Silicon, by modulating homeostasis and nutritional efficiency, increases the antioxidant action and tolerance of bell peppers to phosphorus deficiency

Abstract

The effects of phosphorus deficiency on bell pepper cultivation and the role of silicon in mitigating this deficiency warrant further investigation. The use of silicon could be a promising sustainable alternative to increase the tolerance of this vegetable to P-deficient environments, which is a worldwide issue, but the mechanisms involved need to be elucidated. To this end, this research aimed to investigate the impact of Si on mitigating P deficiency in bell pepper plants, exploring its effects on nutritional homeostasis and physiological parameters under conditions of P sufficiency and deficiency. This study was conducted under controlled conditions with two P conditions (deficiency and sufficiency) combined with two Si conditions (0.0 and 2.0 mM) arranged in a completely randomized design with five repetitions. We found that P deficiency damage in bell pepper plants compromised the nutritional efficiencies of P and N, photochemical efficiency, total soluble sugar production, and growth, but the adaptive response of the plant to mitigate these damages induced non-enzymatic antioxidant defense mechanisms and favored homeostasis by increasing the C/N, C/P, and N/P ratios. This occurred because Si favored stoichiometric homeostasis of C/N, C/P, and N/P in the plant while simultaneously reducing stress with substantial increases in the production of antioxidant compounds, such as ascorbic acid, phenolic compounds, anthocyanin, carotenoids, and photosynthetic pigments, enhancing photochemical efficiency and C use, and consequently, plant growth. This study offers a sustainable option for addressing P deficiency using Si, strengthening large-scale horticulture, given the common occurrence of P-limited growing environments.