EFFECT OF EXOGENOUSLY APPLIED NITRIC OXIDE ON SOME KEY PHYSIOLOGICAL ATTRIBUTES OF RICE (ORYZA SATIVA L.) PLANTS UNDER SALT STRESS

Abstract

The aim of the present investigation was to assess the ameliorative effect of nitric oxide on some salt stressed rice (Oryza sativa L.) plants using some key physiological criteria. The experiment comprised four rice cultivars, two of them being fine (Shaheen Basmati & Basmati PB-95) and two coarse (KS-282 and IRRI-6) rice cultivars, two salt levels (0 and 80 mM of NaCl) and three nitric oxide levels (0, 0.1 and 0.2 mM). Salt stress caused a marked reduction in chlorophyll contents, photosynthetic rate, transpiration rate, stomatal conductance and intrinsic CO2 concentration of all four rice cultivars. Similarly, chlorophyll fluorescence attributes were also markedly altered due to imposition of NaCl stress. Presowing seed treatment with nitric oxide significantly improved chlorophyll content, and gas exchange and chlorophyll fluorescence attributes in salt-stressed and non-stressed plants of all four rice cultivars. Of rice cultivars, Shaheen basmati and IRRI-6 performed better than cvs. Basmati PB-95 and KS-282 in terms of the parameters measured in this study.