Journal of Agronomy and Field Innovations

Background: Oryza sativa L. (rice) is one of the most important cereals as it sustains more than half of the world's population. The problem is that drought events related to climate change are increasingly impacting rice production. Water deficit affects stomatal function, chlorophyll synthesis, and carbon adsorption during photosynthesis, thus limiting biomass and yield.
Objective: The objective of the study is to determine the impact of foliar application of nano-silicon on the photosynthetic reactions, antioxidant protection, osmoregulation, and yield of rice.
Methods: The pot trial was undertaken in a controlled greenhouse using a Completely Randomized Design (CRD) consisting of four types of nano-silicon (0, 50, 100, and 150 mg L⁻¹) and irrigation regimes (well-watered and drought-stressed—40 % of field capacity). The experiment was replicated four times. Quantitative values of gas exchange parameters, chlorophyll content, relative water content, activities of antioxidant enzymes, concentrations of osmolytes, and yield characteristics were recorded.
Results: Drought induced the reduction of net photosynthetic rate, stomatal conductance, and relative water content while bringing to the increase of malondialdehyde and hydrogen peroxide levels (P < 0.05). The application of nano-silicon, particularly in the concentrations of 100–150 mg L⁻¹, helped high levels of chlorophyll content, net photosynthetic rate, superoxide dismutase activity, and catalase activity by 28%, 24%, 35%, and 31%, respectively, compared to the control group with drought-stressed plants. The concentration of proline and soluble sugars in addition to lowering the level of membrane lipid peroxidation and raising the yield level by about 22% in the case of nano-silicon application.
Conclusions: Application of nano-silicon allows plants to be more drought-resistant by improving efficiency of photosynthesis that increases the antioxidant protection of plants at the same time while osmotically adjusting rice plants to dry conditions.