连作对不同抗性芝麻根系分泌物中酚酸类物质含量的影响及其化感作用

Effects of Continuous Cropping on Contents of Phenolic Acids in Root Exudates of Different Resistant Sesame Varieties and Their Allelopathy

通过对芝麻花期根系分泌物中酚酸类物质含量在正茬和连作条件下的变化及其自毒作用的研究,初步探讨了3个不同连作抗性芝麻品种根系分泌物中具有化感作用的酚酸类物质。结果表明:水杨酸、柠檬酸和对羟基苯甲酸在3个芝麻品种根系分泌物中含量均较高;苯丙酸、苯甲酸和香豆酸分别在赣芝9号、金黄麻和玉山黑芝麻根系分泌物中含量也较高。与正茬条件下相比,在连作条件下,赣芝9号根系分泌物新检测到香草酸,金黄麻和玉山黑芝麻根系分泌物均新检测到丁香酸和苯丙酸;赣芝9号根系分泌物中柠檬酸、香豆酸、苯甲酸和丁香酸含量显著上升,金黄麻根系分泌物中水杨酸、对羟基苯甲酸、绿原酸、香草酸、柠檬酸、苯甲酸和香豆酸含量显著升高,玉山黑芝麻根系分泌物中阿魏酸、苯甲酸、水杨酸和绿原酸含量显著升高。对酚酸类物质的自毒作用进行生物检测,发现绝大多数酚酸对芝麻发芽表现出“低促高抑”现象。结合酚酸类物质在芝麻根系分泌物中的含量,认为香豆酸、柠檬酸和丁香酸是导致赣芝9号连作障碍的化感物质,苯丙酸、苯甲酸、水杨酸和丁香酸是导致金黄麻连作障碍的化感物质,水杨酸、苯丙酸和丁香酸是导致玉山黑芝麻连作障碍的化感物质。

Root exudates at flowering stage were collected from 3 different continuous cropping resistant sesame varieties,and the contents of phenolic acids under normal rotation(CK)and continuous cropping as well as their allelopathy were analyzed.Re?sults showed that salicylic acid,citric acid and p-Hydroxybenzoic acid were the main component in 3 sesame varieties.Except for these three phenolic acids,3-phenylpropionic acid,benzoic acid and coumalic acid was the other main component in Ganzhi 9,Jinhuangma and Yushanhei,respectively.Compared with CK,vanilic acid was newly tested in Ganzhi 9 under continuous crop?ping,while syringic acid and 3-phenylpropionic acid were both newly tested in Jinhuangma and Yushanhei.The contents of citric acid,coumalic acid,benzoic acid and syringic acid in root exudate in Ganzhi 9 under continuous cropping increased significantly.The contents of salicylic acid,p-Hydroxybenzoic acid,chlorogenic acid,vanilic acid,citric acid,benzoic acid and coumalic acid in root exudate in Jinhuangma increased significantly.The contents of ferulic acid,benzoic acid,salicylic acid and chlorogen?ic acid in root exudate in Yushanhei increased significantly.The allelopathy of phenolic acids was tested by investigating germina?tion indexes of 3 sesame varieties.Most phenolic acids showed that low concentration can promote sesame germination,and high concentration showed contrary effect.Coumalic acid,citric acid and syringic acid were the allelochemicals affected continuous cropping of Ganzhi 9.3-phenylpropionic acid,benzoic acid,salicylic acid and syringic acid were the allelochemicals in Jinhuang?ma.Salicylic acid,3-phenylpropionic acid and syringic acid were the allelochemicals in Yushanhei.