橡胶苗组培生产中一种污染菌粗糙脉孢霉的鉴定及防治

Abstract

组培技术应用是加快推广橡胶树良种化育苗的技术革命，具有显著降低育苗成本和改良橡胶树农艺性状等优点。然而，组培生产过程中杂菌污染是造成生产成本高的主要原因之一。本研究通过形态学和分子鉴定，发现在橡胶树组织培养生产中一种具有超强污染能力菌是粗糙脉孢霉。该真菌是一种很强的好氧菌，孢子萌发和菌丝生长速度极快，产孢能力强可以借助空气的传播，迅速扩大污染率，因而迫切需要筛选快速杀死它的菌剂。我们采用室内生长速率法测定了六种农药对粗糙脉孢霉的毒力，得到相关的独立回归方程及抑制中浓度。结果表明，40%福星乳油对粗糙脉孢霉菌的抑制效果最好，其EC50最小；其次为70%甲基托布津可湿性粉剂；50%扑海因可湿性粉剂，99%恶霉灵可湿性粉剂，50%敌磺钠可湿性粉剂对其的杀菌效果均一般，50%多菌灵可湿性粉剂无效。我们用500倍的敌磺钠处理污染橡胶苗后，发现挽救成功率可达94%。 Tissue culture technology is a major skill in fast promotion of new cultivars of rubber tree. However, fungi contamination has been a main cause which wasted more money in amount of seedling production. In this study, a fungus was identified as a super pollutant agent which rendered high rate of pollution in tissue culture of rubber tree. After morphology and molecular identification analysis, this fungus was confirmed to be Neurospora crassa, (N. crassa, for short). N. crassa was a highly aerobic fungi, grew fast and produced a large amount of spores, therefore fastened pollution in culture room. It rose to be an urgent issue to seek efficient fungicide. Here, six fungicides were compared with their abilities of inhibiting growth of N. crassa with indoor growth rate analysis. The independent regression equation and the EC50 value of inhibitory concentration were obtained. The results showed that 40% Fuxing EC had the best inhibitory effect on N. crassa, with the lowest EC50, followed by 70% Thiophanate-Methylwettable powder, 50% Rovral fluttering wettable powder, 99% hymexazol wettable Powder and 50% sodium sulfonate wettable powder with moderate effects. Unexpectedly, 50% carbendazim wettable powder was invalid at all. The survival rate of contaminated rubber seedlings was up to 94% after treated with 500 times dilluted solution of sodium sulfonate.