伴生杂草提取液对花椒根腐病菌的抑菌活性

Screening of the antibacterial activity of accompanying weed extracts against Fusarium solani

为探明伴生杂草的抑菌作用及其在土传病害生物防治中的应用价值,通过样方调查分析花椒伴生杂草的种类和群落结构,采用生长速率法测定研究优势伴生杂草对花椒根腐病病原菌的抑制情况.结果表明:20种伴生杂草的水提取液均能促进腐皮镰孢菌生长,其中地蚕、刺儿菜、粗毛牛膝菊、繁缕、灰菜、圆叶锦葵、香薷、苦苣菜、欧洲千里光、猪殃殃、蒲公英和野苜蓿具有显著(P<0.05)促进作用,促进率在6.22%-16.61%之间;而地钱、黄花蒿、菊叶香藜、老鹳草、覆盆子和羽叶蓼这6种杂草的甲醇提取液能显著(P<0.05)抑制腐皮镰孢菌的生长且存在明显浓度效应,抑制强度表现为地钱>黄花蒿>菊叶香藜>老鹳草>覆盆子>羽叶蓼,培养3 d、4 d、5 d的抑菌率依次在17.5%-53.0%、16.2%-54.0%、15.9%-53.2%之间.可见,伴生杂草不仅通过资源竞争抑制花椒生长,还通过化感作用促进根腐病病原菌生长,是雨后椒园根腐病频发的原因之一;筛选出地钱、黄花蒿、老鹳草和菊叶香藜的甲醇提取液中含有抑菌活性物质,进一步开发植物源杀菌剂防治花椒根腐病提供了一定理论基础.

The root rot of Zanthoxylum bungeanum has continued to occur in Maoxian County in southwestern China,resulting in the death of a large number of adult pepper trees.Consequently,the yield of Z.bungeanum has fallen sharply.To date,no effective treatments for the disease have been identified.This study aimed to reveal the relationship between Z.bungeanum associated weeds and soil-borne diseases and to screen for plant species that have inhibitory activity against root rot pathogens,which will help generate new ideas for the biological control of root rot.In this study,the species composition of weeds in the Z.bungeanum garden were analyzed through community surveys to identify the dominant weeds.The growth rate method was used to determine the inhibition rate of dominant weeds against Fusarium solani,which is the main pathogen causing root rot in Z.bungeanum.The water extracts of 20 associated weeds promoted the growth of Fusarium solan.Among these,Stachys geobombycis,Cirsium setosum,Galinsoga quadriradiata,Stellaria media,Chenopodium album,Malva rotundifolia,Elsholtzia ciliata,Sonchus oleraceus,Senecio vulgaris,Galium aparine,Taraxacum mongolicum,and Medicago falcate significantly(P<0.05)promoted pathogen growth with promotion rates between 6.22%and 16.61%.However,the methanol extracts of six weeds(Marchantia polymorpha,Artemisia annua,Chenopodium foetidum,Geranium wilfordii,Rubus idaeus,and Polygonum runcinatum)inhibited the growth of Fusarium solani significantly(P<0.05).The inhibition intensities were ranked as follows:Marchantia polymorpha>Artemisia annua>Chenopodium foetidum>Geranium wilfordii>Rubus idaeus>Polygonum runcinatum.The inhibitory rates following culture for 3,4,and 5 d ranged 17.5%–53.0%,16.2%–54.0%,and 15.9%–53.2%,respectively.In conclusion,associated weeds may inhibit the growth of Z.bungeanum through resource competition and growth promotion of Fusarium solani through allelopathic effects,which is one of the reasons for the frequent occurrence of root rot in pepper gardens after rain.This study identified that the methanol extracts of Marchantia polymorpha,Artemisia annua,Chenopodium foetidum,and Geranium wilfordii contain antibacterial substances,providing a theoretical basis for further development of plant-derived fungicides and prevention and control of Z.bungeanum root rot.