香蕉枯萎病菌4号生理小种对香蕉根际土壤微生物及酶活性的影响

Effects of Fusarium oxysporum f.sp.cubense race 4 on microorganisms and enzyme activities in the rhizosphere soil of banana

为探明香蕉枯萎病的发病机理,以巴西香蕉为材料,采用盆栽试验,研究香蕉枯萎病4号生理小种(Fusarium oxysporum f.sp.cubense race 4,Foc4)对香蕉根际土壤微生物和土壤酶活性的影响。结果表明:接种Foc4对香蕉根际土壤微生物总量和细菌数量(B)影响不大,但显著提高了真菌数量(F)及其在整个微生物中的比例,显著降低了放线菌数量(A)及其在整个微生物中的比例;B/F及A/F显著降低;根际土壤中过氧化氢酶和转化酶活性显著升高;Foc4侵染改变了香蕉根际土壤中微生物的数量,导致其种群结构失衡,这可能是导致香蕉枯萎病发生的重要因素之一;Foc4侵染后香蕉根际土壤酶活性发生显著变化,这可能是香蕉通过改善其根际微环境来应对病菌侵染的重要自我保护机制。

To reveal the pathogenesis of Fusarium wilt in banana,the effects of Fusarium oxysporum f.sp.cubense race 4（Foc4） on microorganism quantities and enzyme activities in the rhizosphere soil of potted banana（Musa AAA Cavendish subgroup cv.Baxi） were studied.The results showed that Foc4 had little effects on the total amount of microorganisms and the quantity of bacteria（B）.But it significantly increased the quantity and percentage of the fungi（F） in the total microorganisms,decreased tho se of the actinomycete（A） and reduced the values of bacteria/fungi（B/F） and actinomycete/fungi（A/F）.In addition,Foc4 significantly improved the activities of catalase and invertase.The findings revealed Foc4 infection affected the quantities of rhizosphere microorganisms,thus made the population structure unbalanced,which might be one of the main factors causing Fusarium wilt.That the activities of soil enzyme in banana rhizosphere changed significantly might be an important self-protection mechanism by improving the resistance of the rhizospheric microenvironment to fungi infection.