Diversity Of Slime Molds In Baotianman National Nature Reserve

Myxomycetes are unique for their multinucleate plasmodia and dispersing by spores.Their occurrence is influenced by geographical and climatic factors,showing recognizable distribution patterns.Studies on diversity of myxomycetes have always been carried out in European and American areas.The central China is a region with extremely high richness and specificity of plant species,but the myxomycetes in this area remain to be covered.To enrich the species diversity information of myxomycetes in central China.We chose the Baotianman National Nature Reserve as a sampling ground.Systematic surveys were carried out based on occurrence of fruiting bodies and environmental sequencing.The main research contents and results are as follows:Field collections combined with moist chamber cultures yielded 1046 specimens.A total of 96 species belonging to 31 genera were identified.Three new recorded species for China were reported,including Licea castanea G.Lister,Fuligo luteonitens L.G.Krieglst.& Nowotny and Didymium saturnus H.W.Keller.A checklist,listed all known species,was constructed based on taxonomic results.The myxomycetes in Baotianman could be classified into the following distribution types: cosmopolitan(30.21%),East Asian-European-North American(25.00%),temperate(41.67%)and tropical(3.12%).It is clear that the myxomycete flora of Baotianman is dominant by temperate element,and have closer kinship to those in Europe and North America.Five study sites were established in Baotianman reserve.Myxomycete specimens and substrates for moist chamber culture were collected at monthly interval from April to October in 2016.A total of 688 myxomycete specimens were obtained and 71 species were identified,with Arcryia cinerea,Hemitrichia minor,Perichaena depressa,Diderma effusum and Perichaena corticalis recorded as abundant.Among the two types of substrates investigated,the litter is inhabited by more species(55)than bark(35).The ?-diversity of myxomycetes were mainly influenced by forest type and sampling month rather than elevation.The highest overall ?-diversity were observed in mixed broadleaf-conifer forest(S = 16.00 ± 2.55,H' = 2.48 ± 0.13),with the ?-diversity of litter-inhabiting myxomycetes followed the similar patterns;While the bark-inhabiting myxomycetes tended to reach highest ?-diversity in deciduous broadleaf forest(S = 6.00 ± 1.11,H' = 1.66 ± 0.19).Significant differences in ?-diversity were observed between the 7 sampling months.According to moist chamber culture,the highest values were recorded from substrates sampled in April,whereas the lowest values were recorded in September.For the field collections,specimens were mainly collected during June to October,with the ?-diversity recorded as highest in July(S = 9.00 ± 2.67,H' = 1.82 ± 0.25).Different ecological patterns were observed for the bark and litter inhabiting communities.The former was closely linked with forest type and further drived by tree species,elevation and bark features.The latter changed in seasonal patterns and were mainly determined by substrate type and climate factors.Seventy-five soil samples were collected representing 6 forest types and 3 seasons.The dark-spored myxomycete sequences were generated using Illumina sequencing method.A total of 195 OTUs were identified,in which 105 OTUs could be assigned to order Physarales and the remaining 90 OTUs to order Stemonitidales.The similaritybased assignments showed that 47 OTUs could be taxonomically annotated to genus level,representing 11 genera.Stemonitis is the most dominant which account for ca.10% of the total sequences,followed by Diderma(7.53%).In addition,8 species were identified,including 3 nivicolous species recorded from subtropic of China for the first time.The ?-diversity and community structure differed significantly among the forest types,with the highest ?-diversity observed in Pinus armandii forests(OTU richness = 37.88 ± 8.40,H' =2.29 ± 0.30)and lowest in Quercus serrata forests(OTU richness = 20.00 ± 6.40,H' = 1.64 ± 0.41).However,no seasonality was observed for the myxomycete community in our data.The OLS Multiple regression analysis indicated that the ?-diversity responded significantly to forest type,C:N and K.According to the multivariate analyses,forest type was the strongest predictor of the myxomycete community structure,but soil pH,C:N and other spatial factors also showed significantly correlations.Investigations on myxomycete were also carried out in other representative mountain forest in central China.Two new species,Arcyria aeruginosa and Diderma subochraceum were reported.A.aeruginosa is collected from Shunhuangshan forest park in Hunan province,and differs from all known species of the genus in having dense spines on inner surface of cups.D.subochraceum is reported from Simianshan forest park.Its diagnostic feature is single-layered peridium which dehisces by longitudinal or stellate slit.