Study on relationship among microorganism, enzymes’ activity in rhizosphere soil and root rot resistance of grafted pepper | 嫁接辣椒根际土壤微生物及酶活性与根腐病抗性的关系

chinois. 【目的】探讨嫁接辣椒的抗病机理,为合理调控根域生态环境,减轻根腐病危害提供理论依据。【方法】以‘卫士’辣椒为砧木,以‘新丰2号’为接穗嫁接,自根辣椒为对照(CK),通过人工接种根腐病菌,研究砧木、嫁接和自根辣椒发病率及病情指数、根系吸收面积与呼吸强度及根际土壤微生物种群数量和酶活性的变化。【结果】接种根腐病菌前,砧木和嫁接辣椒的根系吸收面积、根际土壤放线菌数量和比例及脱氢酶、过氧化物酶、过氧化氢酶活性显著高于CK。接种后嫁接辣椒的发病率和病情指数显著低于CK,但高于砧木;砧木和嫁接辣椒的根系吸收面积与活跃吸收面积、根际土壤微生物数量及放线菌比例均显著大于CK,土壤酶活性也明显高于CK,呼吸强度前期比CK低,后期较CK高。【结论】嫁接辣椒根系吸收面积增大,根际土壤微生物数量、放线菌比例增加及酶活性提高是其根腐病抗性增强的重要原因。

anglais. 【Objective】 The purpose of this study is to elucidate the mechanism of root rot resistance in grafted pepper (Capsicum annuum L.), and offer a theoretical basis for regulating root environment and alleviating root rot damage. 【Method】 Changes of disease incidence and disease index of root rot in rootstock (‘Weishi’), grafted (‘Xinfeng 2’ scion grafted onto ‘Weishi’) and own-root plants (‘Xinfeng 2’, control) of pepper, root absorption area, root respiration intensity, population of microoganism and enzymes’ activity in rhizosphere soil were investigated by manual inoculation. 【Result】 The results showed that the root absorption area, actinomyces population and ratio, activities of dehydrogenase, peroxidase and catalase in rhizosphere soil of rootstock and grafted peppers increased significantly compared with those of control before inoculation. After been inoculated, grafted plants showed remarkable lower disease incidence and disease index than control plants, but higher than rootstock plants. Rootstock and grafted peppers had significant higher root absorption area and active absorption area, quantities of bacterium, fungus and actinomyces, actinomyces ratio, and soil enzymes’ activity, in comparison with control. The root respiration rate was lower in rootstock and grafted plants than in control plants at earlier stage, but just the opposite at later stage. 【Conclusion】 The observed increase in root absorption area, quantity of microoganism, ratio of actinomyces, and enzymes’ activity in rhizosphere soil of grafted peppers are important reasons of enhancement of root rot resistance.