Silicon Alleviates Potassium Deficiency in Plants by Improving Photosynthesis, Antioxidant Defenses, Water Use Efficiency, and Potassium Use Efficiency: a Meta-analysis

Potassium (K) deficiency is a widespread nutritional stress that reduces crop productivity and impairs plant physiological functions. Although silicon (Si) is not considered essential, it has been shown to mitigate various abiotic stresses. This study aimed to assess the effectiveness of Si supplementation in alleviating K deficiency effects in plants through a comprehensive meta-analysis. A meta-analysis was conducted using 183 observations extracted from 13 peer-reviewed studies comparing K-deficient plants with and without Si application. Standardized mean differences (SMD) were calculated for physiological, biochemical, and nutritional variables. Random-effects models and meta-regression analyses were used to examine the influence of moderators such as plant genotype, Si source, application method, and stress severity. Silicon supplementation significantly improved photosynthetic performance (SMD + 1.85), antioxidant enzyme activity (SMD = + 2.37), water use efficiency (SMD = + 2.79), and potassium use efficiency (SMD = + 2.68) under K deficiency. Oxidative stress markers such as malondialdehyde (MDA), hydrogen peroxide (H₂O₂) were reduced by 45%. The magnitude of these effects varied according to Si source, plant accumulation capacity, and application method, with nanosilicon and root application showing superior outcomes. This study provides quantitative evidence that silicon mitigates the adverse effects of potassium deficiency by enhancing photosynthesis, water relations, antioxidant defenses, and K use efficiency. These findings support the integration of Si into nutrient management strategies, especially for crops grown in K-deficient or stress-prone environments.