Modulation in Growth, Gas Exchange and Antioxidant Activities of Salt Stressed Rice (Oryza Sativa l.) Genotypes by Zinc Fertilization
Salt stress poses a major threat against rice that is reinforced by Zn deficiency especially in calcareous and alkaline soils due to high pH, calcareousness and climate of arid to semi arid. With the objective to ameliorate the salt stress through exogenous Zn application. There were four rice genotypes (BAS- 2000, KSK- 133, IR- 6 andBas-198) were subjected to two salinity levels (control and 70 mM) in the presence of two levels of zinc (control and 15.00 mgkg-1 ). Results revealed that salinity stress adversely affected the biochemical, morphological, physiological activities of all rice genotypes.The application of Zn significantly improved the crop performance both under saline and non-saline conditions. Studies further exhibited that KSK-133 found leading genotype at salt stressed conditions by showing less reduction in plant growth attributes i.e plant biomass, SPAD value, stomatal conductance, photosynthetic rate, transpiration rate, antioxidant enzymes i-e Superoxide dismutase (SOD) and Catalase (CAT) activities, Zn concentration and K+/Na+, relative to percent of control treatment. The results of our experiment clearly indicated that under salt stressed conditions KSK-133 performed well then BAS- 2000 and IR- 6while genotype Bas- 198 was observed sensitive against salinity stress. In case of non-saline conditions by Zn application, Basmati-2000 performed well compared to others.
Keywords - Salt Stress, Gas Exchange, Chlorophyll Contents, Antioxidant Enzymes, K+/Na+ Ratio