Photosynthetic machinery and antioxidant status of wheat genotypes under drought stress followed by rewatering

Land plants shorten their vegetation period during water deficiency. Under water stress, wheat plants undergo several changes at the morphophysiological level. We tried to elucidate the role of the morphophysiological parameters and the photosynthetic machinery in response to drought followed by rewatering. Therefore, some morphophysiological traits of two bread wheat genotypes (drought-tolerant Gobustan, drought-sensitive Tale 38) were studied. The H2O2 content increased under drought in both genotypes but recovered in the Gobustan genotype after rewatering. The isozymes of peroxidase manifested dynamic changes under drought. The electron transport rate and the maximum photochemical quantum efficiency of PSII showed similar responses to drought with subsequent rewatering in both genotypes. However, the amount of the photosynthetic pigments changed drastically resulting in structural changes of thylakoid membranes. In Gobustan, the thylakoid membrane structure almost completely recovered after rewatering. Thus, the drought-tolerant genotype shows a more dynamic response of photosynthetic machinery and antioxidant capacity.