香叶醇对柑橘酸腐病菌的抑菌机制

为研究香叶醇对柑橘酸腐病菌（Geotrichum citri-aurantii）的抑菌机制，用不同质量浓度的香叶醇处理柑橘酸腐病菌，通过生理生化分析及微观结构观察研究其对酸腐病菌孢子和菌丝体的影响。结果表明，香叶醇对柑橘酸腐病菌的最小抑菌质量浓度（minimal inhibitory concentration,MIC）和最小杀菌质量浓度（minimal fungicidal concentration,MFC）均为0.500 g/L;MIC香叶醇处理酸腐病菌12 h后其孢子萌发率仅为（3.28±1.28）%，显著低于对照组的（92.17±1.88）%(P<0.05)。透射电子显微镜观察发现，香叶醇处理破坏了酸腐病菌细胞的完整性，细胞壁与细胞膜发生质壁分离，细胞器无法分辨，呈现空泡化。细胞通透性发生改变，碱性磷酸酶和核酸发生外泄，相对电导率升高，膜脂质过氧化反应增强，活性氧积累。综上所述，香叶醇通过抑制柑橘酸腐病菌孢子萌发和菌丝生长、破坏细胞结构、促进脂质过氧化和活性氧积累从而影响其正常生理功能，本实验可为有效防治柑橘酸腐病提供新思路。

Inhibitory Mechanism of Geraniol against Geotrichum citri-aurantii in Citrus

In order to study the antifungal mechanism of geraniol on Geotrichum citri-aurantii, the effects of different concentrations of geraniol on the spores and mycelia of G. citri-aurantii were investigated by physicochemical analysis and microstructural observation. The results showed that the minimum inhibitory concentration (MIC) and minimum fugicide concentration (MFC) of geraniol against G. citri-aurantii were both 0.500 g/L. The spore germination rate of G. citri-aurantii treated with geraniol at MIC for 12 h was only (3.28 ± 1.28)%, which was significantly lower than that (92.17 ± 1.88)% in the control group (P < 0.05). Transmission rlectron microscope (TEM) showed that geraniol treatment destroyed the integrity of G. citri-aurantii cells, and led to separation between the cell wall and membrane, the organelles were indistinguishable, and the cells were vacuollated. The membrane permeability was altered, alkaline phosphatase (AKP) and nucleic acid was leaked out from the cells, the relative conductivity was increased, membrane lipid peroxidation was enhanced, and reactive oxygen species (ROS) were accumulated. In conclusion, geraniol affects the normal physiological function of G. citri-aurantii by inhibiting the spore germination and mycelial growth, disrupting the cellular structures, and promoting the accumulation of membrane lipid peroxidation and ROS, which provides a new idea for the effective control of G. citri-aurantii in citrus.