根腐病对党参细胞结构和生理特性的影响

为明确党参（Codonpsis pliosula）被尖孢镰孢菌（Fusarium oxysporiums）侵染后其叶片细胞结构和生理特性的变化，本试验以‘渭党1号’为研究材料，通过田间自然发病测定病原菌侵染后党参根部细胞结构以及生理特性的变化特征。叶片显微镜观察结果表明，健康党参叶片呈深绿色，发病叶片呈黄绿或黄白交替症状，透光性增强；根部徒手切片光学显微镜观察结果表明，发病部位细胞受到严重破坏；发病党参叶片叶绿素含量降低，电解质渗漏电导率升高。镰孢菌侵染后，发病党参叶片的净光合速率、气孔导度、胞间CO₂浓度和蒸腾速率降低；发病党参的最大净光合速率、光饱和点和暗呼吸速率均降低，而光补偿点升高；发病党参CO₂饱和点降低，而CO₂补偿点和光呼吸速率升高。发病党参植株叶片氮、磷、钾和锌、锰、铜、铁、钙、镁等一些微量元素的含量也降低。本研究从宏观和微观角度分析了镰孢菌侵染后党参细胞结构和生理特性的变化，为阐明党参根腐病的发病机制提供了理论依据。

Effects of Fusarium oxysporiums on the Cell Structure and Physiological Characteristics of Codonopsis pilosula

In order to clarify the effects of leaf cell structure,physiological characteristics on Codonopsis pilosula infected with Fusarium oxysporiums,we used variety ‘Weidang No.1’ as plant material tested relative parameters in field experiment under a natural diseased condition. Microscopic observation showed that the normal plant leaves color was in dark-green,while the sick-leaves exhibited a alternating symptom of yellow-green or yellow-white,and also the light transmittance increased finally. Microscopic observation of hand-cut section revealed that the cell structure of the diseased roots was seriously damaged,chlorophyll content in sick-leaves was decreased,while the electrolyte leakage conductivity was increased. Compared to the control,photosynthetic rates,the stomatal conductance,transpiration rate and the concentrations of intercellular CO₂ were decreased. Moreover,compared to the control,the light saturation point,maximum net photosynthetic rate and the dark respiration rate were decreased,while the light compensation point was increased. In addition,CO₂ saturation point was decreased,whereas the CO₂ compensation point and the light respiration rate were increased. The content of Nitrogen,Phosphorus,Potassium and some nutrient elements including Zn,Mn,Cu,Fe,Ca,Mg was decreased. Our results provide a theoretical basis for elucidating the pathological mechanism of Codonopsis pilosula root rot disease.