【摘要】 为明确引起花卉铁筷子叶枯病的病原菌种类，采集具典型症状的叶片与花朵，经组织分离、致病性测定、形态观察与分子生物学鉴定，确定病原为链格孢[Alternaria alternata（Fr.） Keissl.]，这是首次发现该菌为害铁筷子。通过测定不同培养基、温度、pH、碳源、氮源培养条件下病原菌的菌落直径，探索该菌的生长规律，并采用菌丝生长速率法测定不同杀菌剂对该菌的室内毒力。结果表明，最适宜菌丝生长的温度为25～30℃，高于35℃时菌丝生长缓慢；病原菌在pH为4～11的条件下均能生长，且无明显差异；最适培养基为PDA，葡萄糖为最佳碳源，酵母粉或蛋白胨为最佳氮源。该病原菌对咪鲜胺和异菌脲的敏感性较高，EC₅₀<0.5 mg/L。研究结果可为铁筷子叶枯病的防治提供理论依据。更多还原

【Abstract】 The present study was conducted with the objective of c larifying the pathogen species causing leaf blight disease in Helleborus × hybrids. To this end, leaves and flowers with typical symptoms of the disease were collected for further analysis. By means of tissue isolation, pathogenicity determination, morphological observation, and molecular biological identification, the pathogen was identified as Alternaria alternata（Fr.） Keissl. This marked the first documented instance of the pathogen damaging Helleborus × hybrids. The growth pattern of the pathogen was explored by measuring the colony diameter of the pathogen in various conditions, including different culture media, temperatures, pH levels,carbon sources, and nitrogen sources. The indoor toxicity of different fungicides to the pathogen was determined by measuring the mycelium growth rate. The results showed that the optimum temperature for mycelial growth was between 25 and 30 ℃, with growth being hindered at temperatures exceeding 35 ℃. The pathogen demonstrated the capacity to grow under conditions of pH 4-11, exhibiting no significant variation. The optimal medium for mycelial growth was PDA, while glucose and yeast powder or peptone were identified as the most effective carbon and nitrogen sources, respectively. The pathogen was highly sensitive to prochloraz and iprodione, with EC₅₀ values below 0.5 mg/L. The research results can serve as a theoretical basis for the prevention and control of leaf blight in Helleborus × hybrids.更多还原