Biochemical Changes in Membrane Integrity and Osmoregulation in Wheat Genotypes under Water Stress

Four genotypes of bread-wheat (Triticum aestivum L.) i.e. Lok-1, Raj-3077, GW-273 and GW-322 were subjected to water stress that was imposed at the reproductive phase (viz., pre-anthesis, of 71 DAS and mid-anthesis, of 84 DAS periods) and physiologically assessed by flag leaf relative water contents and membrane stability indices which were found reduced in the stressed tissues. It is well known that an oxidative stress results due to water deficiency that triggers lipid peroxidation; the latter measured as accumulation of malondialdehyde. This also resulted in accumulation of osmolytes (viz., L-proline and water soluble sugars). The concentrations of these molecules were significantly enhanced in stressed flag-leaf tissues of all four wheat genotypes at 71 and 84 DAS periods, respectively. Results of the present study suggest that these low molecular weight metabolites could serve as useful biochemical markers for screening drought tolerance in wheat genotypes grown under arid to semi-arid conditions.