Effects of Sodium Nitroprusside and Amino Acid Arginine on Chilling Resistance in Tomato Plant

Cold stress is a major environmental factor affecting agricultural productivity of crops. Recent advances have revealed key components of stress signal transduction pathways that enhanced stress tolerance in plants. Considering nitric oxide (NO) is a ubiquitous bioactive molecule that plays a central role as a signal in plant responses to biotic and abiotic stress. In this research the effects of sodium nitroprusside (SNP) (as a NO releasing compound) and arginine (Arg) (as NOS substrate) pretreatment on alleviation of chilling stress were investigated and compared in tomato plant. In this study 3-week-old plants pretreated with SNP 100μM and arginine 5μM for 10 days and then subjected to 5°C for 6 h. Finally lipid peroxidation, Hydrogen peroxide content and activity of CAT, APX and GPX enzymes were investigated. Results showed that, SNP and Arg pretreatment declined the lipid peroxidation and hydrogen peroxide content. In addition the activity of GPX and APX increased in plants which were pretreated with SNP and Arg while CAT activity increased only in Arg pretreatment. It seems that Arg as a NO precursor, to produce other products such as polyamines and proline had a more effective role than SNP pretreatment.