| There are about 80 species of Orchidaceae Cymbidium plants,mainly distributed in eastern and southeastern Asia to Oceania.In other studies of the genus Cymbidium,the geographical distribution of Cymbidium plants is limited to simple data and statistics,and there is no in-depth analysis and research on the characteristics of its geographical distribution.Define and collect information,establish a geographic information database,quantitatively analyze its geographical distribution characteristics,calculate the inter-species spatial similarity coefficient(K)between various species of orchids,and the shape of each patch of orchids Index(r),maximum patch index(LPI)and various Shannon uniformity index(SHEI),Simpson uniformity index(SIEI).It is expected to provide basic materials and references for the study of the geographical distribution and evolution characteristics of Orchid.The research results are as follows:1.Compilation of C.and collection of species information.Based on literature and specimen information,the catalog of Cymbidium was determined,with a total of 77 species.Establish species information database,including country,city,county,small place name,habitat,altitude and other attributes,a total of 1754 10283 data.Among them,the geographical distribution unit of China is the county,and the distribution unit abroad is the county or its national administrative unit at the provincial level.66 kinds of collected effective information can be used for related quantitative research;61 kinds of collected geographic unit information can be used for spatial distribution pattern research.2.The main distribution units of orchids are in China.The total number of distribution units is 849,and the countries with the highest number of distribution units are 490 in China,78 in Australia,52 in Vietnam,50 in Indonesia,42 in Thailand,31 in Malaysia,29 in Japan,and 19 in India.The single distribution unit has the largest number of species in Napo County,Guangxi,China(14 species).There are only 493 distribution units in one species.3.Geographical characteristics.Among the 66 species,28 species are distributed in the tropics,accounting for 42.42% of the total species,and 17 species are distributed in the temperate zone,accounting for 25.76% of the total species.There are 22 species uniquely distributed in China,accounting for 31.82% of the total species.Most of the endemic species in China are in southwestern China.4.Geographical distribution characteristics.China is the distribution center of the genus,and species richness decreases toward the southeast with China as the center.China(48 species),India(27 species),Vietnam(22 species),Thailand(18 species)Bhutan(18 species),Indonesia(15 species),Malaysia(14 species),Myanmar(14 species)and Nepal(12 species)is a country with a high distribution of orchids.There are 173 species pairs with spatial distribution similarity coefficient greater than 0.1,8 species pairs with greater than 0.5 and less than 1.0,and 3 species pairs with 1.0 equal,ie the distribution areas completely overlap(C.nanulum-C.concinnum,C.recurvatum-C.gaoligongense,C.multiradicatum-C.rhizomatosum).C.are mainly distributed at an altitude of 1000 m-1250 m.5.Spatial distribution pattern.C.canaliculatum is endemic to Australia with the largest patch area;followed by C.ensifolium,C.lancifolium,C.floribludum,and C.goeringii.The largest single plaque area is ranked as C.canaliculatum,C.erythraeum,C.hookerianum,C.iridioides.The smallest plaque area is the C.rectum distributed in Timur,Kalimantan,Indonesia.Chunlan has the largest number of patches(147),and the evenness index is also high.C.rectum has the highest uniformity index,and its Shannon and Simpson uniformity indexes are0.9860 and 0.9800,respectively.The geographical distribution characteristics of orchids indicate that they have obvious distribution centers and unique centers,which are of great significance for further research on orchid evolution and germline differentiation. |
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