Salicylic acid attenuates the harmful effects of salt stress on basil

ABSTRACT The salinity of irrigation water and soil create considerable challenges in agriculture, as they harm the physiological processes and growth of plants. The exogenous application of antioxidant compounds, such as salicylic acid, can reduce the damage caused by salt stress. Thus, this study aimed to evaluate the attenuation of salt stress induced by salicylic acid in Ocimum basilicum “Cinnamon”. The experiment was performed in randomized blocks with five irrigation water salinity levels (0.5, 1.3, 3.25, 5.2 and 6.0 dS m-1) and five salicylic acid concentrations (0, 0.29, 1.0, 1.71 and 2.0 mM), with five repetitions and two plants per plot. Growth, gas exchange, and chlorophyll indices and fluorescence were evaluated 30 days after the salt treatment was applied. An increase in the salinity of irrigation water decreased the plant height, stem diameter, number of leaves, stomatal conductance, instantaneous water use efficiency, and initial fluorescence of basil “Cinnamon”. Salicylic acid was revealed to attenuate the harmful effects of irrigation water salinity on gas exchange, total chlorophyll, and initial and maximum fluorescence of basil plants.