Effects of different silicon agents on growth and physiological characteristics at heading stage of rice under salt stress

To investigate the effects of silicon (Si) on rice resistance to salt stress, a pot experiment was conducted by applying different organic silicon agents: aminosiloxane-containing sol (Si-50G), epoxy-siloxane-containing sol (Si-60G), tetramethoxysiloxane-containing sol (Si-TG) during the tillering stage of rice. The impacts on rice growth and physiological characteristics at heading stage under salt stress were analyzed. Results show that silicon application significantly increases rice biomass and plant height under salt stress. Under alkaline salt stress, Si-60G enhances biomass by 9.4% - 10.8%, while Si-TG increases plant height by 10.4% - 12.5%. Under neutral salt stress, Si-50G improves biomass by 6.9% - 9.7% and plant height by 8.9% - 13.0%. Silicon agents also significantly enhance stress resistance in rice leaves, increasing chlorophyll content and soluble sugar content by 18.1% - 44.2%, 8.4% - 28.2%, and also increaseing antioxidant enzyme activity, while reducing relative conductivity and malondialdehyde (MDA) content by 4.6% - 24.3% and 12.4% - 28.9%, respectiveley. Under alkaline salt stress, Si-60G exhibits the best improvement in rice growth and leaf physiology, whereas the optimal concentrations and rates for Si-50G and Si-TG require further investigation. Under neutral salt stress, Si-50G performs optimally. Silicon agents significantly increase rice yield, with Si-60G being optimal under alkaline salt stress and Si-50G being optimal under neutral salt stress.