The effect of various concentrations salicylic acid on mitigation of sodium chloride stress in growth parameters and photosynthetic pigments of sunflower plant (Helianthus annuus L.)

Soil salinity is a serious environmental problem that has negative effect on plants’ growth and production. On the other hand, salicylic acid plays an essential role in preventing oxidative damage in plants by detoxifying superoxide radicals produced as a result of salinity. In this research the effect of different concentrations of salicylic acid, sodium chloride, and interaction effects of both factors were studied on morphological and biochemical parameters in sunflower (Helianthus annuus L.) plants. NaCl concentrations of 0, 25, 50, 75, and 100 mM and salicylic acid concentrations of 0, 0.5, 1, and 1.5 mM were used in the form of a factorial experiment in a complete randomized design (CRD). Results showed that salinity caused significant decrease in shoot and root length, fresh and dry weights, chlorophylls, and carotenoid of plants while in salicylic acid pre-treated plants, this reduction has been moderated. On the other hand, increasing the amount of anthocyanin, chlorophylls, and carotenoid indicated the role of salicylic acid in increasing the tolerance of this plant to sodium chloride stress. These findings suggest that salicylic acid application increases plant tolerance to sodium chloride stress.