Diversity Of Slime Molds Under The Canopy Of Major Forest Trees In Nanjing

Myxomycetes are a special group of fungi and protozoa that occur mostly in warm,humid forests.In reproductive stage and the vegetative stage respectively with fungi and protozoa are similar,because of its unique characteristics of life,a reflection is a great group to biodiversity,also because of its unique life history,makes the study of the myxomycetes species diversity for revealing the myxomycetes biodiversity,system evolution,the morphogenesis and differentiation,biological problem has important significance.The investigation and research on the species diversity of myxomycetes in the world are mainly focused on the forest ecosystem,and there are more studies on myxomycetes occurring on the substrate such as fallen wood,rotting wood,litter and standing litter,but there are few studies on the specific substrate under the canopy projected by each tree in the canopy ecosystem.In this study,three areas of Qixia Mountain,Niushou Mountain and Laoshan in Nanjing City,Jiangsu Province,Two subcanopy substrates(including bark 1.5-2 m above the canopy and ground litter in the subcanopy projection area)of eight tree species(Liquidambar formosana,Quercus acutissima,Ligustrum lucidum,Celtis sinensis,Pinus taeda,Cunninghamia lanceolata,Acer palmatum and Pinus massoniana)Species composition and diversity of myxomycetes under canopies were studied by wet chamber culture method.The results show that: A total of 967 myxomycetes were obtained from 2919 wet chamber cultures,belonging to 75 species,18 genera,10 families,6 orders.Two new myxomycete record species in China,Physarum styriacum Gottsb and Lamproderma biasperosporum Kowalski,were discovered,and a list of species of myxomycetes under the canopies in Nanjing was compiled,which can provide an important reference for further research on the species composition of sub-canopy myxomycetes.The species diversity index of Shannon-Wiener was H' = 3.17 ± 1.34,and the evenness index of Pielou was J' = 0.73 ± 0.01.Simpson's dominant concentration index was D'= 0.08 ± 0.01.At the order level,the distribution of myxomycetes was 51.03%,27.57%,9.84%,6.52%,3.32% and 1.72%,respectively.In the relative abundance comparison,the dominant species of subcoronavirus were: Arcyria cinerea(19.54%),Perichaena corticalis(6.23%),Perichaena minor(7.77%),Didymium Squamulosum(7.09%)and Cribraria confusa(5.71%).This study has mastered the species diversity and species composition of myxomycetes under the eight species canopies.The results showed that the species diversity of Acer palmatum was the largest,and that of Pinus massoniana was the smallest.Among the eight species of trees,14 types of myxomycetes occurred on the bark substrate under the canopies of Acer palmatum,and 17 types of myxomycetes occurred on the litter substrate,but the similarity of the species composition of the myxomycetes on the two substrates was only 25.81%.This indicates that the bark substrate and litter substrate under the canopy of Acer palmatum are more suitable for the occurrence of myxomycetes under the canopy.Among the 75 kinds of myxomycetes obtained in this study,26 kinds of myxomycetes showed preference for specific tree species.The analysis of species diversity of myxomycetes under the canopy showed that:in terms of the relative abundance of species,the order of the three regions was Qixia Mountain > Niushou Mountain > Lao Mountain,and the order of the eight species was Liquidambar formosana > Celtis sinensis > Quercus acutissima > Ligustrum lucidum >Acer palmatum > Cunninghamia lanceolata > Pinus taeda > Pinus massonian.The litter substrate was better than the bark substrate.In terms of the species diversity results of myxmolds under the canopy,the three regions were ranked as Niushou Mountain >Qixia Mountain > Lao Mountain,and the eight species were ranked as Acer palmatum >Celtis sinensis > Liquidambar formosana > Quercus acutissima > Cunninghamia lanceolata > Ligustrum lucidum > Pinus taeda > Pinus massoniana.The litter substrate was better than the bark substrate.The canonical correspondence analusis(CCA)analysis revealed that trees and sampling sites had significant effects on the species diversity of myxomycetes under canopy,but the seasonal effects were not significant.The results of this study can reveal the species diversity and species composition of eight species under the canopy of trees,and evaluate the best season for the occurrence of species diversity under the canopy of myxomycetes,as well as the most suitable sites for the occurrence of myxomycetes under the canopy.