vehicle exhaust gas on Norway spruce seedlings (Picea abies (L) Karst) and plant-insect interaction of spruce shoot aphid (Cinara pilicornis Hartig) was studied. The exhaust gas concentrations in the fumigation chambers were monitored and controlled by measuring the concentration of nitrogen oxides (NO{sub x}) with a computer aided feedback system. The concentrations of major exhaust gas components (black carbon (BC), fine particles, VOCs and carbonyl compounds) in the chamber air were also measured. Responses of Norway spruce seedlings to a 2 and 3 week exhaust gas exposure and subsequent performance of spruce shoot aphid were studied using realistic exposure regimes; 50, 100 and 200 ppb NO{sub x}. The feedback control system based on NO{sub x} concentrations proved an adequate and practical means for controlling the concentration of exhaust gases and studying plant responses in controlled environment chambers. The exhaust exposure resulted in increased concentrations of proline, glutamine, threonine, aspartic acid, glycine and phenylalanine and decreased concentration of arginine, serine, alanine and glycine in young needles. No changes in soluble N concentrations were observed. The results are interpreted as a stress response rather than use of NO{sub x} as a nitrogen source. No changes in total phenolics and only transient changes in some individual terpene concentrations were detected. The exhaust gas exposure stressed the exposed seedlings, but had no significant effect on N metabolism or the production of defence chemicals. Aphid performance was not significantly affected. Soluble N, secondary metabolism and aphid performance were not sensitive to exhaust gas exposure during shoot elongation in Norway spruce. (author)

  11. Plant respiration under low oxygen

    Directory of Open Access Journals (Sweden)

    Guillermo Toro

    2015-08-01

    Full Text Available Respiration is an oxidative process controlled by three pathways: glycolysis, the tricarboxylic acid (TCA cycle, and oxidative phosphorylation (OXPHOS. Respiratory metabolism is ubiquitous in all organisms, but with differences among each other. For example in plants, because their high plasticity, respiration involves metabolic pathways with unique characteristics. In this way, in order to avoid states of low energy availability, plants exhibit great flexibility to bypass conventional steps of glycolysis, TCA cycle, and OXPHOS. To understand the energetic link between these alternative pathways, it is important to know the growth, maintenance, and ion uptake components of the respiration in plants. Changes in these components have been reported when plants are subjected to stress, such as oxygen deficiency. This review analyzes the current knowledge on the metabolic and functional aspects of plant respiration, its components and its response to environmental changes.

  12. The response of maize (Zea mays L.) plant assisted with bacterial consortium and fertilizer under oily sludge.

    Science.gov (United States)

    Shahzad, Asim; Saddiqui, Samina; Bano, Asghari

    2016-01-01

    The objective of this study was to evaluate the role of PGPR consortium and fertilizer alone and in combination on the physiology of maize grown under oily sludge stress environment as well on the soil nutrient status. Consortium was prepared from Bacillus cereus (Acc KR232400), Bacillus altitudinis (Acc KF859970), Comamonas (Delftia) belonging to family Comamonadacea (Acc KF859971) and Stenotrophomonasmaltophilia (Acc KF859973). The experiment was conducted in pots with complete randomized design with four replicates and kept in field. Oily sludge was mixed in ml and Ammonium nitrate and Diammonium phosphate (DAP) were added at 70 ug/g and 7 ug/g at sowing. The plant was harvested at 21 d for estimation of protein, proline and antioxidant enzymes superoxide dismutase (SOD) and peroxidase (POD). To study the degradation, total petroleum hydrocarbon was extracted by soxhelt extraction and extract was analyzed by GC-FID at different period after incubation. Combined application of consortium and fertilizer enhanced the germination %, protein and, proline content by 90,130 and 99% higher than untreated maize plants. Bioavailability of macro and micro nutrient was also enhanced with consortium and fertilizer in oily sludge. The consortium and fertilizer in combined treatment decreased the superoxide dismutase (SOD), peroxidase dismutase (POD) of the maize leaves grown in oily sludge. Degradation of total petroleum hydrocarbon (TPHs) was 59% higher in combined application of consortium and fertilizer than untreated maize at 3 d. The bacterial consortium can enhanced the maize tolerance to oily sludge and enhanced degradation of total petroleum hydrocarbon (TPHs). The maize can be considered as tolerant plant species to remediate oily sludge contaminated soils.

  13. Antioxidant System Response and cDNA-SCoT Marker Profiling inPhoenix dactyliferaL. Plant under Salinity Stress.

    Science.gov (United States)

    Al-Qurainy, Fahad; Khan, Salim; Nadeem, Mohammad; Tarroum, Mohamed; Gaafar, Abdel-Rhman Z

    2017-01-01

    Many Phoenix dactylifera (date palm) cultivars are grown in the arid and semiarid regions of the world, including Saudi Arabia. P. dactylifera is highly tolerant to salinity stress. To investigate the response of Khalas cultivar of P. dactylifera , two-month-old plants were treated with sodium chloride (50, 100, and 150 mM NaCl) for three months. Our result showed that proline content was higher in all treated plants compared to control plants. Thiobarbituric acid reactive substances (TBARS) were increased at 100 and 150 mM NaCl treatments; however, the result was found nonsignificant between control and plants treated at 50 mM NaCl. Similarly, enzyme activities of catalase (CAT) and superoxide dismutase (SOD) were 0.805 and 0.722 U/mg protein/min, respectively, and were greater at 100 and 150 mM NaCl treatments compared to the control plants. Total chlorophyll content and fresh weight of shoots and roots decreased substantially with the increase of salinity. A cDNA start codon-targeted (cDNA-SCoT) marker showed a variation in different gene expressions profiling between treated and untreated plants under various NaCl concentrations.

  14. Response of eight tropical plants to enhanced ammonia deposition under field, conditions prevalent with SO{sub 2} and NH{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Rao, M.V.; Khijneri, S.; Dubey, P.S.; Kumawat, D.M. [Vikram University, Ujjain (India). School of Studies in Botany

    1993-12-01

    The impact of SO{sub 2} on the deposition of ammonia and the response of eight tropical tree species to excess deposition of ammonia was investigated. This was achieved by studying physiological aspects like total sugars, protein, nitrate reductace (NR) activity, organic/inorganic nitrogen ratio, specific leaf area and foliar injury in plants growing under field conditions prevalent with SO{sub 2} and NH{sub 3}. Analysis of water soluble substances present on foliar surfaces of the trees indicated enhanced NH{sub 4}{sup +} deposition and thereby result in enhanced foliar protein contents. Though the enhanced nitrogen was almost the same in different plants, the plants exhibited differential metabolic disturbances. Critical analysis of the reults indicated three distinct types of plant response. Plants like {ital Azadirachta indica}, {ital Acacia auriculiformis} and {ital Bambusa arundinaceae} maintained enhanced total sugars and NR activity and incorporated excess NH{sub 4}{sup +} into proteins, thus enabling the plant to compensate/alleviate SO{sub 2} induced injury. Ficus benghalensis and Ficus religiosa maintained unaltered total sugars and NR activity and could partly incorporate NH{sub 4}{sup +} into proteins, thus modifying rhe SO{sub 2} impact to some extent. {ital Dalbergia sissoo}, {ital Eucalyptus rostrat}a and {ital Mangifera indica} could not incorporate the excess NH{sub 4}{sup +}, mainly due to declined total sugars. The results indicate the ability of a plant to undergo species specific metabolic changes in order to cope with the excess nitrogen deposition, which may ultimately result in increasing or decreasing tolerance to SO{sub 2}. 23 refs., 3 figs., 9 tabs.

  15. Differential response of radish plants to supplemental ultraviolet-B radiation under varying NPK levels: chlorophyll fluorescence, gas exchange and antioxidants.

    Science.gov (United States)

    Singh, Suruchi; Kumari, Rima; Agrawal, Madhoolika; Agrawal, Shashi Bhushan

    2012-07-01

    Current and projected increases in ultraviolet-B (UV-B; 280-315 nm) radiation may alter crop growth and yield by modifying the physiological and biochemical functions. This study was conducted to assess the possibility of alleviating the negative effects of supplemental UV-B (sUV-B; 7.2 kJ m⁻² day⁻¹; 280-315 nm) on radish (Raphanus sativus var Pusa Himani) by modifying soil nitrogen (N), phosphorus (P) and potassium (K) levels. The N, P and K treatments were recommended dose of N, P and K, 1.5 times recommended dose of N, P and K, 1.5 times recommended dose of N and 1.5 times recommended dose of K. Plants showed variations in their response to UV-B radiation under varying soil NPK levels. The minimum damaging effects of sUV-B on photosynthesis rate and stomatal conductance coupled with minimum reduction in chlorophyll content were recorded for plants grown at recommended dose of NPK. Flavonoids increased under sUV-B except in plants grown at 1.5 times recommended dose of N. Lipid peroxidation (LPO) also increased in response to sUV-B at all NPK levels with maximum at 1.5 times recommended dose of K and minimum at recommended dose of NPK. This study revealed that sUV-B radiation negatively affected the radish plants by reducing the photosynthetic efficiency and increasing LPO. The plants grown at 1.5 times recommended dose of NPK/N/K could not enhance antioxidative potential to the extent as recorded at recommended dose of NPK and hence showed more sensitivity to sUV-B. Copyright © Physiologia Plantarum 2012.

  16. Evaluating the growth parameters of soybean in response to plant growth promoting fungi under Mazandaran climate conditions

    Directory of Open Access Journals (Sweden)

    mohammad yazdani

    2016-05-01

    Full Text Available Abstract In low-input cropping systems, the natural roles of microorganisms in maintaining soil fertility may be more important than conventional system. In order to investigate the effects of plant growth promoting fungi on improvement of growth and development in soybean (cv: JK an experiment was conducted at the research farm of Sari Agricultural Sciences and Natural Resources University during the 2011-2012 growing seasons. Treatments were arranged in a factorial experiment based a completely randomized block design with three replications. The first factor was six levels of fungi: inoculation T. harzianum and AMF genus Glumus: G. mosseae, G. intraradices, and co-inoculation of T. harzianum + G. mosseae, T. harzianum + G. intraradices and non-inoculation (control. The second factor was three levels of phosphorus (0, 70 and 140 kg.ha-1 from superphosphate trip. Results showed that inoculation of T. harzianum and G. mosseae significantly had maximum chlorophyll content up to 17% and 16% at reduced phosphorus dosage (70 kg.ha-1 and conventional phosphorus dosage as compared to the control respectively. The greatest effect was recorded at reduced phosphorus dosage (70 kg.ha-1 and conventional phosphorus dosage significant increase in terms of chlorophyll content. In addition, the dry weights and chlorophyll content of soybean plants in reduced phosphorous dosage (70 kg.ha-1 and co-inoculated with T. harzianum + G. mosseae as well as conventional phosphorous dosage were significantly higher than the non-inoculated plants. In this experiment, at reduce phosphate fertilizer (P0%: 0 treatment, not affected of plant growth promoting fungi compared to control. But, reduced phosphorous dosage (70 kg.ha-1 was more affected.

  17. O-acetylserine (thiol) lyase activity in Phragmites and Typha plants under cadmium and NaCl stress conditions and the involvement of ABA in the stress response.

    Science.gov (United States)

    Fediuc, Erika; Lips, S Herman; Erdei, László

    2005-08-01

    The roles of O-acetylserine (thiol) lyase (OASTL, EC 4.2.99.8) and abscisic (ABA) acid in stress responses to NaCl and cadmium treatments were investigated in Typha latifolia L. and Phragmites australis (Cav.) Trin. ex Steudel plants. OASTL activity increased under stress (25-300 microM Cd, 100mM NaCl, 1 microM ABA) in both Typha and Phragmites mainly in roots, contributing substantially to satisfy the higher demand of cysteine for adaptation and protection. The earliest significant responses in intact roots were recorded after 12-24 h of Cd treatments, but different levels of stimulation were also observed after 3 and 7 days of exposure. The OASTL activity responses of Phragmites to salinity (100mM NaCl) were higher than those of Typha. Cysteine synthesis in Typha is much higher than in Phragmites, which supports the efficiency of the thiol-metabolism-based protection shown in Typha. Exogenous ABA increased OASTL activity in both species. Cd treatments led to increased ABA levels in roots. Phragmites showed higher ABA levels compared to Typha. The increase of ABA content indicates the involvement of this phytohormone in early stress responses, while the stimulation of OASTL following the ABA application suggests that ABA has a role in an OASTL activation pathway.

  18. Responses of Rapid Viscoanalyzer Profile and Other Rice Grain Qualities to Exogenously Applied Plant Growth Regulators under High Day and High Night Temperatures.

    Science.gov (United States)

    Fahad, Shah; Hussain, Saddam; Saud, Shah; Hassan, Shah; Chauhan, Bhagirath Singh; Khan, Fahad; Ihsan, Muhammad Zahid; Ullah, Abid; Wu, Chao; Bajwa, Ali Ahsan; Alharby, Hesham; Amanullah; Nasim, Wajid; Shahzad, Babar; Tanveer, Mohsin; Huang, Jianliang

    2016-01-01

    High-temperature stress degrades the grain quality of rice; nevertheless, the exogenous application of plant growth regulators (PGRs) might alleviate the negative effects of high temperatures. In the present study, we investigated the responses of rice grain quality to exogenously applied PGRs under high day temperatures (HDT) and high night temperatures (HNT) under controlled conditions. Four different combinations of ascorbic acid (Vc), alpha-tocopherol (Ve), brassinosteroids (Br), methyl jasmonates (MeJA) and triazoles (Tr) were exogenously applied to two rice cultivars (IR-64 and Huanghuazhan) prior to the high-temperature treatment. A Nothing applied Control (NAC) was included for comparison. The results demonstrated that high-temperature stress was detrimental for grain appearance and milling qualities and that both HDT and HNT reduced the grain length, grain width, grain area, head rice percentage and milled rice percentage but increased the chalkiness percentage and percent area of endosperm chalkiness in both cultivars compared with ambient temperature (AT). Significantly higher grain breakdown, set back, consistence viscosity and gelatinization temperature, and significantly lower peak, trough and final viscosities were observed under high-temperature stress compared with AT. Thus, HNT was more devastating for grain quality than HDT. The exogenous application of PGRs ameliorated the adverse effects of high temperature in both rice cultivars, and Vc+Ve+MejA+Br was the best combination for both cultivars under high temperature stress.

  19. Responses of Rapid Viscoanalyzer Profile and Other Rice Grain Qualities to Exogenously Applied Plant Growth Regulators under High Day and High Night Temperatures.

    Directory of Open Access Journals (Sweden)

    Shah Fahad

    Full Text Available High-temperature stress degrades the grain quality of rice; nevertheless, the exogenous application of plant growth regulators (PGRs might alleviate the negative effects of high temperatures. In the present study, we investigated the responses of rice grain quality to exogenously applied PGRs under high day temperatures (HDT and high night temperatures (HNT under controlled conditions. Four different combinations of ascorbic acid (Vc, alpha-tocopherol (Ve, brassinosteroids (Br, methyl jasmonates (MeJA and triazoles (Tr were exogenously applied to two rice cultivars (IR-64 and Huanghuazhan prior to the high-temperature treatment. A Nothing applied Control (NAC was included for comparison. The results demonstrated that high-temperature stress was detrimental for grain appearance and milling qualities and that both HDT and HNT reduced the grain length, grain width, grain area, head rice percentage and milled rice percentage but increased the chalkiness percentage and percent area of endosperm chalkiness in both cultivars compared with ambient temperature (AT. Significantly higher grain breakdown, set back, consistence viscosity and gelatinization temperature, and significantly lower peak, trough and final viscosities were observed under high-temperature stress compared with AT. Thus, HNT was more devastating for grain quality than HDT. The exogenous application of PGRs ameliorated the adverse effects of high temperature in both rice cultivars, and Vc+Ve+MejA+Br was the best combination for both cultivars under high temperature stress.

  20. Differential effects of Pseudomonas mendocina and Glomus intraradices on lettuce plants physiological response and aquaporin PIP2 gene expression under elevated atmospheric CO2 and drought.

    Science.gov (United States)

    Alguacil, Maria Del Mar; Kohler, Josef; Caravaca, Fuensanta; Roldán, Antonio

    2009-11-01

    Arbuscular mycorrhizal (AM) symbiosis and plant-growth-promoting rhizobacterium (PGPR) can alleviate the effects of water stress in plants, but it is unknown whether these benefits can be maintained at elevated CO2. Therefore, we carried out a study where seedlings of Lactuca sativa were inoculated with the AM fungus (AMF) Glomus intraradices N.C. Schenk & G.S. Sm. or the PGPR Pseudomonas mendocina Palleroni and subjected to two levels of watering and two levels of atmospheric CO2 to ascertain their effects on plant physiological parameters and gene expression of one PIP aquaporin in roots. The inoculation with PGPR produced the greatest growth in lettuce plants under all assayed treatments as well as the highest foliar potassium concentration and leaf relative water content under elevated [CO2] and drought. However, under such conditions, the PIP2 gene expression remained almost unchanged. G. intraradices increased significantly the AMF colonization, foliar phosphorus concentration and leaf relative water content in plants grown under drought and elevated [CO2]. Under drought and elevated [CO2], the plants inoculated with G. intraradices showed enhanced expression of the PIP2 gene as compared to P. mendocina or control plants. Our results suggest that both microbial inoculation treatments could help to alleviate drought at elevated [CO2]. However, the PIP2 gene expression was increased only by the AMF but not by the PGPR under these conditions.

  1. Plant response to butterfly eggs

    NARCIS (Netherlands)

    Griese, Eddie; Dicke, Marcel; Hilker, Monika; Fatouros, Nina E.

    2017-01-01

    Plants employ various defences killing the insect attacker in an early stage. Oviposition by cabbage white butterflies (Pieris spp.) on brassicaceous plants, including Brassica nigra, induces a hypersensitive response (HR) - like leaf necrosis promoting desiccation of eggs. To gain a deeper insight

  2. Responses of plants to air pollution

    National Research Council Canada - National Science Library

    Mudd, J. Brian; Kozlowski, T. T

    1975-01-01

    .... KOZLOWSKI Pollution, 1975 ELROY L. RICE. Allelopathy, (Eds.). Fire and Ecosystems, 1974 (Eds.). Responses of Plants to Air Responses of Plants to Air PollutionRESPONSES OF PLANTS TO AIR POLLUTION E...

  3. Morphological and Physiological Responses of Strawberry Plants to Water Stress

    OpenAIRE

    Klamkowski, Krzysztof; Treder, Waldemar

    2007-01-01

    The most of previous studies have been focused on the effect of water stress on plant yielding. However, the conditions in which plants grow from the moment of planting might affect their morphology and physiological response. The aim of this study was to examine the effect of water deficiency on growth and plant physiological response of strawberry (Fragaria x ananassa Duch. cv. ‘Salut’) under greenhouse conditions. The plants were grown in plastic containers filled with peat substratum. Wat...

  4. Additional insights into the adaptation of cotton plants under abiotic ...

    African Journals Online (AJOL)

    Abiotic stress is the primary cause of crop losses worldwide. In addition to protein coding genes, microRNAs (miRNAs) have emerged as important players in plant stress responses. Though miRNAs are key in regulating many aspects of plant developmental plasticity under abiotic stresses, very few information are available ...

  5. Plant responses to multiple herbivory

    NARCIS (Netherlands)

    Li, Yehua

    2016-01-01

    This thesis explores whether aphid-infestation interferes with the plant response to chewing herbivores and whether this impacts performance and behaviour of individual chewing insect herbivores and their natural enemies, as well as the entire insect community. I investigated this using three wild

  6. Assessment of filtration efficiency and physiological responses of selected plant species to indoor air pollutants (toluene and 2-ethylhexanol) under chamber conditions.

    Science.gov (United States)

    Hörmann, Vanessa; Brenske, Klaus-Reinhard; Ulrichs, Christian

    2018-01-01

    Three common plant species (Dieffenbachia maculata, Spathiphyllum wallisii, and Asparagus densiflorus) were tested against their capacity to remove the air pollutants toluene (20.0 mg m -3 ) and 2-ethylhexanol (14.6 mg m -3 ) under light or under dark in chamber experiments of 48-h duration. Results revealed only limited pollutant filtration capabilities and indicate that aerial plant parts of the tested species are only of limited value for indoor air quality improvement. The removal rate constant ranged for toluene from 3.4 to 5.7 L h -1  m -2 leaf area with no significant differences between plant species or light conditions (light/dark). The values for 2-ethylhexanol were somewhat lower, fluctuating around 2 L h -1  m -2 leaf area for all plant species tested, whereas differences between light and dark were observed for two of the three species. In addition to pollutant removal, CO 2 fixation/respiration and transpiration as well as quantum yield were evaluated. These physiological characteristics seem to have no major impact on the VOC removal rate constant. Exposure to toluene or 2-ethylhexanol revealed no or only minor effects on D. maculata and S. wallisii. In contrast, a decrease in quantum yield and CO 2 fixation was observed for A. densiflorus when exposed to 2-ethylhexanol or toluene under light, indicating phytotoxic effects in this species.

  7. Plant responses to metal toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Briat, J.F. [Montpellier-2 Univ., 34 (France). Biochimie et physiologie moleculaire des plantes, CNRS, URA 2133; Lebrun, M. [Montpellier-2 Univ., 34 (France). Biochimie et physiologie vegetale appliquee

    1999-01-01

    Increased metal concentration in the soils, up to toxic levels, is becoming an important environmental problem. Safety rule evolution will require solutions in order to cope with food safety rules, and to freeze metal leakage from heavily metal-poisoned soils, such as those from industrial fallows. In this context, plants could serve to develop bio-assays in order to promote new standards, more realistic than the mass of a given metal per kg of soil, that does not consider the metal bio-disponibility. Plants could also be used for phyto-extraction and/or phyto-stabilization. To reach these objectives, a genetic approach could be useful to generate metal-tolerant plants with enough biomass. In this work is more particularly studied the plant responses to metal toxicity. Metal toxicity for living organisms involves oxidative and /or genotoxic mechanisms. Plant protection against metal toxicity occurs, at least in part, through control of root metal uptake and of long distance metal transport. Inside cells, proteins such as ferritins and metallothioneins, and glutathione-derived peptides named phyto-chelatins, participate in excess metal storage and detoxification. Low molecular weight organic molecules, mainly organic acids and amino acids and their derivatives, also play an important role in plant metal homeostasis. When these systems are overloaded, oxidative stress defense mechanisms are activated. Molecular and cellular knowledge of these processes will be necessary to improve plant metal resistance. Occurrence of naturally tolerant plants which hyper accumulate metals provides helpful tools for this research. (authors) 130 refs.

  8. Canopy Apparent Photosynthetic Characteristics and Yield of Two Spike-Type Wheat Cultivars in Response to Row Spacing under High Plant Density.

    Science.gov (United States)

    Liu, Tiening; Wang, Zhenlin; Cai, Tie

    2016-01-01

    In northern China, large-spike wheat (Triticum aestivum L) is considered to have significant potential for increasing yields due to its greater single-plant productivity despite its lower percentage of effective tillers, and increasing the plant density is an effective means of achieving a higher grain yield. However, with increases in plant density, the amount of solar radiation intercepted by lower strata leaves is decreased and the rate of leaf senescence is accelerated. Row spacing can be manipulated to optimize the plant spatial distribution under high plant density, therefore improving light conditions within the canopy. Consequently, field experiments were conducted from 2010 to 2012 to investigate whether changes in row spacing under high plant density led to differences in canopy apparent photosynthesis (CAP), individual leaf photosynthesis and grain yield. Two different spike-type winter wheat cultivars, Jimai22 (a small-spike cultivar as a control cultivar) and Wennong6 (a large-spike cultivar), were grown at a constant plant density of 3,600,000 plants ha(-1) (a relatively higher plant density) over a wide range of row spacing as follows: 5-cm row spacing (R0), 15-cm row spacing (R1), 25-cm conventional row spacing (R2), and 35-cm row spacing (R3). The two-year investigations revealed that increased row spacing exhibited a significantly higher light transmission ratio (LT), which improved light conditions within the canopy; however, excessive light leakage losses in R2 and R3 treatments were not favorable to improved irradiation energy utilization efficiency. Aboveground biomass accumulation was influenced by row spacing. Two spike-type wheat accumulated greater biomass under 15-cm row spacing compared to other row spacing treatments, although a markedly improved photosynthetic rate (PN), effective quantum yield of photosystem II (ΦPSII) and maximal efficiency of photosystem II photochemistry (Fv/Fm) in the penultimate and third leaves were observed in

  9. Canopy Apparent Photosynthetic Characteristics and Yield of Two Spike-Type Wheat Cultivars in Response to Row Spacing under High Plant Density

    Science.gov (United States)

    Cai, Tie

    2016-01-01

    In northern China, large-spike wheat (Triticum aestivum L) is considered to have significant potential for increasing yields due to its greater single-plant productivity despite its lower percentage of effective tillers, and increasing the plant density is an effective means of achieving a higher grain yield. However, with increases in plant density, the amount of solar radiation intercepted by lower strata leaves is decreased and the rate of leaf senescence is accelerated. Row spacing can be manipulated to optimize the plant spatial distribution under high plant density, therefore improving light conditions within the canopy. Consequently, field experiments were conducted from 2010 to 2012 to investigate whether changes in row spacing under high plant density led to differences in canopy apparent photosynthesis (CAP), individual leaf photosynthesis and grain yield. Two different spike-type winter wheat cultivars, Jimai22 (a small-spike cultivar as a control cultivar) and Wennong6 (a large-spike cultivar), were grown at a constant plant density of 3,600,000 plants ha–1 (a relatively higher plant density) over a wide range of row spacing as follows: 5-cm row spacing (R0), 15-cm row spacing (R1), 25-cm conventional row spacing (R2), and 35-cm row spacing (R3). The two-year investigations revealed that increased row spacing exhibited a significantly higher light transmission ratio (LT), which improved light conditions within the canopy; however, excessive light leakage losses in R2 and R3 treatments were not favorable to improved irradiation energy utilization efficiency. Aboveground biomass accumulation was influenced by row spacing. Two spike-type wheat accumulated greater biomass under 15-cm row spacing compared to other row spacing treatments, although a markedly improved photosynthetic rate (PN), effective quantum yield of photosystem II (ΦPSII) and maximal efficiency of photosystem II photochemistry (Fv/Fm) in the penultimate and third leaves were observed in

  10. Abiotic stress signaling and responses in plants

    Science.gov (United States)

    Zhu, Jian-Kang

    2016-01-01

    Summary As sessile organisms, plants must cope with abiotic stress such as soil salinity, drought, and extreme temperatures. Core stress signaling pathways involve protein kinases related to the yeast SNF1 and mammalian AMPK, suggesting that stress signaling in plants evolved from energy sensing. Stress signaling regulates proteins critical for ion and water transport and for metabolic and gene-expression reprogramming to bring about ionic and water homeostasis and cellular stability under stress conditions. Understanding stress signaling and responses will increase our ability to improve stress resistance in crops to achieve agricultural sustainability and food security for a growing world population. PMID:27716505

  11. Searching iron sensors in plants by exploring the link among 2’-OG-dependent dioxygenases, the iron deficiency response and metabolic adjustments occurring under iron deficiency

    Directory of Open Access Journals (Sweden)

    GIANPIERO eVIGANI

    2013-05-01

    Full Text Available Knowledge accumulated on the regulation of iron (Fe homeostasis, its intracellular trafficking and transport across various cellular compartments and organs in plants; storage proteins, transporters and transcription factors involved in Fe metabolism have been analysed in detail in recent years. However, the key sensor(s of cellular plant Fe status triggering the long-distance shoot-root signalling and leading to the root Fe-deficiency responses is (are still unknown. Local Fe sensing is also a major task for roots, for adjusting the internal Fe requirements to external Fe availability: how such sensing is achieved and how it leads to metabolic adjustments in case of nutrient shortage, is mostly unknown. Two proteins belonging to the 2′-OG dependent dioxygenases family accumulate several folds in Fe-deficient Arabidopsis roots. Such proteins require Fe(II as enzymatic cofactor; one of their subgroups, the HIF-P4H (Hypoxia Inducible Factor- Prolyl 4-Hydroxylase, is an effective oxygen sensor in animal cells. We envisage here the possibility that some members of the 2′-OG dioxygenase family may be involved in the Fe-deficiency response and in the metabolic adjustments to Fe deficiency or even in sensing Fe, in plant cells.

  12. Arbuscular mycorrhiza effects on plant performance under osmotic stress.

    Science.gov (United States)

    Santander, Christian; Aroca, Ricardo; Ruiz-Lozano, Juan Manuel; Olave, Jorge; Cartes, Paula; Borie, Fernando; Cornejo, Pablo

    2017-10-01

    At present, drought and soil salinity are among the most severe environmental stresses that affect the growth of plants through marked reduction of water uptake which lowers water potential, leading to osmotic stress. In general, osmotic stress causes a series of morphological, physiological, biochemical, and molecular changes that affect plant performance. Several studies have found that diverse types of soil microorganisms improve plant growth, especially when plants are under stressful conditions. Most important are the arbuscular mycorrhizal fungi (AMF) which form arbuscular mycorrhizas (AM) with approximately 80% of plant species and are present in almost all terrestrial ecosystems. Beyond the well-known role of AM in improving plant nutrient uptake, the contributions of AM to plants coping with osmotic stress merit analysis. With this review, we describe the principal direct and indirect mechanisms by which AM modify plant responses to osmotic stress, highlighting the role of AM in photosynthetic activity, water use efficiency, osmoprotectant production, antioxidant activities, and gene expression. We also discuss the potential for using AMF to improve plant performance under osmotic stress conditions and the lines of research needed to optimize AM use in plant production.

  13. Wheat and barley dehydrins under cold, drought and salinity - what can LEA-II proteins tell us about plant stress response?

    Directory of Open Access Journals (Sweden)

    Klára eKosová

    2014-07-01

    Full Text Available Dehydrins as a group of Late embryogenesis abundant II (LEA-II proteins represent important dehydration-inducible proteins whose accumulation is induced by developmental processes (embryo maturation as well as by several abiotic stress factors (low temperatures, drought, salinity. In the review, an overview of studies aimed at investigation of dehydrin accumulation patterns at transcript and protein levels as well as their possible functions in common wheat (Triticum aestivum, durum wheat (Triticum durum and barley (Hordeum vulgare plants exposed to various abiotic stress factors (cold, frost, drought, salinity is provided. Possible roles of dehydrin proteins in an acquisition and maintenance of an enhanced frost tolerance are analysed in the context of plant developmental processes (vernalization. Quantitative and qualitative differences as well as posttranslational modifications in accumulated dehydrin proteins between barley cultivars revealing differential tolerance to drought and salinity are also discussed. Current knowledge on dehydrin role in wheat and barley response to major dehydrative stresses is summarized and the major challenges in dehydrin research are outlined.

  14. Wheat and barley dehydrins under cold, drought, and salinity - what can LEA-II proteins tell us about plant stress response?

    Science.gov (United States)

    Kosová, Klára; Vítámvás, Pavel; Prášil, Ilja T

    2014-01-01

    Dehydrins as a group of late embryogenesis abundant II proteins represent important dehydration-inducible proteins whose accumulation is induced by developmental processes (embryo maturation) as well as by several abiotic stress factors (low temperatures, drought, salinity). In the review, an overview of studies aimed at investigation of dehydrin accumulation patterns at transcript and protein levels as well as their possible functions in common wheat (Triticum aestivum), durum wheat (T. durum), and barley (Hordeum vulgare) plants exposed to various abiotic stress factors (cold, frost, drought, salinity) is provided. Possible roles of dehydrin proteins in an acquisition and maintenance of an enhanced frost tolerance are analyzed in the context of plant developmental processes (vernalization). Quantitative and qualitative differences as well as post-translational modifications in accumulated dehydrin proteins between barley cultivars revealing differential tolerance to drought and salinity are also discussed. Current knowledge on dehydrin role in wheat and barley response to major dehydrative stresses is summarized and the major challenges in dehydrin research are outlined.

  15. Wheat and barley dehydrins under cold, drought, and salinity – what can LEA-II proteins tell us about plant stress response?

    Science.gov (United States)

    Kosová, Klára; Vítámvás, Pavel; Prášil, Ilja T.

    2014-01-01

    Dehydrins as a group of late embryogenesis abundant II proteins represent important dehydration-inducible proteins whose accumulation is induced by developmental processes (embryo maturation) as well as by several abiotic stress factors (low temperatures, drought, salinity). In the review, an overview of studies aimed at investigation of dehydrin accumulation patterns at transcript and protein levels as well as their possible functions in common wheat (Triticum aestivum), durum wheat (T. durum), and barley (Hordeum vulgare) plants exposed to various abiotic stress factors (cold, frost, drought, salinity) is provided. Possible roles of dehydrin proteins in an acquisition and maintenance of an enhanced frost tolerance are analyzed in the context of plant developmental processes (vernalization). Quantitative and qualitative differences as well as post-translational modifications in accumulated dehydrin proteins between barley cultivars revealing differential tolerance to drought and salinity are also discussed. Current knowledge on dehydrin role in wheat and barley response to major dehydrative stresses is summarized and the major challenges in dehydrin research are outlined. PMID:25071816

  16. The IDA cognitive model for the analysis of nuclear power plant operator response under accident conditions. Part I: problem solving and decision making model

    International Nuclear Information System (INIS)

    Smidts, C.; Shen, S.H.; Mosleh, A.

    1997-01-01

    This paper is the first of a series of papers describing IDA which is a cognitive model for analysing the behaviour of nuclear power plant operators under accident conditions. The domain of applicability of the model is a relatively constrained environment where behaviour is significantly influenced by high levels of training and explicit requirement to follow written procedures. IDA consists of a model for individual operator behaviour and a model for control room operating crew expanded from the individual model. The model and its derivatives such as an error taxonomy and data collection approach has been designed with ultimate objective of becoming a quantitative method for human reliability analysis (HRA) in probabilistic risk assessment (PRA). The present paper gives a description of the main components of IDA such as memory structure, goals, and problem solving and decision making strategies. It also identifies factors that are at the origin of transitions between goals or between strategies. These factors cover the effects of external conditions and psychological state of the operator. The description is generic at first and then made specific to the nuclear power plant environment and more precisely to abnormal conditions

  17. Plant developmental responses to climate change.

    Science.gov (United States)

    Gray, Sharon B; Brady, Siobhan M

    2016-11-01

    Climate change is multi-faceted, and includes changing concentrations of greenhouse gases in the atmosphere, rising temperatures, changes in precipitation patterns, and increasing frequency of extreme weather events. Here, we focus on the effects of rising atmospheric CO 2 concentrations, rising temperature, and drought stress and their interaction on plant developmental processes in leaves, roots, and in reproductive structures. While in some cases these responses are conserved across species, such as decreased root elongation, perturbation of root growth angle and reduced seed yield in response to drought, or an increase in root biomass in shallow soil in response to elevated CO 2 , most responses are variable within and between species and are dependent on developmental stage. These variable responses include species-specific thresholds that arrest development of reproductive structures, reduce root growth rate and the rate of leaf initiation and expansion in response to elevated temperature. Leaf developmental responses to elevated CO 2 vary by cell type and by species. Variability also exists between C 3 and C 4 species in response to elevated CO 2 , especially in terms of growth and seed yield stimulation. At the molecular level, significantly less is understood regarding conservation and variability in molecular mechanisms underlying these traits. Abscisic acid-mediated changes in cell wall expansion likely underlie reductions in growth rate in response to drought, and changes in known regulators of flowering time likely underlie altered reproductive transitions in response to elevated temperature and CO 2 . Genes that underlie most other organ or tissue-level responses have largely only been identified in a single species in response to a single stress and their level of conservation is unknown. We conclude that there is a need for further research regarding the molecular mechanisms of plant developmental responses to climate change factors in general, and

  18. Response of two cultivars of Phaseolus vulgaris L. (French beans) plants exposed to enhanced UV-B radiation under mountain ecosystem.

    Science.gov (United States)

    Raghuvanshi, Rashmi; Sharma, Rajesh Kumar

    2016-01-01

    Enhanced solar ultraviolet-B (UV-B) irradiance resulting from depletion in the ozone layer has the potential to cause detrimental effects on plants. Higher altitudes tend to receive higher doses of ambient UV-B radiation. The present study was carried out to assess the effects of enhanced UV-B (ambient + 10.2 kJ m(-2) day(-1)) radiation on two cultivars of Phaseolus vulgaris L. (cv. Pusa Himlata and Pusa Parvati) at growth, physiological, and biochemical levels grown under mountain ecosystem. The magnitudes of negative effects of enhanced UV-B radiation were found more in Pusa Parvati as compared to Pusa Himlata. Non-enzymatic (total phenolics and flavonoids content) and enzymatic antioxidants (superoxide dismutase, catalase, and peroxidase) were increased in both cultivars at both the ages of growth but increase was found more in Pusa Himlata as compared to Pusa Parvati. The study further showed that the economic yield of Pusa Himlata and Pusa Parvati was decreased by 14 and 44%, respectively, due to enhanced UV-B radiation. The higher decrease in the economic yield of Pusa Parvati depicted that increased amounts of total flavonoids content and stimulation of their antioxidant defense mechanism via increasing the activities of enzymatic antioxidants were not able to completely detoxify the produced reactive oxygen species under enhanced UV-B radiation and made it more sensitive to applied stress. From the present study, it can be concluded that enhanced UV-B radiation in the mountain areas of the Indian Himalayan Regions could be one of the environmental causes for lower yields of agricultural crops. Cultivation of P. vulgaris L. cv. Pusa Himlata should be promoted at higher altitudes of the Indian Himalayan Regions.

  19. Investigation of dryland wheat (Triticum aestivum L. cv. Azar 2 plants response to symbiosis with arbuscular mycorrhiza and mycorrhiza like fungi under different levels of drought stress

    Directory of Open Access Journals (Sweden)

    Y. Yaghoubian

    2016-05-01

    Full Text Available In order to evaluate arbuscular mycorrhiza (Glomuss mossea and mycorrhiza-like (Piriformospora indica effects on yield, yield components and some morphological (cv. Azar 2 traits of wheat (Triticum aestivum L. under water deficit stress, a pot experiment was conducted as factorial experiment based on completely randomized design with four replications. Treatments were drought stress at three levels (FC, -5 and -10 bar and fungi inoculation at four levels (mycorrhiza (AM, mycorrhiza-like (MLF and co-inoculation of AM+MLF and control. Results showed that the water stress significantly decreased 1000-grain weight, spike harvest index, fertility percent of spike, plant height, peduncle and extrusion length and colonization percent while grain density per spike markedly increased. Fungi inoculation significantly improved all studied traits except harvest index, 1000-grain weight and root colonization. Co-inoculation of AM and MLF had the best performance in terms of all mentioned parameters. Interaction effects of fungi and water stress was significant on grain and biological yield, spike and grain number and positively affected by fungi inoculation. Among fungi treatments, however, co-inoculation of AM+MLF had the best performance and recommended for both stress and non stress conditions.

  20. Molecular mechanisms underlying phosphate sensing, signaling, and adaptation in plants.

    Science.gov (United States)

    Zhang, Zhaoliang; Liao, Hong; Lucas, William J

    2014-03-01

    As an essential plant macronutrient, the low availability of phosphorus (P) in most soils imposes serious limitation on crop production. Plants have evolved complex responsive and adaptive mechanisms for acquisition, remobilization and recycling of phosphate (Pi) to maintain P homeostasis. Spatio-temporal molecular, physiological, and biochemical Pi deficiency responses developed by plants are the consequence of local and systemic sensing and signaling pathways. Pi deficiency is sensed locally by the root system where hormones serve as important signaling components in terms of developmental reprogramming, leading to changes in root system architecture. Root-to-shoot and shoot-to-root signals, delivered through the xylem and phloem, respectively, involving Pi itself, hormones, miRNAs, mRNAs, and sucrose, serve to coordinate Pi deficiency responses at the whole-plant level. A combination of chromatin remodeling, transcriptional and posttranslational events contribute to globally regulating a wide range of Pi deficiency responses. In this review, recent advances are evaluated in terms of progress toward developing a comprehensive understanding of the molecular events underlying control over P homeostasis. Application of this knowledge, in terms of developing crop plants having enhanced attributes for P use efficiency, is discussed from the perspective of agricultural sustainability in the face of diminishing global P supplies. © 2014 Institute of Botany, Chinese Academy of Sciences.

  1. Hypoxia affects cellular responses to plant extracts.

    Science.gov (United States)

    Liew, Sien-Yei; Stanbridge, Eric J; Yusoff, Khatijah; Shafee, Norazizah

    2012-11-21

    Microenvironmental conditions contribute towards varying cellular responses to plant extract treatments. Hypoxic cancer cells are known to be resistant to radio- and chemo-therapy. New therapeutic strategies specifically targeting these cells are needed. Plant extracts used in Traditional Chinese Medicine (TCM) can offer promising candidates. Despite their widespread usage, information on their effects in hypoxic conditions is still lacking. In this study, we examined the cytotoxicity of a series of known TCM plant extracts under normoxic versus hypoxic conditions. Pereskia grandifolia, Orthosiphon aristatus, Melastoma malabathricum, Carica papaya, Strobilanthes crispus, Gynura procumbens, Hydrocotyle sibthorpioides, Pereskia bleo and Clinacanthus nutans leaves were dried, blended into powder form, extracted in methanol and evaporated to produce crude extracts. Human Saos-2 osteosarcoma cells were treated with various concentrations of the plant extracts under normoxia or hypoxia (0.5% oxygen). 24h after treatment, an MTT assay was performed and the IC(50) values were calculated. Effect of the extracts on hypoxia inducible factor (HIF) activity was evaluated using a hypoxia-driven firefly luciferase reporter assay. The relative cytotoxicity of each plant extract on Saos-2 cells was different in hypoxic versus normoxic conditions. Hypoxia increased the IC(50) values for Pereskia grandifola and Orthosiphon aristatus extracts, but decreased the IC(50) values for Melastoma malabathricum and Carica papaya extracts. Extracts of Strobilanthes crispus, Gynura procumbens, Hydrocotyle sibthorpioides had equivalent cytotoxic effects under both conditions. Pereskia bleo and Clinacanthus nutans extracts were not toxic to cells within the concentration ranges tested. The most interesting result was noted for the Carica papaya extract, where its IC(50) in hypoxia was reduced by 3-fold when compared to the normoxic condition. This reduction was found to be associated with HIF

  2. Plant Cell Adaptive Responses to Microgravity

    Science.gov (United States)

    Kordyum, Elizabeth; Kozeko, Liudmyla; Talalaev, Alexandr

    simulated microgravity and temperature elevation have different effects on the small HSP genes belonging to subfamilies with different subcellular localization: cytosol/nucleus - PsHSP17.1-CII and PsHSP18.1-CI, cloroplasts - PsHSP26.2-Cl, endoplasmatic reticulum - PsHSP22.7-ER and mitochondria - PsHSP22.9-M: unlike high temperature, clinorotation does not cause denaturation of cell proteins, that confirms the sHSP chaperone function. Dynamics of investigated gene expression in pea seedlings growing 5 days after seed germination under clinorotation was similar to that in the stationary control. Similar patterns in dynamics of sHSP gene expression in the stationary control and under clinorotation may be one of mechanisms providing plant adaptation to simulated microgravity. It is pointed that plant cell responses in microgravity and under clinorotation vary according to growth phase, physiological state, and taxonomic position of the object. At the same time, the responses have, to some degree, a similar character reflecting the changes in cell organelle functional load. Thus, next certain changes in the structure and function of plant cells may be considered as adaptive: 1) an increase in the unsaturated fatty acid content in the plasmalemma, 2) rearrangements of organelle ultrastructure and an increase in their functional load, 3) an increase in cortical F-actin under destabilization of tubulin microtubules, 4) the level of gene expression and synthesis of heat shock proteins, 5) alterations of the enzyme and antioxidant system activity. The dynamics of these patterns demonstrated that the adaptation occurs on the principle of self-regulating systems in the limits of physiological norm reaction. The very importance of changed expression of genes involved in different cellular processes, especially HSP genes, in cell adaptation to altered gravity is discussed.

  3. Variation in Plant Response to Herbivory Underscored by Functional Traits.

    Science.gov (United States)

    Reese, Aspen T; Ames, Gregory M; Wright, Justin P

    2016-01-01

    The effects of herbivory can shape plant communities and evolution. However, the many forms of herbivory costs and the wide variation in herbivory pressure, including across latitudinal gradients, can make predicting the effects of herbivory on different plant species difficult. Functional trait approaches may aid in contextualizing and standardizing the assessment of herbivory impacts. Here we assessed the response of 26 old-field plant species to simulated defoliation in a greenhouse setting by measuring whole plant and leaf level traits in control and treated individuals. Simulated defoliation had no significant effects on any plant traits measured. However, the baseline leaf level traits of healthy plants consistently predicted the log response ratio for these species whole plant response to defoliation. The latitudinal mid-point of species' distributions was also significantly correlated with aboveground biomass and total leaf area responses, with plants with a more northern distribution being more negatively impacted by treatment. These results indicate that even in the absence of significant overall impacts, functional traits may aid in predicting variability in plant responses to defoliation and in identifying the underlying limitations driving those responses.

  4. Variation in Plant Response to Herbivory Underscored by Functional Traits.

    Directory of Open Access Journals (Sweden)

    Aspen T Reese

    Full Text Available The effects of herbivory can shape plant communities and evolution. However, the many forms of herbivory costs and the wide variation in herbivory pressure, including across latitudinal gradients, can make predicting the effects of herbivory on different plant species difficult. Functional trait approaches may aid in contextualizing and standardizing the assessment of herbivory impacts. Here we assessed the response of 26 old-field plant species to simulated defoliation in a greenhouse setting by measuring whole plant and leaf level traits in control and treated individuals. Simulated defoliation had no significant effects on any plant traits measured. However, the baseline leaf level traits of healthy plants consistently predicted the log response ratio for these species whole plant response to defoliation. The latitudinal mid-point of species' distributions was also significantly correlated with aboveground biomass and total leaf area responses, with plants with a more northern distribution being more negatively impacted by treatment. These results indicate that even in the absence of significant overall impacts, functional traits may aid in predicting variability in plant responses to defoliation and in identifying the underlying limitations driving those responses.

  5. Growth, reproductive phenology and yield responses of a potential biofuel plant, Jatropha curcas grown under projected 2050 levels of elevated CO2.

    Science.gov (United States)

    Kumar, Sumit; Chaitanya, Bharatula S K; Ghatty, Sreenivas; Reddy, Attipalli R

    2014-11-01

    Jatropha (Jatropha curcas) is a non-edible oil producing plant which is being advocated as an alternative biofuel energy resource. Its ability to grow in diverse soil conditions and minimal requirements of essential agronomical inputs compared with other oilseed crops makes it viable for cost-effective advanced biofuel production. We designed a study to investigate the effects of elevated carbon dioxide concentration ([CO(2)]) (550 ppm) on the growth, reproductive development, source-sink relationships, fruit and seed yield of J. curcas. We report, for the first time that elevated CO(2) significantly influences reproductive characteristics of Jatropha and improve its fruit and seed yields. Net photosynthetic rate of Jatropha was 50% higher in plants grown in elevated CO(2) compared with field and ambient CO(2) -grown plants. The study also revealed that elevated CO(2) atmosphere significantly increased female to male flower ratio, above ground biomass and carbon sequestration potential in Jatropha (24 kg carbon per tree) after 1 year. Our data demonstrate that J. curcas was able to sustain enhanced rate of photosynthesis in elevated CO(2) conditions as it had sufficient sink strength to balance the increased biomass yields. Our study also elucidates that the economically important traits including fruit and seed yield in elevated CO(2) conditions were significantly high in J. curcas that holds great promise as a potential biofuel tree species for the future high CO(2) world. © 2014 Scandinavian Plant Physiology Society.

  6. Do plants modulate biomass allocation in response to petroleum pollution?

    Science.gov (United States)

    Nie, Ming; Yang, Qiang; Jiang, Li-Fen; Fang, Chang-Ming; Chen, Jia-Kuan; Li, Bo

    2010-01-01

    Biomass allocation is an important plant trait that responds plastically to environmental heterogeneities. However, the effects on this trait of pollutants owing to human activities remain largely unknown. In this study, we investigated the response of biomass allocation of Phragmites australis to petroleum pollution by a 13CO2 pulse-labelling technique. Our data show that plant biomass significantly decreased under petroleum pollution, but the root–shoot ratio for both plant biomass and 13C increased with increasing petroleum concentration, suggesting that plants could increase biomass allocation to roots in petroleum-polluted soil. Furthermore, assimilated 13C was found to be significantly higher in soil, microbial biomass and soil respiration after soils were polluted by petroleum. These results suggested that the carbon released from roots is rapidly turned over by soil microbes under petroleum pollution. This study found that plants can modulate biomass allocation in response to petroleum pollution. PMID:20484231

  7. Pretreated cheese whey wastewater management by agricultural reuse: chemical characterization and response of tomato plants Lycopersicon esculentum Mill. under salinity conditions.

    Science.gov (United States)

    Prazeres, Ana R; Carvalho, Fátima; Rivas, Javier; Patanita, Manuel; Dôres, Jóse

    2013-10-01

    The agricultural reuse of pretreated industrial wastewater resulting from cheese manufacture is shown as a suitable option for its disposal and management. This alternative presents attractive advantages from the economic and pollution control viewpoints. Pretreated cheese whey wastewater (CWW) has high contents of biodegradable organic matter, salinity and nutrients, which are essential development factors for plants with moderate to elevated salinity tolerance. Five different pretreated CWW treatments (1.75 to 10.02 dS m(-1)) have been applied in the tomato plant growth. Fresh water was used as a control run (average salinity level=1.44 dS m(-1)). Chemical characterization and indicator ratios of the leaves, stems and roots were monitored. The sodium and potassium leaf concentrations increased linearly with the salinity level in both cultivars, Roma and Rio Grande. Similar results were found in the stem sodium content. However, the toxic sodium accumulations in the cv. Roma exceeded the values obtained in the cv. Rio Grande. In this last situation, K and Ca uptake, absorption, transport and accumulation capacities were presented as tolerance mechanisms for the osmotic potential regulation of the tissues and for the ion neutralization. Consequently, Na/Ca and Na/K ratios presented lower values in the cv. Rio Grande. Na/Ca ratio increased linearly with the salinity level in leaves and stems, regardless of the cultivar. Regarding the Na/K ratio, the values demonstrated competition phenomena between the ions for the cv. Rio Grande. Despite the high chloride content of the CWW, no significant differences were observed for this nutrient in the leaves and stems. Thus, no nitrogen deficiency was demonstrated by the interaction NO3(-)/Cl(-). Nitrogen also contributes to maintain the water potential difference between the tissues and the soil. Na, P, Cl and N radicular concentrations were maximized for high salinity levels (≥2.22 dS m(-1)) of the pretreated CWW. © 2013

  8. Regulation of plant stress response by dehydration responsive ...

    African Journals Online (AJOL)

    Plant growth and productivity are greatly affected by environmental stresses such as dehydration, high salinity, low temperature and biotic pathogen infection. Plant adaptation to these environmental stresses is controlled by cascades of molecular networks. The dehydration responsive element binding (DREB) transcription ...

  9. Reduction of seismic response in breeder plants

    International Nuclear Information System (INIS)

    Tajirian, F.F.; Somes, N.F.; Todeschini, R.A.

    1984-01-01

    Thin-walled vessels to be used in the Nuclear Steam Supply Systems (NSSS) of future LMFBR's will be more sensitive to seismic excitation than their equivalents used in conventional LWR plants. Optimization studies of building arrangement have indicated that embedment of future plants may be one feasible strategy for reducing seismic response. This paper presents the results of a three-dimensional soil-structure interaction analysis using the computer program SASSI. Two types of embedded buildings are considered: full embedment of the nuclear island, and embedment of the reactor cavity alone. A comparison, between the response of the embedded structure with that of a plant supported on the surface, indicates that the seismic response at the reactor vessel support ledge can be lowered by embedment of either the entire nuclear island or the reactor cavity alone. This reduction is larger when the plant is embedded in a softer site due to the increased effect of soil-structure interaction

  10. Plant response to heavy metals and organic pollutants in cell culture and at whole plant level

    Energy Technology Data Exchange (ETDEWEB)

    Golan-Goldhirsh, A.; Barazani, O. [Ben-Gurion Univ. of The Negev, The Jacob Blaustein Inst. for Desert Research, Albert Katz Dept. of Dryland Biotechnologies, Desert Plant Biotechnology Lab., Sede Boqer Campus (Israel); Nepovim, A.; Soudek, P.; Vanek, T. [Inst. of Organic Chemistry and Biochemistry (Czech Republic); Smrcek, S.; Dufkova, L.; Krenkova, S. [Faculty of Natural Sciences, Charles Univ. (Czech Republic); Yrjala, K. [Univ. of Helsinki, Dept. of Biosciences, Div. of General Microbiology, Helsinki (Finland); Schroeder, P. [Inst. for Soil Ecology, GSF National Research Center for Environment and Health, Neuherberg, Oberschleissheim (Germany)

    2004-07-01

    Background. Increasing awareness in the last decade concerning environmental quality had prompted research into 'green solutions' for soil and water remediation, progressing from laboratory in vitro experiments to pot and field trials. In vitro cell culture experiments provide a convenient system to study basic biological processes, by which biochemical pathways, enzymatic activity and metabolites can be specifically studied. However, it is difficult to relate cell cultures, calli or even hydroponic experiments to the whole plant response to pollutant stress. In the field, plants are exposed to additional a-biotic and biotic factors, which complicate further plant response. Hence, we often see that in vitro selected species perform poorly under soil and field conditions. Soil physical and chemical properties, plant-mycorrhizal association and soil-microbial activity affect the process of contaminant degradation by plants and/or microorganisms, pointing to the importance of pot and field experiments. Objective. This paper is a joint effort of a group of scientists in COST action 837. It represents experimental work and an overview on plant response to environmental stress from in vitro tissue culture to whole plant experiments in soil. Results. Results obtained from in vitro plant tissue cultures and whole plant hydroponic experiments indicate the phytoremediation potential of different plant species and the biochemical mechanisms involved in plant tolerance. In pot experiments, several selected desert plant species, which accumulated heavy metal in hydroponic systems, succeeded in accumulating the heavy metal in soil conditions as well. Conclusions and recommendations. In vitro plant tissue cultures provide a useful experimental system for the study of the mechanisms involved in the detoxification of organic and heavy metal pollutants. However, whole plant experimental systems, as well as hydroponics followed by pot and field trials, are essential when

  11. Role of ethylene in responses of plants to nitrogen availability.

    Science.gov (United States)

    Khan, M I R; Trivellini, Alice; Fatma, Mehar; Masood, Asim; Francini, Alessandra; Iqbal, Noushina; Ferrante, Antonio; Khan, Nafees A

    2015-01-01

    Ethylene is a plant hormone involved in several physiological processes and regulates the plant development during the whole life. Stressful conditions usually activate ethylene biosynthesis and signaling in plants. The availability of nutrients, shortage or excess, influences plant metabolism and ethylene plays an important role in plant adaptation under suboptimal conditions. Among the plant nutrients, the nitrogen (N) is one the most important mineral element required for plant growth and development. The availability of N significantly influences plant metabolism, including ethylene biology. The interaction between ethylene and N affects several physiological processes such as leaf gas exchanges, roots architecture, leaf, fruits, and flowers development. Low plant N use efficiency (NUE) leads to N loss and N deprivation, which affect ethylene biosynthesis and tissues sensitivity, inducing cell damage and ultimately lysis. Plants may respond differently to N availability balancing ethylene production through its signaling network. This review discusses the recent advances in the interaction between N availability and ethylene at whole plant and different organ levels, and explores how N availability induces ethylene biology and plant responses. Exogenously applied ethylene seems to cope the stress conditions and improves plant physiological performance. This can be explained considering the expression of ethylene biosynthesis and signaling genes under different N availability. A greater understanding of the regulation of N by means of ethylene modulation may help to increase NUE and directly influence crop productivity under conditions of limited N availability, leading to positive effects on the environment. Moreover, efforts should be focused on the effect of N deficiency or excess in fruit trees, where ethylene can have detrimental effects especially during postharvest.

  12. ROLE OF ETHYLENE IN RESPONSES OF PLANTS TO NITROGEN AVAILABILITY

    Directory of Open Access Journals (Sweden)

    M Iqbal R Khan

    2015-10-01

    Full Text Available Ethylene is a plant hormone involved in several physiological processes and regulates the plant development during the whole life. Stressful conditions usually activate ethylene biosynthesis and signalling in plants. The availability of nutrients, shortage or excess, influences plant metabolism and ethylene plays an important role in plant adaptation under suboptimal conditions. Among the plant nutrients, the nitrogen (N is one the most important mineral element required for plant growth and development. The availability of N significantly influences plant metabolism, including ethylene biology. The interaction between ethylene and N affects several physiological process such as leaf gas exchanges, roots architecture, leaf, fruits and flowers development. Low plant N use efficiency leads to N loss and N deprivation, which affect ethylene biosynthesis and tissues sensitivity, inducing cell damage and ultimately lysis. Plants may respond differently to N availability balancing ethylene production through its signalling network. This review discusses the recent advances in the interaction between N availability and ethylene at whole plant and different organ levels, and explores how N availability induces ethylene biology and plant responses. Exogenously applied ethylene seems to cope the stress conditions and improves plant physiological performance. This can be explained considering the expression of ethylene biosynthesis and signalling genes under different N availability. A greater understanding of the regulation of N by means of ethylene modulation may help to increase N use efficiency and directly influence crop productivity under conditions of limited N availability, leading to positive effects on the environment. Moreover, efforts should be focused on the effect of N deficiency or excess in fruit trees, where ethylene can have detrimental effects especially during postharvest.

  13. Facultative grazing and bioturbation by macrodetritivores alter saltmarsh plant-plant interactions under stress

    NARCIS (Netherlands)

    Howison, Ruth A.; Olff, Han; van Puijenbroek, Marinka E. B.; Smit, Christian

    The importance of positive plant-plant interactions is generally suggested to increase towards more stressful conditions, due to mutual stress amelioration between plants. Bioturbating macrodetritivores can also ameliorate stress through bioturbation, but can also become selective herbivores under

  14. Metabolic Reprogramming in Chloroplasts under Heat Stress in Plants.

    Science.gov (United States)

    Wang, Qing-Long; Chen, Juan-Hua; He, Ning-Yu; Guo, Fang-Qing

    2018-03-14

    Increases in ambient temperatures have been a severe threat to crop production in many countries around the world under climate change. Chloroplasts serve as metabolic centers and play a key role in physiological adaptive processes to heat stress. In addition to expressing heat shock proteins that protect proteins from heat-induced damage, metabolic reprogramming occurs during adaptive physiological processes in chloroplasts. Heat stress leads to inhibition of plant photosynthetic activity by damaging key components functioning in a variety of metabolic processes, with concomitant reductions in biomass production and crop yield. In this review article, we will focus on events through extensive and transient metabolic reprogramming in response to heat stress, which included chlorophyll breakdown, generation of reactive oxygen species (ROS), antioxidant defense, protein turnover, and metabolic alterations with carbon assimilation. Such diverse metabolic reprogramming in chloroplasts is required for systemic acquired acclimation to heat stress in plants.

  15. Respostas do feijão-vagem cultivado sob proteção com agrotêxtil em duas densidades de plantas Response of snap beans cultivated in two plant densities under nonwowen protection in Brazil

    Directory of Open Access Journals (Sweden)

    Adalberto Vitor Pereira

    2003-09-01

    yield of two cultivars of snap beans was evaluated. The current work was carried out at an experimental area of the Universidade Estadual de Ponta Grossa, Paraná State, Brazil. The experimental design was a completely randomized in split plots 2x2x2 (cultivars x protection x plant density, with four replications. The cultivars Turmalina and Coralina were sown in March (autumn, 2000, in two plant densities (6.6 and 3.3 pl m-1 under nonwowen protection (PP and natural environment (AN. Early yield, total yield, number and weight of pods were evaluated. The air (Tar and soil temperature amplitudes (Ts under PP and AN were also evaluated. Nonwoven protection and plant density did not influence the early yield. However, the use of nonwoven protection increased yield of 'Turmalina' as a result of higher number of pods per plant, compared with AN. There was no difference between PP and AN on yield of 'Coralina'. The plant density did not influence yield response of 'Turmalina'. On the other hand, 'Coralina' was more productive when cultivated under plant density of 3,3 pl m-1, when compared to 6,6 pl m-1. 'Coralina' was more productive than 'Turmalina' when cultivated under 3,3 pl m-1, however without differences between cultivars under 6,6 pl m-1. Air and soil temperature were higher under PP compared to AN, during the whole cycle of the culture, with medium differences between PP and AN of 2,63 and 1,97ºC, respectively for Tar and Ts. The difference between PP and AN, for Tar and Ts, was higher at the beginning of plant growing and decreased with the development of snap bean.

  16. Comportamento do sorgo granífero em função de diferentes frações da água disponível no solo Grain sorghum responses under several fractions of plant available water

    Directory of Open Access Journals (Sweden)

    Marcia Xavier Peiter

    1996-04-01

    Full Text Available O comportamento morfológico e fisiológico das plantas de sorgo em relação à diferentes níveis de déficit hídrico tem sido caracterizado extensivamente. Entretanto, as respostas são dependentes do grau de severidade e duração do déficit. O objetivo desse experimento foi analisar o comportamento da cultura do sorgo quando submetida a diferentes frações da água disponível no solo. O experimento foi desenvolvido no ano agrícola de 1993/94, em lisímetros de drenagem, protegidos das precipitações pluviométricas através de uma cobertura móvel. A cultivar Agroceres 3001 foi submetida a quatro tratamentos de irrigação. Irrigações foram aplicadas quando a fração da água disponível (FAD, medida na profundidade do solo explorado pelo sistema radicular das plantas, atingia valores inferiores a 0,95, 0,85, 0,75, e 0,65 da FAD, com três repetições. A altura de plantas e o índice de área foliar foram semelhantes para os tratamentos de 0,75, 0,85 e 0,95 da FAD. O manejo da irrigação com a manutenção da FAD a 0,75 e 0,85 apresentaram valores semelhantes para todas as variáveis analisadas. A manutenção da FAD a 0,65 resultou em um menor crescimento das plantas de sorgo, indicando a ocorrência de déficit hídrico.The morphological and physiological behaviour of grain sorghum plants submitted to different water deficit levels has been extensively characterized. However, plant responses are extremelly dependents of the severity and duration of lhe stress. The objective of this experiment was to evaluate the performance of sorghum crop when submitted to different irrigation management levels. This experiment was conducted during 1993/94 growing season in a set of drainage lysimeters under a rain shelter. The sorghum variety Agroceres 3001 was submitted to four irrigation treatments. Irrigations were aplyied when the fraction of plant available water (PAW were lower than 0.95, 0.85, 0.75 and 0.65, with three replications

  17. Dynamic Frequency Response of Wind Power Plants

    DEFF Research Database (Denmark)

    Altin, Müfit

    to maintain sustainable and reliable operation of the power system for these targets, transmission system operators (TSOs) have revised the grid code requirements. Also, the TSOs are planning the future development of the power system with various wind penetration scenarios to integrate more wind power...... according to their grid codes. In these scenarios particularly with high wind power penetration cases, conventional power plants (CPPs) such as old thermal power plants are planned to be replaced with wind power plants (WPPs). Consequently, the power system stability will be affected and the control...... capability of WPPs would be investigated. The objective of this project is to analyze and identify the power system requirements for the synchronizing power support and inertial response control of WPPs in high wind power penetration scenarios. The dynamic frequency response of WPPs is realized...

  18. Light accelerates plant responses to warming.

    Science.gov (United States)

    De Frenne, Pieter; Rodríguez-Sánchez, Francisco; De Schrijver, An; Coomes, David A; Hermy, Martin; Vangansbeke, Pieter; Verheyen, Kris

    2015-08-17

    Competition for light has profound effects on plant performance in virtually all terrestrial ecosystems. Nowhere is this more evident than in forests, where trees create environmental heterogeneity that shapes the dynamics of forest-floor communities(1-3). Observational evidence suggests that biotic responses to both anthropogenic global warming and nitrogen pollution may be attenuated by the shading effects of trees and shrubs(4-9). Here we show experimentally that tree shade is slowing down changes in below-canopy communities due to warming. We manipulated levels of photosynthetically active radiation, temperature and nitrogen, alone and in combination, in a temperate forest understorey over a 3-year period, and monitored the composition of the understorey community. Light addition, but not nitrogen enrichment, accelerated directional plant community responses to warming, increasing the dominance of warmth-preferring taxa over cold-tolerant plants (a process described as thermophilization(6,10-12)). Tall, competitive plants took greatest advantage of the combination of elevated temperature and light. Warming of the forest floor did not result in strong community thermophilization unless light was also increased. Our findings suggest that the maintenance of locally closed canopy conditions could reduce, at least temporarily, warming-induced changes in forest floor plant communities.

