牡丹皮乙醇提取物对黄瓜枯萎病菌的活性抑制及作用机制

Inhibitory Activity and Mechanism of Ethanol Extract of Moutan Bark on Fusarium oxysporum f.sp.Cucumerinum Causing Fusarium Wilt of Cucumber

为探究牡丹皮对黄瓜枯萎病菌(Fusarium oxysporum f.sp.cucumerinum)的抑菌活性,通过用不同浓度的牡丹皮乙醇提取物处理黄瓜枯萎病菌,测定其对枯萎病菌的菌丝生长抑制率、胞外电导率、A260 nm与A280 nm的变化,使用光学显微镜观察处理后的菌丝形态变化。结果表明:牡丹皮乙醇提取物处理后的黄瓜枯萎病菌胞外电导率、A260 nm和A280 nm显著上升,菌丝出现膨胀畸变等现象;其中质量浓度为25.0 mg/mL的牡丹皮乙醇提取物可显著降低黄瓜枯萎病菌的生长速度,处理48 h后抑菌率可达到92.08%;进一步研究认为,牡丹皮通过破坏黄瓜枯萎病菌的细胞膜结构,使胞内物质渗出,造成菌丝形态结构畸变,进而抑制了菌体细胞的生长与繁殖。

In order to explore the inhibitory activity of Moutan Cortex on Fusarium oxysporum f.sp.cucumerinum,in this experiment the different concentrations of Moutan Cortex ethanol extract was used to treat F.oxysporum f.sp.cucumerinum,and its mycelial growth inhibition rate,extracellular conductivity,A260 nm and A280 nm changes of F.oxysporum f.sp.cucumerinum were determined and the morphological changes of the treated mycelium were observed under optical microscope.The results showed that the extracellular conductivity,A260 nm and A280 nm of F.oxysporum f.sp.cucumerinum treated with ethanol extract of Moutan Cortex increased significantly.The hyphae of F.oxysporum f.sp.cucumerinum treated with ethanol extract of peony bark showed swelling and distortion.The ethanol extract of Moutan Cortex with mass concentration of 25.0 mg/mL could significantly reduce the growth rate of F.oxysporum f.sp.cucumerinum,and the inhibition rate could reach 92.08%after 48 h of treatment.Therefore,Moutan Cortex could destroy the cell membrane structure of F.oxysporum f.sp.cucumerinum,resulting in exudatio of intracellular substances,distortion of mycelial morphology,and then inhibition of the growth and reproduction of pathogen cells.