中文摘要：

运用涂布平板法从健康豆娘肠道中分离得到1株真菌DN02，采用形态学和ITS序列分析方法对其进行了鉴定，用生长速率法及盆栽试验测定其除草活性，利用色谱方法从该菌乙酸乙酯粗提物中分离出活性物质，并采用质谱和核磁共振谱对活性物质结构进行鉴定。结果表明DN02为新月旋孢腔菌Cochliobolus lunatus；其乙酸乙酯粗提物对稗草和反枝苋具有较强的抑制活性，对幼根抑制活性的IC50分别为22.9 μg/mL和136.7 μg/mL；当喷施发酵液原液时，稗草受害率、平均株高、平均鲜重分别为66.7%、5.2 cm、13.8 mg，其效果与阳性对照2，4-二氯苯氧乙酸相当；并于乙酸乙酯粗提物中分离得到一个单体活性物质根匍柄菌素（radicinin）。

英文摘要：

A fungus named DN02 was isolated from the gut of Ceriagrion sp. by means of spread plate. DN02 was identified according to morphological characteristics and ITS sequence analysis. The herbicidal activity experiment was performed by growth rate method and sprayed with fermentation broth of DN02. The main active compound was isolated by using column chromatography and identified on the basis of extensive spectroscopic analysis. The results showed that DN02 was Cochliobolus lunatus;ethyl acetate extract exhibited significant phytotoxic activities against the radicle growth of Echinochloa crusgalli and Amaranthus retroflexus with IC50 values of 22.9 μg/mL and 136.7 μg/mL, respectively. When sprayed with fermentation broth of DN02, the victimization rate, average plant height and fresh weight of E.crusgalli were 66.7%, 5.2 cm, and 13.8 mg, respectively, comparable to the positive control 2, 4-D （2, 4-（dichlorobenzene） acetic acid）. The crude extract contained a main active compound and it was determined as radicinin. The results suggest that further researches are needed for C.lunatus DN02 as a microbial herbicide.