Application of silicon and gibberellic acid modulate photosynthetic capacity and antioxidative defense machinery in Saccharum officinarum cv. GT55

Silicon (Si) is a relatively novel element that has found widespread application in various fields. Gibberellic acid (GA₃) is known to induce different physiological traits in a variety of plants. While Si and GA₃ independently improve plant performance, their interactive mechanisms and potential synergy are poorly understood. In the present study, different treatments of GA₃ (0, 10, 20, 50, 75 and 100 ppm) and Si (50 ppm) were applied as foliar and soil irrigation on sugarcane (Saccharum officinarum L. cv. GT55) plants at specific time intervals, such as 60 and 90 days. The result findings indicated that the application of foliar and soil irrigation containing GA₃ and Si notably enhanced and/ or stabilized enzymatic and non-enzymatic activities, i.e., soluble protein, catalase, peroxidase, ascorbate peroxidase, superoxide dismutase, glutathione reductase, hydrogen peroxide, lipid peroxidation, proline, ascorbate, glutathione, oxidized glutathione, glutathione-S-transferase, dehydroascorbate, and plant hormones, such as indole-3-acetic acid, abscissic acid, and gibberellic acid in sugarcane plant leaves and roots after foliar and soil irrigation application. The results showed that the interactive applications of GA₃ and Si were not harmful to sugarcane plants, and positively affected their growth and development. The simultaneous application of Si and GA₃ is a safe and highly effective strategy to upregulate sugarcane growth and metabolic regulation. This innovative approach presents sustainable technology to enhance crop productivity and contribute to global food security goals without relying on conventional chemical inputs.