Enhancing Salt Tolerance in Leafy Vegetables Using Microalgal Exopolysaccharides
摘要
Rapid population growth is intensifying food and water demand, straining agriculture and increasing salinity, threatening productivity. In this regard, microalgal EPS or exopolysaccharides shows potential as a plant bio-stimulant to mitigate these challenges. Against this backdrop, the present study aims to evaluate the potential of Spirulina-derived EPS in alleviating the effects of salt stress on hydroponically grown basil and spinach, subjected to 0 mM, 80 mM, and 160 mM NaCl for five weeks. After 35 days, the growth and biochemical parameters of the plants treated with microalgal EPS were compared to untreated counterparts. Under 80 mM salinity stress, treated basil and spinach showed 30 and 21% higher biomass productivity, respectively compared to their untreated counterpart. Upon increasing the saline stress to 160 mM, EPS treatment boosted basil productivity by 26%, though it was still 34% lower than the control group (unstressed plants). At 160 mM salinity, EPS treatment increased. For spinach, EPS treatment under same saline stress resulted in a 1.4-fold productivity increase, although still 18% lower than the control group. Further analysis revealed increased proline, total phenolic, and soluble sugar levels in treated plants under salt stress, along with a positive influence on the K+/Na+ ratio, suggesting the role of EPS in inducing plants’ stress-coping mechanism. Overall, the study reveals that the application of microalgal EPS can mitigate salt stress in leafy vegetables. This approach can be taken to enhance plant growth and productivity while combatting the dual challenges of water scarcity and salinity stress in agriculture in a sustainable manner.