Effects of non-uniform salt stress on growth, yield, and quality of tomato

Abstract

Previous studies found that non-uniform salt stress could alleviate salt damage to plants compared to uniform salt treatment. The root system of tomato was divided into two parts, including salt-free treatment (NaCl concentrations were zero in both root systems), non-uniform salt stress with a NaCl concentration of 0.1% in one side of the roots (0.1%, 0.3%; 0.1%, 0.5%), non-uniform salt stress with a NaCl concentration of 0.2% in one side of the roots (0.2%, 0.4%), and uniform salt stress (0.2%, 0.2%; 0.3%, 0.3%) treatments. Compared with uniform stress, Na+ content in leaves decreased significantly (P < 0.05). The photosynthetic capacity of plants was significantly improved under the conditions of non-uniform salt treatment, which was mainly reflected in photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate (Tr). Under mild salt stress, the stem and leaf weight of T13 in the non-uniform salt treatment increased by 7.60%, the yield per plant increased by 2.35%, and the total soluble sugar content increased by 6.85% compared with the uniform salt treatment T22. Under moderate salt stress, the stem and leaf weights of T15 and T24 in the non-uniform salt treatment increased by 14.62% and 5.77% compared with the uniform salt treatment T33, the yield per plant increased 6.04% and 3.49%, and the total soluble sugar content increased 18.94% and 7.97%. The study on the response of tomato under non-uniform saltinity was an important supplement to plant physiology under uniform saltinity, so as to provide references for cultivation and management in salt fields.