Physiological and biochemical responses of Moringa oleifera seed sources in subtropical climate

To cope with fluctuating seasonal weather conditions in subtropical climate, trees showed varying levels of physiological responses that aren’t well known in Moringa oleifera which is being considered as nutritional dynamite after covid-19 pandemic. The work aimed at exploring the adaptability of eighteen geographically diverse seed sources of M. oleifera by measuring physiological and biochemical responses over varying levels of leaf maturity. In relation to our hypothesis, significantly (p < 0.01) higher values of RWC, MSI, TSP, TSS, Chlorophyll, TPC, carotenoids and ascorbic acid are found during the winter compared to summer except peroxidase and SOD activities. Very high temperature (~ 35.6^OC) during day-time caused decreases physiological activities in summer compared to values obtained in winter season; however, enzymatic activities were higher in summer indicating stressed conditions. Mature leaves had maximum RWC, MSI, TSP, Chl-b, TPC, Peroxidase &, SOD activities, carotenoids and ascorbic acid than tender leaves except TSS. However, tender leaves showed higher value of Chl-a in winter season and mature had in summer season due to which, total chlorophyll content followed the same pattern. Thus, physiological responses except TSS increased as leaf matured. The significant positive correlations were observed for all physiological traits except PEA and SOD. However, PEA showed positive correlation with SOD, and ascorbic acid showed negative correlation with SOD and PEA. Thus, the source S9 for PEA; S7 for SOD; S15 for proteins; S2 for sugars; S8 for carotenoids in and S7 for ascorbic acid (vitamin-C) recorded noteworthy performance during study due to somewhat expressive physiological performance. Hence, tropical seed sources are well adapted in subtropical climatic conditions than semi-arid and arid seed sources and could be lyophilized to produce natural food supplements by adopting the suitable maturity stage for harvesting of leaves to hike up the human immune health by meeting their nutritional requirements.