假隔链格孢SF-193的产孢特性及其分生孢子对空心莲子草的致病力

Conidial Production of Nimbya alternantherae SF-193 and Its Pathogenicity to Alternanthera philoxeroides

为了探明SF-193的产孢特性,选取了8种产孢培养基,研究分别在自然光、黑光灯和黑暗的条件下对SF-193产孢的影响程度。试验结果表明,在黑光灯连续照射11d后,SF-193在PCA、CA、SNA、Czapek和组织煎汁5种培养基上有少量分生孢子产生,而在其他3种琼脂培养基上不产生分生孢子。PCA培养基中马铃薯与胡萝卜比例为1：5时,SF-193在9d后产孢量最大,10×10倍显微观察约60个孢子/视野;当CA培养基中的胡萝卜含量提高至80%左右时, SF-193在3d后达到最大产孢量,10×10倍显微观察约300个孢子/视野。研究了黑光灯照度与胡萝卜含量对SF-193产孢的影响。结果表明,在黑光灯照度为195～210lx、胡萝卜含量约为0.8g/ml时,SF-193在25℃培养6d后产孢量最大,约为6.5×10^5个孢子/ml。SF-193的分生孢子在田间对空心莲子草的致病力测定结果表明,经孢子浓度10^4个孢子/ml处理后,空心莲子草的病情指数为67.7。

Nimbya alternantherae SF-193 was cultured on agar plates of eight media at 25℃under nature light,black light lamp and dark,respectively,for understanding its conidial production.The results showed that a few of conidia was produced on PCA,CA,SNA,Czapek and filtrate of the alligator weed under light from black light lamp for 11 d.And under natural light and dark,SF-193 could not produce conidia on these mediums.The maximum conidia yield was obtained on the PCA in irradiation of black light for 9 d when the proportion of potato and carrot was 1：5,and about 60 conidia were observed under magnification 10×10.However,about 300 conidia were observed on the medium of CA in irradiation of black light lamp for 3 d when the carrot content was increased to 80%.The intensity of illumination of the black light and carrot content could strongly influence conidia yield of SF-193.When the intensity of illumination of the black light lamp was about 195-210 lx and the carrot content of CA medium was increased to 80%,the amount of conidia was more than 6.5×10^5 conidia/ml after culturing for 6 d at 25℃.The pathogenicity of conidia to Alternanthera philoxeroides was tested in the field and the disease index of the weed was about 67.7.