Physiological mechanisms of adaptation of alloplasmic wheat hybrids to soil drought

We studied physiological mechanisms of plant adaptation to drought for two alloplasmic wheat (Triticum aestivum L.) hybrids (APHs) on the cytoplasm of rye (Secale cereale L.) or ovate goatgrass (Aegilops ovata L.) and two standard regionalized spring wheat cultivars, Kometa and Priokskaya. In response to plant tissue dehydration, APHs rapidly reduced the transpiration rate and lost much less water than standard cultivars. During drought, peroxidase activity was significantly increased only in APH on the rye cytoplasm, whereas it declined substantially in cv. Kometa. Peroxidation of lipids (POL) was activated in cv. Kometa stronger than in hybrids, which also indicates that, in this cultivar, there was no complete detoxification of hydrogen peroxide under stress conditions. After watering resumption, APHs displayed a better capacity for reparation than standard cultivars, which was manifested in peroxidase activation and POL suppression, i.e., in more complete reduction of the oxidative stress consequences. We concluded that a higher APH drought resistance, as compared with standard cultivars, was determined by their more efficient antioxidant defense and a better capacity for recovery. © 2007 Pleiades Publishing, Ltd.