Involvement of Ureides in Nitrogen Fixation Inhibition in Soybean1

The sensitivity of N2 fixation to drought stress in soybean (Glycine max Merr.) has been shown to be associated with high ureide accumulation in the shoots, which has led to the hypothesis that N2 fixation during drought is decreased by a feedback mechanism. The ureide feedback hypothesis was tested directly by measuring the effect of 10 mm ureide applied by stem infusion or in the nutrient solution of hydroponically grown plants on acetylene reduction activity (ARA). An almost complete inhibition of ARA was observed within 4 to 7 d after treatment, accompanied by an increase in ureide concentration in the shoot but not in the nodules. The inhibition of ARA resulting from ureide treatments was dependent on the concentration of applied ureide. Urea also inhibited ARA but asparagine resulted in the greatest inhibition of nodule activity. Because ureides did not accumulate in the nodule upon ureide treatment, it was concluded that they were not directly inhibitory to the nodules but that their influence mediated through a derivative compound, with asparagine being a potential candidate. Ureide treatment resulted in a continual decrease in nodule permeability to O2 simultaneous with the inhibition of nitrogenase activity during a 5-d treatment period, although it was not clear whether the latter phenomenon was a consequence or a cause of the decrease in the nodule permeability to O2.

Expression Studies of the Zeaxanthin Epoxidase Gene in Nicotiana plumbaginifolia1

Abscisic acid (ABA) is a plant hormone involved in the control of a wide range of physiological processes, including adaptation to environmental stress and seed development. In higher plants ABA is a breakdown product of xanthophyll carotenoids (C40) via the C15 intermediate xanthoxin. The ABA2 gene of Nicotiana plumbaginifolia encodes zeaxanthin epoxidase, which catalyzes the conversion of zeaxanthin to violaxanthin. In this study we analyzed steady-state levels of ABA2 mRNA in N. plumbaginifolia. The ABA2 mRNA accumulated in all plant organs, but transcript levels were found to be higher in aerial parts (stems and leaves) than in roots and seeds. In leaves ABA2 mRNA accumulation displayed a day/night cycle; however, the ABA2 protein level remained constant. In roots no diurnal fluctuation in mRNA levels was observed. In seeds the ABA2 mRNA level peaked around the middle of development, when ABA content has been shown to increase in many species. In conditions of drought stress, ABA levels increased in both leaves and roots. A concomitant accumulation of ABA2 mRNA was observed in roots but not in leaves. These results are discussed in relation to the role of zeaxanthin epoxidase both in the xanthophyll cycle and in the synthesis of ABA precursors.

Ultraviolet-B Radiation Effects on Water Relations, Leaf Development, and Photosynthesis in Droughted Pea Plants1

The effects of ultraviolet-B (UV-B) radiation on water relations, leaf development, and gas-exchange characteristics in pea (Pisum sativum L. cv Meteor) plants subjected to drought were investigated. Plants grown throughout their development under a high irradiance of UV-B radiation (0.63 W m−2) were compared with those grown without UV-B radiation, and after 12 d one-half of the plants were subjected to 24 d of drought that resulted in mild water stress. UV-B radiation resulted in a decrease of adaxial stomatal conductance by approximately 65%, increasing stomatal limitation of CO2 uptake by 10 to 15%. However, there was no loss of mesophyll light-saturated photosynthetic activity. Growth in UV-B radiation resulted in large reductions of leaf area and plant biomass, which were associated with a decline in leaf cell numbers and cell division. UV-B radiation also inhibited epidermal cell expansion of the exposed surface of leaves. There was an interaction between UV-B radiation and drought treatments: UV-B radiation both delayed and reduced the severity of drought stress through reductions in plant water-loss rates, stomatal conductance, and leaf area.

Molecular and Enzymatic Characterization of Three Phosphoinositide-Specific Phospholipase C Isoforms from Potato1

