Effect of Different Forms of Silicon Application on Wheat Aphid Resistance

Based on the view of plant basic metabolism, the mechanism of different forms of silicon on reducing wheat aphid density was discussed to provide scientific basis for ecological regulation of wheat aphids in the field. Five treatments were applied: Control, Nano-silicon, tetraethyl orthosilicate (TEOS), Na 2 SiO 3 and K 2 SiO 3 . Solution culture experiment was conducted to set up five spraying silicon treatments (Control, Nano-silicon, tetraethyl orthosilicate (TEOS), Na 2 SiO 3 and K 2 SiO 3 ) to carry out aphid infestation when wheat has five expanded leaves. The density of aphids was surveyed and the wheat samples were collected, respectively, at the 4th and 8th day after the aphid infestation, and the effects of different forms of silicon on the contents of free amino acids, soluble proteins, soluble sugars and silicon in wheat leaves after aphid infestation were analyzed. The density of aphids on wheat plants treated with different forms of silicon was significantly lower than that of Control 4 days and 8 days after aphid infestation, and TEOS treatment had the lowest density of wheat aphids. On the 4th and 8th day of aphid infestation, compared with Control treatment, the contents of free amino acid and soluble protein in wheat plants sprayed with silicon treatment were significantly reduced, the contents of soluble sugar and leaf silicon were significantly increased, and TEOS treatment had the most obvious effect. After the 4th and 8th day of aphid infestation, the contents of free amino acid and soluble protein were, respectively, reduced by 45.16 and 78.16%, the contents of soluble protein were, respectively, reduced by 48.82 and 95.26%, the contents of soluble sugar were, respectively, increased by 18.50 and 36.69%, and the contents of leaf silicon were, respectively, increased by 69.05 and 77.05%. The results of correlation analysis showed that the density of wheat aphids was significantly positively correlated with the contents of free amino acids and soluble protein, and significantly negatively correlated with the contents of soluble sugar and silicon in leaves 4 and 8 days after aphid infestation. Spraying different forms of silicon (silicon content 3 mmol L −1 ) could reduce wheat aphid density, of which TEOS treatment had the best effect. Silicon could improve wheat aphid resistance by increasing the content of silicon and soluble sugar, and by reducing the content of free amino acids and soluble proteins in wheat leaves.