  19. The role of ethylene in plants under salinity stress

    Directory of Open Access Journals (Sweden)

    Jian-Jun eTao

    2015-11-01

    Full Text Available Although the roles of ethylene in plant response to salinity and other stresses have been extensively studied, there are still some obscure points left to be clarified. Generally, in Arabidopsis and many other terrestrial plants, ethylene signaling is indispensable for plant rapid response and tolerance to salinity stress. However, a few studies showed that functional knock-out of some ACSs increased plant salinity-tolerance, while overexpression of them caused more sensitivity. This seems to be contradictory to the known opinion that ethylene plays positive roles in salinity response. Differently, ethylene in rice may play negative roles in regulating seedling tolerance to salinity. The main positive ethylene signaling components MHZ7/OsEIN2, MHZ6/OsEIL1 and OsEIL2 all negatively regulate the salinity-tolerance of rice seedlings. Recently, several different research groups all proposed a negative feedback mechanism of coordinating plant growth and ethylene response, in which several ethylene-inducible proteins (including NtTCTP, NEIP2, SAUR76/77/78 and ARGOS act as inhibitors of ethylene response but activators of plant growth. Therefore, in addition to a summary of the general roles of ethylene biosynthesis and signaling in salinity response, this review mainly focused on discussing (i the discrepancies between ethylene biosynthesis and signaling in salinity response, (ii the divergence between rice and Arabidopsis in regulation of salinity response by ethylene, and (iii the possible negative feedback mechanism of coordinating plant growth and salinity response by ethylene.

  20. Nuclear power plant safety under military threats

    International Nuclear Information System (INIS)

    Stritar, A.; Mavko, B.

    1993-01-01

    The Krsko nuclear power plant in Slovenia was probably the first in the world that found itself in the middle of a war region. A number of preventive measures performed during and immediately after the war in summer 1991 by the plant personnel as well as some of related activities of the Reactor Engineering Division of the 'Jozef Stefan' Institute are described. All efforts were aimed at the minimization of the possible public radiological consequences during a military attack. The critical safety functions in such conditions were checked. Concern was further devoted to maintenance of the core cooling in the core and to integrity of the spent fuel pit. The cold shutdown mode was found to be the most appropriate option. After selecting the cold shutdown mode as a most suitable operational state of the plant, further studies of the vulnerability were done. In addition to possible direct damage to structures, that would cause release of radioactivity, two important subjects were considered: AC and DC power supply and the ultimate heat sink. A quick analysis during the crisis has shown that the consequences of a military attack against the plant by jet fighters could be serious, but with the proper preventive measures and preparedness the environmental consequences could be minimized. (Z.S.) 1 fig., 1 ref

  1. Urban Plantings: 'Living Laboratories' for Climate Change Response.

    Science.gov (United States)

    Farrell, Claire; Szota, Christopher; Arndt, Stefan K

    2015-10-01

    Urban plantings are not only valuable resources for understanding 'urban plant physiology' but are 'living laboratories' for understanding plant response to climate change. Therefore, we encourage researchers who currently work in natural ecosystems to consider how urban plantings could enhance their research into plant physiological responses to a changing climate. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Fate of polycyclic aromatic hydrocarbons in plant-soil systems: Plant responses to a chemical stress in the root zone

    Energy Technology Data Exchange (ETDEWEB)

    Hoylman, Anne M. [Univ. of Tennessee, Knoxville, TN (United States)

    1994-01-01

    Under laboratory conditions selected to maximize root uptake, plant tissue distribution of PAH-derived 14C was largely limited to root tissue of Malilotus alba. These results suggest that plant uptake of PAHs from contaminated soil via roots, and translocation to aboveground plant tissues (stems and leaves), is a limited mechanism for transport into terrestrial food chains. However, these data also indicate that root surface sorption of PAHs may be important for plants grown in soils containing elevated concentration PAHs. Root surface sorption of PAHs may be an important route of exposure for plants in soils containing elevated concentrations of PAHS. Consequently, the root-soil interface may be the site of plant-microbial interactions in response to a chemical stress. In this study, evidence of a shift in carbon allocation to the root zone of plants exposed to phenanthrene and corresponding increases in soil respiration and heterotrophic plate counts provide evidence of a plant-microbial response to a chemical stress. The results of this study establish the importance of the root-soil interface for plants growing in PAH contaminated soil and indicate the existence of plant-microbial interactions in response to a chemical stress. These results may provide new avenues of inquiry for studies of plant toxicology, plant-microbial interactions in the rhizosphere, and environmental fates of soil contaminants. In addition, the utilization of plants to enhance the biodegradation of soil contaminants may require evaluation of plant physiological changes and plant shifts in resource allocation.

  3. Grape marc extract acts as elicitor of plant defence responses.

    Science.gov (United States)

    Goupil, Pascale; Benouaret, Razik; Charrier, Olivia; Ter Halle, Alexandra; Richard, Claire; Eyheraguibel, Boris; Thiery, Denis; Ledoigt, Gérard

    2012-07-01

    Plant protection based on novel alternative strategies is a major concern in agriculture to sustain pest management. The marc extract of red grape cultivars reveals plant defence inducer properties. Treatment with grape marc extract efficiently induced hypersensitive reaction-like lesions with cell death evidenced by Evans Blue staining of tobacco leaves. Examination of the infiltration zone and the surrounding areas under UV light revealed the accumulation of autofluorescent compounds. Both leaf infiltration and a foliar spray of the red grape extract on tobacco leaves induced defence gene expression. The PR1 and PR2 target genes were upregulated locally and systemically in tobacco plants following grape marc extract treatment. The grape extract elicited an array of plant defence responses making this natural compound a potential phytosanitary product with a challenging issue and a rather attractive option for sustainable agriculture and environmentally friendly practices.

  4. An untargeted global metabolomic analysis reveals the biochemical changes underlying basal resistance and priming in Solanum lycopersicum, and identifies 1-methyltryptophan as a metabolite involved in plant responses to Botrytis cinerea and Pseudomonas syringae.

    Science.gov (United States)

    Camañes, Gemma; Scalschi, Loredana; Vicedo, Begonya; González-Bosch, Carmen; García-Agustín, Pilar

    2015-10-01

    In this study, we have used untargeted global metabolomic analysis to determine and compare the chemical nature of the metabolites altered during the infection of tomato plants (cv. Ailsa Craig) with Botrytis cinerea (Bot) or Pseudomonas syringae pv. tomato DC3000 (Pst), pathogens that have different invasion mechanisms and lifestyles. We also obtained the metabolome of tomato plants primed using the natural resistance inducer hexanoic acid and then infected with these pathogens. By contrasting the metabolomic profiles of infected, primed, and primed + infected plants, we determined not only the processes or components related directly to plant defense responses, but also inferred the metabolic mechanisms by which pathogen resistance is primed. The data show that basal resistance and hexanoic acid-induced resistance to Bot and Pst are associated with a marked metabolic reprogramming. This includes significant changes in amino acids, sugars and free fatty acids, and in primary and secondary metabolism. Comparison of the metabolic profiles of the infections indicated clear differences, reflecting the fact that the plant's chemical responses are highly adapted to specific attackers. The data also indicate involvement of signaling molecules, including pipecolic and azelaic acids, in response to Pst and, interestingly, to Bot. The compound 1-methyltryptophan was shown to be associated with the tomato-Pst and tomato-Bot interactions as well as with hexanoic acid-induced resistance. Root application of this Trp-derived metabolite also demonstrated its ability to protect tomato plants against both pathogens. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

  5. Plant control impact on IFR power plant passive safety response

    International Nuclear Information System (INIS)

    Vilim, R.B.

    1993-01-01

    A method is described for optimizing the closed-loop plant control strategy with respect to safety margins sustained in the unprotected upset response of a liquid metal reactor. The optimization is performed subject to the normal requirements for reactor startup, load change and compensation for reactivity changes over the cycle. The method provides a formal approach to the process of exploiting the innate self-regulating property of a metal fueled reactor to make it less dependent on operator action and less vulnerable to automatic control system fault and/or operator error

  6. Different Narrow-Band Light Ranges Alter Plant Secondary Metabolism and Plant Defense Response to Aphids.

    Science.gov (United States)

    Rechner, Ole; Neugart, Susanne; Schreiner, Monika; Wu, Sasa; Poehling, Hans-Michael

    2016-10-01

    Light of different wavelengths affects various physiological processes in plants. Short-wavelength radiation (like UV) can activate defense pathways in plants and enhance the biosynthesis of secondary metabolites (such as flavonoids and glucosinolates) responsible for resistance against certain herbivorous insects. The intensity of light-induced, metabolite-based resistance is plant- and insect species-specific and depends on herbivore feeding guild and specialization. In this study, broccoli (Brassica oleracea var. italica) plants were grown for 4 weeks in a climate chamber under conventional fluorescent tubes and were additionally treated with UV-B (310 nm), UV-A (365 or 385 nm), or violet (420 nm) light generated with UV-B tubes or light-emitting diodes (LEDs). The objective was to determine the influence of narrow bandwidths of light (from UV-B to violet) on plant secondary metabolism and on the performance of the cabbage aphid Brevicoryne brassicae (a specialist) and the green peach aphid Myzus persicae (a generalist). Among flavonol glycosides, specific quercetin and kaempferol glycosides increased markedly under UV-B, while among glucosinolates only 4-methoxy-3-indolylmethyl showed a 2-fold increase in plants exposed to UV-B and UV-A. The concentration of 3-indolylmethyl glucosinolate in broccoli plants increased with UV-B treatment. Brevicoryne brassicae adult weights and fecundity were lower on UV-B treated plants compared to UV-A or violet light-treated plants. Adult weights and fecundity of M. persicae were increased under UV-B and UV-A treatments. When specific light wavelengths are used to induce metabolic changes in plants, the specificity of the induced effects on herbivores should be considered.

  7. Crop and medicinal plants proteomics in response to salt stress

    Directory of Open Access Journals (Sweden)

    Keyvan eAghaei

    2013-01-01

    Full Text Available Increasing of world population marks a serious need to create new crop cultivars and medicinal plants with high growth and production at any environmental situations. Among the environmental unfavorable conditions, salinity is the most widespread in the world. Crop production and growth severely decreases under salt stress; however, some crop cultivars show significant tolerance against the negative effects of salinity. Among salt stress responses of crops, proteomic responses play a pivotal role in their ability to cope with it and have become the main center of notification. Many physiological responses are detectable in terms of protein increase and decrease even before physiological responses take place. Thus proteomic approach makes a short cut in the way of inferring how crops response to salt stress. Nowadays many salt-responsive proteins such as heat shock proteins, pathogen related proteins, protein kinases, ascorbate peroxidase, osmotin, ornithine decarboxylase and some transcription factors, have been detected in some major crops which are thought to give them the ability of withstanding against salt stress. Proteomic analysis of medicinal plants also revealed that alkaloid biosynthesis related proteins such as tryptophan synthase, codeinone reductase, strictosidine synthase and 12-oxophytodienoate reductase might have major role in production of secondary metabolites. In this review we are comparing some different or similar proteomic responses of several crops and medicinal plants to salt stress and discuss about the future prospects.

  8. Plant Immune System: Crosstalk Between Responses to Biotic and Abiotic Stresses the Missing Link in Understanding Plant Defence.

    Science.gov (United States)

    Nejat, Naghmeh; Mantri, Nitin

    2017-01-01

    Environmental pollution, global warming and climate change exacerbate the impact of biotic and abiotic stresses on plant growth and yield. Plants have evolved sophisticated defence network, also called innate immune system, in response to ever- changing environmental conditions. Significant progress has been made in identifying the key stress-inducible genes associated with defence response to single stressors. However, relatively little information is available on the signaling crosstalk in response to combined biotic/abiotic stresses. Recent evidence highlights the complex nature of interactions between biotic and abiotic stress responses, significant aberrant signaling crosstalk in response to combined stresses and a degree of overlap, but unique response to each environmental stimulus. Further, the results of simultaneous combined biotic and abiotic stress studies indicate that abiotic stresses particularly heat and drought enhance plant susceptibility to plant pathogens. It is noteworthy that global climate change is predicted to have a negative impact on biotic stress resistance in plants. Therefore, it is vital to conduct plant transcriptome analysis in response to combined stresses to identify general or multiple stress- and pathogen-specific genes that confer multiple stress tolerance in plants under climate change. Here, we discuss the recent advances in our understanding of the molecular mechanisms of crosstalk in response to biotic and abiotic stresses. Pinpointing both, common and specific components of the signaling crosstalk in plants, allows identification of new targets and development of novel methods to combat biotic and abiotic stresses under global climate change.

  9. Traits underlying community consequences of plant intra-specific diversity.

    Directory of Open Access Journals (Sweden)

    Luis Abdala-Roberts

    Full Text Available A plant's performance and interactions with other trophic levels are recorgnized to be contingent upon plant diversity and underlying associational dynamics, but far less is known about the plant traits driving such phenomena. We manipulated diversity in plant traits using pairs of plant and a substitutive design to elucidate the mechanisms underlying diversity effects operating at a fine spatial scale. Specifically, we measured the effects of diversity in sex (sexual monocultures vs. male and female genotypes together and growth rate (growth rate monocultures vs. fast- and slow-growing genotypes together on growth of the shrub Baccharis salicifolia and on above- and belowground consumers associated with this plant. We compared effects on associate abundance (# associates per plant vs. density (# associates per kg plant biomass to elucidate the mechanisms underlying diversity effects; effects on abundance but not density suggest diversity effects are mediated by resource abundance (i.e. plant biomass alone, whereas effects on density suggest diversity effects are mediated by plant-based heterogeneity or quality. Sexual diversity increased root growth but reduced the density (but not abundance of the dietary generalist aphid Aphis gossypii and its associated aphid-tending ants, suggesting sex mixtures were of lower quality to this herbivore (e.g. via reduced plant quality, and that this effect indirectly influenced ants. Sexual diversity had no effect on the abundance or density of parasitoids attacking A. gossypii, the dietary specialist aphid Uroleucon macolai, or mycorrhizae. In contrast, growth rate diversity did not influence plant growth or any associates except for the dietary specialist aphid U. macolai, which increased in both abundance and density at high diversity, suggesting growth rate mixtures were of higher quality to this herbivore. These results highlight that plant associational and diversity effects on consumers are contingent

  10. Unraveling plant responses to bacterial pathogens through proteomics

    KAUST Repository

    Zimaro, Tamara

    2011-11-03

    Plant pathogenic bacteria cause diseases in important crops and seriously and negatively impact agricultural production. Therefore, an understanding of the mechanisms by which plants resist bacterial infection at the stage of the basal immune response or mount a successful specific R-dependent defense response is crucial since a better understanding of the biochemical and cellular mechanisms underlying these interactions will enable molecular and transgenic approaches to crops with increased biotic resistance. In recent years, proteomics has been used to gain in-depth understanding of many aspects of the host defense against pathogens and has allowed monitoring differences in abundance of proteins as well as posttranscriptional and posttranslational processes, protein activation/inactivation, and turnover. Proteomics also offers a window to study protein trafficking and routes of communication between organelles. Here, we summarize and discuss current progress in proteomics of the basal and specific host defense responses elicited by bacterial pathogens. Copyright 2011 Tamara Zimaro et al.

  11. Gas exchange under water : acclimation of terrestrial plants to submergence

    OpenAIRE

    Mommer, Liesje

    2005-01-01

    Gas exchange between the plant and the environment is severely hampered when plants are submerged, leading to oxygen and energy deficits. A straightforward way to reduce these shortages of oxygen and carbohydrates would be prolonged photosynthesis under water, but this has received only little attention. This thesis, therefore, aims to investigate in depth the effects of acclimation to submergence on underwater gas exchange capacity of terrestrial plants. It elucidates the beneficial effects ...

  12. Gas exchange under water : acclimation of terrestrial plants to submergence

    NARCIS (Netherlands)

    Mommer, Liesje

    2005-01-01

    Gas exchange between the plant and the environment is severely hampered when plants are submerged, leading to oxygen and energy deficits. A straightforward way to reduce these shortages of oxygen and carbohydrates would be prolonged photosynthesis under water, but this has received only little

  13. Assessment of microbial diversity under arid plants by culture ...

    African Journals Online (AJOL)

    Assessment of microbial diversity under arid plants by culture-dependent and culture-independent approaches. ... African Journal of Biotechnology ... In this work, microbial community structure of two distinct arid plants like ker (Capparis deciduas) and pearl millet (Pennisetum glaucum) was assessed and defined by ...

  14. A Latex Metabolite Benefits Plant Fitness under Root Herbivore Attack

    NARCIS (Netherlands)

    Huber, M.; Epping, Janina; Schulze Gronover, C.; Fricke, Julia; Aziz, Zohra; Brillatz, Théo; Swyers, Michael; Kollner, T.G.; Vogel, H.; Hammerbacher, Almuth; Triebwasser-Freese, Daniella; Robert, Christelle A.M.; Verhoeven, K.J.F.; Preite, V.; Gershenzon, J.; Erb, M.

    2016-01-01

    Plants produce large amounts of secondary metabolites in their shoots and roots and store them in specialized secretory structures. Although secondary metabolites and their secretory structures are commonly assumed to have a defensive function, evidence that they benefit plant fitness under

  15. An ethnobotanical study of medicinal plants used in villages under ...

    African Journals Online (AJOL)

    An ethnobotanical study of medicinal plants used in villages under Jongilanga Tribal Council, Mpumalanga, South Africa. Thilivhali Emmanuel Tshikalange, Boikanyo Calvin Mophuting, James Mahore, Stefan Winterboer, Namrita Lall ...

  16. Plant cell transformation with Agrobacterium tumefaciens under simulated microgravity

    Science.gov (United States)

    Sarnatska, Veresa; Gladun, Hanna; Padalko, Svetlana

    To investigate simulated microgravity (clinorotation) effect on plant cell transformation with Agrobacterium tumefaciens and crown gall formation, the culture of primary explants of potato and Jerusalem artichoke tubers was used. It is found that the efficiency of tumor formation and development in clinorotated explants are considerably reduced. When using the explants isolated from potato tubers clinorotated for 3, 5 and 19 days, drastic reduction of formation and development of crown gall tumors was observed. Conversely, the tumor number and their development increased when potato tubers were clinorotated for one day. As was estimated by us previously, cells of Jerusalem artichoke explants are the most sensitive to agrobacteria on 4-5 h of in vitro culturing and this time corresponds to the certain period of G1-stage of the cell cycle. We have also estimated that this period is characterized by the increase of binding of acridine orange by nuclear chromatin and increase in activity of RNA-polymerase I and II. Inoculation of explants with agrobacteria in this period was the most optimal for transformation and crown gall induction. We estimated that at four - hour clinorotation of explants the intensity of acridine orange binding to nuclei was considerably lower than on 4h in the control. At one-day clinorotation of potato tubers, a considerable increase in template accessibility of chromatin and in activity of RNA-polymerase I and II occurred. These results may serve as an evidence for the ability of plant dormant tissues to respond to microgravity. Another demonstration of dormant tissue response to changed gravity we obtained when investigating pathogenesis-related proteins (PR-proteins). PR-proteins were subjected to nondenaturing PAGE.and we have not found any effect of microgravity on PR-proteins of potato explants with normal or tumorous growth. We may suggest that such response derives from the common effects of two stress factors - wounding and changed

  17. Antagonism between phytohormone signalling underlies the variation in disease susceptibility of tomato plants under elevated CO2.

    Science.gov (United States)

    Zhang, Shuai; Li, Xin; Sun, Zenghui; Shao, Shujun; Hu, Lingfei; Ye, Meng; Zhou, Yanhong; Xia, Xiaojian; Yu, Jingquan; Shi, Kai

    2015-04-01

    Increasing CO2 concentrations ([CO2]) have the potential to disrupt plant-pathogen interactions in natural and agricultural ecosystems, but the research in this area has often produced conflicting results. Variations in phytohormone salicylic acid (SA) and jasmonic acid (JA) signalling could be associated with variations in the responses of pathogens to plants grown under elevated [CO2]. In this study, interactions between tomato plants and three pathogens with different infection strategies were compared. Elevated [CO2] generally favoured SA biosynthesis and signalling but repressed the JA pathway. The exposure of plants to elevated [CO2] revealed a lower incidence and severity of disease caused by tobacco mosaic virus (TMV) and by Pseudomonas syringae, whereas plant susceptibility to necrotrophic Botrytis cinerea increased. The elevated [CO2]-induced and basal resistance to TMV and P. syringae were completely abolished in plants in which the SA signalling pathway nonexpressor of pathogenesis-related genes 1 (NPR1) had been silenced or in transgenic plants defective in SA biosynthesis. In contrast, under both ambient and elevated [CO2], the susceptibility to B. cinerea highly increased in plants in which the JA signalling pathway proteinase inhibitors (PI) gene had been silenced or in a mutant affected in JA biosynthesis. However, plants affected in SA signalling remained less susceptible to this disease. These findings highlight the modulated antagonistic relationship between SA and JA that contributes to the variation in disease susceptibility under elevated [CO2]. This information will be critical for investigating how elevated CO2 may affect plant defence and the dynamics between plants and pathogens in both agricultural and natural ecosystems. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  18. Physiological and biochemical responses of thyme plants to some antioxidants

    Directory of Open Access Journals (Sweden)

    SALWA A. ORABI

    2014-11-01

    Full Text Available Orabi SA, Talaat IM, Balbaa LK. 2014. Physiological and biochemical responses of thyme plants to some antioxidants. Nusantara Bioscience 6: 118-125. Two pot experiments were conducted to investigate the effect of tryptophan, nicotinamide and α-tocopherol (each at 50 and 100 mg/L on plant growth, essential oil yield and its main constituents. All treatments significantly promoted plant height, and increased fresh and dry mass (g/plant of thyme (Thymus vulgaris L.. The treatment with 100 mg/L nicotinamide showed increasing in total potassium mainly in the first cut. Total soluble sugars, oil percentage and oil yield and protein recorded increments with tryptophan treatments. Treatment of Thymus plants with 100 mg/L nicotinamide observed the highest percentage of thymol (67.61%. Oxygenated compounds recorded the highest value with 50 mg/L α-tocopherol treatment, while the maximum non-oxygenated ones resulted from the application of 100 mg/L nicotinamide. All treatments under study significantly affected the activity of oxidoreductase enzymes (POX and PPO. Nicotinamide at the concentration of 100 mg/L recorded the highest increments in APX and GR and the lowest values in oxidoreductase enzyme activities added to the lowest values of lipid peroxidation to enhance the best protection of thyme plants.

  19. Swash Zone Response under Various Wave Regimes

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Baldock, Tom; Contestabile, Pasquale

    2011-01-01

    The modelling of swash zone (SZ) sediment transport and the resulting morphodynamics have been areas of active research over the last decade. However, many details are still to be understood, whose knowledge will be greatly advanced by the collection of high-quality data under the controlled large......-scale laboratory conditions. The research describes tests carried out in the large wave flume of the Maritime Engineering Laboratory at Catalonia University of Technology, to investigate the SZ under the storm conditions. Its main aim was to compare beach-profile responses for monochromatic waves, monochromatic...... waves plus free long waves, bi-chromatic waves and random waves. Both erosive and accretive conditions were considered. Results discussed here were derived from the analysis of only a part of the whole data set....

  20. Experience feedback system of nuclear power plant under construction

    International Nuclear Information System (INIS)

    Yu Qun; Lin Ling

    2012-01-01

    The Experience Feedback System of Hainan Nuclear Power Plant under construction, which is a typical EPC nuclear power project, is introduced in the paper. And the good practice of the system set a good example for those NPPs under construction in China. (authors)

  1. Leaf anatomy of genotypes of banana plant grown under coloured ...

    African Journals Online (AJOL)

    This study aimed to evaluate the effect of spectral light quality on different anatomical features of banana tree plantlets grown under coloured shade nets. Banana plants of five genotypes obtained from micropropagation, were grown under white, blue, red and black nets, with shade of 50%, in a completely randomized ...

  2. Antagonism between phytohormone signalling underlies the variation in disease susceptibility of tomato plants under elevated CO2

    Science.gov (United States)

    Zhang, Shuai; Li, Xin; Sun, Zenghui; Shao, Shujun; Hu, Lingfei; Ye, Meng; Zhou, Yanhong; Xia, Xiaojian; Yu, Jingquan; Shi, Kai

    2015-01-01

    Increasing CO2 concentrations ([CO2]) have the potential to disrupt plant–pathogen interactions in natural and agricultural ecosystems, but the research in this area has often produced conflicting results. Variations in phytohormone salicylic acid (SA) and jasmonic acid (JA) signalling could be associated with variations in the responses of pathogens to plants grown under elevated [CO2]. In this study, interactions between tomato plants and three pathogens with different infection strategies were compared. Elevated [CO2] generally favoured SA biosynthesis and signalling but repressed the JA pathway. The exposure of plants to elevated [CO2] revealed a lower incidence and severity of disease caused by tobacco mosaic virus (TMV) and by Pseudomonas syringae, whereas plant susceptibility to necrotrophic Botrytis cinerea increased. The elevated [CO2]-induced and basal resistance to TMV and P. syringae were completely abolished in plants in which the SA signalling pathway nonexpressor of pathogenesis-related genes 1 (NPR1) had been silenced or in transgenic plants defective in SA biosynthesis. In contrast, under both ambient and elevated [CO2], the susceptibility to B. cinerea highly increased in plants in which the JA signalling pathway proteinase inhibitors (PI) gene had been silenced or in a mutant affected in JA biosynthesis. However, plants affected in SA signalling remained less susceptible to this disease. These findings highlight the modulated antagonistic relationship between SA and JA that contributes to the variation in disease susceptibility under elevated [CO2]. This information will be critical for investigating how elevated CO2 may affect plant defence and the dynamics between plants and pathogens in both agricultural and natural ecosystems. PMID:25657213

  3. Digest: Plants adapt under attack: genotypic selection and phenotypic plasticity under herbivore pressure.

    Science.gov (United States)

    Hawkins, Nichola J

    2018-03-31

    Plant species adapt to changing environmental conditions through phenotypic plasticity and natural selection. Agrawal et al. (2018) found that dandelions responded to the presence of insect pests by producing higher levels of defensive compounds. This defensive response resulted both from phenotypic plasticity, with individual plants' defenses triggered by insect attack, and from evolution by natural selection acting on genetic variation in the plant population. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

  4. Plant responses to plant growth-promoting rhizobacteria

    NARCIS (Netherlands)

    Loon, L.C. van

    2007-01-01

    Non-pathogenic soilborne microorganisms can promote plant growth, as well as suppress diseases. Plant growth promotion is taken to result from improved nutrient acquisition or hormonal stimulation. Disease suppression can occur through microbial antagonism or induction of resistance in the plant.

  5. Growing under water - how plants cope with low CO2

    DEFF Research Database (Denmark)

    Pedersen, Ole; Hinke, Anne Bækbo; Konnerup, Dennis

    2017-01-01

    Aquatic plants are never short of water but instead they are challenged with low light and slow movement of oxygen (O₂) and carbon dioxide (CO₂). In the present paper, we focus on CO₂ limitation of underwater photosynthesis and the various strategies to overcome the limitation resulting from...... evolutionary adaptation to growth under water. Knowledge of such strategies helps you to select the right CO₂ environment and thereby maximize the chances that your favorite plants flourish....

  6. A microcosm for the breeding of plants under controlled conditions

    International Nuclear Information System (INIS)

    D'Aquino, Luigi; Maglione, Maria Grazia; Minarini, Carla; Pandolfi Giuseppe; Lanza, Bruno; Atrigna, Mauro; De Filippo, Giovanni; Giannotta, Giovanni; Pedicini Antonio; Aprano Salvatore

    2015-01-01

    In order to enhance studies of the effects of multiple stress on plant physiology laboratory scale, in collaboration with FOS Srl and Sesmat Srl and the project application for organic PON02 0 0556 3 420580 «SMARTAGS-SMARt TAGS 'was conceived, designed and built a 'microcosm for the breeding of plants under biotic and abiotic stress conditioning '. [it

  7. Biochar and Ecosystem Restoration: Plant Ecophysiological Responses

    Science.gov (United States)

    Gale, N.; Halim, M. A.; Thomas, S. C.

    2017-12-01

    Charcoal is thought to facilitate rapid plant regeneration following fires by increasing the retention and availability of nutrients and water, increasing soil pH, and by sorbing toxic and inhibitory soil compounds - responses that have recently encouraged research on "biochar," or charcoal used as a soil amendment. Interest in biochar for use in the restoration of disturbed systems is growing; however, investigations of the effects of biochar on wild plants and trees are lacking. We present results from two experiments testing the influence of biochar on the growth and physiology of pioneers. In the first study, in a glasshouse, we examined the effects of maple biochar (10 and 20 t/ha) applied to a temperate managed forest soil on the ecophysiology of 13 herbaceous old-field species. In the second study, in field trials in Bangladesh (15 x 15 m plots), we examined the effects of acacia biochar (7.5 t/ha) on the growth of regenerating dipterocarp secondary forests. In both experiments, we measured changes in nutrient availability to help explain ecophysiological responses. Biochars enhanced the performance of early successional old-field pioneers: increasing aboveground biomass (37%), photosynthesis (17%), reproductive biomass (100%), and water use efficiency (44%), but with high species-specific variation that included negative responses. In tropical forests, biochars marginally improved the growth and recruitment of canopy dipterocarps and increased the photosynthetic performance and abundance of some, but not all, of the dominant understory species. In both experiments, growth enhancement was due to pulses of PO4-and K+ supplied by biochar in the short term; while null and negative responses were the result of nitrogen immobilization for species with high photosynthetic capacities. These results suggest that by providing a pulse of P and base cations, biochar can improve the restoration of disturbed landscapes by enhancing the physiological performance of

  8. Root traits contributing to plant productivity under drought

    Directory of Open Access Journals (Sweden)

    Louise eComas

    2013-11-01

    Full Text Available Geneticists and breeders are positioned to breed plants with root traits that improve productivity under drought. However, a better understanding of root functional traits and how traits are related to whole plant strategies to increase crop productivity under different drought conditions is needed. Root traits associated with maintaining plant productivity under drought include small fine root diameters, long specific root length (SRL, and considerable root length density, especially at depths in soil with available water. In environments with late season water deficits, small xylem diameters in targeted seminal roots save soil water deep in the soil profile for use during crop maturation and result in improved yields. Capacity for deep root growth and large xylem diameters in deep roots may also improve root acquisition of water when ample water at depth is available. Xylem pit anatomy that makes xylem less ‘leaky’ and prone to cavitation warrants further exploration holding promise that such traits may improve plant productivity in water-limited environments without negatively impacting yield under adequate water conditions. Rapid resumption of root growth following soil rewetting may improve plant productivity under episodic drought. Genetic control of many of these traits through breeding appears feasible. Several recent reviews have covered methods for screening root traits but an appreciation for the complexity of root systems (e.g. functional differences between fine and coarse roots needs to be paired with these methods to successfully identify relevant traits for crop improvement. Screening of root traits at early stages in plant development can proxy traits at mature stages but verification is needed on a case by case basis that traits are linked to increased crop productivity under drought. Examples in lesquerella (Physaria and rice (Oryza show approaches to phenotyping of root traits and current understanding of root trait

  9. Root traits contributing to plant productivity under drought.

    Science.gov (United States)

    Comas, Louise H; Becker, Steven R; Cruz, Von Mark V; Byrne, Patrick F; Dierig, David A

    2013-11-05

    Geneticists and breeders are positioned to breed plants with root traits that improve productivity under drought. However, a better understanding of root functional traits and how traits are related to whole plant strategies to increase crop productivity under different drought conditions is needed. Root traits associated with maintaining plant productivity under drought include small fine root diameters, long specific root length, and considerable root length density, especially at depths in soil with available water. In environments with late season water deficits, small xylem diameters in targeted seminal roots save soil water deep in the soil profile for use during crop maturation and result in improved yields. Capacity for deep root growth and large xylem diameters in deep roots may also improve root acquisition of water when ample water at depth is available. Xylem pit anatomy that makes xylem less "leaky" and prone to cavitation warrants further exploration holding promise that such traits may improve plant productivity in water-limited environments without negatively impacting yield under adequate water conditions. Rapid resumption of root growth following soil rewetting may improve plant productivity under episodic drought. Genetic control of many of these traits through breeding appears feasible. Several recent reviews have covered methods for screening root traits but an appreciation for the complexity of root systems (e.g., functional differences between fine and coarse roots) needs to be paired with these methods to successfully identify relevant traits for crop improvement. Screening of root traits at early stages in plant development can proxy traits at mature stages but verification is needed on a case by case basis that traits are linked to increased crop productivity under drought. Examples in lesquerella (Physaria) and rice (Oryza) show approaches to phenotyping of root traits and current understanding of root trait genetics for breeding.

  10. Plant neighbour identity matters to belowground interactions under controlled conditions.

    Science.gov (United States)

    Armas, Cristina; Pugnaire, Francisco Ignacio

    2011-01-01

    Root competition is an almost ubiquitous feature of plant communities with profound effects on their structure and composition. Far beyond the traditional view that plants interact mainly through resource depletion (exploitation competition), roots are known to be able to interact with their environment using a large variety of mechanisms that may inhibit or enhance access of other roots to the resource or affect plant growth (contest interactions). However, an extensive analysis on how these contest root interactions may affect species interaction abilities is almost lacking. In a common garden experiment with ten perennial plant species we forced pairs of plants of the same or different species to overlap their roots and analyzed how belowground contest interactions affected plant performance, biomass allocation patterns, and competitive abilities under abundant resource supply. Our results showed that net interaction outcome ranged from negative to positive, affecting total plant mass and allocation patterns. A species could be a strong competitor against one species, weaker against another one, and even facilitator to a third species. This leads to sets of species where competitive hierarchies may be clear but also to groups where such rankings are not, suggesting that intransitive root interactions may be crucial for species coexistence. The outcome of belowground contest interactions is strongly dependent on neighbours' identity. In natural plant communities this conditional outcome may hypothetically help species to interact in non-hierarchical and intransitive networks, which in turn might promote coexistence.

  11. Plant neighbour identity matters to belowground interactions under controlled conditions.

    Directory of Open Access Journals (Sweden)

    Cristina Armas

    Full Text Available BACKGROUND: Root competition is an almost ubiquitous feature of plant communities with profound effects on their structure and composition. Far beyond the traditional view that plants interact mainly through resource depletion (exploitation competition, roots are known to be able to interact with their environment using a large variety of mechanisms that may inhibit or enhance access of other roots to the resource or affect plant growth (contest interactions. However, an extensive analysis on how these contest root interactions may affect species interaction abilities is almost lacking. METHODOLOGY/PRINCIPAL FINDINGS: In a common garden experiment with ten perennial plant species we forced pairs of plants of the same or different species to overlap their roots and analyzed how belowground contest interactions affected plant performance, biomass allocation patterns, and competitive abilities under abundant resource supply. Our results showed that net interaction outcome ranged from negative to positive, affecting total plant mass and allocation patterns. A species could be a strong competitor against one species, weaker against another one, and even facilitator to a third species. This leads to sets of species where competitive hierarchies may be clear but also to groups where such rankings are not, suggesting that intransitive root interactions may be crucial for species coexistence. CONCLUSIONS/SIGNIFICANCE: The outcome of belowground contest interactions is strongly dependent on neighbours' identity. In natural plant communities this conditional outcome may hypothetically help species to interact in non-hierarchical and intransitive networks, which in turn might promote coexistence.

  12. When do plants modify fluvial processes? Plant-hydraulic interactions under variable flow and sediment supply rates

    Science.gov (United States)

    Manners, Rebecca B.; Wilcox, Andrew C.; Kui, Li; Lightbody, Anne F.; Stella, John C.; Sklar, Leonard S.

    2015-02-01

    Flow and sediment regimes shape alluvial river channels; yet the influence of these abiotic drivers can be strongly mediated by biotic factors such as the size and density of riparian vegetation. We present results from an experiment designed to identify when plants control fluvial processes and to investigate the sensitivity of fluvial processes to changes in plant characteristics versus changes in flow rate or sediment supply. Live seedlings of two species with distinct morphologies, tamarisk (Tamarix spp.) and cottonwood (Populus fremontii), were placed in different configurations in a mobile sand-bed flume. We measured the hydraulic and sediment flux responses of the channel at different flow rates and sediment supply conditions representing equilibrium (sediment supply = transport rate) and deficit (sediment supply plant species and configuration. Species-specific traits controlled the hydraulic response: compared to cottonwood, which has a more tree-like morphology, the shrubby morphology of tamarisk resulted in less pronation and greater reductions in near-bed velocities, Reynolds stress, and sediment flux rates. Under sediment-deficit conditions, on the other hand, abiotic factors dampened the effect of variations in plant characteristics on the hydraulic response. We identified scenarios for which the highest stem-density patch, independent of abiotic factors, dominated the fluvial response. These results provide insight into how and when plants influence fluvial processes in natural systems.

  13. Impeded Carbohydrate Metabolism in Rice Plants under Submergence Stress

    Directory of Open Access Journals (Sweden)

    Malay Kumar ADAK

    2011-06-01

    Full Text Available The detrimental effects of submergence on physiological performances of some rice varieties with special references to carbohydrate metabolisms and their allied enzymes during post-flowering stages have been documented and clarified in the present investigation. It was found that photosynthetic rate and concomitant translocation of sugars into the panicles were both related to the yield. The detrimental effects of the complete submergence were recorded in generation of sucrose, starch, sucrose phosphate synthase and phosphorylase activity in the developing panicles of the plants as compared to those under normal or control (i.e. non-submerged condition. The accumulation of starch was significantly lower in plants under submergence and that was correlated with ADP-glucose pyrophosphorylase activity. Photosynthetic rate was most affected under submergence in varying days of post-flowering and was also related to the down regulation of Ribulose bisphosphate carboxylase activity. However, under normal or control condition, there recorded a steady maintenance of photosynthetic rate at the post-flowering stages and significantly higher values of Ribulose bisphosphate carboxylase activity. Still, photosynthetic rate of the plants under both control and submerged conditions had hardly any significant correlation with sugar accumulation and other enzymes of carbohydrate metabolism like invertase with grain yield. Finally, plants under submergence suffered significant loss of yield by poor grain filling which was related to impeded carbohydrate metabolism in the tissues. It is evident that loss of yield under submergence is attributed both by lower sink size or sink capacity (number of panicles, in this case as well as subdued carbohydrate metabolism in plants and its subsequent partitioning into the grains.

  14. Microclimate moderates plant responses to macroclimate warming.

    Science.gov (United States)

    De Frenne, Pieter; Rodríguez-Sánchez, Francisco; Coomes, David Anthony; Baeten, Lander; Verstraeten, Gorik; Vellend, Mark; Bernhardt-Römermann, Markus; Brown, Carissa D; Brunet, Jörg; Cornelis, Johnny; Decocq, Guillaume M; Dierschke, Hartmut; Eriksson, Ove; Gilliam, Frank S; Hédl, Radim; Heinken, Thilo; Hermy, Martin; Hommel, Patrick; Jenkins, Michael A; Kelly, Daniel L; Kirby, Keith J; Mitchell, Fraser J G; Naaf, Tobias; Newman, Miles; Peterken, George; Petrík, Petr; Schultz, Jan; Sonnier, Grégory; Van Calster, Hans; Waller, Donald M; Walther, Gian-Reto; White, Peter S; Woods, Kerry D; Wulf, Monika; Graae, Bente Jessen; Verheyen, Kris

    2013-11-12

    Recent global warming is acting across marine, freshwater, and terrestrial ecosystems to favor species adapted to warmer conditions and/or reduce the abundance of cold-adapted organisms (i.e., "thermophilization" of communities). Lack of community responses to increased temperature, however, has also been reported for several taxa and regions, suggesting that "climatic lags" may be frequent. Here we show that microclimatic effects brought about by forest canopy closure can buffer biotic responses to macroclimate warming, thus explaining an apparent climatic lag. Using data from 1,409 vegetation plots in European and North American temperate forests, each surveyed at least twice over an interval of 12-67 y, we document significant thermophilization of ground-layer plant communities. These changes reflect concurrent declines in species adapted to cooler conditions and increases in species adapted to warmer conditions. However, thermophilization, particularly the increase of warm-adapted species, is attenuated in forests whose canopies have become denser, probably reflecting cooler growing-season ground temperatures via increased shading. As standing stocks of trees have increased in many temperate forests in recent decades, local microclimatic effects may commonly be moderating the impacts of macroclimate warming on forest understories. Conversely, increases in harvesting woody biomass--e.g., for bioenergy--may open forest canopies and accelerate thermophilization of temperate forest biodiversity.

  15. Utilization of (15)NO3 (-) by nodulated soybean plants under conditions of root hypoxia.

    Science.gov (United States)

    Nunes Menolli Lanza, Luciana; Ferreira Lanza, Daniel Carlos; Sodek, Ladaslav

    2014-07-01

    Waterlogging of soils is common in nature. The low availability of oxygen under these conditions leads to hypoxia of the root system impairing the development and productivity of the plant. The presence of nitrate under flooding conditions is regarded as being beneficial towards tolerance to this stress. However, it is not known how nodulated soybean plants, cultivated in the absence of nitrate and therefore not metabolically adapted to this compound, would respond to nitrate under root hypoxia in comparison with non-nodulated plants grown on nitrate. A study was conducted with (15)N labelled nitrate supplied on waterlogging for a period of 48 h using both nodulated and non-nodulated plants of different physiological ages. Enrichment of N was found in roots and leaves with incorporation of the isotope in amino acids, although to a much smaller degree under hypoxia than normoxia. This demonstrates that nitrate is taken up under hypoxic conditions and assimilated into amino acids, although to a much lesser extent than for normoxia. The similar response obtained with nodulated and non-nodulated plants indicates the rapid metabolic adaptation of nodulated plants to the presence of nitrate under hypoxia. Enrichment of N in nodules was very much weaker with a distinct enrichment pattern of amino acids (especially asparagine) suggesting that labelling arose from a tissue source external to the nodule rather than through assimilation in the nodule itself.

  16. Urban plant physiology: adaptation-mitigation strategies under permanent stress.

    Science.gov (United States)

    Calfapietra, Carlo; Peñuelas, Josep; Niinemets, Ülo

    2015-02-01

    Urban environments that are stressful for plant function and growth will become increasingly widespread in future. In this opinion article, we define the concept of 'urban plant physiology', which focuses on plant responses and long term adaptations to urban conditions and on the capacity of urban vegetation to mitigate environmental hazards in urbanized settings such as air and soil pollution. Use of appropriate control treatments would allow for studies in urban environments to be comparable to expensive manipulative experiments. In this opinion article, we propose to couple two approaches, based either on environmental gradients or manipulated gradients, to develop the concept of urban plant physiology for assessing how single or multiple environmental factors affect the key environmental services provided by urban forests. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Catalase activity of cassava ( Manihot esculenta ) plant under ...

    African Journals Online (AJOL)

    African cassava mosaic virus has caused an immersed low yield of the cassava crop. The virus impacts stress on the cellular metabolism of the plant producing a lot of reactive oxygen species and increases the expression of the antioxidant enzymes. The activity of catalase as a response to oxidative stress was investigated ...

  18. Growth of Planted Slash Pine Under Several Thinning Regimes

    Science.gov (United States)

    W.F. Mann; Hans G. Enghardt

    1972-01-01

    Three intensities of thinning, each started at 10, 13, and 16 years, were applied to slash pine planted on a highly productive, cutover site in central Louisiana. Over a 9-year period, early and heavy thinnings increased diameter growth but reduced volume growth. The longer initial thinnings were deferred, the slower was the response in diameter growth. Growth on...

  19. Variable hydraulic resistances and their impact on plant drought response modelling.

    Science.gov (United States)

    Baert, Annelies; De Schepper, Veerle; Steppe, Kathy

    2015-04-01

    Plant drought responses are still not fully understood. Improved knowledge on drought responses is, however, crucial to better predict their impact on individual plant and ecosystem functioning. Mechanistic models in combination with plant measurements are promising for obtaining information on plant water status and can assist us in understanding the effect of limiting soil water availability and drought stress. While existing models are reliable under sufficient soil water availability, they generally fail under dry conditions as not all appropriate mechanisms seem yet to have been implemented. We therefore aimed at identifying mechanisms underlying plant drought responses, and in particular investigated the behaviour of hydraulic resistances encountered in the soil and xylem for grapevine (Vitis vinifera L.) and oak (Quercus robur L.). A variable hydraulic soil-to-stem resistance was necessary to describe plant drought responses. In addition, implementation of a variable soil-to-stem hydraulic resistance enabled us to generate an in situ soil-to-stem vulnerability curve, which might be an alternative to the conventionally used vulnerability curves. Furthermore, a daily recalibration of the model revealed a drought-induced increase in radial hydraulic resistance between xylem and elastic living tissues. Accurate information on plant hydraulic resistances and simulation of plant drought responses can foster important discussions regarding the functioning of plants and ecosystems during droughts. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Plant molecular stress responses face climate change. Trends in Plants

    NARCIS (Netherlands)

    Ahuja, I.; Vos, de R.C.H.; Bones, A.M.; Hall, R.D.

    2010-01-01

    Environmental stress factors such as drought, elevated temperature, salinity and rising CO2 affect plant growth and pose a growing threat to sustainable agriculture. This has become a hot issue due to concerns about the effects of climate change on plant resources, biodiversity and global food

  1. Plant - microbe interactions under Global Change: the microbial perspective

    Science.gov (United States)

    Richter, Andreas

    2017-04-01

    There is ample evidence that both microorganisms and plants will respond to Global Changes, such as enhanced temperatures, increased nitrogen deposition and atmospheric CO2 concentrations, or biodiversity loss. Plant and microbial activities are linked, amongst other factors, by belowground carbon allocation and aboveground nutrient allocation, which may be altered under Global Changes to different extents. The effect of Global Changes on the interaction of plants and microbes is therefore often difficult to predict. In my talk, I will look at plant-microbe interactions from a microbial perspective. I will ask the question what the direct and indirect (plant-mediated) effects of Global Changes are on microbial activities in soil and what this in turn means for plants and for ecosystem-scale fluxes. I will present results from an in-situ drought experiment, from a long-term soil warming experiment and from a plant diversity experiment, where we investigated microbial growth and turnover, carbon and nutrient use efficiency and gross nutrient transformation rates.

  2. 47 CFR 32.2003 - Telecommunications plant under construction.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Telecommunications plant under construction. 32.2003 Section 32.2003 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES UNIFORM SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet...

  3. Plant responses to variable timing of aboveground clipping and belowground herbivory depend on plant age

    NARCIS (Netherlands)

    Wang, Minggang; Bezemer, T. Martijn; van der Putten, W.H.; Brinkman, Pella; Biere, Arjen

    2017-01-01

    Aims Plants use different types of responses such as tolerance and induced defense to mitigate the effects of herbivores. The direction and magnitude of both these plant responses can vary with plant age. However, most studies have focused on aboveground herbivory, whereas important feeding occurs

  4. Plant responses to variable timing of aboveground clipping and belowground herbivory depend on plant age

    NARCIS (Netherlands)

    Wang, Minggang; Bezemer, T.M.; Putten, Van Der Wim H.; Brinkman, E.P.; Biere, Arjen

    2017-01-01

    Aims
    Plants use different types of responses such as tolerance and
    induced defense to mitigate the effects of herbivores. The direction
    and magnitude of both these plant responses can vary with
    plant age. However, most studies have focused on aboveground
    herbivory, whereas

  5. Plant-insect interactions under bacterial influence: ecological implications and underlying mechanisms.

    Science.gov (United States)

    Sugio, Akiko; Dubreuil, Géraldine; Giron, David; Simon, Jean-Christophe

    2015-02-01

    Plants and insects have been co-existing for more than 400 million years, leading to intimate and complex relationships. Throughout their own evolutionary history, plants and insects have also established intricate and very diverse relationships with microbial associates. Studies in recent years have revealed plant- or insect-associated microbes to be instrumental in plant-insect interactions, with important implications for plant defences and plant utilization by insects. Microbial communities associated with plants are rich in diversity, and their structure greatly differs between below- and above-ground levels. Microbial communities associated with insect herbivores generally present a lower diversity and can reside in different body parts of their hosts including bacteriocytes, haemolymph, gut, and salivary glands. Acquisition of microbial communities by vertical or horizontal transmission and possible genetic exchanges through lateral transfer could strongly impact on the host insect or plant fitness by conferring adaptations to new habitats. Recent developments in sequencing technologies and molecular tools have dramatically enhanced opportunities to characterize the microbial diversity associated with plants and insects and have unveiled some of the mechanisms by which symbionts modulate plant-insect interactions. Here, we focus on the diversity and ecological consequences of bacterial communities associated with plants and herbivorous insects. We also highlight the known mechanisms by which these microbes interfere with plant-insect interactions. Revealing such mechanisms in model systems under controlled environments but also in more natural ecological settings will help us to understand the evolution of complex multitrophic interactions in which plants, herbivorous insects, and micro-organisms are inserted. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions

  6. Plant responses to environmental stresses-from gene to biotechnology.

    Science.gov (United States)

    Ahanger, Mohammad Abass; Akram, Nudrat Aisha; Ashraf, Muhammad; Alyemeni, Mohammed Nasser; Wijaya, Leonard; Ahmad, Parvaiz

    2017-07-01

    Increasing global population, urbanization and industrialization are increasing the rate of conversion of arable land into wasteland. Supplying food to an ever-increasing population is one of the biggest challenges that agriculturalists and plant scientists are currently confronting. Environmental stresses make this situation even graver. Despite the induction of several tolerance mechanisms, sensitive plants often fail to survive under environmental extremes. New technological approaches are imperative. Conventional breeding methods have a limited potential to improve plant genomes against environmental stress. Recently, genetic engineering has contributed enormously to the development of genetically modified varieties of different crops such as cotton, maize, rice, canola and soybean. The identification of stress-responsive genes and their subsequent introgression or overexpression within sensitive crop species are now being widely carried out by plant scientists. Engineering of important tolerance pathways, like antioxidant enzymes, osmolyte accumulation, membrane-localized transporters for efficient compartmentation of deleterious ions and accumulation of essential elements and resistance against pests or pathogens is also an area that has been intensively researched. In this review, the role of biotechnology and its successes, prospects and challenges in developing stress-tolerant crop cultivars are discussed.

  7. A Latex Metabolite Benefits Plant Fitness under Root Herbivore Attack

    Science.gov (United States)

    Huber, Meret; Epping, Janina; Schulze Gronover, Christian; Fricke, Julia; Aziz, Zohra; Brillatz, Théo; Swyers, Michael; Köllner, Tobias G.; Vogel, Heiko; Hammerbacher, Almuth; Triebwasser-Freese, Daniella; Robert, Christelle A. M.; Verhoeven, Koen; Preite, Veronica; Gershenzon, Jonathan; Erb, Matthias

    2016-01-01

    Plants produce large amounts of secondary metabolites in their shoots and roots and store them in specialized secretory structures. Although secondary metabolites and their secretory structures are commonly assumed to have a defensive function, evidence that they benefit plant fitness under herbivore attack is scarce, especially below ground. Here, we tested whether latex secondary metabolites produced by the common dandelion (Taraxacum officinale agg.) decrease the performance of its major native insect root herbivore, the larvae of the common cockchafer (Melolontha melolontha), and benefit plant vegetative and reproductive fitness under M. melolontha attack. Across 17 T. officinale genotypes screened by gas and liquid chromatography, latex concentrations of the sesquiterpene lactone taraxinic acid β-D-glucopyranosyl ester (TA-G) were negatively associated with M. melolontha larval growth. Adding purified TA-G to artificial diet at ecologically relevant concentrations reduced larval feeding. Silencing the germacrene A synthase ToGAS1, an enzyme that was identified to catalyze the first committed step of TA-G biosynthesis, resulted in a 90% reduction of TA-G levels and a pronounced increase in M. melolontha feeding. Transgenic, TA-G-deficient lines were preferred by M. melolontha and suffered three times more root biomass reduction than control lines. In a common garden experiment involving over 2,000 T. officinale individuals belonging to 17 different genotypes, high TA-G concentrations were associated with the maintenance of high vegetative and reproductive fitness under M. melolontha attack. Taken together, our study demonstrates that a latex secondary metabolite benefits plants under herbivore attack, a result that provides a mechanistic framework for root herbivore driven natural selection and evolution of plant defenses below ground. PMID:26731567

  8. A Latex Metabolite Benefits Plant Fitness under Root Herbivore Attack.

    Directory of Open Access Journals (Sweden)

    Meret Huber

    2016-01-01

    Full Text Available Plants produce large amounts of secondary metabolites in their shoots and roots and store them in specialized secretory structures. Although secondary metabolites and their secretory structures are commonly assumed to have a defensive function, evidence that they benefit plant fitness under herbivore attack is scarce, especially below ground. Here, we tested whether latex secondary metabolites produced by the common dandelion (Taraxacum officinale agg. decrease the performance of its major native insect root herbivore, the larvae of the common cockchafer (Melolontha melolontha, and benefit plant vegetative and reproductive fitness under M. melolontha attack. Across 17 T. officinale genotypes screened by gas and liquid chromatography, latex concentrations of the sesquiterpene lactone taraxinic acid β-D-glucopyranosyl ester (TA-G were negatively associated with M. melolontha larval growth. Adding purified TA-G to artificial diet at ecologically relevant concentrations reduced larval feeding. Silencing the germacrene A synthase ToGAS1, an enzyme that was identified to catalyze the first committed step of TA-G biosynthesis, resulted in a 90% reduction of TA-G levels and a pronounced increase in M. melolontha feeding. Transgenic, TA-G-deficient lines were preferred by M. melolontha and suffered three times more root biomass reduction than control lines. In a common garden experiment involving over 2,000 T. officinale individuals belonging to 17 different genotypes, high TA-G concentrations were associated with the maintenance of high vegetative and reproductive fitness under M. melolontha attack. Taken together, our study demonstrates that a latex secondary metabolite benefits plants under herbivore attack, a result that provides a mechanistic framework for root herbivore driven natural selection and evolution of plant defenses below ground.

  9. A Latex Metabolite Benefits Plant Fitness under Root Herbivore Attack.

    Science.gov (United States)

    Huber, Meret; Epping, Janina; Schulze Gronover, Christian; Fricke, Julia; Aziz, Zohra; Brillatz, Théo; Swyers, Michael; Köllner, Tobias G; Vogel, Heiko; Hammerbacher, Almuth; Triebwasser-Freese, Daniella; Robert, Christelle A M; Verhoeven, Koen; Preite, Veronica; Gershenzon, Jonathan; Erb, Matthias

    2016-01-01

    Plants produce large amounts of secondary metabolites in their shoots and roots and store them in specialized secretory structures. Although secondary metabolites and their secretory structures are commonly assumed to have a defensive function, evidence that they benefit plant fitness under herbivore attack is scarce, especially below ground. Here, we tested whether latex secondary metabolites produced by the common dandelion (Taraxacum officinale agg.) decrease the performance of its major native insect root herbivore, the larvae of the common cockchafer (Melolontha melolontha), and benefit plant vegetative and reproductive fitness under M. melolontha attack. Across 17 T. officinale genotypes screened by gas and liquid chromatography, latex concentrations of the sesquiterpene lactone taraxinic acid β-D-glucopyranosyl ester (TA-G) were negatively associated with M. melolontha larval growth. Adding purified TA-G to artificial diet at ecologically relevant concentrations reduced larval feeding. Silencing the germacrene A synthase ToGAS1, an enzyme that was identified to catalyze the first committed step of TA-G biosynthesis, resulted in a 90% reduction of TA-G levels and a pronounced increase in M. melolontha feeding. Transgenic, TA-G-deficient lines were preferred by M. melolontha and suffered three times more root biomass reduction than control lines. In a common garden experiment involving over 2,000 T. officinale individuals belonging to 17 different genotypes, high TA-G concentrations were associated with the maintenance of high vegetative and reproductive fitness under M. melolontha attack. Taken together, our study demonstrates that a latex secondary metabolite benefits plants under herbivore attack, a result that provides a mechanistic framework for root herbivore driven natural selection and evolution of plant defenses below ground.

  10. Protection of warehouses and plants under capacity constraint

    International Nuclear Information System (INIS)

    Bricha, Naji; Nourelfath, Mustapha

    2015-01-01

    While warehouses may be subjected to less protection effort than plants, their unavailability may have substantial impact on the supply chain performance. This paper presents a method for protection of plants and warehouses against intentional attacks in the context of the capacitated plant and warehouses location and capacity acquisition problem. A non-cooperative two-period game is developed to find the equilibrium solution and the optimal defender strategy under capacity constraints. The defender invests in the first period to minimize the expected damage and the attacker moves in the second period to maximize the expected damage. Extra-capacity of neighboring functional plants and warehouses is used after attacks, to satisfy all customers demand and to avoid the backorders. The contest success function is used to evaluate success probability of an attack of plants and warehouses. A numerical example is presented to illustrate an application of the model. The defender strategy obtained by our model is compared to the case where warehouses are subjected to less protection effort than the plants. This comparison allows us to measure how much our method is better, and illustrates the effect of direct investments in protection and indirect protection by warehouse extra-capacities to reduce the expected damage. - Highlights: • Protection of warehouses and plants against intentional attacks. • Capacitated plant and warehouse location and capacity acquisition problem. • A non-cooperative two-period game between the defender and the attacker. • A method to evaluate the utilities and determine the optimal defender strategy. • Using warehouse extra-capacities to reduce the expected damage

  11. Plant natriuretic peptides are apoplastic and paracrine stress response molecules

    KAUST Repository

    Wang, Yuhua

    2011-04-07

    Higher plants contain biologically active proteins that are recognized by antibodies against human atrial natriuretic peptide (ANP). We identified and isolated two Arabidopsis thaliana immunoreactive plant natriuretic peptide (PNP)-encoding genes, AtPNP-A and AtPNP-B, which are distantly related members of the expansin superfamily and have a role in the regulation of homeostasis in abiotic and biotic stresses, and have shown that AtPNP-A modulates the effects of ABA on stomata. Arabidopsis PNP (PNP-A) is mainly expressed in leaf mesophyll cells, and in protoplast assays we demonstrate that it is secreted using AtPNP-A:green fluorescent protein (GFP) reporter constructs and flow cytometry. Transient reporter assays provide evidence that AtPNP-A expression is enhanced by heat, osmotica and salt, and that AtPNP-A itself can enhance its own expression, thereby generating a response signature diagnostic for paracrine action and potentially also autocrine effects. Expression of native AtPNP-A is enhanced by osmotica and transiently by salt. Although AtPNP-A expression is induced by salt and osmotica, ABA does not significantly modulate AtPNP-A levels nor does recombinant AtPNP-A affect reporter expression of the ABA-responsive RD29A gene. Together, these results provide experimental evidence that AtPNP-A is stress responsive, secreted into the apoplastic space and can enhance its own expression. Furthermore, our findings support the idea that AtPNP-A, together with ABA, is an important component in complex plant stress responses and that, much like in animals, peptide signaling molecules can create diverse and modular signals essential for growth, development and defense under rapidly changing environmental conditions. © 2011 The Author.

  12. Effect of mycorrhizas application on plant growth and nutrient uptake in cucumber production under field conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ortas, I.

    2010-07-01

    Mycorrhizas application in horticultural production in the Eastern Mediterranean region of Turkey has been studied under field conditions for several years. The effects of different arbuscular mycorrhizal fungi (AMF) have been evaluated under field conditions for cucumber production. The parameters measured were seedling survival, plant growth and yield, and root colonization. In 1998 and 1999, Glomus mosseae and Glomus etunicatum inoculated cucumber seedlings were treated with and without P (100 kg P2O5 ha-1) application. A second experiment was set up to evaluate the response of cucumber to the inoculation with a consortia of indigenous mycorrhizae, G. mosseae, G. etunicatum, Glomus clarum, Glomus caledonium and a mixture of these four species. Inoculated and control non inoculated cucumber seedlings were established under field conditions in 1998, 2001, 2002 and 2004. Seedling quality, seedling survival under field conditions and yield response to mycorrhiza were tested. Fruits were harvested periodically; at blossom, plant leaves and root samples were taken for nutrient content and mycorrhizal colonization analysis respectively. The field experiment results showed that mycorrhiza inoculation significantly increased cucumber seedling survival, fruit yield, P and Zn shoot concentrations. Indigenous mycorrhiza inoculum was successful in colonizing plant roots and resulted in better plant growth and yield. The relative effectiveness of each of the inocula tested was not consistent in the different experiments, although inoculated plants always grew better than control no inoculated. The most relevant result for growers was the increased survival of seedlings. (Author) 20 refs.

  13. Physiological and molecular alterations in plants exposed to high [CO2] under phosphorus stress.

    Science.gov (United States)

    Pandey, Renu; Zinta, Gaurav; AbdElgawad, Hamada; Ahmad, Altaf; Jain, Vanita; Janssens, Ivan A

    2015-01-01

    Atmospheric [CO2] has increased substantially in recent decades and will continue to do so, whereas the availability of phosphorus (P) is limited and unlikely to increase in the future. P is a non-renewable resource, and it is essential to every form of life. P is a key plant nutrient controlling the responsiveness of photosynthesis to [CO2]. Increases in [CO2] typically results in increased biomass through stimulation of net photosynthesis, and hence enhance the demand for P uptake. However, most soils contain low concentrations of available P. Therefore, low P is one of the major growth-limiting factors for plants in many agricultural and natural ecosystems. The adaptive responses of plants to [CO2] and P availability encompass alterations at morphological, physiological, biochemical and molecular levels. In general low P reduces growth, whereas high [CO2] enhances it particularly in C3 plants. Photosynthetic capacity is often enhanced under high [CO2] with sufficient P supply through modulation of enzyme activities involved in carbon fixation such as ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). However, high [CO2] with low P availability results in enhanced dry matter partitioning towards roots. Alterations in below-ground processes including root morphology, exudation and mycorrhizal association are influenced by [CO2] and P availability. Under high P availability, elevated [CO2] improves the uptake of P from soil. In contrast, under low P availability, high [CO2] mainly improves the efficiency with which plants produce biomass per unit P. At molecular level, the spatio-temporal regulation of genes involved in plant adaptation to low P and high [CO2] has been studied individually in various plant species. Genome-wide expression profiling of high [CO2] grown plants revealed hormonal regulation of biomass accumulation through complex transcriptional networks. Similarly, differential transcriptional regulatory networks are involved in P

  14. Insect herbivore- associated organisms affect plant responses to herbivory

    NARCIS (Netherlands)

    Zhu, F.; Poelman, E.H.; Dicke, M.

    2014-01-01

    In nature, plants interact with many organisms and need to integrate their responses to these diverse community members. Knowledge on plant-insect relationships has accumulated rapidly during the last decades. Yet most studies on direct or indirect defences of plants against herbivory have treated

  15. Agroecology: Implications for plant response to climate change

    Science.gov (United States)

    Agricultural ecosystems (agroecosystems) represent the balance between the physiological responses of plants and plant canopies and the energy exchanges. Rising temperature and increasing CO2 coupled with an increase in variability of precipitation will create a complex set of interactions on plant ...

  16. Plant transcriptomics and responses to environmental stress: an ...

    Indian Academy of Sciences (India)

    Different stresses include nutrient deficiency, pathogen attack, exposure to toxic chemicals etc. Transcriptomic studies have been mainly applied to only a few plant species including the model plant, Arabidopsis thaliana. These studies have provided valuable insights into the genetic networks of plant stress responses.

  17. Agrobacterium tumefaciens responses to plant-derived signaling molecules

    Directory of Open Access Journals (Sweden)

    Sujatha eSubramoni

    2014-07-01

    Full Text Available As a special phytopathogen, Agrobacterium tumefaciens infects a wide range of plant hosts and causes plant tumors also known as crown galls. The complexity of Agrobacterium-plant interaction has been studied for several decades. Agrobacterium pathogenicity is largely attributed to its evolved capabilities of precise recognition and response to plant-derived chemical signals. Agrobacterium perceives plant-derived signals to activate its virulence genes, which are responsible for transferring and integrating its T-DNA (Transferred DNA from its Tumour-inducing (Ti plasmid into the plant nucleus. The expression of T-DNA in plant hosts leads to the production of a large amount of indole-3-acetic acid (IAA, cytokinin (CK and opines. IAA and CK stimulate plant growth, resulting in tumor formation. Agrobacterium utilizes opines as nutrient sources as well as signals in order to activate its quorum sensing (QS to further promote virulence and opine metabolism. Intriguingly, Agrobacterium also recognizes plant-derived signals including -amino butyric acid (GABA and salicylic acid (SA to activate quorum quenching that reduces the level of QS signals, thereby avoiding the elicitation of plant defense and preserving energy. In addition, Agrobacterium hijacks plant-derived signals including SA, IAA, and ethylene (ET to down-regulate its virulence genes located on the Ti plasmid. Moreover, certain metabolites from corn (Zea mays also inhibit the expression of Agrobacterium virulence genes. Here we outline the responses of Agrobacterium to major plant-derived signals that impact Agrobacterium-plant interactions.