Many cellular responses to stimulation of cell-surface receptors by extracellular signals are transmitted across the plasma membrane by hydrolysis of phosphatidylinositol-4,5-bisphosphate (PIP2), which is cleaved into diacylglycerol and inositol-1,4,5-tris-phosphate by phosphoinositide-specific phospholipase C (PI-PLC). We present structural, biochemical, and RNA expression data for three distinct PI-PLC isoforms, StPLC1, StPLC2, and StPLC3, which were cloned from a guard cell-enriched tissue preparation of potato (Solanum tuberosum) leaves. All three enzymes contain the catalytic X and Y domains, as well as C2-like domains also present in all PI-PLCs. Analysis of the reaction products obtained from PIP2 hydrolysis unequivocally identified these enzymes as genuine PI-PLC isoforms. Recombinant StPLCs showed an optimal PIP2-hydrolyzing activity at 10 μm Ca2+ and were inhibited by Al3+ in equimolar amounts. In contrast to PI-PLC activity in plant plasma membranes, however, recombinant enzymes could not be activated by Mg2+. All three stplc genes are expressed in various tissues of potato, including leaves, flowers, tubers, and roots, and are affected by drought stress in a gene-specific manner.

Avaliação dos impactos de políticas públicas de transferência de renda na qualidade de vida no semiárido nordestino face às mudanças climáticas

Introdução: Os impactos das alterações climáticas são e serão sentidos localmente, e irão variar de lugar para lugar. Nas regiões mais sensíveis à variabilidade climática, onde outros fatores e restrições afetam o desenvolvimento, a mudança climática terá um impacto significativamente maior. Uma da preocupações mais recentes da comunidade científica é que esses impactos negativos das alterações climáticas sobre a sociedade, saúde e o meio ambiente possa vir a restringir quaisquer ganhos realizados até o momento na melhora da qualidade de vida das populações, e em especial na região nordeste do Brasil. Neste contexto, as mudanças climáticas, bem como a variabilidade climática natural com seus extremos, podem vir a acentuar uma vulnerabilidade social já existente, fazendo com que a qualidade de vida das populações mais vulneráveis seja especialmente e desproporcionalmente afetada. Objetivo: Analisar como os impactos das políticas públicas de transferência de renda em especial o Programa Bolsa Família e a Aposentadoria Rural influênciam a qualidade de vida frente à variabilidade e mudanças climáticas de famílias pobres no nordeste brasileiro. Métodos: Fez-se uso de métodos qualitativos e quantitativos de coleta e análise de dados sobre as diferentes formas de pobreza e vulnerabilidade e a relação com a capacidade de adaptação à seca, e como isso afeta a percepção de qualidade de vida em famílias pobres rurais e urbanas em dois municípios do estado do Ceará (Parambu e Boa Viagem) sobre o estresse da seca. Realizou-se 221 entrevistas domiciliares (141 na zona rural e 80 na zona urbana). Complementarmente foram coletados dados qualitativos obtidos através de entrevistas semiestruturadas com informantes-chaves (gestores municipais e estaduais, chefes religiosos, presidentes de associações rurais e agentes de saúde). Os dados foram codificados e analisados com o auxílio do N-Vivo e do SPSS. Resultados: Os resultados foram separados e apresentados em formato de três manuscritos. Em geral, os resultados mostram que apesar dos programas de transferência de renda agirem positivamente na 16 melhora da qualidade de vida da famílias beneficiadas, durante o evento de seca as famílias não conseguem superar os fatores que as tornam vulneráveis, o que pode afetar sua percepção de bem-estar subjetivo. Ao mesmo tempo, devido às limitações e deficiências das intervenções políticas de intervenção de seca, as relações de dependência e clientelismo, característica da região, continuam a perpetuar. Conclusão: Os ganhos materiais na qualidade de vida, promovidos pelos programas sociais, como o Bolsa Família e a pensão rural, apesar de serem necessários, não são suficientes para promover uma transformação na vida dessas famílias

Grain yield components of pearl millet under optimum conditions can be used to identify germplasm with adaptation to and zones

