Regulation of Photosynthesis by Salicylic Acid Under Optimal and Suboptimal Conditions

Abstract

Salicylic acid (SA) is an imperative plant hormone that regulates plant growth, photosynthesis, and different metabolic processes. SA as a signaling molecule plays an imperative role in plant acclimation against different abiotic stresses. The impact of exogenously applied SA on the processes of photosynthesis under optimal and suboptimal conditions is controversial. The SA application improves the stomatal conductance, electron transportation, and antioxidant activities at lower concentration and thus improves the photosynthetic efficiency. The mode of SA action depends on the plant species, environmental conditions and method, and the dose of SA application. The suboptimal environmental conditions can increase the endogenous SA levels which provide them protection against these conditions. Moreover, exogenously applied SA alleviates the negative effects of different stresses and improves the plants’ photosynthetic efficiency and their acclimation to changing environmental conditions. Therefore, in this chapter, we discussed the role of SA on photosynthesis under normal and stressed conditions.