  18. Agrobacterium tumefaciens responses to plant-derived signaling molecules

    Science.gov (United States)

    Subramoni, Sujatha; Nathoo, Naeem; Klimov, Eugene; Yuan, Ze-Chun

    2014-01-01

    As a special phytopathogen, Agrobacterium tumefaciens infects a wide range of plant hosts and causes plant tumors also known as crown galls. The complexity of Agrobacterium–plant interaction has been studied for several decades. Agrobacterium pathogenicity is largely attributed to its evolved capabilities of precise recognition and response to plant-derived chemical signals. Agrobacterium perceives plant-derived signals to activate its virulence genes, which are responsible for transferring and integrating its Transferred DNA (T-DNA) from its Tumor-inducing (Ti) plasmid into the plant nucleus. The expression of T-DNA in plant hosts leads to the production of a large amount of indole-3-acetic acid (IAA), cytokinin (CK), and opines. IAA and CK stimulate plant growth, resulting in tumor formation. Agrobacterium utilizes opines as nutrient sources as well as signals in order to activate its quorum sensing (QS) to further promote virulence and opine metabolism. Intriguingly, Agrobacterium also recognizes plant-derived signals including γ-amino butyric acid and salicylic acid (SA) to activate quorum quenching that reduces the level of QS signals, thereby avoiding the elicitation of plant defense and preserving energy. In addition, Agrobacterium hijacks plant-derived signals including SA, IAA, and ethylene to down-regulate its virulence genes located on the Ti plasmid. Moreover, certain metabolites from corn (Zea mays) also inhibit the expression of Agrobacterium virulence genes. Here we outline the responses of Agrobacterium to major plant-derived signals that impact Agrobacterium–plant interactions. PMID:25071805

  19. Evolutionary responses of native plant species to invasive plants: a review.

    Science.gov (United States)

    Oduor, Ayub M O

    2013-12-01

    Strong competition from invasive plant species often leads to declines in abundances and may, in certain cases, cause localized extinctions of native plant species. Nevertheless, studies have shown that certain populations of native plant species can co-exist with invasive plant species,suggesting the possibility of adaptive evolutionary responses of those populations to the invasive plants. Empirical inference of evolutionary responses of the native plant species to invasive plants has involved experiments comparing two conspecific groups of native plants for differences in expression of growth/reproductive traits: populations that have experienced competition from the invasive plant species (i.e. experienced natives) versus populations with no known history of interactions with the invasive plant species (i.e. naıve natives). Here, I employ a meta-analysis to obtain a general pattern of inferred evolutionary responses of native plant species from 53 such studies. In general, the experienced natives had significantly higher growth/reproductive performances than naıve natives, when grown with or without competition from invasive plants.While the current results indicate that certain populations of native plant species could potentially adapt evolutionarily to invasive plant species, the ecological and evolutionary mechanisms that probably underlie such evolutionary responses remain unexplored and should be the focus of future studies.

  20. 42 CFR 408.86 - Responsibilities under group billing arrangement.

    Science.gov (United States)

    2010-10-01

    ... Payment § 408.86 Responsibilities under group billing arrangement. (a) Enrollee responsibilities. (1) The enrollee is still responsible for premium payments; the group payer simply acts as his agent. If the agent... 42 Public Health 2 2010-10-01 2010-10-01 false Responsibilities under group billing arrangement...

  1. Emergency response training with the BNL plant analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, H.S.; Guppy, J.G.; Mallen, A.N.; Wulff, W.

    1987-01-01

    Presented is the experience in the use of the BNL Plant Analyzer for NRC emergency response training to simulated accidents in a BWR. The unique features of the BNL Plant Analyzer that are important for the emergency response training are summarized. A closed-loop simulation of all the key systems of a power plant in question was found essential to the realism of the emergency drills conducted at NRC. The faster than real-time simulation speeds afforded by the BNL Plant Analyzer have demonstrated its usefulness for the timely conduct of the emergency response training.

  2. Physiological response of soybean genotypes to plant density

    NARCIS (Netherlands)

    Gan, Y; Stulen, [No Value; van Keulen, H; Kuiper, PJC

    2002-01-01

    Response of soybean (Glycine max (L.) Merr.) to plant density has occupied a segment of agronomic research for most of the century. Genotype differences have been noted especially in response to planting date, lodging problems and water limitation. There is limited information on the physiological

  3. Responses of potatoes plants inoculated with arbuscular ...

    African Journals Online (AJOL)

    A pot experiment was set to examine the impact of the foliar litter (Hardwickia binata and Azadirachta indica) and an arbuscular mycorrhizal (AM) fungus on the development of two varieties of potato plants (Aida, Atlas). Three litter doses (0, 25 and 50 g) were applied to the pots after bedding plantlets. The plants were ...

  4. Flooding and low oxygen responses in plants

    NARCIS (Netherlands)

    Pedersen, Ole; Perata, Pierdomenico; Voesenek, Laurentius A.C.J.

    2017-01-01

    The world is currently experiencing dramatic increases in flood events impacting on natural vegetation and crops. Flooding often results in low O2 status in root tissues during waterlogging, but sometimes also in shoot tissues when plants become completely submerged. Plants possess a suite of traits

  5. BACKSTEPPING ALGORITHM FOR LINEAR SISO PLANTS UNDER STRUCTURAL UNCERTAINTIES

    Directory of Open Access Journals (Sweden)

    I. B. Furtat

    2016-01-01

    Full Text Available The robust algorithm is proposed for parametric and structurally uncertain linear plants under external bounded disturbances. The structural uncertainty is an unknown dynamic order of the model of plants. The developed algorithm provides plant output tracking for a smooth bounded reference signal with a required accuracy at a finite time. It is assumed that only scalar input and output of the plants are available for measurement, but not their derivatives. For the synthesis of the control algorithm we use a modified backstepping algorithm. The synthesis of control algorithm is separated into rsteps, where ris an upper bound of the relative degree of control plant model. At each step we synthesize auxiliary controls that stabilize each subsystem about a zero. At the last step we synthesize a basic control law, which provides output tracking for smooth reference signal. It is shown that for the implementation of the algorithm we need to use only one filter of the control signal and the simplified control laws obtained by application of the real derivative elements. It allows simplifying significantly the calculation and implementation of the control system. Numerical examples and results of computer simulation are given, illustrating the operation of the proposed scheme.

  6. Respostas de plantas de Eleusine indica sob diferentes condições hídricas a herbicidas inibidores da ACCase Responses of Eleusine indica plants under different water conditions to ACCase-inhibiting herbicides

    Directory of Open Access Journals (Sweden)

    M.R.R. Pereira

    2011-06-01

    Full Text Available Objetivou-se neste estudo avaliar a eficiência de controle de herbicidas inibidores da ACCase aplicados em pós-emergência em plantas de Eleusine indica submetidas a diferentes teores de água no solo. Os experimentos foram conduzidos em casa de vegetação, com a aplicação de três diferentes herbicidas (fluazifop-p-butil, haloxyfop-methyl e sethoxydim + óleo mineral Assist; o delineamento experimental utilizado para cada herbicida foi inteiramente casualizado, com quatro repetições, constituído de um fatorial 3 x 4, sendo a combinação de três manejos hídricos (-0,03, -0,07 e -1,5 MPa e quatro doses desses produtos (100, 50, 25 e 0% da dose recomendada. Os parâmetros fisiológicos avaliados foram: taxa fotossintética, condutância estomática, transpiração, temperatura da folha e matéria seca das plantas. As avaliações visuais de fitotoxicidade foram realizadas aos 14 dias após a aplicação. Os manejos hídricos aplicados não influenciaram o controle das plantas nos tratamentos testados, com exceção do herbicida sethoxydim, que teve sua eficiência hídrica prejudicada quando da deficiência hídrica nas aplicações das doses fracionadas. A taxa fotossintética, a transpiração e a condutância estomática foram maiores em plantas submetidas ao manejo hídrico de 13%, as quais apresentaram as menores temperaturas foliares em relação à temperatura ambiente.The objective of this study to evaluate the control efficiency of ACCase -inhibiting herbicides applied during post-emergence on plants of Eleusine indica under different soil water contents. The experiments were conducted in a greenhouse, with the application of three different herbicides (fluazifop-p-butyl, haloxyfop-methyl and sethoxydim + oil Assist Each herbicide experiment was arranged in a completely randomized design with four replications, consisting of a 3 x 4 factorial scheme, with the water management strategy combinations (-0.03, -0.07 and -1.5 MPa and

  7. Banking efficiency under corporate social responsibilities

    DEFF Research Database (Denmark)

    Ohene-Asare, Kwaku; Asmild, Mette

    2012-01-01

    This paper expands the banking efficiency literature by developing a banking intermediation model that captures both profit-maximizing and Corporate Social Responsibilities (CSR) of banks. Using a data set of 21 banks for each year 2006-2008, we evaluate the relative efficiency of Ghanaian banks...... that are socially responsible may have economic advantages....

  8. Response to recurrent selection under small effective population size

    Directory of Open Access Journals (Sweden)

    Souza Jr. Cláudio Lopes de

    2000-01-01

    Full Text Available A formula was derived for the prediction of the response to recurrent selection when the effective population size (Ne is small. Usually, responses to selection have been estimated by Rs = icsigma²A/sigmaPh, where i, c, sigma²A, and sigmaPh stand for standardized selection differential, parental control, additive variance, and phenotypic standard deviation, respectively. This expression, however, was derived under the assumption of infinite population size. By introducing the effects of finite population size, the expression derived was Rs = [ic(sigma²A + deltaFD1/sigmaPh] - DFID, where deltaF, ID and D1 are the changes in the inbreeding coefficient, the inbreeding depression, and the covariance of additive and homozygous dominance effects, respectively. Thus, the predicted responses to selection based on these expressions will be smaller than those based on the standard procedures for traits with a high level of dominance such as yield. Responses to five cycles of half-sib selection were predicted for maize by both expressions, considering that 100 progenies were evaluated and 10 S1 progenies were recombined, which corresponds to Ne = 10 for each cycle. The accumulated response to selection estimated with the new expression was about 47 and 28% smaller than that based on the standard expression for yield and plant height, respectively. Thus, the expression usually used overestimates the responses to selection, which is in agreement with reported results, because it does not take into account the effective population size that is generally small in recurrent selection programs

  9. RESPONSE OF TOMATO PLANTS EXPOSED TO TREATMENT WITH NANOPARTICLES

    Directory of Open Access Journals (Sweden)

    Tommaso Giordani

    2012-07-01

    Full Text Available In this work the response of Tomato plants cv. Micro-Tom to nanoparticles (NPs treatment was investigated. Tomato seedlings were grown in hydroponic condition and NPs treatments were carried out by adding Fe3O4 or TiO2 NPs to nutrient solution. At the end of treatments, NPs root uptake and tissue deposition were investigated using Environmental Scanning Electron Microscope, equipped with energy dispersive spectroscopy for chemical identification. At morphological level, one week after the beginning of NP treatment, seedlings grown with high concentration of TiO2 NPs showed an abnormal proliferation of root hairs, as compared to the control seedlings and to the seedlings exposed to Fe3O4 NPs, Shoot morphology did not differ in tomato seedlings grown under different conditions and no symptoms of toxicity were observed in NP-treated plants. In order to analyse genetic effects of NPs treatments, RNA transcription was studied in roots of NP-exposed and control plants by Illumina RNA sequencing, evidencing the induction of transposable elements.

  10. The transcription factor IDEF1 regulates the response to and tolerance of iron deficiency in plants

    OpenAIRE

    Kobayashi, Takanori; Ogo, Yuko; Itai, Reiko Nakanishi; Nakanishi, Hiromi; Takahashi, Michiko; Mori, Satoshi; Nishizawa, Naoko K.

    2007-01-01

    Iron is essential for most living organisms and is often the major limiting nutrient for normal growth. Plants induce iron utilization systems under conditions of low iron availability, but the molecular mechanisms of gene regulation under iron deficiency remain largely unknown. We identified the rice transcription factor IDEF1, which specifically binds the iron deficiency-responsive cis-acting element IDE1. IDEF1 belongs to an uncharacterized branch of the plant-specific transcription factor...

  11. Plant Response to Differential Soil Water Content and Salinity

    Science.gov (United States)

    Moradi, A. B.; Dara, A.; Kamai, T.; Ngo, A.; Walker, R.; Hopmans, J. W.

    2011-12-01

    Root-zone soil water content is extremely dynamic, governed by complex and coupled processes such as root uptake, irrigation, evaporation, and leaching. Root uptake of water and nutrients is influenced by these conditions and the processes involved. Plant roots are living and functioning in a dynamic environment that is subjected to extreme changes over relatively short time and small distances. In order to better manage our agricultural resources and cope with increasing constraints of water limitation, environmental concerns and climate change, it is vital to understand plants responses to these changes in their environment. We grew chick pea (Cicer arietinum) plants, in boxes of 30 x 25 x 1 cm dimensions filled with fine sand. Layers of coarse sand (1.5 cm thick) were embedded in the fine-sand media to divide the root growth environment into sections that were hydraulically disconnected from each other. This way, each section could be independently treated with differential levels of water and salinity. The root growth and distribution in the soil was monitored on daily bases using neutron radiography. Daily water uptake was measured by weighing the containers. Changes of soil water content in each section of the containers were calculated from the neutron radiographs. Plants that part of their root system was stressed with drought or salinity showed no change in their daily water uptake rate. The roots in the stressed sections stayed turgid during the stress period and looked healthy in the neutron images. However the uptake rate was severely affected when the soil in the non-stressed section started to dry. The plants were then fully irrigated with water and the water uptake rate recovered to its initial rate shortly after irrigation. The neutron radiographs clearly illustrated the shrinkage and recovery of the roots under stress and the subsequent relief. This cycle was repeated a few times and the same trend could be reproduced. Our results show that plants

  12. Experience with RTD response time testing in nuclear power plants

    International Nuclear Information System (INIS)

    Hashemian, H.M.; Kerlin, T.W.

    1985-01-01

    The reactor coolant temperatures in pressurized water reactors are measured with platinum resistance temperature detectors (RTDs). The information furnished by these RTDs is used for plant protection as well as control. As a part of the plant protection system, the RTDs must respond to temperature changes in a timely fashion. The RTD response time requirements are different for the various plant types. These requirements are specified in the plant technical specifications in terms of an RTd time constant. The current time constant requirements for nuclear plant RTDs varies from 0.5 seconds to 13.0 seconds depending on the type of the plant. Therefore, different types of RTDs are used in different plants to achieve the required time constants. In addition, in-situ response time tests are periodically performed on protective system RTDs to ensure that the in-service time constants are within acceptable limits as the plant is operating. The periodic testing is important because response time degradation may occur while the RTD ages in the process. Recent response time tests in operating plants revealed unacceptable time constants for several protection system RTDs. As a result, these plants had to be shut down to resolve the problem which in one case was due to improper installation and in another case was because of degradation of a thermal compound used in the thermowell

  13. Optimal plant nitrogen use improves model representation of vegetation response to elevated CO2

    Science.gov (United States)

    Caldararu, Silvia; Kern, Melanie; Engel, Jan; Zaehle, Sönke

    2017-04-01

    Existing global vegetation models often cannot accurately represent observed ecosystem behaviour under transient conditions such as elevated atmospheric CO2, a problem that can be attributed to an inflexibility in model representation of plant responses. Plant optimality concepts have been proposed as a solution to this problem as they offer a way to represent plastic plant responses in complex models. Here we present a novel, next generation vegetation model which includes optimal nitrogen allocation to and within the canopy as well as optimal biomass allocation between above- and belowground components in response to nutrient and water availability. The underlying hypothesis is that plants adjust their use of nitrogen in response to environmental conditions and nutrient availability in order to maximise biomass growth. We show that for two FACE (Free Air CO2 enrichment) experiments, the Duke forest and Oak Ridge forest sites, the model can better predict vegetation responses over the duration of the experiment when optimal processes are included. Specifically, under elevated CO2 conditions, the model predicts a lower optimal leaf N concentration as well as increased biomass allocation to fine roots, which, combined with a redistribution of leaf N between the Rubisco and chlorophyll components, leads to a continued NPP response under high CO2, where models with a fixed canopy stoichiometry predict a quick onset of N limitation.Existing global vegetation models often cannot accurately represent observed ecosystem behaviour under transient conditions such as elevated atmospheric CO2, a problem that can be attributed to an inflexibility in model representation of plant responses. Plant optimality concepts have been proposed as a solution to this problem as they offer a way to represent plastic plant responses in complex models. Here we present a novel, next generation vegetation model which includes optimal nitrogen allocation to and within the canopy as well as

  14. Evaluating physiological responses of plants to salinity stress

    KAUST Repository

    Negrão, Sónia

    2016-10-06

    Background Because soil salinity is a major abiotic constraint affecting crop yield, much research has been conducted to develop plants with improved salinity tolerance. Salinity stress impacts many aspects of a plant’s physiology, making it difficult to study in toto. Instead, it is more tractable to dissect the plant’s response into traits that are hypothesized to be involved in the overall tolerance of the plant to salinity. Scope and conclusions We discuss how to quantify the impact of salinity on different traits, such as relative growth rate, water relations, transpiration, transpiration use efficiency, ionic relations, photosynthesis, senescence, yield and yield components. We also suggest some guidelines to assist with the selection of appropriate experimental systems, imposition of salinity stress, and obtaining and analysing relevant physiological data using appropriate indices. We illustrate how these indices can be used to identify relationships amongst the proposed traits to identify which traits are the most important contributors to salinity tolerance. Salinity tolerance is complex and involves many genes, but progress has been made in studying the mechanisms underlying a plant’s response to salinity. Nevertheless, several previous studies on salinity tolerance could have benefited from improved experimental design. We hope that this paper will provide pertinent information to researchers on performing proficient assays and interpreting results from salinity tolerance experiments.

  15. On-line acquisition of plant related and environmental parameters (plant monitoring) in gerbera: determining plant responses

    NARCIS (Netherlands)

    Baas, R.; Slootweg, G.

    2004-01-01

    For on-line plant monitoring equipment to be functional in commercial glasshouse horticulture, relations between sensor readings and plant responses on both the short (days) and long term (weeks) are required. For this reason, systems were installed to monitor rockwool grown gerbera plants on a

  16. Impact of hormonal crosstalk on resistance and fitness of plants under multi-attacker conditions

    Directory of Open Access Journals (Sweden)

    Irene A Vos

    2015-08-01

    Full Text Available The hormone salicylic acid (SA generally induces plant defenses against biotrophic pathogens. Jasmonic acid and its oxylipin derivatives (JAs together with ethylene (ET are generally important hormonal regulators of induced plant defenses against necrotrophic pathogens, whereas JAs together with abscisic acid (ABA are implicated in induced plant defenses against herbivorous insects. Hormonal crosstalk between the different plant defense pathways has often been hypothesized to be a cost-saving strategy that has evolved as a means of the plant to reduce allocation costs by repression of unnecessary defenses, thereby minimizing trade-offs between plant defense and growth. However, proof for this hypothesis has not been demonstrated yet. In this study the impact of defense hormonal crosstalk on disease resistance and fitness of Arabidopsis thaliana when under multi-species attack was investigated. Induction of SA- or JA/ABA-dependent defense responses by the biotrophic pathogen Hyaloperonospora arabidopsidis or the herbivorous insect Pieris rapae, respectively, was shown to reduce the level of induced JA/ET-dependent defense against subsequent infection with the necrotrophic pathogen Botrytis cinerea. However, despite the enhanced susceptibility to this second attacker, no additional long-term negative effects were observed on plant fitness when plants had been challenged by multiple attackers. Similarly, when plants were grown in dense competition stands to enlarge fitness effects of induced defenses, treatment with a combination of SA and MeJA did not cause additional negative effects on plant fitness in comparison to the single MeJA treatment. Together, these data support the notion that defense hormonal crosstalk in plants during multi-attacker interactions allows plants to prioritize their defenses, while limiting the fitness costs associated with induction of defenses.

  17. Plant systemic induced responses mediate interactions between root parasitic nematodes and aboveground herbivorous insects

    Directory of Open Access Journals (Sweden)

    Mesfin eWondafrash

    2013-04-01

    Full Text Available Insects and nematodes are the most diverse and abundant groups of multicellular animals feeding on plants on either side of the soil-air interface. Several herbivore-induced responses are systemic, and hence can influence the preference and performance of organisms in other plant organs. Recent studies show that plants mediate interactions between belowground plant parasitic nematodes and aboveground herbivorous insects. Based on the knowledge of plant responses to pathogens, we review the emerging insights on plant systemic responses against root-feeding nematodes and shoot-feeding insects. We discuss the potential mechanisms of plant-mediated indirect interactions between both groups of organisms and point to gaps in our knowledge. Root-feeding nematodes can positively or negatively affect shoot herbivorous insects, and vice versa. The outcomes of the interactions between these spatially separated herbivore communities appear to be influenced by the feeding strategy of the nematodes and the insects, as well as by host plant susceptibility to both herbivores. The potential mechanisms for these interactions include systemic induced plant defence, interference with the translocation and dynamics of locally induced secondary metabolites, and reallocation of plant nutritional reserves. During evolution, plant parasitic nematodes as well as herbivorous insects have acquired effectors that modify plant defence responses and resource allocation patterns to their advantage. However, it is also known that plants under herbivore attack change the allocation of their resources, e.g. for compensatory growth responses, which may affect the performance of other organisms feeding on the plant. Studying the chemical and molecular basis of these interactions will reveal the molecular mechanisms that are involved. Moreover, it will lead to a better understanding of the ecological relevance of aboveground-belowground interactions, as well as support the

  18. Chromatin changes in response to drought, salinity, heat, and cold stresses in plants

    Directory of Open Access Journals (Sweden)

    Jong-Myong eKim

    2015-03-01

    Full Text Available Chromatin regulation is essential to regulate genes and genome activities. In plants, the alteration of histone modification and DNA methylation are coordinated with changes in the expression of stress-responsive genes to adapt to environmental changes. Several chromatin regulators have been shown to be involved in the regulation of stress-responsive gene networks under abiotic stress conditions. Specific histone modification sites and the histone modifiers that regulate key stress-responsive genes have been identified by genetic and biochemical approaches, revealing the importance of chromatin regulation in plant stress responses. Recent studies have also suggested that histone modification plays an important role in plant stress memory. In this review, we summarize recent progress on the regulation and alteration of histone modification (acetylation, methylation, phosphorylation, and SUMOylation in response to the abiotic stresses, drought, high-salinity, heat, and cold in plants.

  19. Plant methyl salicylate induces defense responses in the rhizobacterium Bacillus subtilis.

    Science.gov (United States)

    Kobayashi, Kazuo

    2015-04-01

    Bacillus subtilis is a rhizobacterium that promotes plant growth and health. Cultivation of B. subtilis with an uprooted weed on solid medium produced pleat-like architectures on colonies near the plant. To test whether plants emit signals that affect B. subtilis colony morphology, we examined the effect of plant-related compounds on colony morphology. Bacillus subtilis formed mucoid colonies specifically in response to methyl salicylate, which is a plant-defense signal released in response to pathogen infection. Methyl salicylate induced mucoid colony formation by stimulating poly-γ-glutamic acid biosynthesis, which formed enclosing capsules that protected the cells from exposure to antimicrobial compounds. Poly-γ-glutamic acid synthesis depended on the DegS-DegU two-component regulatory system, which activated DegSU-dependent gene transcription in response to methyl salicylate. Bacillus subtilis did not induce plant methyl salicylate production, indicating that the most probable source of methyl salicylate in the rhizosphere is pathogen-infected plants. Methyl salicylate induced B. subtilis biosynthesis of the antibiotics bacilysin and fengycin, the latter of which exhibited inhibitory activity against the plant pathogenic fungus Fusarium oxysporum. We propose that B. subtilis may sense plants under pathogen attack via methyl salicylate, and express defense responses that protect both B. subtilis and host plants in the rhizosphere. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  20. Nutrient considerations for Plants grown under Spaceflight conditions.

    Science.gov (United States)

    Levine, H. G.; Krikorian, A. D.

    We present here results on the analysis of 100 mL medium samples extracted from sterilized floral foam Smithers-Oasis Kent OH used to support the growth of both dicotyledonous Haplopappus gracilis n 75 and monocotyledonous Hemerocallis cv Autumn Blaze n 25 aseptic plants in NASA s Plant Growth Unit PGU during the 5-day CHROMEX-01 Space Shuttle flight March 1989 STS-29 At recovery the medium remaining within each of the five foam blocks for both the space flight and ground control experiments was extracted under vacuum filtered and subjected to elemental analyses Concentration levels of some elements remained the same while some decreased and others increased A unique aspect of this experiment was that all plants were either aseptic tissue culture generated plantlets or sterile seedling clones and the design of the PGU facilitated the maintenance of asepsis throughout the mission confirmed by post-flight microbial sampling This permitted the elimination of microbial considerations in the interpretation of the data The significance of these findings for growing plants in altered gravity environments is discussed

  1. Global Climate Change Response Program, Water Yield in Semiarid Environment Under Projected Climate Change

    OpenAIRE

    United States Department of the Interior

    1996-01-01

    This paper presents the practical application of a distributed parameter climate vegetation hydrologic model (CVHM) and its ability to simulate hydrologic response under existing conditions and under assumed CO2-induced climate and vegetation change. Applying the model to the Weber River basin provided a basis for determining the impacts of climate change on the hydrologic response. By using a "what if" scenario this model included the changes in plant transpiration rates and in vegetation ...

  2. New insights into the regulation of aquaporins by the arbuscular mycorrhizal symbiosis in maize plants under drought stress and possible implications for plant performance.

    Science.gov (United States)

    Bárzana, Gloria; Aroca, Ricardo; Bienert, Gerd Patrick; Chaumont, François; Ruiz-Lozano, Juan Manuel

    2014-04-01

    The relationship between modulation by arbuscular mycorrhizae (AM) of aquaporin expression in the host plant and changes in root hydraulic conductance, plant water status, and performance under stressful conditions is not well known. This investigation aimed to elucidate how the AM symbiosis modulates the expression of the whole set of aquaporin genes in maize plants under different growing and drought stress conditions, as well as to characterize some of these aquaporins in order to shed further light on the molecules that may be involved in the mycorrhizal responses to drought. The AM symbiosis regulated a wide number of aquaporins in the host plant, comprising members of the different aquaporin subfamilies. The regulation of these genes depends on the watering conditions and the severity of the drought stress imposed. Some of these aquaporins can transport water and also other molecules which are of physiological importance for plant performance. AM plants grew and developed better than non-AM plants under the different conditions assayed. Thus, for the first time, this study relates the well-known better performance of AM plants under drought stress to not only the water movement in their tissues but also the mobilization of N compounds, glycerol, signaling molecules, or metalloids with a role in abiotic stress tolerance. Future studies should elucidate the specific function of each aquaporin isoform regulated by the AM symbiosis in order to shed further light on how the symbiosis alters the plant fitness under stressful conditions.

  3. Expansion of plants with Crassulacean Acid Metabolism under global environment change

    Science.gov (United States)

    Yu, K.; D'Odorico, P.; Collins, S. L.; Carr, D.

    2016-12-01

    The abundance of plants with Crassulacean Acid Metabolism (CAM) has increased in many drylands worldwide. This is hypothesized to occur because CAM plants store water, take up CO2 at night, exhibit photosynthetic plasticity, and have high water use efficiency. The increased dominance of CAM plants, however, also depends on their competitive relationship with other functional groups, an aspect of CAM plant sensitivity to global environmental change that has remained largely understudied. Here, we investigated the response of CAM plants and their competitive relationships with C3 and C4 plants under global environmental change. We focused on two pairs of CAM and non-CAM species, namely Cylindropuntia imbricata (a constitutive CAM species) and Bouteloua eriopoda (C4 grass), which co-occur in desert grasslands in northern Mexico, and invasive Mesembryanthemum crystallinum (a facultative CAM species) and Bromus mollis (a C3 invasive grass), which coexist in California's coastal grasslands. A set of growth chamber experiments under altered CO2 and water conditions show that C. imbricata outcompeted B. eriopoda under drought conditions, while in well-watered conditions B. eriopoda was a stronger competitor for soil water than C. imbricata. Under drought conditions a more positive response to CO2 enrichment by C. imbricata indirectly disfavored B. eriopoda, which suggests that interspecific competition can outweigh the favorable direct effect of CO2 enrichment on plant growth. A set of greenhouse experiments under water, N, and soil salinity manipulations showed that drought, N deposition, and/or increased soil salinity served as important drivers for success of M. crystallinum invasion, while B. mollis exerted strong competitive effects on M. crystallinum for light and soil nutrients in well-watered conditions. M. crystallinum switched from C3 photosynthesis to CAM photosynthesis as an adaptive strategy in response to moderate intensity of competition from B. mollis, in

  4. Regulation of abiotic and biotic stress responses by plant hormones

    DEFF Research Database (Denmark)

    Grosskinsky, Dominik Kilian; van der Graaff, Eric; Roitsch, Thomas Georg

    2016-01-01

    Plant hormones (phytohormones) are signal molecules produced within the plant, and occur in very low concentrations. In the present chapter, the current knowledge on the regulation of biotic and biotic stress responses by plant hormones is summarized with special focus on the novel insights...... into the complex hormonal crosstalk of classical growth stimulating plant hormones within the naturally occurring biotic and abiotic multistress environment of higher plants. The MAPK- and phytohormone-cascades which comprise a multitude of single molecules on different signalling levels, as well as interactions...

  5. Plant Cell Protolytic Enzymes Activity under Exposure to Lectins of Endophytic and Epiphytic Azospirillum Strains

    Directory of Open Access Journals (Sweden)

    S.A. Alen’kina

    2016-05-01

    Full Text Available We studied the ability of lectins isolated from the surface of the two strains of nitrogen-fixing soil bacteria of the genus Azospirillum, A. brasilense Sp7 (epiphytic and A. brasilense Sp245 (endophytic, to show have a regulating effect on the activity of pectinolytic enzymes in the roots of wheat seedlings. Research results showed that the lectins under study can cause the induction of the activity of polygalacturonase, pectinesterase, pectatlyase from the plant cell wall, thereby ensuring the bacteria penetration in the plant tissues, as well as the induction of plants responses which, being combined with growth-stimulating effect of bacteria, contributes to the formation of plants stability and productivity.

  6. Decommissioning and equipment replacement of nuclear power plants under uncertainty

    International Nuclear Information System (INIS)

    Takashima, Ryuta; Naito, Yuta; Kimura, Hiroshi; Madarame, Haruki

    2007-01-01

    This study examines the optimal timing for the decommissioning and equipment replacement of nuclear power plants. We consider that the firm has two options of decommissioning and equipment replacement, and determines to exercise these options under electricity price uncertainty. This problem is formulated as two optimal stopping problems. The solution of this model provides the value of the nuclear power plant and the threshold values for decommissioning and replacement. The dependence of decommissioning and replacement strategies on uncertainty and each cost is shown. In order to investigate the probability of events for decommissioning and replacement, Monte Carlo calculations are performed. We also show the probability distribution and the conditional expected time for each event. (author)

  7. Mineralogical composition changes of postagrogenic soils under different plant communities.

    Science.gov (United States)

    Churilin, Nikita; Chizhikova, Natalia; Varlamov, Evgheni; Churilina, Alexandra

    2017-04-01

    Plant communities play the leading role in transformation of soil. The need of studying former arable lands increases due to large number of abandoned lands in Russia. It is necessary to study mineralogical composition of soils involved into natural processes to understand the trends of their development after agricultural activities in the past. The aim of the study is to identify changes in mineralogical composition of soils under the influence of different plant communities. Soils were sampled in the south of Arkhangelsk region, Ustyansky district, near Akichkin Pochinok village. Soils are formed on clay moraine of Moscow glaciation. Soil profiles were dug on interfluve. We selected 4 plant communities on different stages of succession: upland meadow with domination of sod grasses (Phleum pratense, Agrostis tenuis), 16-year-old birch forest where dominants are herbaceous plants such as Poa sp., Chamerion angustiflium, Agrostis tenuis, 16-year-old spruce forest with no herbaceous vegetation and 70-year-old bilberry spruce forest with domination of Vaccinium myrtillus and Vaccinium vitis-idaea. To separate soil fractions mineral content. We noticed a clear differentiation of studied soils both in the content of fraction and composition of minerals. Mineralogical composition and major mineral phases correlation of profiles under 70 years and 16 years of spruce forests are different. Mineralogical content in upper part of profile under the young spruce is more differentiated than in old spruce forest: the amount of quartz and kaolinite increases in upper horizon, although in this case the overall pattern of profile formation of clay material during podzolization remains unchanged. There is more substantial desilting under the birch forest, compared with profile under the spruce of same age within top 50 cm. Under the meadow vegetation we've discovered differentiation in mineral composition. Upper horizons contain smectite phase and differ from the underlying

  8. Corporate Social Responsibility Under Authoritarian Capitalism

    DEFF Research Database (Denmark)

    Hofman, Peter S.; Moon, Jeremy; Wu, Bin

    2017-01-01

    This article introduces the concept of corporate social responsibility (CSR) in the seemingly oxymoronic context of Chinese “authoritarian capitalism.” Following an introduction to the emergence of authoritarian capitalism, the article considers the emergence of CSR in China using Matten and Moon’s...

  9. Banking efficiency under corporate social responsibilities

    DEFF Research Database (Denmark)

    Ohene-Asare, Kwaku; Asmild, Mette

    2012-01-01

    This paper expands the banking efficiency literature by developing a banking intermediation model that captures both profit-maximizing and Corporate Social Responsibilities (CSR) of banks. Using a data set of 21 banks for each year 2006-2008, we evaluate the relative efficiency of Ghanaian banks...

  10. Neurochemical mechanisms underlying responses to psychostimulants

    Energy Technology Data Exchange (ETDEWEB)

    Volkow, N.D.; Fowler, J.S.; Hitzemann, R.; Wang, G.J. [Brookhaven National Lab., Upton, NY (United States)]|[State Univ. of New York, Stony Brook, NY (United States)

    1994-11-01

    This study employed positron emission tomography (PET) to investigate biochemical and metabolic characteristics of the brain of individuals which could put them at risk for drug addiction. It takes advantage of the normal variability between individuals in response to psychoactive drugs to investigate relation between mental state, brain neurochemistry and metabolism and the behavioral response to drugs. We discuss its use to assess if there is an association between mental state and dompaminergic reactivity in response to the psychostimulant drug methylphenidate (MP). Changes in synaptic dopamine induced by MP were evaluated with PET and [11C]raclopride, a D{sub 2} receptor radioligand that is sensitive to endogenous dopamine. Methylpphenidate significantly decreased striatal [11C]raclopride binding. The study showed a correlation between the magnitude of the dopamine-induced changes by methylphenidate, and the mental state of the subjects. Subjects reporting high levels of anxiety and restlessness at baseline had larger changes in MP-induced dopamine changes than those that did not. Further investigations on the relation between an individual`s response to a drug and his/her mental state and personality as well as his neurochemical brain composition may enable to understand better differences in drug addiction vulnerability.

  11. Plant growth responses to polypropylene--biocontainers

    Science.gov (United States)

    The influence of bio-fillers incorporated into polypropylene (PP) on the growth of plants was evaluated. Biocontainers were created by injection molding of PP with 25-40% by weight of Osage orange tree, Paulownia tree, coffee tree wood or dried distillers grain and 5% by weight of maleated polypropy...

  12. Plants' responses to drought and shade environments

    African Journals Online (AJOL)

    전병기

    growth of two avocado cultivars. Sci. Hortic. 95:39-50. Cheung CYM, Poolman MG, Fell DA, Ratcliffe RG, Sweetlove LJ (2014). A diel flux balance model captures interactions between light and dark metabolism during Day-Night cycles in C3 and Crassulacean acid metabolism leaves.Plant Physiol. 165:917-929. Dai Y ...

  13. Shared Responsibility under Article 80 CISG

    DEFF Research Database (Denmark)

    Neumann, Thomas

    2009-01-01

    Article 80 exempts from liability in the situation where the promisor's failure to perform has been caused by the promisee. The Article has been insufficiently dealt with in the literature and has been overlooked in case law. The paper demonstrates that article 80 has an independent scope compared...... of shared responsibility in which both the promisor and the promisee seem to have caused the promisor's failure to perform. Article 80 applies to three different case types. Firstly, cases of sole causation by the promisee. Secondly, cases of joint causation by both parties where the consequences of each...... contribution can be delimited. Thirdly, cases of joint causation where the consequences of each party's contribution cannot be delimited (shared responsibility). The third case type is investigated further and it is established that an apportionment based on a comparative evaluation of the parties is called...

  14. Complementary interactions between oxidative stress and auxins control plant growth responses at plant, organ, and cellular level.

    Science.gov (United States)

    Pasternak, Taras; Potters, Geert; Caubergs, Roland; Jansen, Marcel A K

    2005-08-01

    Plant stress responses are a key factor in steering the development of cells, tissues, and organs. However, the stress-induced signal transduction cascades that control localized growth and cell size/differentiation are not well understood. It is reported here that oxidative stress, exerted by paraquat or alloxan, induced localized cell proliferation in intact seedlings, in isolated root segments, and at the single cell level. Analysis of the stress-induced mitotic activity revealed that oxidative stress enhances auxin-dependent growth cycle reactivation. Based on the similarities between responses at plant, tissue, or single cell level, it is hypothesized that a common mechanism of reactive oxygen species enhanced auxin-responsiveness underlies the stress-induced re-orientation of growth, and that stress-induced effects on the protoplast growth cycle are directly relevant in terms of understanding whole plant behaviour.

  15. Variation in Plant Response to Herbivory Underscored by Functional Traits

    OpenAIRE

    Reese, Aspen T.; Ames, Gregory M.; Wright, Justin P.

    2016-01-01

    The effects of herbivory can shape plant communities and evolution. However, the many forms of herbivory costs and the wide variation in herbivory pressure, including across latitudinal gradients, can make predicting the effects of herbivory on different plant species difficult. Functional trait approaches may aid in contextualizing and standardizing the assessment of herbivory impacts. Here we assessed the response of 26 old-field plant species to simulated defoliation in a greenhouse settin...

  16. Plant organellar proteomics in response to dehydration: turning protein repertoire into insights

    Directory of Open Access Journals (Sweden)

    DEEPTI Bhushan GUPTA

    2016-04-01

    Full Text Available Stress adaptation or tolerance in plants is a complex phenomenon involving changes in physiological and metabolic processes. Plants must develop elaborate networks of defense mechanisms, and adapt to and survive for sustainable agriculture. Water-deficit or dehydration is the most critical environmental factor that plants are exposed to during their life cycle, which influences geographical distribution and productivity of many crop species. The cellular responses to dehydration are orchestrated by a series of multidirectional relays of biochemical events at organelle level. The new challenge is to dissect the underlying mechanisms controlling the perception of stress signals and their transmission to cellular machinery for activation of adaptive responses. The completeness of current descriptions of spatial distribution of proteins, the relevance of subcellular locations in diverse functional processes, and the changes of protein abundance in response to dehydration hold the key to understanding how plants cope with such stress conditions. During past decades, organellar proteomics has proved to be useful not only for deciphering reprograming of plant responses to dehydration, but also to dissect stress-responsive pathways. This review summarizes a range of organellar proteomics investigations under dehydration to gain a holistic view of plant responses to water-deficit conditions, which may facilitate future efforts to develop genetically engineered crops for better adaptation.

  17. Reactive oxygen species generation-scavenging and signaling during plant-arbuscular mycorrhizal and Piriformospora indica interaction under stress condition

    Directory of Open Access Journals (Sweden)

    Manoj Nath

    2016-10-01

    Full Text Available A defined balance between the generation and scavenging of reactive oxygen species (ROS is essential to utilize ROS as an adaptive defense response of plants under biotic and abiotic stress conditions. Moreover, ROS are not only a major determinant of stress response but also acts as signaling molecule that regulates various cellular processes including plant-microbe interaction. In particular, rhizosphere constitutes the biologically dynamic zone for plant–microbe interactions which forms a mutual link leading to reciprocal signaling in both the partners. Among plant–microbe interactions, symbiotic associations of arbuscular mycorrhizal fungi (AMF and arbuscular mycorrhizal-like fungus especially Piriformospora indica with plants are well known to improve plant growth by alleviating the stress-impacts and consequently enhance the plant fitness. AMF and P. indica colonization mainly enhances ROS-metabolism, maintains ROS-homeostasis, and thereby averts higher ROS-level accrued inhibition in plant cellular processes and plant growth and survival under stressful environments. This article summarizes the major outcomes of the recent reports on the ROS-generation and scavenging and signaling in biotic-abiotic stressed plants with AMF and P. indica colonization. Overall, a detailed exploration of ROS-signature kinetics during plant-AMF/P. indica interaction can help in designing innovative strategies for improving plant health and productivity under stress conditions.

  18. Bucket Foundation Response Under Various Displacement Rates

    DEFF Research Database (Denmark)

    Vaitkunaite, Evelina; Nielsen, Benjaminn Nordahl; Ibsen, Lars Bo

    2016-01-01

    The present testing program aims at showing the pore pressure response around a bucket foundation skirt as well as the load and displacement change due to ten different displacement rates. Research findings are useful for a numerical model calibration focusing on the design of the upwind foundation...... in a multi-bucket foundation system. The foundation model is at a scale of approximately 1:20 prototype foundation size. The tests are performed in a pressure tank with the foundation model installed in dense sand. Based on the data, the conclusion is that the bucket foundation design in a storm case should...

  19. Plant species responses to oil degradation and toxicity reduction in ...

    African Journals Online (AJOL)

    Plant species responses to oil degradation and toxicity reduction in soil. ... Abstract. A field project located at the Botanical garden of the University of Port Harcourt was designed to evaluate changes in contaminants concentration and toxicity during phytoremediation. Vegetated plots were established by planting different ...

  20. Plant response strategies to stress and disturbance: the case of ...

    Indian Academy of Sciences (India)

    Unknown

    Plant response strategies to stress and disturbance: the case of aquatic plants. MICHÈLE TRÉMOLIÈRES. Center of Vegetal Ecology and Hydrology, CEVH UMR MA 101 ULP/ENGEES,. 28 rue Goethe F-67083 Strasbourg, France. (Email, michele.tremolieres@bota-ulp.u-strasbg.fr). The environmental factors controlling the ...

  1. Giraffe browsing in response to plant traits

    Science.gov (United States)

    Mahenya, Obeid; Ndjamba, Johannes Kambinda; Mathisen, Karen Marie; Skarpe, Christina

    2016-08-01

    Intake rates by large herbivores are governed by among other things plant traits. We used Masai giraffe (Giraffa camelopardalis tippelskirchi Matschie) as study animals, testing whether they as very large browsers would follow the Jarman-Bell principle and maximize intake rate while tolerating low forage quality. We worked in Arusha National Park, Tanzania. We investigated how intake rate was determined by bite mass and bite rate, and show that bite mass and bite rate were determined by plant characteristics, governed by inherent plant traits, plant traits acquired from previous years' browsing, and season. We predicted that; (1) bite mass would be larger in trees without spines than with (2) bite mass would be larger in the wet season than in the dry, (3) bite rate would be higher in spinescent trees than in non-spinescent, (4) bite rate and/or bite mass would increase with previous years' browsing, (5) bite mass, bite rate or browsing time per tree would be highest for high trees with large, although still available canopies. Visual observations were used to collect data on tree attributes, number of bites taken and time of browsing. Sample size was 132 observed giraffe. We found that bite mass was larger in spineless than in spinescent trees and was larger in the wet season than in the dry. Bite rate, but not bite mass, increased with increasing browsing in previous years and was highest on two to three meter high trees and in spinescent trees. Intake rate followed bite mass more than bite rate and was higher in spineless than in spinescent trees, higher in the wet season than in the dry, and tended to increase with tree height. Giraffe did not prioritize the highest intake rate, but browsed much on Acacias giving a high quality diet but a low intake rate.

  2. Genetic and epigenetic control of plant heat responses

    Directory of Open Access Journals (Sweden)

    Junzhong eLiu

    2015-04-01

    Full Text Available Plants have evolved sophisticated genetic and epigenetic regulatory systems to respond quickly to unfavorable environmental conditions such as heat, cold, drought, and pathogen infections. In particular, heat greatly affects plant growth and development, immunity and circadian rhythm, and poses a serious threat to the global food supply. According to temperatures exposing, heat can be usually classified as warm ambient temperature (about 22-27℃, high temperature (27-30℃ and extremely high temperature (37-42℃, also known as heat stress for the model plant Arabidopsis thaliana. The genetic mechanisms of plant responses to heat have been well studied, mainly focusing on elevated ambient temperature-mediated morphological acclimation and acceleration of flowering, modulation of plant immunity and circadian clock by high temperatures, and thermotolerance to heat stress. Recently, great progress has been achieved on epigenetic regulation of heat responses, including DNA methylation, histone modifications, histone variants, ATP-dependent chromatin remodeling, histone chaperones, small RNAs, long non-coding RNAs and other undefined epigenetic mechanisms. These epigenetic modifications regulate the expression of heat-responsive genes and function to prevent heat-related damage. This review focuses on recent progresses regarding the genetic and epigenetic control of heat responses in plants, and pays more attention to the role of the major epigenetic mechanisms in plant heat responses. Further research perspectives are also discussed.

  3. Photosynthetic responses of pea plants (Pisum sativum L. cv. Little ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-08-04

    Aug 4, 2008 ... meteorological parameters, levels of solar radiation as influenced .... three times during vegetative, flowering and reproductive growth stages of pea plants on expanded leaves of the upper canopy under direct sun light. The Pn rates ..... Global Change Environment: The Importance of Different Plant Traits.

  4. Plant Responses to Abiotic Stress Regulated by Histone Deacetylases

    Directory of Open Access Journals (Sweden)

    Ming Luo

    2017-12-01

    Full Text Available In eukaryotic cells, histone acetylation and deacetylation play an important role in the regulation of gene expression. Histone acetylation levels are modulated by histone acetyltransferases and histone deacetylases (HDACs. Recent studies indicate that HDACs play essential roles in the regulation of gene expression in plant response to environmental stress. In this review, we discussed the recent advance regarding the plant HDACs and their functions in the regulation of abiotic stress responses. The role of HDACs in autophagy was also discussed.

  5. Subtle variation in shade avoidance responses may have profound consequences for plant competitiveness.

    Science.gov (United States)

    Bongers, Franca J; Pierik, Ronald; Anten, Niels P R; Evers, Jochem B

    2017-12-21

    Although phenotypic plasticity has been shown to be beneficial for plant competitiveness for light, there is limited knowledge on how variation in these plastic responses plays a role in determining competitiveness. A combination of detailed plant experiments and functional-structural plant (FSP) modelling was used that captures the complex dynamic feedback between the changing plant phenotype and the within-canopy light environment in time and 3-D space. Leaf angle increase (hyponasty) and changes in petiole elongation rates in response to changes in the ratio between red and far-red light, two important shade avoidance responses in Arabidopsis thaliana growing in dense population stands, were chosen as a case study for plant plasticity. Measuring and implementing these responses into an FSP model allowed simulation of plant phenotype as an emergent property of the underlying growth and response mechanisms. Both the experimental and model results showed that substantial differences in competitiveness may arise between genotypes with only marginally different hyponasty or petiole elongation responses, due to the amplification of plant growth differences by small changes in plant phenotype. In addition, this study illustrated that strong competitive responses do not necessarily have to result in a tragedy of the commons; success in competition at the expense of community performance. Together, these findings indicate that selection pressure could probably have played a role in fine-tuning the sensitive shade avoidance responses found in plants. The model approach presented here provides a novel tool to analyse further how natural selection could have acted on the evolution of plastic responses.

  6. Responsiveness of performance and morphological traits to experimental submergence predicts field distribution pattern of wetland plants

    NARCIS (Netherlands)

    Luo, Fang-Li; Huang, Lin; Lei, Ting; Xue, Wei; Li, Hong-Li; Yu, Fei-Hai; Cornelissen, J.H.C.

    2016-01-01

    Question: Plant trait mean values and trait responsiveness to different environmental regimes are both important determinants of plant field distribution, but the degree to which plant trait means vs trait responsiveness predict plant distribution has rarely been compared quantitatively. Because

  7. Remote sensing of plant trait responses to field-based plant-soil feedback using UAV-based optical sensors

    Science.gov (United States)

    van der Meij, Bob; Kooistra, Lammert; Suomalainen, Juha; Barel, Janna M.; De Deyn, Gerlinde B.

    2017-02-01

    Plant responses to biotic and abiotic legacies left in soil by preceding plants is known as plant-soil feedback (PSF). PSF is an important mechanism to explain plant community dynamics and plant performance in natural and agricultural systems. However, most PSF studies are short-term and small-scale due to practical constraints for field-scale quantification of PSF effects, yet field experiments are warranted to assess actual PSF effects under less controlled conditions. Here we used unmanned aerial vehicle (UAV)-based optical sensors to test whether PSF effects on plant traits can be quantified remotely. We established a randomized agro-ecological field experiment in which six different cover crop species and species combinations from three different plant families (Poaceae, Fabaceae, Brassicaceae) were grown. The feedback effects on plant traits were tested in oat (Avena sativa) by quantifying the cover crop legacy effects on key plant traits: height, fresh biomass, nitrogen content, and leaf chlorophyll content. Prior to destructive sampling, hyperspectral data were acquired and used for calibration and independent validation of regression models to retrieve plant traits from optical data. Subsequently, for each trait the model with highest precision and accuracy was selected. We used the hyperspectral analyses to predict the directly measured plant height (RMSE = 5.12 cm, R2 = 0.79), chlorophyll content (RMSE = 0.11 g m-2, R2 = 0.80), N-content (RMSE = 1.94 g m-2, R2 = 0.68), and fresh biomass (RMSE = 0.72 kg m-2, R2 = 0.56). Overall the PSF effects of the different cover crop treatments based on the remote sensing data matched the results based on in situ measurements. The average oat canopy was tallest and its leaf chlorophyll content highest in response to legacy of Vicia sativa monocultures (100 cm, 0.95 g m-2, respectively) and in mixture with Raphanus sativus (100 cm, 1.09 g m-2, respectively), while the lowest values (76 cm, 0.41 g m-2, respectively

  8. Optimal plant water use across temporal scales: bridging eco-hydrological theories and plant eco-physiological responses

    Science.gov (United States)

    Manzoni, S.; Vico, G.; Palmroth, S.; Katul, G. G.; Porporato, A. M.

    2013-12-01

    unpredictable rainfall conditions, plant hydraulic traits (xylem and stomatal response to water availability) and morphological features (leaf and sapwood areas) must be coordinated - thus providing an ecohydrological interpretation of observed coordination (or homeostasis) among hydraulic traits. Moreover, the combinations of hydraulic traits and responses to drought that are optimal are found to depend on both total rainfall and its distribution during the growing season. Both drier conditions and more intense rainfall events interspaced by longer dry periods favor plants with high resistance to cavitation and delayed stomatal closure as soils dry. In contrast, plants in mesic conditions benefit from cavitation prevention through earlier stomatal closure. The proposed ecohydrological optimality criteria can be used as analytical tools to interpret variability in plant water use and predict trends in plant productivity and species composition under future climates.

  9. The Positive Regulatory Roles of the TIFY10 Proteins in Plant Responses to Alkaline Stress

    Science.gov (United States)

    Zhu, Dan; Li, Rongtian; Liu, Xin; Sun, Mingzhe; Wu, Jing; Zhang, Ning; Zhu, Yanming

    2014-01-01

    The TIFY family is a novel plant-specific protein family, and is characterized by a conserved TIFY motif (TIFF/YXG). Our previous studies indicated the potential roles of TIFY10/11 proteins in plant responses to alkaline stress. In the current study, we focused on the regulatory roles and possible physiological and molecular basis of the TIFY10 proteins in plant responses to alkaline stress. We demonstrated the positive function of TIFY10s in alkaline responses by using the AtTIFY10a and AtTIFY10b knockout Arabidopsis, as evidenced by the relatively lower germination rates of attify10a and attify10b mutant seeds under alkaline stress. We also revealed that ectopic expression of GsTIFY10a in Medicago sativa promoted plant growth, and increased the NADP-ME activity, citric acid content and free proline content but decreased the MDA content of transgenic plants under alkaline stress. Furthermore, expression levels of the stress responsive genes including NADP-ME, CS, H+-ppase and P5CS were also up-regulated in GsTIFY10a transgenic plants under alkaline stress. Interestingly, GsTIFY10a overexpression increased the jasmonate content of the transgenic alfalfa. In addition, we showed that neither GsTIFY10a nor GsTIFY10e exhibited transcriptional activity in yeast cells. However, through Y2H and BiFc assays, we demonstrated that GsTIFY10a, not GsTIFY10e, could form homodimers in yeast cells and in living plant cells. As expected, we also demonstrated that GsTIFY10a and GsTIFY10e could heterodimerize with each other in both yeast and plant cells. Taken together, our results provided direct evidence supporting the positive regulatory roles of the TIFY10 proteins in plant responses to alkaline stress. PMID:25375909

  10. The Role of Light in Cucumber Plant Response to a Diurnal Short-Term Temperature Drop

    Directory of Open Access Journals (Sweden)

    E.N. Ikkonen

    2017-05-01

    Full Text Available In greenhouse production a temperature drop concept has become an important tool to control stem elongation of a number of ornamental plant species, bedding plants and vegetable transplants. This concept takes advantage of the fact that, in many species, plant stem elongation is sensitive to a short diurnal temperature drop in the morning or in the end of the night. Here, the role of light in cucumber plant (Cucumis sativus L. response to a diurnal temperature drop has been investigated. Plants were grown under relatively “low” (120 µmol m-2 s-1 PPFD or “high” (320 µmol m-2 s-1 PPFD light intensity. The effect of a 2 h temperature drop from 23° to 9°C, either in the end of the night (in darkness or in the beginning of the day (in light on plant growth, photosynthetic and respiratory activity was studied. Light-demanding and shade-tolerant cucumber hybrids were used in experiments. The results showed differential temperature regulation of plant morphology and photosynthetic activity in light and darkness. A temperature drop in the light led to more pronounced decrease in biometric and photosynthetic parameters of plants than a temperature drop in darkness. Light intensity during plant growth also modified plant response to a temperature drop. In particular, a temperature drop in the night led to a decrease in photosynthetic activity only in plants grown under "low" light. The respiration of the leaves, on the contrary, was intensified as a result of a temperature drop in plants grown under “high" light. Light-demanding and shade-tolerant hybrids had generally similar response to a temperature drop, but some differences were also revealed. Thus, the degree of light inhibition of mitochondrial respiration decreased due to a temperature drop only in the leaves of light-demanding hybrids. They also demonstrated greater reduction of photosynthetic pigment content in response to a temperature drop compared to shade-tolerant plants. This

  11. Plant hydraulic diversity buffers forest ecosystem responses to drought

    Science.gov (United States)

    Anderegg, W.; Konings, A. G.; Trugman, A. T.; Pacala, S. W.; Yu, K.; Sulman, B. N.; Sperry, J.; Bowling, D. R.

    2017-12-01

    Drought impacts carbon, water, and energy cycles in forests and may pose a fundamental threat to forests in future climates. Plant hydraulic transport of water is central to tree drought responses, including curtailing of water loss and the risk of mortality during drought. The effect of biodiversity on ecosystem function has typically been examined in grasslands, yet the diversity of plant hydraulic strategies may influence forests' response to drought. In a combined analysis of eddy covariance measurements, remote-sensing data of plant water content variation, model simulations, and plant hydraulic trait data, we test the degree to which plant water stress schemes influence the carbon cycle and how hydraulic diversity within and across ecosystems affects large-scale drought responses. We find that current plant functional types are not well-suited to capture hydraulic variation and that higher hydraulic diversity buffers ecosystem variation during drought. Our results demonstrate that tree functional diversity, particularly hydraulic diversity, may be critical to simulate in plant functional types in current land surface model projections of future vegetation's response to climate extremes.

  12. Survival Strategies of the Plant-Associated Bacterium Enterobacter sp. Strain EG16 under Cadmium Stress.

    Science.gov (United States)

    Chen, Yanmei; Chao, Yuanqing; Li, Yaying; Lin, Qingqi; Bai, Jun; Tang, Lu; Wang, Shizhong; Ying, Rongrong; Qiu, Rongliang

    2016-01-04

    Plant-associated bacteria are of great interest because of their potential use in phytoremediation. However, their ability to survive and promote plant growth in metal-polluted soils remains unclear. In this study, a soilborne Cd-resistant bacterium was isolated and identified as Enterobacter sp. strain EG16. It tolerates high external Cd concentrations (Cd(2+) MIC, >250 mg liter(-1)) and is able to produce siderophores and the plant hormone indole-3-acetic acid (IAA), both of which contribute to plant growth promotion. Surface biosorption in this strain accounted for 31% of the total Cd accumulated. The potential presence of cadmium sulfide, shown by energy-dispersive X-ray (EDX) analysis, suggested intracellular Cd binding as a Cd response mechanism of the isolate. Cd exposure resulted in global regulation at the transcriptomic level, with the bacterium switching to an energy-conserving mode by inhibiting energy-consuming processes while increasing the production of stress-related proteins. The stress response system included increased import of sulfur and iron, which become deficient under Cd stress, and the redirection of sulfur metabolism to the maintenance of intracellular glutathione levels in response to Cd toxicity. Increased production of siderophores, responding to Cd-induced Fe deficiency, not only is involved in the Cd stress response systems of EG16 but may also play an important role in promoting plant growth as well as alleviating the Cd-induced inhibition of IAA production. The newly isolated strain EG16 may be a suitable candidate for microbially assisted phytoremediation due to its high resistance to Cd and its Cd-induced siderophore production, which is likely to contribute to plant growth promotion. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  13. Physiological and gene expression responses of sunflower (Helianthus annuus L.) plants differ according to irrigation placement.

    Science.gov (United States)

    Aguado, Ana; Capote, Nieves; Romero, Fernando; Dodd, Ian C; Colmenero-Flores, José M

    2014-10-01

    To investigate effects of soil moisture heterogeneity on plant physiology and gene expression in roots and leaves, three treatments were implemented in sunflower plants growing with roots split between two compartments: a control (C) treatment supplying 100% of plant evapotranspiration, and two treatments receiving 50% of plant evapotranspiration, either evenly distributed to both compartments (deficit irrigation - DI) or unevenly distributed to ensure distinct wet and dry compartments (partial rootzone drying - PRD). Plants receiving the same amount of water responded differently under the two irrigation systems. After 3 days, evapotranspiration was similar in C and DI, but 20% less in PRD, concomitant with decreased leaf water potential (Ψleaf) and increased leaf xylem ABA concentration. Six water-stress responsive genes were highly induced in roots growing in the drying soil compartment of PRD plants, and their expression was best correlated with local soil water content. On the other hand, foliar gene expression differed significantly from that of the root and correlated better with xylem ABA concentration and Ψleaf. While the PRD irrigation strategy triggered stronger physiological and molecular responses, suggesting a more intense and systemic stress reaction due to local dehydration of the dry compartment of PRD plants, the DI strategy resulted in similar water savings without strongly inducing these responses. Correlating physiological and molecular responses in PRD/DI plants may provide insights into the severity and location of water deficits and may enable a better understanding of long-distance signalling mechanisms. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  14. Stress Response to High Magnetic Fields in Transgenic Arabidopsis thaliana Plants.

    Science.gov (United States)

    Morgan, A. N.; Watson, B. C.; Maloney, J. R.; Meisel, M. W.; Brooks, J. S.; Paul, A.-L.; Ferl, R. J.

    2000-03-01

    With increasingly greater strength magnetic fields becoming available in research and medicine, the response of living tissue exposed to high magnetic fields has come under investigation. In this experiment, genetically engineered arabidopsis plants were exposed to homogeneous magnetic fields of varying strengths using a superconducting NMR magnet (0 to 9 T) at UF and a resistive magnet (0 to 25 T) at the NHMFL. The engineered plants produce the enzyme β-glucaronidase (GUS) when under stressful environmental conditions. The level of GUS activity is determined through qualitative histochemical assays and quantitative fluorometric assays. The control group of plants experienced baseline levels of GUS activity, but some of the plants that were exposed to magnetic fields in excess of 9 T show increased stress response. Additional information is available at http://www.phys.ufl.edu/ ~meisel/maglev.htm.

  15. Plant water stress: Associations between ethylene and abscisic acid response

    Directory of Open Access Journals (Sweden)

    Carolina Salazar

    2015-08-01

    Full Text Available Agriculture is severely impacted by water stress due either to excess (hypoxia/anoxia or deficit of water availability. Hypoxia/anoxia is associated with oxygen (O2 deficiency or depletion, inducing several anatomical, morphological, physiological, and molecular changes. The majority of these alterations are adaptive mechanisms to cope with low O2 availability; among them, alterations in shoot length, aerenchyma formation and adventitious roots have been described in several studies. The aim of this review was to address the association between abscisic acid (ABA and ethylene in function of water availability in plants. The major physiological responses to low O2 are associated with changes in root respiration, stomatal conductance, photosynthesis, and fermentation pathways in roots. In addition, several changes in gene expression have been associated with pathways that are not present under normal O2 supply. The expression of ethylene receptor genes is up-regulated by low O2, and ethylene seems to have a crucial role in anatomical and physiological effects during hypoxia/anoxia. During O2 depletion, ethylene accumulation down-regulates ABA by inhibiting rate-limiting enzymes in ABA biosynthesis and by activating ABA breakdown to phaseic acid. With regard to water deficit, drought is primarily sensed by the roots, inducing a signal cascade to the shoots via xylem causing physiological and morphological changes. Several genes are regulated up or down with osmotic stress; the majority of these responsive genes can be driven by either an ABA-dependent or ABA-independent pathway. Some studies suggest that ethylene shuts down leaf growth very fast after the plant senses limited water availability. Ethylene accumulation can antagonize the control of gas exchange and leaf growth upon drought and ABA accumulation.

  16. Emerging roles of strigolactones in plant responses to stress and development

    Directory of Open Access Journals (Sweden)

    AMITA ePANDEY

    2016-04-01

    Full Text Available Our environment constantly undergoes changes either natural or manmade affecting growth and development of all the organisms including plants. Plants are sessile in nature and therefore to counter environmental changes such as light, temperature, nutrient and water availability, pathogen, and many others; plants have evolved intricate signaling mechanisms, composed of multiple components including several plant hormones. Research conducted in the last decade has placed Strigolactones (SLs in the growing list of plant hormones involved in coping with environmental changes. SLs are carotenoid derivatives functioning as both endogenous and exogenous signaling molecules in response to various environmental cues. Initially, SLs were discovered as compounds that are harmful to plants due to their role as stimulants in seed germination of parasitic plants, a more beneficial role in plant growth and development was uncovered much later. SLs are required for maintaining plant architecture by regulating shoot and root growth in response to various external stimuli including arbuscular mycorrizal fungi, light, nutrients, and temperature. Moreover, a role for SLs has also been recognized during various abiotic and biotic stress conditions making them suitable target for generating genetically engineered crop plants with improved yield. This review discusses the biosynthesis of SLs and their regulatory and physiological roles in various stress conditions. Understanding of detailed signaling mechanisms of SLs will be an important factor for designing genetically modified crops for overcoming the problem of crop loss under stressful conditions.

  17. On-line acquisition of plant related and environmental parameters (plant monitoring) in gerbera: determining plant responses

    OpenAIRE

    Baas, R.; Slootweg, G.

    2004-01-01

    For on-line plant monitoring equipment to be functional in commercial glasshouse horticulture, relations between sensor readings and plant responses on both the short (days) and long term (weeks) are required. For this reason, systems were installed to monitor rockwool grown gerbera plants on a minute-to-minute basis from July 2002 until April 2003. Data collected included, amongst others, crop transpiration from lysimeter data (2 m2), canopy temperature using infrared sensors, rockwool water...