There is evidence that high-tillering, small-panicled pearl millet landraces are better adapted to the severe, unpredictable drought stress of the and zones of NW India than are low-tillering, large-panicled modern varieties, which significantly outyield the landraces under favourable conditions. In this paper, we analyse the relationship of and zone adaptation with the expression, under optimum conditions, of yield components that determine either the potential sink size or the ability to realise this potential. The objective is to test whether selection under optimal conditions for yield components can identify germplasm with adaptation to and zones in NW India, as this could potentially improve the efficiency of pearl millet improvement programs targeting and zones. We use data from an evaluation of over 100 landraces from NW India, conducted for two seasons under both severely drought-stressed and favourable conditions in northwest and south India. Trial average grain yields ranged from 14 g m(-2) to 182 g m(-2). The landraces were grouped into clusters, based on their phenology and yield components as measured under well-watered conditions in south India. In environments without pre-flowering drought stress, tillering type had no effect on potential sink size, but low-tillering, large-panicled landraces yielded significantly more grain, as they were better able to realise their potential sink size. By contrast, in two low-yielding and zone environments which experienced pre-anthesis drought stress, low-fillering, large-panicled landraces yielded significantly less grain than high-tillering ones with comparable phenology, because of both a reduced potential sink size and a reduced ability to realise this potential. The results indicate that the high grain yield of low-tillering, large-panicled landraces under favourable conditions is due to improved partitioning, rather than resource capture. However, under severe stress with restricted assimilate supply, high-tillering, small-panicled landraces are better able to produce a reproductive sink than are large-panicled ones. Selection under optimum conditions for yield components representing a resource allocation pattern favouring high yield under severe drought stress, combined with a capability to increase grain yield if assimilates are available, was more effective than direct selection for grain yield in identifying germplasm adapted to and zones. Incorporating such selection in early generations of variety testing could reduce the reliance on random stress environments. This should improve the efficiency of millet breeding programs targeting and zones. (c) 2005 Elsevier B.V. All rights reserved.

Alterações morfofisiológicas e moleculares em resposta a estresses abióticos em mamona (Ricinus communis L.)

The use of fossil fuels has been considered one of reason for the increase of pollution in the atmosphere and it may be related to the climate changes. Then, the research of the new sources of fuels will be important. Considering this, the use of biodiesel has been considered not as bad as petrol. The castor bean (Ricinus communis L.) is an important oilseed, which belongs to Euphorbiaceae family, and the oil found in the seed has important characteristics for biodiesel. This plant is considered as “rustic” as it does not need so much water for its development and oil production. Due to this, this plant has been considered to be ideal in semi-arid regions, such as the Northeast of Brazil. The aim of his study is to better understand the responses to abiotic stresses (drought and salinity) from castor bean plants using morphological, physiological and molecular tools. In order to do this, the castor bean plants were subjected to salt stress (50, 100, 150 and 200 mM NaCl) in a controlled environment and drought stress (5, 10, 15 days and 10 days cyclic). After these treatments, these plants were subjected to different analyzes: a) the expansion and retention of water from leaves; b) anatomy using leaves and roots. Based on these results, we found that castor suffered decrease in leaf area with increase drought stress, however restricted water loss, probably by accumulation of compatible solutes in the leaves. The anatomy data showed modifications in the vascular system. These modifications observed suggested that castor bean plant may be resistant to stress as it was verified in 5 days of drought as well as in 100 mM NaCl. In both conditions, these plants were fine. Probably these plants keep some solutes in the cell and then maintain the cell tugor. The data obtained in this study gave a better idea how castor bean plant responds to abiotic stress conditions - drought and salt stress

Predicting Forest Responses to Changing Environmental Conditions

Forests change with changes in their environment based on the physiological responses of individual trees. These short-term reactions have cumulative impacts on long-term demographic performance. For a tree in a forest community, success depends on biomass growth to capture above- and belowground resources and reproductive output to establish future generations. Here we examine aspects of how forests respond to changes in moisture and light availability and how these responses are related to tree demography and physiology.

First we address the long-term pattern of tree decline before death and its connection with drought. Increasing drought stress and chronic morbidity could have pervasive impacts on forest composition in many regions. We use long-term, whole-stand inventory data from southeastern U.S. forests to show that trees exposed to drought experience multiyear declines in growth prior to mortality. Following a severe, multiyear drought, 72% of trees that did not recover their pre-drought growth rates died within 10 years. This pattern was mediated by local moisture availability. As an index of morbidity prior to death, we calculated the difference in cumulative growth after drought relative to surviving conspecifics. The strength of drought-induced morbidity varied among species and was correlated with species drought tolerance.

Next, we investigate differences among tree species in reproductive output relative to biomass growth with changes in light availability. Previous studies reach conflicting conclusions about the constraints on reproductive allocation relative to growth and how they vary through time, across species, and between environments. We test the hypothesis that canopy exposure to light, a critical resource, limits reproductive allocation by comparing long-term relationships between reproduction and growth for trees from 21 species in forests throughout the southeastern U.S. We found that species had divergent responses to light availability, with shade-intolerant species experiencing an alleviation of trade-offs between growth and reproduction at high light. Shade-tolerant species showed no changes in reproductive output across light environments.

