Abstract
Selenium (Se) is a trace element but its basic role in plant physiology is still poorly known. An experiment to investigate the role of Se in enhancing cotton growth and its efficiency in alleviating PEG-induced water stress and NaCl-induced salt stress under controlled conditions was conducted. The hydroponically grown cotton was supplied with selenium dioxide (SeO2) as a source of Se. The study included six treatments (control, 80 mM NaCl, 50 g/L PEG-6000, 10 mu M Se, Se + NaCl and Se + PEG). All treatments were grown hydroponically in frequently aerated Hogland's solution for 15 days. The experiment was repeated once again to validate the results. The results demonstrated that NaCl and PEG decreased cotton biomass, photosynthetic pigments and the essential macro-nutrients significantly. However, H2O2, OH and MDA over-accumulated, CAT, POD and PPO activities up-regulated and SOD activity down-regulated by stress treatments. Plant biomass, pigments content and ionic balance were improved by Se supplementation to the growth medium. Nonetheless, ROS accumulation, Na uptake and the activities of CAT, POD and PPO were retrieved. The current work suggests Se as a potent treatment to counteract the detrimental effects of water and salt stresses on growth and metabolic activity of cotton.