Analysis Diversity Of Soil Microorganisms About Different Plant Types From Wanning Coastal Areas

Casuarina equisetifolia is the main tree species of coastal artificial windbreaks in Hainan Island. Compared with coastal natural windbreaks, the natural regeneration capability of Casuarina equisetifolia is difficult, protection periods short, protection effect worse, especially after suffered typhoon attack, operating cost high, therefore, it is urgent for coastal Casuarina equisetifolia windbreak to be regenerated and transformed. Native tree species of Hainan, with high natural regeneration ability, adaptation to the coastal ecological conditions and tolerating poor sandy soil should be selected as alternative tree species of Casuarina equisetifolia windbreak. Based on the analysis to the soil physical and chemical properties of different plant types, the relationships among different plant types, soil microbial and soil were further studied to reveal the effects of different plant types on soil microbial diversity. In addition, obvious effects of different plant types on soil microbial diversity were analyzed. The study will provide new research ideas and methods for the selection of alternative tree species of coastal windbreak.Research method: eight types of plants in three areas of the coastal natural windbreaks in Wanning were selected. There were mainly Scaevola sericea of Maliu corner, Garcinia oblongifolia, Phoenix hanceana and Shrub-meadow, Ficus hispida of Riyue bay and Terminalia catappa, Mallotus paniculatus of Nanyan bay and Vitex tripinnata. Soil sample were collected in October 2013(rainy season) and April 2014(dry season),two layers soil samples of 0~10cm and 10~20 were collected respectively around each types of selected plants within the scope of less than 1m, and 5 point mixed sampling method was used to make a soil sample. Soil physical properties(moisture content), and chemical properties(organic matter, total nitrogen, total phosphorus, total potassium, ammonium nitrogen, nitrate nitrogen, available phosphorus, rapidly available potassium and p H) were determined by common methods. BIOLOG micro plate count method was used to analyze the effects of different plant types on the soil microbial functional diversity. Furthermore, the metagenomics-Miseq sequencing method was applied to make the comprehensive analysis to the soil microbial community diversity. Soil microbial diversity and richness index were analyzed under the levels of phylum and genera. It turned out that the community structure of soil microbial was different over different plant types. Meanwhile, alternative tree species were selected by using comprehensive analysis to the soil micro ecological environment of different plant types.Main results for this study are as follows:1. Different plant types have an influence on the soil physical and chemical characteristics. The highest content of soil organic matter was found in Garcinia oblongifolia; The highest content of total N and total K was found in Vitex tripinnata; The highest content of total P and nitrate-nitrogen was found in Ficus hispida; The highest content of available P, available K and ammonium-nitrogen was found in Mallotus paniculatus, Phoenix hanceana and shrub-meadow. The result showed that different plant types was one of the factors make differ in soil physical and chemical characteristics.2. According to the utilization ability of soil microorganisms to single carbon sources and superior and unique features of its diversity index, the results of soil microbial functional diversity of different plant types with the soil layers of 0~20cm showed that dominant populations of Mallotus paniculatus and Ficus hispida had higher capacity of using the whole carbon sources, Terminalia catappa and shrub-meadow had lower capacity of using whole carbon sources.3. Comprehensive analysis of soil physical and chemical characteristics and the utilization ability of soil microorganisms to single carbon sources indicated that soil nutrients and soil microbial functional diversity in the top soil were higher than that in the subsoil; the influence of soil layers on soil physical and chemical properties was changed with the different plant types; the changes of soil physical and chemical properties over seasons was related to different plant types and soil physical and chemical properties themselves.4. According to the results of high-throughput sequencing Mesiq, 273454 pieces of valid sequence numbers were obtained from seven plant types. The order of sequence number from big to small was Terminalia catappa, Ficus hispida, Phoenix hanceana, Mallotus paniculatus, Garcinia oblongifolia, Vitex tripinnata, Shrub-meadow; 6658 OTUs were obtained in the levels of 0.97 similarity, of which Terminalia catappa was the highest and Mallotus paniculatus was the lowest among them. According to the principal component analysis of OTUs abundances, the diversity of Terminalia catappa, Ficus hispida, Phoenix hanceana was very closed,the diversity of Vitex tripinnata and shrub-meadow was very closed,but the diversity of Mallotus paniculatus,Garcinia oblongifolia was farther away from the other plant types. The study indicated that community diversity was differ in different plant types in the same region. The comprehensive researches of soil microbial diversity and the percentage of soil microorganisms at different taxonomic levels indicated that Terminalia catappa and Ficus hispida had the highest diversity and abundance, therefore Terminalia catappa and Ficus hispida were the species tree with the higher diversity of soil microorganism community, and they contain a large number of unknown sequence, so they can be regarded as the potential trees to improve microorganisms diversity.In general, the changes of soil physical and chemical characteristics, soil microbial functional diversity and community diversity were associated with the different plant types.In the sampled region, Terminalia catappa of RYB, Phoenix hanceana of MLC and Vitex tripinnata of NYB had the highest soil nutrients and community diversity of soil microorganisms. Based on the analysis of different plant types, the order of the diversity of soil microorganism community from high to low was Terminalia catappa, Ficus hispida, Phoenix hanceana, Garcinia oblongifolia, Vitex tripinnata, Mallotus paniculatus.