三唑酮对玉米弯孢病菌超微结构和细胞化学的影响

三唑酮(triadimenfon)属于麦角甾醇类生物合成抑制剂(ergosterol biosynthesis inhibitors．EBI),具有较广的抗真菌谱,明确其对玉米弯孢菌发育的影响可为该杀菌剂的田间应用提供理论依据。利用电镜技术和细胞化学技术观察的结果表明,玉米率孢菌经三唑酮处理后,菌丝生长明显受到抑制,表现为菌落生长速度减慢、菌丝分枝增多,且不观则地肿大和缢缩,出现许多瘤状突起,处理菌丝明显畸形。透射电镜观察结果表明,三唑酮可引起菌丝细胞壁不规则增厚,特别是菌丝顶端细胞壁增厚尤为明显:菌丝细胞隔膜发育受阴而表现畸形;菌丝细胞外有大量电子染色深的外渗物质。细胞化学标记定位结果表明,真菌细胞壁主要成分β-1,3-葡聚糖和几丁质的含量在药剂处理后发生很大变化,其标记密度明显低于未处理的对照菌丝,表明病菌细胞壁的结构和功能受到明显的不利影响。论文对弯孢菌受三唑酮影响后胞壁成份变化与其它真菌不同的原因进行了讨论。

Effects of fungicide triadimefon on development of Curvularia lunata in vitro

The effects of triadimefon1-(4-chlorophenoxy)-3,3-dimetyol-1-(1,2,4-triazol-l-yl)butan-2-one],a systemic fungicide from the triazol group were examined on morphology,structure,cell wall components of Curvularia lunata by means of electron microscopy and cytochemical labelling techniques.The studies revealed that triadimefon not only inhibited the hyphal growth but also caused a series of marked morphological and structural alterations of hyphae.These changes included irregular swelling,excessive branching,tumorous protuberance on the surface of hyphae,and considerable thickening of the hyphal cell walls,particularly at the hyphal tip region.The septum development of the hyphae was inhibited and became malformed.Dense electronic opaque material secreted by fungicide-treated hyphal cells was observed by TEM.Using cytochemical techniques,the labelling densities of chitin andβ-1,3-glucan on the cell wall of the fungicide-treated hyphae were decreased dramatically comparing with those of the control hyphae,indicating that the detrimental effects of the fungicide on structure and function of the hyphal membranes,and composition changes of the cell walls.The possible mechanism involved in mode of action of triadimefon against Curvularia lunata was discussed.