Given that the above patterns depend on the maintenance of transpiration, we next developed an approach for predicting whole-tree water use from sap flux observations. Accurately scaling these observations to tree- or stand-levels requires accounting for variation in sap flux between wood types and with depth into the tree. We compared different models with sap flux data to test the hypotheses that radial sap flux profiles differ by wood type and tree size. We show that radial variation in sap flux is dependent on wood type but independent of tree size for a range of temperate trees. The best-fitting model predicted out-of-sample sap flux observations and independent estimates of sapwood area with small errors, suggesting robustness in new settings. We outline a method for predicting whole-tree water use with this model and include computer code for simple implementation in other studies.

Finally, we estimated tree water balances during drought with a statistical time-series analysis. Moisture limitation in forest stands comes predominantly from water use by the trees themselves, a drought-stand feedback. We show that drought impacts on tree fitness and forest composition can be predicted by tracking the moisture reservoir available to each tree in a mass balance. We apply this model to multiple seasonal droughts in a temperate forest with measurements of tree water use to demonstrate how species and size differences modulate moisture availability across landscapes. As trees deplete their soil moisture reservoir during droughts, a transpiration deficit develops, leading to reduced biomass growth and reproductive output.

This dissertation draws connections between the physiological condition of individual trees and their behavior in crowded, diverse, and continually-changing forest stands. The analyses take advantage of growing data sets on both the physiology and demography of trees as well as novel statistical techniques that allow us to link these observations to realistic quantitative models. The results can be used to scale up tree measurements to entire stands and address questions about the future composition of forests and the land’s balance of water and carbon.

Caracterização fisio-molecular de cultivares de feijão (Phaseolus vulgaris L.) em resposta à deficiência hídrica

The identification of genotypes for drought tolerance has a great importance in breeding programs. The aim of this study was to characterize genotypes of beans in response to drought tolerance in different reproductive stages through physiologic, agronomic and molecular analysis. The experiment was conducted in greenhouse, using a randomized block design with four replicates; 10 cultivars: ANFC 9, ANFP 110, BRS Esplendor, BRSMG Realce, IPR Siriri, IPR Tangará, IPR Tuiuiu, IPR Uirapuru, IAC Imperador and IAC Milênio under two conditions of irrigation: plants irrigated during their entire life cycle, and plants under irrigation suppression in the reproductive stage (R7) until 16% of field capacity, when the irrigation was restored. In the last four days of stress, the gas exchanges were analyzed, and in the last day of stress was analyzed the percentage of closed stomata in the abaxial surface of the leaves, collected in different times of the day (9h, 12h, 15h and 18h). Additionally, plant samples were collected for the following analysis: fresh and dry mass of leaves, stems and legumes, and proline content in leaves and roots. The plants were harvested at the physiological maturity and the yield components and grain yield were determined. In addition, in order to identify polymorphisms in the sequences of promoters and genes related to drought, seven pairs of primers were tested on the group of genotypes. The drought susceptibility indexes (ISS) ranged from 0.65 to 1.10 in the group of genotypes, which the lowest values observed were for IAC Imperador (0.65) and BRS Esplendor (0.87), indicating the ability of these two genotypes to maintain grain yield under water stress condition. All genotypes showed reduction in yield components under water stress. IAC Imperador (43.4%) and BRS Esplendor (60.6%) had the lowest reductions in productivity and kept about 50% of the stomata closed during all the different times evaluated at last day of irrigation suppression. IAC Imperador showed greater water use efficiency and CO2 assimilation rate under drought stress. IPR Tuiuiú, IPR Tangará and IAC Imperador had the highest proline concentrations in the roots. Under water stress condition, there was a strong positive correlation (0.696) between the percentage of stomata closed with the number of grains per plant (0.696) and the fresh mass of leaves (0.731), the maximum percentage of stomata closed 73.71% in water stress. The accumulation of proline in the root was the character that most contributed to the divergence between the genotypes under water deficit, but not always the genotypes that have accumulated more proline were the most tolerant. The polymorphisms in DNA of coding and promoting sequences of transcription factors studied in this experiment did not discriminate tolerant genotypes from the sensitive ones to water stress.

