Microbial ecology of Fusarium wilt infected and healthy cucumber plant in root zone of continuous cropping soil.

【Objective】 This research studied the microbial ecology mechanism of Fusarium wilt infected and healthy cucumber by exploring soil nutrition and the variation of soil microorganisms in different types of plants and rooting zones.【Method】 Normal method was used to measure the content of soil nutrition,the amount of bacteria,actionmycete,fungi and the ratio of B/F,A/F,B/A in the rhizosphere,surface and external soil by dilution,and semar technique was used to do the molecular biology identification of the dominant microbes and to study the microbial ecology mechanism of Fusarium wilt infected and healthy cucumber in root zone of continuous cropping soil.【Result】 ①The content of available P and K in rhizosphere of infected cucumber plants decreased by 16.3%,16.8% compared with the healthy cucumber.There was no significant difference between healthy and infected cucumber on the value of available N,organic matter,soluble salt and pH.It indicated that the content of available P and K had relationship with incident of cucumber fusarium wilt.②The number of bacteria decreased and the number of fungi increased.The number of bacteria decreased by 16.9% while fungi increased by 56.1%,compared with healthy cucumber plants,of which Fusarium solani and Cladosporium oxysporum increased by 366.15% and 2 201.85% in infected cucumber plants.The B/F,A/F value of the healthy cucumber decreased by 46.8%,36.8% compared with the infected.③The microorgnism quantities in root surface increased for the ulcreation of cucumber root in infected cucumber plants,the number of bacteria,fungi and actinomycetes were 57.3 times,8.9 times and 3.7 times respectively as many as the number of healthy cucumber plants.【Conclusion】 The main reason causing the Fusarium wilt of cucumber is the abnormal microflora of the soil in the root zone and surface.