Salt stress in plants and amelioration strategies: alleviation of agriculture and livelihood risks after the Covid-19 pandemic

Agriculture sustains the livelihoods of over 2.5 billion people worldwide. The growing nature of disasters, the systemic nature of risk, a more recent pandemic along with abiotic stress factors are endangering our entire food system. In these stressful environment, it is widely reprimanded that strategies should be encompassed to attain increased crop yield and economic returns which would alleviate food and nutritional scarcity in developing countries. To study the physiological responses to salt stress, Vigna radiata seedlings subjected to varying levels of salt stress (0, 25, 50, 100 and 200 mM NaCl) were evaluated by tracking changes in Chl a fluorescence, pigment content, free proline and carotenoids content by HPLC. The ability of plants to adapt to salt stress is related with the plasticity and resilience of photosynthesis. As salt concentration increased, chlorophyll fluorescence indices decreased and a reduction in the PSII linear electron transport rate was observed. Chlorophyll fluorescence parameters can be used for in vitro non-invasive monitoring of plants responses to salt stress. Overall, Vigna responded to salt stress by the changes in avoidance mechanism and protective systems. Chl fluorescence indices, enzymatic contents of POD, CAT and free proline were sensitive to salt stress. The study is significant to evaluate the tolerance mechanisms of plants to salt stress and may develop insights for breeding new salt-tolerant varieties.