Morpho-physiological and biochemical evaluation of two indica rice (Oryza sativa L) cultivars under abiotic stresses at the seedling stage

Abstract

Rice provides staple food for a large part of the world’s human population. Abiotic stresses, such as salinity, heat and low temperature stimulates diverse morphological, physiological and biochemical responses that negatively impact the plant growth, development and productivity of crops. Screening of rice genotypes against abiotic stress is a fundamental step to understand the mechanism and stress tolerance of rice cultivars. Two indica rice cv Nagina22 (N22) and Pusa Sugandh2 (PS2) were screened for salt (150mM NaCl), cold (12°C) and heat (40°C) stress responses through morpho-physiological and biochemical traits at the seedling stage. FL478 and MTU1010 varieties were used as salt and cold tolerant control, respectively. The present investigation showed salinity and cold tolerance of PS2 was noticeable through lower reduction in fresh and dry weight of seedlings, photosynthetic pigments and associated with higher accumulation of proline, lower ion leakage and MDA content under salinity and cold stresses. In contrast, under high temperature treatment, PS2 genotype had significantly higher reduction of biomass and photosynthetic pigments, less cell membrane stability, higher lipid peroxidation, and lower proline accumulation as compared to N22. From our study, PS2 was found to be tolerant to cold and salinity stress, while N22 was found to be tolerant to heat stress. Evaluation of abiotic stress tolerance at seedling stage against salt, cold and heat stresses by utilizing morphological, physiological and biochemical approaches is an appropriate way in rice, when used along with suitable check variety.