PSII photochemistry, oxidative damage and anti-oxidative enzymes in arsenate-stressed Oryza sativa L. seedlings

Abstract

ABSTRACTThe aim of the present study was to quantify the arsenic-induced damage in rice seedlings in terms of certain physiological and biochemical parameters. For this, hydroponically grown Oryza sativa L. seedlings were exposed to certain doses of AsV as Na2HAsO4 (10, 25, 50 and 100 µM). All the tested doses manifested in a significant loss in the pigments content and photosynthesis, which culminated in retarded growth of the seedlings. The AsV-mediated decline in PSII photochemistry could be correlated with the decline in ϕP0, ψ0, ϕE0 and PIABS. In vitro and in vivo detection of and H2O2 and the consequent rise in malondialdehyde equivalents after AsV treatments stimulated the anti-oxidant enzymes, that is, superoxide dismutase (SOD) (except at 50 and 100 µM AsV), peroxidase and catalase, activity which was further confirmed by the native polyacrylamide gel electrophoresis (PAGE) that also revealed the least expression of SOD isoforms against 50 and 100 µM AsV treatment. The present investigation is a categorical demonstration of the inhibitory behaviour of AsV in O. sativa L. seedlings. At lower doses of arsenate, reactive oxygen species and anti-oxidants cooperatively acted in such a way that the impacts of the stress were far lesser on various growth and physiological parameters.