Possible Reduction of the Effect of Salinity on Bean (Phaseolus vulgaris) with Application of Salicylic Acid

Salinity is the most important environmental stress that reduces plants growth and yield. It has been shown that salicylic acid, as an endogenous signal, is responsible for inducing stress tolerance in plants. In this experiment, the effect of salicylic acid and sodium chloride on growth of bean (Phaseolus vulgaris) was studied. When bean plants were at two-leaf stage, they were sprayed by three concentrations of salicylic acid (0, 0.5 and 1 mM). Then, plants were treated with two concentrations of sodium chloride (zero and 100 mM) for 14 days. The results showed that salinity caused a significant reduction in fresh and dry weight of root and shoot, relative chlorophyll content, percentage of relative water content (RWC) of leaf, stress index and significant increase in proline and soluble sugars as compared to the control treatment. Plants that were treated with both concentrations of salicylic acid showed higher fresh and dry weights. Also, application of salicylic acid in both concentrations, in saline conditions, improved the percentage of leaf RWC, amount of relative chlorophyll and chlorophyll fluorescence (Fv/Fm) of leaves as compared to control plants. In summary, it was concluded that spraying of salicylic acid on bean plants could improve growth and thus resistance to salinity under saline conditions.