|其他摘要||Psammosilene tunicoides W.C.Wu et C.Y.Wu is a monospecifc plant of the genera which mainly distributes in the northwest, middle, northeast Yunnan and also Sichuan, Guizhou, Tibet. It is now embodied in Red Book of Chinese Plant, and classified as second degree national priority protection plant. As a major component of ‘Yunnan Baiyao’, we must study on its germplasm resources for guaranteeing the high, stable quality of the medicinal plant and establishing the descriptors and data standard of its resources.
Pasammosilene tunicoides W.C.Wu et C.Y.Wu is a endangered medicinal plant with distribute only in southwest China. Studies of morphology, cytogenetics, sequencing of AFLP, phytochemistry, biogeography, favorable eare, breeding, pollination were performed on the species, trying to reveal the divergence pattern and relationship among different geographical populations within the species and analyze its endangered reasons, more important to use isolating and analytic method researching the effective compounds and its standard extract. We have taken further steps to cloning the cDNA of a key gene relation to effective compounds----squalene synthase.
There are discrepancy of the form of bractlet, petals etc. between individuals among population, but the shape of the leave is relatively stable by observing morphological characters. Psammosilene tunicoides has widely adaptation to moisture and nutrition. We have used CLIMEX 1.1 in first on the nation's 222 points of climatic and geographical factors of analysis, Tibet, Sichuan, Yunnan and Guizhou is favorable eare for it.
Psammosilene tunicoides has a hybrid mating system. It is an allogamous, entomoplily and inbred reproduction plant, and can be self-pollination. The insect of pollination is Apis cerana, Eristalis tenax etc. According to the study on the plant of 6 populations, it has 24 stripes of chromosome, 2n=24, x=12, a quantitative difference from others` 2n=28. The plant can be propagated rapidly by tissue culture.
Using the method of Amplified fragment length polymorphisms (AFLP) to investigate the genetic diversity of 9 populations of Psammosilene tunicoides, the result is that: genetic diversity of it is relatively high at the species level(PPB＝86.00%，He＝0.2831), but is lower within populations (PPB＝32.5%，He＝0.0858); There are extremely high levels of population genetic differentiation among populations: The genetic differentiation (Gst) is 0.6977 and genetic differentiation by Shannon’s diversity (Ist) is 0.6975. The distance among these geographical populations is not consequent on its genetic distance. We have found the 9 characteristic fingerprints that can be used to identify the geographical populations and supplied a deficiency of the research of its diversity and characteristic fingerprint.
In order to establish the method for the quality control of the medicinal plant, the standard extract was prepared which set up with the experiment of multi-factors by HPLC technique. A primary phytochemical investigation led us in the first place isolate the gypsogenin 3-O-(6’-O-Methyl)-β-D-glucuronopyranoside, and choose it as characteristic constituent, prepare the standard compound, establish the method of determining effective content. We have gotten the result that there are difference of effective contents among the populations by the method of HPLC.
For the first time a full-length cDNA fragment of Squalene synthase of Psammosilene tunicoides was isolated by the method of RT-PCR and RACE. Squalene synthase that can catalyzes the first enzymatic step in sterol and triterpenoid is a key regulatory point modifying the total triterpene saponins biosynthesis. This work provided an basis for the study on Psammosilene tunicoides Secondary Metabolism, and replenished the knowledge of the genes. Comparing the order of amino acid of Psammosilene tunicoides squalene synthase with the others`, we have gotten the result that Psammosilene tunicoides of Caryophyllaceae is close to monocots, and is a distant relative of eudicots, it may be occurred formerly as a distinct branch than eudicots.|