Boosting Drought Tolerance in Tomatoes through Stimulatory Action of Salicylic Acid Imparted Antioxidant Defense Mechanisms

Abstract

Drought poses a significant threat to agricultural productivity, particularly affecting economic crops like tomatoes. To address this challenge, various alternatives have been explored, including the use of elicitors or biostimulants such as salicylic acid (SA). This study aims to assess the stimulatory action of SA in alleviating drought stress in tomato plants under greenhouse conditions. The experiment was designed with two main factors: water availability (controlled versus drought) and the foliar application of SA at four different concentrations ranging from 100 to 250 mg L−1. The application of SA, particularly at a concentration of 250 mg L−1, showed promising results in mitigating the adverse effects of drought stress followed by 200 mg L−1. This was evidenced by the increased activity of antioxidant enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT). Gene expression analysis revealed optimal APX expression with SA application at concentrations of 200 mg L−1 or 250 mg L−1. Additionally, the application of SA at 250 mg L−1 led to a high accumulation of bioactive compounds without compromising yield. Furthermore, SA application positively influenced both shoot and root weights, with the highest values observed at a concentration of 250 mg L−1. While SA is known to enhance plant tolerance to abiotic stress, further research is needed to fully elucidate its biochemical, physiological, and molecular mechanisms in supporting plant tolerance to drought stress. Utilizing salicylic acid can help growers mitigate environmental stresses, enhancing tomato crop yield and quality. Integrating SA treatments into agriculture offers a sustainable alternative elicitor for ensuring food security under challenging climate conditions.