Effect of Salicylic Acid Treatment on Agro-Morphological Performances, Mineral Nutrition, Antioxidant Capacity, and Steviol Glycosides Content of Stevia Subjected to Salt Stress

Abstract

The plants are often exposed to a variety of abiotic stresses that affect their yield negatively, among which, we found salt stress caused by accumulation of salts in soil. Currently, different approaches are used to reduce the detrimental effect of salt stress on plants. In light of these circumstances, the present work aims to improve the tolerance of Stevia rebaudiana Bertoni to salt stress (0 and 80 mM) using salicylic acid (0, 0.1, and 0.5 mM). The results showed that salt stress affects negatively the mineral nutrition, antioxidant activities (ABTS, FRAP, and DPPH), and steviol glycosides production. However, exogenous application of salicylic acid attenuated the depressive effects caused by salt stress by reinforcing the antioxidant system and the synthesis of osmoprotectants such as glycine betaine (54%), total soluble sugars (17%), proline (18%), and steviol glycosides (stevioside and rebaudioside A). Moreover, salicylic acid countered the decline in K (30%), P (33%), and Ca (33%) content induced by salt stress. This fundings supported that the application of salicylic acid to salt-stressed stevia plants is a promising approach to improve the salinity tolerance.