Deciphering plant responses to Salt stress: Growth inhibition, Chlorophyll degradation and Antioxidant imbalance
Shivani Singh1 , Aman Saket1 , Heena Choudhary1 , A. K. Shukla1 and T. Srinivasan
1Department of Botany, Indira Gandhi National Tribal University, Amarkantak - 484887 (India) 2Department of Botany, Central Tribal University Andhra Pradesh, Vizianagaram - 535003 (India)
ABSTRACT
Salinity is a key environmental stressor that adversely affects growth and development of plants. Effect of increasing NaCl concentrations (0-200mM) on germination, growth of plants, with a focus on antioxidant defense mechanisms has been investigated for rice plants. Significant declines in germination percentage, shoot length, and root length on increasing of salinity. Seed germination dropped from 92% in control plants to 40% at 200 mM concentration of NaCl. The quantities of chlorophyll-a and chlorophyll-b also dropped significantly indicating impaired photosynthetic capacity, while carotenoids exhibited resilience at moderate level of NaCl concentrations but declined at higher levels. Proline accumulation increased significantly with rising salinity. The study further shows that relative water content (RWC) declined as salt concentration increased, however malondialdehyde (MDA) levels increases indicating enhanced oxidative stress. Antioxidant enzyme analysis revealed that superoxide dismutase (SOD) activity rises with salinity, while catalase (CAT) activity decreased, highlighting an imbalance in the plant’s capacity to detoxify ROS. Investigations provides important insights into the physiological and biochemical responses of plants to salinity stress and suggests possible strategies for enhancing salt tolerance in rice through antioxidant defense.