Salicylic Acid as a Mitigating Agent of Salinity: Response of Kale cv. Tatsoi Shanghai in Salinized Semihydroponic Culture

In semiarid regions, water salinity is one of the main factors limiting the growth, yield and quality of leafy vegetables such as kale. In order to reduce the negative effects of salts on plants, studies have been carried out using growth regulators, such as salicylic acid, which is a promising strategy under stress conditions. The aim of this study was to evaluate the effect of salicylic acid on the growth and quality of kale cv. Tatsoi Shanghai under salt stress in semihydroponic cultivation. The treatments were distributed in a completely randomized design, in a 4 × 3 factorial scheme, referring to four salinity solutions (0.5, 1.5, 2.5, and 3.5 dS m^–1) and three concentrations of salicylic acid (0, 1, and 2 mM) applied via foliar. The variables analyzed were growth, biomass, indices chlorophylls and postharvest quality. The results showed that the application of 1 mM SA under moderate salinity (1.5 dS m^–1) resulted in greater plant height, number of leaves and chlorophyll indices. However, the application of 2 mM SA at high salinity (3.5 dS m^–1) reduced the total dry mass by 24.97% and the Hue angle by 10.14%, affecting visual quality. Without the application of SA, at high salinity, there was an increase of 17.57% in total dry biomass and 28.87% in leaf area, but with a reduction in the intensity of the green color. Based on the results, it was concluded that the effectiveness of SA depends on the concentration used and the level of salinity, with a concentration of 1 mM being the most suitable for mitigating the effects of moderate salt stress on kale cv. Tatsoi Shanghai.