Exogenous silicon alleviates aluminum phytotoxicity in Fagopyrum esculentum Moench by modulating physiological and antioxidant responses

Silicon (Si) as silicic acid, Si(OH)4 offers several benefits to the growth of plants, especially under adverse environmental conditions. Therefore, the present study aimed to assess the role of exogenous Si treatments (0.5 and 1.0 mM) in the tolerance of Fagopyrum esculentum Moench to Al stress applied at two different concentrations (0.2 and 0.4 mM). A set of agrophysiological, biochemical and antioxidant parameters were evaluated during the investigation. The exogenous Si application to Fagopyrum esculentum plants exposed to Al treatments significantly modulated the physiological and antioxidant responses to overcome the Al phytotoxicity and provide beneficial effects. The results indicated that the application of different doses of Al significantly affected the physiological parameters viz., plant growth, tolerance index, biomass accumulation (BA), relative water content (RWC), lipid peroxidation (LP), membrane stability index (MSI) and reduced glutathione (GSH) content. Likewise, aluminum -treated leaves also displayed increased hydrogen peroxide accumulation signifying the extent of the damage in F. esculentum. However, the individual and combined doses of silicon (Si) yielded beneficial effects on the physiological and antioxidant attributes. Multivariate analysis also suggested that individual and combined doses of Si improved physiological (root length (RL), shoot length (SL), root and shoot tolerance index (TI), BA, RWC, MSI and osmolytes) and modulates antioxidant defense enzymes (SOD, APX, GPX, CAT, GR and GST). The study reveals that exogenous Si application acts as a potent stress -modulating agent either via the formation of aluminum -silicate complexes or by improving the efficiency of antioxidant enzymatic activities in Al -contaminated soils. (c) 2024 SAAB. Published by Elsevier B.V. All rights reserved.