GENETIC VARIATION, LOCAL ADAPTATION AND POPULATION STRUCTURE IN NORTH AMERICAN RED OAK SPECIES, QUERCUS RUBRA L. AND Q. ELLIPSOIDALIS E. J. HILL

Forest trees, like oaks, rely on high levels of genetic variation to adapt to varying environmental conditions. Thus, genetic variation and its distribution are important for the long-term survival and adaptability of oak populations. Climate change is projected to lead to increased drought and fire events as well as a northward migration of tree species, including oaks. Additionally, decline in oak regeneration has become increasingly concerning since it may lead to decreased gene flow and increased inbreeding levels. This will in turn lead to lowered levels of genetic diversity, negatively affecting the growth and survival of populations. At the same time, populations at the species’ distribution edge, like those in this study, could possess important stores of genetic diversity and adaptive potential, while also being vulnerable to climatic or anthropogenic changes. A survey of the level and distribution of genetic variation and identification of potentially adaptive genes is needed since adaptive genetic variation is essential for their long-term survival. Oaks possess a remarkable characteristic in that they maintain their species identity and specific environmental adaptations despite their propensity to hybridize. Thus, in the face of interspecific gene flow, some areas of the genome remain differentiated due to selection. This characteristic allows the study of local environmental adaptation through genetic variation analyses. Furthermore, using genic markers with known putative functions makes it possible to link those differentiated markers to potential adaptive traits (e.g., flowering time, drought stress tolerance). Demographic processes like gene flow and genetic drift also play an important role in how genes (including adaptive genes) are maintained or spread. These processes are influenced by disturbances, both natural and anthropogenic. An examination of how genetic variation is geographically distributed can display how these genetic processes and geographical disturbances influence genetic variation patterns. For example, the spatial clustering of closely related trees could promote inbreeding with associated negative effects (inbreeding depression), if gene flow is limited. In turn this can have negative consequences for a species’ ability to adapt to changing environmental conditions. In contrast, interspecific hybridization may also allow the transfer of genes between species that increase their adaptive potential in a changing environment. I have studied the ecologically divergent, interfertile red oaks, Quercus rubra and Q. ellipsoidalis, to identify genes with potential roles in adaptation to abiotic stress through traits such as drought tolerance and flowering time, and to assess the level and distribution of genetic variation. I found evidence for moderate gene flow between the two species and low interspecific genetic differences at most genetic markers (Lind and Gailing 2013). However, the screening of genic markers with potential roles in phenology and drought tolerance led to the identification of a CONSTANS-like (COL) gene, a candidate gene for flowering time and growth. This marker, located in the coding region of the gene, was highly differentiated between the two species in multiple geographical areas, despite interspecific gene flow, and may play a role in reproductive isolation and adaptive divergence between the two species (Lind-Riehl et al. 2014). Since climate change could result in a northward migration of trees species like oaks, this gene could be important in maintaining species identity despite increased contact zones between species (e.g., increased gene flow). Finally I examined differences in spatial genetic structure (SGS) and genetic variation between species and populations subjected to different management strategies and natural disturbances. Diverse management activities combined with various natural disturbances as well as species specific life history traits influenced SGS patterns and inbreeding levels (Lind-Riehl and Gailing submitted).

Wheat adaptation to climate change in the Mediterranean Basin: retracing the past to predict the future

Wheat productivity is alarmingly threatened by climate change in the Mediterranean Basin, where it is mainly cultivated as a rainfed crop and where the latest climatic projections foresee a rise in temperatures and a reduction in precipitation, with important yield losses expected, being drought the main abiotic stress hampering wheat productivity. Assessing and quantifying the alterations in wheat life cycle caused by climate change is thus a key goal, as well as understating the underlying mechanisms of drought resistance. The first part of this thesis is focused on these main topics. A precise quantification of climate change effects on wheat in this area was performed through a case study, coupling phenological, meteorological and grain quality data before and after climate change. Then, accurate and detailed literature search was performed, reviewing the main controversies regarding the reliability of various functional traits to be used as breeding tools for improving wheat drought stress resistance. The second part of this thesis is focused in identifying interesting genetic material to improve wheat drought stress resistance in the Mediterranean Basin, analyzing drought response on a panel of tetraploid wheat accessions in vitro and in vivo as well as in open field trials, chosen in the attempt to represent as much as possible the biodiversity of tetraploid wheat. The third part of this thesis highlights differences in technological, nutritional and nutraceutical quality between modern cultivars and landraces, focusing on lipids, primary metabolites and bioactive compounds. In fact, wheat adaptation to climate change does not only mean to guarantee satisfactory yields in adverse conditions. It also means to provide millions of consumers with a diet-base food crop, with an improved nutraceutical and nutritional quality. Therefore, investigation and selection process for abiotic stress resistance and for improved quality has to go hand in hand.

