Alleviation of Salt Stress with Chitosan Foliar Application and Its Effects on Growth and Development in Tomato (Solanum lycopersicum L.)

Environmental and climatic fluctuations as well as abiotic stress factors affect agricultural production and cause a loss in quality and yield. It is important to find alternative solutions for the sustainability of agricultural production to feed the increasing population. Salt stress is one of the most devastating abiotic stress factors and tomato production is also affected by salt stress since it needs extensive irrigation for high yield. The exogenous application of some plant inducers showed promising results in the induction and improvement of plant tolerance to stress factors. Chitosan (2-amino-2-deoxy-b-D-glucosamine), one of the organic compounds, is getting significant attention in agriculture with its potential. Here, we evaluated the potential of chitosan application for salt stress tolerance on tomato. 0.03% and 0.05% chitosan solutions were applied as a foliar spray to the plant and salt tolerance improvement were investigated under untreated (0 mM NaCl) and 100 mM NaCl conditions. The growth-related (root and shoot diameters, above and below-ground biomass, number of leaves and branches, and plant height), photosynthetic parameters (chlorophyll a, b, total carotenoid content), and ion leakage were investigated. According to the results, chitosan application improves plant development in both untreated and salt-stress conditions and improved plant growth. Also, photosynthetic parameters showed that the application of chitosan increased chlorophyll contents under untreated conditions. Our result suggests that the application of chitosan may have a promising effect on salt stress tolerance and further research may shed light on its molecular mechanisms.