| Oxystophyllum changjiangense, a rare and endangered epiphytic orchids, is endemic to Hainan Island. Orchidaceae is typical of mycorrhizal plants, there is a complex symbiotic relationship with microorganisms, plant endophytes is able to produce a variety of important bioactive secondary metabolites and great application prospect of a new microbial resources. In order to explore its epiphytic characteristics, the Oxystophyllum changjiangense distributed in Bawangling National Nature Reserve was selected to analyze its preference to epiphytic host, the distribution characteristics on the host, the correlation between population size with DBH and bark properties of host, and so on based on the its resource status, habitat characteristics and diversity of host species. Acquisition the wild living healthy Oxystophyllum changjiangense in different habitats, isolating and identifing the culturable endophytic bacteria and endophytic fungi in its roots. To analys the diversity of culturable endophytic bacteria and endophytic fungi from different habitats,further investigate the relativity between epiphytic characteristics and the diversity of endophytic bacteria and endophytic fungi.This study is conducive to lay the foundation for the protection and utilization of Oxystophyllum changjiangense,for the development of new and useful microbial resources. The main results are as follows :(1) Resources status and habitat characteristics of Oxystophyllum changjiangenseBy referring to the Chinese Academy of Sciences Institute of Botany Herbarium,China Digital Herbarium, South China Botanical Garden herbarium collection records and learned that Oxystophyllum changjiangense had been collected in Wanning City, Sanya City, Ledong City,Changjiang County, Lingshui County, Dingan County,Baoting County,Baisha County, Dongfang County in Hainan.This study finds 34 growth point of wild Oxystophyllum changjiangense,fewer distribution in Hainan Bawangling National Nature Reserve.The Oxystophyllum changjiangense like a place of dark and damp,canopy density is 0.3-0.8. The results showed that the Oxystophyllum changjiangense was growing on the 10-30 m tall arbor nearby the water resources,also growing on the rock wall nearby the water, the humidity is very strict. .As a rare and endangered epiphytic orchids, it is both cluster distribution in horizontal and vertical direction. the 86.6% individuals of Oxystophyllum changjiangense distributed from 800 to 1000m above sea level; The growth forest types of 81% individuals of Oxystophyllum changjiangense is the mountainous rain forest,The soil type where the growth of 81% individuals of Oxystophyllum changjiangense is yellow soil, the growth of the slope is in the range of 10-45°,mostly to the southwest and south slope.Associated orchids are mainly refers to the Dendrobium hainanense, Eria pannea, Eria obvia, Cleisostoma simondii var. Guangdongense and so on,90% of Oxystophyllum changjiangense associated with Dendrobium hainanense.(2) The epiphytic characteristics of Oxystophyllum changjiangenseThis research found 18 host species and most of species belonged to Magnoliaceae,Fagaceae, Anacardiaceae, Anacardiaceae and Sterculiaceae respectively; The epiphytic average advantage of Ficus superba, Canarium album, Castanopsis hystrix, Spondias lakonensis,Bischofia polycarpa is in high degree;the SI of Michelia mediocris ,Reevesia longipetiolata and Castanopsis hystrix is approximately equal to 1; the whole individuals of Oxystophyllum changjiangense were all located on the first branch or second branch of the host, while the difference between on first brand and second branch was not significant;The correlation between individual numbers and host DBH was significantly positive,it has a preference for bark characteristics.The height of epiphytic and host tree had little effect on the number of Oxystophyllum changjiangense, is not obvious.(3 ) The collection of wild Oxystophyllum changjiangense and the separation of culturable endophytic bacteria and fungi in the roots of wild Oxystophyllum changjiangenseTo collected 108 plants of wild Oxystophyllum changjiangense from culturable different habitats and different hosts in Bawangling National Nature Reserve, including from host Canarium album,Cyclobalanopsis myrsinifolia,Bischofia polycarpa,Cyclobalanopsis subhinoides,Ficus altissima,Parakmeria yunnanensis, Elaeocarpus apiculatus Masters, Rhus sylvestris,Cyclobalanopsis patelliformis,Homalium hainanense Gagnep,Spondias lakonensis,Castanopsis hystrix,Ficus superba,Michelia mediocris,and epiphytic on the rocks.498 strains of the endophytic bacteria and 276 strains of the endophytic fungi were isolated in the roots of Oxystophyllum changjiangense from 108 plants of Oxystophyllum changjiangense.(4 ) The identification of culturable endophytic bacteria and fungi isolated from Oxystophyllum changjiangenseAfter morphological and molecular identification analysis, identifing 251 strains of endophytic bacteria and 138 strains of endophytic fungi, a total of 25 endophytic bacterial species, 12 species of Endophytic fungithe.There are at least 10 endophytic bacteria genera,which are Achromobacter, Bacillus, Chryseobacterium, Cronobacter, Enterobacteriaceae,Enterobacter, Escherichia, Pantoea, Pseudoxanthomonas, Providencia,Serratia, Bacillus species are dominant genera. Among those entophytic bacteria strains, Bacillus is dominant genera.There are at least 8 endophytic fungi genera, which are Diplodia, Fusarium,Lasiodiplodia,Neofusicoccum,Pestalotiopsis,Phomopsis,Trichoderma, Xylaria,Among those entophytic fungi strains,Lasiodiplodia is dominant genera. The species and numbers of culturable endophytic bacteria and fungi isolated from the altitude range of 800-1000m were the most abundant, and the relative frequency difference among the other three ranges was the largest.(5)The correlation between epiphytic characteristics and the diversity of culturable endophytic bacteria and fungi in roots of Oxystophylum changjiangenseThis study found that the kinds of culturable endophytic bacteria and fungi of Oxystophyllum changjiangense in Hainan Bawangling National Nature Reserve were highly correlated with the associated orchid species.The DBH of host is closely related to the kinds of of culturable endophytic bacteria and fungi of Oxystophyllum changjiangense. |
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