1. Introduction

Abiotic stresses are a potential threat to agricultural productivity all over the world. Anthropogenic activities provoked the degradation of the agricultural system. Drought, excess soil salinity, extreme high, and low temperatures, metals/metalloids, ozone, UV-B radiation, nutrient (deficiency and excess) are the abiotic stresses which have increased many more times than previous due to anthropogenic activities [1, 2]. It has been projected that abiotic stresses may adversely affect 70% yield of staple food crops and decrease overall crop production by more than 50% [3, 4]. Thus, to improve plant performance and to reduce the loss of productivity

© 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

caused by abiotic stress is vital. This can be implemented through various approaches and one of those is the application of exogenous phytoprotectant molecule.

Salicylic acid or orthohydroxy benzoic acid is ubiquitously distributed plant growth regulator [5]. Salicylic acid has positive effects on plant growth and developmental processes [5–7]. Research findings demonstrated its roles in seed germination, glycolysis, flowering, fruit yield [8], ion uptake and transport [9], photosynthetic rate, stomatal conductance (gs), and in transpiration [10]. Salicylic acid can modulate antioxidant defense system thereby decreasing oxidative stress [11]. Photosynthesis, nitrogen metabolism, proline (Pro) metabolism, production of glycinebetaine (GB), and plant-water relations in abiotic stress affected plants were regulated by SA [12–14]. Induction of defense-related genes and stress resistance in biotic stressed plants have also been reported [15]. Moreover, exogenously applied SA showed putative positive effects on stressed plants [16–20]. Salicylic acid induced genes encoding chaperone, heat shock proteins (HSPs), antioxidants, and secondary metabolites of different types. Moreover, SA was involved in mitogen-activated protein kinase (MAPK) regulation, and in the expression [21]. There is no doubt about the vital roles of SA under abiotic stress condition. So, we will review and cover the area regarding the biosynthesis, involvement, and role of salicylic acid on abiotic stress affected plants.
