Effects of silicium (Si) applications on the development and some physiological characteri̇stics of sunflower varieties under salt stress conditions

This study aims to investigate the effects of different silicium (Si) and salt (NaCl) applications on the physiological changes and growth of three different sunflower (Helianthus annuus L.) varieties (Pegaz, Buleria, Sumo Granstar). The experiment was conducted in the climate chamber of the Aksaray University Scientific and Technological Application and Research Center (ASÜBTAM). Different concentrations of salt (0, 50, 100, 150, 200 mM NaCl) and silicium (0, 50, 100, 200 ppm) were applied through soil and foliar methods, and the shoot and root lengths, fresh and dry weights, chlorophyll and carotenoid contents, relative water content, and electrolyte leakage of the sunflowers were measured. It was observed that silicon applications increased the shoot and root lengths, fresh and dry weights, and chlorophyll and carotenoid contents in plants exposed to salt stress. It was also observed that silicium applications supported water management by maintaining relative water content and reduced electrolyte loss by enhancing the resilience of cell membranes. It was observed that silicium enhanced the plants' resistance to salt stress, creating positive effects on plant health and productivity. Keywords: Sunflower, Salt Stress, Silicium, Physiological Effect.