Exogenous salicylic acid-induced nitric oxide regulates leaf water condition through root osmoregulation of maize seedlings under drought stress

Under drought stress, the role of nitric oxide (NO) in the regulation of leaf water condition by salicylic acid (SA) through root osmoregulation of maize (Zea mays L.) seedlings was investigated. The results showed that drought stress markedly increased the contents of NO, soluble sugar, proline, soluble protein, Na+, K+ and Ca2+, as well as the activity of plasmalemma H+-ATPase in roots, compared with control. However, drought stress significantly decreased root hydraulic conductivity and leaf relative water content (RWC). Exogenous SA under drought stress significantly increased above indicators, compared with drought stress alone. Above effects of SA were significantly inhibited by the pretreatment with NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO). Overall, the findings indicated that SA-induced NO participated in the regulation of leaf water condition through root osmoregulation of maize seedlings under drought stress.