  18. Characterization of Plant Growth under Single-Wavelength Laser Light Using the Model Plant Arabidopsis Thaliana

    KAUST Repository

    Ooi, Amanda

    2016-12-01

    Indoor horticulture offers a promising solution for sustainable food production and is becoming increasingly widespread. However, it incurs high energy and cost due to the use of artificial lighting such as high-pressure sodium lamps, fluorescent light or increasingly, the light-emitting diodes (LEDs). The energy efficiency and light quality of currently available lighting is suboptimal, therefore less than ideal for sustainable and cost-effective large-scale plant production. Here, we demonstrate the use of high-powered single-wavelength lasers for indoor horticulture. Lasers are highly energy-efficient and can be remotely guided to the site of plant growth, thus reducing on-site heat accumulation. Besides, laser beams can be tailored to match the absorption profiles of different plants. We have developed a prototype laser growth chamber and demonstrate that laser-grown plants can complete a full growth cycle from seed to seed with phenotypes resembling those of plants grown under LEDs. Importantly, the plants have lower expression of proteins diagnostic for light and radiation stress. The phenotypical, biochemical and proteomic data show that the singlewavelength laser light is suitable for plant growth and therefore, potentially able to unlock the advantages of this next generation lighting technology for highly energy-efficient horticulture. Furthermore, stomatal movement partly determines the plant productivity and stress management. Abscisic acid (ABA) induces stomatal closure by promoting net K+-efflux from guard cells through outwardrectifying K+ (K+ out) channels to regulate plant water homeostasis. Here, we show that the Arabidopsis thaliana guard cell outward-rectifying K+ (ATGORK) channel is a direct target for ABA in the regulation of stomatal aperture and hence gas exchange and transpiration. Addition of (±)-ABA, but not the biologically inactive (−)-isomer, increases K+ out channel activity in Vicia faba guard cell protoplast. A similar ABA

  19. Evolutionary responses to climate change in a range expanding plant.

    Science.gov (United States)

    Macel, Mirka; Dostálek, Tomáš; Esch, Sonja; Bucharová, Anna; van Dam, Nicole M; Tielbörger, Katja; Verhoeven, Koen J F; Münzbergová, Zuzana

    2017-06-01

    To understand the biological effects of climate change, it is essential to take into account species' evolutionary responses to their changing environments. Ongoing climate change is resulting in species shifting their geographical distribution ranges poleward. We tested whether a successful range expanding plant has rapidly adapted to the regional conditions in its novel range, and whether adaptation could be driven by herbivores. Furthermore, we investigated if enemy release occurred in the newly colonized areas and whether plant origins differed in herbivore resistance. Plants were cloned and reciprocally transplanted between three experimental sites across the range. Effects of herbivores on plant performance were tested by individually caging plants with either open or closed cages. There was no indication of (regional) adaptation to abiotic conditions. Plants originating from the novel range were always larger than plants from the core distribution at all experimental sites, with or without herbivory. Herbivore damage was highest and not lowest at the experimental sites in the novel range, suggesting no release from enemy impact. Genotypes from the core were more damaged compared to genotypes from newly colonized areas at the most northern site in the novel range, which was dominated by generalist slug herbivory. We also detected subtle shifts in chemical defenses between the plant origins. Genotypes from the novel range had more inducible defenses. Our results suggest that plants that are expanding their range with climate change may evolve increased vigor and altered herbivore resistance in their new range, analogous to invasive plants.

  20. Metabolomic Analysis of Alfalfa (Medicago sativa L.) Root-Symbiotic Rhizobia Responses under Alkali Stress

    OpenAIRE

    Song, Tingting; Xu, Huihui; Sun, Na; Jiang, Liu; Tian, Pu; Yong, Yueyuan; Yang, Weiwei; Cai, Hua; Cui, Guowen

    2017-01-01

    Alkaline salts (e.g., NaHCO3 and Na2CO3) causes more severe morphological and physiological damage to plants than neutral salts (e.g., NaCl and Na2SO4) due to differences in pH. The mechanism by which plants respond to alkali stress is not fully understood, especially in plants having symbotic relationships such as alfalfa (Medicago sativa L.). Therefore, a study was designed to evaluate the metabolic response of the root-nodule symbiosis in alfalfa under alkali stress using comparative metab...

  1. Changes in the Physiological Parameters of SbPIP1-Transformed Wheat Plants under Salt Stress

    Directory of Open Access Journals (Sweden)

    G. H. Yu

    2015-01-01

    Full Text Available The SbPIP1 gene is a new member of the plasma membrane major intrinsic gene family cloned from the euhalophyte Salicornia bigelovii Torr. In order to understand the physiological responses in plants that are mediated by the SbPIP1 gene, SbPIP1-overexpressing wheat lines and WT plants of the wheat cv. Ningmai 13 were treated with salt stress. Several physiological parameters, such as the proline content, the malondialdehyde (MDA content, and the content of soluble sugars and proteins, were compared between SbPIP1-transformed lines and WT plants under normal growth or salt stress conditions. The results indicate that overexpression of the SbPIP1 gene can increase the accumulation of the osmolyte proline, decrease the MDA content, and enhance the soluble sugar biosynthesis in the early period but has no influence on the regulation of soluble protein biosynthesis in wheat. The results suggest that SbPIP1 contributes to salt tolerance by facilitating the accumulation of the osmolyte proline, increasing the antioxidant response, and increasing the biosynthesis of soluble sugar in the early period. These results indicate SbPIP1 plays an important role in the salt stress response. Overexpression of SbPIP1 might be used to improve the salt tolerance of important crop plants.

  2. Phylogenetic analysis of proteins involved in the stringent response in plant cells.

    Science.gov (United States)

    Ito, Doshun; Ihara, Yuta; Nishihara, Hidenori; Masuda, Shinji

    2017-07-01

    The nucleotide (p)ppGpp is a second messenger that controls the stringent response in bacteria. The stringent response modifies expression of a large number of genes and metabolic processes and allows bacteria to survive under fluctuating environmental conditions. Recent genome sequencing analyses have revealed that genes responsible for the stringent response are also found in plants. These include (p)ppGpp synthases and hydrolases, RelA/SpoT homologs (RSHs), and the pppGpp-specific phosphatase GppA/Ppx. However, phylogenetic relationship between enzymes involved in bacterial and plant stringent responses is as yet generally unclear. Here, we investigated the origin and evolution of genes involved in the stringent response in plants. Phylogenetic analysis and primary structures of RSH homologs from different plant phyla (including Embryophyta, Charophyta, Chlorophyta, Rhodophyta and Glaucophyta) indicate that RSH gene families were introduced into plant cells by at least two independent lateral gene transfers from the bacterial Deinococcus-Thermus phylum and an unidentified bacterial phylum; alternatively, they were introduced into a proto-plant cell by a lateral gene transfer from the endosymbiotic cyanobacterium followed by gene loss of an ancestral RSH gene in the cyanobacterial linage. Phylogenetic analysis of gppA/ppx families indicated that plant gppA/ppx homologs form an individual cluster in the phylogenetic tree, and show a sister relationship with some bacterial gppA/ppx homologs. Although RSHs contain a plastidial transit peptide at the N terminus, GppA/Ppx homologs do not, suggesting that plant GppA/Ppx homologs function in the cytosol. These results reveal that a proto-plant cell obtained genes for the stringent response by lateral gene transfer events from different bacterial phyla and have utilized them to control metabolism in plastids and the cytosol.

  3. Plant-pollinator interactions under climate change: The use of spatial and temporal transplants.

    Science.gov (United States)

    Morton, Eva M; Rafferty, Nicole E

    2017-06-01

    Climate change is affecting both the timing of life history events and the spatial distributions of many species, including plants and pollinators. Shifts in phenology and range affect not only individual plant and pollinator species but also interactions among them, with possible negative consequences for both parties due to unfavorable abiotic conditions or mismatches caused by differences in shift magnitude or direction. Ultimately, population extinctions and reductions in pollination services could occur as a result of these climate change-induced shifts, or plants and pollinators could be buffered by plastic or genetic responses or novel interactions. Either scenario will likely involve altered selection pressures, making an understanding of plasticity and local adaptation in space and time especially important. In this review, we discuss two methods for studying plant-pollinator interactions under climate change: spatial and temporal transplants, both of which offer insight into whether plants and pollinators will be able to adapt to novel conditions. We discuss the advantages and limitations of each method and the future possibilities for this area of study. We advocate for consideration of how joint shifts in both dimensions might affect plant-pollinator interactions and point to key insights that can be gained with experimental transplants.

  4. Differential responses of onion and garlic against plant growth regulators

    International Nuclear Information System (INIS)

    Oozunidou, G.; Asif, M.; Giannakuola, A.; Iliass, A.

    2011-01-01

    The effects of Gibberellic acid-GA3, Prohexadione-Calcium, and Ethephon pre-harvest application on yield, biomass production, photosynthetic function, lipid peroxidation and quality characteristics of onion (Allium cepa L.) and garlic (Allium sativum L.) plants were investigated. Shoot length and biomass of onion and garlic, expressed either in fresh or dry weight, increased significantly under GA3, while a progressive decrease under Prohex-Ca and Ethephon occurred. Higher MDA (lipid peroxidation) values were recorded after Prohex-Ca and Ethephon supply on onion and garlic plants; it seems that GA3 treatment prevents lipid peroxidation as measured with the help of the TBARS method. Plants treated with Prohex-Ca and Ethephon revealed higher peroxidase activity compared to control and GA3 treated plants. Considering the results of MDA content and peroxidase activities it can be assumed that GA3 treated plants are slightly protected from the natural course of oxidative stress, which occurs during ageing as observed for control samples. The fluctuations of chlorophyll fluorescence parameters represent a general decline in chloroplasts function after plant growth regulators exposure, whereas in combination to the suppressed chlorophyll content, structural malformations of photo systems may also occur. The production of ascorbic acid, glucose and fructose content seems to be enhanced under GA3 in both species, while their values were depressed under Prohex-Ca and Ethephon. Overall, only GA3 supply leads to a vigorous onion and garlic growth and yield. (author)

  5. Transcriptome analysis reveals regulatory networks underlying differential susceptibility to Botrytis cinerea in response to nitrogen availability in Solanum lycopersicum.

    Directory of Open Access Journals (Sweden)

    Andrea eVega

    2015-11-01

    Full Text Available Nitrogen (N is one of the main limiting nutrients for plant growth and crop yield. It is well documented that changes in nitrate availability, the main N source found in agricultural soils, influences a myriad of developmental programs and processes including the plant defense response. Indeed, many agronomical reports indicate that the plant N nutritional status influences their ability to respond effectively when challenged by different pathogens. However, the molecular mechanisms involved in N-modulation of plant susceptibility to pathogens are poorly characterized. In this work, we show that Solanum lycopersicum defense response to the necrotrophic fungus Botrytis cinerea is affected by plant N availability, with higher susceptibility in nitrate-limiting conditions. Global gene expression responses of tomato against B. cinerea under contrasting nitrate conditions reveals that plant primary metabolism is affected by the fungal infection regardless of N regimes. This result suggests that differential susceptibility to pathogen attack under contrasting N conditions is not only explained by a metabolic alteration. We used a systems biology approach to identify the transcriptional regulatory network implicated in plant response to the fungus infection under contrasting nitrate conditions. Interestingly, hub genes in this network are known key transcription factors involved in ethylene and jasmonic acid signaling. This result positions these hormones as key integrators of nitrate and defense against B. cinerea in tomato plants. Our results provide insights into potential crosstalk mechanisms between necrotrophic defense response and N status in plants.

  6. Rangeland -- plant response to elevated CO2

    International Nuclear Information System (INIS)

    Owensby, C.E.; Coyne, P.I.; Ham, J.M.; Parton, W.; Rice, C.; Auen, L.M.; Adam, N.

    1993-01-01

    Plots of a tallgrass prairie ecosystem were exposed to ambient and twice-ambient CO 2 concentrations in open-top chambers and compared to unchambered ambient CO 2 plots during the entire growing season from 1989 through 1992. Relative root production among treatments was estimated using root ingrowth bags which remained in place throughout the growing season. Latent heat flux was simulated with and without water stress. Botanical composition was estimated annuallyin all treatments. Open-top chambers appeared to reduce latent heat flux and increase water use efficiency similar to elevated CO 2 when water stress was not severe, but under severe water stress, chamber effect on water use efficiency was limited. In natural ecosystems with periodic moisture stress, increased water use efficiency under elevated CO 2 apparently would have a greater impact on productivity than photosynthetic pathway. Root ingrowth biomass was greater in 1990 and 1991 on elevated CO 2 plots compared to ambient or chambered-ambient plots. In 1992, there was no difference in root ingrowth biomass among treatments

  7. Magnesium and cell energetics in plants under anoxia.

    Science.gov (United States)

    Igamberdiev, Abir U; Kleczkowski, Leszek A

    2011-08-01

    Stress conditions (e.g. anoxia) frequently result in a decrease of [ATP] and in an increase of [ADP] and [AMP], with a concomitant increase of [Mg(2+)] and other cations, e.g. Ca(2+). The elevation of [Mg(2+)] is linked to the shift in the apparent equilibrium of adenylate kinase. As a result, enzymes that use Mg(2+) as a cofactor are activated, Ca(2+) activates calcium-dependent signalling pathways, and PP(i) can serve as an alternative energy source in its active form of MgPP(i) or Mg2PP(i). Under anoxic conditions in plants, an important source of PP(i) may come as a result of combined reactions of PK (pyruvate kinase) and PPDK (pyruvate, phosphate dikinase). The PP(i) formed in the PPDK/PK cycle ignites glycolysis in conditions of low [ATP] by involving PP(i)-dependent reactions. This saves ATP and makes metabolism under stress conditions more energy efficient. © The Authors Journal compilation © 2011 Biochemical Society

  8. Interactions between plant hormones and heavy metals responses

    Directory of Open Access Journals (Sweden)

    Lauro Bücker-Neto

    2017-04-01

    Full Text Available Abstract Heavy metals are natural non-biodegradable constituents of the Earth's crust that accumulate and persist indefinitely in the ecosystem as a result of human activities. Since the industrial revolution, the concentration of cadmium, arsenic, lead, mercury and zinc, amongst others, have increasingly contaminated soil and water resources, leading to significant yield losses in plants. These issues have become an important concern of scientific interest. Understanding the molecular and physiological responses of plants to heavy metal stress is critical in order to maximize their productivity. Recent research has extended our view of how plant hormones can regulate and integrate growth responses to various environmental cues in order to sustain life. In the present review we discuss current knowledge about the role of the plant growth hormones abscisic acid, auxin, brassinosteroid and ethylene in signaling pathways, defense mechanisms and alleviation of heavy metal toxicity.

  9. Methodology for Assessment of Inertial Response from Wind Power Plants

    DEFF Research Database (Denmark)

    Altin, Müfit; Teodorescu, Remus; Bak-Jensen, Birgitte

    2012-01-01

    High wind power penetration levels result in additional requirements from wind power in order to improve frequency stability. Replacement of conventional power plants with wind power plants reduces the power system inertia due to the wind turbine technology. Consequently, the rate of change...... of frequency and the maximum frequency deviation increase after a disturbance such as generation loss, load increase, etc. Having no inherent inertial response, wind power plants need additional control concepts in order to provide an additional active power following a disturbance. Several control concepts...... have been implemented in the literature, but the assessment of these control concepts with respect to power system requirements has not been specified. In this paper, a methodology to assess the inertial response from wind power plants is proposed. Accordingly, the proposed methodology is applied...

  10. Evolutionary context for understanding and manipulating plant responses to past, present and future atmospheric [CO2

    Science.gov (United States)

    Leakey, Andrew D. B.; Lau, Jennifer A.

    2012-01-01

    Variation in atmospheric [CO2] is a prominent feature of the environmental history over which vascular plants have evolved. Periods of falling and low [CO2] in the palaeo-record appear to have created selective pressure for important adaptations in modern plants. Today, rising [CO2] is a key component of anthropogenic global environmental change that will impact plants and the ecosystem goods and services they deliver. Currently, there is limited evidence that natural plant populations have evolved in response to contemporary increases in [CO2] in ways that increase plant productivity or fitness, and no evidence for incidental breeding of crop varieties to achieve greater yield enhancement from rising [CO2]. Evolutionary responses to elevated [CO2] have been studied by applying selection in controlled environments, quantitative genetics and trait-based approaches. Findings to date suggest that adaptive changes in plant traits in response to future [CO2] will not be consistently observed across species or environments and will not be large in magnitude compared with physiological and ecological responses to future [CO2]. This lack of evidence for strong evolutionary effects of elevated [CO2] is surprising, given the large effects of elevated [CO2] on plant phenotypes. New studies under more stressful, complex environmental conditions associated with climate change may revise this view. Efforts are underway to engineer plants to: (i) overcome the limitations to photosynthesis from today's [CO2] and (ii) benefit maximally from future, greater [CO2]. Targets range in scale from manipulating the function of a single enzyme (e.g. Rubisco) to adding metabolic pathways from bacteria as well as engineering the structural and functional components necessary for C4 photosynthesis into C3 leaves. Successfully improving plant performance will depend on combining the knowledge of the evolutionary context, cellular basis and physiological integration of plant responses to varying

  11. Fungal elicitors of the phytoalexin response in higher plants

    Science.gov (United States)

    West, Charles A.

    1981-09-01

    Several types of fungal molecules including cell wall polysaccharides, polypeptides, glycoproteins and lipid molecules have been found to serve as elicitors of phytoalexins in higher plants. Recent work has shown that an extracellular enzyme, endopolygalacturonase, from culture filtrates of the fungus Rhizopus stolonifer elicits the biosynthesis of an antifungal antibiotic, casbene, in extracts of treated castor bean ( Ricinus communis L.) seedlings. A suggested mode of action of this elicitor in the plant in which fragments of the plant cell wall released through the catalytic action of the enzyme serve as secondary elicitors to trigger the plant response is proposed on the basis of preliminary observations. Possible modes of interaction of other types of fungal elicitors with plants are also discussed.

  12. Response of sunflower hybrids to management practices under ...

    African Journals Online (AJOL)

    user

    2011-04-04

    Apr 4, 2011 ... practices under irrigated arid-environment. H. Ali, M. Riaz, A. Zahoor and S. ... photo-synthetically active radiation (PAR), yield components and oil contents to planting geometries and nitrogen rates. Experiment 1 ... be fairly stable (Monteith, 1977; Gallagher and Biscoe,. 1978; Kiniry et al., 1989; Hall et al., ...

  13. Physiological responses of planting frozen and thawed Douglas-fir seedlings

    Science.gov (United States)

    M. Anisul Islam; Kent G. Apostol; Douglass F. Jacobs; R. Kasten Dumroese

    2008-01-01

    We studied the short-term (7-day) physiological responses of planting thawed and frozen root plugs of Douglas-fir (Pseudotsuga menziesii) seedlings in 2 separate experiments under cool-moist and warm-dry growing conditions, respectively. Our results showed that shoot water potential, root hydraulic conductance, net photosynthesis (A), and...

  14. Soil and plant responses to pyrogenic organic matter: carbon stability and symbiotic patterns

    NARCIS (Netherlands)

    Sagrilo, E.

    2014-01-01

    Soil and plant responses to pyrogenic organic matter: carbon stability and symbiotic patterns Edvaldo Sagrilo Summary Pyrogenic organic matter (PyOM), also known as biochar, is the product of biomass combustion under low oxygen concentration. There

  15. Responses of northern forest plants to atmospheric changes

    Energy Technology Data Exchange (ETDEWEB)

    Laine, K.; Huttunen, S.; Kauppi, M.; Ohtonen, R.; Laehdesmaeki, P. [Oulu Univ. (Finland). Dept. of Biology

    1996-12-31

    This research programme has been under way since 1990 to study the long-term synergistic effects of air pollutants and changing climatic conditions on the northern forest ecosystem and to increase the knowledge of climatic change and its consequences for the fragile northern nature. Ecological, physiological, morphological and biochemical methods have been used to study the responses of forest trees, dwarf shrubs, lichens and soil biology to environmental changes. The research programme is divided into four subprojects concentrating on different ecosystem levels. The subprojects are: (1) life, growth and survival strategies of northern dwarf shrubs under the pressure of a changing environment, (2) forest trees under the impact of air pollutants, increasing CO{sub 2} and UV-B, (3) susceptibility of lichens to air pollution and climatic change and (4) impact of elevated atmospheric CO{sub 2} and O{sub 3} on soil biology with special reference to carbon allocation and N fixation in symbiotic systems. This report summarizes the results of short-term experiments which showed many ecological and physiological changes in almost all elements of the northern boreal forests. These species-level measurements focused on the key species of the northern boreal forest, which have been thought to be useful in large-scale ecosystem experiments and modelling. The results will also facilitate the further studies on the patterns of plant species distribution and northern ecosystem function with respect to the environmental parameters that are expected to change along with global change (e.g. temperature, airchemistry, UV-B, snow condition)

  16. Recent Molecular Advances on Downstream Plant Responses to Abiotic Stress

    Directory of Open Access Journals (Sweden)

    Cláudia Regina Batista de Souza

    2012-07-01

    Full Text Available Abiotic stresses such as extremes of temperature and pH, high salinity and drought, comprise some of the major factors causing extensive losses to crop production worldwide. Understanding how plants respond and adapt at cellular and molecular levels to continuous environmental changes is a pre-requisite for the generation of resistant or tolerant plants to abiotic stresses. In this review we aimed to present the recent advances on mechanisms of downstream plant responses to abiotic stresses and the use of stress-related genes in the development of genetically engineered crops.

  17. A meta-analysis of the responses of woody and herbaceous plants to elevated ultraviolet-B radiation

    Science.gov (United States)

    Li, Fu-Rong; Peng, Shao-Lin; Chen, Bao-Ming; Hou, Yu-Ping

    2010-01-01

    Numerous studies have examined plant responses to elevated ultraviolet-B radiation at the species level. More than 140 studies conducted within the past three decades were collected for meta-analysis to generalize and examine overall responses of two main life-forms, woody plants and herbaceous plants under two supplemental UV-B levels. The analysis suggested that both life-forms would suffer an overall negative effect in total biomass under the two UV-B levels, and the reduction was 7.0-14.6% of the value at ambient UV-B radiation. Comparing the overall responses under the high supplemental UV-B level with those under the low supplemental UV-B level, woody plants showed no significant changes in any variables. As opposed to this, decreases in herbaceous plant height and specific leaf area as well as increase in herbaceous UV-B-absorbing compounds under the higher UV-B level were significantly greater than those under the lower UV-B level. With continued increases in UV-B levels, the two life-forms would show different response strategies for their different intrinsic capabilities to resist UV-B damage. Woody plants would not invest in large additional amounts of UV-B-absorbing compounds, while herbaceous plants would need to induce stronger defense mechanisms to protect themselves from the associated detrimental effects of UV-B radiation. A higher number of response variables were significantly affected by UV-B radiation for herbaceous plants than for woody plants. Most of the studied variables were not affected significantly under elevated UV-B for woody plants and exhibited very large confidence intervals. Further studies should investigate if the response to elevated UV-B radiation varies between different functional groups of woody species. To sum up, we suggest that as UV-B radiation continues to increase, grassland ecosystems should receive more attention for future vegetation management.

  18. A plant's perspective of extremes: terrestrial plant responses to changing climatic variability.

    Science.gov (United States)

    Reyer, Christopher P O; Leuzinger, Sebastian; Rammig, Anja; Wolf, Annett; Bartholomeus, Ruud P; Bonfante, Antonello; de Lorenzi, Francesca; Dury, Marie; Gloning, Philipp; Abou Jaoudé, Renée; Klein, Tamir; Kuster, Thomas M; Martins, Monica; Niedrist, Georg; Riccardi, Maria; Wohlfahrt, Georg; de Angelis, Paolo; de Dato, Giovanbattista; François, Louis; Menzel, Annette; Pereira, Marízia

    2013-01-01

    We review observational, experimental, and model results on how plants respond to extreme climatic conditions induced by changing climatic variability. Distinguishing between impacts of changing mean climatic conditions and changing climatic variability on terrestrial ecosystems is generally underrated in current studies. The goals of our review are thus (1) to identify plant processes that are vulnerable to changes in the variability of climatic variables rather than to changes in their mean, and (2) to depict/evaluate available study designs to quantify responses of plants to changing climatic variability. We find that phenology is largely affected by changing mean climate but also that impacts of climatic variability are much less studied, although potentially damaging. We note that plant water relations seem to be very vulnerable to extremes driven by changes in temperature and precipitation and that heat-waves and flooding have stronger impacts on physiological processes than changing mean climate. Moreover, interacting phenological and physiological processes are likely to further complicate plant responses to changing climatic variability. Phenological and physiological processes and their interactions culminate in even more sophisticated responses to changing mean climate and climatic variability at the species and community level. Generally, observational studies are well suited to study plant responses to changing mean climate, but less suitable to gain a mechanistic understanding of plant responses to climatic variability. Experiments seem best suited to simulate extreme events. In models, temporal resolution and model structure are crucial to capture plant responses to changing climatic variability. We highlight that a combination of experimental, observational, and/or modeling studies have the potential to overcome important caveats of the respective individual approaches. © 2012 Blackwell Publishing Ltd.

  19. Nematode-plant interactions in grasslands under restoration management

    NARCIS (Netherlands)

    Verschoor, B.C.

    2001-01-01

    Keywords : competition, fertilisation, food quality, grassland, herbivory, nitrogen, nutrients, plant-feeding nematodes, productivity, restoration management, succession, synergism, vegetation

    Plant-feeding nematodes may have a considerable

  20. [Inhibitors of proteolytic enzymes under abiotic stresses in plants (review)].

    Science.gov (United States)

    Mosolov, V V; Valueva, T A

    2011-01-01

    Data on the role of proteolytic enzyme inhibitors in plant adaptation to various unfavorable environmental abiotic factors--water deficiency, salinization of soil, extreme temperatures, etc.--and also probable functions of proteinases inhibitors in natural plant senescense are considered.

  1. Provincial responsibility for carbon emissions in China under different principles

    International Nuclear Information System (INIS)

    Zhang, Youguo

    2015-01-01

    By applying a multi-regional input–output model, the study compares the provincial responsibility for carbon emissions and provincial carbon multipliers in China under seven responsibility-allocating principles, including three basic principles, the production, income and consumption principles, and four shared responsibility principles, the income-weighted, consumption weighted, comprehensive, and weighted comprehensive principles. Empirical results indicate that carbon multipliers of provinces under these principles are significantly different from one another. The carbon multipliers of provinces with higher ratios of carbon intensive sectors in their outputs are also larger. At the same time, the carbon multipliers of the same sector in the provinces are significantly different from one another. Changing the principle causes significant changes in the responsibility for carbon emissions of some provinces, but only slight changes in the responsibilities of some other provinces. However, the responsibilities of provinces with large economic sizes (output) are always the largest, whereas provinces with the smallest economic sizes are always the smallest regardless of the principles. Further, this study proposes a series of regional policies for carbon mitigation according to provincial carbon multipliers and responsibility allocation features under the different principles. - Highlights: • We link regional environmental responsibility to seven benefit principles. • We analyze provincial responsibility for carbon emissions in China. • We also report provincial carbon multipliers under different principles. • We compare the seven principles from the regional perspective. • Policy implications of the study are discussed.

  2. Plant responses to Agrobacterium tumefaciens and crown gall development

    Science.gov (United States)

    Gohlke, Jochen; Deeken, Rosalia

    2014-01-01

    Agrobacterium tumefaciens causes crown gall disease on various plant species by introducing its T-DNA into the genome. Therefore, Agrobacterium has been extensively studied both as a pathogen and an important biotechnological tool. The infection process involves the transfer of T-DNA and virulence proteins into the plant cell. At that time the gene expression patterns of host plants differ depending on the Agrobacterium strain, plant species and cell-type used. Later on, integration of the T-DNA into the plant host genome, expression of the encoded oncogenes, and increase in phytohormone levels induce a fundamental reprogramming of the transformed cells. This results in their proliferation and finally formation of plant tumors. The process of reprogramming is accompanied by altered gene expression, morphology and metabolism. In addition to changes in the transcriptome and metabolome, further genome-wide (“omic”) approaches have recently deepened our understanding of the genetic and epigenetic basis of crown gall tumor formation. This review summarizes the current knowledge about plant responses in the course of tumor development. Special emphasis is placed on the connection between epigenetic, transcriptomic, metabolomic, and morphological changes in the developing tumor. These changes not only result in abnormally proliferating host cells with a heterotrophic and transport-dependent metabolism, but also cause differentiation and serve as mechanisms to balance pathogen defense and adapt to abiotic stress conditions, thereby allowing the coexistence of the crown gall and host plant. PMID:24795740

  3. Trichoderma-plant root colonization: escaping early plant defense responses and activation of the antioxidant machinery for saline stress tolerance.

    Science.gov (United States)

    Brotman, Yariv; Landau, Udi; Cuadros-Inostroza, Álvaro; Tohge, Takayuki; Takayuki, Tohge; Fernie, Alisdair R; Chet, Ilan; Viterbo, Ada; Willmitzer, Lothar

    2013-03-01

    Trichoderma spp. are versatile opportunistic plant symbionts which can colonize the apoplast of plant roots. Microarrays analysis of Arabidopsis thaliana roots inoculated with Trichoderma asperelloides T203, coupled with qPCR analysis of 137 stress responsive genes and transcription factors, revealed wide gene transcript reprogramming, proceeded by a transient repression of the plant immune responses supposedly to allow root colonization. Enhancement in the expression of WRKY18 and WRKY40, which stimulate JA-signaling via suppression of JAZ repressors and negatively regulate the expression of the defense genes FMO1, PAD3 and CYP71A13, was detected in Arabidopsis roots upon Trichoderma colonization. Reduced root colonization was observed in the wrky18/wrky40 double mutant line, while partial phenotypic complementation was achieved by over-expressing WRKY40 in the wrky18 wrky40 background. On the other hand increased colonization rate was found in roots of the FMO1 knockout mutant. Trichoderma spp. stimulate plant growth and resistance to a wide range of adverse environmental conditions. Arabidopsis and cucumber (Cucumis sativus L.) plants treated with Trichoderma prior to salt stress imposition show significantly improved seed germination. In addition, Trichoderma treatment affects the expression of several genes related to osmo-protection and general oxidative stress in roots of both plants. The MDAR gene coding for monodehydroascorbate reductase is significantly up-regulated and, accordingly, the pool of reduced ascorbic acid was found to be increased in Trichoderma treated plants. 1-Aminocyclopropane-1-carboxylate (ACC)-deaminase silenced Trichoderma mutants were less effective in providing tolerance to salt stress, suggesting that Trichoderma, similarly to ACC deaminase producing bacteria, can ameliorate plant growth under conditions of abiotic stress, by lowering ameliorating increases in ethylene levels as well as promoting an elevated antioxidative capacity.

  4. Trichoderma-plant root colonization: escaping early plant defense responses and activation of the antioxidant machinery for saline stress tolerance.

    Directory of Open Access Journals (Sweden)

    Yariv Brotman

    2013-03-01

    Full Text Available Trichoderma spp. are versatile opportunistic plant symbionts which can colonize the apoplast of plant roots. Microarrays analysis of Arabidopsis thaliana roots inoculated with Trichoderma asperelloides T203, coupled with qPCR analysis of 137 stress responsive genes and transcription factors, revealed wide gene transcript reprogramming, proceeded by a transient repression of the plant immune responses supposedly to allow root colonization. Enhancement in the expression of WRKY18 and WRKY40, which stimulate JA-signaling via suppression of JAZ repressors and negatively regulate the expression of the defense genes FMO1, PAD3 and CYP71A13, was detected in Arabidopsis roots upon Trichoderma colonization. Reduced root colonization was observed in the wrky18/wrky40 double mutant line, while partial phenotypic complementation was achieved by over-expressing WRKY40 in the wrky18 wrky40 background. On the other hand increased colonization rate was found in roots of the FMO1 knockout mutant. Trichoderma spp. stimulate plant growth and resistance to a wide range of adverse environmental conditions. Arabidopsis and cucumber (Cucumis sativus L. plants treated with Trichoderma prior to salt stress imposition show significantly improved seed germination. In addition, Trichoderma treatment affects the expression of several genes related to osmo-protection and general oxidative stress in roots of both plants. The MDAR gene coding for monodehydroascorbate reductase is significantly up-regulated and, accordingly, the pool of reduced ascorbic acid was found to be increased in Trichoderma treated plants. 1-Aminocyclopropane-1-carboxylate (ACC-deaminase silenced Trichoderma mutants were less effective in providing tolerance to salt stress, suggesting that Trichoderma, similarly to ACC deaminase producing bacteria, can ameliorate plant growth under conditions of abiotic stress, by lowering ameliorating increases in ethylene levels as well as promoting an elevated

  5. Plant-phytopathogen interactions: bacterial responses to environmental and plant stimuli.

    Science.gov (United States)

    Leonard, Simon; Hommais, Florence; Nasser, William; Reverchon, Sylvie

    2017-05-01

    Plant pathogenic bacteria attack numerous agricultural crops, causing devastating effects on plant productivity and yield. They survive in diverse environments, both in plants, as pathogens, and also outside their hosts as saprophytes. Hence, they are confronted with numerous changing environmental parameters. During infection, plant pathogens have to deal with stressful conditions, such as acidic, oxidative and osmotic stresses; anaerobiosis; plant defenses; and contact with antimicrobial compounds. These adverse conditions can reduce bacterial survival and compromise disease initiation and propagation. Successful bacterial plant pathogens must detect potential hosts and also coordinate their possibly conflicting programs for survival and virulence. Consequently, these bacteria have a strong and finely tuned capacity for sensing and responding to environmental and plant stimuli. This review summarizes our current knowledge of the signals and genetic circuits that affect survival and virulence factor expression in three important and well-studied plant pathogenic bacteria with wide host ranges and the capacity for long-term environmental survival. These are: Ralstonia solanacerarum, a vascular pathogen that causes wilt disease; Agrobacterium tumefaciens, a biotrophic tumorigenic pathogen responsible for crown gall disease and Dickeya, a brute force apoplastic pathogen responsible for soft-rot disease. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  6. Heat-Responsive Photosynthetic and Signaling Pathways in Plants: Insight from Proteomics

    Directory of Open Access Journals (Sweden)

    Xiaoli Wang

    2017-10-01

    Full Text Available Heat stress is a major abiotic stress posing a serious threat to plants. Heat-responsive mechanisms in plants are complicated and fine-tuned. Heat signaling transduction and photosynthesis are highly sensitive. Therefore, a thorough understanding of the molecular mechanism in heat stressed-signaling transduction and photosynthesis is necessary to protect crop yield. Current high-throughput proteomics investigations provide more useful information for underlying heat-responsive signaling pathways and photosynthesis modulation in plants. Several signaling components, such as guanosine triphosphate (GTP-binding protein, nucleoside diphosphate kinase, annexin, and brassinosteroid-insensitive I-kinase domain interacting protein 114, were proposed to be important in heat signaling transduction. Moreover, diverse protein patterns of photosynthetic proteins imply that the modulations of stomatal CO2 exchange, photosystem II, Calvin cycle, ATP synthesis, and chlorophyll biosynthesis are crucial for plant heat tolerance.

  7. Investigations on response time of magnetorheological elastomer under compression mode

    Science.gov (United States)

    Zhu, Mi; Yu, Miao; Qi, Song; Fu, Jie

    2018-05-01

    For efficient fast control of vibration system with magnetorheological elastomer (MRE)-based smart device, the response time of MRE material is the key parameter which directly affects the control performance of the vibration system. For a step coil current excitation, this paper proposed a Maxwell behavior model with time constant λ to describe the normal force response of MRE, and the response time of MRE was extracted through the separation of coil response time. Besides, the transient responses of MRE under compression mode were experimentally investigated, and the effects of (i) applied current, (ii) particle distribution and (iii) compressive strain on the response time of MRE were addressed. The results revealed that the three factors can affect the response characteristic of MRE quite significantly. Besides the intrinsic importance for contributing to the response evaluation and effective design of MRE device, this study may conduce to the optimal design of controller for MRE control system.

  8. Augmenting Plant Immune Responses and Biological Control by Microbial Determinants

    Directory of Open Access Journals (Sweden)

    Sang Moo Lee

    2015-09-01

    Full Text Available Plant have developed sophisticated defence mechanisms against microbial pathogens. The recent accumulated information allow us to understand the nature of plant immune responses followed by recognition of microbial factors/determinants through cutting-edge genomics and multi-omics techniques. However, the practical approaches to sustain plant health using enhancement of plant immunity is yet to be fully appreciated. Here, we overviewed the general concept and representative examples on the plant immunity. The fungal, bacterial, and viral determinants that was previously reported as the triggers of plant immune responses are introduced and described as the potential protocol of biological control. Specifically, the role of chitin, glucan, lipopolysaccharides/extracellular polysaccharides, microbe/pathogen-associated molecular pattern, antibiotics, mimic-phytohormones, N-acyl homoserine lactone, harpin, vitamins, and volatile organic compounds are considered. We hope that this review stimulates scientific community and farmers to broaden their knowledge on the microbial determinant-based biological control and to apply the technology on the integrated pest management program.

  9. Plant surface wax affects parasitoid's response to host footprints

    Science.gov (United States)

    Rostás, Michael; Ruf, Daniel; Zabka, Vanessa; Hildebrandt, Ulrich

    2008-10-01

    The plant surface is the substrate upon which herbivorous insects and natural enemies meet and thus represents the stage for interactions between the three trophic levels. Plant surfaces are covered by an epicuticular wax layer which is highly variable depending on species, cultivar or plant part. Differences in wax chemistry may modulate ecological interactions. We explored whether caterpillars of Spodoptera frugiperda, when walking over a plant surface, leave a chemical trail (kairomones) that can be detected by the parasitoid Cotesia marginiventris. Chemistry and micromorphology of cuticular waxes of two barley eceriferum wax mutants ( cer-za.126, cer-yp.949) and wild-type cv. Bonus (wt) were assessed. The plants were then used to investigate potential surface effects on the detectability of caterpillar kairomones. Here we provide evidence that C. marginiventris responds to chemical footprints of its host. Parasitoids were able to detect the kairomone on wild-type plants and on both cer mutants but the response to cer-yp.949 (reduced wax, high aldehyde fraction) was less pronounced. Experiments with caterpillar-treated wt and mutant leaves offered simultaneously, confirmed this observation: no difference in wasp response was found when wt was tested against cer-za.126 (reduced wax, wt-like chemical composition) but wt was significantly more attractive than cer-yp.949. This demonstrates for the first time that the wax layer can modulate the detectability of host kairomones.

  10. Non-invasive plant growth measurements for detection of blue-light dose response of stem elongation in Chrysanthemum morifolium

    DEFF Research Database (Denmark)

    Kjær, Katrine Heinsvig

    2012-01-01

    . In the present study a non-invasive plant growth sensor (PlantEye, Phenospex B.V, Heerlen, NL) was tested in analysing changes in diurnal stem elongation patterns and plant height in response to the spectral quality of the light environment. Plants were grown in four different LED supplemental lighting...... treatments with 0%, 12.5%, 18.5% and 22.5% blue light under greenhouse conditions in winter (18 h day/4 h night). The non-invasive measurements were carried out automatically every four hour with three repetitions, and supported by manual measurements of plant height every third day. A strong linear relation...... between the non-invasive measurements and manual measurements of plant height was achieved, and a blue-light dose-response showing a decrease in plant height in relation to an increase in blue light was demonstrated. However, the non-invasive plant growth sensor was not able to distinguish between diurnal...

  11. Molecular mechanisms governing differential robustness of development and environmental responses in plants

    DEFF Research Database (Denmark)

    Lachowiec, Jennifer; Queitsch, Christine; Kliebenstein, Daniel James

    2016-01-01

    -level and molecular, that modulate robustness, and discusses their implications for the optimization of plant fitness. Robustness in living systems arises from the structure of genetic networks, the specific molecular functions of the underlying genes, and their interactions. This very same network responsible......-genome duplications, tandem gene duplication and hybridization are emerging as major regulators of robustness in development. Despite their obvious implications for plant evolution and plant breeding, the mechanistic underpinnings by which plants modulate precise levels of robustness, plasticity and evolvability...... to another. Plants, as sessile organisms that undergo continuous development, are particularly dependent on an exquisite fine-tuning of the processes that balance robustness and plasticity to maximize fitness. SCOPE AND CONCLUSIONS: This paper reviews recently identified mechanisms, both systems...

  12. MicroRNAs as regulators in plant metal toxicity response

    Directory of Open Access Journals (Sweden)

    Ana Belen Mendoza-Soto

    2012-05-01

    Full Text Available Metal toxicity is a major stress affecting crop production. This includes metals that are essential for plants (copper, iron, zinc, manganese, and non-essential metals (cadmium, aluminum, cobalt, mercury. A primary common effect of high concentrations of metals such as aluminum, cooper, cadmium or mercury, is root growth inhibition. Metal toxicity triggers the accumulation of reactive oxygen species leading to damage of lipids, proteins and DNA. The plants response to metal toxicity involves several biological processes that require fine and precise regulation at transcriptional and post-transcriptional levels. MicroRNAs (miRNAs are 21 nucleotides non-coding RNAs that regulate gene expression at the post-transcriptional level. A miRNA, incorporated into a RNA induced silencing complex, promotes cleavage of its target mRNA that is recognized by an almost perfect base complementarity. In plants miRNA regulation has been involved in development and also in biotic and abiotic stress responses. We review novel advances in identifying miRNAs related to metal toxicity responses and their potential role according to their targets. Most of the targets for plant metal-responsive miRNAs are transcription factors. Information about metal-responsive miRNAs in different plants points to important regulatory roles of miR319, miR390, miR393 and miR398. The target of miR319 is the TCP transcription factor, implicated in growth control. MiR390 exerts its action through the biogenesis of trans-acting small interference RNAs that, in turn, regulate auxin responsive factors. MiR393 targets the auxin receptors TIR1/AFBs and a bHLH transcription factor. Increasing evidence points to the crucial role of miR398 and its targets Cu/Zn superoxide dismutases in the control of the oxidative stress generated after high metal copper or iron exposure.

  13. Abiotic stress responses in plant roots: a proteomics perspective.

    Science.gov (United States)

    Ghosh, Dipanjana; Xu, Jian

    2014-01-01

    Abiotic stress conditions adversely affect plant growth, resulting in significant decline in crop productivity. To mitigate and recover from the damaging effects of such adverse environmental conditions, plants have evolved various adaptive strategies at cellular and metabolic levels. Most of these strategies involve dynamic changes in protein abundance that can be best explored through proteomics. This review summarizes comparative proteomic studies conducted with roots of various plant species subjected to different abiotic stresses especially drought, salinity, flood, and cold. The main purpose of this article is to highlight and classify the protein level changes in abiotic stress response pathways specifically in plant roots. Shared as well as stressor-specific proteome signatures and adaptive mechanism(s) are simultaneously described. Such a comprehensive account will facilitate the design of genetic engineering strategies that enable the development of broad-spectrum abiotic stress-tolerant crops.

  14. Abiotic stress responses in plant roots: a proteomics perspective

    Directory of Open Access Journals (Sweden)

    Dipanjana eGhosh

    2014-01-01

    Full Text Available Abiotic stress conditions adversely affect plant growth, resulting in significant decline in crop productivity. To mitigate and recover from the damaging effects of such adverse environmental conditions, plants have evolved various adaptive strategies at cellular and metabolic levels. Most of these strategies involve dynamic changes in protein abundance that can be best explored through proteomics. This review summarizes comparative proteomic studies conducted with roots of various plant species subjected to different abiotic stresses especially drought, salinity, flood and cold. The main purpose of this article is to highlight and classify the protein level changes in abiotic stress response pathways specifically in plant roots. Shared as well as stressor-specific proteome signatures and adaptive mechanism(s are simultaneously described. Such a comprehensive account will facilitate the design of genetic engineering strategies that enable the development of broad-spectrum abiotic stress-tolerant crops.

  15. Understanding Inertial and Frequency Response of Wind Power Plants: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, E.; Gevorgian, V.; Singh, M.; Santoso, S.

    2012-07-01

    The objective of this paper is to analyze and quantify the inertia and frequency responses of wind power plants with different wind turbine technologies (particularly those of fixed speed, variable slip with rotor-resistance controls, and variable speed with vector controls).

  16. Heat stress response in plants: a complex game with chaperones ...

    Indian Academy of Sciences (India)

    2004-10-27

    Oct 27, 2004 ... Although functionally equivalent to HsfA1a, HsfA2 is exclusively found after hs induction and represents the dominant Hsf, the ``working horse” of the hs response in plants subjected to repeated cycles of hs and recovery in a hot summer period. Tomato HsfA2 is tightly integrated into a network of interacting ...

  17. Facultative grazing and bioturbation by macrodetritivores alter saltmarsh plant–plant interactions under stress

    NARCIS (Netherlands)

    Howison, Ruth A.; Olff, H.; Puijenbroek, van M.E.B.; Smit, Christian

    2016-01-01

    1.The importance of positive plant–plant interactions is generally suggested to increase towards more stressful conditions, due to mutual stress amelioration between plants. Bioturbating macrodetritivores can also ameliorate stress through bioturbation, but can also become selective herbivores under

  18. Field performance of spider plant ( Cleome gynandra l) under ...

    African Journals Online (AJOL)

    African Journal of Food, Agriculture, Nutrition and Development ... yield were significantly (p<0.05) increased by use of organic and inorganic fertilizers across all planting dates compared to the control where no fertilizers were added. The October 2012 planting date, combined with high rates of organic and inorganic

  19. Right under Their Noses: Native Plants in the Schoolyard.

    Science.gov (United States)

    Reed, Bracken

    2003-01-01

    A Portland (Oregon) middle school teacher teaches an ethnobotany class using plants identified in Lewis and Clark's journals. After months of learning about native plants, Native American culture, and the Lewis and Clark Expedition, the class culminates in a 3-day canoe trip down the Columbia River. A Lewis and Clark Rediscovery grant provides…

  20. Differential oxidative and antioxidative response of duckweed Lemna minor toward plant growth promoting/inhibiting bacteria.

    Science.gov (United States)

    Ishizawa, Hidehiro; Kuroda, Masashi; Morikawa, Masaaki; Ike, Michihiko

    2017-09-01

    Bacteria colonizing the plant rhizosphere are believed to positively or negatively affect the host plant productivity. This feature has inspired researchers to engineer such interactions to enhance crop production. However, it remains to be elucidated whether rhizobacteria influences plant oxidative stress vis-a-vis other environmental stressors, and whether such influence is associated with their growth promoting/inhibiting ability. In this study, two plant growth-promoting bacteria (PGPB) and two plant growth-inhibiting bacteria (PGIB) were separately inoculated into axenic duckweed (Lemna minor) culture under laboratory conditions for 4 and 8 days in order to investigate their effects on plant oxidative stress and antioxidant activities. As previously characterized, the inoculation of PGPB and PGIB strains accelerated and reduced the growth of L. minor, respectively. After 4 and 8 days of cultivation, compared to the PGPB strains, the PGIB strains induced larger amounts of O 2 •- , H 2 O 2 , and malondialdehyde (MDA) in duckweed, although all bacterial strains consistently increased O 2 •- content by two times more than that in the aseptic control plants. Activities of five antioxidant enzymes were also elevated by the inoculation of PGIB, confirming the severe oxidative stress condition in plants. These results suggest that the surface attached bacteria affect differently on host oxidative stress and its response, which degree correlates negatively to their effects on plant growth. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  1. High-Arctic Plant-Herbivore Interactions under Climate Influence

    DEFF Research Database (Denmark)

    Berg, Thomas B.; Schmidt, Niels M.; Høye, Toke Thomas

    2008-01-01

    indirectly, influenced the spatial distribution of herbivores. Additionally, snow distribution directly affected the distribution of herbivores, and hence, in turn, affected the plant community by selective feeding and locally reducing the standing biomass of forage plants. Although only few moth larvae were...... observed at Zackenberg, these had in some cases important local effects owing to their foraging on up to 60% of the flower stands on individual mountain avens. UV-B radiation induces plants to produce secondary plant metabolites, which protects tissues against UV-B damage. This results in lower production......This chapter focuses on a 10-year data series from Zackenberg on the trophic interactions between two characteristic arctic plant species, arctic willow Salix arctica and mountain avens Dryas octopetala, and three herbivore species covering the very scale of size present at Zackenberg, namely...

  2. Understanding the Posttranscriptional Regulation of Plant Responses to Abiotic Stress

    KAUST Repository

    AlShareef, Sahar A.

    2017-06-01

    Constitutive and alternative splicing of pre-mRNAs from multiexonic genes controls the diversity of the proteome; these precisely regulated processes also fine-tune responses to cues related to growth, development, and biotic and abiotic stresses. Recent work showed that AS is pervasive across plant species, with more than 60% of intron-containing genes producing different isoforms. Mammalian cell-based assays have discovered various AS small-molecule inhibitors that perturb splicing and thereby provide invaluable tools for use as chemical probes to uncover the molecular underpinnings of splicing regulation and as potential anticancer compounds. Here, I show that the macrolide Pladienolide B (PB) and herboxidiene (GEX1A) inhibits both constitutive and alternative splicing, mimics an abiotic stress signal, and activates the abscisic acid (ABA) pathway in plants. Moreover, PB and GEX1A activate genome-wide transcriptional patterns involved in abiotic stress responses in plants. PB and GEX1A treatment triggered the ABA signaling pathway, activated ABA-inducible promoters, and led to stomatal closure. Interestingly, PB and GEX1A elicited similar cellular changes, including alterations in the patterns of transcription and splicing, suggesting that these compounds might target the same spliceosome complex in plant cells. This work establishes PB and GEX1A as potent splicing inhibitors in plants that can be used to probe the assembly, dynamics, and molecular functions of the spliceosome and to study the interplay between splicing stress and abiotic stresses, as well as having potential biotechnological applications.

  3. Improved Drought Stress Response in Alfalfa Plants Nodulated by an IAA Over-producing Rhizobium Strain

    Directory of Open Access Journals (Sweden)

    Roberto Defez

    2017-12-01

    Full Text Available The drought–stress response in plant involves the cross-talk between abscisic acid (ABA and other phytohormones, such as jasmonates and ethylene. The auxin indole-3-acetic acid (IAA plays an integral part in plant adaptation to drought stress. Investigation was made to see how the main auxin IAA interacted with other plant hormones under water stress, applied through two different growth conditions (solid and hydroponic. Medicago sativa plants nodulated by the Ensifer meliloti wild type 1021 (Ms-1021 and its IAA-overproducing RD64 derivative strains (Ms-RD64 were subjected to drought stress, comparing their response. When the expression of nifH gene and the activity of the nitrogenase enzyme were measured after stress treatments, Ms-RD64 plants recorded a significantly weaker damage. These results were correlated with a lower biomass reduction, and a higher Rubisco protein level measured for the Ms-RD64-stressed plants as compared to the Ms-1021-stressed ones. It has been verified that the stress response observed for Ms-RD64-stressed plants was related to the production of greater amount of low-molecular-weight osmolytes, such as proline and pinitol, measured in these plants. For the Ms-RD64 plants the immunoblotting analysis of thylakoid membrane proteins showed that some of the photosystem proteins increased after the stress. An increased non-photochemical quenching after the stress was also observed for these plants. The reduced wilting signs observed for these plants were also connected to the significant down-regulation of the MtAA03 gene involved in the ABA biosynthesis, and with the unchanged expression of the two genes (Mt-2g006330 and Mt-8g095330 of ABA signaling. When the expression level of the ethylene-signaling genes was evaluated by qPCR analysis no significant alteration of the key positive regulators was recorded for Ms-RD64-stressed plants. Coherently, these plants accumulated 40% less ethylene as compared to Ms-1021-stressed

  4. Signalling network construction for modelling plant defence response.

    Directory of Open Access Journals (Sweden)

    Dragana Miljkovic

    Full Text Available Plant defence signalling response against various pathogens, including viruses, is a complex phenomenon. In resistant interaction a plant cell perceives the pathogen signal, transduces it within the cell and performs a reprogramming of the cell metabolism leading to the pathogen replication arrest. This work focuses on signalling pathways crucial for the plant defence response, i.e., the salicylic acid, jasmonic acid and ethylene signal transduction pathways, in the Arabidopsis thaliana model plant. The initial signalling network topology was constructed manually by defining the representation formalism, encoding the information from public databases and literature, and composing a pathway diagram. The manually constructed network structure consists of 175 components and 387 reactions. In order to complement the network topology with possibly missing relations, a new approach to automated information extraction from biological literature was developed. This approach, named Bio3graph, allows for automated extraction of biological relations from the literature, resulting in a set of (component1, reaction, component2 triplets and composing a graph structure which can be visualised, compared to the manually constructed topology and examined by the experts. Using a plant defence response vocabulary of components and reaction types, Bio3graph was applied to a set of 9,586 relevant full text articles, resulting in 137 newly detected reactions between the components. Finally, the manually constructed topology and the new reactions were merged to form a network structure consisting of 175 components and 524 reactions. The resulting pathway diagram of plant defence signalling represents a valuable source for further computational modelling and interpretation of omics data. The developed Bio3graph approach, implemented as an executable language processing and graph visualisation workflow, is publically available at http://ropot.ijs.si/bio3graph/and can be

  5. Role of Ethylene and Its Cross Talk with Other Signaling Molecules in Plant Responses to Heavy Metal Stress.

    Science.gov (United States)

    Thao, Nguyen Phuong; Khan, M Iqbal R; Thu, Nguyen Binh Anh; Hoang, Xuan Lan Thi; Asgher, Mohd; Khan, Nafees A; Tran, Lam-Son Phan

    2015-09-01

    Excessive heavy metals (HMs) in agricultural lands cause toxicities to plants, resulting in declines in crop productivity. Recent advances in ethylene biology research have established that ethylene is not only responsible for many important physiological activities in plants but also plays a pivotal role in HM stress tolerance. The manipulation of ethylene in plants to cope with HM stress through various approaches targeting either ethylene biosynthesis or the ethylene signaling pathway has brought promising outcomes. This review covers ethylene production and signal transduction in plant responses to HM stress, cross talk between ethylene and other signaling molecules under adverse HM stress conditions, and approaches to modify ethylene action to improve HM tolerance. From our current understanding about ethylene and its regulatory activities, it is believed that the optimization of endogenous ethylene levels in plants under HM stress would pave the way for developing transgenic crops with improved HM tolerance. © 2015 American Society of Plant Biologists. All Rights Reserved.

  6. Heavy Metal Stress and Some Mechanisms of Plant Defense Response

    Directory of Open Access Journals (Sweden)

    Abolghassem Emamverdian

    2015-01-01

    Full Text Available Unprecedented bioaccumulation and biomagnification of heavy metals (HMs in the environment have become a dilemma for all living organisms including plants. HMs at toxic levels have the capability to interact with several vital cellular biomolecules such as nuclear proteins and DNA, leading to excessive augmentation of reactive oxygen species (ROS. This would inflict serious morphological, metabolic, and physiological anomalies in plants ranging from chlorosis of shoot to lipid peroxidation and protein degradation. In response, plants are equipped with a repertoire of mechanisms to counteract heavy metal (HM toxicity. The key elements of these are chelating metals by forming phytochelatins (PCs or metallothioneins (MTs metal complex at the intra- and intercellular level, which is followed by the removal of HM ions from sensitive sites or vacuolar sequestration of ligand-metal complex. Nonenzymatically synthesized compounds such as proline (Pro are able to strengthen metal-detoxification capacity of intracellular antioxidant enzymes. Another important additive component of plant defense system is symbiotic association with arbuscular mycorrhizal (AM fungi. AM can effectively immobilize HMs and reduce their uptake by host plants via binding metal ions to hyphal cell wall and excreting several extracellular biomolecules. Additionally, AM fungi can enhance activities of antioxidant defense machinery of plants.

  7. Growth and photosynthetic responses of wheat plants grown in space.

    Science.gov (United States)

    Tripathy, B C; Brown, C S; Levine, H G; Krikorian, A D

    1996-03-01

    Growth and photosynthesis of wheat (Triticum aestivum L. cv Super Dwarf) plants grown onboard the space shuttle Discovery for 10 d were examined. Compared to ground control plants, the shoot fresh weight of space-grown seedlings decreased by 25%. Postflight measurements of the O2 evolution/photosynthetic photon flux density response curves of leaf samples revealed that the CO2-saturated photosynthetic rate at saturating light intensities in space-grown plants declined 25% relative to the rate in ground control plants. The relative quantum yield of CO2-saturated photosynthetic O2 evolution measured at limiting light intensities was not significantly affected. In space-grown plants, the light compensation point of the leaves increased by 33%, which likely was due to an increase (27%) in leaf dark-respiration rates. Related experiments with thylakoids isolated from space-grown plants showed that the light-saturated photosynthetic electron transport rate from H2O through photosystems II and I was reduced by 28%. These results demonstrate that photosynthetic functions are affected by the microgravity environment.

  8. Heavy Metal Stress and Some Mechanisms of Plant Defense Response

    Science.gov (United States)

    Emamverdian, Abolghassem; Ding, Yulong; Mokhberdoran, Farzad; Xie, Yinfeng

    2015-01-01

    Unprecedented bioaccumulation and biomagnification of heavy metals (HMs) in the environment have become a dilemma for all living organisms including plants. HMs at toxic levels have the capability to interact with several vital cellular biomolecules such as nuclear proteins and DNA, leading to excessive augmentation of reactive oxygen species (ROS). This would inflict serious morphological, metabolic, and physiological anomalies in plants ranging from chlorosis of shoot to lipid peroxidation and protein degradation. In response, plants are equipped with a repertoire of mechanisms to counteract heavy metal (HM) toxicity. The key elements of these are chelating metals by forming phytochelatins (PCs) or metallothioneins (MTs) metal complex at the intra- and intercellular level, which is followed by the removal of HM ions from sensitive sites or vacuolar sequestration of ligand-metal complex. Nonenzymatically synthesized compounds such as proline (Pro) are able to strengthen metal-detoxification capacity of intracellular antioxidant enzymes. Another important additive component of plant defense system is symbiotic association with arbuscular mycorrhizal (AM) fungi. AM can effectively immobilize HMs and reduce their uptake by host plants via binding metal ions to hyphal cell wall and excreting several extracellular biomolecules. Additionally, AM fungi can enhance activities of antioxidant defense machinery of plants. PMID:25688377

  9. Hydrogel efficiency and physiological responses of seedless citrus cultivars seedlings under water deficit

    Directory of Open Access Journals (Sweden)

    Ester Alice Ferreira

    2014-04-01

    Full Text Available Water is a limiting factor in citrus development which makes hydric replacement a common practice in plantations where its distribution is scarce. The hydroretentor gel has been one of the available technologies for water supply to plants and may also be an alternative that contributes to the rational use of water for planting citrus seedlings. This study evaluated the efficiency of hydrogel as an alternative to minimize the effects of water deficit in seedlings of seedless cultivars of tangerines ('Ortanique', 'Okitsu' and 'Clemenules' and oranges ('Navelina', 'Navelate' and 'Lanelate', all grafted on Poncirus trifoliata. The experiment was carried out in a greenhouse, in a randomized blocks design, where plants with hydrogel were compared to plants under conventional irrigation and also to plants under water deficit, in a triple factorial arrangement. The rates of carbon liquid assimilation, stomatal conductance and transpiration and the ratio between internal and external CO2 concentrations were evaluated. It was verified that the effect of the hydrogel for maintaining the hydric status of citrus seedlings is variable and dependent on physiological mechanisms of response to water deficit. There was no response of 'Ortanique' and 'Navelate'seedlings to the hydrogel application. The hydrogel promoted the recovering and maintenance of the hydric status of 'Okitsu', 'Clemenules', 'Navelina' and 'Lanelate' seedlings, however, these cultivars were sensitive to changes in the water status, with considerable reduction of gas exchange.

  10. Seismic response analysis for a deeply embedded nuclear power plant

    International Nuclear Information System (INIS)

    Chen, W.W.H.; Chatterjee, M.; Day, S.M.

    1979-01-01

    One of the important aspect of the aseimic design of nuclear power plants is the evaluation of the seismic soil-structure interaction effect due to design earthquakes. The soil-structure interaction effect can initiate rocking and result in different soil motions compared to the free field motions, thus significantly affecting the structural response. Two methods are generally used to solve the seismic soil-structure interaction problems: the direct finite element method (FLUSH) and the substructure or impedance approach. This paper presents the results of the horizontal seismic soil-structure interaction analysis using the impedance aproach and the direct finite element method for a deeply embedded nuclear power plant. (orig.)

  11. Differential responses of plant foliage to simulated acid rain

    Energy Technology Data Exchange (ETDEWEB)

    Evans, L.S. (Manhattan Coll., Bronx, NY); Curry, T.M.

    1979-01-01

    Experiments were performed to show the responses of foliage of several clones of Tradescantia sp., Pteridium aquilinum, Quercus palustris, and Glycine max to simulated acid rain. These experiments were performed to (a) predict the relative sensitivities of foliage of these plants to acid rain, and (b) identify leaf surface and anatomical alterations to simulated acid rain that may be used to diagnose acid rain injury. Plants were exposed to simulated rain at pH levels of 5.7, 3.4, 3.1, 2.9, 2.7, 2.5, and 2.3.

  12. Medicinal plants consumption by patients under psychological treatment in a municipality in Chile

    Directory of Open Access Journals (Sweden)

    Rodrigo Ramírez-Tagle

    2018-04-01

    Full Text Available Context: High levels of mental illness are found today in the population of Chile and the consumption of medicinal herbs could be included in the scope of complementary therapies for the treatment of mental illnesses. In Chile there is no information respect to consumption of medicinal herbs in patients under psychological treatment. Aims: To characterize the consumption of medicinal herbs by patients treated in a mental health clinic. Methods: In this quantitative cross-sectional study (n = 100, patients were administered a closed-response survey to determine the frequency of medicinal plant consumption as complementary treatment and subsequently to characterize such consumption. Results: Among the patients surveyed, 36% consumed medicinal herbs to treat a psychological pathology as a complementary treatment. Among those who consumed medicinal herbs, 65% consumed Cannabis sativa (marijuana either exclusively (42% or in conjunction with other plants (23%, 80% reported that their therapist was aware of this behavior, and 35% consumed medicinal herbs once or twice a day. Conclusions: In the present study, there was significant use of medicinal plants by patients treated at the mental health clinic, especially marijuana consuming. This demonstrates the importance of recognizing citizens´ right to free and equal access to healthcare and acknowledging the responsibility of the state to ensure the safety and quality of the services offered to the population.

  13. Plant perception and response to the signal in gravity resistance

    Science.gov (United States)

    Hoson, Takayuki; Soga, Kouichi; Wakabayashi, Kazuyuki; Kamisaka, Seiichiro; Zhang, Yan; Otomi, Yasuhiro; Hashimoto, Takashi; Iida, Hidetoshi

    2012-07-01

    Gravity resistance, mechanical resistance to the gravitational force, is a principal graviresponse in plants, distinct from gravitropism. Plants increase the rigidity of their cell walls in the final step of gravity resistance. We studied cellular events leading to or related to the cell wall changes under hypergravity conditions produced by centrifugation and under microgravity conditions in space. The involvement of mechanosensitive ion channels (mechanoreceptors) in signal perception in gravity resistance has been suggested by experiments with inhibitors. As a candidate for the mechanoreceptor, we identified MCA1 and MCA2 in Arabidopsis. mca-null and MCA-overexpressing seedlings were normal in growth in the dark at 1 g. However, suppression by hypergravity of elongation growth was reduced in hypocotyls of mca-null seedlings. On the contrary, MCA-overexpressing seedlings were hypersensitive to hypergravity. These results suggest that MCAs act as the mechanoreceptor in signal perception of gravity resistance. Cortical microtubules play an essential role in maintenance of normal growth phenotype under hypergravity conditions. In Space Seed experiment in the Kibo Module (PI: S. Kamisaka), we examined the effects of microgravity on growth phenotypes of Arabidopsis tubulin mutant, tua6. Inflorescences of the mutant emerged earlier and elongated rapidly under microgravity conditions than under on-orbit or ground 1 g conditions. Also, the inflorescences grown under microgravity conditions showed higher cell wall extensibilities than the controls. The tubulin mutant thus grew and developed more or less normally under microgravity conditions, supporting the principal role of microtubules also in plant resistance to 1 g gravity. On the other hand, the cellular osmotic properties, as well as the cell wall properties, are important factors determining the rigidity of plant body. Azuki bean epicotyls were capable of maintaining osmoregulation even under hypergravity

  14. Caterpillars induce jasmonates in flowers and alter plant responses to a second attacker

    NARCIS (Netherlands)

    Chrétien, Lucille T.S.; David, Anja; Daikou, Eirini; Boland, Wilhelm; Gershenzon, Jonathan; Giron, David; Dicke, Marcel; Lucas-Barbosa, Dani

    2018-01-01

    In nature, herbivorous insects and plant pathogens are generally abundant when plants are flowering. Thus, plants face a diversity of attackers during their reproductive phase. Plant responses to one attacker can interfere with responses to a second attacker, and phytohormones that orchestrate plant

  15. The Stress Response of Escherichia coli under Microgravity.

    Science.gov (United States)

    Lynch, S.; Matin, A.

