【摘要】 为研究山新杨白粉病的病原菌种类以及病原菌侵染后宿主叶片的生理反应，观察了山新杨白粉病菌分生孢子的形态特征及特异性入侵结构，统计不同介质分生孢子的萌发情况，测定5个不同感病时期(健康、早期、中期、晚期、末期)山新杨叶片的过氧化氢酶(CAT)、过氧化物酶(POD)、超氧化物歧化酶(SOD)活性和丙二醛(MDA)的质量摩尔浓度变化，应用分子生物学分析的方法鉴定山新杨白粉菌病原。结果表明：山新杨白粉病菌分生孢子萌发时产生裂瓣状附着胞，并且萌发时不受介质面影响。感病前后，山新杨叶片内的生理生化指标变化显著，其中超氧化物歧化酶、过氧化物酶以及过氧化氢酶活性均呈先升高后下降趋势，丙二醛质量摩尔浓度则呈不断上升趋势。说明侵染前期，由于白粉病菌胁迫，叶片活性氧上升，抗氧化酶活性与丙二醛质量摩尔浓度升高；随着感病程度加重，叶片清除活性氧的能力下降，抗氧化酶活性降低，丙二醛质量摩尔浓度升高。通过ITS序列比对与系统发育进化树分析，可认为山新杨白粉病病原菌为Erysiphe adunca(Wallr.) Fr. var.adunca。更多还原

【Abstract】 To study the pathogenic fungal species of powdery mildew on Populus davidiana×P. bolleana and the physiological responses of host leaves after pathogen infection, the morphological characteristics and specific invasion structures of the conidia of powdery mildew on P. davidiana×P. bolleana were observed. The germination situation of conidia in different media was recorded, and the changes in catalase(CAT), peroxidase(POD), superoxide dismutase(SOD) activities, and malondialdehyde(MDA) molar concentration in P. davidiana×P. bolleana leaves at five different disease stages(healthy, early, middle, late, and final stages) were determined. The pathogen of powdery mildew on P. davidiana×P. bolleana was identified through molecular biology analysis. The results showed that conidia of powdery mildew on P. davidiana×P. bolleana produced lobed appressoria during germination, and their germination was not affected by the medium surface. Before and after infection, significant changes occurred in the physiological and biochemical indicators in P. davidiana×P. bolleana leaves. Superoxide dismutase, peroxidase, and catalase activities showed an initial increase followed by a decrease, while the molar concentration of malondialdehyde continued to rise. This indicates that during the early stages of infection, leaf reactive oxygen species increased due to powdery mildew pathogen stress, leading to increased antioxidant enzyme activity and malondialdehyde concentration. As the disease progressed, the leaf’s ability to remove reactive oxygen species decreased, antioxidant enzyme activity decreased, and malondialdehyde concentration increased. Based on ITS sequence alignment and phylogenetic tree analysis, the powdery mildew pathogen on P. davidiana×P. bolleana was identified as Erysiphe adunca(Wallr.) Fr. var. adunca.更多还原