GrainGenes Reference Report: FPB-31-1149
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| | Physiological and morphological responses to water stress in Aegilops biuncialis and Triticum aestivum genotypes with differing tolerance to drought |
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| | The physiological and morphological responses to water stress induced by polyethylene glycol (PEG) or by withholding water were investigated in A. biuncialis genotypes (Ae1050, Ae 550 and Ae225) differing in the annual rainfall of their habitat (1050, 550 and 225 mm/year) and in wheat genotypes (MV9kr1, Sakha and Capelle Desprez) differing in drought tolerance. A decrease in the osmotic pressure of the nutrient solution from -0.027 to -1.8 MPa resulted in significant water loss, a low degree of stomatal closure and a decrease in the intercellular CO SUB 2 concentration ( C SUB i ) in Aegilops genotypes originating from dry habitats, while in wheat genotypes, high osmotic stress increased stomatal closure, resulting in a low level of water loss and high C SUB i . Nevertheless, under saturating light at normal atmospheric CO SUB 2 levels, the rate of CO SUB 2 assimilation was higher in Aegilops accessions under high osmotic stress compared to wheat genotypes. Moreover, in the wheat genotypes, CO SUB 2 assimilation exhibited less or no O SUB 2 sensitivity. These physiological responses were manifested in changes in the growth rate and biomass production, since Aegilops (Ae550 and Ae225) genotypes retained a higher growth rate (especially in the roots), biomass production and yield after drought stress than wheat. These results indicate that Aegilops genotypes, originating from a dry habitat have better drought tolerance than wheat, making them good candidates for improving the drought tolerance of wheat through intergeneric crossing |
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