    At the onset of adverse environmental conditions, bacteria induce a controlled stress response to enable survival. Escherichia coli induces stress-specific reactions in response to a variety of environmental strains. A family of proteins termed sigma (s) factors is pivotal to the regulation of stress responses in bacteria. In particular Sigma S (ss) regulates several stress responses in E. coli and serves as an important global stress regulatory protein. Under optimal growth conditions, levels of ss are maintained at low cellular concentrations primarily via a proteolytic regulatory mechanism. At the onset of stress, ss levels increase due to increased stability of the molecule, facilitating transcriptional initiation and up regulation of specific stress related proteins. Concentrations of ss can therefore be indicative of cellular stress levels. Recent work by Kendrick et al demonstrated that Salmonella species grown under conditions of simulated microgravity display increased virulence - a stress-related phenotype. Using E. coli as a model system we aim to investigate the stress response elicited by the organism under conditions of simulated microgravity (SMG). SMG is generated in specially constructed rotary cell culture systems termed HARVs (High Aspect Ratio Vessels- Synthecon Inc.). By rotating at constant velocity around a vertical axis an environment is produced in which the gravitational vectors are randomized over the surface of the cell, resulting in an overall-time-averaged gravitational vector of 10-2 x g (4). E. coli cultures grown in HARVs under conditions of normal gravity (NG) and SMG repeatedly display slower growth kinetics under SMG. Western analysis of cells at exponential and stationary phase of growth from both cultures reveal similar levels of ss exist in exponential phase under both SMG and NG conditions. However, during stationary phase, levels of ss are at least 2-fold higher under conditions of SMG as compared to NG. Translational fusion

  16. On 60Co accumulation by freshwater plants under natural conditions

    International Nuclear Information System (INIS)

    Trapeznikov, A.V.; Trapeznikova, V.N.

    1979-01-01

    In search for effective bioindicators of radioactive contamination of cooler-reservoirs in atomic power plants the accumulation of 60 Co by four species of higher aquatic plants most widely distributed in the Urals was studied, namely by Elodea canadensis, Ceratophyllum demersum, Lemna minor and Potamogeton pectinatus. It is shown that such plants as Ceratophyllum demersum and Elodea canadensis having the accumulation coefficients of 60 Co 33,500 and 21,500, respectively, can be recommended as bioindicators of this radionuclide in reservoirs contaminated with radioactive cobalt

  17. Early vs. asymptotic growth responses of herbaceous plants to elevated CO[sub 2

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, S.C.; Jasienski, M.; Bazzaz, F.A. (Harvard Univ., Cambridge, MA (United States). Dept. of Organismic and Evolutionary Biology)

    1999-07-01

    Although many studies have examined the effects of elevated carbon dioxide on plant growth,'' the dynamics of growth involve at least two parameters, namely, an early rate of exponential size increase and an asymptotic size reached late in plant ontogeny. The common practice of quantifying CO[sub 2] responses as a single response ratio thus obscures two qualitatively distinct kinds of effects. The present experiment examines effects of elevated CO[sub 2] on both early and asymptotic growth parameters in eight C[sub 3] herbaceous plant species (Abutilon theophrasti, Cassia obtusifolia, Plantago major, Rumex crispus, Taraxacum officinale, Dactylis glomerata, Lolium multiflorum, and Panicum dichotomoflorum). Plants were grown for 118--172 d in a factorial design of CO[sub 2] (350 and 700 [micro]L/L) and plant density (individually grown vs. high-density monocultures) under edaphic conditions approximating those of coastal areas in Massachusetts. For Abutilon theophrasti, intraspecific patterns of plant response were also assessed using eight genotypes randomly sampled from a natural population and propagated as inbred lines.

  18. Water osmotic absorption in Coleus blumei plants under salinity stress

    Directory of Open Access Journals (Sweden)

    José Ozinaldo Alves de Sena

    2006-11-01

    Full Text Available Three month old Coleus blumei plants in pots were treated with different NaCl concentrations: 0.00, 0.25, 0.50 and 1.00%. To determine the water osmotic absorption, the plants had their stems cut at 10 cm from the soil surface. The remaining stems were linked to glass tubes by flexible rubber tubes. Readings of the water column level in the glass tubes were performed at each 30 minutes, corresponding to the water osmotic absorption, with a total of eleven readings. Other Coleus blumei, with the same age, received the NaCl concentrations, and were evaluated under field conditions in terms of transpiration and stomatal resistance. A randomized complete block analysis was used with five replications. An increase of osmotic absorption was verified for all treatments up to three hours after application. Then a proportional reversion of osmotic absorption to the increases on saline concentration was observed, with a higher effect in the treatment with NaCl 1.00%, showing the increase of water loss by the roots. During this period time, the treatment showed a normal linear growth of the osmotic absorption. Transpiration was reduced proportionally to the increase of salinity concentration.Mudas envasadas de Coleus blumei, com três meses de idade, foram submetidas a diferentes concentrações de cloreto de sódio (NaCl: 0,00; 0,25; 0,50 e 1,00%. Visando determinar a absorção osmótica, as mudas tiveram seus caules cortados a 10 cm acima do solo. Os caules remanescentes foram interligados a tubos de vidro por tubos flexíveis de borracha. Foram feitas leituras (cm a cada 30 minutos dos níveis das colunas de água nos capilares, correspondentes às absorções osmóticas de água, sendo ao todo realizadas onze leituras. Em outro momento, mudas de C. blumei, com a mesma idade das anteriores, receberam as mesmas concentrações de NaCl descritas anteriormente, e, ao ar livre, foram avaliadas em termos de transpiração e resistência estomática, usando

  19. Plant Nucleolar Stress Response, a New Face in the NAC-Dependent Cellular Stress Responses

    Directory of Open Access Journals (Sweden)

    Iwai Ohbayashi

    2018-01-01

    Full Text Available The nucleolus is the most prominent nuclear domain, where the core processes of ribosome biogenesis occur vigorously. All these processes are finely orchestrated by many nucleolar factors to build precisely ribosome particles. In animal cells, perturbations of ribosome biogenesis, mostly accompanied by structural disorders of the nucleolus, cause a kind of cellular stress to induce cell cycle arrest, senescence, or apoptosis, which is called nucleolar stress response. The best-characterized pathway of this stress response involves p53 and MDM2 as key players. p53 is a crucial transcription factor that functions in response to not only nucleolar stress but also other cellular stresses such as DNA damage stress. These cellular stresses release p53 from the inhibition by MDM2, an E3 ubiquitin ligase targeting p53, in various ways, which leads to p53-dependent activation of a set of genes. In plants, genetic impairments of ribosome biogenesis factors or ribosome components have been shown to cause characteristic phenotypes, including a narrow and pointed leaf shape, implying a common signaling pathway connecting ribosomal perturbations and certain aspects of growth and development. Unlike animals, however, plants have neither p53 nor MDM2 family proteins. Then the question arises whether plant cells have a nucleolar stress response pathway. In recent years, it has been reported that several members of the plant-specific transcription factor family NAC play critical roles in the pathways responsive to various cellular stresses. In this mini review, we outline the plant cellular stress response pathways involving NAC transcription factors with reference to the p53-MDM2-dependent pathways of animal cells, and discuss the possible involvement of a plant-unique, NAC-mediated pathway in the nucleolar stress response in plants.

  20. High-Arctic Plant-Herbivore Interactions under Climate Influence

    DEFF Research Database (Denmark)

    Berg, Thomas B.; Schmidt, Niels M.; Høye, Toke Thomas

    This chapter focuses on a 10-year data series from Zackenberg on the trophic interactions between two characteristic arctic plant species, arctic willow Salix arctica and mountain avens Dryas octopetala, and three herbivore species covering the very scale of size present at Zackenberg, namely...... observed at Zackenberg, these had in some cases important local effects owing to their foraging on up to 60% of the flower stands on individual mountain avens. UV-B radiation induces plants to produce secondary plant metabolites, which protects tissues against UV-B damage. This results in lower production...... of anti-herbivore defenses and improves the nutritional quality of the food plants. Zackenberg data on the relationship between variation in density of collared lemmings in winter and UV-B radiation indirectly supports this mechanism, which was originally proposed on the basis of a positive relationship...

  1. Biological effects of plant residues with constrasting chemical compositions on plant and soil under humid tropical conditions

    NARCIS (Netherlands)

    Tian, G.

    1992-01-01

    A study on plant residues with contrasting chemical compositions was conducted under laboratory, growth chamber and humid tropical field conditions to understand the function of the soil fauna in the breakdown of plant residues, the cycling of nutrients, in particular nitrogen, and the

  2. Response of maize ( Zea mays L.) to varied moisture levels under ...

    African Journals Online (AJOL)

    Laboratory and glasshouse trials were used to determine the response of maize plants to varied moisture levels under Striga lutea infestation. Six moisture levels (1.5, 2.0, 2.5, 3.0, 3.5 and 4.0 ml) were applied to striga seed for germination count in the laboratory, while five moisture levels (300, 600, 900, 1200 and 1500 ml) ...

  3. Plant Responses to Brief Touching: A Mechanism for Early Neighbour Detection?

    Directory of Open Access Journals (Sweden)

    Dimitrije Markovic

    Full Text Available In natural habitats plants can be exposed to brief and light contact with neighbouring plants. This mechanical stimulus may represent a cue that induces responses to nearby plants. However, little is known about the effect of touching on plant growth and interaction with insect herbivores. To simulate contact between plants, a soft brush was used to apply light and brief mechanical stimuli to terminal leaves of potato Solanum tuberosum L. The number of non-glandular trichomes on the leaf surface was counted on images made by light microscope while glandular trichomes and pavement cells were counted on images made under scanning electronic microscope. Volatile compounds were identified and quantified using coupled gas chromatography-mass spectrometry (GC-MS. Treated plants changed their pattern of biomass distribution; they had lower stem mass fraction and higher branch and leaf mass fraction than untouched plants. Size, weight and number of tubers were not significantly affected. Touching did not cause trichome damage nor change their total number on touched terminal leaves. However, on primary leaves the number of glandular trichomes and pavement cells was significantly increased. Touching altered the volatile emission of treated plants; they released higher quantities of the sesquiterpenes (E-β-caryophyllene, germacrene D-4-ol and (E-nerolidol, and lower quantities of the terpenes (E-ocimene and linalool, indicating a systemic effect of the treatment. The odour of touched plants was significantly less preferred by the aphids Macrosiphum euphorbiae and Myzus persicae compared to odour of untouched plants. The results suggest that light contact may have a potential role in the detection of neighbouring plants and may affect plant-insect interactions.

  4. Plant Responses to Brief Touching: A Mechanism for Early Neighbour Detection?

    Science.gov (United States)

    Markovic, Dimitrije; Nikolic, Neda; Glinwood, Robert; Seisenbaeva, Gulaim; Ninkovic, Velemir

    2016-01-01

    In natural habitats plants can be exposed to brief and light contact with neighbouring plants. This mechanical stimulus may represent a cue that induces responses to nearby plants. However, little is known about the effect of touching on plant growth and interaction with insect herbivores. To simulate contact between plants, a soft brush was used to apply light and brief mechanical stimuli to terminal leaves of potato Solanum tuberosum L. The number of non-glandular trichomes on the leaf surface was counted on images made by light microscope while glandular trichomes and pavement cells were counted on images made under scanning electronic microscope. Volatile compounds were identified and quantified using coupled gas chromatography–mass spectrometry (GC-MS). Treated plants changed their pattern of biomass distribution; they had lower stem mass fraction and higher branch and leaf mass fraction than untouched plants. Size, weight and number of tubers were not significantly affected. Touching did not cause trichome damage nor change their total number on touched terminal leaves. However, on primary leaves the number of glandular trichomes and pavement cells was significantly increased. Touching altered the volatile emission of treated plants; they released higher quantities of the sesquiterpenes (E)-β-caryophyllene, germacrene D-4-ol and (E)-nerolidol, and lower quantities of the terpenes (E)-ocimene and linalool, indicating a systemic effect of the treatment. The odour of touched plants was significantly less preferred by the aphids Macrosiphum euphorbiae and Myzus persicae compared to odour of untouched plants. The results suggest that light contact may have a potential role in the detection of neighbouring plants and may affect plant-insect interactions. PMID:27828995

  5. Response of a Light Aircraft Under Gust Loads

    Directory of Open Access Journals (Sweden)

    P. Chudý

    2004-01-01

    Full Text Available This project presents work performed by the Institute of Aerospace Engineering, Brno University of Technology. The primary purpose of this work was to estimate the aeroelastic response of a light aircraft under gust loads. In the past, the gust response has been investigated using the Pratt - Walker formula. This formula is derived from the response of a rigid airplane to a discrete gust. However, the Pratt-Walker formula does not capture either the stochastic nature of continuous turbulence or the effects of structural flexibility. The analysis described here was performed using the advanced FEM software package MSC Nastran.

  6. Vibration Control of Nuclear Power Plant Piping System Using Stockbridge Damper under Earthquakes

    Directory of Open Access Journals (Sweden)

    Seongkyu Chang

    2016-01-01

    Full Text Available Generally the piping system of a nuclear power plant (NPP has to be designed for normal loads such as dead weight, internal pressure, temperature, and accidental loads such as earthquake. In the proposed paper, effect of Stockbridge damper to mitigate the response of piping system of NPP subjected to earthquake is studied. Finite element analysis of piping system with and without Stockbridge damper using commercial software SAP2000 is performed. Vertical and horizontal components of earthquakes such as El Centro, California, and Northridge are used in the piping analysis. A sine sweep wave is also used to investigate the control effects on the piping system under wide frequency range. It is found that the proposed Stockbridge damper can reduce the seismic response of piping system subjected to earthquake loading.

  7. Metabolomic Analysis of Alfalfa (Medicago sativa L. Root-Symbiotic Rhizobia Responses under Alkali Stress

    Directory of Open Access Journals (Sweden)

    Tingting Song

    2017-07-01

    Full Text Available Alkaline salts (e.g., NaHCO3 and Na2CO3 causes more severe morphological and physiological damage to plants than neutral salts (e.g., NaCl and Na2SO4 due to differences in pH. The mechanism by which plants respond to alkali stress is not fully understood, especially in plants having symbotic relationships such as alfalfa (Medicago sativa L.. Therefore, a study was designed to evaluate the metabolic response of the root-nodule symbiosis in alfalfa under alkali stress using comparative metabolomics. Rhizobium-nodulized (RI group and non-nodulized (NI group alfalfa roots were treated with 200 mmol/L NaHCO3 and, roots samples were analyzed for malondialdehydyde (MDA, proline, glutathione (GSH, superoxide dismutase (SOD, and peroxidase (POD content. Additionally, metabolite profiling was conducted using gas chromatography combined with time-of-flight mass spectrometry (GC/TOF-MS. Phenotypically, the RI alfalfa exhibited a greater resistance to alkali stress than the NI plants examined. Physiological analysis and metabolic profiling revealed that RI plants accumulated more antioxidants (SOD, POD, GSH, osmolytes (sugar, glycols, proline, organic acids (succinic acid, fumaric acid, and alpha-ketoglutaric acid, and metabolites that are involved in nitrogen fixation. Our pairwise metabolomics comparisons revealed that RI alfalfa plants exhibited a distinct metabolic profile associated with alkali putative tolerance relative to NI alfalfa plants. Data provide new information about the relationship between non-nodulized, rhizobium-nodulized alfalfa and alkali resistance.

  8. Metabolomic Analysis of Alfalfa (Medicago sativa L.) Root-Symbiotic Rhizobia Responses under Alkali Stress.

    Science.gov (United States)

    Song, Tingting; Xu, Huihui; Sun, Na; Jiang, Liu; Tian, Pu; Yong, Yueyuan; Yang, Weiwei; Cai, Hua; Cui, Guowen

    2017-01-01

    Alkaline salts (e.g., NaHCO 3 and Na 2 CO 3 ) causes more severe morphological and physiological damage to plants than neutral salts (e.g., NaCl and Na 2 SO 4 ) due to differences in pH. The mechanism by which plants respond to alkali stress is not fully understood, especially in plants having symbotic relationships such as alfalfa ( Medicago sativa L.). Therefore, a study was designed to evaluate the metabolic response of the root-nodule symbiosis in alfalfa under alkali stress using comparative metabolomics. Rhizobium-nodulized (RI group) and non-nodulized (NI group) alfalfa roots were treated with 200 mmol/L NaHCO 3 and, roots samples were analyzed for malondialdehydyde (MDA), proline, glutathione (GSH), superoxide dismutase (SOD), and peroxidase (POD) content. Additionally, metabolite profiling was conducted using gas chromatography combined with time-of-flight mass spectrometry (GC/TOF-MS). Phenotypically, the RI alfalfa exhibited a greater resistance to alkali stress than the NI plants examined. Physiological analysis and metabolic profiling revealed that RI plants accumulated more antioxidants (SOD, POD, GSH), osmolytes (sugar, glycols, proline), organic acids (succinic acid, fumaric acid, and alpha-ketoglutaric acid), and metabolites that are involved in nitrogen fixation. Our pairwise metabolomics comparisons revealed that RI alfalfa plants exhibited a distinct metabolic profile associated with alkali putative tolerance relative to NI alfalfa plants. Data provide new information about the relationship between non-nodulized, rhizobium-nodulized alfalfa and alkali resistance.

  9. Physiological response of lovage (levisticum officinale, koch) plant to gamma radiation and organic fertilizers

    International Nuclear Information System (INIS)

    Taha, A.T.A.

    2009-01-01

    The main objective of this work is to study physiological response of lovage plant to gamma radiation and organic fertilizers.Two field experiments were conduct under conditions of newly reclaimed soil (sandy loam soil) during two successive seasons (2003/2004 and 2004/2005) in experimental farm , NRC,AEA Inshas. lovage fruits were irradiated before sowing with gamma rays at 0,20,40,60 and 80 Gy. Before planting farm yard manure (FYM) at rates of 0,20,30 and 40 m 3 /fed. Was applied to soil in combination with gamma doses in the first experiment, in the second one, chicken manure at 0,10,15 and 20 m 3 /fed. was added to soil before planting in combination with the same used gamma doses in first experiment. Growth of lovage plants was considerably stimulated by irradiating fruits before sowing with low gamma doses, in particularly at 60 Gy, which greatly increased plant height, number of branches/plant, stem thickness and dry matter yield of shoots. Similar trend was also observed with leaf chlorophyll content which increased due to low gamma doses . Low gamma doses markedly encouraged nutrients uptake by lovage plants which increased levels and total contents of N, P, K, Fe,Zn and Mn in plant shoots. Fruits yield, volatile oil % and oil yield and fruits index value were increased by low gamma doses particularly at 60 Gy.

  10. Plant genetic and molecular responses to water deficit

    Directory of Open Access Journals (Sweden)

    Silvio Salvi

    2011-02-01

    Full Text Available Plant productivity is severely affected by unfavourable environmental conditions (biotic and abiotic stresses. Among others, water deficit is the plant stress condition which mostly limits the quality and the quantity of plant products. Tolerance to water deficit is a polygenic trait strictly dependent on the coordinated expression of a large set of genes coding for proteins directly involved in stress-induced protection/repair mechanisms (dehydrins, chaperonins, enzymes for the synthesis of osmoprotectants and detoxifying compounds, and others as well as genes involved in transducing the stress signal and regulating gene expression (transcription factors, kinases, phosphatases. Recently, research activities in the field evolved from the study of single genes directly involved in cellular stress tolerance (functional genes to the identification and characterization of key regulatory genes involved in stress perception and transduction and able to rapidly and efficiently activate the complex gene network involved in the response to stress. The complexity of the events occurring in response to stress have been recently approached by genomics tools; in fact the analysis of transcriptome, proteome and metabolome of a plant tissue/cell in response to stress already allowed to have a global view of the cellular and molecular events occurring in response to water deficit, by the identification of genes activated and co-regulated by the stress conditions and the characterization of new signalling pathways. Moreover the recent application of forward and reverse genetic approaches, trough mutant collection development, screening and characterization, is giving a tremendous impulse to the identification of gene functions with key role in stress tolerance. The integration of data obtained by high-throughput genomic approaches, by means of powerful informatic tools, is allowing nowadays to rapidly identify of major genes/QTLs involved in stress tolerance

  11. Nanosecond electric pulses trigger actin responses in plant cells

    International Nuclear Information System (INIS)

    Berghoefer, Thomas; Eing, Christian; Flickinger, Bianca; Hohenberger, Petra; Wegner, Lars H.; Frey, Wolfgang; Nick, Peter

    2009-01-01

    We have analyzed the cellular effects of nanosecond pulsed electrical fields on plant cells using fluorescently tagged marker lines in the tobacco cell line BY-2 and confocal laser scanning microscopy. We observe a disintegration of the cytoskeleton in the cell cortex, followed by contraction of actin filaments towards the nucleus, and disintegration of the nuclear envelope. These responses are accompanied by irreversible permeabilization of the plasma membrane manifest as uptake of Trypan Blue. By pretreatment with the actin-stabilizing drug phalloidin, the detachment of transvacuolar actin from the cell periphery can be suppressed, and this treatment can also suppress the irreversible perforation of the plasma membrane. We discuss these findings in terms of a model, where nanosecond pulsed electric fields trigger actin responses that are key events in the plant-specific form of programmed cell death.

  12. Separating the role of biotic interactions and climate in determining adaptive response of plants to climate change.

    Science.gov (United States)

    Tomiolo, Sara; Van der Putten, Wim H; Tielbörger, Katja

    2015-05-01

    Altered rainfall regimes will greatly affect the response of plant species to climate change. However, little is known about how direct effects of changing precipitation on plant performance may depend on other abiotic factors and biotic interactions. We used reciprocal transplants between climatically very different sites with simultaneous manipulation of soil, plant population origin, and neighbor conditions to evaluate local adaptation and possible adaptive response of four Eastern Mediterranean annual plant species to climate change. The effect of site on plant performance was negligible, but soil origin had a strong effect on fecundity, most likely due to differential water retaining ability. Competition by neighbors strongly reduced fitness. We separated the effects of the abiotic and biotic soil properties on plant performance by repeating the field experiment in a greenhouse under homogenous environmental conditions and including a soil biota manipulation treatment. As in the field, plant performance differed among soil origins and neighbor treatments. Moreover, we found plant species-specific responses to soil biota that may be best explained by the differential sensitivity to negative and positive soil biota effects. Overall, under the conditions of our experiment with two contrasting sites, biotic interactions had a strong effect on plant fitness that interacted with and eventually overrode climate. Because climate and biotic interactions covary, reciprocal transplants and climate gradient studies should consider soil biotic interactions and abiotic conditions when evaluating climate change effects on plant performance.

  13. Responses of Soybean Mutant Lines to Aluminium under In Vitro and In Vivo Condition

    International Nuclear Information System (INIS)

    Yuliasti; Sudarsono

    2011-01-01

    The main limited factors of soybean plants expansion in acid soil are Aluminium (Al) toxicity and low pH. The best approach to solve this problem is by using Al tolerance variety. In vitro or in vivo selections using selective media containing AlCl 3 and induced callus embryonic of mutant lines are reliable methods to develop a new variety. The objectives of this research are to evaluate response of soybean genotypes against AlCl 3 under in vitro and in vivo condition. Addition of 15 part per million (ppm) AlCl 3 into in vitro and in vivo media severely affected plant growth. G3 soybean mutant line was identified as more tolerant than the control soybean cultivar Tanggamus. This mutant line was able to survive under more severe AlCl 3 concentrations (15 ppm) under in vitro conditions. Under in vivo conditions, G1 and G4 mutants were also identified as more tolerant than Tanggamus since they produced more pods and higher dry seed weigh per plant. Moreover, G4 mutant line also produced more dry seed weight per plant than Tanggamus when they were grown on soil containing high Al concentration 8.1 me/100 gr = 81 ppm Al +3 . (author)

  14. Responses of Soybean Mutant Lines to Aluminium under In Vitro and In Vivo Condition

    Directory of Open Access Journals (Sweden)

    Yuliasti

    2011-12-01

    Full Text Available The main limited factors of soybean plants expansion in acid soil are Aluminium (Al toxicity and low pH. The best approach to solve this problem is by using Al tolerance variety. In vitro or in vivo selections using selective media containing AlCl3 and induced callus embryonic of mutant lines are reliable methods to develop a new variety. The objectives of this research are to evaluate response of soybean genotypes against AlCl3 under in vitro and in vivo condition. Addition of 15 part per million (ppm AlCl3 into in vitro and in vivo media severely affected plant growth. G3 soybean mutant line was identified as more tolerant than the control soybean cultivar Tanggamus. This mutant line was able to survive under more severe AlCl3 concentrations (15 ppm under in vitro conditions. Under in vivo conditions, G1 and G4 mutants were also identified as more tolerant than Tanggamus since they produced more pods and higher dry seed weigh per plant. Moreover, G4 mutant line also produced more dry seed weight per plant than Tanggamus when they were grown on soil containing high Al concentration 8.1 me/100gr = 81 ppm. Al+3

  15. Unique phytochrome responses of the holoparasitic plant Orobanche minor.

    Science.gov (United States)

    Takagi, Kazuteru; Okazawa, Atsushi; Wada, Yu; Mongkolchaiyaphruek, Anchaya; Fukusaki, Eiichiro; Yoneyama, Koichi; Takeuchi, Yasutomo; Kobayashi, Akio

    2009-06-01

    Holoparasitic plants such as Orobanche spp. have lost their photosynthetic ability, so photoresponses to optimize photosynthesis are not necessary in these plants. Photoresponses are also involved in the regulation of plant development but the photoresponses of holoparasites have not been characterized in detail. In this study, the phytochrome (phy)-related photoresponse of Orobanche minor was investigated. Its photoreceptor, phytochrome A (OmphyA), was also characterized. Light effects on germination, shoot elongation, anthocyanin biosynthesis, and OmphyA expression and subcellular localization were analyzed. Red light (R):far-red light (FR) reversible inhibition of O. minor seed germination demonstrated that phy-mediated responses are retained in this holoparasite. Shoot elongation was inhibited by FR but not by R. This pattern is unique among known patterns of plant photoresponses. Additionally, molecular analysis showed that OmphyA is able to respond to the light signals. Interestingly, the unique pattern of photoresponses in O. minor seems to have been modified for adaptation to its parasitic life cycle. We hypothesize that this alteration has resulted from the loss or alteration of some phy-signaling components. Elucidation of altered components in phy signaling in this parasite will provide useful information not only about its physiological characteristics but also about general plant photoreception systems.

  16. Unearthing Bacillus endophytes from desert plants that enhance growth of Arabidopsis thaliana under abiotic stress conditions

    KAUST Repository

    Bokhari, Ameerah M

    2018-04-01

    Here, we embarked a bioprospecting project that focuses on the isolation and characterization of plant root endophytes, collected from the Thar Desert. A total of 381 endophytes were isolated and based on their 16S rRNA gene sequences, genus Bacillus (58 strains) was identified as the major taxon and only endophytes from this genus were isolated from all plant types. Of the 58 Bacillus strains, only 16 strains were selected for screening of plant growth promotion traits such as P and Zn solubilization, indole-3-acetic acid and siderophore production, and antimicrobial activity. Based on the presence of specific plant growth promotion traits 10 strains were shortlisted for further in vitro screening with A. thaliana; to confirm that these bacteria can confer resilience to plants under salt stress conditions. B. circulans (PK3-15 and PK3-109), B. cereus (PK6-15) B. subtilis (PK3-9) and B. licheniformis (PK5-26) displayed the ability to increased the fresh weight of A. thaliana under salt stress conditions by more than 50 % compared to the uninoculated control. An interesting observation was that B. circulans (PK3-109) (shown to produce IAA exopolysaccharide) and B. circulans (PK3-138) (shown to produce IAA) in vitro results were substantially different as B. circulans (PK3-138) decreased the total fresh weight of A. thaliana by 47 %, whilst B. circulans (PK3-109) was one of the best performing strains. Thus, the genomes of these two strains were sequences to unravel the molecular versatility of B. circulans strains, specifically with respect to their interaction with plants. Most of the genome of these strains is identical but the most interesting feature was the presence of 1/ the DegS–DegU two-component system that is known to mediate the salt stress response and DegU also represses toxin wapA similar to antitoxin wapI, and 2/ YxiG, a gene in the unique orthogroup of PK3-109 was found to be linked to WapI. Thus, PK3-138 substantially decreasing the total fresh

  17. The Venturia Apple Pathosystem: Pathogenicity Mechanisms and Plant Defense Responses

    Directory of Open Access Journals (Sweden)

    Gopaljee Jha

    2009-01-01

    Full Text Available Venturia inaequalis is the causal agent of apple scab, a devastating disease of apple. We outline several unique features of this pathogen which are useful for molecular genetics studies intended to understand plant-pathogen interactions. The pathogenicity mechanisms of the pathogen and overview of apple defense responses, monogenic and polygenic resistance, and their utilization in scab resistance breeding programs are also reviewed.

  18. Grazing responses in herbs in relation to herbivore selectivity and plant traits in an alpine ecosystem.

    Science.gov (United States)

    Evju, Marianne; Austrheim, Gunnar; Halvorsen, Rune; Mysterud, Atle

    2009-08-01

    Herbivores shape plant communities through selective foraging. However, both herbivore selectivity and the plant's ability to tolerate or resist herbivory may depend on the density of herbivores. In an alpine ecosystem with a long history of grazing, plants are expected to respond to both enhanced and reduced grazing pressures, and the interaction between plant traits and changes in species abundance are expected to differ between the two types of alteration of grazing regime. To understand the mechanisms behind species response, we investigated the relationship between sheep selectivity (measured in situ), plant traits and experimentally derived measures of change in species abundance as a response to the enhancement (from low to high density) or cessation (from low to zero density) of sheep grazing pressure over a six-year time period for 22 abundant herb species in an alpine habitat in south Norway. Sheep selected large, late-flowering herbs with a low leaf C/N ratio. Species that increased in abundance in response to enhanced grazing pressure were generally small and had high root/shoot ratios, thus exhibiting traits that reflect both resistance (through avoidance) and tolerance (through regrowth capacity) strategies. The abundance of selected species remained stable during the study period, and also under the enhanced grazing pressure treatment. There was, however, a tendency for selected species to respond positively to cessation of grazing, although overall responses to cessation of grazing were much less pronounced than responses to enhanced grazing. Avoidance through short stature (probably associated with increased light availability through the removal of tall competitors) as well as a certain amount of regrowth capacity appear to be the main mechanisms behind a positive response to enhanced grazing pressure in this study. The plant trait perspective clearly improves our insight into the mechanisms behind observed changes in species abundance when the

  19. Stimuli-Responsive Polymer-Clay Nanocomposites under Electric Fields

    OpenAIRE

    Piao, Shang Hao; Kwon, Seung Hyuk; Choi, Hyoung Jin

    2016-01-01

    This short Feature Article reviews electric stimuli-responsive polymer/clay nanocomposites with respect to their fabrication, physical characteristics and electrorheological (ER) behaviors under applied electric fields when dispersed in oil. Their structural characteristics, morphological features and thermal degradation behavior were examined by X-ray diffraction pattern, scanning electron microscopy and transmission electron microscopy, and thermogravimetric analysis, respectively. Particul...

  20. Reciprocal Regulation of the TOR Kinase and ABA Receptor Balances Plant Growth and Stress Response.

    Science.gov (United States)

    Wang, Pengcheng; Zhao, Yang; Li, Zhongpeng; Hsu, Chuan-Chih; Liu, Xue; Fu, Liwen; Hou, Yueh-Ju; Du, Yanyan; Xie, Shaojun; Zhang, Chunguang; Gao, Jinghui; Cao, Minjie; Huang, Xiaosan; Zhu, Yingfang; Tang, Kai; Wang, Xingang; Tao, W Andy; Xiong, Yan; Zhu, Jian-Kang

    2018-01-04

    As sessile organisms, plants must adapt to variations in the environment. Environmental stress triggers various responses, including growth inhibition, mediated by the plant hormone abscisic acid (ABA). The mechanisms that integrate stress responses with growth are poorly understood. Here, we discovered that the Target of Rapamycin (TOR) kinase phosphorylates PYL ABA receptors at a conserved serine residue to prevent activation of the stress response in unstressed plants. This phosphorylation disrupts PYL association with ABA and with PP2C phosphatase effectors, leading to inactivation of SnRK2 kinases. Under stress, ABA-activated SnRK2s phosphorylate Raptor, a component of the TOR complex, triggering TOR complex dissociation and inhibition. Thus, TOR signaling represses ABA signaling and stress responses in unstressed conditions, whereas ABA signaling represses TOR signaling and growth during times of stress. Plants utilize this conserved phospho-regulatory feedback mechanism to optimize the balance of growth and stress responses. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Molecular mechanisms governing differential robustness of development and environmental responses in plants.

    Science.gov (United States)

    Lachowiec, Jennifer; Queitsch, Christine; Kliebenstein, Daniel J

    2016-04-01

    Robustness to genetic and environmental perturbation is a salient feature of multicellular organisms. Loss of developmental robustness can lead to severe phenotypic defects and fitness loss. However, perfect robustness, i.e. no variation at all, is evolutionarily unfit as organisms must be able to change phenotype to properly respond to changing environments and biotic challenges. Plasticity is the ability to adjust phenotypes predictably in response to specific environmental stimuli, which can be considered a transient shift allowing an organism to move from one robust phenotypic state to another. Plants, as sessile organisms that undergo continuous development, are particularly dependent on an exquisite fine-tuning of the processes that balance robustness and plasticity to maximize fitness. This paper reviews recently identified mechanisms, both systems-level and molecular, that modulate robustness, and discusses their implications for the optimization of plant fitness. Robustness in living systems arises from the structure of genetic networks, the specific molecular functions of the underlying genes, and their interactions. This very same network responsible for the robustness of specific developmental states also has to be built such that it enables plastic yet robust shifts in response to environmental changes. In plants, the interactions and functions of signal transduction pathways activated by phytohormones and the tendency for plants to tolerate whole-genome duplications, tandem gene duplication and hybridization are emerging as major regulators of robustness in development. Despite their obvious implications for plant evolution and plant breeding, the mechanistic underpinnings by which plants modulate precise levels of robustness, plasticity and evolvability in networks controlling different phenotypes are under-studied. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions

  2. Response of plants to high concentrations of uranium stress and the screening of remediation plants

    International Nuclear Information System (INIS)

    Tang Yongjin; Luo Xuegang; Zeng Feng; Jiang Shijie

    2013-01-01

    Studies of the resistance and accumulation ability of different plant species to uranium (U) has important influence on the bioremediation of U contaminated soil. The resistance and enrichment ability of high concentrations of U (500 mg · kg -1 soil) in fourteen plant species were investigated and evaluated in this study in order to screen remediation plants for governance soil U contamination. The results showed that: (1) high concentrations of U stress had different effects on the emergence and survival of the different plants. The seed emergence of Hibiscus esculentus was reduced by 2/3, but the seed emergence of Gynura cusimbua (D. Don) S. Moore, Chenopodium album L. and Phaseolus vulgaris var. humilis Alef were not reduced. Under the contaminated soil, all the sesamum indicum died within a month after the emergence and the survival number of Amaranth and Iresine herbstii 'Aureo-reticulata' reduced by about 80%. But the survival number of Alternanthera philoxeroides (Mart.) Griseb., Chenopodium album L. and Phaseolus vulgaris var. humilis Alef were not influenced. (2) The biomass of the plants would be reduced by 8-99% in the uranium-contaminated soil. The anti-stress ability of Phaseolus vulgaris var. humilis Alef was the strongest in the fourteen plants, and Cucurbita pepo L., Sorghumbicolor (L.) Moench, Ipomoea aquatica Forsk, Helianthus annuus, Chenopodium album L. and Alternanthera philoxeroides (Mart.) Griseb. showed some the anti-stress ability. (3) Significant differences were found in the capacity of plants to absorb uranium between under high-uranium contaminated soil and under the non-uranium contaminated soil were. The plants with higher uranium content in thenon-contaminated soil were Gomphrena globosa, and Cucurbita pepo L., which were 2.249 mg · kg -1 DW and 1.620 mg · kg -1 DW, respectively. But the plants with higher uranium content in the high uranium contaminated soil were Cichorium intybus L., Amaranth and Ipomoea aquatica Forsk

  3. High-Arctic Plant-Herbivore Interactions under Climate Influence

    DEFF Research Database (Denmark)

    Berg, Thomas B.; Schmidt, Niels M.; Høye, Toke Thomas

    This chapter focuses on a 10-year data series from Zackenberg on the trophic interactions between two characteristic arctic plant species, arctic willow Salix arctica and mountain avens Dryas octopetala, and three herbivore species covering the very scale of size present at Zackenberg, namely...... production upon which the herbivores depend, and snow may be the most important climatic factor affecting the different trophic levels and the interactions between them. Hence, the spatio-temporal distribution of snow, as well as thawing events during winter, may have considerable effects on the herbivores...... indirectly, influenced the spatial distribution of herbivores. Additionally, snow distribution directly affected the distribution of herbivores, and hence, in turn, affected the plant community by selective feeding and locally reducing the standing biomass of forage plants. Although only few moth larvae were...

  4. INITIAL DEVELOPMENT OF AÇAÍ PLANTS UNDER SHADE GRADATION

    Directory of Open Access Journals (Sweden)

    ELEANDRO CANDIDO DAPONT

    2016-01-01

    Full Text Available ABSTRACT In order to evaluate the effect of different levels of shading on açai (Euterpe oleracea Mart. plants development, an experiment was conducted at the nursery of Floresta, Rio Branco, AC. The experiment was arranged in a completely randomized design with six treatments and four replications of 25 plants, set as full sunlight and 18%, 35%, 50%, 70%, and 80% shading. The evaluation occurred 125 days after transplantation and the variables were stem diameter, root length, length of the aerial part, total length, dry matter of root, dry matter of aerial part, and total dry matter. With exception of root length, there was significant difference between treatments for all variables. The production of açai plants should be performed using 40% shading.

  5. Optimization of diagnostic microarray for application in analysing landfill methanotroph communities under different plant covers.

    Science.gov (United States)

    Stralis-Pavese, Nancy; Sessitsch, Angela; Weilharter, Alexandra; Reichenauer, Thomas; Riesing, Johann; Csontos, József; Murrell, J Colin; Bodrossy, Levente

    2004-04-01

    Landfill sites are responsible for 6-12% of global methane emission. Methanotrophs play a very important role in decreasing landfill site methane emissions. We investigated the methane oxidation capacity and methanotroph diversity in lysimeters simulating landfill sites with different plant vegetations. Methane oxidation rates were 35 g methane m-2 day-1 or higher for planted lysimeters and 18 g methane m-2 day-1 or less for bare soil controls. Best methane oxidation, as displayed by gas depth profiles, was found under a vegetation of grass and alfalfa. Methanotroph communities were analysed at high throughput and resolution using a microbial diagnostic microarray targeting the particulate methane monooxygenase (pmoA) gene of methanotrophs and functionally related bacteria. Members of the genera Methylocystis and Methylocaldum were found to be the dominant members in landfill site simulating lysimeters. Soil bacterial communities in biogas free control lysimeters, which were less abundant in methanotrophs, were dominated by Methylocaldum. Type Ia methanotrophs were found only in the top layers of bare soil lysimeters with relatively high oxygen and low methane concentrations. A competetive advantage of type II methanotrophs over type Ia methanotrophs was indicated under all plant covers investigated. Analysis of average and individual results from parallel samples was used to identify general trends and variations in methanotroph community structures in relation to depth, methane supply and plant cover. The applicability of the technology for the detection of environmental perturbations was proven by an erroneous result, where an unexpected community composition detected with the microarray indicated a potential gas leakage in the lysimeter being investigated.

  6. Evaluation of Yield and Yield Components of Black Cumin (Nigella sativa L. under different Plant Density and Limited Irrigation Condition

    Directory of Open Access Journals (Sweden)

    Sh Rezvan Beidokhti

    2012-10-01

    Full Text Available Research on crop response to deficit irrigation is important to reduce agriculture water use in areas where water is limited resource. Using drought resistant landraces with irrigation scheduling based on phenological stages in semi-arid and arid regions may provide an opportunity to optimize irrigation efficiency and water savings in these regions. In order to evaluate of yield and yield components of black cumin under different plant density and limited irrigation condition an experiment was conducted in Research Farm of Islamic Azad University of Damghan during growing season of 2007-2008. The experimental treatments were arranged in split plots based on a complete randomized block design with three replications. The limited irrigation (based on phenological stages treatments were included: cutting irrigation at blooming (folded flowers, cutting irrigation at flowering stage, cutting irrigation at seed formation and normal weekly irrigation (control were allocated to the main plots and different plant density: 100, 150, 200 and 250 plant per square meter (m2 were allocated to sub plots. The results showed that the effect of limited irrigation, plant density and their interaction on plant height, number of follicle, follicle weight, number of seed, 1000 seed weight, seed yield, biological yield and harvest index Black Cumin. The highest yield and yield components was obtained in normal irrigation (control and 200 plant density and the lowest yield were obtained when irrigation cut at the blooming stage and 250 plant density. There was a significant correlation between seed yield and number (r=0.90, 1000 seed weight (r=0.95 and biological yield (r=0.97. Optimum plant density of black cumin was decreased under limited irrigation treatments. Under normal (control and limited irrigation, optimum plant density was 200 and 150 plant per (m2 respectively.

  7. Hexanoic acid protects tomato plants against Botrytis cinerea by priming defence responses and reducing oxidative stress.

    Science.gov (United States)

    Finiti, Ivan; de la O Leyva, María; Vicedo, Begonya; Gómez-Pastor, Rocío; López-Cruz, Jaime; García-Agustín, Pilar; Real, Maria Dolores; González-Bosch, Carmen

    2014-08-01

    Treatment with the resistance priming inducer hexanoic acid (Hx) protects tomato plants from Botrytis cinerea by activating defence responses. To investigate the molecular mechanisms underlying hexanoic acid-induced resistance (Hx-IR), we compared the expression profiles of three different conditions: Botrytis-infected plants (Inf), Hx-treated plants (Hx) and Hx-treated + infected plants (Hx+Inf). The microarray analysis at 24 h post-inoculation showed that Hx and Hx+Inf plants exhibited the differential expression and priming of many Botrytis-induced genes. Interestingly, we found that the activation by Hx of other genes was not altered by the fungus at this time point. These genes may be considered to be specific targets of the Hx priming effect and may help to elucidate its mechanisms of action. It is noteworthy that, in Hx and Hx+Inf plants, there was up-regulation of proteinase inhibitor genes, DNA-binding factors, enzymes involved in plant hormone signalling and synthesis, and, remarkably, the genes involved in oxidative stress. Given the relevance of the oxidative burst occurring in plant-pathogen interactions, the effect of Hx on this process was studied in depth. We showed by specific staining that reactive oxygen species (ROS) accumulation in Hx+Inf plants was reduced and more restricted around infection sites. In addition, these plants showed higher ratios of reduced to oxidized glutathione and ascorbate, and normal levels of antioxidant activities. The results obtained indicate that Hx protects tomato plants from B. cinerea by regulating and priming Botrytis-specific and non-specific genes, preventing the harmful effects of oxidative stress produced by infection. © 2013 BSPP AND JOHN WILEY & SONS LTD.

  8. Neonicotinoid insecticides induce salicylate-associated plant defense responses

    Science.gov (United States)

    Ford, Kevin A.; Casida, John E.; Chandran, Divya; Gulevich, Alexander G.; Okrent, Rachel A.; Durkin, Kathleen A.; Sarpong, Richmond; Bunnelle, Eric M.; Wildermuth, Mary C.

    2010-01-01

    Neonicotinoid insecticides control crop pests based on their action as agonists at the insect nicotinic acetylcholine receptor, which accepts chloropyridinyl- and chlorothiazolyl-analogs almost equally well. In some cases, these compounds have also been reported to enhance plant vigor and (a)biotic stress tolerance, independent of their insecticidal function. However, this mode of action has not been defined. Using Arabidopsis thaliana, we show that the neonicotinoid compounds, imidacloprid (IMI) and clothianidin (CLO), via their 6-chloropyridinyl-3-carboxylic acid and 2-chlorothiazolyl-5-carboxylic acid metabolites, respectively, induce salicylic acid (SA)-associated plant responses. SA is a phytohormone best known for its role in plant defense against pathogens and as an inducer of systemic acquired resistance; however, it can also modulate abiotic stress responses. These neonicotinoids effect a similar global transcriptional response to that of SA, including genes involved in (a)biotic stress response. Furthermore, similar to SA, IMI and CLO induce systemic acquired resistance, resulting in reduced growth of a powdery mildew pathogen. The action of CLO induces the endogenous synthesis of SA via the SA biosynthetic enzyme ICS1, with ICS1 required for CLO-induced accumulation of SA, expression of the SA marker PR1, and fully enhanced resistance to powdery mildew. In contrast, the action of IMI does not induce endogenous synthesis of SA. Instead, IMI is further bioactivated to 6-chloro-2-hydroxypyridinyl-3-carboxylic acid, which is shown here to be a potent inducer of PR1 and inhibitor of SA-sensitive enzymes. Thus, via different mechanisms, these chloropyridinyl- and chlorothiazolyl-neonicotinoids induce SA responses associated with enhanced stress tolerance. PMID:20876120

  9. Leaf anatomy of genotypes of banana plant grown under coloured ...

    African Journals Online (AJOL)

    SAM

    2014-06-04

    Jun 4, 2014 ... contributes to improving the adaptability of plants in different environments (Silva and Nogueira, 2012). The use of coloured shade nets is a way to modify the natural radiation providing an increase in the amount of diffuse light, by combining physical protection with differential refraction of the solar radiation ...

  10. Relationships between Plant Biomass and Species Richness under ...

    African Journals Online (AJOL)

    The study was conducted in a montane grassland of Kokosa District, West Arsi Zone of Oromia Region, southern Ethiopia. The objective of the study was to investigate the relationships between aboveground plant biomass and species richness in three farming systems and four grazing management systems. A total of 180 ...

  11. Application of optical controlling methods for plants under external influence

    Science.gov (United States)

    Timchenko, E. V.; Taskina, L. A.

    2012-10-01

    The experimental study results of spectral characteristic change of different types of plants influenced by external factors (synthetic superficially active substances, salts of heavy metals and nitrate fertilizers) are presented. Differential optical factor was used as the monitored optical parameter that characterizes the chlorophyll concentration change. The differential backscatter method which has high test-sensitivity and provides with the most complete information on the plant condition was the main optical monitoring method. For understanding the mechanisms of external factor accumulation and influence on plants the confocal fluorescent microscopy method providing contrast micrographs of high resolution was used for microscopic analysis in the study. It was revealed that synthetic superficially active substances and heavy metal presence lead to quasilinear decrease of differential backscatter factor with time. It was shown that the presence of salts of heavy metals in a water solution leads to chlorophyll "binding" which is microscopically shown as their «adhesion» near the cell membranes. On the contrary, the presence of synthetic superficially active substances maintains the uniformity of chlorophyll distribution in a cell, but its concentration falls with increasing the concentration in a major emission. The latter depends on the fact that synthetic superficially active substances solubilize the cell membrane proteins, increasing its penetrability. It causes pigment release ("washing away") from a plant, thereby leading to differential optical factor change. It was shown that nitrate fertilizer presence leads to increase of differential backscatter factor with time which is microscopically connected to increase in chlorophyll concentration.

  12. Investment decisions under uncertainties : A case of nuclear power plants

    NARCIS (Netherlands)

    Jain, S.

    2014-01-01

    This thesis discusses the role of flexibility of decisions when investing in projects that are affected by economic uncertainties. It uses the theory of real options to value such investment decisions. The thesis focuses on investment decisions related to nuclear power plants, which usually are

  13. A Meta-analysis of Plant Photosynthetic Traits and Water-use efficiency Responses to Drought

    Science.gov (United States)

    Zhang, J.

    2017-12-01

    Drought is predicted to become more intense and frequent in many regions of the world in the context of climate change, especially in the semi-arid regions of the Northern Hemisphere. Understanding the plant photosynthetic traits (Pn, Gs and Tr) and water use efficiency (WUE) response to drought is very important with regard to plant growth and productivity, which could reflect the terrestrial primary productivity worldwide. We used a meta-analysis based on studies of a worldwide range and full plant species Pn, Gs, Tr and WUE under drought condition and aimed to determine the responses of Pn, Gs, Tr and WUE of different drought intensities (mild, moderate and severe), different photosynthetic pathways (C3 and C4) and growth forms (herbs, shrubs, trees and lianas). Furthermore, reveal the differences from different plant groups (e.g. C3 and C4 plants; annual (A-herbs) and perennial (P-herbs) herbs; conifer, deciduous and evergreen trees) under the same drought intensities. Additionally, we analyzed the relationship between stomatal conductance (Gs) with Pn, Tr and WUE. Our results were as follows: 1) drought decreased the photosynthetic traits with the drought stress increasing, but increased the water use efficiency, and increased to the greatest extent in lianas, compared with herbs, shrubs and trees. 2) Furthermore, C4 plants had an advantage in photosynthesis compared to C3 plants under the same drought conditions. However, the WUE in C4 plants was not promoted as in C3 plants. The photosynthesis traits showed a more substantial decrease in P-herbs than in A-herbs. The drought promoted the WUE in P-herbs, but inhibited it in A-herbs. Compared with conifer and deciduous trees, the photosynthesis traits declined the most in evergreen tree. The WUE in deciduous trees showed a more obvious increase among the three leaf habits. 3) Finally, the Gs showed a close relationship with photosynthesis rate (Pn) and transpiration rate (Tr), which could explain 50% of the

  14. Root system size of alfalfa varieties under different plant densities

    Directory of Open Access Journals (Sweden)

    Esmail Al-Mosanif

    2012-01-01

    Full Text Available The field experiment was established from pre-grown alfalfa sprouts in 2008. In 2009 and 2010, the harvest was carried out. The yield and the root size system (RSS were evaluated in the total of five cuts. Two localities of diverse soil and weather conditions were selected. Žabčice is a dry location with a highly permeable sandy soil layer, but at the same time, with a considerable fluctuation of the underground water level; Troubsko, on the other hand, represented a location with a higher content of clay in soil suitable for growing alfalfa. The trial was established in two types of plant spacing – 25 × 25 cm (16 plants per m2 and 50 × 50 cm (4 plants per m2. Two alfalfa varieties were used – Hodonínka (an old variety and Oslava (a new variety. The following factors were evaluated by statistical means: location, variety, plant spacing, and cut number. The effect of location on the above ground phytomass and the RSS value proved highly statistically decisive. The higher average values of above ground phytomass as well as RSS were achieved on the Troubsko location where the above ground phytomass was 19.57 t.ha−1 and RSS was 2.71 nanofarad (nF. The impact of the variety was highly statistically significant only in respect to RSS. The effect of variety on the alfalfa above ground phytomass was not proven. The higher average RSS values were reached by the Hodonínka variety (2.59 nF. The effect of the plant spacing on both the above ground phytomass and the RSS values was highly statistically significant. The higher average above ground phytomass was achieved when the 25 × 25 cm plant spacing was employed (18.64 t.ha−1. As for the RSS value, the case was exactly opposite – the higher average value was reached when the plant spacing was 50 × 50 cm (2.99 nF. The impact of the cut number on both the above ground phytomass and the RSS was highly statistically significant. The highest average above ground phytomass and root

  15. The transcription factor IDEF1 regulates the response to and tolerance of iron deficiency in plants.

    Science.gov (United States)

    Kobayashi, Takanori; Ogo, Yuko; Itai, Reiko Nakanishi; Nakanishi, Hiromi; Takahashi, Michiko; Mori, Satoshi; Nishizawa, Naoko K

    2007-11-27

    Iron is essential for most living organisms and is often the major limiting nutrient for normal growth. Plants induce iron utilization systems under conditions of low iron availability, but the molecular mechanisms of gene regulation under iron deficiency remain largely unknown. We identified the rice transcription factor IDEF1, which specifically binds the iron deficiency-responsive cis-acting element IDE1. IDEF1 belongs to an uncharacterized branch of the plant-specific transcription factor family ABI3/VP1 and exhibits the sequence recognition property of efficiently binding to the CATGC sequence within IDE1. IDEF1 transcripts are constitutively present in rice roots and leaves. Transgenic tobacco plants expressing IDEF1 under the control of the constitutive cauliflower mosaic virus 35S promoter transactivate IDE1-mediated expression only in iron-deficient roots. Transgenic rice plants expressing an introduced IDEF1 exhibit substantial tolerance to iron deficiency in both hydroponic culture and calcareous soil. IDEF1 overexpression leads to the enhanced expression of the iron deficiency-induced transcription factor gene OsIRO2, suggesting the presence of a sequential gene regulatory network. These findings reveal cis element/trans factor interactions that are functionally linked to the iron deficiency response. Manipulation of IDEF1 also provides another approach for producing crops tolerant of iron deficiency to enhance food and biomass production in calcareous soils.

  16. How light competition between plants affects their response to climate change.

    Science.gov (United States)

    van Loon, Marloes P; Schieving, Feike; Rietkerk, Max; Dekker, Stefan C; Sterck, Frank; Anten, Niels P R

    2014-09-01

    How plants respond to climate change is of major concern, as plants will strongly impact future ecosystem functioning, food production and climate. Here, we investigated how vegetation structure and functioning may be influenced by predicted increases in annual temperatures and atmospheric CO2 concentration, and modeled the extent to which local plant-plant interactions may modify these effects. A canopy model was developed, which calculates photosynthesis as a function of light, nitrogen, temperature, CO2 and water availability, and considers different degrees of light competition between neighboring plants through canopy mixing; soybean (Glycine max) was used as a reference system. The model predicts increased net photosynthesis and reduced stomatal conductance and transpiration under atmospheric CO2 increase. When CO2 elevation is combined with warming, photosynthesis is increased more, but transpiration is reduced less. Intriguingly, when competition is considered, the optimal response shifts to producing larger leaf areas, but with lower stomatal conductance and associated vegetation transpiration than when competition is not considered. Furthermore, only when competition is considered are the predicted effects of elevated CO2 on leaf area index (LAI) well within the range of observed effects obtained by Free air CO2 enrichment (FACE) experiments. Together, our results illustrate how competition between plants may modify vegetation responses to climate change. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  17. Site-specific earthquake response analysis for Paducah Gaseous Diffusion Plant, Paducah, Kentucky. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Sykora, D.W.; Davis, J.J.

    1993-08-01

    The Paducah Gaseous Diffusion Plant (PGDP), owned by the US Department of Energy (DOE) and operated under contract by Martin Marietta Energy systems, Inc., is located southwest of Paducah, Kentucky. An aerial photograph and an oblique sketch of the plant are shown in Figures 1 and 2, respectively. The fenced portion of the plant consists of 748 acres. This plant was constructed in the 1950`s and is one of only two gaseous diffusion plants in operation in the United States; the other is located near Portsmouth, Ohio. The facilities at PGDP are currently being evaluated for safety in response to natural seismic hazards. Design and evaluation guidelines to evaluate the effects of earthquakes and other natural hazards on DOE facilities follow probabilistic hazard models that have been outlined by Kennedy et al. (1990). Criteria also established by Kennedy et al. (1990) classify diffusion plants as ``moderate hazard`` facilities. The US Army Engineer Waterways Experiment Station (WES) was tasked to calculate the site response using site-specific design earthquake records developed by others and the results of previous geotechnical investigations. In all, six earthquake records at three hazard levels and four individual and one average soil columns were used.

  18. How a retrotransposon exploits the plant's heat stress response for its activation.

    Directory of Open Access Journals (Sweden)

    Vladimir V Cavrak

    2014-01-01

    Full Text Available Retrotransposons are major components of plant and animal genomes. They amplify by reverse transcription and reintegration into the host genome but their activity is usually epigenetically silenced. In plants, genomic copies of retrotransposons are typically associated with repressive chromatin modifications installed and maintained by RNA-directed DNA methylation. To escape this tight control, retrotransposons employ various strategies to avoid epigenetic silencing. Here we describe the mechanism developed by ONSEN, an LTR-copia type retrotransposon in Arabidopsis thaliana. ONSEN has acquired a heat-responsive element recognized by plant-derived heat stress defense factors, resulting in transcription and production of full length extrachromosomal DNA under elevated temperatures. Further, the ONSEN promoter is free of CG and CHG sites, and the reduction of DNA methylation at the CHH sites is not sufficient to activate the element. Since dividing cells have a more pronounced heat response, the extrachromosomal ONSEN DNA, capable of reintegrating into the genome, accumulates preferentially in the meristematic tissue of the shoot. The recruitment of a major plant heat shock transcription factor in periods of heat stress exploits the plant's heat stress response to achieve the transposon's activation, making it impossible for the host to respond appropriately to stress without losing control over the invader.

  19. Carbon and nitrogen metabolism in arbuscular mycorrhizal maize plants under low-temperature stress

    DEFF Research Database (Denmark)

    Zhu, Xian-Can; Song, Feng-Bin; Liu, Fulai

    2015-01-01

    Effects of the arbuscular mycorrhizal (AM) fungus Glomus tortuosum on carbon (C) and nitrogen (N) metabolism of Zea mays L. grown under low-temperature stress was investigated. Maize plants inoculated or not inoculated with AM fungus were grown in a growth chamber at 258C for 4 weeks...... plants were higher than those of non-AM plants. AM plants had a higher net photosynthetic rate (Pn) than non-AM plants, although low temperature inhibited the Pn. Compared with non-AM plants, AM plants exhibited higher leaf soluble sugars, reducing sugars, root sucrose and fructose contents, and sucrose...... phosphate synthase and amylase activities at low temperature. Moreover, low-temperature stress increased theC :Nratio in the leaves of maize plants, and AM colonisation decreased the root C :N ratio. These results suggested a difference in the C and N metabolism of maize plants at ambient and low...

  20. Role of Ethylene and Its Cross Talk with Other Signaling Molecules in Plant Responses to Heavy Metal Stress1

    Science.gov (United States)

    Thao, Nguyen Phuong; Khan, M. Iqbal R.; Thu, Nguyen Binh Anh; Hoang, Xuan Lan Thi; Asgher, Mohd; Khan, Nafees A.; Tran, Lam-Son Phan

    2015-01-01

    Excessive heavy metals (HMs) in agricultural lands cause toxicities to plants, resulting in declines in crop productivity. Recent advances in ethylene biology research have established that ethylene is not only responsible for many important physiological activities in plants but also plays a pivotal role in HM stress tolerance. The manipulation of ethylene in plants to cope with HM stress through various approaches targeting either ethylene biosynthesis or the ethylene signaling pathway has brought promising outcomes. This review covers ethylene production and signal transduction in plant responses to HM stress, cross talk between ethylene and other signaling molecules under adverse HM stress conditions, and approaches to modify ethylene action to improve HM tolerance. From our current understanding about ethylene and its regulatory activities, it is believed that the optimization of endogenous ethylene levels in plants under HM stress would pave the way for developing transgenic crops with improved HM tolerance. PMID:26246451

  1. Physiological characteristics of high yield under cluster planting: photosynthesis and canopy microclimate of cotton

    Directory of Open Access Journals (Sweden)

    Ting-ting Xie

    2016-01-01

    Full Text Available Cotton produces more biomass and economic yield when cluster planting pattern (three plants per hole than in a traditional planting pattern (one plant per hole, even at similar plant densities, indicating that individual plant growth is promoted by cluster planting. The causal factors for this improved growth induced by cluster planting pattern, the light interception, canopy microclimate and photosynthetic rate of cotton were investigated in an arid region of China. The results indicated that the leaf area index and light interception were higher in cluster planting, and significantly different from those in traditional planting during the middle and late growth stages. Cotton canopy humidity at different growth stages was increased but canopy temperatures were reduced by cluster planting. In the later growth stage of cluster planting, the leaf chlorophyll content was higher and the leaf net photosynthetic rate and canopy photosynthetic rate were significantly increased in comparing with traditional planting pattern. We concluded that differences in canopy light interception and photosynthetic rate were the primary factors responsible for increased biomass production and economic yield in cluster planting compared with the traditional planting of cotton.

  2. Response of Magnetic Force Microscopy Probes under AC Magnetic Field

    Science.gov (United States)

    Sungthong, A.; Ruksasakchai, P.; Saengkaew, K.; Cheowanish, I.; Damrongsak, B.

    2017-09-01

    In this paper, magnetic force microscopy (MFM) probes with different coating materials were characterized under AC magnetic field. A perpendicular magnetic write head similar to those used in hard disk drives was employed as the AC magnetic field generator. In order to measure a response of MFM probes to AC magnetic field, a MFM probe under test was scanned, at a scan height of 10 nm, across the surface of the magnetic write head. During MFM imaging, the write head was biased by a sufficient magnitude of AC current, approximately 30 mA. A spectral analysis for a frequency sweep from 1 kHz to 100 MHz was extracted from post-processing MFM images. As expected, a MFM probe coated with hard magnetic alloys, i.e. FePt, has the lowest response to AC magnetic fields. MFM probes coated with soft magnetic alloys, i.e. NiFe and NiCoCr, have a relatively high and flat response across the frequency range. Ni coated MFM probe has the highest response to AC magnetic fields. In addition, CoCr and NiCo coated MFM probes show lower response than NiFe and NiCoCr probes at low frequencies; however, theirs response to AC magnetic field increase for the AC magnetic field with a frequency above 50 kHz. This can be implied that those MFM probes are a good candidate for being used to study the high-frequency performance of perpendicular magnetic write heads. Noting that response of all MFM probes significantly decreased when driven frequencies above 1 MHz due to the limitation of the hardware, i.e. response of quadrant photodiode and op-amp in a pre-amplifier.

  3. Transcriptional responses of Arabidopsis thaliana plants to As (V stress

    Directory of Open Access Journals (Sweden)

    Yuan Joshua S

    2008-08-01

    Full Text Available Abstract Background Arsenic is toxic to plants and a common environmental pollutant. There is a strong chemical similarity between arsenate [As (V] and phosphate (Pi. Whole genome oligonucleotide microarrays were employed to investigate the transcriptional responses of Arabidopsis thaliana plants to As (V stress. Results Antioxidant-related genes (i.e. coding for superoxide dismutases and peroxidases play prominent roles in response to arsenate. The microarray experiment revealed induction of chloroplast Cu/Zn superoxide dismutase (SOD (at2g28190, Cu/Zn SOD (at1g08830, as well as an SOD copper chaperone (at1g12520. On the other hand, Fe SODs were strongly repressed in response to As (V stress. Non-parametric rank product statistics were used to detect differentially expressed genes. Arsenate stress resulted in the repression of numerous genes known to be induced by phosphate starvation. These observations were confirmed with qRT-PCR and SOD activity assays. Conclusion Microarray data suggest that As (V induces genes involved in response to oxidative stress and represses transcription of genes induced by phosphate starvation. This study implicates As (V as a phosphate mimic in the cell by repressing genes normally induced when available phosphate is scarce. Most importantly, these data reveal that arsenate stress affects the expression of several genes with little or unknown biological functions, thereby providing new putative gene targets for future research.

  4. Morphological responses of plant roots to mechanical stress.

    Science.gov (United States)

    Potocka, Izabela; Szymanowska-Pulka, Joanna

    2018-02-17

    Roots are continuously exposed to mechanical pressure and this often results in their morphological modification. Most obvious are changes in the overall form of the root system as well as in the shapes of particular roots. These changes are often accompanied by modifications of the cell pattern and cell morphology. This review focuses on the morphological responses of roots to mechanical stress. Results of early and recent experiments in which roots have been exposed to mechanical pressure are assembled, analysed and discussed. Research applying different experimental sets, obstacles, media of various compactness and structure are reviewed. An effect of the combination of mechanical stresses with other abiotic stresses on roots, and results of estimating the force exerted by the roots are briefly discussed. Possible consequences of the cell pattern rearrangements are considered. Several modifications in root morphology are commonly reported: (1) decreased root size, (2) radial swelling accompanied by increased radial dimension of the cortex cell layers and (3) enhanced cap cell sloughing. Nevertheless, because of differences between species and individual plants, a universal scenario for root morphological changes resulting from externally applied pressures is not possible. Thus, knowledge of the root response to mechanical impedance remains incomplete. Studies on the mechanical properties of the root as well as on possible modifications in cell wall structure and composition as the elements responsible for the mechanical properties of the plant tissue are required to understand the response of root tissue as a biomaterial.

