Genotype-dependent aveliation of water deficit stress in broad bean by silicon application

Prolonged water stress can have detrimental effects on most plants, including Vicia faba L. (broad bean), which is an important legume. The use of exogenous coarse or nano-structured silicon on various plants has yielded conflicting results in terms of improving plant water relations and alleviating drought stress. Therefore, the objective of this study was to examine the effects of exogenously applied silicon and nano-silicon on the morpho-physiological responses of three recently introduced Vicia faba genotypes during the vegetative growth stage under water deficit stress. In a greenhouse experiment, three genotypes, two levels of irrigation regimes, and three levels of silicon were arranged in a completely randomized factorial design, with five replications. The results indicated that water deficit stress significantly reduced shoot height, as well as shoot and root fresh and dry weights, while also decreasing relative water content in all three genotypes. Conversely, chlorophyll, carotenoid, malondialdehyde (MDA) content, and soluble guaiacol peroxidase activity increased in response to water stress. Notably, the G62 genotype exhibited greater sensitivity to water stress compared to G20 and G61, based on guaiacol peroxidase activity and MDA content. Furthermore, the effects of silicon and nano-silicon on the morpho-physiological characteristics of the plants were found to be minimal, but were significantly influenced by the genotype and experimental conditions. These findings suggest that before the wide application of exogenous silicon in field trials, particularly in mitigating the adverse effects of water deficit during the vegetative stage of Vicia faba , prior testing of genotype-specific responses is necessary.