防御酶系对山茶灰斑病诱导抗性的响应

Response of the defense enzymes to induced resistance of camellia gray spot

为揭示水杨酸（SA）诱导山茶产生抗病性反应机制,采用琼脂平板法测定了SA对山茶灰斑病菌Pestalotiopsis guepinii（Desm.）Stey的影响。结果表明,浓度为0~5mmol/L的SA对该菌的生长没有抑制作用。用SA喷雾涂布叶片诱导山茶抗性,其植株内过氧化物酶（POD）、多酚氧化酶（PPO）、过氧化氢酶（CAT）、苯丙氨酸解氨酶（PAL）等防御酶对山茶灰斑病菌诱导信号有不同响应。诱导并挑战接种处理的植株体内上述酶活性比只诱导不接种处理上升速度快,不同浓度的SA诱导及诱导后挑战接种植株体内的POD、PPO、CAT、PAL活性与SA浓度呈正相关。各防御酶活性与感病指数的相关性分析表明,CAT活性与感病指数显著负相关（r=-0.9730）,除PPO与感病指数的相关系数很低外,其它酶均较高,尽管未达到显著水平,但仍说明POD、PAL在诱导山茶抗病性中具有重要作用。

To reveal the response mechanism of salicylic acid（SA） to induced resistance of camellia,the effect of SA to Pestalotiopsis guepinii（Desm.） Stey was determined using the agar plate method.The results showed that the concentration of SA at 0-5 mmol/L had no inhibition effect to the growth of the pathogen.The defense enzymes such as speroxidase（POD）,polyphenol oxidase（PPO）,catalase（CAT） and phenylalanine amonnialyase（PAL） had different responses to the disease resistance of camellia induced by spraying SA.The enzymes treated with both inducement and challenge inoculation were faster than those only treated with inducement in the plants.The activities of POD,PPO,CAT,and PAL with different concentrations of SA inducement and challenge inoculation had the positive correlations with the concentration of SA.The correlation analysis showed that the CAT activity had significant correlation（r=-0.9730） with infection index.However,the rest enzymes didn＇t show significant correlations with infection index,but still had high correlation coefficients except PPO,indicating that POD and PAL played important roles in the induced resistance.