  5. Good and bad protons: genetic aspects of acidity stress responses in plants.

    Science.gov (United States)

    Shavrukov, Yuri; Hirai, Yoshihiko

    2016-01-01

    Physiological aspects of acidity stress in plants (synonymous with H(+) rhizotoxicity or low-pH stress) have long been a focus of research, in particular with respect to acidic soils where aluminium and H(+) rhizotoxicities often co-occur. However, toxic H(+) and Al(3+) elicit different response mechanisms in plants, and it is important to consider their effects separately. The primary aim of this review was to provide the current state of knowledge regarding the genetics of the specific reactions to low-pH stress in growing plants. A comparison of the results gleaned from quantitative trait loci analysis and global transcriptome profiling of plants in response to high proton concentrations revealed a two-stage genetic response: (i) in the short-term, proton pump H(+)-ATPases present the first barrier in root cells, allocating an excess of H(+) into either the apoplast or vacuole; the ensuing defence signaling system involves auxin, salicylic acid, and methyl jasmonate, which subsequently initiate expression of STOP and DREB transcription factors as well as chaperone ROF; (2) the long-term response includes other genes, such as alternative oxidase and type II NAD(P)H dehydrogenase, which act to detoxify dangerous reactive oxygen species in mitochondria, and help plants better manage the stress. A range of transporter genes including those for nitrate (NTR1), malate (ALMT1), and heavy metals are often up-regulated by H(+) rhizotoxicity. Expansins, cell-wall-related genes, the γ-aminobutyric acid shunt and biochemical pH-stat genes also reflect changes in cell metabolism and biochemistry in acidic conditions. However, the genetics underlying the acidity stress response of plants is complicated and only fragmentally understood. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  6. DNA Damage and Repair in Plants under Ultraviolet and Ionizing Radiations

    Science.gov (United States)

    Gill, Sarvajeet S.; Gill, Ritu; Jha, Manoranjan; Tuteja, Narendra

    2015-01-01

    Being sessile, plants are continuously exposed to DNA-damaging agents present in the environment such as ultraviolet (UV) and ionizing radiations (IR). Sunlight acts as an energy source for photosynthetic plants; hence, avoidance of UV radiations (namely, UV-A, 315–400 nm; UV-B, 280–315 nm; and UV-C, important target for UV-B induced damage. On the other hand, IR causes water radiolysis, which generates highly reactive hydroxyl radicals (OH•) and causes radiogenic damage to important cellular components. However, to maintain genomic integrity under UV/IR exposure, plants make use of several DNA repair mechanisms. In the light of recent breakthrough, the current minireview (a) introduces UV/IR and overviews UV/IR-mediated DNA damage products and (b) critically discusses the biochemistry and genetics of major pathways responsible for the repair of UV/IR-accrued DNA damage. The outcome of the discussion may be helpful in devising future research in the current context. PMID:25729769

  7. DNA Damage and Repair in Plants under Ultraviolet and Ionizing Radiations

    Directory of Open Access Journals (Sweden)

    Sarvajeet S. Gill

    2015-01-01

    Full Text Available Being sessile, plants are continuously exposed to DNA-damaging agents present in the environment such as ultraviolet (UV and ionizing radiations (IR. Sunlight acts as an energy source for photosynthetic plants; hence, avoidance of UV radiations (namely, UV-A, 315–400 nm; UV-B, 280–315 nm; and UV-C, <280 nm is unpreventable. DNA in particular strongly absorbs UV-B; therefore, it is the most important target for UV-B induced damage. On the other hand, IR causes water radiolysis, which generates highly reactive hydroxyl radicals (OH• and causes radiogenic damage to important cellular components. However, to maintain genomic integrity under UV/IR exposure, plants make use of several DNA repair mechanisms. In the light of recent breakthrough, the current minireview (a introduces UV/IR and overviews UV/IR-mediated DNA damage products and (b critically discusses the biochemistry and genetics of major pathways responsible for the repair of UV/IR-accrued DNA damage. The outcome of the discussion may be helpful in devising future research in the current context.

  8. Effect of co-existing plant specie on soil microbial activity under heavy metal stress

    International Nuclear Information System (INIS)

    Nwuche, C. O.; Ugoji, E. O.

    2010-01-01

    The influence of plant primary compounds on the activity of soil microbial communities under heavy metal stress was studied in a pot-culture field experiment conducted in a green house. Amaranthus spinosus was cultivated in an agricultural soil previously amended in the laboratory with solutions of different trace elements in two separate treatment modes: singly and in combination. Culture-independent metabolism based indices such as the rate of carbon and nitrogen mineralization, microbial biomass carbon and soil basal respiration were monitored fortnightly over a period of six weeks. Result shows that plant detritus have significant modifying effect on soil microbe-metal interactions. Data on microbial and biochemical processes in the respective mesocosms did not vary from control; not even in mesocosms containing very high concentrations of copper, zinc and nickel. The soil microbial biomass carbon and the rate of carbon and nitrogen cycling were not impeded by the respective metal treatment while the respiration responses increased as a result of increase in metabolic activity of the soil microbes. The plant based substrates enabled the soil microflora to resist high metal contamination because of its tendency to absorb large amounts of inorganic cations.

  9. Herboxidiene triggers splicing repression and abiotic stress responses in plants

    KAUST Repository

    Alshareef, Sahar

    2017-03-27

    Background Constitutive and alternative splicing of pre-mRNAs from multiexonic genes controls the diversity of the proteome; these precisely regulated processes also fine-tune responses to cues related to growth, development, and stresses. Small-molecule inhibitors that perturb splicing provide invaluable tools for use as chemical probes to uncover the molecular underpinnings of splicing regulation and as potential anticancer compounds. Results Here, we show that herboxidiene (GEX1A) inhibits both constitutive and alternative splicing. Moreover, GEX1A activates genome-wide transcriptional patterns involved in abiotic stress responses in plants. GEX1A treatment -activated ABA-inducible promoters, and led to stomatal closure. Interestingly, GEX1A and pladienolide B (PB) elicited similar cellular changes, including alterations in the patterns of transcription and splicing, suggesting that these compounds might target the same spliceosome complex in plant cells. Conclusions Our study establishes GEX1A as a potent splicing inhibitor in plants that can be used to probe the assembly, dynamics, and molecular functions of the spliceosome and to study the interplay between splicing stress and abiotic stresses, as well as having potential biotechnological applications.

  10. Stimuli-Responsive Polymer-Clay Nanocomposites under Electric Fields

    Science.gov (United States)

    Piao, Shang Hao; Kwon, Seung Hyuk; Choi, Hyoung Jin

    2016-01-01

    This short Feature Article reviews electric stimuli-responsive polymer/clay nanocomposites with respect to their fabrication, physical characteristics and electrorheological (ER) behaviors under applied electric fields when dispersed in oil. Their structural characteristics, morphological features and thermal degradation behavior were examined by X-ray diffraction pattern, scanning electron microscopy and transmission electron microscopy, and thermogravimetric analysis, respectively. Particular focus is given to the electro-responsive ER characteristics of the polymer/clay nanocomposites in terms of the yield stress and viscoelastic properties along with their applications. PMID:28787852

  11. Stimuli-Responsive Polymer-Clay Nanocomposites under Electric Fields

    Directory of Open Access Journals (Sweden)

    Shang Hao Piao

    2016-01-01

    Full Text Available This short Feature Article reviews electric stimuli-responsive polymer/clay nanocomposites with respect to their fabrication, physical characteristics and electrorheological (ER behaviors under applied electric fields when dispersed in oil. Their structural characteristics, morphological features and thermal degradation behavior were examined by X-ray diffraction pattern, scanning electron microscopy and transmission electron microscopy, and thermogravimetric analysis, respectively. Particular focus is given to the electro-responsive ER characteristics of the polymer/clay nanocomposites in terms of the yield stress and viscoelastic properties along with their applications.

  12. The Role of Strigolactones in Nutrient-Stress Responses in Plants

    Directory of Open Access Journals (Sweden)

    Marek Marzec

    2013-04-01

    Full Text Available Strigolactones (SLs are a new group of plant hormones, which have been intensively investigated during the last few years. The wide spectrum of SLs actions, including the regulation of shoot/root architecture, and the stimulation of the interactions between roots and fungi or bacteria, as well as the stimulation of germination of parasitic plants, indicates that this group of hormones may play an important role in the mechanisms that control soil exploration, and the root-mediated uptake of nutrients. Current studies have shown that SLs might be factors that have an influence on the plant response to a deficiency of macronutrients. Experimental data from the last four years have confirmed that the biosynthesis and exudation of SLs are increased under phosphorus and nitrogen deficiency. All these data suggest that SLs may regulate the complex response to nutrient stress, which include not only the modification of the plant developmental process, but also the cooperation with other organisms in order to minimize the effects of threats. In this paper the results of studies that indicate that SLs play an important role in the response to nutrient stress are reviewed and the consequences of the higher biosynthesis and exudation of SLs in response to phosphorus and nitrogen deficiency are discussed.

  13. THE ENERGETIC FUNCTIONS OF PLANT MITOCHONDRIA UNDER STRESS

    Directory of Open Access Journals (Sweden)

    Grabelnych O.I.

    2005-09-01

    Full Text Available This article reviews the involvement of the mitochondrial systems, which maintain the balance of cell energy at different stress conditions. It is shown the functioning of the alternative oxidase, free fatty acids, uncoupling proteins, the rotenone-insensitive NAD(PH dehydrogenases, the ADP/ATP-antiporter, the permeability transition pore and ATP-sensitive potassium channel (К+ATP. It is discussed data about physiological role of these systems in plant cell.

  14. Degradation of aromatic compounds in plants grown under aseptic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Mithaishvili, T.; Ugrekhelidze, D.; Tsereteli, B.; Sadunishvili, T.; Kvesitadze, G. [Durmishidze Inst. of Biochemistry and Biotechnology, Academy of Sciences of Georgia, Tbilisi (Georgia); Scalla, R. [Lab. des Xenobiotiques, INRA, Toulouse (France)

    2005-02-01

    The aim of the work is to investigate the ability of higher plants to absorb and detoxify environmental pollutants - aromatic compounds via aromatic ring cleavage. Transformation of {sup 14}C specifically labelled benzene derivatives, [1-6-{sup 14}C]-nitrobenzene, [1-6-{sup 14}C]-aniline, [1-{sup 14}C]- and [7-{sup 14}C]-benzoic acid, in axenic seedlings of maize (Zea mays L.), kidney bean (Phaseolus vulgaris L.), pea (Pisum sativum L.) and pumpkin (Cucurbita pepo L.) were studied. After penetration in plants, the above xenobiotics are transformed by oxidative or reductive reactions, conjugation with cell endogenous compounds, and binding to biopolymers. The initial stage of oxidative degradation consists in hydroxylation reactions. The aromatic ring can then be cleaved and degraded into organic acids of the Krebs cycle. Ring cleavage is accompanied by {sup 14}CO{sub 2} evolution. Aromatic ring cleavage in plants has thus been demonstrated for different xenobiotics carrying different substitutions on their benzene ring. Conjugation with low molecular peptides is the main pathway of aromatic xenobiotics detoxification. Peptide conjugates are formed both by the initial xenobiotics (except nitrobenzene) and by intermediate transformation products. The chemical nature of the radioactive fragment and the amino acid composition of peptides participating in conjugation were identified. (orig.)

  15. Disease resistance or growth: the role of plant hormones in balancing immune responses and fitness costs

    NARCIS (Netherlands)

    Denance, N.; Sanchez Vallet, A.; Goffner, D.; Molina, A.

    2013-01-01

    Plant growth and response to environmental cues are largely governed by phytohormones. The plant hormones ethylene, jasmonic acid, and salicylic acid (SA) play a central role in the regulation of plant immune responses. In addition, other plant hormones, such as auxins, abscisic acid (ABA),

  16. Increased Sucrose Accumulation Regulates Iron-Deficiency Responses by Promoting Auxin Signaling in Arabidopsis Plants.

    Science.gov (United States)

    Lin, Xian Yong; Ye, Yi Quan; Fan, Shi Kai; Jin, Chong Wei; Zheng, Shao Jian

    2016-02-01

    Previous studies have identified that auxins acts upstream of nitric oxide in regulating iron deficiency responses in roots, but the upstream signaling molecule of auxins remains unknown. In this study, we showed that Fe deficiency increased sucrose (Suc) level in roots of Arabidopsis (Arabidopsis thaliana). Exogenous application of Suc further stimulated Fe deficiency-induced ferric-chelate-reductase (FCR) activity and expression of Fe acquisition-related genes FRO2, IRT1, and FIT in roots. The opposite patterns were observed in the dark treatment. In addition, FCR activity and expression of Fe acquisition-related genes were higher in the Suc high-accumulating transgenic plant 35S::SUC2 but were lower in the Suc low-accumulating mutant suc2-5 compared with wild-type plants under Fe-deficient conditions. Consequently, Fe deficiency tolerance was enhanced in 35S::SUC2 but was compromised in suc2-5. Exogenous Suc also increased root β-glucuronidase (GUS) activity in auxin-inducible reporter DR5-GUS transgenic plants under Fe deficiency. However, exogenous Suc failed to increase FCR activity and expression of Fe acquisition-related genes in the auxin transport-impaired mutants aux1-7 and pin1-1 as well as in the wild-type plants treated with an auxin transport inhibitor under Fe deficiency. In summary, we found that increased Suc accumulation is required for regulating Fe deficiency responses in plants, with auxins acting downstream in transmitting the Fe deficiency signal. © 2016 American Society of Plant Biologists. All Rights Reserved.

  17. NBR1-mediated selective autophagy targets insoluble ubiquitinated protein aggregates in plant stress responses.

    Directory of Open Access Journals (Sweden)

    Jie Zhou

    Full Text Available Plant autophagy plays an important role in delaying senescence, nutrient recycling, and stress responses. Functional analysis of plant autophagy has almost exclusively focused on the proteins required for the core process of autophagosome assembly, but little is known about the proteins involved in other important processes of autophagy, including autophagy cargo recognition and sequestration. In this study, we report functional genetic analysis of Arabidopsis NBR1, a homolog of mammalian autophagy cargo adaptors P62 and NBR1. We isolated two nbr1 knockout mutants and discovered that they displayed some but not all of the phenotypes of autophagy-deficient atg5 and atg7 mutants. Like ATG5 and ATG7, NBR1 is important for plant tolerance to heat, oxidative, salt, and drought stresses. The role of NBR1 in plant tolerance to these abiotic stresses is dependent on its interaction with ATG8. Unlike ATG5 and ATG7, however, NBR1 is dispensable in age- and darkness-induced senescence and in resistance to a necrotrophic pathogen. A selective role of NBR1 in plant responses to specific abiotic stresses suggest that plant autophagy in diverse biological processes operates through multiple cargo recognition and delivery systems. The compromised heat tolerance of atg5, atg7, and nbr1 mutants was associated with increased accumulation of insoluble, detergent-resistant proteins that were highly ubiquitinated under heat stress. NBR1, which contains an ubiquitin-binding domain, also accumulated to high levels with an increasing enrichment in the insoluble protein fraction in the autophagy-deficient mutants under heat stress. These results suggest that NBR1-mediated autophagy targets ubiquitinated protein aggregates most likely derived from denatured or otherwise damaged nonnative proteins generated under stress conditions.

  18. Optimized production planning model for a multi-plant cultivation system under uncertainty

    Science.gov (United States)

    Ke, Shunkui; Guo, Doudou; Niu, Qingliang; Huang, Danfeng

    2015-02-01

    An inexact multi-constraint programming model under uncertainty was developed by incorporating a production plan algorithm into the crop production optimization framework under the multi-plant collaborative cultivation system. In the production plan, orders from the customers are assigned to a suitable plant under the constraints of plant capabilities and uncertainty parameters to maximize profit and achieve customer satisfaction. The developed model and solution method were applied to a case study of a multi-plant collaborative cultivation system to verify its applicability. As determined in the case analysis involving different orders from customers, the period of plant production planning and the interval between orders can significantly affect system benefits. Through the analysis of uncertain parameters, reliable and practical decisions can be generated using the suggested model of a multi-plant collaborative cultivation system.

  19. Crossfit analysis: a novel method to characterize the dynamics of induced plant responses

    NARCIS (Netherlands)

    Jansen, J.J.; Van Dam, N.M.; Hoefsloot, H.C.J.; Smilde, A.K.

    2009-01-01

    Background Many plant species show induced responses that protect them against exogenous attacks. These responses involve the production of many different bioactive compounds. Plant species belonging to the Brassicaceae family produce defensive glucosinolates, which may greatly influence their

  20. Crossfit analysis: a novel method to characterize the dynamics of induced plant responses

    NARCIS (Netherlands)

    Jansen, J.J.; van Dam, N.M.; Hoefsloot, H.C.J.; Smilde, A.K.

    2009-01-01

    Background: Many plant species show induced responses that protect them against exogenous attacks. These responses involve the production of many different bioactive compounds. Plant species belonging to the Brassicaceae family produce defensive glucosinolates, which may greatly influence their

  1. Assessment of (Fouquieria splendens ssp. breviflora Cell Cultures Response Under to Water Stress

    Directory of Open Access Journals (Sweden)

    Leonor Angélica Guerrero Zúñiga

    2017-05-01

    Full Text Available Plant cell cultures are homogenous experimental systems, highly controllable that allow the study of short and large water stress adaptations without the interference of the different tissues and development of plants. An approach to understand these adaptations is through the presence of induced proteins; as a result of changes in genetic expression. This work analyze the response of Fouquieria splendens ssp. breviflora cell cultures exposed to abscisic acid (ABA, through the electrophoretic characterization of quantity and quality of stress induced proteins. There were recorded low molecular weight polypeptides (< 35kDa, common in experiments under ABA 10mM, followed by the association with 20 and 30mM ABA conditions, with a particularly response of cell cultures without the stress agent.

  2. On seismic response characteristics of floating nuclear plant barge, (1)

    International Nuclear Information System (INIS)

    Hagiwara, Yutaka; Masuko, Yoshio; Nakamura, Shuuji; Matsuura, Shinichi; Shiojiri, Hiroo

    1986-01-01

    Since Floating Nuclear Plants (FNP) are considered to be isolated from horizontal seismic motion, reduction and standardization of the aseismic design conditions of the floating plants are anticipated. However, studies on FNP in closed and shallow basin have almost not been executed to data, and there are many problems remaining unsolved. The purpose of the present report is to obtain sufficient elementary data and materials on the seismic response of floating body in the closed and shallow basin. Some interesting points to be extracted from shaking table tests, finite element analyses and simplified analyses are summarized as follows: 1) The seismic isolation characteristics of the floating body are remarkable to short period horizontal seismic motion. 2) Resonances of the floating body's motion, which coupled with surface waves, are induced by long period horizontal seismic motion. 3) Vertical seismic motion is transmitted directly to the floating body. (author)

  3. Transcriptional Responses in the Hemiparasitic Plant Triphysaria versicolor to Host Plant Signals1[w

    Science.gov (United States)

    Matvienko, Marta; Torres, Manuel J.; Yoder, John I.

    2001-01-01

    Parasitic plants in the Scrophulariaceae use chemicals released by host plant roots to signal developmental processes critical for heterotrophy. Haustoria, parasitic plant structures that attach to and invade host roots, develop on roots of the hemiparasitic plant Triphysaria versicolor within a few hours of exposure to either maize (Zea mays) root exudate or purified haustoria-inducing factors. We prepared a normalized, subtractive cDNA library enriched for transcripts differentially abundant in T. versicolor root tips treated with the allelopathic quinone 2,6-dimethoxybenzoquinone (DMBQ). Northern analyses estimated that about 10% of the cDNAs represent transcripts strongly up-regulated in roots exposed to DMBQ. Northern and reverse northern analyses demonstrated that most DMBQ-responsive messages were similarly up-regulated in T. versicolor roots exposed to maize root exudates. From the cDNA sequences we assembled a unigene set of 137 distinct transcripts and assigned functions by homology comparisons. Many of the proteins encoded by the transcripts are predicted to function in quinone detoxification, whereas others are more likely associated with haustorium development. The identification of genes transcriptionally regulated by haustorium-inducing factors provides a framework for dissecting genetic pathways recruited by parasitic plants during the transition to heterotrophic growth. PMID:11553755

  4. Plant defence responses in oilseed rape MINELESS plants after attack by the cabbage moth Mamestra brassicae.

    Science.gov (United States)

    Ahuja, Ishita; van Dam, Nicole Marie; Winge, Per; Trælnes, Marianne; Heydarova, Aysel; Rohloff, Jens; Langaas, Mette; Bones, Atle Magnar

    2015-02-01

    The Brassicaceae family is characterized by a unique defence mechanism known as the 'glucosinolate-myrosinase' system. When insect herbivores attack plant tissues, glucosinolates are hydrolysed by the enzyme myrosinase (EC 3.2.1.147) into a variety of degradation products, which can deter further herbivory. This process has been described as 'the mustard oil bomb'. Additionally, insect damage induces the production of glucosinolates, myrosinase, and other defences. Brassica napus seeds have been genetically modified to remove myrosinase-containing myrosin cells. These plants are termed MINELESS because they lack myrosin cells, the so-called toxic mustard oil mines. Here, we examined the interaction between B. napus wild-type and MINELESS plants and the larvae of the cabbage moth Mamestra brassicae. No-choice feeding experiments showed that M. brassicae larvae gained less weight and showed stunted growth when feeding on MINELESS plants compared to feeding on wild-type plants. M. brassicae feeding didn't affect myrosinase activity in MINELESS plants, but did reduce it in wild-type seedlings. M. brassicae feeding increased the levels of indol-3-yl-methyl, 1-methoxy-indol-3-yl-methyl, and total glucosinolates in both wild-type and MINELESS seedlings. M. brassicae feeding affected the levels of glucosinolate hydrolysis products in both wild-type and MINELESS plants. Transcriptional analysis showed that 494 and 159 genes were differentially regulated after M. brassicae feeding on wild-type and MINELESS seedlings, respectively. Taken together, the outcomes are very interesting in terms of analysing the role of myrosin cells and the glucosinolate-myrosinase defence system in response to a generalist cabbage moth, suggesting that similar studies with other generalist or specialist insect herbivores, including above- and below-ground herbivores, would be useful. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  5. Response of tomato to radiation intensity and air temperature under plastic-house ultraviolet protection

    International Nuclear Information System (INIS)

    Syakur, A.

    2002-01-01

    Enhance of ultraviolet radiation intensity on the earth surface affected by ozon depletion on stratospheric layer cause changing on the response of plant to radiation quality. One technique for reducing photo destructive UV radiation is micro climate modification by using mulch and plastic-cover UV protection. So that, growth and yield of plant can be optimalized. This research designed an experiment to find out the effect of two kinds of plastic-cover, UV plastic and conventional plastic, on microclimate condition and tomato performance under plastic-house. The result of this research described that mulch and plastic cover can modify radiation and air temperature under plastics-house, but it can not improve growth and yield of the tomato [in

  6. Utilization of 15NO3− by nodulated soybean plants under conditions of root hypoxia

    OpenAIRE

    Nunes Menolli Lanza, Luciana; Ferreira Lanza, Daniel Carlos; Sodek, Ladaslav

    2014-01-01

    Waterlogging of soils is common in nature. The low availability of oxygen under these conditions leads to hypoxia of the root system impairing the development and productivity of the plant. The presence of nitrate under flooding conditions is regarded as being beneficial towards tolerance to this stress. However, it is not known how nodulated soybean plants, cultivated in the absence of nitrate and therefore not metabolically adapted to this compound, would respond to nitrate under root hypox...

  7. Shared and unique responses of plants to multiple individual stresses and stress combinations: physiological and molecular mechanisms

    Science.gov (United States)

    Pandey, Prachi; Ramegowda, Venkategowda; Senthil-Kumar, Muthappa

    2015-01-01

    In field conditions, plants are often simultaneously exposed to multiple biotic and abiotic stresses resulting in substantial yield loss. Plants have evolved various physiological and molecular adaptations to protect themselves under stress combinations. Emerging evidences suggest that plant responses to a combination of stresses are unique from individual stress responses. In addition, plants exhibit shared responses which are common to individual stresses and stress combination. In this review, we provide an update on the current understanding of both unique and shared responses. Specific focus of this review is on heat–drought stress as a major abiotic stress combination and, drought–pathogen and heat–pathogen as examples of abiotic–biotic stress combinations. We also comprehend the current understanding of molecular mechanisms of cross talk in relation to shared and unique molecular responses for plant survival under stress combinations. Thus, the knowledge of shared responses of plants from individual stress studies and stress combinations can be utilized to develop varieties with broad spectrum stress tolerance. PMID:26442037

  8. Plant protection under conditions of radioactive contamination of agricultural lands

    International Nuclear Information System (INIS)

    Filipas, A.S.; Oulianenko, L.N.; Pimenov, E.P.

    1995-01-01

    Increasing influence of anthropogenic contaminants as well as substantiated risk of the action of ionizing radiation on agroecosystems suggest the necessity of studying both the state of separate components of cenosis and search for methods on retention of ecosystem stability as a whole. In this case it should be taken into account that by retention of resistance of living organisms to the action of stress agents not only genetically conditioned potential but induction of protective reactions at the expense of ecogene action is of deciding significance as well. Protection of agricultural plants on the territories subjected to radioactive contamination resulting from the ChNPP accident brings attention of research works to a series of problems, the main one being the minimization of pesticide use by the total ecologization of technological processes, in plant growing. But an ordinary discontinuance of conducting protective chemical measures leads to growth in the number of harmful organisms in crop sowings and as a consequence an increase of crop loss and decrease of its quality. It is possible to solve this problem by introduction of measures increasing the resistance of agricultural plants to the action of unfavorable factors of environment. Application of biologically active substances (BAS) of natural and synthetic nature for incrustation of seeds fits into these methods. For the territories with increased content of radionuclides and especially by their rehabilitation the methods of preventive treatments directed to retarding the development of harmful organisms in crop sowings and excluding subsequent technological operations on chemical protection of sowings takes on special significance as it is directly connected with the problem of radiation burden on workers of agroindustrial complex

  9. High-Arctic Plant-Herbivore Interactions under Climate Influence

    DEFF Research Database (Denmark)

    Berg, Thomas B.; Schmidt, Niels M.; Høye, Toke Thomas

    This chapter focuses on a 10-year data series from Zackenberg on the trophic interactions between two characteristic arctic plant species, arctic willow Salix arctica and mountain avens Dryas octopetala, and three herbivore species covering the very scale of size present at Zackenberg, namely...... production upon which the herbivores depend, and snow may be the most important climatic factor affecting the different trophic levels and the interactions between them. Hence, the spatio-temporal distribution of snow, as well as thawing events during winter, may have considerable effects on the herbivores...

  10. Inspection of nuclear power plants under construction in Spain

    International Nuclear Information System (INIS)

    Santoma, L.

    1977-01-01

    Brief summary of the situation of the nuclear industry in Spain, in order to better understand the questions involved in the inspection of the Spanish nuclear power plants, as well as the experience acquired, followed by a description of some of the problems which have arisen during the construction phase. Also the problems faced by the Inspection of the Junta de Energia Nuclear are described in order to fulfill the missions entrusted to it. Finally, some recommendations are made in light of the experience had by Spain.(author) [es

  11. Leak before break application in French PWR plants under operation

    Energy Technology Data Exchange (ETDEWEB)

    Faidy, C. [EDF SEPTEN, Villeurbanne (France)

    1997-04-01

    Practical applications of the leak-before break concept are presently limited in French Pressurized Water Reactors (PWR) compared to Fast Breeder Reactors. Neithertheless, different fracture mechanic demonstrations have been done on different primary, auxiliary and secondary PWR piping systems based on similar requirements that the American NUREG 1061 specifications. The consequences of the success in different demonstrations are still in discussion to be included in the global safety assessment of the plants, such as the consequences on in-service inspections, leak detection systems, support optimization,.... A large research and development program, realized in different co-operative agreements, completes the general approach.

  12. Biotic interactions overrule plant responses to climate, depending on the species' biogeography.

    Science.gov (United States)

    Welk, Astrid; Welk, Erik; Bruelheide, Helge

    2014-01-01

    This study presents an experimental approach to assess the relative importance of climatic and biotic factors as determinants of species' geographical distributions. We asked to what extent responses of grassland plant species to biotic interactions vary with climate, and to what degree this variation depends on the species' biogeography. Using a gradient from oceanic to continental climate represented by nine common garden transplant sites in Germany, we experimentally tested whether congeneric grassland species of different geographic distribution (oceanic vs. continental plant range type) responded differently to combinations of climate, competition and mollusc herbivory. We found the relative importance of biotic interactions and climate to vary between the different components of plant performance. While survival and plant height increased with precipitation, temperature had no effect on plant performance. Additionally, species with continental plant range type increased their growth in more benign climatic conditions, while those with oceanic range type were largely unable to take a similar advantage of better climatic conditions. Competition generally caused strong reductions of aboveground biomass and growth. In contrast, herbivory had minor effects on survival and growth. Against expectation, these negative effects of competition and herbivory were not mitigated under more stressful continental climate conditions. In conclusion we suggest variation in relative importance of climate and biotic interactions on broader scales, mediated via species-specific sensitivities and factor-specific response patterns. Our results have important implications for species distribution models, as they emphasize the large-scale impact of biotic interactions on plant distribution patterns and the necessity to take plant range types into account.

  13. Warming Experiments Underpredict Plant Phenological Responses to Climate Change

    Science.gov (United States)

    Wolkovich, E. M.; Cook, B. I.; Allen, J. M.; Crimmins, T. M.; Betancourt, J. L.; Travers, S. E.; Pau, S.; Regetz, J.; Davies, T. J.; Kraft, N. J. B.; hide

    2012-01-01

    Warming experiments are increasingly relied on to estimate plant responses to global climate change. For experiments to provide meaningful predictions of future responses, they should reflect the empirical record of responses to temperature variability and recent warming, including advances in the timing of flowering and leafing. We compared phenology (the timing of recurring life history events) in observational studies and warming experiments spanning four continents and 1,634 plant species using a common measure of temperature sensitivity (change in days per degree Celsius). We show that warming experiments underpredict advances in the timing of flowering and leafing by 8.5-fold and 4.0-fold, respectively, compared with long-term observations. For species that were common to both study types, the experimental results did not match the observational data in sign or magnitude. The observational data also showed that species that flower earliest in the spring have the highest temperature sensitivities, but this trend was not reflected in the experimental data. These significant mismatches seem to be unrelated to the study length or to the degree of manipulated warming in experiments. The discrepancy between experiments and observations, however, could arise from complex interactions among multiple drivers in the observational data, or it could arise from remediable artefacts in the experiments that result in lower irradiance and drier soils, thus dampening the phenological responses to manipulated warming. Our results introduce uncertainty into ecosystem models that are informed solely by experiments and suggest that responses to climate change that are predicted using such models should be re-evaluated.

  14. Ultraviolet-B radiation effects on plants: induction of morphogenic responses

    International Nuclear Information System (INIS)

    Jansen, M.A.K.

    2002-01-01

    Plants raised under field conditions are acclimated to ambient levels of solar UV-B radiation. Morphogenic responses are part of the UV-B acclimation process and have been hypothesized to contribute to UV avoidance. UV-B induced morphogenic responses include inhibition of hypocotyl and stem elongation, leaf curling, leaf thickening and increased axillary branching. So far, neither the photosensory nor the signal transduction mechanism involved in UV-B mediated morphogenesis has been identified. The combination of classical photobiological techniques and Arabidopsis genetic resources comprises a powerful tool for the analysis of morphogenic responses. However, no morphogenic mutants, specifically altered in their response to UV-B, have yet been identified. In this paper we discuss the possibility that some UV-B driven morphogenic responses do not involve a dedicated photosensory system, but rather are a consequence of UV-B induced changes in secondary metabolism. UV-B induced flavonoid aglycones and phenol-oxidizing peroxidases can affect, respectively, polar auxin transport and auxin catabolism, and hence plant architecture. Integration of genetic, photobiological, biochemical and physiological approaches is necessary to fully appraise the ecophysiological role of UV-B radiation in controlling plant architecture. (author)

  15. Responses to Environmental Stress in Plants Adapted to Mediterranean Gypsum Habitats

    Directory of Open Access Journals (Sweden)

    Josep V. LLINARES

    2015-03-01

    Full Text Available Gypsum areas are stressful environments inhabited by gypsophytes, plants that are exclusive for such habitats, and by plants that grow on gypsum but also on other soil types, the so-called gypsovags. To investigate possible differences between gypsovags and gypsophytes with respect to basic stress response mechanisms, two common osmolytes, glycine betaine and total soluble sugars, as well as monovalent (Na+ and K+ and bivalent (Ca2+ and Mg2+ cations, were quantified, under field conditions, in two Iberian endemic gypsophytes (Gypsophila struthium subsp. hispanica and Ononis tridentata and two common Mediterranean gypsovags (Rosmarinus officinalis and Helianthemum syriacum. Their spatial variation according to a topographic gradient and their temporal variation over a period of three successive seasons were correlated with climatic data and soil characteristics. This analysis confirmed that water stress is the main environmental stress factor in gypsum habitats, whereas the percentage of gypsum in the soil does not seem to play any relevant role in the activation of stress responses in plants. Glycine betaine may contribute to stress tolerance in the gypsophytes, but not in the gypsovags, according to the close correlation found between the level of this osmolyte and the gypsophily of the investigated taxa. Cation contents in the plants did not correlate with those present in the soil, but the gypsophytes have higher levels of Ca2+ and Mg2+ than the gypsovags, under all environmental conditions, which may represent an adaptation mechanism to their specific habitat.

  16. Uniconazole effect on endogenous hormones, proteins and proline contents of barley plants (Hordium vulgare under salinity stress (NaCl

    Directory of Open Access Journals (Sweden)

    MOHAMED A. BAKHETA

    2014-05-01

    Full Text Available Bakheta MA, Hussein MM. 2014. Uniconazole effect on endogenous hormones, proteins and proline contents of barley plants (Hordium vulgare under salinity stress (NaCl. Nusantara Bioscience 6: 39-44. Pot experiments were carried out during two growth seasons 2010 / 2011 under greenhouse conditions of the National Research Centre, Dokki, Cairo, Egypt to investigate the response of barley plants (Hordium vulgare L grown under salinity stress (2500 or 5000 ppm to spraying with solutions of uniconazole at 150 or 200 ppm. The obtained results showed that irrigation with saline solutions caused increases in the amounts of abscisic acid (ABA, crude protein, total soluble-protein and proline contents. The results showed that spraying barley plants grown under saline solutions with uniconazole increased endogenous hormone contents of ABA, cytokinins, crude protein, total soluble protein and proline but caused decreases in the amounts of endogenous indole acetic acid (IAA and gibberellic acid (GA3. High protection of abscisic acid in treating plants with uniconazole and under salt stress (interaction effect increases proline, proteins and soluble protein which has been proposed to act as compatible solutes that adjust the osmotic potential in the cytoplasm. Thus, these biochemical characters can be used as a metabolic marker in relation to salinity stress.

  17. Invasive alien plant species dynamics in the Himalayan region under climate change.

    Science.gov (United States)

    Lamsal, Pramod; Kumar, Lalit; Aryal, Achyut; Atreya, Kishor

    2018-01-25

    Climate change will impact the dynamics of invasive alien plant species (IAPS). However, the ability of IAPS under changing climate to invade mountain ecosystems, particularly the Himalayan region, is less known. This study investigates the current and future habitat of five IAPS of the Himalayan region using MaxEnt and two representative concentration pathways (RCPs). Two invasive species, Ageratum conyzoides and Parthenium hysterophorus, will lose overall suitable area by 2070, while Ageratina adenophora, Chromolaena odorata and Lantana camara will gain suitable areas and all of them will retain most of the current habitat as stable. The southern Himalayan foothills will mostly conserve species ecological niches, while suitability of all the five species will decrease with increasing elevation. Such invasion dynamics in the Himalayan region could have impacts on numerous ecosystems and their biota, ecosystem services and human well-being. Trans-boundary response strategies suitable to the local context of the region could buffer some of the likely invasion impacts.

  18. Peculiarities of 137Cs translocation in higher plants under environmental and laboratory conditions

    International Nuclear Information System (INIS)

    Marciulioniene, D.; Kiponas, D.; Luksiene, B.

    2008-01-01

    Accumulation of technogenic 137 Cs in higher plant roots and above-ground part and comparison of 137 Cs and 40 K transfer from roots to the above-ground part of plant as well as distribution within above-ground part of plant under environmental conditions were investigated. Parallely, the results of the investigations of 137 Cs accumulation in the roots and shoots of test-organism Lepidium sativum L. in the model hydroponic system aqueous solution-solid phase-plant were analyzed. Peculiarities of transfer of this radionuclide from roots to shoots during the entire plant growing period under experimental conditions were determined. 137 Cs activity in the tested plants of meadow ecotop was on an average 6-fold lower than in the plants of swamp and 10-fold lower than in the plants of forest ecotop. Differences in 137 Cs and 40 K transfer from roots to the above-ground part of plant and their distribution in plants indicate particular biological metabolism of these radionuclides in plants. Increased levels of 137 Cs in soil practically did not affect the 40 K transfer from roots to the above-ground part of plants. The results of investigations under natural and laboratory conditions show that increasing contamination of growth medium with 137 Cs caused higher accumulation of this radionuclide in roots but its transfer from roots to the above-ground part of plant decreased or changed insignificantly. 137 Cs transfer from roots to above-ground part under natural (Artemisia vulgaris) and laboratory (Lepidium sativum) conditions was rather similar. (authors)

  19. Leaf miner incidence in coffee plants under different drip irrigation regimes and planting densities

    Directory of Open Access Journals (Sweden)

    Gleice Aparecida Assis

    2012-02-01

    Full Text Available The objective of this work was to evaluate the effect of different drip irrigation regimes and planting densities on the incidence of the leaf miner, Leucoptera coffeella, in arabica coffee plants for one year. The experiment was carried out in 2008, in a complete randomized block design, in a split-plot in time arrangement, with four replicates. The treatments consisted of four drip irrigation regimes - soil water balance, irrigations at 20 and 60 kPa soil tensions, and a nonirrigated treatment -, which were distributed at three plant densities: 2, 500, 5, 000, and 10, 000 plants per hectare. The evaluations were made on a monthly basis between January and December 2008. The highest pest occurrence period was from August to November, a season with low-air relative humidity preceded by a drought period. Irrigated coffee plants showed an incidence of intact mines 2.2 times lower than that of nonirrigated plants. Irrigation and increasing of plant density contribute to the reduction of coffee leaf miner occurrence.

  20. Uncertainty in predicting range dynamics of endemic alpine plants under climate warming.

    Science.gov (United States)

    Hülber, Karl; Wessely, Johannes; Gattringer, Andreas; Moser, Dietmar; Kuttner, Michael; Essl, Franz; Leitner, Michael; Winkler, Manuela; Ertl, Siegrun; Willner, Wolfgang; Kleinbauer, Ingrid; Sauberer, Norbert; Mang, Thomas; Zimmermann, Niklaus E; Dullinger, Stefan

    2016-07-01

    Correlative species distribution models have long been the predominant approach to predict species' range responses to climate change. Recently, the use of dynamic models is increasingly advocated for because these models better represent the main processes involved in range shifts and also simulate transient dynamics. A well-known problem with the application of these models is the lack of data for estimating necessary parameters of demographic and dispersal processes. However, what has been hardly considered so far is the fact that simulating transient dynamics potentially implies additional uncertainty arising from our ignorance of short-term climate variability in future climatic trends. Here, we use endemic mountain plants of Austria as a case study to assess how the integration of decadal variability in future climate affects outcomes of dynamic range models as compared to projected long-term trends and uncertainty in demographic and dispersal parameters. We do so by contrasting simulations of a so-called hybrid model run under fluctuating climatic conditions with those based on a linear interpolation of climatic conditions between current values and those predicted for the end of the 21st century. We find that accounting for short-term climate variability modifies model results nearly as differences in projected long-term trends and much more than uncertainty in demographic/dispersal parameters. In particular, range loss and extinction rates are much higher when simulations are run under fluctuating conditions. These results highlight the importance of considering the appropriate temporal resolution when parameterizing and applying range-dynamic models, and hybrid models in particular. In case of our endemic mountain plants, we hypothesize that smoothed linear time series deliver more reliable results because these long-lived species are primarily responsive to long-term climate averages. © 2016 John Wiley & Sons Ltd.

  1. Transcriptional Regulation of Aluminum-Tolerance Genes in Higher Plants: Clarifying the Underlying Molecular Mechanisms

    Directory of Open Access Journals (Sweden)

    Abhijit A. Daspute

    2017-08-01

    Full Text Available Aluminum (Al rhizotoxicity is one of the major environmental stresses that decrease global food production. Clarifying the molecular mechanisms underlying Al tolerance may contribute to the breeding of Al-tolerant crops. Recent studies identified various Al-tolerance genes. The expression of these genes is inducible by Al. Studies of the major Arabidopsis thaliana Al-tolerance gene, ARABIDOPSIS THALIANA ALUMINUM-ACTIVATED MALATE TRANSPORTER 1 (AtALMT1, which encodes an Al-activated malate transporter, revealed that the Al-inducible expression is regulated by a SENSITIVE TO PROTON RHIXOTOXICITY 1 (STOP1 zinc-finger transcription factor. This system, which involves STOP1 and organic acid transporters, is conserved in diverse plant species. The expression of AtALMT1 is also upregulated by several phytohormones and hydrogen peroxide, suggesting there is crosstalk among the signals involved in the transcriptional regulation of AtALMT1. Additionally, phytohormones and reactive oxygen species (ROS activate various transcriptional responses, including the expression of genes related to increased Al tolerance or the suppression of root growth under Al stress conditions. For example, Al suppressed root growth due to abnormal accumulation of auxin and cytokinin. It activates transcription of TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS 1 and other phytohormone responsive genes in distal transition zone, which causes suppression of root elongation. On the other hand, overexpression of Al inducible genes for ROS-detoxifying enzymes such as GLUTATHIONE–S-TRANSFERASE, PEROXIDASE, SUPEROXIDE DISMUTASE enhances Al resistance in several plant species. We herein summarize the complex transcriptional regulation of an Al-inducible genes affected by STOP1, phytohormones, and ROS.

  2. Plant transducers of the endoplasmic reticulum unfolded protein response

    KAUST Repository

    Iwata, Yuji

    2012-12-01

    The unfolded protein response (UPR) activates a set of genes to overcome accumulation of unfolded proteins in the endoplasmic reticulum (ER), a condition termed ER stress, and constitutes an essential part of ER protein quality control that ensures efficient maturation of secretory and membrane proteins in eukaryotes. Recent studies on Arabidopsis and rice identified the signaling pathway in which the ER membrane-localized ribonuclease IRE1 (inositol-requiring enzyme 1) catalyzes unconventional cytoplasmic splicing of mRNA, thereby producing the active transcription factor Arabidopsis bZIP60 (basic leucine zipper 60) and its ortholog in rice. Here we review recent findings identifying the molecular components of the plant UPR, including IRE1/bZIP60 and the membrane-bound transcription factors bZIP17 and bZIP28, and implicating its importance in several physiological phenomena such as pathogen response. © 2012 Elsevier Ltd.

  3. Physiological responses and differential gene expression in Prunus rootstocks under iron deficiency conditions.

    Science.gov (United States)

    Gonzalo, María José; Moreno, María Ángeles; Gogorcena, Yolanda

    2011-06-15

    Two Prunus rootstocks, the Myrobalan plum P 2175 and the interspecific peach-almond hybrid, Felinem, were studied to characterize their biochemical and molecular responses induced under iron-Deficient conditions. Plants of both genotypes were submitted to different treatments using a hydroponic system that permitted removal of Fe from the nutrient solution. Control plants were grown in 90 μM Fe (III)-EDTA, Deficient plants were grown in an iron free solution, and plants submitted to an Inductor treatment were resupplied with 180 μM Fe (III)-EDTA over 1 and 2 days after a period of 4 or 15 days of growth on an iron-free solution. Felinem increased the activity of the iron chelate reductase (FC-R) in the Inductor treatment after 4 days of iron deprivation. In contrast, P 2175 did not show any response after at least 15 days without iron. The induction of the FC-R activity in this genotype was coincident in time with the medium acidification. These results suggest two different mechanisms of iron chlorosis tolerance in both Strategy I genotypes. Felinem would use the iron reduction as the main mechanism to capture the iron from the soil, and in P 2175, the mechanism of response would be slower and start with the acidification of the medium synchronized with the gradual loss of chlorophyll in leaves. To better understand the control of these responses at the molecular level, the differential expression of PFRO2, PIRT1 and PAHA2 genes involved in the reductase activity, the iron transport in roots, and the proton release, respectively, were analyzed. The expression of these genes, estimated by quantitative real-time PCR, was different between genotypes and among treatments. The results were in agreement with the physiological responses observed. Copyright © 2011 Elsevier GmbH. All rights reserved.

  4. Prioritizing conservation areas for coastal plant diversity under increasing urbanization.

    Science.gov (United States)

    Doxa, Aggeliki; Albert, Cécile Hélène; Leriche, Agathe; Saatkamp, Arne

    2017-10-01

    Coastal urban expansion will continue to drive further biodiversity losses, if conservation targets for coastal ecosystems are not defined and met. Prioritizing areas for future protected area networks is thus an urgent task in such urbanization-threatened ecosystems. Our aim is to quantify past and future losses of coastal vegetation priority areas due to urbanization and assess the effectiveness of the existing protected area network for conservation. We conduct a prioritization analysis, based on 82 coastal plants, including common and IUCN red list species, in a highly-urbanized but biotically diverse region, in South-Eastern France. We evaluate the role of protected areas, by taking into account both strict and multi-use areas. We assess the impact of past and future urbanization on high priority areas, by combining prioritization analyses and urbanization models. We show that half of the highly diverse areas have already been lost due to urbanization. Remaining top priority areas are also among the most exposed to future urban expansion. The effectiveness of the existing protected area (PA) network is only partial. While strict PAs coincide well with top priority areas, they only represent less than one third of priority areas. The effectiveness of multi-use PAs, such as the Natura 2000 network, also remains limited. Our approach highlights the impact of urbanization on plant conservation targets. By modelling urbanization, we manage to identify those areas where protection could be more efficient to limit further losses. We suggest to use our approach in the future to expand the PA network in order to achieve the 2020 Aichi biodiversity targets. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Plant 9-lox oxylipin metabolism in response to arbuscular mycorrhiza.

    Science.gov (United States)

    León Morcillo, Rafael Jorge; Ocampo, Juan A; García Garrido, José M

    2012-12-01

    The establishment of an Arbuscular Mycorrhizal symbiotic interaction (MA) is a successful strategy to substantially promote plant growth, development and fitness. Numerous studies have supported the hypothesis that plant hormones play an important role in the recognition and establishment of symbiosis. Particular attention has been devoted to jasmonic acid (JA) and its derivates, the jasmonates, which are believed to play a major role in AM symbiosis. Jasmonates belong to a diverse class of lipid metabolites known as oxylipins that include other biologically active molecules. Recent transcriptional analyses revealed upregulation of the oxylipin pathway during AM symbiosis in mycorrhizal tomato roots and point a key regulatory feature for oxylipins during AM symbiosis in tomato, particularly these derived from the action of 9-lipoxygenases (9-LOX). In this mini-review we highlight recent progress understanding the function of oxylipins in the establishment of the AM symbiosis and hypothesize that the activation of the 9-LOX pathway might be part of the activation of host defense responses which will then contribute to both, the control of AM fungal spread and the increased resistance to fungal pathogens in mycorrhizal plants.

  6. Boron deficiency in woody plants: various responses and tolerance mechanisms

    Directory of Open Access Journals (Sweden)

    Nannan eWang

    2015-10-01

    Full Text Available Boron (B is an essential microelement for higher plants, and its deficiency is widespread around the world and constrains the productivity of both agriculture and forestry. In the last decades, accumulating studies on model or herbaceous plants have contributed greatly to our understanding of the complex network of B-deficiency responses and mechanisms for tolerance. In woody plants, however, only a few studies have been conducted and they are not well synthesised. Trees have a larger body size, longer lifespan and more B reserves than do herbaceous plants, indicating that woody species might undergo long-term or mild B deficiency more commonly and that a more complicated B reserves must accordingly be developed to cope with B deficiency. In addition, the highly heterozygous genetic background of tree species suggests that they may have a more complicated mechanism of response and tolerance to B deficiency than do model plants.B-deficient trees usually exhibit two key visible symptoms: depression of growing points (root tip, bud, flower, and young leaf and deformity of organs (root, shoot, leaf, and fruit. These symptoms may be ascribed to B functioning in the cell wall and membrane, and B deficiency results in damage to vascular tissues and the suppression of both B and water transport. B deficiency also affects metabolic processes, such as increased lignin and phenol, and decreased leaf photosynthesis. These negative effects will influence the quality and quantity of wood, fruit and other agricultural products.B efficiency probably originates from a combined effect of three processes: B uptake, B translocation and retranslocation, and B utilization. Root morphology and mycorrhiza can affect the B uptake efficiency of trees. During B translocation from the root to shoot, differences in B concentration between root cell saps and xylem exudates, as well as water use efficiency, may play key roles in tolerance to B deficiency. In addition, B

  7. Plants' use of different nitrogen forms in response to crude oil contamination

    International Nuclear Information System (INIS)

    Nie Ming; Lu Meng; Yang Qiang; Zhang Xiaodong; Xiao Ming; Jiang Lifen; Yang Ji; Fang Changming; Chen Jiakuan; Li Bo

    2011-01-01

    In this study, we investigated Phragmites australis' use of different forms of nitrogen (N) and associated soil N transformations in response to petroleum contamination. 15 N tracer studies indicated that the total amount of inorganic and organic N assimilated by P. australis was low in petroleum-contaminated soil, while the rates of inorganic and organic N uptake on a per-unit-biomass basis were higher in petroleum-contaminated soil than those in un-contaminated soil. The percentage of organic N in total plant-assimilated N increased with petroleum concentration. In addition, high gross N immobilization and nitrification rates relative to gross N mineralization rate might reduce inorganic-N availability to the plants. Therefore, the enhanced rate of N uptake and increased importance of organic N in plant N assimilation might be of great significance to plants growing in petroleum-contaminated soils. Our results suggest that plants might regulate N capture under petroleum contamination. - Plant strategies of utilizing nitrogen in crude oil-contaminated soils.

  8. Effect of Bio char on Plant Growth and Aluminium Form of Soil under Aluminium Stress

    Science.gov (United States)

    Qian, Lianwen; Li, Qingbiao; Sun, Jingwei; Feng, Ying

    2018-01-01

    Aluminium-enriched acid red soils in South China easily cause aluminium toxicity to plants, but biochip can improve soils and eliminate soil contaminations. In this project, biochip was used in potted plant control test to study the effect of biochip on plant growth in soil under acid aluminium stress and the migration and conversion of aluminium in plant-soil system. The fin dings show that the application of biochip increases the pH value of soil under aluminium stress significantly, changes the existing form of aluminium ion in soil, reduces the plants’ absorption of aluminium, and alleviates the aluminium toxicity to plants, but too much biochip may inhibit the growth of plants. In this case, further study should be carried out as regards the volume and way of biochip input in practical applications as well as the timeliness of aluminium toxicity removal.

  9. Physiological Responses and Yield of Wheat Plants in Zinc-Mediated Alleviation of Drought Stress

    Directory of Open Access Journals (Sweden)

    Dongyun Ma

    2017-05-01

    Full Text Available To evaluate the physiological responses of wheat to zinc (Zn fertilizer application under drought stress, pot, and field experiments were conducted on wheat plants grown under different soil moistures and treated with soil and foliar Zn applications. Photosynthetic characteristics, antioxidant content, Zn element concentration, and the transcription level of genes involved in antioxidant biosynthesis were analyzed. Zn application increased SPAD and Fv/Fm of wheat flag leaves, while decreased lipid peroxidation levels and H2O2 content. Zn application increased the antioxidant content (ascorbate, reduced glutathione, total phenolic, and total flavonoid of wheat flag leaves, and enhanced the relative expression levels of two antioxidant enzyme genes, four ascorbate–glutathione cycle genes, and two flavonoid biosynthesis pathway genes under drought stress. Soil Zn application increased grain yield and Zn concentration by 10.5 and 15.8%, 22.6 and 9.7%, and 28.2 and 32.8% under adequate water supply, moderate drought, and severe drought, respectively. Furthermore, foliar application of Zn in the field increased grain yield and grain Zn concentration under both adequate water supply and rain-fed conditions. Zn plays a role in alleviating wheat plant drought stress by Zn-mediated increase in photosynthesis pigment and active oxygen scavenging substances, and reduction in lipid peroxidation. Furthermore, Zn fertilizer could regulate multiple antioxidant defense systems at the transcriptional level in response to drought.

  10. Mechanisms Underlying the Antidepressant Response and Treatment Resistance

    Directory of Open Access Journals (Sweden)

    Marjorie Rose Levinstein

    2014-06-01

    Full Text Available Depression is a complex and heterogeneous disorder affecting millions of Americans. There are several different medications and other treatments that are available and effective for many patients with depression. However, a substantial percentage of patients fail to achieve remission with these currently available interventions, and relapse rates are high. Therefore, it is necessary to determine both the mechanisms underlying the antidepressant response and the differences between responders and non-responders to treatment. Delineation of these mechanisms largely relies on experiments that utilize animal models. Therefore, this review provides an overview of the various mouse models that are currently used to assess the antidepressant response, such as chronic mild stress, social defeat, and chronic corticosterone. We discuss how these mouse models can be used to advance our understanding of the differences between responders and non-responders to antidepressant treatment. We also provide an overview of experimental treatment modalities that are used for treatment-resistant depression, such as deep brain stimulation and ketamine administration. We will then review the various genetic polymorphisms and transgenic mice that display resistance to antidepressant treatment. Finally, we synthesize the published data to describe a potential neural circuit underlying the antidepressant response and treatment resistance.

  11. Trichoderma-Plant Root Colonization: Escaping Early Plant Defense Responses and Activation of the Antioxidant Machinery for Saline Stress Tolerance

    OpenAIRE

    Brotman, Yariv; Landau, Udi; Cuadros-Inostroza, ?lvaro; Takayuki, Tohge; Fernie, Alisdair R.; Chet, Ilan; Viterbo, Ada; Willmitzer, Lothar

    2013-01-01

    Trichoderma spp. are versatile opportunistic plant symbionts which can colonize the apoplast of plant roots. Microarrays analysis of Arabidopsis thaliana roots inoculated with Trichoderma asperelloides T203, coupled with qPCR analysis of 137 stress responsive genes and transcription factors, revealed wide gene transcript reprogramming, proceeded by a transient repression of the plant immune responses supposedly to allow root colonization. Enhancement in the expression of WRKY18 and WRKY40, wh...

  12. Leaf miner incidence in coffee plants under different drip irrigation regimes and planting densities

    OpenAIRE

    Assis,Gleice Aparecida; Assis,Franscinely Aparecida; Scalco,Myriane Stella; Parolin,Francisco José Toloza; Fidelis,Iraci; Moraes,Jair Campos; Guimarães,Rubens José

    2012-01-01

    The objective of this work was to evaluate the effect of different drip irrigation regimes and planting densities on the incidence of the leaf miner, Leucoptera coffeella, in arabica coffee plants for one year. The experiment was carried out in 2008, in a complete randomized block design, in a split-plot in time arrangement, with four replicates. The treatments consisted of four drip irrigation regimes - soil water balance, irrigations at 20 and 60 kPa soil tensions, and a nonirrigated treatm...

  13. Seismic response analysis of floating nuclear power plant

    International Nuclear Information System (INIS)

    Hagiwara, Yutaka; Nakamura, Hideharu; Shiojiri, Hiroo

    1988-01-01

    Since Floating Nuclear Power Plants (FNPs) are considered to be isolated from horizontal seismic motion, it is anticipated to reduce seismic load for plant components and buildings on the barge. On the other hand, barge oscillation and sloshing in the closed basin might be excited by earthquakes, because natural periods of those motions correspond to relatively-long period component (between 2 and 20 seconds) of seismic motion. Therefore, it is necessary to evaluate seismic isolation effects and barge oscillation, for the rational design of FNPs. However, there do not exist any reasonable analytical tools which can evaluate seismic response of floating structures in closed basin. The purpose of the present report is to develop a seismic analysis method for FNPs. The proposed method is based on the finite element method, and the formulation includes fluid-structure interaction, water surface wave, buoyancy effect, and non-linear characteristics of mooring system. Response analysis can be executed in both time-domain and frequency-domain. Shaking table tests were conducted to validate the proposed method of analysis. The test results showed significant isolation effect of floating structure, and apparent interaction between the barge and the basin. And 2-D and 3-D frequency domain analyses and the 2-D linear and non-linear time-domain analyses were done and those analyses could simulate the test results well. (author)

  14. Implications of endophyte-plant crosstalk in light of quorum responses for plant biotechnology.

    Science.gov (United States)

    Kusari, Parijat; Kusari, Souvik; Spiteller, Michael; Kayser, Oliver

    2015-07-01

    Quorum sensing, the cell-to-cell communication system mediated by autoinducers, is responsible for regulation of virulence factors, infections, invasion, colonization, biofilm formation, and antibiotic resistance within bacterial populations. Concomitantly, quorum quenching is a process that involves attenuation of virulence factors by inhibiting or degrading quorum signaling autoinducers. Survival of endophytic microorganisms, commonly known as endophytes, in planta is a continuous mêlée with invading pathogens and pests. In order to survive in their microhabitats inside plants, endophytes have co-evolved to not only utilize an arsenal of biologically active defense compounds but also impede communication between invading pathogens. Such antivirulence strategies prevent pathogens from communicating with or recognizing each other and thus, colonizing plants. The quenching phenomena often involves microbial crosstalk within single or mixed population(s) vis-à-vis gene expression, and production/modulation of quenching enzymes coupled to various antagonistic and synergistic interactions. This concept is particularly interesting because it can be biotechnologically translated in the future to quorum inhibiting antivirulence therapies without triggering resistance in bacteria, which is currently a major problem worldwide that cannot be tackled only with antimicrobial therapies. In this mini-review, we highlight the quorum quenching capacity of endophytes with respect to attenuation of virulence factors and aiding in plant defense response. Further, benefits and potential challenges of using such systems in biotechnology are discussed.

  15. Genetic Parameters And Selection Response For Yield Traits In Bread Wheat Under Irrigated And Rainfed Environments

    Science.gov (United States)

    Khalil, Iftikhar Hussain; at-ur-Rahman, Hiday; Khan, Imran

    2008-01-01

    A set of 22 F5:7 experimental wheat lines along with four check cultivars (Dera-98, Fakhr-e-Sarhad, Ghaznavi-98 and Tatara) were evaluated as independent experiments under irrigated and rainfed environments using a randomized complete block design at NWFP Agricultural University, Peshawar during 2004-05. The two environments were statistically different for days to heading and spike length only. Highly significant genetic variability existed among the wheat lines (P<0.01) in the combined analysis across environments for all traits. Genotype×environment interactions were non-significant for all traits except 1000-grain weight indicating consistent performance of wheat genotypes across the two environments. Wheat lines and check cultivars were 2 to 5 days early in heading under rainfed environment compared to the irrigated. Plant height, spike length, 1000-grain weight, biological and grain yields were generally reduced under rainfed environment. Genetic variances were of greater magnitude than environmental variances for most of the traits in both environments. The heritability estimates were of higher magnitude (0.74 to 0.96) for days to heading, plant height, spike length, biological and grain yield, while medium (0.31 to 0.51) for 1000-grain weight. Selection differentials were negative for heading (-7.3 days in irrigated vs -9.4 days in rainfed) and plant height (-9.0 cm in irrigated vs -8.7 cm in rainfed) indicating possibility of selecting wheat genotypes with early heading and short plant stature. Positive selection differentials of 1.3 vs 1.6 cm for spike length, 3.8 vs 3.4 g for 1000-grain weight, 2488.2 vs 3139.7 kg ha-1 for biological yield and 691.6 vs 565.4 kg ha-1 for grain yield at 20% selection intensity were observed under irrigated and rainfed environments, respectively. Expected selection responses were 7.98 vs 8.91 days for heading, 8.20 vs 9.52 cm for plant height, 1.01 vs 1.61 cm for spike length, 2.12 vs 1.15 g for 1000-grain weight, 1655

  16. Growth, essential oil content, and content of coumarin in young plants of guaco (Mikania glomerata Sprengel cultivated under colored nets

    Directory of Open Access Journals (Sweden)

    Girlene Santos Souza

    2011-09-01

    Full Text Available Mikania glomerata Sprengel is a medicinal plant widely used in folk medicine, mainly to treat respiratory disorders, which acts by dilating the bronchi, being coumarin one of the substances associated with this effect. Therefore, understanding the physiological behavior of this species and its responses to the environmental conditions is necessary to improve the cultivation methods. In this context, the aim of this work was to evaluate the effect of light spectrum control on growth, the essential oil content, and the content of coumarin in Mikania glomerata Sprengel. Plants were grown for four months under nets with 50% shading in gray, red, blue, and exposed to full sunlight (0%. The essential oil was extracted from fresh leaves through hydrodistillation in a modified Clevenger apparatus. The identification and quantification of coumarin were performed through high performance liquid chromatography (HPLC. The results showed the blue fabric allowed an increase in total dry matter accumulation and leaf area, as plants under red shading presented higher dry matter allocation to the roots. The smallest quantity of dry leaves was observed in plants grown under full sun exposure. Changes were not observed, however, in leaf weight ratio and in root/shoot proportion. The essential oil content of plants grown under blue net was 0.14%, which corresponded to an increase of 142% over the level found in plants grown under full sun exposure, as the coumarin content was not influenced by the net color. These results show that light can be modulated during cultivation, in order to obtain desirable morphological characteristics and maximize the production of active principles in this species.

  17. Abiotic Stress Responses and Microbe-Mediated Mitigation in Plants: The Omics Strategies

    Science.gov (United States)

    Meena, Kamlesh K.; Sorty, Ajay M.; Bitla, Utkarsh M.; Choudhary, Khushboo; Gupta, Priyanka; Pareek, Ashwani; Singh, Dhananjaya P.; Prabha, Ratna; Sahu, Pramod K.; Gupta, Vijai K.; Singh, Harikesh B.; Krishanani, Kishor K.; Minhas, Paramjit S.

    2017-01-01

    Abiotic stresses are the foremost limiting factors for agricultural productivity. Crop plants need to cope up adverse external pressure created by environmental and edaphic conditions with their intrinsic biological mechanisms, failing which their growth, development, and productivity suffer. Microorganisms, the most natural inhabitants of diverse environments exhibit enormous metabolic capabilities to mitigate abiotic stresses. Since microbial interactions with plants are an integral part of the living ecosystem, they are believed to be the natural partners that modulate local and systemic mechanisms in plants to offer defense under adverse external conditions. Plant-microbe interactions comprise complex mechanisms within the plant cellular system. Biochemical, molecular and physiological studies are paving the way in understanding the complex but integrated cellular processes. Under the continuous pressure of increasing climatic alterations, it now becomes more imperative to define and interpret plant-microbe relationships in terms of protection against abiotic stresses. At the same time, it also becomes essential to generate deeper insights into the stress-mitigating mechanisms in crop plants for their translation in higher productivity. Multi-omics approaches comprising genomics, transcriptomics, proteomics, metabolomics and phenomics integrate studies on the interaction of plants with microbes and their external environment and generate multi-layered information that can answer what is happening in real-time within the cells. Integration, analysis and decipherization of the big-data can lead to a massive outcome that has significant chance for implementation in the fields. This review summarizes abiotic stresses responses in plants in-terms of biochemical and molecular mechanisms followed by the microbe-mediated stress mitigation phenomenon. We describe the role of multi-omics approaches in generating multi-pronged information to provide a better understanding

  18. ISOLATION OF MESOPHYLL PROTOPLASTS FROM MEDITERRANEAN WOODY PLANTS FOR THE STUDY OF DNA INTEGRITY UNDER ABIOTIC STRESS

    Directory of Open Access Journals (Sweden)

    Elena Kuzminsky

    2016-08-01

    Full Text Available Abiotic stresses have considerable negative impact on Mediterranean plant ecosystems and better comprehension of the genetic control of response and adaptation of trees to global changes is urgently needed. The Single Cell Gel Electrophoresis assay could be considered a good estimator of DNA damage in an individual eukaryotic cell. This method has been mainly employed in animal tissues, because the plant cell wall represents an obstacle for the extraction of nuclei; moreover, in Mediterranean woody species, especially in the sclerophyll plants, this procedure can be quite difficult because of the presence of sclerenchyma and hardened cells. On the other hand, these plants represent an interesting material to be studied because of the ability of these plants to tolerate abiotic stress. For instance, holm oak (Quercus ilex L. has been selected as the model plant to identify critical levels of O3 for Southern European forests. Consequently, a quantitative method for the evaluation of cell injury of leaf tissues of this species is required. Optimal conditions for high-yield nuclei isolation were obtained by using protoplast technology and a detailed description of the method is provided and discussed. White poplar (Populus alba L. was used as an internal control for protoplast isolation. Such a method has not been previously reported in newly fully developed leaves of holm oak. This method combined with Single Cell Gel Electrophoresis assay represents a new tool for testing the DNA integrity of leaf tissues in higher plants under stress conditions.

