连作大豆根分泌物对根腐病病原菌的化感作用

采用砂培，水培和室内培养等试验方法研究了连作大豆根分泌物对根腐病病原菌的化感作用。结果表明，与对照相比，连作和轮作大豆根分泌物对半镰孢菌，粉红粘帚功和尖镰孢菌尤其是对半裸镰孢菌的生长有明显的化感促进作用，差异达显著或极显著水平，低浓度时，连作大豆根分泌物对半裸镰孢菌和粉红粘帚菌生长的化感促进作用明显大于轮作大豆，差异达显著水平，同一茬口，高浓度根分泌物半裸镰孢菌生长的化感促进作用小于低浓度，而且在连作大豆中差异达显著水平。与对照相比，高浓度的邻苯二甲酸和丙二酸（L5和B5）对半裸镰孢菌，粉红粘帚菌和尖镰孢菌尤其是对半裸镰孢菌的生长有化感抑制作用，差异达显著或极显著水平，而低浓诬的邻苯二甲酸和丙二酸对半裸镰孢菌，粉红粘帚菌和尖镰孢菌的生长有化感促进,部分差异达显著水平。

Allelopathic effect of root exudates on pathogenic fungi of root rot in continuous cropping soybean

Allelopathic effect of root exudates on pathogenic fungi of root rot in continuous cropping soybean was studied by sand culture, water culture, and indoor culture experiments. The results showed that allelopathic promotion of root exudates on the growth of Fusarium semitectum, Gliocladium roseum and Fusarium oxysporum, especially Fusarium semitectum reached significant level or especially significant level in continuous cropping soybean compared with the control. Allelopathic promotion of root exudates on the growth of Fusarium semitectum and Gliocladium roseum in continuous cropping soybean was distinctly larger than that in rotation soybean, and the difference reached significant level under their low concentration. Allelopathic promotion of high concentration of root exudates on the growth of Fusarium semitectum was smaller than that of low concentration of root exudates, and the difference reached significant level in continuous cropping soybean. Allelopathic inhibition of high concentration of phthalic acid and propanedioic acid (L 5 and B 5) on the growth of Fusarium semitectum, Gliocladium roseum and Fusarium oxysporum, especially Fusarium semitectum reached significant level or especially significant level compared with the control. However, allelopathic promotion of low concentration of phthalic acid and propanedioic acid on the growth of Fusarium semitectum, Gliocladium roseum and Fusarium oxysporum partly reached significant level.