Effects of Exogenous Nitric Oxide on the Physiological and Biochemical Characteristics in Elaeagnus mollis Seedlings Under Water Stress

Effects of different levels of NO donor(sodium nitroprusside,SNP) pretreatments and PEG-6000 treatment on the leaf relative water content,chlorophyll content,net photosynthesis rate,lipid peroxidation and cell protective enzyme activity in Elaeagnus mollis seedling leaves under water stress were studied.The results showed that exogenous NO had a remarkable positive effect on leaf relative water content and could increase chlorophyll content.Lower concentrations of NO(0.1,0.2,0.4 and 0.6 mmol·L-1 SNP) could increase photosynthesis rate,but hihger concentrations of NO(0.8 and 1.0 mmol·L-1 SNP) had adverse effects.Exogenous NO could decrease MDA content and relative leakage ratio.With the increase of SNP level,POD activity in leaves showed an increasing trend,while CAT activity first increased and then decreased,and higher than CAT activity of the control.It is obvious that exogenous NO could retard the accumulation of active oxygen through inducing POD and CAT activities of leaves,alleviate the hurt of water stress to E.mollis seedlings,and increase its drought-resistant capacity.