摘要：A field experiment was carried out from 2003 to 2013 in the Wanzhong Farm of the Hainan Island, China, to determine the effects of two long-term banana rotations on the abundance and trophic groups of soil nematode communities in the island. The experiment was set out as a randomized complete block design with three replications of three treatments： banana-pineapple rotation （AB）, banana-papaya rotation （BB） and banana monoculture （CK） in a conventional tillage system. Soil samples were taken at depths of 0-10, 10-20 and 20-30 cm, and nematodes were extracted by a modified cotton-wool filter method and identified to the genus level. Nematode ecological indices of Shannon-Weaver diversity （Ht）, dominance index （A）, maturity index （MI）, plant parasite index （PPI）, structure index （SI）, enrichment index （EI）, and channel index （CI） were calculated. A total of 28 nematode genera with relative abundance over 0.1% were identified, among which Tylenchus and Paratylenchus in the AB, Thonus in the BB, Tylenchus and Helicotylenchus in the CK were the dominant genera. The rotation soils favored bacterivores, fungivores and omnivores-predators with high colonizer-persister （c-p） values. Soil food web in the rotation systems was highly structured, mature and enriched as indicated by SI, MI and EI values, respectively. Higher abundance of bacterivores and lower values of CI suggested that the soil food web was dominated by a bacterial decomposition pathway in rotation soils. Nematode diversity was much higher after a decade of rotation. Soil depth had significant effects on the abundance of soil nematodes, but only on two nematode ecological indices （λ and MI）.

摘要：香蕉枯萎病发病率与土壤中香蕉枯萎病菌FOC4的数量密切相关。为了在香蕉定植前准确检测土壤中FOC4的数量,本研究以本实验室克隆的FOC4特异性基因片段作为标准线性片段,设计特异性荧光定量引物:以标准线性片段为模板建立荧光定量标准曲线,以无FOC4的土壤配置FOC4孢子浓度梯度标准土样,采用MoBio土壤基因组DNA提取试剂盒提取总DNA,以各FOC4孢子浓度梯度(1.66×10~3~1.66×108)的标准土样所提取的总DNA为模板进行实时荧光定量PCR,测定各标准土样中FOC4数量。以标准土样FOC4线性片段基因拷贝数的结果与FOC4线性片段基因100%提取率时的理论拷贝数的比值作为该标准土样FOC4基因组的提取率,对待检测土样FOC4的定量检测值进行校正,建立了一套较准确检测土壤FOC4数量的实时荧光定量PCR技术,其检测下线可达400个孢子/克土。应用该项技术对南天黄品种蕉园10个枯萎病病株的土样和10个未发病植株的土样和巴西蕉园5个发病植株的土样进行实际定量检测。结果表明,南天黄发病植株、未发病植株和巴西蕉发病植株的土样中FOC4的数量分别为每克土5 100~11 000个孢子/克土,3 500~7 800个孢子/克土和11 800~101 000个孢子/克土。本研究可准确检测土壤中的FOC4含量,同时也为香蕉枯萎病的防控措施的制定提供了帮助。

摘要：在室内测定菌株B215对香蕉枯萎病菌菌丝生长和孢子萌发都有良好抑制效果的基础上,优化拮抗菌株的最佳培养条件为:在NA培养基上,装液量为50mL/500mL,最适初始pH值为7.0～7.5,初始接菌量为1%,培养温度为28℃,以便更好地应用于田间试验。以此培养条件为依据,开展拮抗菌株的盆栽小苗实验,选用正交试验L8(27)设计,得出菌株B215对香蕉枯萎病菌的最佳防效组合为:在小苗定植前,用活菌培养液750mL/株浸根,可以降低小区香蕉枯萎病发病率。进一步试验验证结果显示:盆栽试验B215对Foc的防效为62.95%。