根结线虫接种对黄瓜植株根际土壤pH和微生物的影响

通过人工接种不同数量的根结线虫卵,测定了黄瓜植株根际土壤的pH和微生物数量。结果表明,随接种数量的增加,根际土壤好气性细菌数量、厌气性细菌数量、细菌总数及细菌/真菌(B/F)逐渐降低;真菌数量却逐渐升高;放线菌数量在接种量为2000个·株-1时显著升高,之后随着接种量的增加逐渐降低;放线菌/真菌(A/F)在接种量为2000个·株-1时略有升高,之后随着接种量的增加逐渐降低。接种根结线虫后,黄瓜植株根际土壤中好气性细菌数量和B/F值与pH呈显著正相关,厌气性细菌数量、细菌总数、放线菌数量以及A/F值与pH呈极显著正相关,真菌数量与pH呈显著负相关。根结线虫侵染黄瓜植株导致根际土壤发生"真菌化",显示土壤质量下降。

Effect of root-knot nematode inoculation on rhizospheric soil pH and microbial community of cucumber (Cucumis sativus L. ) plant

Root-knot nematodes (RKNs) are the most destructive field pathogens of cucumber plant. This study evaluated rhizospheric soil pH and soil microbial community response to RKN inoculation. Results of the study show that aerobic bacteria, anaerobic bacteria and total bacteria number as well as bacteria/fungi (B/F) ratio gradually decline with the increasing inoculation rate. However, fungi number gradually increases with increasing inoculation rate. Both actinomyce/fungi (A/F) ratio and actinomyce number increase at an inoculation rate of 2 000 eggs per plant, but gradually decrease with increasing inoculation rate. Under RNKs inoculation, rhizospheric soil pH is significantly positively correlated with aerobic bacteria, B/F, anaerobic bacteria number, total bacteria number, actinomyce number and A/F ratio. However, rhizospheric soil pH is significantly negatively correlated with fungi number. RKNs infection apparently increases fungal population density in rhizospheric soils, implying degradation of soil quality due to RKNs infection.