Soil Dematiaceous Hyphomycetes From The Arid-semiarid Zones Of Northwest China

This study is a part of the project on fungal diversity of dematiaceousHyphomycetes from soil in China. It was aimed at clarifying the diversity atgenus and species level, the survival and distribution status and the ecologicalsignificance of the soil dematiaceous Hyphomycetes in the arid-semiarid zonesof northwest China as the basis for further studies and utilizations.The 150 soil samples were collected from representative sites selected inGansu, Shaanxi Provinces, and the Xinjiang Uygur Autonomous Region andthe Ningxia Hui Autonomous Region. the 500 fungal isolates were got fromthose soil samples using soil plate methods and dilution plate methods.Determination of the isolates yielded 82 species in 35 genera.Among them 15 taxa are new species.They are EmbelIisia microspora.Fusariella verrucosa. Graphium wuweiensis. Monodictys alternariae.Papulaspora deserticola. Phialophora pseudoobovata. Pyricularia kuerleensis.Scolecobasidium ellipsoideum. Stachybotrys akesuensis. Stachybotrysterrestris. Stachybotrys pseudocylindrospora. Stachybotrys tshawytscha.Ulocladiurn dunhuangensis. Veronaea cylindrospora and Veronaea akesuensis.Eight species are new for China: Acremoniella atra (Corda) Sacc.,Acremoniella verrucosa Tognini, Alternaria chlamydospora Mouchacca,Phialophora cinerescens (Wollenw.) Beyma, Stachybotrys albipes (Berk. &Broome) S. C, Jong & Davis, Stachybotrys dichroa Grove, Ulocladiummicrosporum A. H. Moubasher & S. L. Aedel-Hafez and Veronaeaoblongispora G. Morgan-Jones.A new variety is Stachybotrys cylindrospora C. N. Jensen var. terrum.Three species undeterminated are Arthrinium sp., Leptographium sp. andScolecobasidiurn sp..All specimens (dried cultures) and living cultures studid have been deposited in the Herbarium of Shandong Agricultural University: PlantPathology (HSAUP).Based on experiences of the author, colleaques and previous reseachers inthe laboratory, a series of experimental methodswhich include isolation,cultural methods, germination test and sporulation stimulating measures etc.on soil dematiaceous Hyphomycetes were improved. Some of taxonomicveiwpoints on some genera and species of interesting soil fungi were discussed.1. The nature condition of northwest China was simulated during isolation andculturing, for example: utilizing lixivium of soil medium, drying in short timeand changing pH, and so on. These methods are very helpful for getting morefungal isolates from soil and stimulating sporulation of some fungi.2. Characters of conidiophores, types of conidiogenesis, the stretchingpatterns of conidiogenous cells, conidium shape and septation were the maincriteria used to classify the fungi at genus level, while the morphology ofconidia and conidiophores were the main characters in differentiating fungalspecies. The color of colonies could not be applied as taxonomic criteriagenerally. Otherwise, depending on characters of condia could not differentiateStachybotrys and Memnoniella.3. Fungal distribution in the soil is various, The distributions of the fungi inHyphomycetales is more widely than that in Stilbellales and Tuberculariales insoil. The distribution status of fungi might be different in different locationsand the types of soil.