五倍子抑制番茄晚疫病原菌物质的提取分离与作用机理初步分析

以致病疫霉番茄晚疫病原菌为供试菌,研究五倍子水提物及其分离纯化物的抑菌机制。对五倍子粗提液醇沉萃取物进行抑菌实验与结构解析,并在后期通过扫描电镜与透射电镜观察,结合电导率判定其抑菌机制。研究结果显示,乙酸乙酯萃取相抑菌圈直径为(33.9±0.4)mm,显著(P<0.05)高于其它各萃取相。对乙酸乙酯萃取相进行柱层色谱分离,得到一组抑菌圈直径达(36±0.2)mm的单体流分,显著(P<0.05)高于其它各组流分;对此单体流分进行二次柱层色谱分离,得到抑菌圈直径达(37.3±0.2)mm的单体,结构鉴定显示为鞣酸。扫描电镜与透射电镜观察显示,五倍子鞣酸能使番茄晚疫病原菌孢子表面凹陷,边缘轮廓清晰性下降,内核皱缩显著,对孢子结构造成一定破坏。五倍子鞣酸能改变番茄晚疫病原菌的细胞膜通透性,其作用效果与浓度有关,浓度越大作用效果越好。

Extraction and Isolation of Nutgall Against Pathogenic Bacteria of Tomato Late Pathogen and Preliminary Analysis of Its Mechanism

In this study,the pathogenic bacteria of tomato late pathogen was used as the test bacteria to study the mechanism of action of crude extract and purification of nutgall. Extraction,separation and structure analysis of crude extract of nutgall were carried out,and the results were observed by SEM and TEM,determined the action mechanism by the conductivity measurement. The results showed that:The diameter of bacteriostatic zone of ethyl acetate extraction was(33.9±0.4) mm,which was significantly(P<0.05)higher than other parts. Then a group of monomer flow fraction with diameter of(36±0.2) mm was obtained by column chromatography of ethyl acetate extraction,which was significantly(P<0.05)higher than that of other groups. A monomer with a diameter of(37.3±0.2) mm was isolated by secondary column chromatography,and its structure was identified as tannic acid. The tannic acid against the pathogenic bacteria of tomato late pathogen was observed by SEM and TEM,the results showed that tannic acid from Chinese nutgall had dimpled the spore surface of the pathogenic bacteria of tomato late pathogen,the cell margins became less clear,the cell kernel was significantly shrunken,caused some damage to the cell structure. Tannic acid of Chinese nutgall could change the cell membrane permeability of pathogenic bacteria of tomato late pathogen,its effect was concerned in concentration,the higher of the concentration,the better effect the results would be.