Interaction effects of nitric oxideand salicylic acid in alleviating salt stress of Gossypium hirsutum L.

Abstract

The effects of sodium nitroprusside (SNP, a nitric oxide donor), salicylic acid (SA), and their combination on some physiological parameters of cotton (Gossypium hirsutum L.) seedlings grown under saline conditions were studied. 100 mM NaCl resulted in a decrease in photosynthetic attributes and chlorophyll content, and induced an increase in the level of electrolyte leakage, malondialdehyde (MDA) content, O2•- generation rate, H2O2 and proline contents. 0.1 mM SNP decreased Na+ and Cl- accumulation as well as the lipid peroxidation level and O2•- accumulation in leaves, which contributed to alleviate oxidative stress in cotton leaves. 0.1 mM SA alleviated the oxidative stress by increasing K+ and Mg2+ absorption and osmotic regulators accumulation, and decreasing the H2O2 content. However, the protective action of NO and SA (especially 0.05 mM SNP and 0.05 mM SA) against salt-induced oxidative damage was more efficient than the separate effects of SA and SNP.We observed that the accumulation of osmotic regulators was apparently accelerated by 0.05 mM SNP and 0.05 mM SA. As well, it was observed that they had synergistic effects in antioxidant system and ion absorption. Thus, the combination of SNP and SA can be a new indicator of a protective mechanism to lower lipid peroxidation, improve ion absorption, activate the metabolic of osmotic-regulated substances and facilitate the membrane transport to detoxify reactive oxygen species (ROS).