Salicylic acid improves salinity tolerance in field pea (Pisum sativum L.) by intensifying antioxidant defense system and preventing salt-induced nitrate reductase (NR) activity loss

摘要

To improve the antioxidant system and protect the nitrate reductase (NR) activity of two field pea genotypes (DDR 61 and HUDP 15) by seed hardening through optimum concentration salicylic acid (SA) @ 1.0 mM under salinity stress condition. Salinity was imposed by NaCl @ 50,100 and 150 mM with their corresponding EC 4.0, 8.2 and 10.6 dSm(-1) respectively. Nitrate reductase (NR) activity significantly reduced under stress at the reproductive (i.e. post anthesis) stage but was maintained higher in 1.0 mM SA treated plants upto the level of 100 mM NaCl. In addition to NR, membrane stability index (MSI) also decreased significantly under salinity stress. In DDR 61 MSI was found to be more as compared to HUDP 15. On the other hand, activities of antioxidant enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT) were up-regulated by salinity stress and further enhanced remarkably by 1.0 mM SA treatment. DDR 61 genotype was found to be more responsive to SA application as compared to HUDP 15. Salt stress was found to have more damaging effects during the pre-anthesis phase than the post-anthesis phase of development. Hence, results signify the role of SA in protecting NR metabolic activity along with regulating salinity response of plants.