大豆根内胞囊线虫的时空动态研究

于2006—2007年田间自然生长条件下，研究大豆苗期(7~37 d)胞囊线虫(4号生理小种)在根系的时空分布动态。结果表明，大豆胞囊线虫分布与根系生长状况有密切关系。出苗后7 d已有线虫侵入根内，随着根系生长发育，单位根长线虫数以及线虫总数增多，单位根长内线虫数量呈S型曲线变化。随着出苗后天数的增加，主根和侧根内线虫数量变化呈相反趋势，其中主根内线虫密度减少，侧根内线虫密度增加至相对稳定值。随着土层的加深，主根和侧根内线虫密度差异减小；5~15 cm土层根系内线虫数量及其所占比例均最大。说明苗期大豆胞囊线虫主要分布在5~15 cm土层。

Space-Time Dynamics of Heterodera glycines in Soybean Roots

Population of Heterodera glycines fluctuations in the fields during growth of soybean. In order to investigate dynamics of Heterodera glycines in soybean roots, and provide more information of effective control for soybean cyst nematode, distribution and dynamics of soybean cyst nematode (SCN, Heterodera glycines, race 4) in the soybean roots were monitored during the period of 7–37 d after seedling emergence in 2006 and 2007. The results indicated that distribution of SCN population closely related to the growth of roots. Nematodes invaded the roots at 7 days after seedling emergence, and nematode density and population increased with the growth of soybean roots, the fluctuation of nematodes per centimeter root showed a sigmoid curve. The changed of nematodes per cm root showed an inverse trend with the age of seedlings between taproot and lateral root. Nematode density in taproot had a declining trend, when that in lateral root increased to a stable value. Difference of nematode density between taproot and lateral root decreased with deepening the soil layer, number of nematodes per cm root and percent to total nematodes reached the ultimate number in the 5–15 cm soil, suggesting that most of the nematodes distributed in lateral root and at the 5–15 cm soil layer during the soybean seedling stage.