Salicylic acid: an effective growth regulator for mitigating salt toxicity in plants

Salinity is a harmful environmental factor threatening plant growth and productivity through ionic and oxidative stresses. These detrimental effects of salinity could be modulated by some plant growth regulators. Salicylic acid (SA) as a phenolic molecule regulates growth and development and also induces crucial defense mechanisms in plants under salinity. This growth regulator can also improve some physiological and biochemical processes of salt-stressed plants such as reducing Na+ influx to the root cells and increasing essential nutrients uptake. Application of SA can also help plants to accumulate the toxic Na+ in vacuoles through enhancing the activities of H+-pum- stressed plants. Some reports indicate that salicylic acid counteracts salt-induced water deficit by elevating plant osmolytes including soluble sugars, proline, and glycine betaine. These essential roles as well as the effect of SA in the augmentation of chlorophyll and photosynthetic activities can potentially improve plant growth and productivity under saline conditions. The possible cross-talks of salicylic acid with other growth regulators are also important for promoting salt tolerance and the performance of plants under stressful conditions.