Exogenous application of nitric oxide and thiourea regulates on growth and some key physiological processes in maize (Zea mays L.) plants under saline stress.

Abstract

Effect of exogenously applied nitric oxide (NO) and thiourea (TU) in combination was examined inmaize plants under saline stress. Seedlings of two maize cultivars (DK 5783 and Apex 836) were grownin pots containing soil salinized with 0 or 100 mM NaCl dissolved in irrigation water. Two levels of NO+ TU (3 + 400 or 6 + 500 mg/L) were applied as presowing seed treatment or through leaves of 10-dayold maize seedlings. Saline stress significantly suppressed plant fresh biomass, leaf water potential andchlorophyll content, but increased electrolyte leakage in both cultivars. However, these reductions werehigher in Apex 836 than those in Dk 5783. Both treatments of combined NO and TU as seed soakingor foliar application were effective in mitigating the adverse effects of saline stress on shoot growth. Seedtreatments of both levels of combined NO and TU were more effective in terms of improvement in freshweights of DK 5783 than foliar treatments. Leaf Na+ contents increased whereas those of N and Pdecreased in maize plants under saline regime. Application of Both modes of treatment of combinedNO and TU increased the contents of N and P, but decreased that NO and TU through both modesincreased Na+ in salt stressed maize plants. The results of the present study indicate that application ofNO and TU compounds in combination alleviated the detrimental effects of salinity and increasedresistance to salinity in the maize plants by improving plant growth