Alleviating Adverse Effects of Salt Stress on Strawberry by Application of Salicylic Acid and Methyl Jasmonate

Salinity is one of the most common environmental stresses which adversely affect crop growth and productivity. Salicylic acid and methyle jasmonate increase tolerance of plants to biotic and abiotic stresses. Therefore, the aim of this study was to examine the effects of exogenous salicylic acid and methyle jasmonate on vegetative growth of strawberry (Fragaria ananassa cv. ‘Camarosa’) under salinity stress conditions. In this regard, a factorial experiment, in a completely randomized design (CRD) with three replications was used to investigate the effects of three salinity levels (0, 30 and 60 mM NaCl) and various levels of salicylic acid (0, 0.1, 0.5 or 0.75 mM) and methyle jasmonate (0, 0.25, 0.5 or 0.75 mM). The results indicated that by increasing the levels of salinity stress, vegetative characters (petiole diameter, petiole length, leaf numbers, fresh and dry weight of shoot and roots), significantly decreased but application of exogenous salicylic acid and methyle jasmonate significantly improved the most vegetative characters above. Salt stress decreased the relative chlorophyll content. Salicylic acid (0.1 mM) and methyle jasmonate (0.75 mM) improved the relative chlorophyll content. Also by increasing the levels of salinity stress, Na/K ratio in roots and shoots were increased, salicylic acid and methyle jasmonate decreased this ratio in the shoots with no effect in the roots. Peroxidase activity was increased in salt stress conditions and 0.5 mM salicylic acid and 0.25 mM methyl jasmonate increased the activity of this enzyme. In brief, the salicylic acid and methyle jasmonate treatment reduced the damaging effects of salinity.