  19. Hydrodynamic response of viscous fluids under seismic excitation

    International Nuclear Information System (INIS)

    Ma, D.C.

    1993-01-01

    Hydrodynamic response of liquid-tank systems, such as reactor vessels, spent-fuel pools and liquid storage tanks have been studied extensively in the last decade (Chang et al. 1988; Ma et al. 1991). However, most of the studies are conducted with the assumption of an inviscid fluid. In recent years, the hydrodynamic response of viscous fluids has received increasing attention in high level waste storage tanks containing viscous waste material. This paper presents a numerical study on the hydrodynamic response of viscous fluids in a large 2-D fluid-tank system under seismic excitation. Hydrodynamic responses (i.e. sloshing wave height, fluid pressures, shear stress, etc.) are calculated for a fluid with various viscosities. Four fluid viscosities are considered. They are 1 cp, 120 cp, 1,000 cp and 12,000 cp (1 cp = 1.45 x 10 -7 lb-sec/in 2 ). Note that the liquid sodium of the Liquid-Metal Reactor (LMR) reactor has a viscosity of 1.38 x 10 -5 lb-sec/in 2 (about 95 cp) at an operational temperature of 900 degree F. Section 2 describes the pertinent features of the mathematical model. In Section 3, the fundamental sloshing phenomena of viscous fluid are examined. Sloshing wave height and shear stress for fluid with different viscosities are compared. The conclusions are given in Section 4

  20. Do competitors modulate rare plant response to precipitation change?

    Science.gov (United States)

    Levine, J.M.; Kathryn, Mceachern A.; Cowan, C.

    2010-01-01

    Ecologists increasingly suspect that climate change will directly impact species physiology, demography, and phenology, but also indirectly affect these measures via changes to the surrounding community. Unfortunately, few studies examine both the direct and indirect pathways of impact. Doing so is important because altered competitive pressures can reduce or magnify the direct responses of a focal species to climate change. Here, we examine the effects of changing rainfall on three rare annual plant species in the presence and absence of competition on the California Channel Islands. We used rain-out shelters and hand watering to exclude and augment early, late, and season-long rainfall, spanning the wide range of precipitation change forecast for the region. In the absence of competition, droughts reduced the population growth rates of two of three focal annuals, while increased rainfall was only sometimes beneficial, As compared to the focal species, the dominant competitors were more sensitive to the precipitation treatments, benefiting from increased season-long precipitation and harmed by droughts. Importantly, the response of two of three competitors to the precipitation treatments tended to be positively correlated with those of the focal annuals. Although this leads to the expectation that increased competition will counter the direct benefits of favorable conditions, such indirect effects of precipitation change proved weak to nonexistent in our experiment. Competitors had little influence on the precipitation response of two focal species, due to their low sensitivity to competition and highly variable precipitation responses. Competition did affect how our third focal species responded to precipitation change, but this effect only approached significance, and whether it truly resulted from competitor response to precipitation change was unclear. Our work suggests that even when competitors respond to climate change, these responses may have little

  1. Halophytic Companion Plants Improve Growth and Physiological Parameters of Tomato Plants Grown under Salinity

    International Nuclear Information System (INIS)

    Karakas, S.; Cullu, M. A.; Kaya, C.; Dikilitas, M.

    2016-01-01

    Salinity becomes a major concern when soil salt concentration becomes excessive in growth medium. Halophytes are capable of accumulating high concentrations of NaCl in their tissues, thus using halophytic plants in crop rotations or even in mixed cropping systems may be a promising management practices to mitigate salt stress related yield loses. Salinity induced yield losses and related physiological parameters on tomato plants (Lycopersicon esculentum Mill. cv. SC2121) grown with or without halophytic companion plants (SalsolasodaL. and Portulacaoleracea L.) were investigated in pot experiment. Treatments consist of four soil type (collected from Harran plain-Turkey) with similar physical properties but varying in salinity level: electrical conductivity (EC): 0.9, 4.2, 7.2, and 14.1 dS m/sup -1/. The reduction in plant total dry weight was 24, 19, and 48 percent in soils with slight (4.2dS m/sup -1/), moderate (7.2 dS m/sup -1/) and high (14.1 dS m/sup -1/) salinity as compared to non-saline soil (0.9 dS m/sup -1/), respectively. Leaf content of proline, malondialdehyde (MDA), catalase (CAT) and peroxidase (POX) enzyme activity increased with increasing level of salinity. In tomato plants grown in consociation with Salsolasoda, salinity induced DM decrease was only 6, 12 and 28% in soils with slight, moderate and high salinity as compared to non-saline soil, respectively. However, when Portulaca oleracea used as companion plant, no significant change in biomass or fruit yield was observed. This study showed that mixed planting with Salsolasodain high saline soils may be an effective phyto-remediation technique that may secure yield formation and quality of tomato. (author)

  2. Phosphorene under strain:electronic, mechanical and piezoelectric responses

    Science.gov (United States)

    Drissi, L. B.; Sadki, S.; Sadki, K.

    2018-01-01

    Structural, electronic, elastic and piezoelectric properties of pure phosphorene under in-plane strain are investigated using first-principles calculations based on density functional theory. The two critical yielding points are determined along armchair and zigzag directions. It is shown that the buckling, the band gap and the charge transfer can be controlled under strains. A semiconductor to metallic transition is observed in metastable region. Polar plots of Young's modulus, Poisson ratio, sound velocities and Debye temperature exhibit evident anisotropic feature of phosphorene and indicate auxetic behavior for some angles θ. Our calculations show also that phosphorene has both in-plane and out-of-plane piezoelectric responses comparable to known 2D materials. The findings of this work reveal the great potential of pure phosphorene in nanomechanical applications.

  3. The tank's dynamic response under nuclear explosion blast wave

    International Nuclear Information System (INIS)

    Xu Mei; Wang Lianghou; Li Xiaotian; Yu Suyuan; Zhang Zhengming; Wan Li

    2005-01-01

    To weapons and equipment, blast wave is the primary destructive factor. In this paper, taken the real model-59 tank as an example, we try to transform the damage estimation problem into computing a fluid structure interaction problem with finite element method. The response of tank under nuclear explosion blast wave is computed with the general-coupling algorithm. Also, the dynamical interaction of blast wave and tank is reflected in real time. The deformation of each part of the tank is worked out and the result corresponds to the real-measured data. (authors)

  4. Wind turbine aerodynamic response under atmospheric icing conditions

    DEFF Research Database (Denmark)

    Etemaddar, M.; Hansen, Martin Otto Laver; Moan, T.

    2014-01-01

    -four hours of icing, with time varying wind speed and atmospheric icing conditions, was simulated on a rotor. Computational fluid dynamics code, FLUENT, was used to estimate the aerodynamic coefficients of the blade after icing. The results were also validated against wind tunnel measurements performed at LM...... Wind Power using a NACA64618 airfoil. The effects of changes in geometry and surface roughness are considered in the simulation. A blade element momentum code WT-Perf is then used to quantify the degradation in performance curves. The dynamic responses of the wind turbine under normal and iced...

  5. Analysis of Network Topologies Underlying Ethylene Growth Response Kinetics.

    Science.gov (United States)

    Prescott, Aaron M; McCollough, Forest W; Eldreth, Bryan L; Binder, Brad M; Abel, Steven M

    2016-01-01

    Most models for ethylene signaling involve a linear pathway. However, measurements of seedling growth kinetics when ethylene is applied and removed have resulted in more complex network models that include coherent feedforward, negative feedback, and positive feedback motifs. The dynamical responses of the proposed networks have not been explored in a quantitative manner. Here, we explore (i) whether any of the proposed models are capable of producing growth-response behaviors consistent with experimental observations and (ii) what mechanistic roles various parts of the network topologies play in ethylene signaling. To address this, we used computational methods to explore two general network topologies: The first contains a coherent feedforward loop that inhibits growth and a negative feedback from growth onto itself (CFF/NFB). In the second, ethylene promotes the cleavage of EIN2, with the product of the cleavage inhibiting growth and promoting the production of EIN2 through a positive feedback loop (PFB). Since few network parameters for ethylene signaling are known in detail, we used an evolutionary algorithm to explore sets of parameters that produce behaviors similar to experimental growth response kinetics of both wildtype and mutant seedlings. We generated a library of parameter sets by independently running the evolutionary algorithm many times. Both network topologies produce behavior consistent with experimental observations, and analysis of the parameter sets allows us to identify important network interactions and parameter constraints. We additionally screened these parameter sets for growth recovery in the presence of sub-saturating ethylene doses, which is an experimentally-observed property that emerges in some of the evolved parameter sets. Finally, we probed simplified networks maintaining key features of the CFF/NFB and PFB topologies. From this, we verified observations drawn from the larger networks about mechanisms underlying ethylene

  6. Analysis of Network Topologies Underlying Ethylene Growth Response Kinetics

    Directory of Open Access Journals (Sweden)

    Aaron M. Prescott

    2016-08-01

    underlying ethylene signaling. Analysis of each network topology results in predictions about changes that occur in network components that can be experimentally tested to give insights into which, if either, network underlies ethylene responses.

  7. Arbuscular mycorrhizal symbiosis influences strigolactone production under salinity and alleviates salt stress in lettuce plants.

    Science.gov (United States)

    Aroca, Ricardo; Ruiz-Lozano, Juan Manuel; Zamarreño, Angel María; Paz, José Antonio; García-Mina, José María; Pozo, María José; López-Ráez, Juan Antonio

    2013-01-01

    Arbuscular mycorrhizal (AM) symbiosis can alleviate salt stress in plants. However the intimate mechanisms involved, as well as the effect of salinity on the production of signalling molecules associated to the host plant-AM fungus interaction remains largely unknown. In the present work, we have investigated the effects of salinity on lettuce plant performance and production of strigolactones, and assessed its influence on mycorrhizal root colonization. Three different salt concentrations were applied to mycorrhizal and non-mycorrhizal plants, and their effects, over time, analyzed. Plant biomass, stomatal conductance, efficiency of photosystem II, as well as ABA content and strigolactone production were assessed. The expression of ABA biosynthesis genes was also analyzed. AM plants showed improved growth rates and a better performance of physiological parameters such as stomatal conductance and efficiency of photosystem II than non-mycorrhizal plants under salt stress since very early stages - 3 weeks - of plant colonization. Moreover, ABA levels were lower in those plants, suggesting that they were less stressed than non-colonized plants. On the other hand, we show that both AM symbiosis and salinity influence strigolactone production, although in a different way in AM and non-AM plants. The results suggest that AM symbiosis alleviates salt stress by altering the hormonal profiles and affecting plant physiology in the host plant. Moreover, a correlation between strigolactone production, ABA content, AM root colonization and salinity level is shown. We propose here that under these unfavourable conditions, plants increase strigolactone production in order to promote symbiosis establishment to cope with salt stress. Copyright © 2012 Elsevier GmbH. All rights reserved.

  8. Exertional rhabdomyolysis: physiological response or manifestation of an underlying myopathy?

    Science.gov (United States)

    Scalco, Renata S; Snoeck, Marc; Quinlivan, Ros; Treves, Susan; Laforét, Pascal; Jungbluth, Heinz; Voermans, Nicol C

    2016-01-01

    Exertional rhabdomyolysis is characterised by muscle breakdown associated with strenuous exercise or normal exercise under extreme circumstances. Key features are severe muscle pain and sudden transient elevation of serum creatine kinase (CK) levels with or without associated myoglobinuria. Mild cases may remain unnoticed or undiagnosed. Exertional rhabdomyolysis is well described among athletes and military personnel, but may occur in anybody exposed to unaccustomed exercise. In contrast, exertional rhabdomyolysis may be the first manifestation of a genetic muscle disease that lowers the exercise threshold for developing muscle breakdown. Repeated episodes of exertional rhabdomyolysis should raise the suspicion of such an underlying disorder, in particular in individuals in whom the severity of the rhabdomyolysis episodes exceeds the expected response to the exercise performed. The present review aims to provide a practical guideline for the acute management and postepisode counselling of patients with exertional rhabdomyolysis, with a particular emphasis on when to suspect an underlying genetic disorder. The pathophysiology and its clinical features are reviewed, emphasising four main stepwise approaches: (1) the clinical significance of an acute episode, (2) risks of renal impairment, (3) clinical indicators of an underlying genetic disorders and (4) when and how to recommence sport activity following an acute episode of rhabdomyolysis. Genetic backgrounds that appear to be associated with both enhanced athletic performance and increased rhabdomyolysis risk are briefly reviewed. PMID:27900193

  9. Plant–plant interactions mediate the plastic and genotypic response of Plantago asiatica to CO2: an experiment with plant populations from naturally high CO2 areas

    Science.gov (United States)

    van Loon, Marloes P.; Rietkerk, Max; Dekker, Stefan C.; Hikosaka, Kouki; Ueda, Miki U.; Anten, Niels P. R.

    2016-01-01

    Background and Aims The rising atmospheric CO2 concentration ([CO2]) is a ubiquitous selective force that may strongly impact species distribution and vegetation functioning. Plant–plant interactions could mediate the trajectory of vegetation responses to elevated [CO2], because some plants may benefit more from [CO2] elevation than others. The relative contribution of plastic (within the plant’s lifetime) and genotypic (over several generations) responses to elevated [CO2] on plant performance was investigated and how these patterns are modified by plant–plant interactions was analysed. Methods Plantago asiatica seeds originating from natural CO2 springs and from ambient [CO2] sites were grown in mono stands of each one of the two origins as well as mixtures of both origins. In total, 1944 plants were grown in [CO2]-controlled walk-in climate rooms, under a [CO2] of 270, 450 and 750 ppm. A model was used for upscaling from leaf to whole-plant photosynthesis and for quantifying the influence of plastic and genotypic responses. Key Results It was shown that changes in canopy photosynthesis, specific leaf area (SLA) and stomatal conductance in response to changes in growth [CO2] were mainly determined by plastic and not by genotypic responses. We further found that plants originating from high [CO2] habitats performed better in terms of whole-plant photosynthesis, biomass and leaf area, than those from ambient [CO2] habitats at elevated [CO2] only when both genotypes competed. Similarly, plants from ambient [CO2] habitats performed better at low [CO2], also only when both genotypes competed. No difference in performance was found in mono stands. Conclusion The results indicate that natural selection under increasing [CO2] will be mainly driven by competitive interactions. This supports the notion that plant–plant interactions have an important influence on future vegetation functioning and species distribution. Furthermore, plant performance was mainly

  10. Homeostatic response to hypoxia is regulated by the N-end rule pathway in plants.

    Science.gov (United States)

    Gibbs, Daniel J; Lee, Seung Cho; Isa, Nurulhikma Md; Gramuglia, Silvia; Fukao, Takeshi; Bassel, George W; Correia, Cristina Sousa; Corbineau, Françoise; Theodoulou, Frederica L; Bailey-Serres, Julia; Holdsworth, Michael J

    2011-10-23

    Plants and animals are obligate aerobes, requiring oxygen for mitochondrial respiration and energy production. In plants, an unanticipated decline in oxygen availability (hypoxia), as caused by roots becoming waterlogged or foliage submergence, triggers changes in gene transcription and messenger RNA translation that promote anaerobic metabolism and thus sustain substrate-level ATP production. In contrast to animals, oxygen sensing has not been ascribed to a mechanism of gene regulation in response to oxygen deprivation in plants. Here we show that the N-end rule pathway of targeted proteolysis acts as a homeostatic sensor of severe low oxygen levels in Arabidopsis, through its regulation of key hypoxia-response transcription factors. We found that plants lacking components of the N-end rule pathway constitutively express core hypoxia-response genes and are more tolerant of hypoxic stress. We identify the hypoxia-associated ethylene response factor group VII transcription factors of Arabidopsis as substrates of this pathway. Regulation of these proteins by the N-end rule pathway occurs through a characteristic conserved motif at the amino terminus initiating with Met-Cys. Enhanced stability of one of these proteins, HRE2, under low oxygen conditions improves hypoxia survival and reveals a molecular mechanism for oxygen sensing in plants via the evolutionarily conserved N-end rule pathway. SUB1A-1, a major determinant of submergence tolerance in rice, was shown not to be a substrate for the N-end rule pathway despite containing the N-terminal motif, indicating that it is uncoupled from N-end rule pathway regulation, and that enhanced stability may relate to the superior tolerance of Sub1 rice varieties to multiple abiotic stresses. © 2011 Macmillan Publishers Limited. All rights reserved

  11. The role of silicon in physiology of the medicinal plant (Lonicera japonica L.) under salt stress

    OpenAIRE

    Gengmao, Zhao; Shihui, Li; Xing, Sun; Yizhou, Wang; Zipan, Chang

    2015-01-01

    Silicon(Si) is the only element which can enhance the resistance to multiple stresses. However, the role of silicon in medicinal plants under salt stress is not yet understood. This experiment was conducted to study the effects of silicon addition on the growth, osmotic adjustments, photosynthetic characteristics, chloroplast ultrastructure and Chlorogenic acid (CGA) production of Honeysuckle plant (Lonicera japonica L.) under salt-stressed conditions. Salinity exerted an adverse effect on th...

  12. Physiological behaviors and recovery responses of four galician grapevine (Vitis vinifera L. cultivars under water stress

    Directory of Open Access Journals (Sweden)

    Islam M. T.

    2012-11-01

    Full Text Available Gas exchange parameters and chlorophyll fluorescence of four pot grown Galician grapevines (Vitis vinifera L. cv. Albariño, Brancellao, Godello and Treixadura were examined under different levels of water stress in greenhouse. After extreme stress, gas exchange recovery responses were evaluated. Average ΨPD for control and stressed plants were -0.4MPa and -1.45MPa respectively. All varieties showed gradual declining of all gas exchange parameters (gs, E and A with increasing of stress periods. Under stressed conditions, Albariño and Godello showed higher CO2 assimilation rate. At the end of stress period leaf defoliation was found in Albariño and Brancellao. Gas exchange recovery was higher for both Godello and Treixadura. A better response of auxiliary bud recovery was present in Albariño than in Brancellao. Close correlations between water stress and gas exchange parameters were found and it varies on genotype. Albariño, Godello and Treixadura followed same diurnal patterns of gas exchange rate for control and stressed plant respectively. Diurnal pattern of CO2 assimilation rate of all tested varieties followed gs and E. Only Brancellao showed treatment effect on mid-day Fv/Fm. Among four varieties photoinhibition was only found in Brancellao. At stressed condition physiological responses of grapevines were genotype depended.

  13. Steam generators under construction for the SNR-300 power plant

    International Nuclear Information System (INIS)

    Essebaggers, J.

    1975-01-01

    The prototype straight tube and the helical coil-steam generator has been designed and fabricated of which the straight tube steam generator has been successfully tested for over 3000 hours at prototypical conditions and is presently being dismantled for detailed examination of critical designed features. The prototype helical coil steam generator is presently under testing in the 50 MWt test facility at TNO-Hengelo with approximately 500 hours of operation at full load conditions. In an earlier presentation the design and fabrication of the prototype steam generators have been presented, while for this presentation the production units for SNR-300 will be discussed. Some preliminary information will be presented at this meeting of the dismantling operations of the prototype straight tube steam generator. (author)

  14. Response diversity of free-floating plants to nutrient stoichiometry and temperature: growth and resting body formation

    Science.gov (United States)

    2016-01-01

    Free-floating plants, like most groups of aquatic primary producers, can become nuisance vegetation under certain conditions. On the other hand, there is substantial optimism for the applied uses of free-floating plants, such as wastewater treatment, biofuel production, and aquaculture. Therefore, understanding the species-specific responses of floating plants to abiotic conditions will inform both management decisions and the beneficial applications of these plants. I measured the responses of three floating plant species common in the northeast United States (Lemna minor, Spirodela polyrhiza, and Wolffia brasiliensis) to nutrient stoichiometry (nitrogen and phosphorus) and temperature in the laboratory. I also used survey data to determine the pattern of species richness of floating plants in the field and its relationship with the dominance of this group. Floating plant species exhibited unique responses to nutrient stoichiometry and temperature in the laboratory, especially under low temperatures (18 °C) and low nutrient conditions (0.5 mg N L−1, 0.083 mg P L−1). The three species displayed an apparent tradeoff with different strategies of growth or dormancy. In the field, water bodies with three or more species of floating plants were not more frequently dominated by this group. The response diversity observed in the lab may not be associated with the dominance of this group in the field because it is masked by environmental variability, has a weak effect, or is only important during transient circumstances. Future research to develop applied uses of floating plants should examine response diversity across a greater range of species or clones and environmental conditions. PMID:26989619

  15. Observed magnified runoff response to rainfall intensification under global warming

    International Nuclear Information System (INIS)

    Huang, Jr-Chuan; Lee, Tsung-Yu; Lee, Jun-Yi

    2014-01-01

    Runoff response to rainfall intensification under global warming is crucial, but is poorly discussed due to the limited data length and human alteration. Historical rainfall and runoff records in pristine catchments in Taiwan were investigated through trend analysis and cross temperature difference analysis. Trend analysis showed that both rainfall and runoff in the 99.9-percentile have been significantly increasing in terms of frequency and intensity over the past four decades. Cross temperature difference analysis quantified that the rainfall and runoff extremes (including the 99.0–99.9-percentiles) may increase by 69.5% and 99.8%, respectively, under a future scenario of 1  ° C increase in temperature. This increase in intensity resembles the increase in intensity observed between 1971–1990 and 1991–2010. The amplified runoff response can be related to the limited catchment storage capacity being preoccupied by rainfall extremes. The quantified temperature effect on rainfall and runoff intensification can be a strong basis for designing scenarios, confirming and fusing GCMs’ results. In addition, the runoff amplification should be a warning for other regions with significant rainfall intensification. Appropriate strategies are indispensable and urgently needed to maintain and protect the development of societies. (paper)

  16. Dynamic response of multiple nanobeam system under a moving nanoparticle

    Directory of Open Access Journals (Sweden)

    Shahrokh Hosseini Hashemi

    2018-03-01

    Full Text Available In this article, nonlocal continuum based model of multiple nanobeam system (MNBS under a moving nanoparticle is investigated using Eringen’s nonlocal theory. Beam layers are assumed to be coupled by winkler elastic medium and the nonlocal Euler-Bernoulli beam theory is used to model each layer of beam. The Hamilton’s principle, Eigen function technique and the Laplace transform method are employed to solve the governing equations. Analytical solutions of the transverse displacements for MNBs with simply supported boundary condition are presented for double layered and three layered MNBSs. For higher number of layers, the governing set of equations is solved numerically and the results are presented. This study shows that small-scale parameter has a significant effect on dynamic response of MNBS under a moving nanoparticle. Sensitivity of dynamical deflection to variation of nonlocal parameter, stiffness of Winkler elastic medium and number of nanobeams are presented in nondimensional form for each layer. Keywords: Dynamic response, Analytical solution, Moving particle, Nanobeam, Multi-layered nanobeam

  17. Evolution of crop production under a pseudo-space environment using model plants, Lotus japonicus

    Science.gov (United States)

    Tomita-Yokotani, Kaori; Motohashi, Kyohei; Omi, Naomi; Sato, Seigo; Aoki, Toshio; Hashimoto, Hirofumi; Yamashita, Masamichi

    Habitation in outer space is one of our challenges. We have been studying space agriculture and/or spacecraft agriculture to provide food and oxygen for the habitation area in the space environment. However, careful investigation should be made concerning the results of exotic environmental effects on the endogenous production of biologically active substances in indi-vidual cultivated plants in a space environment. We have already reported that the production of functional substances in cultivated plants as crops are affected by gravity. The amounts of the main physiological substances in these plants grown under terrestrial control were different from that grown in a pseudo-microgravity. These results suggested that the nutrition would be changed in the plants/crops grown in the space environment when human beings eat in space. This estimation required us to investigate each of the useful components produced by each plant grown in the space environment. These estimations involved several study fields, includ-ing nutrition, plant physiology, etc. On the other hand, the analysis of model plant genomes has recently been remarkably advanced. Lotus japonicus, a leguminous plant, is also one of the model plant. The leguminosae is a large family in the plant vegetable kingdom and almost the entire genome sequence of Lotus japonicus has been determined. Nitrogen fixation would be possible even in a space environment. We are trying to determine the best conditions and evolution for crop production using the model plants.

  18. Soil P forms and P uptake under intensive plant growth in the greenhouse

    International Nuclear Information System (INIS)

    Henriquez, Carlos; Killorn, Randy

    2005-01-01

    The concentration of available soil (P) is a function of the equilibrium established among different soil P forms through numerous and different reactions in soil. The objective of this study was to examine the changes in P forms and P supply under exhaustive extraction conditions in soils from 3 different land use areas. In order to establish a greenhouse experiment, representative soil samples (0-20 cm) were taken from three fields located adjacent to one another, in a Typic Hapludands in Costa Rica. One field was a coffee plantation (Coffea arabica var Catuai), the second a sugar cane plantation (Saccarum spp. var 611721), and the third a secondary forest. Sorghum bicolor var Glazer 41) was planted in 1-liter pots and harvested 4 times consecutively. Treatments were no P and P application (100 mg kg -1 ) for each of the different land-use soil samples. Shoot and root dry matter and total P uptake were determined. Soil samples were taken before and after each of the 4 plant growth cycles and analyzed using a modified Hedley et al. (1982) soil P fractionation methodology. Labile-Pi, NaOH-Pi, HCI-Pi, extractable-Po, and residual -P were determined. Applied P increased labile-Pi, NaOH-Pi and HCI-Pi. Statistical changes were not observed in extractable organic P and residual-P due to P application. The NaOH-Pi and HCI-Pi seemed to act as a temporary pool of applied P. The possible participation of residual-P in replenishment of labile-P and NaOH-Pi was observed. The amount of plant P untake was closely related to the initial amount of labile-Pi and was higher in coffee than in forest and sugar cane soils. The labile-P was depleted by plant uptake. Rapid changes in reversibly available soil P forms (NaOH-Pi and HCI-Pi) were observed during the experiment. Our results suggest the occurrence of very rapid and dynamic changes between available and unavailable soil P forms in response to fertilizer application and plant uptake, supporting the idea of a continuum among the

  19. Recent Advances in Plant Early Signaling in Response to Herbivory

    Directory of Open Access Journals (Sweden)

    Gen-Ichiro Arimura

    2011-06-01

    Full Text Available Plants are frequently attacked by herbivores and pathogens and therefore have acquired constitutive and induced defenses during the course of their evolution. Here we review recent progress in the study of the early signal transduction pathways in host plants in response to herbivory. The sophisticated signaling network for plant defense responses is elicited and driven by both herbivore-induced factors (e.g., elicitors, effectors, and wounding and plant signaling (e.g., phytohormone and plant volatiles in response to arthropod factors. We describe significant findings, illuminating the scenario by providing broad insights into plant signaling involved in several arthropod-host interactions.

  20. Whole plant acclimation responses by finger millet to low nitrogen stress

    Directory of Open Access Journals (Sweden)

    Travis Luc Goron

    2015-08-01

    Full Text Available The small grain cereal, finger millet (FM, Eleusine coracana L. Gaertn, is valued by subsistence farmers in India and East Africa as a low-input crop. It is reported by farmers to require no added nitrogen, or only residual N, to produce grain. Exact mechanisms underlying the acclimation responses of FM to low N are largely unknown, both above and below ground. In particular, the responses of FM roots and root hairs to N or any other nutrient have not previously been reported. Given its low N requirement, FM also provides a rare opportunity to study long-term responses to N starvation in a cereal. The objective of this study was to survey the shoot and root morphometric responses of FM, including root hairs, to low N stress. Plants were grown in pails in a semi-hydroponic system on clay containing extremely low background N, supplemented with N or no N. To our surprise, plants grown without deliberately added N grew to maturity, looked relatively normal and produced healthy seed heads. Plants responded to the low N treatment by decreasing shoot, root and seed head biomass. These declines under low N were associated with decreased shoot tiller number, crown root number, total crown root length and total lateral root length, but with no consistent changes in root hair traits. Changes in tiller and crown root number appeared to coordinate the above and below ground acclimation responses to N. We discuss the remarkable ability of FM to grow to maturity without deliberately added N. The results suggest that FM should be further explored to understand this trait. Our observations are consistent with indigenous knowledge from subsistence farmers in Africa and Asia that this crop can survive extreme environments.

  1. Whole plant acclimation responses by finger millet to low nitrogen stress.

    Science.gov (United States)

    Goron, Travis L; Bhosekar, Vijay K; Shearer, Charles R; Watts, Sophia; Raizada, Manish N

    2015-01-01

    The small grain cereal, finger millet (FM, Eleusine coracana L. Gaertn), is valued by subsistence farmers in India and East Africa as a low-input crop. It is reported by farmers to require no added nitrogen (N), or only residual N, to produce grain. Exact mechanisms underlying the acclimation responses of FM to low N are largely unknown, both above and below ground. In particular, the responses of FM roots and root hairs to N or any other nutrient have not previously been reported. Given its low N requirement, FM also provides a rare opportunity to study long-term responses to N starvation in a cereal species. The objective of this study was to survey the shoot and root morphometric responses of FM, including root hairs, to low N stress. Plants were grown in pails in a semi-hydroponic system on clay containing extremely low background N, supplemented with N or no N. To our surprise, plants grown without deliberately added N grew to maturity, looked relatively normal and produced healthy seed heads. Plants responded to the low N treatment by decreasing shoot, root, and seed head biomass. These declines under low N were associated with decreased shoot tiller number, crown root number, total crown root length and total lateral root length, but with no consistent changes in root hair traits. Changes in tiller and crown root number appeared to coordinate the above and below ground acclimation responses to N. We discuss the remarkable ability of FM to grow to maturity without deliberately added N. The results suggest that FM should be further explored to understand this trait. Our observations are consistent with indigenous knowledge from subsistence farmers in Africa and Asia, where it is reported that this crop can survive extreme environments.

  2. Strigolactone regulates anthocyanin accumulation, acid phosphatases production and plant growth under low phosphate condition in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Shinsaku Ito

    Full Text Available Phosphate is an essential macronutrient in plant growth and development; however, the concentration of inorganic phosphate (Pi in soil is often suboptimal for crop performance. Accordingly, plants have developed physiological strategies to adapt to low Pi availability. Here, we report that typical Pi starvation responses in Arabidopsis are partially dependent on the strigolactone (SL signaling pathway. SL treatment induced root hair elongation, anthocyanin accumulation, activation of acid phosphatase, and reduced plant weight, which are characteristic responses to phosphate starvation. Furthermore, the expression profile of SL-response genes correlated with the expression of genes induced by Pi starvation. These results suggest a potential overlap between SL signaling and Pi starvation signaling pathways in plants.

  3. Effect of support conditions on structural response under dynamic loading

    International Nuclear Information System (INIS)

    Akram, T.; Memon, S.A.

    2008-01-01

    In design practice, dynamic structural analysis is carried out with base of structure considered as fixed; this means that foundation is placed on rock like soil material. While conducting this type of analyses the role of foundation and soil behaviour is totally neglected. The actions in members and loads transferred at foundation level obtained in this manner do not depict the true structural behaviour. FEM (Finite Element Methods) analysis where both superstructure and foundation soil are coupled together is quite complicated and expensive for design environments. A simplified model is required to depict dynamic response of structures with foundations based on flexible soils. The primary purpose of this research is to compare the superstructure dynamic responses of structural systems with fixed base to that of simple soil model base. The selected simple soil model is to be suitable for use in a design environment to give more realistic results. For this purpose building models are idealized with various heights and structural systems in both 2D (Two Dimensional) and 3D (Three Dimensional) space. These models are then provided with visco-elastic supports representing three soil bearing capacities and the analysis results are compared to that of fixed supports models. The results indicate that fixed support system underestimates natural time period of the structures. Dynamic behavior and force response of visco-elastic support is different from fixed support model. Fixed support models result in over designed base columns and under designed beams. (author)

  4. Dynamical anisotropic response of black phosphorus under magnetic field

    Science.gov (United States)

    Liu, Xuefeng; Lu, Wei; Zhou, Xiaoying; Zhou, Yang; Zhang, Chenglong; Lai, Jiawei; Ge, Shaofeng; Sekhar, M. Chandra; Jia, Shuang; Chang, Kai; Sun, Dong

    2018-04-01

    Black phosphorus (BP) has emerged as a promising material candidate for next generation electronic and optoelectronic devices due to its high mobility, tunable band gap and highly anisotropic properties. In this work, polarization resolved ultrafast mid-infrared transient reflection spectroscopy measurements are performed to study the dynamical anisotropic optical properties of BP under magnetic fields up to 9 T. The relaxation dynamics of photoexcited carrier is found to be insensitive to the applied magnetic field due to the broadening of the Landau levels and large effective mass of carriers. While the anisotropic optical response of BP decreases with increasing magnetic field, its enhancement due to the excitation of hot carriers is similar to that without magnetic field. These experimental results can be well interpreted by the magneto-optical conductivity of the Landau levels of BP thin film, based on an effective k · p Hamiltonian and linear response theory. These findings suggest attractive possibilities of multi-dimensional control of anisotropic response (AR) of BP with light, electric and magnetic field, which further introduces BP to the fantastic magnetic field sensitive applications.

  5. Reduced mycorrhizal responsiveness leads to increased competitive tolerance in an invasive exotic plant

    Science.gov (United States)

    Lauren P. Waller; Ragan M. Callaway; John N. Klironomos; Yvette K. Ortega; John L. Maron

    2016-01-01

    1. Arbuscular mycorrhizal (AM) fungi can exert a powerful influence on the outcome of plant–plant competition. Since some exotic plants interact differently with soil biota such as AM fungi in their new range, range-based shifts in AM responsiveness could shift competitive interactions between exotic and resident plants, although this remains poorly studied. 2. We...

  6. Priming, induction and modulation of plant defence responses by bacterial lipopolysaccharides

    DEFF Research Database (Denmark)

    Newman, Mari-Anne; Dow, J. Maxwell; Molinaro, Antonio

    2007-01-01

    to the triggering of defence responses or to the priming of the plant to respond more rapidly and/or to a greater degree to subsequent pathogen challenge. LPS from symbiotic bacteria can have quite different effects on plants to those of pathogens. Some details are emerging of the structures within LPS......Bacterial lipopolysaccharides (LPSs) have multiple roles in plant-microbe interactions. LPS contributes to the low permeability of the outer membrane, which acts as a barrier to protect bacteria from plant-derived antimicrobial substances. Conversely, perception of LPS by plant cells can lead...... that are responsible for induction of these different plant responses. The lipid A moiety is not solely responsible for all of the effects of LPS in plants; core oligosaccharide and O-antigen components can elicit specific responses. Here, we review the effects of LPS in induction of defence-related responses...

  7. Leaf antioxidant fluctuations and growth responses in saplings of Caesalpinia echinata Lam. (brazilwood) under an urban stressing environment.

    Science.gov (United States)

    Bulbovas, Patricia; de Moraes, Regina Maria; Spasiani Rinaldi, Mirian Cilene; Luiza Cunha, Adriana; Carvalho Delitti, Welington Braz; Domingos, Marisa

    2010-05-01

    We intended to establish how efficient the leaf antioxidant responses of C. echinata are against oxidative environmental conditions observed in an urban environment and their relations to growth and biomass parameters. Plants were grown for 15 months in four sites: Congonhas and Pinheiros, affected by pollutants from vehicular emissions; Ibirapuera, affected by high O(3) concentrations; and a greenhouse with filtered air. Fifteen plants were quarterly removed from each site for analysis of antioxidants, growth and biomass. Plants growing in polluted sites showed alterations in their antioxidants. They were shorter, had thicker stems and produced less leaf biomass than plants maintained under filtered air. The fluctuations in the levels of antioxidants were significantly influenced by combined effects of climatic and pollution variables. The higher were the antioxidant responses and the concentrations of pollutant markers of air contamination in each site the slower were the growth and biomass production. Copyright 2009 Elsevier Inc. All rights reserved.

  8. Soil ecosystem functioning under climate change: plant species and community effects.

    Science.gov (United States)

    Kardol, Paul; Cregger, Melissa A; Campany, Courtney E; Classen, Aimee T

    2010-03-01

    Feedbacks of terrestrial ecosystems to atmospheric and climate change depend on soil ecosystem dynamics. Soil ecosystems can directly and indirectly respond to climate change. For example, warming directly alters microbial communities by increasing their activity. Climate change may also alter plant community composition, thus indirectly altering the soil communities that depend on their inputs. To better understand how climate change may directly and indirectly alter soil ecosystem functioning, we investigated old-field plant community and soil ecosystem responses to single and combined effects of elevated [CO2], warming, and precipitation in Tennessee (USA). Specifically, we collected soils at the plot level (plant community soils) and beneath dominant plant species (plant-specific soils). We used microbial enzyme activities and soil nematodes as indicators for soil ecosystem functioning. Our study resulted in two main findings: (1) Overall, while there were some interactions, water, relative to increases in [CO2] and warming, had the largest impact on plant community composition, soil enzyme activity, and soil nematodes. Multiple climate-change factors can interact to shape ecosystems, but in our study, those interactions were largely driven by changes in water. (2) Indirect effects of climate change, via changes in plant communities, had a significant impact on soil ecosystem functioning, and this impact was not obvious when looking at plant community soils. Climate-change effects on enzyme activities and soil nematode abundance and community structure strongly differed between plant community soils and plant-specific soils, but also within plant-specific soils. These results indicate that accurate assessments of climate-change impacts on soil ecosystem functioning require incorporating the concurrent changes in plant function and plant community composition. Climate-change-induced shifts in plant community composition will likely modify or counteract the

  9. Technical data for concentrated solar power plants in operation, under construction and in project

    Directory of Open Access Journals (Sweden)

    Ugo Pelay

    2017-08-01

    Full Text Available This article presents technical data for concentrated solar power (CSP plants in operation, under construction and in project all over the world in the form of tables. These tables provide information about plants (e.g., name of the CSP plant, country of construction, owner of the plant, aim of the plant and their technical characteristics (e.g., CSP technology, solar power, area of the plant, presence and type of hybridization system, electricity cost, presence and type of TES, power cycle fluid, heat transfer fluid, operating temperature, operating pressure, type of turbine, type and duration of storage, etc.. Further interpretation of the data and discussions on the current state-of-the-art and future trends of CSP can be found in the associated research article (Pelay et al., 2017 [1].

  10. Effect of l-tryptophan on plant weight and pod weight in chickpea under rainfed conditions

    International Nuclear Information System (INIS)

    Abbas, S.H.; Sohail, M.

    2013-01-01

    Exogenous application of plant growth regulators is an important element in modern day agricultural production technology. The precursor of auxin, L-Tryptophan (L-TRP), is the most important plant growth regulator and is physiologically very vital in modelling plant growth and development. To evaluate the effect of L-TRP on chickpea plant weight and pod weight, a field experiment was conducted during 2003, employing randomised complete block design under rain-fed conditions. The treatments were L-TRP at the rate 10 -2 M, L-TRP at the rate 10-3 M, L-TRP at the rate 10/sup -4/ M and a control. Analysis showed that L-TRP at the rate 10/sup -3/M had a significant effect on plant and pod weight, suggesting the additional effect of plant growth promoting factor provided by auxin production. The L-TRP improved the crop vegetative and reproductive growth that consequently increases pod weight. (author)

  11. Acclimation of a terrestrial plant to submergence facilitates gas exchange under water

    DEFF Research Database (Denmark)

    Mommer, L.; Pedersen, O.; Visser, E. J. W.

    2004-01-01

    Flooding imposes stress upon terrestrial plants since it severely hampers gas exchange rates between the shoot and the environment. The resulting oxygen deficiency is considered to be the major problem for submerged plants. Oxygen microelectrode studies have, however, shown that aquatic plants...... of this terrestrial plant species to submergence for gas exchange capacity is also shown. Shoot acclimation to submergence involved a reduction of the diffusion resistance to gases, which was not only functional by increasing diffusion of oxygen into the plant, but also by increasing influx of CO2, which enhances...... maintain relatively high internal oxygen pressures under water, and even may release oxygen via the roots into the sediment, also in dark. Based on these results, we challenge the dogma that oxygen pressures in submerged terrestrial plants immediately drop to levels at which aerobic respiration is impaired...

  12. Technical data for concentrated solar power plants in operation, under construction and in project.

    Science.gov (United States)

    Pelay, Ugo; Luo, Lingai; Fan, Yilin; Stitou, Driss; Rood, Mark

    2017-08-01

    This article presents technical data for concentrated solar power (CSP) plants in operation, under construction and in project all over the world in the form of tables. These tables provide information about plants (e.g., name of the CSP plant, country of construction, owner of the plant, aim of the plant) and their technical characteristics (e.g., CSP technology, solar power, area of the plant, presence and type of hybridization system, electricity cost, presence and type of TES, power cycle fluid, heat transfer fluid, operating temperature, operating pressure, type of turbine, type and duration of storage, etc.). Further interpretation of the data and discussions on the current state-of-the-art and future trends of CSP can be found in the associated research article (Pelay et al., 2017) [1].

  13. Differential sulphur assimilation mechanism regulates response of Arabidopsis thaliana natural variation towards arsenic stress under limiting sulphur condition.

    Science.gov (United States)

    Khare, Ria; Kumar, Smita; Shukla, Tapsi; Ranjan, Avriti; Trivedi, Prabodh Kumar

    2017-09-05

    Arsenic (As) is a ubiquitous element, which imposes threat to crops productivity and human health through contaminated food chain. As a part of detoxification mechanism, As is chelated and sequestered into the vacuoles via sulphur containing compounds glutathione (GSH) and phytochelatins (PCs). Under limiting sulphur (LS) conditions, exposure of As leads to enhanced toxic effects in plants. Therefore, it is a prerequisite to understand molecular mechanisms involved in As stress response under sulphur deficiency conditions in plants. In recent years, natural variation has been utilized to explore the genetic determinants linked to plant development and stress response. In this study, natural variation in Arabidopsis has been utilized to understand the molecular mechanisms underlying LS and As(III) stress response. Analysis of different accession of Arabidopsis led to the identification of Koz2-2 and Ri-0 as the most tolerant and sensitive accessions, respectively, towards As(III) and LS+As(III) stress. Biochemical analysis and expression profiling of the genes responsible for sulphur transport and assimilation as well as metal detoxification and accumulation revealed significantly enhanced sulphur assimilation mechanism in Koz2-2 as compared to Ri-0. Analyses suggest that genetic variation regulates differential response of accessions towards As(III) under LS condition. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Gravimetric phenotyping of whole plant transpiration responses to atmospheric vapour pressure deficit identifies genotypic variation in water use efficiency.

    Science.gov (United States)

    Ryan, Annette C; Dodd, Ian C; Rothwell, Shane A; Jones, Ros; Tardieu, Francois; Draye, Xavier; Davies, William J

    2016-10-01

    There is increasing interest in rapidly identifying genotypes with improved water use efficiency, exemplified by the development of whole plant phenotyping platforms that automatically measure plant growth and water use. Transpirational responses to atmospheric vapour pressure deficit (VPD) and whole plant water use efficiency (WUE, defined as the accumulation of above ground biomass per unit of water used) were measured in 100 maize (Zea mays L.) genotypes. Using a glasshouse based phenotyping platform with naturally varying VPD (1.5-3.8kPa), a 2-fold variation in WUE was identified in well-watered plants. Regression analysis of transpiration versus VPD under these conditions, and subsequent whole plant gas exchange at imposed VPDs (0.8-3.4kPa) showed identical responses in specific genotypes. Genotype response of transpiration versus VPD fell into two categories: 1) a linear increase in transpiration rate with VPD with low (high WUE) or high (low WUE) transpiration rate at all VPDs, 2) a non-linear response with a pronounced change point at low VPD (high WUE) or high VPD (low WUE). In the latter group, high WUE genotypes required a significantly lower VPD before transpiration was restricted, and had a significantly lower rate of transpiration in response to VPD after this point, when compared to low WUE genotypes. Change point values were significantly positively correlated with stomatal sensitivity to VPD. A change point in stomatal response to VPD may explain why some genotypes show contradictory WUE rankings according to whether they are measured under glasshouse or field conditions. Furthermore, this novel use of a high throughput phenotyping platform successfully reproduced the gas exchange responses of individuals measured in whole plant chambers, accelerating the identification of plants with high WUE. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  15. Ethylenediurea as a potential tool in evaluating ozone phytotoxicity: a review study on physiological, biochemical and morphological responses of plants.

    Science.gov (United States)

    Tiwari, Supriya

    2017-06-01

    Present-day climate change scenario has intensified the problem of continuously increasing ground-level ozone (O 3 ), which is responsible for causing deleterious effects on growth and development of plants. Studies involving use of ethylenediurea (EDU), a chemical with antiozonant properties, have given some promising results in evaluating O 3 injury in plants. The use of EDU is especially advantageous in developing countries which face a more severe problem of ground-level O 3 , and technical O 3 -induced yield loss assessment techniques like open-top chambers cannot be used. Recent studies have detected a hormetic response of EDU on plants; i.e. treatment with higher EDU concentrations may or may not show any adverse effect on plants depending upon the experimental conditions. Although the mode of action of EDU is still debated, it is confirmed that EDU remains confined in the apoplastic regions. Certain studies indicate that EDU significantly affects the electron transport chain and has positive impact on the antioxidant defence machinery of the plants. However, the mechanism of protecting the yield of plants without significantly affecting photosynthesis is still questionable. This review discusses in details the probable mode of action of EDU on the basis of available data along with the impact of EDU on physiological, biochemical, growth and yield response of plants under O 3 stress. Data regarding the effect of EDU on plant 'omics' is highly insufficient and can form an important aspect of future EDU research.

  16. Excessive Response-Repetition Costs under Task Switching: How Response Inhibition Amplifies Response Conflict

    Science.gov (United States)

    Grzyb, Kai Robin; Hubner, Ronald

    2013-01-01

    The size of response-repetition (RR) costs, which are usually observed on task-switch trials, strongly varies between conditions with univalent and bivalent stimuli. To test whether top-down or bottom-up processes can account for this effect, we assessed in Experiment 1 baselines for univalent and bivalent stimulus conditions (i.e., for stimuli…

  17. Plastic responses of native plant root systems to the presence of an invasive annual grass.

    Science.gov (United States)

    Phillips, Allison J; Leger, Elizabeth A

    2015-01-01

    • The ability to respond to environmental change via phenotypic plasticity may be important for plants experiencing disturbances such as climate change and plant invasion. Responding to belowground competition through root plasticity may allow native plants to persist in highly invaded systems such as the cold deserts of the Intermountain West, USA.• We investigated whether Poa secunda, a native bunchgrass, could alter root morphology in response to nutrient availability and the presence of a competitive annual grass. Seeds from 20 families were grown with high and low nutrients and harvested after 50 d, and seeds from 48 families, grown with and without Bromus tectorum, were harvested after ∼2 or 6 mo. We measured total biomass, root mass fraction, specific root length (SRL), root tips, allocation to roots of varying diameter, and plasticity in allocation.• Plants had many parallel responses to low nutrients and competition, including increased root tip production, a trait associated with tolerance to reduced resources, though families differed in almost every trait and correlations among trait changes varied among experiments, indicating flexibility in plant responses. Seedlings actively increased SRL and fine root allocation under competition, while older seedlings also increased coarse root allocation, a trait associated with increased tolerance, and increased root mass fraction.• The high degree of genetic variation for root plasticity within natural populations could aid in the long-term persistence of P. secunda because phenotypic plasticity may allow native species to persist in invaded and fluctuating resource environments. © 2015 Botanical Society of America, Inc.

  18. AN ETHNOBOTANICAL STUDY OF MEDICINAL PLANTS USED IN VILLAGES UNDER JONGILANGA TRIBAL COUNCIL, MPUMALANGA, SOUTH AFRICA.

    Science.gov (United States)

    Tshikalange, Thilivhali Emmanuel; Mophuting, Boikanyo Calvin; Mahore, James; Winterboer, Stefan; Lall, Namrita

    2016-01-01

    Medicinal plants remain an integral part of the lives of people in rural areas. The aim of this study was to document information about the medicinal plants used by Shangaan people in villages under Jongilanga tribal council, Bushbuckridge municipality, Mpumalanga Province, South Africa. An ethnobotanical survey of medicinal plants was conducted using a semi-structured questionnaire with 15 traditional healers as informants; one of them also served as a field guide during data collection. Results were analysed by using various quantitative indices of information consensus factor (ICF), use report (UR), frequency citation (FC) and relative frequency citation (RFC). The study reported 86 medicinal plants used in villages for the treatment of various ailments, the majority (25 species) of which were used for urino-genital disorders. The Fabaceae family was the most represented family (17 species) of all the medicinal plants recorded in this study. The roots were the most frequently used plant part, accounting for 56% of the plants reported, and decoctions were often used in the preparation of herbal remedies. Respiratory diseases had the highest ICF value recorded among the 8 categories of ailments. The highest use report was reported for Combretum collinum (4), while the FC and RFC values (15) were highest in 12 plant species. The study revealed that medicinal plants are still widely used in rural areas and this documentation can serve as an ethno pharmacological basis for selecting plants with potential pharmaceutical properties.

  19. Delaying onion planting to control onion maggot (Diptera: Anthomyiidae): efficacy and underlying mechanisms.

    Science.gov (United States)

    Nault, Brian A; Werling, Benjamin P; Straub, Richard W; Nyrop, Jan P

    2011-10-01

    Onion maggot, Delia antiqua (Meigen) (Diptera: Anthomyiidae), is an important pest of onion, Allium cepa L., in northern temperate areas, especially in the Great Lakes region of North America Management of D. antiqua relies on insecticide use at planting, but insecticide resistance can cause control failures that threaten the long-term viability of this strategy. Delaying the time onions are planted was investigated as an alternative management approach for D. antiqua and the ecological and behavioral mechanisms underlying host age and insect relationships were examined in laboratory and field experiments. Delaying onion planting by two to four weeks reduced damage to onions by 35 and 90%, respectively. Onions planted later emerged later and this reduced the period overwintered flies had to oviposit on the plants. Moreover, flies tended to lay few to no eggs on these young, late-planted onions. As anticipated, D. antiqua laid 4-8 times more eggs on older onions than on young onions, and older onions were more resilient to injury caused by D. antiqua neonates compared with younger onions. However, the resiliency to maggot attack lessened as the density of D. antiqua increased from 2 to 10 eggs per plant, which probably explains why greater levels of maggot damage are typically observed in early onion plantings compared with later plantings. Delaying onion planting until mid-May reduced D. antiqua damage without jeopardizing the period required to produce marketable yield, but this cultural tactic must be combined with other management strategies to prevent economic loss.

  20. Does triacylglycerol (TAG) serve a photoprotective function in plant leaves? An examination of leaf lipids under shading and drought.

    Science.gov (United States)

    Marchin, Renée M; Turnbull, Tarryn L; Deheinzelin, Audrey I; Adams, Mark A

    2017-11-01

    Plant survival in many ecosystems requires tolerance of large radiation loads, unreliable water supply and suboptimal soil fertility. We hypothesized that increased production of neutral lipids (triacylglycerols, TAGs) in plant leaves is a mechanism for dissipating excess radiation energy. In a greenhouse experiment, we combined drought and shade treatments and examined responses among four species differing in life form, habitat, and drought- and shade-tolerance. We also present a lipid extraction protocol suitable for sclerophyllous leaves of native Australian trees (e.g. Acacia, Eucalyptus). Fluorescence measurements indicated that plants exposed to full sunlight experienced mild photoinhibition during our experiment. Accumulation of TAGs did not follow photosynthetic capacity, but instead, TAG concentration increased with non-photochemical quenching. This suggests that plants under oxidative stress may increase biosynthesis of TAGs. Moderate drought stress resulted in a 60% reduction in TAG concentration in wheat (Triticum aestivum). Shading had no effect on TAGs, but increased concentrations of polar lipids in leaves; for example, acclimation to shade in Austrodanthonia spp., a native Australian grass, resulted in a 60% increase in associated polar lipids and higher foliar chlorophyll concentrations. Shading also reduced the digalactosyldiacylglycerol:monogalactosyldiacylglycerol (DGDG:MGDG) ratio in leaves, with a corresponding increase in the degree of unsaturation and thus fluidity of thylakoid membranes of chloroplasts. Our results suggest that prevention of photodamage may be coordinated with accumulation of TAGs, although further research is required to determine if TAGs serve a photoprotective function in plant leaves. © 2017 Scandinavian Plant Physiology Society.

  1. An improved, low-cost, hydroponic system for growing Arabidopsis and other plant species under aseptic conditions.

    Science.gov (United States)

    Alatorre-Cobos, Fulgencio; Calderón-Vázquez, Carlos; Ibarra-Laclette, Enrique; Yong-Villalobos, Lenin; Pérez-Torres, Claudia-Anahí; Oropeza-Aburto, Araceli; Méndez-Bravo, Alfonso; González-Morales, Sandra-Isabel; Gutiérrez-Alanís, Dolores; Chacón-López, Alejandra; Peña-Ocaña, Betsy-Anaid; Herrera-Estrella, Luis

    2014-03-21

    Hydroponics is a plant growth system that provides a more precise control of growth media composition. Several hydroponic systems have been reported for Arabidopsis and other model plants. The ease of system set up, cost of the growth system and flexibility to characterize and harvest plant material are features continually improved in new hydroponic system reported. We developed a hydroponic culture system for Arabidopsis and other model plants. This low cost, proficient, and novel system is based on recyclable and sterilizable plastic containers, which are readily available from local suppliers. Our system allows a large-scale manipulation of seedlings. It adapts to different growing treatments and has an extended growth window until adult plants are established. The novel seed-holder also facilitates the transfer and harvest of seedlings. Here we report the use of our hydroponic system to analyze transcriptomic responses of Arabidopsis to nutriment availability and plant/pathogen interactions. The efficiency and functionality of our proposed hydroponic system is demonstrated in nutrient deficiency and pathogenesis experiments. Hydroponically grown Arabidopsis seedlings under long-time inorganic phosphate (Pi) deficiency showed typical changes in root architecture and high expression of marker genes involved in signaling and Pi recycling. Genome-wide transcriptional analysis of gene expression of Arabidopsis roots depleted of Pi by short time periods indicates that genes related to general stress are up-regulated before those specific to Pi signaling and metabolism. Our hydroponic system also proved useful for conducting pathogenesis essays, revealing early transcriptional activation of pathogenesis-related genes.

  2. Response of tomato cultivars to different organic fertilizers under agro-climatic conditions of mingora, Swat

    International Nuclear Information System (INIS)

    Yousafzai, S.K.; Khan, S.M.; Khan, J.; Khan, S.A.; Hussain, I.; Naz, I.

    2016-01-01

    An experiment was conducted at Agricultural Research Institute (ARI) Mingora, Swat during 2013 to study the effect of different organic fertilizers of tomato cultivars under the agro-climatic conditions of Mingora, Swat. The experiment was conducted in randomized complete block design with split plot arrangements having four treatments with three replications. Almost all the traits showed significant differences for organic fertilizers and varieties, while their interactions had a varied response. The analyzed data showed that poultry manure gave maximum yield (24.65 t ha/sup -1/), followed by FYM (24.38 t ha/sup -1/) and mushroom compost (24.11 t ha/sup -1/ ) while minimum was recorded in plots where no organic fertilizer was used. The results revealed that cultivar, Rio Grand showed maximum number of plant survival percentage (98.33 percent), days to flowering (40.73), number of flowers plant/sup -1/ (6.23), number of fruit plant (25.67), fruit 3 weight (8.84 kg), number of leaves plant/sup -1/ (83.66), fruit size (64.70 cm/sup 3/) and total yield (25.67 t ha/sup -1/ ) in Farm Yard Manure (FYM). Considering the overall performance, it was found that the tomato cultivar Rio Grand was promising for yield and other characters where FYM was applied. (author)

  3. Vetiver (Vetiveria zizanioides) responses to fertilization and salinity under irrigation conditions.

    Science.gov (United States)

    Edelstein, Menahem; Plaut, Zvi; Dudai, Nativ; Ben-Hur, Meni

    2009-10-01

    Vetiver (Vetiveria zizanioides) has not been widely introduced in arid and semi-arid regions where irrigation, fertilization, and salinity are important factors in plant growth. The main objective of this study was to determine the response of vetiver to fertilization (fertigation) and salinity and their interactions under irrigated conditions. The experiment was conducted in a greenhouse in 10-L pots. Combined effects of three nutrients concentrations and three salinity levels of electrical conductivity (EC) 1, 3 and 6 dS/m in the irrigation water on growth and transpiration of vetiver plants and the content of different elements in their foliage were studied. Similar contents of approximately 3.7 g/kg Na, approximately 5.77 g/kg Ca and approximately 2.55 g/kg Mg were found in the foliage of all the plants irrigated with the different fertilizer and salinity levels. Concentrations of 59 mg/L N and 36.1mg/L K in the irrigation water were sufficient for vetiver plants needs at the different salinity levels tested. The salinity threshold (the maximum EC in the soil solution that does not cause a significant yield reduction) for vetiver was between 3 and 6 dS/m. A concentration of 15.2mg/L P in the irrigation water was the optimum value for vetiver growth in the three salinity levels, resulting in an average content of 5.95 g/kg P in plant foliage. It is suggested that vetiver is sensitive to excess P (>8.66 g/kg). Increasing EC in the irrigation water to 6 dS/m decreased plant foliage biomass mainly due to an increase in the osmotic potential of the irrigation water and high Cl(-) concentration in the foliage.

  4. Response of cylindrical steel shell under seismic loading

    International Nuclear Information System (INIS)

    Tariq, M.; Amin, K.M.

    2003-01-01

    The seismic response of a cylindrical shell is simulated using the finite element method, and by spectral analysis. For this purpose the fundamental frequency of the cylinder is first calculated and compared with a published result. The mode shapes are also calculated which are later used for spectral analysis. The boundary nodes of the shell are displaced periodically according to a predetermined function of time by employing the acceleration time history of the El Centro earthquake to simulate the seismic loading. However, to conduct spectral analysis, the displacements are first transformed from the time domain to frequency domain using the Fast Fourier transformation. This spectral data is then used to obtain the actual displacement in the first mode under the given seismic loading. The techniques employed here can be used for cylindrical shell structures like rotor of a gas centrifuge, besides other structures that are subjected to seismic loading, besides in other time dependent loading conditions, for example rocket motor vibrations. (author)

  5. Nonlinear mechanical response of supercooled melts under applied forces

    Science.gov (United States)

    Cárdenas, Heliana; Frahsa, Fabian; Fritschi, Sebastian; Nicolas, Alexandre; Papenkort, Simon; Voigtmann, Thomas; Fuchs, Matthias

    2017-08-01

    We review recent progress on a microscopic theoretical approach to describe the nonlinear response of glass-forming colloidal dispersions under strong external forcing leading to homogeneous and inhomogeneous flow. Using mode-coupling theory (MCT), constitutive equations for the rheology of viscoelastic shear-thinning fluids are obtained. These are, in suitably simplified form, employed in continuum fluid dynamics, solved by a hybrid-Lattice Boltzmann (LB) algorithm that was developed to deal with long-lasting memory effects. The combined microscopic theoretical and mesoscopic numerical approach captures a number of phenomena far from equilibrium, including the yielding of metastable states, process-dependent mechanical properties, and inhomogeneous pressure-driven channel flow.

  6. Alpine plant functional group responses to fertiliser addition depend on abiotic regime and community composition.

    NARCIS (Netherlands)

    Onipchenko, V.G.; Makarov, M.I.; Akmetzhanova, A.A.; Soudzilovskaia, N.A.; Aibazova, F.U.; Elkanova, M.K.; Stogova, A.V.; Cornelissen, J.H.C.

    2012-01-01

    Background and aims: We ask how productivity responses of alpine plant communities to increased nutrient availability can be predicted from abiotic regime and initial functional type composition. Methods: We compared four Caucasian alpine plant communities (lichen heath, Festuca varia grassland,

  7. Interacting TCP and NLP transcription factors control plant responses to nitrate availability.

    Science.gov (United States)

    Guan, Peizhu; Ripoll, Juan-José; Wang, Renhou; Vuong, Lam; Bailey-Steinitz, Lindsay J; Ye, Dening; Crawford, Nigel M

    2017-02-28

    Plants have evolved adaptive strategies that involve transcriptional networks to cope with and survive environmental challenges. Key transcriptional regulators that mediate responses to environmental fluctuations in nitrate have been identified; however, little is known about how these regulators interact to orchestrate nitrogen (N) responses and cell-cycle regulation. Here we report that teosinte branched1/cycloidea/proliferating cell factor1-20 (TCP20) and NIN-like protein (NLP) transcription factors NLP6 and NLP7, which act as activators of nitrate assimilatory genes, bind to adjacent sites in the upstream promoter region of the nitrate reductase gene, NIA1 , and physically interact under continuous nitrate and N-starvation conditions. Regions of these proteins necessary for these interactions were found to include the type I/II Phox and Bem1p (PB1) domains of NLP6&7, a protein-interaction module conserved in animals for nutrient signaling, and the histidine- and glutamine-rich domain of TCP20, which is conserved across plant species. Under N starvation, TCP20-NLP6&7 heterodimers accumulate in the nucleus, and this coincides with TCP20 and NLP6&7-dependent up-regulation of nitrate assimilation and signaling genes and down-regulation of the G 2 /M cell-cycle marker gene, CYCB1;1 TCP20 and NLP6&7 also support root meristem growth under N starvation. These findings provide insights into how plants coordinate responses to nitrate availability, linking nitrate assimilation and signaling with cell-cycle progression.

  8. Mineral nutrition and plant responses to elevated levels of atmospheric CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Ahluwalia, A.

    1996-08-01

    The atmospheric concentration of CO{sub 2}, a radiatively-active ({open_quotes}green-house{close_quotes}) gas, is increasing. This increase is considered a post-industrial phenomenon attributable to increasing rates of fossil fuel combustion and changing land use practices, particularly deforestation. Climate changes resulting from such elevated atmospheric CO{sub 2} levels, in addition to the direct effects of increased CO{sub 2}, are expected to modify the productivity of forests and alter species distributions. Elevated levels of CO{sub 2} have been shown, in some cases, to lead to enhanced growth rates in plants, particularly those with C{sub 3} metabolism - indicating that plant growth is CO{sub 2}-limited in these situations. Since the major process underlying growth is CO{sub 2} assimilation via photosynthesis in leaves, plant growth represents a potential for sequestering atmospheric carbon into biomass, but this potential could be hampered by plant carbon sink size. Carbon sinks are utilization sites for assimilated carbon, enabling carbon assimilation to proceed without potential inhibition from the accumulation of assimilate (photosynthate). Plant growth provides new sinks for assimilated carbon which permits greater uptake of atmospheric carbon dioxide. However, sinks are, on the whole, reduced in size by stress events due to the adverse effects of stress on photosynthetic rates and therefore growth. This document reviews some of the literature on plant responses to increasing levels of atmospheric carbon dioxide and to inadequate nutrient supply rates, and with this background, the potential for nutrient-limited plants to respond to increasing carbon dioxide is addressed. Conclusions from the literature review are then tested experimentally by means of a case study exploring carbon-nitrogen interactions in seedlings of loblolly pine.

  9. On seismic response characteristics of floating nuclear plant barge, (2)

    International Nuclear Information System (INIS)

    Hagiwara, Yutaka; Masuko, Yosio; Kurihara, Chizuko; Sasaki, Shunji; Sakurai, Akio

    1987-01-01

    Though floating nuclear plants (FNPs) is effectively isolated from horizontal earthquake motion, vertical earthquake motion on FNPs is almost the same as the ground motion inevitably. Therefore an alternative design concept of FNPs has been developed, which is isolated from vertical earthquake motion as well, utilizing pneumatic chambers equipped to the bottom of the barge. In this report, a simple analytical solution, which describes the vertical earthquake response of a floating body which has pneumatic chambers below its bottom, is derived. And a shaking table test and an earthquake response observation of floating bodies with pneumatic chambers are conducted to verify the solution. The prediction by the analytical solution gives sufficient agreement with the experimental results, so that the solution is confirmed to be valid. Then the fundamental geometry of a FNP barge with pneumatic chambers is assumed, and finally, it is evaluated by the solution that high-frequency ( ≥ 1 Hz) vertical acceleration on the barge induced by vertical component of earthquakes, will be reduced to approximately, a quater of the ground motion. (author)

  10. GENETIC VARIABILITY OF CULTURED PLANT TISSUES UNDER NORMAL CONDITIONS AND UNDER STRESS

    Directory of Open Access Journals (Sweden)

    Dolgikh Yu.I.

