Study On Species And Ecological Distribution Of Soil-Inhabited Pythium In Southern Guangxi

Pythium is a genus of oomycetes. For their ecological diversity and physiological uniqueness, it is of great significance in theory and practice to study them. During 2002-2003, 142 specimens has been collected ,which come from 15 areas. Mainly based on morphological characters ,150 strains were identified as 29 species,besides 6 strains as 2 unknown species which couldn't be indentified according to current reference datum. Among them 20 species were new records in Guangxi, as followed, Pythium acanthicum Drechsler , Pythium afertile Kanouse & Humphrey, Pythium amasculinum Yu, Pythium aquatile H hnk, Pythium carolinicmum Matthews , Pythium catenulatum Matthews , Pythium dissottcum Drechler, Pythium elongatum Matthews , Pythium helicoids Drechsler , Pythium hemmianum Takahashi, Pythium intermedium de Bary , Pythium mamillatum Meurs , Pythium myriotylum Drechsler , Pythium oligandrum Drechsler , Pythium paroecandrum Drechsler , Pythium periplocum Drechsler , Pythium perplexum Kouyeas&Theohari, Pythium pulchrum Minden, Pythium sinense Yu, Pythium torulosum Coker&Patterson. Research showed that Pythium spinosum Sawada, Pythium deliense Meurs and Pythium acanthophoron Sideris were dominant species of Pythium community in this region, Pythium spinosum Sawada was the most wide-ranging species for its powerful adaptability. Among 15 areas, Manning had the largest Pythium community.On the aspect of relationship between soil factor and Pythium community distribution, research indicated Pythium prefer heavy-textured loamy soil which should be abundant humus and slight acidity.