齿瓣石斛病原链格孢菌生物学特性研究

对齿瓣石斛(Dendrobium devonianum Paxt.)黑斑病病原物链格孢菌(Alternaria tenuis Nees)进行分离并对其生物学特性进行研究.用常规组织分离法从齿瓣石斛叶片中分离黑斑病病原物链格孢菌,以PSA为基本培养基,研究培养基pH值、附加不同碳源和氮源、温度、光照等培养条件对链格孢菌菌丝生长及产孢的影响.齿瓣石斛链格孢菌菌丝最适宜生长的温度25℃,20℃最宜产孢;最适宜的pH值为5～6;光照对菌丝生长影响不显著,产孢量以光暗交替下培养最多;在PSA培养基上加入淀粉或硝酸铵对菌丝生长最好,产孢则以葡萄糖较好,在其他碳源或氮源的培养基上极少产孢.齿瓣石斛链格孢菌适宜在PSA培养基pH值为5～6,附加一定葡萄糖和硝酸铵,25℃和光暗交替下生长.

Biological Characteristics of Dendrobium devonianum Pathogen Alternaria tenuis Nees

To isolate the Alternaria tenuis Nees from infected leaves of Dendrobium devonianum Paxt. and study the biological characteristics of this pathogenic fungus. Isolated the A. tenuis Nees from infected leaves of D. devonianum Paxt. according to the method of Fang ZD first and then used PSA as basic media to study the effects of pH value, different carbon and nitrogen sources ,temperature and illumination on mycelial growth and sporulation of A. tenuis Nees. Results :The optimal temperatures for mycelial growth and sporulation of A. tenuis Nees isolated from D. devonianum Paxt. were 25℃ and 20℃ respectively. Media with pH values between 5.0 and 6.0 were beneficial for mycelial growth and sporulation of A. tenuis Nees. Illumination did not have significant effect on its mycelial growth while daily alternation of 12 hour's lighting and 12 hour's dark at 25℃ gave the highest spore yield. PSA media supplemented with starch or ammonium nitrate provided best results for mycelial growth. PSA medium with glucose was suitable for sporulation of this fungus. The fungus inoculated on PSA media with other carbon and nitrogen sources produced very few spores. A. tenuis Nees isolated from D. devonianum Paxt. could be cultured on PSA media with pH values between 5.0 and 6.0, glucose and ammonium nitrate at 25℃ and under the daily alteration of half lighting and half dark.