Competition between drought-tolerant upland rice cultivars and weeds under water stress condition

The objective of this study was to evaluate the competitiveness of two cultivars of upland rice drought-tolerant, cultured in coexistence with weed S. verticillata, under conditions of absence and presence of water stress. The experiment was conducted in a greenhouse at the Experimental Station of the Universidade Federal de Tocantins, Gurupi-TO Campus. The experimental design was completely randomized in a factorial 2 x 2 x 4 with four replications. The treatments consisted of two rice cultivars under two water conditions and four densities. At 57 days after emergence, were evaluated in rice cultivars and weed S. verticillata leaf area, dry weight of roots and shoots and total concentration and depth of roots. Was also evaluated in rice cultivars, plant height and number of tillers. Water stress caused a reduction in leaf area, the concentration of roots and vegetative components of dry matter (APDM, and MSR MST) of rice cultivars and Jatoba Catetão and weed S. verticillata. The competition established by the presence of the weed provided reduction of all vegetative components (MSPA, and MSR MST) of cultivars and Jatoba Catetão. It also decreased the number of tillers, the concentration of roots and leaf area. At the highest level of weed competition with rice cultivars, a greater decrease in vegetative components and leaf area of culture, regardless of water conditions.

Modelling predicts that heat stress, not drought, will increase vulnerability of wheat in Europe

New crop cultivars will be required for a changing climate characterised by increased summer drought and heat stress in Europe. However, the uncertainty in climate predictions poses a challenge to crop scientists and breeders who have limited time and resources and must select the most appropriate traits for improvement. Modelling is a powerful tool to quantify future threats to crops and hence identify targets for improvement. We have used a wheat simulation model combined with local-scale climate scenarios to predict impacts of heat stress and drought on winter wheat in Europe. Despite the lower summer precipitation projected for 2050s across Europe, relative yield losses from drought is predicted to be smaller in the future, because wheat will mature earlier avoiding severe drought. By contrast, the risk of heat stress around flowering will increase, potentially resulting in substantial yield losses for heat sensitive cultivars commonly grown in northern Europe.

Assessment of wheat cultivars for drought tolerance via osmotic stress imposed at early seedling growth stages

A study was conducted in the Department of Plant Breeding and Genetics,Sindh Agriculture University, Tandojam, Pakistan during the year 2009. Sixteen spring wheat cultivars (Triticum aestivum L.) were screened under osmotic stress with three treatments i.e. control-no PEG (polyethylene glycol), 15 percent and 25 percent PEG-6000 solution. The analysis of variance indicated significant differences among treatments for all seedling traits except seed germination percentage. Varieties also differed significantly in germination percentage, coleoptile length, shoot root length, shoot weight, root/shoot ratio and seed vigour index. However, shoot and root weights were non-significant. Significant interactions revealed that cultivars responded variably to osmotic stress treatments; hence provided better opportunity to select drought tolerant cultivars at seedling growth stages. The relative decrease over averages due to osmotic stress was 0.8 percent in seed germination, 53 percent in coleoptile length 62.9 percent in shoot length, 74.4 percent in root length, 50.6 percent in shoot weight, 45.1 percent in root weight, 30.2 percent in root/shoot ratio and 68.5 percent in seed vigour index. However, relative decrease of individual variety for various seedling traits could be more meaningful which indicated that cultivar TD-1 showed no reduction in coleoptile length, while minimum decline was noted in Anmol. For shoot length, cultivar Sarsabz expressed minimum reduction followed by Anmol. However, cultivars Anmol, Moomal, Inqalab-91, and Pavan gave almost equally lower reductions for root length suggesting their higher stress tolerance. In other words, cultivars Anmol, Moomal, Inqalab-91, Sarsabz, TD-1, ZA-77 and Pavan had relatively longer coleoptiles, shoots and roots, and were regarded as drought tolerant. Correlation coefficients among seedlings traits were significant and positive for all traits except germination percentage which had no significant correlation with any of other trait. The results indicated that increase in one trait may cause simultaneous increase in other traits; hence selection for any of these seedling attributes will lead to develop drought tolerant wheat cultivars.

An Arabidopsis Mitochondrial Uncoupling Protein Confers Tolerance to Drought and Salt Stress in Transgenic Tobacco Plants

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)