Abstract

Water stress induced changes in antioxidant enzymes membrane stablity index and seed protein profiling of four different wheat (Triticum aestivum L.) accessions (011251, 011417, 011320 and 011393) were determined in a pot study under natural condition during the wheat-growing season 2005 and 2006. Sampling was done 3, 6 and 9 days after induction of water stress. Recovery was studied at 48 and 72 h of re-watering. Marked increase in leaf antioxidant enzymes associated with a decrease in membrane stability index occurred under water stress. Accession 320 showed the least increase in catalase and peroxidase activity but maximum decrease in membrane stability index. The inhibitory effects of water stress on plants were ameliorated by exogenous application of ABA and this ameliorating effect was found to be more significant at booting stage as compared to grainfilling particularly in the accession 320. The accessions 417 and 320 (which were most dissimilar on the basis of physiology under water stress, one most tolerant and the other most sensitive to water stress) showed least polymorphism among the four accessions on the basis of RAPD (Random Amplified Polymorphic DNA) analysis. Seed protein composition was found to be mainly controlled by genetic factors rather than water stress.

Key words: Grainfilling, booting, protein, antioxidants, wheat.