酚酸类化感物质对两种西洋参病原真菌的作用

采用室内菌丝生长抑制实验,选择土壤与植物体内常见的酚酸类化合物香草酸、丁香酸、阿魏酸和香豆酸并根据它们在西洋参种植地土壤中的含量设计测试浓度,测定这些化感物质对西洋参致病菌立枯丝核菌(Rhizoctonia solani)、根腐菌(Fusarium solani)菌丝生长的作用,探讨酚酸类化感物质与西洋参病原菌之间的关系.试验结果显示:浓度为0.1～1 mmol/L的丁香酸对西洋参立枯丝核菌菌丝生长具有促进作用,香草酸也有一定的促进作用,但不呈浓度效应,浓度在1 mmol/L以上的香豆酸对其有显著的抑制作用,阿魏酸也有一定抑制作用;对于西洋参根腐菌,阿魏酸对其生长有明显促进作用,香豆酸也有一定促进作用,香草酸表现为低浓度促进,高浓度抑制作用,0.1～1 mmol/L丁香酸对其生长基本无影响.不同酚酸在不同浓度下对2种西洋参病原菌作用不同,在田问实际情况下,化感酚酸与西洋参病害的发生之间可能是一种复杂的过程.

Effects of Phenolic Allelochemicals on the Pathogen of Panax quiquefolium L.

Phenolic allelochemicals such as vanillic acid, syringic acid, ferulic acid and p-coumaric acid, have been proved to be autotoxins produced by Panax quiquefolium.L. In order to elucidate the interaction between the autotoxins and the disease occurence in ginseng fields, we investgated the effects of the four phenolic acids on the mycilum growth of two pathogens isolated from ginseng and the fields. The mycelial growth of Rhizoctonia solani was promoted by vanillic acid and syringic acid at levels of 0.1~1 mM/L, and it was inhibited remarkably by p-counaric acid of over 1mM/L and modestly by ferulic acid. The radial extent of mycelia of Fusarium solani was increased significantly by ferulic acid of 0.1~1 mM/L and limitedly by p-coumaric acid. vanillic acid had paradoxcial effects on the growth, positively at low levels and negtively at high levels, on which Syringic acid had a slight effect. It is concluded that various phenolic acids had irregular effects on the growth of the pathogens at different concentrations, and there is a complicated relationship between the autotoxins and the occurrence of disease in the ginseng field.