Potassium Silicate-Induced Nitrogen Assimilation and Osmoregulation in Cotton Leaves Under Deficit Irrigation
摘要
Drought stress severely impedes cotton crop productivity and significantly threatens sustainable agricultural ecosystems. While potassium silicate shows the potential to alleviate drought stress, however, its effects on nitrogen assimilation and osmoregulation under deficit irrigation remain unclear. This field study evaluated the impact of potassium silicate at different concentrations (0, 220, and 440 mg L⁻¹) on the Zhong Mian-113 cotton cultivar under three different irrigation regimes (45%, 65%, and 85% field capacity) with four replications and treatments were arranged according to Randomized Complete Block Design (RCBD) Split-plot design where field capacity levels were in the main plot. In contrast, potassium silicates in splits were foliar-applied Potassium silicates during the flowering stage of cotton. The experiment was conducted over two consecutive growing seasons (2023–2024). The 45% and 65% FC levels reduced leaf relative water content by 13.6% and 5.44%, and osmotic potential by 18.6% and 9.21%, respectively, compared to full irrigation (85 FC). Foliar Application of potassium silicate at 440 mg L⁻¹ significantly improved the osmotic adjustment by promoting the accumulation of amino acids, total soluble sugars, and nitrate concentrations, which increased by 32.7%, 26.6%, and 28.4% at 45% FC over potassium silicate of o mg L− 1, respectively. Moreover, potassium silicate (440 mg L⁻¹) application improved soluble protein content and chlorophyll levels by 35.6% and 28.4%, respectively, at 45% FC compared to Water Spray. These findings suggested that potassium silicate is critical for improving osmotic regulation and nitrogen metabolism in cotton plants, thereby helping them tolerate water-deficit conditions. This sustainable approach enhances cotton productivity under water stress; future research should explore its genetic basis.