Classification Of Microascales And Ophiostomatales In China

The order Microascales was reported as a saprophyte and parasite. It is host including plant and animal, even human. The classification always changes since the order erected. In this thesis, the author discussed the range of the order and the present situation on the taxonomy of the genera relied on practical work. Morphology of ascomata, ascospore, and presence of ascomatal hairs and character of anamorph was used to delimite the genera. The characteristics of ascospore, such as size, shape, symmetry, structure, pigmentation, presence, position and number of germ pores are the most important classified criteria of species. The size, shape of ascomata and ascus are useful to identify species. The ascomatal hairs have been seen important taxonomic standards; however, they usually neglected because they varied as time and the environmental change. Although a few species produce anamorph, the structures of anamorph were notably differential among them, the morphology of anamorph should consider as one of the criteria. Growth rate, pigmentation and exudates of colonies are with some extend value for delimitation species.The most species of the order Ophiostomatales was founded on forest wood. Many species are economic importance because they cause blue-stain in lumber and forest product. This group of organisms having complex relationships with insect vectors. Most species produce at least two spore types and use these to accomplish fertilization and dispersal. The fungus produce a great variety of anamorphs, often even within one species. Biological characteristics of Ophiostomatales were valuable to identify genera and species.The species of Ophiostomatales and Microascales which were difficult to be identified through morphological were analyzed by the internal transcriber spacer (ITS) of ribosomal. The analysis of ITS indicated the sequences have difference in different genus and have difference among species in the same genus. Phylogenetic analysis of nucleotide sequences conducted was using maximum parsimony methods.On the basis of morphological characters, more then 500 specimen from Shaanxi Province and Gansu Province were isolated and identified, including plant debris or wood 412, soil and dung 103. 7 genera and 15 species described, including 2 new record genus: Petriella and Pseudallescheria, 8 new records species: Petriella guttulata,Petriella sordida, Pseudallescheria ellipsoidea, Pseudallescheria boydii, Lophotrichus plumbescens, Ophiostoma querci, Ophiostoma canum, Ceratocystis allantospora.