Silicon nanoparticles alleviate arsenic toxicity in rice (Oryza sativa L.)

Arsenic (As) is one of the most hazardous metalloids for plants, however, little is understood about the role of silicon nanoparticles (Si-NPs) in improving rice tolerance under As toxicity. An experiment was conducted in 2020 at Islamshahr Branch, Islamic Azad University, Islamshahr, Iran, to examine the impacts of As (50 M) and Si-NPs (50 and 100 mg/L) on rice growth, chlorophyll and proline metabolism, antioxidant defense system, ionic homeostasis, and expression of Si/As transporters under hydroponic conditions. The results showed that Si-NPs by boosting the activities of antioxidant enzymes, diminished hydrogen peroxide and superoxide anion, and hence, protected the photosynthetic apparatus and enhanced plant growth during As toxicity. Si-NPs increased Si uptake and declined As uptake in As-treated seedlings by adjusting the relative expression of Si/As transporters (Lsi1, Lsi2, Lsi6). Si-NPs maintained ionic homeostasis under As stress by increasing the uptake of mineral nutrients. In general, Si-NPs increased rice growth and biomass during As toxicity, which might be exploited to develop effective fertilizers to improve crop growth and yield in As-contaminated areas.