胜红蓟黄酮类物质对柑桔园主要病原菌的抑制作用

柑桔园引种杂草胜红蓟能有效地控制主要病害，研究发现，胜红蓟产生并释放到土壤中的黄桐类物质对疮痂病菌、炭疽病菌、白粉病菌和烟煤病菌等柑桔园主要病原真菌具有抑制活性，从胜红蓟植株中分离鉴定了10个黄酮物质，包括一个糖甙黄酮分子，但胜红蓟植株产生的大部分黄酮物质在土壤中会逐渐降解，只有3个黄酮分子能在柑梧园的土壤中累积并存在较长时间，而这3个黄酮物质对柑桔园主要病原真菌具有显著的抑制活性，其活性不仅超过胜红蓟释放的其化感物质，而且强于商业的杀菌剂多菌灵，表明胜红蓟产生和释放的黄酮物质在柑桔园病害控制中起着重要作用。

Inhibitory effect of flavones from Ageratum conyzoides on the major pathogens in citrus orchard

Inter-cropping with Ageratum conyzoides may effectively control major pathogens in citrus orchard. The research showed that flavones produced by and released from A. conyzoides could inhibit the major fungal pathogens,such as Elsimoe fawcetti Bit. Et Jenk, Collelotrichum gloeosporimdes Penz, Oidium tingitaninum Carter, Capondium citri Berk et Desm in citrus orchard. 10 flavones,including one glycoside,from A. conyzoides plant were isolated and identified. Most of them could gradually degraded in soil and only 3 flavones could be accumulated and last a long time. Just these 3 flavones could obviously possess inhibitory effect on fungal pathogens in citrus orchard. The inhibitory effect of the 3 flavones was stronger,not only than those of other allelochemicals produced by and released from A.conyzoides ,but also than that of Carbenzin,a commercial fungicide. Therefore,the flavones produced by and released from A.conyzoides played an important role in pathogens control in citrus orchard.