    2012-08-01

    Full Text Available The genetic variability induced by in vitro conditions known as somaclonal variation is of practical interest due to its potential uses in plant breeding but, on the other hand, if clonal propagation or transformation is main goal, it becomes an unwelcome phenomenon. Thus, it is important to know frequency, the genomic distribution, the mechanisms and factors influencing somaclonal variation. We studied variability of PCR-based DNA markers of cultured tissues and regenerated plants of maize and bread wheat. The original A188 line of maize and the somaclones obtained were tested using 38 RAPD and 10 ISSR primers. None of the A188 plants showed variation in the RAPD and ISSR spectra for any of the primers used. However, the PCR spectra obtained from the somaclones demonstrated some variations, i.e., 22 RAPD primers and 6 ISSR primers differentiated at least one somaclonal variant from the progenitor line. Six SCAR markers were developed based on several RAPD and ISSR fragments. The inheritance of these SCAR markers was verified in the selfing progeny of each somaclone in the R1–R4 generations and in the hybrids, with A188 as the parental line in the F1 and F2 generations. These markers were sequenced and bioinformatic searches were performed to understand the molecular events that may underlie the variability observed in the somaclones. All changes were found in noncoding sequences and were induced by different molecular events, such as the insertion of long terminal repeat transposon, precise miniature inverted repeat transposable element (MITE excision, microdeletion, recombination, and a change in the pool of mitochondrial DNA. In two groups of independently produced somaclones, the same features (morphological, molecular were variable, which confirms the theory of ‘hot spots’ occurring in the genome. The presence of the same molecular markers in the somaclones and in different non-somaclonal maize variants suggests that in some cases

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

    Science.gov (United States)

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

    2014-01-01

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

  12. Belowground Water Dynamics Under Contrasting Annual and Perennial Plant Communities in an Agriculturally-Dominated Landscape

    Science.gov (United States)

    Mora, G.; Asbjornsen, H.; Helmers, M. J.; Shepherd, G. W.

    2005-12-01

    The conversion from grasslands and forests to row-crops in the Midwest has affected soil water cycling because plant characteristics are one of the main parameters determining soil storage capacity, infiltration rates, and surface runoff. Little is known, however, about the extent of modification of soil water dynamics under different plant communities. To address this important issue, we are documenting soil water dynamics under contrasting perennial and annual plant communities in an agriculturally-dominated landscape. Measurements of soil moisture and depths of uptake of source water were obtained for six vegetative cover types (corn and soybean field, brome pasture, degraded savanna, restored savanna, and restored prairie) at the Neal Smith National Wildlife Refuge in Prairie City, Iowa. The depths of uptake of soil water were determined on the basis of oxygen isotope composition of soil water and stem water. Measurements were performed once a month during an entire growing season. Preliminary results indicate that soil water present under the different vegetation types show similar profiles with depth during the dry months. Soil water in the upper 5 cm is enriched in oxygen-18 by about 5 per mil relative to soil water at 100 cm. Our preliminary results also indicate that the isotopic composition of stem water from annual plants is typically higher by about 2 per mil relative to that of stem water from perennial plants during the dry period. Whereas the oxygen isotopic composition for corn stem water is -5.49 per mil, that for elm and oak stem water is -7.62 and -7.51 per mil, respectively. The higher isotope values for corn suggest that annual crop plants are withdrawing water from shallower soil horizons relative to perennial plants. Moreover, our preliminary data suggest lower moisture content in soil under annual plant cover. We propose that the presence of deeper roots in the perennial vegetation allows these plants to tap into deeper water sources when

  13. Plant and microbial responses to nitrogen and phosphorus addition across an elevational gradient in subarctic tundra.

    Science.gov (United States)

    Sundqvist, Maja K; Liu, Zhanfeng; Giesler, Reiner; Wardle, David A

    2014-07-01

    Temperature and nutrients are major limiting factors in subarctic tundra. Experimental manipulation of nutrient availability along elevational gradients (and thus temperature) can improve our understanding of ecological responses to climate change. However, no study to date has explored impacts of nutrient addition along a tundra elevational gradient, or across contrasting vegetation types along any elevational gradient. We set up a full factorial nitrogen (N) and phosphorus (P) fertilization experiment in each of two vegetation types (heath and meadow) at 500 m, 800 m, and 1000 m elevation in northern Swedish tundra. We predicted that plant and microbial communities in heath or at lower elevations would be more responsive to N addition while communities in meadow or at higher elevations would be more responsive to P addition, and that fertilizer effects would vary more with elevation for the heath than for the meadow. Although our results provided little support for these predictions, the relationship between nutrient limitation and elevation differed between vegetation types. Most plant and microbial properties were responsive to N and/or P fertilization, but responses often varied with elevation and/or vegetation type. For instance, vegetation density significantly increased with N + P fertilization relative to the other fertilizer treatments, and this increase was greatest at the lowest elevation for the heath but at the highest elevation for the meadow. Arbuscular mycorrhizae decreased with P fertilization at 500 m for the meadow, but with all fertilizer treatments in both vegetation types at 800 m. Fungal to bacterial ratios were enhanced by N+ P fertilization for the two highest elevations in the meadow only. Additionally, microbial responses to fertilization were primarily direct rather than indirect via plant responses, pointing to a decoupled response of plant and microbial communities to nutrient addition and elevation. Because our study shows how two

  14. Proposal of a Simple Plant Growth System under Microgravity Conditions in Space

    Science.gov (United States)

    Hirai, Hiroaki; Kitaya, Yoshiaki; Hirai, Takehiro; Tsukamoto, Koya; Yamashita, Youichirou

    2012-07-01

    Plant culture in space has multiple functions for human life support such as providing food and purifying air and water. It is also suggested that crew can relieve their stress by watching growing plants and by enjoying fresh vegetable food during staying for several months in the International Space Station. Under such circumstances, it is an utmost importance to develop plant culture equipment that can be handled more easily by crew. This study aims to develop an easy-to-use plant growth system with modification of commercial household plant culture equipment. The item is equipped with a peltier device for cooling air and collecting water vapor in the growth room. The study was conducted to examine the performance of the equipment under microgravity conditions that were created by the parabolic airplane flights. As a result, the temperature of the peltier device was affected under the microgravity conditions due to the absence of heat convection. When an air flow was made with an air circulation fan, the temperature of the peltier device was stable to gravity changes. The water recycling method for an automatic nutrient solution supply system in the closed plant culture equipment under microgravity is proposed. In addition, a high output white LEDs showing a good performance for growing leafy vegetables will be introduced.

  15. [Effect of AM fungi on water and nutrition status of corn plants under salt stress].

    Science.gov (United States)

    Feng, G; Li, X; Zhang, F; Li, S

    2000-08-01

    Under NaCl stress, the dry matter production of corn plants inoculated with or without arbuscular mycorrhizal (AM) fungus (Glomus mosseae) was decreased, but the decrement for non-mycorrhizal plants was 10% higher than that for mycorrhizal ones. Under salt stress condition, the dry weights of root system and aboveground part of mycorrhizal corn and its leaf water potential were higher than those of non-mycorrhizal corn, while the proline content of mycorrhizal corn was less than that of non-mycorrhizal corn. The contribution of hypha to P uptake of plants decreased from 45.3% to 42.6%, while the effect of AM fungi on plant growth increased from 30.9% to 63.5% under salt stress condition. The above-mentioned results indicated that the mechanism that AM fungi enhance the salt-resistance of corn is related with the improvements of water and P nutrition conditions. Meanwhile, it was found whether under salt stress or not, the ratio of P accumulation of root system to aboveground part of mycorrhizal corn was higher than that of non-mycorrhizal corn, indicating that the infection of AM fungi changed the P distribution pattern in plant bodies, which is beneficial to increase the salt-resistance of plants.

  16. HAWT dynamic stall response asymmetries under yawed flow conditions

    Energy Technology Data Exchange (ETDEWEB)

    Schreck, S.; Robinson, M.; Hand, M.; Simms, D.

    2000-02-28

    Horizontal axis wind turbines can experience significant time varying aerodynamic loads, potentially causing adverse effects on structures, mechanical components, and power production. As designers attempt lighter and more flexible wind energy machines, greater accuracy and robustness will become even more critical in future aerodynamics models. Aerodynamics modeling advances, in turn, will rely on more thorough comprehension of the three-dimensional, unsteady, vortical flows that dominate wind turbine blade aerodynamics under high load conditions. To experimentally characterize these flows, turbine blade surface pressures were acquired at multiple span locations via the NREL Phase IV Unsteady Aerodynamics Experiment. Surface pressures and associated normal force histories were used to characterize dynamic stall vortex kinematics and normal force amplification. Dynamic stall vortices and normal force amplification were confirmed to occur in response to angle of attack excursions above the static stall threshold. Stall vortices occupied approximately one-half of the blade span and persisted for nearly one-fourth of the blade rotation cycle. Stall vortex convection varied along the blade, resulting in dramatic deformation of the vortex. Presence and deformation of the dynamic stall vortex produced corresponding amplification of normal forces. Analyses revealed consistent alterations to vortex kinematics in response to changes in reduced frequency, span location, and yaw error. Finally, vortex structures and kinematics not previously documented for wind turbine blades were isolated.

  17. STEP Accelerometer Response under Non-Equilibrium Conditions

    Science.gov (United States)

    Wang, S.; Ambekar, P.; Bayart, C.; Torii, R.; Worden, P.; Debra, D.

    The STEP Satellite Test of the Equivalence Principle accelerometer performance is derived under the assumption that the test mass is properly constrained and positioned 5DOF in the housing cavity test mass is in the operational sweet-spot It is extremely useful to check system response when the mass is outside the sweet-spot Using a 1m long fiber suspended test mass we have made past studies on magnetic suspension forces Fy and Fz and have explored the housing cavity in 3DOF x y and z translation limited by uncertainty in test mass tilt angle qy and qz To address this limitation we have recently constructed a 2-axis cryogenic tilt platform The laboratory version of position readout electronics allow us to measure the test mass position at 4K to a precision of 1 nm and tilt angle to less than 1 arc sec in 100 seconds We will present recent experimental data showing the dynamic response of the capacitance measurement subsystem as a function of test mass position

  18. Host plant defense signaling in response to a coevolved herbivore combats introduced herbivore attack

    OpenAIRE

    Woodard, Anastasia M; Ervin, Gary N; Marsico, Travis D

    2012-01-01

    Defense-free space resulting from coevolutionarily naïve host plants recently has been implicated as a factor facilitating invasion success of some insect species. Host plants, however, may not be entirely defenseless against novel herbivore threats. Volatile chemical-mediated defense signaling, which allows plants to mount specific, rapid, and intense responses, may play a role in systems experiencing novel threats. Here we investigate defense responses of host plants to a native and exotic ...

  19. Plant responses to environmental stress: regulation and functions of the Arabidopsis TCH genes

    Science.gov (United States)

    Braam, J.; Sistrunk, M. L.; Polisensky, D. H.; Xu, W.; Purugganan, M. M.; Antosiewicz, D. M.; Campbell, P.; Johnson, K. A.; McIntire, L. V. (Principal Investigator)

    1997-01-01

    Expression of the Arabidopsis TCH genes is markedly upregulated in response to a variety of environmental stimuli including the seemingly innocuous stimulus of touch. Understanding the mechanism(s) and factors that control TCH gene regulation will shed light on the signaling pathways that enable plants to respond to environmental conditions. The TCH proteins include calmodulin, calmodulin-related proteins and a xyloglucan endotransglycosylase. Expression analyses and localization of protein accumulation indicates that the potential sites of TCH protein function include expanding cells and tissues under mechanical strain. We hypothesize that at least a subset of the TCH proteins may collaborate in cell wall biogenesis.

  20. Diverging responses of tropical Andean biomes under future climate conditions.

    Science.gov (United States)

    Tovar, Carolina; Arnillas, Carlos Alberto; Cuesta, Francisco; Buytaert, Wouter

    2013-01-01

    Observations and projections for mountain regions show a strong tendency towards upslope displacement of their biomes under future climate conditions. Because of their climatic and topographic heterogeneity, a more complex response is expected for biodiversity hotspots such as tropical mountain regions. This study analyzes potential changes in the distribution of biomes in the Tropical Andes and identifies target areas for conservation. Biome distribution models were developed using logistic regressions. These models were then coupled to an ensemble of 8 global climate models to project future distribution of the Andean biomes and their uncertainties. We analysed projected changes in extent and elevational range and identified regions most prone to change. Our results show a heterogeneous response to climate change. Although the wetter biomes exhibit an upslope displacement of both the upper and the lower boundaries as expected, most dry biomes tend to show downslope expansion. Despite important losses being projected for several biomes, projections suggest that between 74.8% and 83.1% of the current total Tropical Andes will remain stable, depending on the emission scenario and time horizon. Between 3.3% and 7.6% of the study area is projected to change, mostly towards an increase in vertical structure. For the remaining area (13.1%-17.4%), there is no agreement between model projections. These results challenge the common believe that climate change will lead to an upslope displacement of biome boundaries in mountain regions. Instead, our models project diverging responses, including downslope expansion and large areas projected to remain stable. Lastly, a significant part of the area expected to change is already affected by land use changes, which has important implications for management. This, and the inclusion of a comprehensive uncertainty analysis, will help to inform conservation strategies in the Tropical Andes, and to guide similar assessments for other

  1. The dilemma of saving water or being cool: What determines the stomatal response under a changing climate?

    Science.gov (United States)

    Haghighi, Erfan; Kirchner, James W.; Entekhabi, Dara

    2017-04-01

    Stomata play a critical role in terrestrial water and carbon cycles, regulating the trade-off between photosynthetic carbon gain and water loss in leaves. They adjust their aperture in response to a number of physiological and environmental factors, yet the mechanisms driving this response, particularly under climate extremes, remain poorly understood. Partial or complete stomatal closure reduces plant water stress under water-limited or high atmospheric evaporative demand conditions, but at the cost of reduced productivity, elevated heat, leaf shedding, and mortality. A proper account of such complex stomatal behavior is of particular importance for current ecosystem models that poorly capture observed vegetation responses in the context of climate change which is predicted to cause more frequent and intense temperature extremes along with an increase in the frequency of drought in many regions in the future. This study seeks to explore stomatal responses to environmental change accounted for by a varying soil-plant resistance under different atmospheric and soil moisture conditions. To this end, we developed a physically based transpiration model that couples stomatal control of leaf gas exchange to the leaf surface energy balance and the entire plant hydraulic system by considering the interdependence of the guard cell water potential (or turgor pressure) and transpiration rates. Model simulations of diurnal variations in transpiration rates were in good agreement with field observations, and facilitated quantitative prediction of stomatal and xylem flow regulation under a wide range of environmental conditions. Preliminary results demonstrate how soil and plant hydraulic conductances regulating stomatal opening and closure can help mitigate climatic water deficit (e.g., at midday) by boosting evaporative cooling. Our results are expected to advance physical understanding of the water cycle in the soil-plant-atmosphere continuum, and shed light on observed

  2. Disruption of Ethylene Responses by Turnip mosaic virus Mediates Suppression of Plant Defense against the Green Peach Aphid Vector.

    Science.gov (United States)

    Casteel, Clare L; De Alwis, Manori; Bak, Aurélie; Dong, Haili; Whitham, Steven A; Jander, Georg

    2015-09-01

    Plants employ diverse responses mediated by phytohormones to defend themselves against pathogens and herbivores. Adapted pathogens and herbivores often manipulate these responses to their benefit. Previously, we demonstrated that Turnip mosaic virus (TuMV) infection suppresses callose deposition, an important plant defense induced in response to feeding by its aphid vector, the green peach aphid (Myzus persicae), and increases aphid fecundity compared with uninfected control plants. Further, we determined that production of a single TuMV protein, Nuclear Inclusion a-Protease (NIa-Pro) domain, was responsible for changes in host plant physiology and increased green peach aphid reproduction. To characterize the underlying molecular mechanisms of this phenomenon, we examined the role of three phytohormone signaling pathways, jasmonic acid, salicylic acid, and ethylene (ET), in TuMV-infected Arabidopsis (Arabidopsis thaliana), with or without aphid herbivory. Experiments with Arabidopsis mutants ethylene insensitive2 and ethylene response1, and chemical inhibitors of ET synthesis and perception (aminoethoxyvinyl-glycine and 1-methylcyclopropene, respectively), show that the ET signaling pathway is required for TuMV-mediated suppression of Arabidopsis resistance to the green peach aphid. Additionally, transgenic expression of NIa-Pro in Arabidopsis alters ET responses and suppresses aphid-induced callose formation in an ET-dependent manner. Thus, disruption of ET responses in plants is an additional function of NIa-Pro, a highly conserved potyvirus protein. Virus-induced changes in ET responses may mediate vector-plant interactions more broadly and thus represent a conserved mechanism for increasing transmission by insect vectors across generations. © 2015 American Society of Plant Biologists. All Rights Reserved.

  3. Morphological and Physiological Plant Responses to Drought Stress in Thymus citriodorus

    OpenAIRE

    Zdzislaw Attila Tátrai; Rabab Sanoubar; Zsuzsanna Pluhár; Silvia Mancarella; Francesco Orsini; Giorgio Gianquinto

    2016-01-01

    Water availability is considered as a determinant factor that affects plant growth. The commercial medicinal values of an aromatic plant rely on the presence of secondary metabolites that are affected under water shortage. Two-year-old Thymus citriodorus plants were subjected to different polyethylene glycol (PEG-6000) levels (0, 2%, and 4%) under greenhouse condition. PEG treatment lasted for 15 days. Thyme plant showed a morphological drought avoidance mechanism by maintaining the root syst...

  4. Carrizo citrange Plants Do Not Require the Presence of Roots to Modulate the Response to Osmotic Stress

    Directory of Open Access Journals (Sweden)

    Rosa M. Pérez-Clemente

    2012-01-01

    Full Text Available The study of the effects of a specific stress condition on the performance of plants grown under field conditions is difficult due to interactions among multiple abiotic and biotic factors affecting the system. In vitro tissue-culture-based techniques allow the study of each adverse condition independently and also make possible to investigate the performance of genotypes of interest under stress conditions avoiding the effect of the root. In this paper, the response of Carrizo citrange, a commercial citrus rootstock, to osmotic stress was evaluated by culturing in vitro intact plants and micropropagated shoots. The osmotic stress was generated by adding two different concentrations of polyethyleneglycol to the culture media. Different parameters such as plant performance, organ length, antioxidant activities, and endogenous contents of proline, malondialdehyde, and hormones were determined. Differently to that observed under high salinity, when subjected to osmotic stress conditions, Carrizo citrange showed increased endogenous levels of MDA, proline, and ABA. These results evidence that the mechanisms of response of Carrizo citrange to saline or osmotic stress are different. The presence of roots was not necessary to activate any of the plant responses which indicates that the organs involved in the stress perception and signaling depends on the type of adverse condition to which plants are subjected.

  5. Intracellular trafficking and PIN-mediated cell polarity during tropic responses in plants.

    Science.gov (United States)

    Rakusová, Hana; Fendrych, Matyáš; Friml, Jiří

    2015-02-01

    Subcellular trafficking and cell polarity are basic cellular processes crucial for plant development including tropisms - directional growth responses to environmental stimuli such as light or gravity. Tropisms involve auxin gradient across the stimulated organ that underlies the differential cell elongation and bending. The perception of light or gravity is followed by changes in the polar, cellular distribution of the PIN auxin transporters. Such re-specification of polar trafficking pathways is a part of the mechanism, by which plants adjust their phenotype to environmental changes. Recent genetic and biochemical studies provided the important insights into mechanisms of PIN polarization during tropisms. In this review, we summarize the present state of knowledge on dynamic PIN repolarization and its specific regulations during hypocotyl tropisms. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Fiber optic spectrophotometry monitoring of plant nutrient deficiency under hydroponic culture conditions

    Science.gov (United States)

    Liew, Oi Wah; Boey, William S. L.; Asundi, Anand K.; Chen, Jun-Wei; He, Duo-Min

    1999-05-01

    In this paper, fiber optic spectrophotometry (FOSpectr) was adapted to provide early detection of plant nutrient deficiency by measuring leaf spectral reflectance variation resulting from nutrient stress. Leaf reflectance data were obtained form a local vegetable crop, Brassica chinensis var parachinensis (Bailey), grown in nitrate-nitrogen (N)- and calcium (Ca)- deficient hydroponics nutrient solution. FOSpectr analysis showed significant differences in leaf reflectance within the first four days after subjecting plants to nutrient-deficient media. Recovery of the nutrient-stressed plants could also be detected after transferring them back to complete nutrient solution. In contrast to FOSpectr, plant response to nitrogen and calcium deficiency in terms of reduced growth and tissue elemental levels was slower and less pronounced. Thus, this study demonstrated the feasibility of using FOSpectr methodology as a non-destructive alternative to augment current methods of plant nutrient analysis.

  7. Probabilistic assessment of the Juragua NPP response under Station Blackout conditions

    International Nuclear Information System (INIS)

    Valhuerdi Debesa, C.; Vilaragut Llanes, J.J.

    1996-01-01

    Assessment of the NPP response under SBO (station Blackout) conditions is a current safety issue of special interest, In the case of Juragua NPP, the safety assessment related to this topic is very important, taking into account the peculiarities of the Cuban Electro energetic System: small and long island, without possibilities of conexion beyond its borders and under the incidence of tropical phenomena In this papers a preliminary evaluation is presented of the potential incidence of Station Blackout conditions for Juragua NPP. the importance of this sort of events for the safety of the plant is evaluated, the factors which condition it are identified and measures for its prevention or recovering the normal situation if such an event takes place are proposed

  8. Morpho-physiological and productive biometry in semi-erect cultivars of the cowpea under different plant populations

    Directory of Open Access Journals (Sweden)

    Antônio Aécio de Carvalho Bezerra

    Full Text Available ABSTRACT The aim of this study was to evaluate morpho-physiological and productive characteristics in four semi-erect cultivars of the cowpea under five plant populations. The experiment was conducted in the experimental area of Embrapa Meio-Norte in Teresina in the State of Piauí, Brazil (PI. The experimental design was of randomised complete blocks with four replications, in a 4 x 5 factorial scheme, for evaluating four cultivars (BRS Guariba, BRS Novaera, BRS Potengi and BRS Tumucumaque and five plant populations (105, 2x105, 3x105, 4x105 and 5x105 plants ha-1. There were significant differences between cultivars for primary branch length (PBL, number of lateral branches (NLB, 100-grain weight (HGW, and dry-grain yield (GY. The maximum PBL of 58.5 cm was obtained with 300 thousand plants ha-1, corresponding to an increase of 11.5% when compared to 100 thousand plants ha-1. However, there was a reduction of 91.2% in NLB when compared to the populations of 100 and 500 thousand plants ha-1. The increases of 188% obtained in the leaf area index (LAI in the range of 100 to 500 thousand plants ha-1 explain the linear increase in the crop growth rate (CGR as being due to the greater production of leaf area; also, the decreases seen in the net assimilation rate (NAR, especially in the range of 100 to 300 thousand plants ha-1, are explained as due to the consequent self-shading, which was intensified in the larger populations. LAI, light interception, and CGR in the cultivars increase in response to higher densities. HGW and GY are not significantly affected by the different populations.

  9. Mechanisms underlying plant sexual dimorphism in multi-trophic arthropod communities.

    Science.gov (United States)

    Petry, William K; Perry, Kayla I; Fremgen, Aleshia; Rudeen, Sarahi K; Lopez, Mitchell; Dryburgh, John; Mooney, Kailen A

    2013-09-01

    A growing body of research documents the importance of plant genetic effects on arthropod community structure. However, the mechanisms underlying these effects are often unclear. Additionally, plant genetic effects have largely been quantified in common gardens, thus inflating the estimates of their importance by minimizing levels of natural variation. Using Valeriana edulis, a dioecious plant with genetically based sex determination, we conducted surveys and experiments on wild-grown individuals to document field patterns of arthropod association between the sexes and the mechanisms underlying these plant genetic effects. Three years of surveys revealed strong and consistent sex-biased arthropod association in wild-grown plants: female plants supported 4-fold, 1.5-fold, and 4-fold higher densities of aphids, aphid predators, and aphid-tending ants, respectively, compared to males. There was mixed evidence that the female bias for aphids was due to higher plant quality, while we found no difference between plant sexes in aphid preference or the top-down effects of predators and tending ants. Female bias for ants was due to both the greater attractiveness of female plants (direct effect mediated by floral nectar) and an independent, weaker effect of higher aphid abundance on females (density-mediated indirect effect). Conversely, the female bias for predators was driven solely by the greater attractiveness of female plants. We did not find interaction modification, i.e., ant-aphid and predator-aphid interactions were equivalent between plant sexes. Plant sex explained 0.24%, 2.28%, and 4.42% of the variance in aphids, predators, and ants, respectively, values comparable to but slightly weaker than those previously reported from common-garden studies. In contrast to the prediction of diminished plant genetic effects with increasing trophic level, we show how weak indirect effects on predators and parasitoids (via herbivores) can be complemented by strong direct

  10. GSTF1 Gene Expression Analysis in Cultivated Wheat Plants under Salinity and ABA Treatments

    OpenAIRE

    Ali Niazi; Amin Ramezani; Ali Dinari

    2014-01-01

    Most plants encounter stress such as drought and salinity that adversely affect growth, development and crop productivity. The expression of the gene glutathione-s-transferases (GST) extends throughout various protective mechanisms in plants and allows them to adapt to unfavorable environmental conditions. GSTF1 (the first phi GSTFs class) gene expression patterns in the wheat cultivars Mahuti and Alamut were studied under salt and ABA treatments using a qRT-PCR technique. Results showed that...

  11. The Minitron system for growth of small plants under controlled environment conditions

    Science.gov (United States)

    Akers, Carolyn P.; Akers, Stuart W.; Mitchell, Cary A.

    1985-01-01

    The design and operation of a system is described in which small plants can be grown under controlled environment conditions. Important features of this 'Minitron' system include precise control of temperature and CO2 concentration in a flowing atmosphere. Plants can be grown either hydroponically or in solid root support medium. For either culture method, nutrient solution or water is added from an external reservoir, altering neither atmospheric composition nor temperature equilibrium within a closed Minitron chamber.

  12. The response of Acacia karroo plants to defoliation by hand ...

    African Journals Online (AJOL)

    Shoot production of all plants defoliated by hand was no different to that of the undefoliated control plants and was considerably less than that of the plants defoliated by goats. Keywords: acacia karroo; browse production; browsing; clipping; defoliation; goats; growth stimulation; leaf growth; leaves; shoot growth; shoot ...

  13. Plant transcriptomics and responses to environmental stress: an ...

    Indian Academy of Sciences (India)

    Abstract. Different stresses include nutrient deficiency, pathogen attack, exposure to toxic chemicals etc. Transcriptomic studies have been mainly applied to only a few plant species including the model plant, Arabidopsis thaliana. These studies have pro- vided valuable insights into the genetic networks of plant stress ...

  14. Plant eco-physiological responses to multiple environmental and climate changes

    Energy Technology Data Exchange (ETDEWEB)

    Rost Albert, K.

    2009-03-15

    }; 6) Photosynthetic capacity were closely linked to growth strategy and rewetting stimulation were closely related to high nitrogen leaf content; 7) Responses to elevated CO{sub 2}, drought and warming could not be deduced from single factor experiments; 8) Ambient UV-B decreased PSII performance despite stimulation of UV-B absorbing compounds in high arctic plants in both short and long term; 9) Ambient UV-B decreased net photosynthesis via effects on PSII performance in combination with effects on Calvin Cycle; 10) Current UV-B level is a important factor affecting high arctic plants, particularly in years with spring advancement induced by warming. In conclusion, the results in this thesis suggest the responses of temperate heath plant photosynthesis to be imitatively linked with plant growth strategy and water relations, and also that the responses of photosynthesis to the important drivers often interacted. Current UV-B levels decreases productivity in high arctic heath plants, and advanced spring in response to warming may lead to further decrease while other climatic changes as elevated CO{sub 2} may negate this. Stimulated productivity of temperate heath plants is likely under the climatic conditions predicted to be prevailing in Denmark anno 2075. (author)

  15. Effects of planting density and drought on the productivity of tea clones ( Camellia sinensis L.): Yield responses

    Science.gov (United States)

    Kigalu, Julius M.

    Tea is an important cash crop in Tanzania, contributing over US$ 45 million of annual exports and grown by over 30 000 smallholder households, and a further 10 000 people are employed by large estate producers. Over 70% of the national tea production comes from the Southern Highlands of Tanzania where expansion of tea estates under limited suitable land for tea is expected for the next two decades. Thus a client-demand driven field experiment was established in January 1993 to study and advice tea growers on the effects of plant density on the productivity and water use of young tea. The experiment comprised of two types of vegetative propagated tea plants (known as “clones”) of contrasting growth behaviour (AHP S15/10: spreading type and BBK35: erect), six plant densities (labelled D1: 8300 plants ha -1 to D6: 83 300 plants ha -1) and seven irrigation or drought levels (labelled I0: un irrigated, to I6: well irrigated condition) as the treatments. Clone AHP S15/10, with larger crop cover than clone BBK35, consistently out-yielded clone BBK35 at all densities and under both well watered and drought stressed conditions. The corresponding yields from clone BBK35 were 2620 and 5960 kg ha -1. Reciprocal of yield per plant- and asymptotic yield-density relationships were used to explain these responses to density. Yields from clone AHP S15/10 during the period of drought treatments decreased as the maximum soil water deficit increased at all densities, but there were no yield responses to drought from clone BBK35 at the low densities. The study recommends planting densities of 20 000 and 40 000 plants ha -1 for clones AHP S15/10, respectively for well irrigated conditions and a density of 20 000 plants ha -1 for both clones under un-irrigated environments.

  16. Morphophysiological plasticity of plagiotropic branches in response to change in the coffee plant spacing within rows

    Directory of Open Access Journals (Sweden)

    Cláudio Pagotto Ronchi

    2016-12-01

    node but not in the number of fruiting nodes per branch. Although this response was largely cultivar-dependent, it also changed according to the branch position in the hedgerow. Our results suggest that all tested cultivars exhibit high morphophysiological plasticity and have the potential to grow under different plant spacing within rows.

  17. Thermal equilibrium responses in Guzerat cattle raised under tropical conditions.

    Science.gov (United States)

    Camerro, Leandro Zuccherato; Maia, Alex Sandro Campos; Neto, Marcos Chiquitelli; Costa, Cintia Carol de Melo; Castro, Patric André

    2016-08-01

    The literature is very sparse regarding research on the thermal equilibrium in Guzerat cattle (Bos indicus) under field conditions. Some factors can modify the physiological response of Guzerat cattle, such as the reactivity of these animals to handling. Thus, the development of a methodology to condition and select Guzerat cattle to acclimate them to the routine collection of data without altering their physiological response was the objective of the preliminary experiment. Furthermore, the animals selected were used in the main experiment to determine their thermal equilibrium according to the thermal environment. For this proposal, the metabolic heat production and heat exchange between the animal and the environment were measured simultaneously in the field with an indirect calorimetry system coupled to a facial mask. The results of the preliminary experiment showed that the respiratory rate could demonstrate that conditioning efficiently reduced the reactivity of the animals to experimental handling. Furthermore, the respiratory rate can be used to select animals with less reactivity. The results of the main experiment demonstrate that the skin, hair-coat surface and expired air temperature depend on the air temperature, whereas the rectal temperature depends on the time of day; consequently, the sensible heat flow was substantially reduced from 70 to 20Wm(-2) when the air temperature increased from 24 to 34°C. However, the respiratory latent heat flow increased from 10 to 15Wm(-2) with the same temperature increase. Furthermore, the metabolic heat production remained stable, independent of the variation of the air temperature; however, it was higher in males than in females (by approximately 25%). This fact can be explained by the variation of the ventilation rate, which had a mean value of 1.6 and 2.2Ls(-1) for females and males, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. The Utilization of Plant Facilities on the International Space Station—The Composition, Growth, and Development of Plant Cell Walls under Microgravity Conditions

    Directory of Open Access Journals (Sweden)

    Ann-Iren Kittang Jost

    2015-01-01

    Full Text Available In the preparation for missions to Mars, basic knowledge of the mechanisms of growth and development of living plants under microgravity (micro-g conditions is essential. Focus has centered on the g-effects on rigidity, including mechanisms of signal perception, transduction, and response in gravity resistance. These components of gravity resistance are linked to the evolution and acquisition of responses to various mechanical stresses. An overview is given both on the basic effect of hypergravity as well as of micro-g conditions in the cell wall changes. The review includes plant experiments in the US Space Shuttle and the effect of short space stays (8–14 days on single cells (plant protoplasts. Regeneration of protoplasts is dependent on cortical microtubules to orient the nascent cellulose microfibrils in the cell wall. The space protoplast experiments demonstrated that the regeneration capacity of protoplasts was retarded. Two critical factors are the basis for longer space experiments: a. the effects of gravity on the molecular mechanisms for cell wall development, b. the availability of facilities and hardware for performing cell wall experiments in space and return of RNA/DNA back to the Earth. Linked to these aspects is a description of existing hardware functioning on the International Space Station.

  19. Effect of drought and rewatering on the cellular status and antioxidant response of Medicago truncatula plants.

    Science.gov (United States)

    Filippou, Panagiota; Antoniou, Chrystalla; Fotopoulos, Vasileios

    2011-02-01

    Effects of water stress on plants have been well-documented. However, the combined responses to drought and rewatering and their underlying mechanisms are relatively unknown. The present study attempts to describe spatiotemporal alterations in the physiology and cellular status of Medicago truncatula tissues that result from and subsequently follow a period of moderate water deficit. Physiological processes and cellular damage levels were monitored in roots and leaves by determining lipid peroxidation levels, as well as nitric oxide and hydrogen peroxide content, further supported by stomatal conductance and chlorophyll fluorescence measurements in leaves. During water stress, cells in both organs displayed increased damage levels and reactive oxygen and nitrogen species content, while leaves showed reduced stomatal conductance. Furthermore, both tissues demonstrated increased proline content. Upon rewatering, plants recovered displaying readings similar to pre-stress control conditions. Furthermore, molecular analysis of antioxidant gene expression by quantitative real-time RT-PCR revealed differential spatiotemporal regulation in a number of genes examined (including catalase, cytosolic ascorbate peroxidase, copper/zinc and iron superoxide dismutase and alternative oxidase). Overall, M. truncatula plants demonstrated increased sensitivity to drought-induced oxidative damage; however, this was reversed following rewatering indicating a great elasticity in the plant's capacity to cope with free oxygen radicals. 

  20. Growth and gas exchanges of arugula plants under silicon fertilization and water restriction

    Directory of Open Access Journals (Sweden)

    Edmar G. de Jesus

    Full Text Available ABSTRACT The objective of this article was to study the growth and gas exchange of arugula plants under silicon (Si fertilization and water stress. The experiment was installed in a greenhouse, located in the municipality of Pombal, PB, Brazil, whose geographic coordinates are 6º 46 ‘S latitude and 37º 49’ W longitude and 178 m of altitude, situated in the 'Sertão Paraibano' micro-region. The experimental design was in randomized blocks, in 5 x 2 factorial scheme, corresponding to five Si doses (0, 50, 100, 150 and 200 mg L-1 and two irrigation depths [50 and 100% of real evapotranspiration (ETr based on weighing lysimeter], with four replicates. Silicon application was performed as foliar spray, using a commercial product composed of 0.75% Si and 0.15% Mo. Arugula growth and gas exchange was evaluated. Higher values for number of leaves and plant height were obtained in plants cultivated under 100% ETr. Silicon application between 100 and 120 mg L-1 led to better results in the physiological variables of arugula plants under water stress. Silicon application between 30 and 60 mg L-1 in arugula plants under 100% ETr irrigation allowed greater phytomass accumulation.

  1. Effect of silicon addition on soybean (Glycine max) and cucumber (Cucumis sativus) plants grown under iron deficiency.

    Science.gov (United States)

    Gonzalo, María José; Lucena, Juan J; Hernández-Apaolaza, Lourdes

    2013-09-01

    Silicon is considered an essential element in several crops enhancing growth and alleviating different biotic and abiotic stresses. In this work, the role of Si in the alleviation of iron deficiency symptoms and in the Fe distribution in iron deficient plants has been studied. Thus, soybean and cucumber plants grown in hydroponic culture under iron limiting conditions were treated with different Si doses (0.0, 0.5 and 1.0 mM). The use of a strong chelating agent such as HBED avoided Fe co-precipitation in the nutrient solution and allowed for the first time the analysis of Si effect in iron nutrition without the interference of the iron rhizospheric precipitation. SPAD index, plant growth parameters and mineral content in plant organs were determined. For soybean, the addition of 0.5 mM of Si to the nutrient solution without iron, initially or continuously during the experiment, prevented the chlorophyll degradation, slowed down the growth decrease due to the iron deficiency and maintained the Fe content in leaves. In cucumber, Si addition delayed the decrease of stem dry weight, stem length, node number and iron content in stems and roots independently of the dose, but no-effect was observed in chlorosis symptoms alleviation in leaves. The observed response to Si addition in iron deficiency was plant-specific, probably related with the different Fe efficiency strategies developed by these two species. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  2. Pseudomonas putida response in membrane bioreactors under salicylic acid-induced stress conditions

    Energy Technology Data Exchange (ETDEWEB)

    Collado, Sergio; Rosas, Irene; González, Elena; Gutierrez-Lavin, Antonio; Diaz, Mario, E-mail: mariodiaz@uniovi.es

    2014-02-01

    Highlights: • MBR under feed-induced stress conditions: starvation and changing feeding conditions. • High capacity of MBR to withstand high variations in feed loads. • Slow biofilm formation under starvation conditions during the first days. • Observed growth of P. putida for substrate to microorganism ratio higher than 0.6 g/g. • Maximum specific growth rate and growth yield values of around 37.5 h{sup −1} and 0.5 g/g. - Abstract: Starvation and changing feeding conditions are frequently characteristics of wastewater treatment plants. They are typical causes of unsteady-state operation of biological systems and provoke cellular stress. The response of a membrane bioreactor functioning under feed-induced stress conditions is studied here. In order to simplify and considerably amplify the response to stress and to obtain a reference model, a pure culture of Pseudomonas putida was selected instead of an activated sludge and a sole substrate (salicylic acid) was employed. The system degraded salicylic acid at 100–1100 mg/L with a high level of efficiency, showed rapid acclimation without substrate or product inhibition phenomena and good stability in response to unsteady states caused by feed variations. Under starvation conditions, specific degradation rates of around 15 mg/g h were achieved during the adaptation of the biomass to the new conditions and no biofilm formation was observed during the first days of experimentation using an initial substrate to microorganisms ratio lower than 0.1. When substrate was added to the reactor as pulses resulting in rapidly changing concentrations, P. putida growth was observed only for substrate to microorganism ratios higher than 0.6, with a maximum Y{sub X/S} of 0.5 g/g. Biofilm development under changing feeding conditions was fast, biomass detachment only being significant for biomass concentrations on the membrane surface that were higher than 16 g/m{sup 2}.

  3. Pseudomonas putida response in membrane bioreactors under salicylic acid-induced stress conditions

    International Nuclear Information System (INIS)

    Collado, Sergio; Rosas, Irene; González, Elena; Gutierrez-Lavin, Antonio; Diaz, Mario

    2014-01-01

    Highlights: • MBR under feed-induced stress conditions: starvation and changing feeding conditions. • High capacity of MBR to withstand high variations in feed loads. • Slow biofilm formation under starvation conditions during the first days. • Observed growth of P. putida for substrate to microorganism ratio higher than 0.6 g/g. • Maximum specific growth rate and growth yield values of around 37.5 h −1 and 0.5 g/g. - Abstract: Starvation and changing feeding conditions are frequently characteristics of wastewater treatment plants. They are typical causes of unsteady-state operation of biological systems and provoke cellular stress. The response of a membrane bioreactor functioning under feed-induced stress conditions is studied here. In order to simplify and considerably amplify the response to stress and to obtain a reference model, a pure culture of Pseudomonas putida was selected instead of an activated sludge and a sole substrate (salicylic acid) was employed. The system degraded salicylic acid at 100–1100 mg/L with a high level of efficiency, showed rapid acclimation without substrate or product inhibition phenomena and good stability in response to unsteady states caused by feed variations. Under starvation conditions, specific degradation rates of around 15 mg/g h were achieved during the adaptation of the biomass to the new conditions and no biofilm formation was observed during the first days of experimentation using an initial substrate to microorganisms ratio lower than 0.1. When substrate was added to the reactor as pulses resulting in rapidly changing concentrations, P. putida growth was observed only for substrate to microorganism ratios higher than 0.6, with a maximum Y X/S of 0.5 g/g. Biofilm development under changing feeding conditions was fast, biomass detachment only being significant for biomass concentrations on the membrane surface that were higher than 16 g/m 2

  4. Stress responses of spring rape plants to soil flooding

    Science.gov (United States)

    Balakhnina, T.; Bennicelli, R.; Stêpniewska, Z.; Stêpniewski, W.; Borkowska, A.; Fomina, I.

    2012-10-01

    Stress responses of spring rape to soil hypoxia were investigated during 8-days flooding. Soil air-filled porosity decreased from 25-30% to 0%, oxygen diffusion rate - from 2.6-3.5 to 0.34 μmol O2 m-2 s-1, and redox potential - from 460 to 150mVwithin few hours. Alcohol dehydrogenase activity in roots increased up to 7-fold after one day of flooding and then decreased to 170% of control. Superoxide dismutase activity in roots increased by 27% during first 3 days and then dropped to 60% of control; in the leaves superoxide dismutase activity increased in average by 44%. Ascorbate peroxidase activity in leaves increased by 37% during first 3 days and then decreased to control value. Glutathione reductase activity increased by 45% in roots of flooded plants but did not change in leaves. Proline concentration in leaves increased up to 4-fold on the 3d day of flooding and then decreased to control value. Thus soil flooding induces increase of alcohol dehydrogenase activity and subsequent increase of superoxide dismutase and glutathione reductase activities in roots while the leaves display a few days increase of free proline concentration and ascorbate peroxidase activity, and a long-term increase of superoxide dismutase activity.

  5. Elevation gradient of successful plant traits for colonizing alpine summits under climate change

    International Nuclear Information System (INIS)

    Matteodo, Magalì; Wipf, Sonja; Stöckli, Veronika; Rixen, Christian; Vittoz, Pascal

    2013-01-01

    Upward migration of plant species due to climate change has become evident in several European mountain ranges. It is still, however, unclear whether certain plant traits increase the probability that a species will colonize mountain summits or vanish, and whether these traits differ with elevation. Here, we used data from a repeat survey of the occurrence of plant species on 120 summits, ranging from 2449 to 3418 m asl, in south-eastern Switzerland to identify plant traits that increase the probability of colonization or extinction in the 20th century. Species numbers increased across all plant traits considered. With some traits, however, numbers increased proportionally more. The most successful colonizers seemed to prefer warmer temperatures and well-developed soils. They produced achene fruits and/or seeds with pappus appendages. Conversely, cushion plants and species with capsule fruits were less efficient as colonizers. Observed changes in traits along the elevation gradient mainly corresponded to the natural distribution of traits. Extinctions did not seem to be clearly related to any trait. Our study showed that plant traits varied along both temporal and elevational gradients. While seeds with pappus seemed to be advantageous for colonization, most of the trait changes also mirrored previous gradients of traits along elevation and hence illustrated the general upward migration of plant species. An understanding of the trait characteristics of colonizing species is crucial for predicting future changes in mountain vegetation under climate change. (letter)

  6. Improvement in the bioenergetics system of plants under metal stress environment via seaweeds

    International Nuclear Information System (INIS)

    Azmat, R.; Askari, S.

    2015-01-01

    The effects of Hg and its remediation through seaweeds on seedlings were escorted in a greenhouse experiment in a randomized block design. The effects of Hg were monitored in relation with bioenergetics system of Trigonella foenumgraecum plant at test site scale. Plants that were exposed to Hg, showed affect in diverse ways, including affinity to suffer in morphological as well as on sugar metabolism. The stress imposed by Hg exposure also extends to chloroplast pigments that lead to the distorted photosynthetic apparatus. The outcomes of reduced contents of photosynthetic machinery related with reduced contents of glucose, sucrose, total soluble sugars and carbohydrate contents of plants. These contents plays vital rule for providing bioenergy to the plant growth regulation. It was suggested that Hg is lethal for plant bioenergetics system due to which plants fail to survive under stress. The lethal effects of Hg were tried to remediate through green seaweeds (Codium iyengrii). It was observed that seaweeds successfully controlled the mobility of Hg metal and improves the plant growth regulatory system at lower applied dose only. While at higher dose of Hg, seaweeds were also effective but to a certain limits. It was established that continuous addition of Hg in soil and aquatic resources execute to the plant productivity. It is demand of time to develop alternative eco-friendly remediation technologies for controlling, cleaning Hg-polluted zones. (author)

  7. Modeling of the response under radiation of electronic dosemeters

    International Nuclear Information System (INIS)

    Menard, S.

    2003-01-01

    The simulation with with calculation codes the interactions and the transport of primary and secondary radiations in the detectors allows to reduce the number of developed prototypes and the number of experiments under radiation. The simulation makes possible the determination of the response of the instrument for exposure configurations more extended that these ones of references radiations produced in laboratories. The M.C.N.P.X. allows to transport, over the photons, electrons and neutrons, the charged particles heavier than the electrons and to simulate the radiation - matter interactions for a certain number of particles. The present paper aims to present the interest of the use of the M.C.N.P.X. code in the study, research and evaluation phases of the instrumentation necessary to the dosimetry monitoring. To do that the presentation gives the results of the modeling of a prototype of a equivalent tissue proportional counter (C.P.E.T.) and of the C.R.A.M.A.L. ( radiation protection apparatus marketed by the Eurisys Mesures society). (N.C.)

  8. Conservation of the piezoelectric response of PVDF films under irradiation

    Science.gov (United States)

    Melilli, G.; Lairez, D.; Gorse, D.; Garcia-Caurel, E.; Peinado, A.; Cavani, O.; Boizot, B.; Clochard, M.-C.

    2018-01-01

    As opposed to piezo-ceramics (i.e PZT), flexibility and robustness characterize piezoelectric polymers. The main advantage of a piezoelectric polymer, such as Poly (vinylidene fluoride) (PVDF), is an electric power generation under large reversible elastic deformation. Starting from polarized PVDF, we have shown that, despite the fact that irradiation is known to structurally modify the PVDF by introducing defects (radicals, chain scission and crosslinks), the electro-active properties were not affected. At doses lower than 100 kGy, a comparison between swift heavy-ion (SHI) and e-beam irradiations is presented. A homemade device was realized to measure the output voltage as a function of the bending deformation for irradiated and non-irradiated PVDF film. DSC and FT-IR techniques give new insights on which crystalline part or structural change contributes to the conservation of the output voltage. Results suggest that despite the material after irradiation is composed of smaller crystallites, the β-phase content remains stable around 36%, which explains the remarkable preservation of the piezoelectric response in irradiated polarized PVDF films.

  9. RNA-seq analysis of the response of the halophyte, Mesembryanthemum crystallinum (ice plant to high salinity.

    Directory of Open Access Journals (Sweden)

    Hironaka Tsukagoshi

    Full Text Available Understanding the molecular mechanisms that convey salt tolerance in plants is a crucial issue for increasing crop yield. The ice plant (Mesembryanthemum crystallinum is a halophyte that is capable of growing under high salt conditions. For example, the roots of ice plant seedlings continue to grow in 140 mM NaCl, a salt concentration that completely inhibits Arabidopsis thaliana root growth. Identifying the molecular mechanisms responsible for this high level of salt tolerance in a halophyte has the potential of revealing tolerance mechanisms that have been evolutionarily successful. In the present study, deep sequencing (RNAseq was used to examine gene expression in ice plant roots treated with various concentrations of NaCl. Sequencing resulted in the identification of 53,516 contigs, 10,818 of which were orthologs of Arabidopsis genes. In addition to the expression analysis, a web-based ice plant database was constructed that allows broad public access to the data. The results obtained from an analysis of the RNAseq data were confirmed by RT-qPCR. Novel patterns of gene expression in response to high salinity within 24 hours were identified in the ice plant when the RNAseq data from the ice plant was compared to gene expression data obtained from Arabidopsis plants exposed to high salt. Although ABA responsive genes and a sodium transporter protein (HKT1, are up-regulated and down-regulated respectively in both Arabidopsis and the ice plant; peroxidase genes exhibit opposite responses. The results of this study provide an important first step towards analyzing environmental tolerance mechanisms in a non-model organism and provide a useful dataset for predicting novel gene functions.

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

    Science.gov (United States)

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

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

  11. Dynamic response of high speed centrifuge for reprocessing plant

    International Nuclear Information System (INIS)

    Rajput, Gaurav; Satish Kumar, V.; Selvaraj, T.; Ananda Rao, S.M.; Ravisankar, A.

    2012-01-01

    The standard for balancing the rotating bowl describes only the details about the selection of balance quality grade and the permissible residual unbalance for different operating speeds. This paper presents the effects of unbalance on the rotating bowl of high speed centrifuge used in reprocessing of spent nuclear fuel. In this study, the residual unbalance is evaluated for different recommended balancing grades in accordance with the ISO 1940. This unbalance mass generates dynamic force which acts on the rotor. The dynamic response of the rotor like displacements and stresses under this dynamic force are studied by numerical simulation. Finally, the effect of residual unbalance on the rotating bowl performance for different balancing grades is discussed. The experimental measurements are also carried out for the case of G 1.0 grade balanced rotating bowl to validate the resonance frequency as well as vibration amplitudes. (author)

  12. Soil nitrogen dynamics and Capsicum Annuum sp. plant response to biochar amendment in silt loam soil

    Science.gov (United States)

    Horel, Agota; Gelybo, Gyorgyi; Dencso, Marton; Toth, Eszter; Farkas, Csilla; Kasa, Ilona; Pokovai, Klara

    2017-04-01

    The present study investigated the growth of Capsicum Annuum sp. (pepper) in small-scale experiment to observe changes in plant growth and health as reflected by leaf area, plant height, yield, root density, and nitrogen usage. Based on field conditions, part of the study aimed to examine the photosynthetic and photochemical responses of plants to treatments resulting from different plant growth rates. During the 12.5 week long study, four treatments were investigated with biochar amount of 0, 0.5%, 2.5%, and 5.0% (by weight) added to silt loam soil. The plants were placed under natural environmental conditions, such that photosynthetic activities from photosynthetically active radiation (PAR) and the plants photochemical reflectance index (PRI) could be continuously measured after exposure to sunlight. In this study we found that benefits from biochar addition to silt loam soil most distinguishable occurred in the BC2.5 treatments, where the highest plant yield, highest root density, and highest leaf areas were observed compared to other treatments. Furthermore, data showed that too low (0.5%) or too high (5.0%) biochar addition to the soil had diminishing effects on Capsicum Annuum sp. growth and yield over time. At the end of the 12th week, BC2.5 had 22.2%, while BC0.5 and BC5.0 showed 17.4% and 15.7% increase in yield dry weight respectively compared to controls. The collected data also showed that the PRI values of plants growing on biochar treated soils were generally lower compared to control treatments, which could relate to leaf nitrogen levels. Total nitrogen amount showed marginal changes over time in all treatments. The total nitrogen concentration showed 28.6% and 17.7% increase after the 6th week of the experiment for BC2.5 and BC5.0, respectively, while inorganic nutrients of NO3-N and NH4+-N showed a continuous decrease during the course of the study, with a substantial drop during the first few weeks. The present study provides evidence for impact

  13. Sugar signalling and gene expression in relation to carbohydrate metabolism under abiotic stresses in plants.

    Science.gov (United States)

    Gupta, Anil K; Kaur, Narinder

    2005-12-01

    Sucrose is required for plant growth and development. The sugar status of plant cells is sensed by sensor proteins. The signal generated by signal transduction cascades, which could involve mitogen-activated protein kinases, protein phosphatases, Ca 2+ and calmodulins, results in appropriate gene expression. A variety of genes are either induced or repressed depending upon the status of soluble sugars. Abiotic stresses to plants result in major alterations in sugar status and hence affect the expression of various genes by down- and up-regulating their expression. Hexokinase-dependent and hexokinase-independent pathways are involved in sugar sensing. Sucrose also acts as a signal molecule as it affects the activity of a proton-sucrose symporter. The sucrose trans-porter acts as a sucrose sensor and is involved in phloem loading. Fructokinase may represent an additional sensor that bypasses hexokinase phosphorylation especially when sucrose synthase is dominant. Mutants isolated on the basis of response of germination and seedling growth to sugars and reporter-based screening protocols are being used to study the response of altered sugar status on gene expression. Common cis-acting elements in sugar signalling pathways have been identified. Transgenic plants with elevated levels of sugars/sugar alcohols like fructans, raffinose series oligosaccharides, trehalose and mannitol are tolerant to different stresses but have usually impaired growth. Efforts need to be made to have transgenic plants in which abiotic stress responsive genes are expressed only at the time of adverse environmental conditions instead of being constitutively synthesized.

  14. A nucleotide metabolite controls stress-responsive gene expression and plant development.

    Directory of Open Access Journals (Sweden)

    Hao Chen

    Full Text Available Abiotic stress, such as drought and high salinity, activates a network of signaling cascades that lead to the expression of many stress-responsive genes in plants. The Arabidopsis FIERY1 (FRY1 protein is a negative regulator of stress and abscisic acid (ABA signaling and exhibits both an inositol polyphosphatase and a 3',5'-bisphosphate nucleotidase activity in vitro. The FRY1 nucleotidase degrades the sulfation byproduct 3'-phosphoadenosine-5'-phosphate (PAP, yet its in vivo functions and particularly its roles in stress gene regulation remain unclear. Here we developed a LC-MS/MS method to quantitatively measure PAP levels in plants and investigated the roles of this nucleotidase activity in stress response and plant development. It was found that PAP level was tightly controlled in plants and did not accumulate to any significant level either under normal conditions or under NaCl, LiCl, cold, or ABA treatments. In contrast, high levels of PAP were detected in multiple mutant alleles of FRY1 but not in mutants of other FRY1 family members, indicating that FRY1 is the major enzyme that hydrolyzes PAP in vivo. By genetically reducing PAP levels in fry1 mutants either through overexpression of a yeast PAP nucleotidase or by generating a triple mutant of fry1 apk1 apk2 that is defective in the biosynthesis of the PAP precursor 3'-phosphoadenosine-5'-phosphosulfate (PAPS, we demonstrated that the developmental defects and superinduction of stress-responsive genes in fry1 mutants correlate with PAP accumulation in planta. We also found that the hypersensitive stress gene regulation in fry1 requires ABH1 but not ABI1, two other negative regulators in ABA signaling pathways. Unlike in yeast, however, FRY1 overexpression in Arabidopsis could not enhance salt tolerance. Taken together, our results demonstrate that PAP is critical for stress gene regulation and plant development, yet the FRY1 nucleotidase that catabolizes PAP may not be an in vivo salt

  15. A nucleotide metabolite controls stress-responsive gene expression and plant development

    KAUST Repository

    Chen, Hao

    2011-10-19

    Abiotic stress, such as drought and high salinity, activates a network of signaling cascades that lead to the expression of many stress-responsive genes in plants. The Arabidopsis FIERY1 (FRY1) protein is a negative regulator of stress and abscisic acid (ABA) signaling and exhibits both an inositol polyphosphatase and a 3?,5?-bisphosphate nucleotidase activity in vitro. The FRY1 nucleotidase degrades the sulfation byproduct 3?-phosphoadenosine-5?-phosphate (PAP), yet its in vivo functions and particularly its roles in stress gene regulation remain unclear. Here we developed a LC-MS/MS method to quantitatively measure PAP levels in plants and investigated the roles of this nucleotidase activity in stress response and plant development. It was found that PAP level was tightly controlled in plants and did not accumulate to any significant level either under normal conditions or under NaCl, LiCl, cold, or ABA treatments. In contrast, high levels of PAP were detected in multiple mutant alleles of FRY1 but not in mutants of other FRY1 family members, indicating that FRY1 is the major enzyme that hydrolyzes PAP in vivo. By genetically reducing PAP levels in fry1 mutants either through overexpression of a yeast PAP nucleotidase or by generating a triple mutant of fry1 apk1 apk2 that is defective in the biosynthesis of the PAP precursor 3?-phosphoadenosine-5?-phosphosulfate (PAPS), we demonstrated that the developmental defects and superinduction of stress-responsive genes in fry1 mutants correlate with PAP accumulation in planta. We also found that the hypersensitive stress gene regulation in fry1 requires ABH1 but not ABI1, two other negative regulators in ABA signaling pathways. Unlike in yeast, however, FRY1 overexpression in Arabidopsis could not enhance salt tolerance. Taken together, our results demonstrate that PAP is critical for stress gene regulation and plant development, yet the FRY1 nucleotidase that catabolizes PAP may not be an in vivo salt toxicity target

  16. Response of native insect communities to invasive plants.

    Science.gov (United States)

    Bezemer, T Martijn; Harvey, Jeffrey A; Cronin, James T

    2014-01-01

    Invasive plants can disrupt a range of trophic interactions in native communities. As a novel resource they can affect the performance of native insect herbivores and their natural enemies such as parasitoids and predators, and this can lead to host shifts of these herbivores and natural enemies. Through the release of volatile compounds, and by changing the chemical complexity of the habitat, invasive plants can also affect the behavior of native insects such as herbivores, parasitoids, and pollinators. Studies that compare insects on related native and invasive plants in invaded habitats show that the abundance of insect herbivores is often lower on invasive plants, but that damage levels are similar. The impact of invasive plants on the population dynamics of resident insect species has been rarely examined, but invasive plants can influence the spatial and temporal dynamics of native insect (meta)populations and communities, ultimately leading to changes at the landscape level.

  17. Coastal Freshwater Wetland Plant Community Response to Seasonal Drought and Flooding in Northwestern Costa Rica

    Science.gov (United States)

    In tropical wet-dry climates, seasonal hydrologic cycles drive wetland plant community change and produce distinct seasonal plant assemblages. In this study, we examined the plant community response to seasonal flooding and drought in a large coastal freshwater wetland in northwe...

  18. The molecular mechanism of zinc and cadmium stress response in plants

    NARCIS (Netherlands)

    Lin, Y.F.; Aarts, M.G.M.

    2012-01-01

    When plants are subjected to high metal exposure, different plant species take different strategies in response to metal-induced stress. Largely, plants can be distinguished in four groups: metal-sensitive species, metal-resistant excluder species, metal-tolerant non-hyperaccumulator species, and

  19. Plant-plant interactions mediate the plastic and genotypic response of Plantago asiatica to CO2 : an experiment with plant populations from naturally high CO2 areas

    NARCIS (Netherlands)

    van Loon, Marloes P; Rietkerk, Max; Dekker, Stefan C; Hikosaka, Kouki; Ueda, Miki U; Anten, Niels P R

    2016-01-01

    Background and Aims The rising atmospheric CO2 concentration ([CO2]) is a ubiquitous selective force that may strongly impact species distribution and vegetation functioning. Plant–plant interactions could mediate the trajectory of vegetation responses to elevated [CO2], because some plants may

  20. Are the metabolomic responses to folivory of closely related plant species linked to macroevolutionary and plant-folivore coevolutionary processes?

    Energy Technology Data Exchange (ETDEWEB)

    Rivas-Ubach, Albert [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland Washington 99354 USA; CREAF, Cerdanyola del Vallès 08913 Catalonia Spain; Hódar, José A. [Grupo de Ecología Terrestre, Departamento de Biología Animal y Ecología, Facultad de Ciencias, Universidad de Granada, 18071 Granada Spain; Sardans, Jordi [CREAF, Cerdanyola del Vallès 08913 Catalonia Spain; CSIC, Global Ecology Unit CREAF-CEAB-CSIC-UAB, Cerdanyola del Vallès 08913 Catalonia Spain; Kyle, Jennifer E. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland Washington 99354 USA; Kim, Young-Mo [Biological Sciences Division, Pacific Northwest National Laboratory, Richland Washington 99354 USA; Oravec, Michal [Global Change Research Centre, Academy of Sciences of the Czech Republic, Bĕlidla 4a CZ-603 00 Brno Czech Republic; Urban, Otmar [Global Change Research Centre, Academy of Sciences of the Czech Republic, Bĕlidla 4a CZ-603 00 Brno Czech Republic; Guenther, Alex [Department of Earth System Science, University of California, Irvine California 92697 USA; Peñuelas, Josep [CREAF, Cerdanyola del Vallès 08913 Catalonia Spain; CSIC, Global Ecology Unit CREAF-CEAB-CSIC-UAB, Cerdanyola del Vallès 08913 Catalonia Spain

    2016-06-02

    The debate whether the coevolution of plants and insects or macroevolutionary processes (phylogeny) is the main driver determining the arsenal of molecular defensive compounds of plants remains unresolved. Attacks by herbivorous insects affect not only the composition of defensive compounds in plants but the entire metabolome (the set of molecular metabolites), including defensive compounds. Metabolomes are the final products of genotypes and are directly affected by macroevolutionary processes, so closely related species should have similar metabolomic compositions and may respond in similar ways to attacks by folivores. We analyzed the elemental compositions and metabolomes of needles from Pinus pinaster, P. nigra and P. sylvestris to determine if these closely related Pinus species with different coevolutionary histories with the caterpillars of the processionary moth respond similarly to attacks by this lepidopteran. All pines had different metabolomes and metabolic responses to herbivorous attack. The metabolomic variation among the pine species and the responses to folivory reflected their macroevolutionary relationships, with P. pinaster having the most divergent metabolome. The concentrations of phenolic metabolites were generally not higher in the attacked trees, which had lower concentrations of terpenes, suggesting that herbivores avoid individuals with high concentrations of terpenes. Our results suggest that macroevolutionary history plays important roles in the metabolomic responses of these pine species to folivory, but plant-insect coevolution probably constrains those responses. Combinations of different evolutionary factors and trade-offs are likely responsible for the different responses of each species to folivory, which is not necessarily exclusively linked to plant-insect coevolution.

  1. The Exogenous Amelioration Roles of Growth Regulators on Crop Plants Grow under Different Osmotic Potential

    Directory of Open Access Journals (Sweden)

    Hamdia M. Abd El-Samad

    2014-03-01

    Full Text Available The production of fresh and dry matter of maize, wheat, cotton, broad and parsley plants show a variable response to the elevation of salinity stress. The production of fresh and dry matter of shoots and roots in wheat and broad bean plants tended to decrease with increasing NaCl concentration, salt stress progressively decrease in fresh and dry matter yield of maize plants. The increase in salinization levels induced a general insignificant change in production of fresh and dry matter of both organs of parsley plants. However, salinity induced a marked increase in the values of fresh and dry matter yields of cotton plants grown at the lowest level (-0.3 MPa NaCl and a reduction at higher salinization levels. Leaf area of unsprayed plants was excesivly decreased with the rise of osmotic stress levels especially at higher salinity levels of maize, wheat, cotton, and broad bean and parsley plants. the total pigments concentration decreased with rise of salinization levels in maize and cotton, these contents remained more or less un affected up to the level of 0.6 MPa NaCl in wheat and up to 0.9 MPa in parsley plants, there above, they were significantly reduced with increasing salinity levels. In broad bean plants the total pigments contents showed a non-significant alterations at all salinity stress. Spraying the vegetative parts of the five tested plants with 200 ppm of either GA3 or kinetin completely ameliorated the deleterious effect of salinity in fresh, dry matter, leaf area and pigment contents.

  2. 3D lidar imaging for detecting and understanding plant responses and canopy structure.

    Science.gov (United States)

    Omasa, Kenji; Hosoi, Fumiki; Konishi, Atsumi

    2007-01-01

    Understanding and diagnosing plant responses to stress will benefit greatly from three-dimensional (3D) measurement and analysis of plant properties because plant responses are strongly related to their 3D structures. Light detection and ranging (lidar) has recently emerged as a powerful tool for direct 3D measurement of plant structure. Here the use of 3D lidar imaging to estimate plant properties such as canopy height, canopy structure, carbon stock, and species is demonstrated, and plant growth and shape responses are assessed by reviewing the development of lidar systems and their applications from the leaf level to canopy remote sensing. In addition, the recent creation of accurate 3D lidar images combined with natural colour, chlorophyll fluorescence, photochemical reflectance index, and leaf temperature images is demonstrated, thereby providing information on responses of pigments, photosynthesis, transpiration, stomatal opening, and shape to environmental stresses; these data can be integrated with 3D images of the plants using computer graphics techniques. Future lidar applications that provide more accurate dynamic estimation of various plant properties should improve our understanding of plant responses to stress and of interactions between plants and their environment. Moreover, combining 3D lidar with other passive and active imaging techniques will potentia