小麦根系分泌物对黄瓜生长及土壤真菌群落结构的影响

以黄瓜为受体，以不同化感效应(促进/抑制)小麦品种为供体，采用PCR-DGGE技术，研究了小麦根系分泌物及伴生小麦对黄瓜生长及土壤真菌群落结构的影响.结果表明： 在处理第6天和第12天，化感促进效应小麦根系分泌物分别显著提高了黄瓜幼苗株高和茎粗；在处理第18天，化感促进和抑制效应小麦根系分泌物均显著提高了黄瓜幼苗株高；在处理第6天，不同化感效应小麦根系分泌物均显著降低了黄瓜幼苗根际土壤真菌群落条带数、Shannon指数及均匀度指数,有苗对照(W)显著高于无苗对照(Wn)；在处理第18天，各处理的真菌群落结构条带数、Shannon指数及均匀度指数均显著高于无苗对照(Wn).伴生化感抑制效应小麦显著降低了黄瓜根际土壤真菌群落Shannon指数和均匀度指数，说明小麦根系分泌物及伴生小麦改变了土壤真菌群落结构.DGGE图谱及其主成分分析结果表明，伴生不同化感效应小麦对土壤真菌群落结构影响较大.

Effects of wheat root exudates on cucumber growth and soil fungal community structure.

With wheat as the donor plant and cucumber as the receptor plant, this study investigated the effects of root exudates from wheat cultivars with different allelopathic potentials (positive or negative) and companion cropping with wheat on soil fungal community structure by PCR-DGGE method and cucumber growth. Results showed that the wheat root exudates with positive allelopathic potential increased height and stem diameter of cucumber seedlings significantly, compared to the control seedlings (W) after 6 days and 12 days treatment, respectively. Also, wheat root exudates with both positive and negative allelopathic potential increased the seedling height of cucumber significantly after 18 days treatment. The wheat root exudates with different allelopathic potentials decreased the band number, Shannon and evenness indices of soil fungal community significantly in cucumber seedling rhizosphere, and those in the soil with the control seedlings (W) were also significantly higher than that in the control soil without seedlings (Wn) after 6 days treatment. The band number, Shannon and evenness indices in all the treatments were significantly higher than those in the control soil without seedlings (Wn) after 18 days treatment. Companion cropping with negative allelopathic potential wheat decreased the Shannon and evenness indices of soil fungi community significantly in the cucumber seedling rhizosphere, suggesting the wheat root exudates and companion cropping with wheat changed soil fungal community structure in the cucumber seedling rhizosphere. The results of DGGE map and the principal component analysis showed that companion cropping with wheat cultivars with different allelopathic potentials changed soil fungal community structure in cucumber seedling rhizosphere.