Microbial ecology of Fusarium wilt infected and healthy cucumber plant in root zone of continuous cropping soil | 连作黄瓜枯萎病株、健株根域土壤微生物生态研究

Chinese. 对黄瓜病株与健株根区土的理化性质及根区土和根表土中的微生物区系特征进行比较，探索连作黄瓜枯萎病发生的微生态机制。采用常规方法测定土壤养分含量，稀释平板涂抹法测定黄瓜根区土、根表土、根外土中细菌（B）、真菌（F）和放线菌（A）的数量并计算其比值（B/F、A/F、B/A），同时对优势细菌、真菌和放线菌进行了分子生物学鉴定，研究连作黄瓜枯萎病株、健株根域土壤微生物生态的变化。① 病株根区土中的速效P、速效K含量分别较健株降低了16.3%和16.8%，病株、健株根区土中速效N、有机质、水溶性盐分含量及pH无差异，说明土壤速效P、速效K含量与黄瓜枯萎病发生有一定关系。② 连作黄瓜根区土中的细菌数量大幅度下降，真菌数量大幅度增加；与健株相比，病株的细菌数量减少了16.9%，真菌数量增加了56.1%；病株根区土中的优势病原真菌茄病镰刀菌（Fusarium solani）及尖孢枝孢菌（Cladosporium oxysporum）数量分别较健株增加了366.15%和2 201.85%；病株B/F、A/F值较健株分别降低了46.8%和36.8%。③ 黄瓜根系染病溃烂导致黄瓜根表土中的细菌、真菌和放线菌数量急剧增加，病株根表土中的细菌、真菌及放线菌数量分别是健株的57.3，8.9及3.7倍。根区土和根表土中的微生物区系异常是黄瓜枯萎病发生的主要原因。

English. 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. 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. ① The 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. ② The 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. ③ The 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. The main reason causing the Fusarium wilt of cucumber is the abnormal microflora of the soil in the root zone and surface.