Study On Cytology And The Relationship In Plants Of Paphiopedilum (Cypripedioideae: Orchidaceae)

Paphiopedilum Pfitzer is more primitive genus in the Orchideceae. Duing to long florescence and kinds of colors, it is the most favorite ornamental orchids from which more than 10000 of artificial hybrids have been bred since 1850s. Our country has more about 18 species of Paphiopedilum. South and southwest China is one of the distribution centers of this genus, where these species of Paphiopedilum are still facing continuous original environment destruction and demand for wild plants though they have become rather rare today. Now, Paphiopedilum has already listed in AppendixⅠin order to control imports and exports strictly.At present, the research about Paphiopedilum is still comparatively backward in our country. Taking these morphological characteristics still is the core in taxonomy-based classification. As an important area of classification research, cytology has not been involved in the country. 21 kinds of cultivated Paphiopedilum plants were used in this study. The chromosome number,the karyotype formulae, the karyotype, arm ratio, relatived length, index and karyotypic asymmetry etc were studied and analyzed by root tips squash method. The origin, systemic evolution, taxonmy and crossbreeding of twenty-one species including P.malipoense, P.concolor etc of Paphiopedilum have been analyzed. Image analyses were performed with Image Motic Images Advanced 3.0 and Photoshop7.0 software. Combined with morphology and geography of Paphiopedilum, a detailed analysis and speculation on the relationship of taxa concerned was conducted and deduced. The aim of this study accumulated the essential cytology information on classification, which can afford some proof for evolutionary trends, protection and crossbreeding for Paphiopedilum Pfitzer. All the results were as follows:1. Actively growing root tips pretreated with 1-Bromonaphthalene for 20-24h at 4℃and hydrolyzed in 1mol/L HCl at 60℃for 3min were better than other methods during making slices of Paphiopedilum chromosome.2. These 21 kinds species studied were different in the chromosome number. The most...