Moropho-physiological and biochemical responses of rice (Oryza sativa L.) to saline stress.

Abstract

Salinization is one of the environmental factorthat limits growth as well as yield of rice plants. Under stress tolerance plants change their growth along with various physiological and biochemical change. These changesresulted as activated signaling cascade and metabolic pathways. In this study, phospholipase C (PLC) inhibitors i.e. Neomycin(control and 100 µM) and U-73122 (Ethanol and 100 µM) were used as foliar applicationon rice (Bas-385, Bas-2000, Bas-370 and Shaheen) in saline conditions(control, 50, 100 and 150 mM NaCl). The trials were conducted in complete randomize design using four replications. Data for range of attributeshas been determined at vegetative and reproductive growth stage.Sodium chloridedecreased growth, water and osmotic potential, gas exchange characteristics, total soluble proteins and yield attributes while it increased chlorophyll a and b content, chlorophyll fluorescence, shoot root sodium, potassium, calcium ions, malondialdehyde (MDA), hydrogen peroxide (H2O2), glycinebetaine (GB) leaf free proline, activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in both experiments. Foliar application of neomycin decreased shoot fresh weight, chlorophyll a, b, Fv/Fm, stomatal conductance (gs), water and osmotic potential, root potassium, shoot calcium, MDA, H2O2, proteins while it increased shoot length, electron transport rate (ETR), non-photochemical quenching (NPQ), co-efficient of non-photochemical quenching (qN), photosynthetic rate (A), transpiration rate (E), shoot sodium, potassium, GB, free proline, total phenolics, ascorbic acid, SOD, POD, CAT, total number fertile tillers. Foliar applied U-73122 increased growth, chlorophyll a contents, qN, E, turgor pressure and sodium, potassium and calcium level, H2O2, total phenolics, ascorbic acid, grain number and 100 grains weight.It decreased chlorophyll b, A, water use efficiency (A/E), water and osmotic potential, chlorophyll fluorescence, free proline, MDA, proteins, SOD and POD activity and root calcium ion accumulation. Of all rice cultivars in the first experiment cv. Bas-2000 proved to be best in growth and yield attributes. In the second experiment cv. Bas-370 showed better results for growth, water relations and enzymatic antioxidant at both growth stages.