适宜浓度的硅可提高茄子青枯病抗性和抗氧化酶活性

Silicon Could Enhance the Resistance to Bacterial Wilt and Increase the Antioxidant Enzymes Activity

以高感青枯病的茄子品种"快圆茄"为实验材料,在水培条件下,分别用含不同浓度(0、0.5、1.0、1.5、2.0、2.5 mmol/L)K_2SiO_3的营养液培养茄苗,研究不同浓度的硅对茄苗干物质积累的影响;接菌条件下,研究不同浓度的硅对青枯病的防治效果以及关键抗氧化酶活性的影响。结果表明:接菌前,与其他处理相比,1.5 mmol/L和2.0 mmol/L硅处理均显著增加茄苗的干物质重、根部和茎部硅含量;接菌后,两个处理的根系活力一直显著高于其他处理,而MDA含量及病情指数均显著低于其他处理,其防病效果分别达36.77%和37.43%。整个侵染过程中,上述2个处理的PAL和PPO活性均显著高于其他几个浓度处理,至接菌13 d后,1.5 mmol/L和2.0 mmol/L硅处理的PAL活性分别比0.0 mmol/L硅处理(对照)高55.32%和59.87%;而PPO活性则分别高52.38%和49.77%。同时,茄苗青枯病病情指数与根部硅含量、PAL和PPO活性呈极显著负相关,而与根部MDA含量表现为极显著正相关。综合评价不同硅浓度处理对茄苗促生效果和防病效应,以1.5~2.0 mmol/L的硅浓度处理较为适宜。

The susceptible variety eggplant（Kuaiyuan） was grown hydroponically to study the effect of different concentration of K2SiO3（0, 0.5, 1.0, 1.5, 2.0 and 2.5 mmol/L） on dry weight of plants, and the effect on the control efficacy against bacterial wilt, and the activities of key antioxidant enzymes after inoculation. The dry weight of plant and the content of Si in eggplant roots and stems significantly increased with the treatment of 1.5 mmol/L and 2.0 mmol/L K2SiO3 compared to the others. After inoculation, the root activities of plants treated with 1.5 mmol/L and 2.0 mmol/L K2SiO3 were significantly higher than that of the other treatments. Meanwhile, the content of MDA and the severity index were significantly lower compared to the other treatments. The relative immunization efficiency treated with 1.5 mmol/L and 2.0 mmol/L K2SiO3 reached 36.77% and 37.43% respectively. During the whole process of infection, the activity of PAL and PPO treated with 1.5 mmol/L and 2.0 mmol/L K2SiO3 were significantly higher than that of the other treatments. After 13 days infection, the activity of PAL was 55.32% and 59.87% higher to the control, whereas the activity of PPO was 52.38% and 49.77% higher to the control, respectively. There was a negative correlation between severity index and silicon content in roots, and between severity index and PAL and PPO activities, but a positive correlation with the content of MDA. To comprehensively evaluate the effect of silicon to control bacterial wilt occurrence in eggplant and promote plant growth, the concentration of silicon from 1.5 mmol/L to 2.0 mmol/L is better than other concentration.