Study On The Characteristics Of Ornamental Orchid Plants And Their Environmental Adaptation In The Beipanjiang River Basin Of Guizho

Orchidaceae is one of the families with the largest number of species in angiosperms,most of which are of high ornamental value,but few of them are introduced and applied.Guizhou Province has typical karst landform,good hydrothermal condition,highly developed of habitat heterogeneity.As an extremely developed karst landform area in Guizhou,the orchids are rich and special in Beipanjiang River Basin,but the resource background is unclear and the utilization degree is low.Based on this situation,it is urgent to investigate the resources and study on introduction and domestication of Orchids in the Beipan River.In this paper,the wild orchids in Beipanjiang River Basin were taken as the object of study.First of all,carry out field investigation and data collation.Secondly,using analytic hierarchy process(AHP)to establish a reasonable comprehensive evaluation system and screen out the species with high ornamental value.At the same time,for the species that have been screened,studying the correlation between the species and their habitat factors by using clustering analysis and redundancy.Finally,it is expected to provide basic reference for the introduction and domestication of wild orchid resources in Guizhou based on the evaluation of ornamental value.The main results are as follows:(1)There are 249 species(including varieties)of Orchids belonging to 74 genera in Beipanjiang River Basin.Among the 74 genera,includes 7 dominant genera,5 medium genera,27 oligotypic genera and 35 monotypic genera.Among the 249 species,includes 14 species and 4 genera are new recorded in Guizhou.(2)According to ecological adaptation type,249 species can be divided into terrestrial type(143 species),epiphytic type(95 species)and saprophytic type(11species).According to resource richness,they can be divided into widespread species(15 species),local species(94 species),rare species(66 species)and unseen species(74species).(3)There are 2 areas with dense distribution of orchids in the Beipan River Basin,one of them is the junction area of Wangmo and Ziyun withing 107 species,the other is the western area of Panzhou,with a total of 58 species.In the vertical distribution,it presents a "middle expansion type" distribution with the change of altitude,and the mainly distribute range of altitude is 800 ～ 1600 m.Few of them distribute in low altitude area.(4)In the analytic hierarchy process model with 4 layers and 18 indexes,the flower character has the greatest impact on the ornamental value of orchids,the second is the whole character,the third is the leaf character,and the last is the pseudobulb character.Among the 18 indexes,the positive radiation area of single flower can reflect the ornamental value of flower character best,the plant type can reflect the whole character best,and the leaf color can reflect the leaf traits best.(5)According to AHP,the orchids can be divided into three ornamental grades in Beipanjiang River Basin.The first level(51 species)has the highest comprehensive ornamental value,which can be used as bonsai or fresh cut flower with single,or as flower border,flower bed and ground cover with group.The ornamental value of second level(170 species)is ordinary,whose ecological demand is important than the ornamental demand,it can be used as ornamental germplasm resources for proper developmentand.Among the 28 species in the third level,saprophytic orchids accounted for a large proportion,and its ecological value was far significant than ornamental value,it is unnecessary to develop as the ornamental plants.(6)There are 170 groups of similarity coefficients among the seven main environmental factors in the Beipan River Basin,and 104 groups are dissimilarity.It can be seen that the species similarity of orchids under different environmental factors is low,and the distribution of orchids is quite different,which indicates that the difference of habitat heterogeneity in the study area has an important impact on the diversity and distribution of orchids.(7)Combined with the results of hierarchical cluster and redundancy analysis,ornamental orchids in Beipanjiang River Basin can be divided into four functional groups from the perspective of utilization and adaptation to environmental factors: The first is the functional group in low-altitude,Sheltered and non limestone mountain,included Hemipilia flabellate,Dendrolirium tomentosa and Aerides rosea.The second is the functional group of low-altitude,with ample illumina and limestone mountain,included 11 species,such as Cymbidium tracyanum,Cymbidium suavissimum and Cymbidium erythraeum etc.The third is the functional group of medium-altitude,Sheltered and limestone mountain,included 19 species,such as Paphiopedilum malipoense,Paphiopedilum micranthum and Paphiopedilum bellatulum etc.The fourth is the functional group of high-altitude,with ample illumina and non limestone mountain,included Cypripedium lichiangense and Habenaria aitchisonii.The redundancy analysis ordination showed that slope position,vegetation type and altitude were the more important environmental factors affecting the distribution of ornamental orchids,which were generally consistent with the similarity ratio among the environmental factors.Except for individual species with large ecological range and certain dispersion,most of them were clustered in the similar environment,with a high degree of coincidence with the results of systematic clustering.