硅对燕麦幼苗秆锈病抗病能力的作用

Effects of silicon on the resistance of oat seedlings to stem rust

为探究硅在燕麦抗秆锈病过程中的生理功能,以易感秆锈病的燕麦品种‘坝莜1号’为试验材料,采用盆栽方法,分别浇灌含不同浓度(0、0.5、1.0、1.5、2.0、2.5和3.0 mmol/L)K_(2)SiO_(3)的营养液,测定燕麦幼苗秆锈病抗性,叶片光合性能,抗氧化酶活性及渗透调节物质的含量等指标。结果表明:接种秆锈菌条件下,施用1.5 mmol/L K_(2)SiO_(3)可显著提高燕麦幼苗抗秆锈病能力及叶片的光合特性、抗氧化酶活性和渗透调节能力。与0 mmol/L(CK)相比,燕麦幼苗干和鲜重分别提高90.91%和74.71%,叶片叶绿素含量提高18.67%,净光合速率(P_(n))、蒸腾速率(T_(r))、气孔导度(G_(s))和胞间CO_(2)浓度(C_(i))分别提高51.47%、285.71%、285.71%和27.78%,最大荧光(F_(m))、光化学效率(F_(v)/F_(m))和光合性能指数(PI_(ABS))分别提高19.62%、7.69%和5.84%,超氧化物歧化酶(SOD)和过氧化物酶(POD)活性分别提高35.66%和28.88%,丙二醛(MDA)、可溶性蛋白及脯氨酸含量分别降低50.00%、27.45%和16.62%。总之,外源施用K_(2)SiO_(3)能提高燕麦抗秆锈病的能力,且以1.5 mmol/L为最佳浓度。

In order to explore the physiological function of silicon in oat seedlings’resistance to stem rust,the oat variety‘Bayou 1’,which is highly susceptible to stem rust,was used as experimental material.The nutrient solutions containing different K_(2)SiO_(3) concentrations(0,0.5,1.0,1.5,2.0,2.5 and 3.0mmol/L,respectively)were irrigated into pot.The resistance of oat seedlings to stem rust,photosynthetic performance,antioxidant enzyme activity and osmotic regulation substance content of leaves were measured.The results show that:Under the condition of inoculation with stem rust,1.5mmol/L K_(2)SiO_(3) significantly increased the resistance of oat seedlings to stem rust,photosynthetic characteristics,antioxidant enzyme activity and osmotic regulation ability of leaves.Compared with 0mmol/L(CK),the dry weight and fresh weight of oat seedlings increased by 90.91%and 74.71%,respectively.Leaf chlorophyll content increased by 18.67%,net photosynthetic rate(P_(n)),transpiration rate(T_(r)),stomatal conductance(G_(s))and intercellular CO_(2) concentration(C_(i))increased by 51.47%,285.71%,285.71%and 27.78%,respectively.The maximum fluorescence(F_(m)),photochemical efficiency(F_(V)/F_(m))and photosynthetic performance index(PI_(ABS))were increased by 19.62%,7.69%and 5.84%,respectively.The activities of superoxide dismutase(SOD)and peroxidase(POD)were increased by 35.66%and 28.88%,respectively.The contents of malondialdehyde(MDA),soluble protein and proline were decreased by 50.00%,27.45%and 16.62%.In conclusion,the exogenous application of silicon can improve the resistance of oat to stem rust,and 1.5mmol/L is the optimal concentration of silicon.