Effect of seed priming with L-arginine and sodium nitroprusside on some physiological parameters and antioxidant enzymes of sunflower plants exposed to salt stress.

Abstract

Salinity is one of the most important environmental stress factors limiting plant growth and productivity in differ regions. Previously sodium nitroprusside (SNP) was applied as a nitric oxide (NO) donor to counteract the effect of salt stress while there is little information about exogenous arginine application as a precursor of NO in the possible anti-oxidative responses of plants against salinity. In this research the effects of seed priming with SNP and L-arginine (Arg) on alleviation of oxidative damages caused by salinity (150 mM NaCl) were investigated in sunflower plants. The experiments were performed in a completely randomized design with 3 replicates. Our findings showed that salinity stress has negative effects on growth parameters, and application of Arg and SNP could alleviate the harmful effects of salinity. Results showed that in salt stressed plants, activity of lipoxygenase in root and leave tissues increased while, antioxidative enzymes activity decreased when compared with control. Application of SNP increased the activity of catalase (CAT), guaiacol peroxidase (GPX) and ascorbate peroxidase (APX) enzymes in root and leaves of plants while Arg pretreatment could only increase the activity of CAT and APX in root and leaves of plant, when compared with untreated plants. In this research, the effect of SNP and Arg on most studied parameters, were the same so we assumed that the effects of Arg may related to the NO releasing from Arg directly or indirectly and we propose the application of Arg as a new compound which can be used instead of SNP.