Abstract: 【Aim】 This study aims to explore the physiological responses of silicon-treated rice plants to feeding stress by the white-backed planthopper, Sogatella furcifera, so as to provide a theoretical foundation for the rational use of silicon fertilizer in controlling S. furcifera. 【Methods】 The plants of the susceptible rice variety TN1 were treated with two silicon application levels ［grown in nutrient solution added with sodium silicate (Na₂SiO₃·9H₂O) at the concentration of 112 mg/L(Si+treatment group), and without addition of silicon (control group)］, then exposed to the feeding of the 3rd instar nymphs of S. furcifera. The contents of superoxide anion (O^-·₂), hydrogen peroxide (H₂O₂) and malondialdehyde (MDA), the activities of antioxidant enzymes ［superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT)］ and defense enzymes ［phenylanlanine ammonialyase (PAL), polyphenol oxidase (PPO) and lipoxygenase (LOX)］, and lignin content in rice leaf sheaths were measured at 0, 12, 24, 48, 72 and 96 h after feeding on the rice plants in the Si+ treatment group or the control group. 【Results】 Compared to the control group, the Si+ treatment group exhibited significant reductions in O^-·₂ content by 7.8%-17.9% in rice leaf sheaths during 12-72 h after S. furcifera feeding, in H2O2 content by 15.5%-43.1% in rice leaf sheaths during 12-96 h (except at 24 h) after S. furcifera feeding, and in MDA content by 15.1%-35.3% in rice leaf sheaths during 24-96 h after S. furcifera feeding. During 12-96 h (except at 72 h) after S. furcifera feeding, the CAT and SOD activities in rice leaf sheaths in the Si+ treatment group were significantly increased by 25.8%-44.8% and 21.4%-47.6%, respectively, as compared to those in the control group. During 12-72 h (except at 24 h) after S. furcifera feeding, the POD activities in rice leaf sheaths in the Si+ treatment group significantly increased by 19.1%-54.5%, as compared to those in the control group. During 12-72 h after S. furcifera feeding, the PAL and PPO activities in rice leaf sheaths in the Si+ treatment group were significantly elevated by 17.6%-70.8% and 16.7%-38.3%, respectively, as compared to those in the control group. During 12-96 h after S. furcifera feeding, the LOX activities in rice leaf sheaths in the Si+ treatment group significantly increased by 9.9%-105.4%, as compared to those in the control group. During 12-96 h (except at 48 h) after S. furcifera feeding, the lignin contents in rice leaf sheaths in the Si+ treatment group significantly raised by 12.5%-59.3%, as compared to those in the control group. 【Conclusion】 Silicon application enhances rice resistance to S. furcifera by reducing reactive oxygen species and MDA contents, as well as by increasing the activities of antioxidant enzymes and defense enzymes, and the lignin content in rice leaf sheaths infested by S. furcifera.

Key words: Rice; Sogatella furcifera, silicon, reactive oxygen species, antioxidant enzymes, defense enzymes