| As a national rare and endangered species– Rh.Chrysanthum, has become the dominant species in Changbai Mountain. Rh.chrysanthum. at alpine tundra zone(2614m)showing a patchy distribution; a large distribution of Rh.chrysanthum from alpine tundra to birch belt and the main distribution area, hill and dale, grew well, developed root system, dense foliage. Research on population distribution and adaptation mechanism of plant has been an important issue in the plant protection field. Adaptation mechanism of plant is extremely complex process in which different plants to adapt to the environment, and gradually formed its own unique adaptations. Based on previous studies on the genetic structure of Rh.Chrysanthum, In this experiment, additional studies on genetic diversity and population structure of Rh.chrysanthum.in the small differences elevation, and then analyzed the interaction between the expand distribution and its population adaptability. The same time, we observed the cell anatomic structure of leaf and analyzed the relationship between internal structure and environment change and then the adaptive mechanism of plants. In addition, we chosed the mRNA differential display to clear the differences of resistance which show up when plants were facing the environment change, aim at reveal the molecular mechanism of Rh.Chrysanthum adapting to complex environment.The final results show that:1 Using randomly amplified polymorphic DNA (RAPD) marker, we investigated the genetic diversity and population structure between two Rh.chrysanthum populations of different elevation. First fourteen RAPD primers produced a total of 139 bands, of which 98 (70.5%) were polymorphic and produced on an average of 7 polymorphic bands per primer. The results show that high level of genetic diversity of Rh.chrysanthum populations; Total genetic variation Ht was 0.2400, and the genetic variation within populations Hs was 0.2256, genetic variation existed mainly within populations rather than between populations. The genetic differentiation coefficient Gst which was analyzed based on Nei's genetic diversity among populations was 0.0597, indicated the genetic variation between different populations accounted for 5.97 % of the total,the gene flow between populations was 7.8788, Analysis of molecular variance(AMOVA) showed that about 88.59%of the genetic variation was attributed within populations, while the remaining 11.41%among populations,the results consistent with the analysis of PopGen32 software. Genetic diversity is the basis of all biodiversity and is widely recognized as a key requirement for the long-term survival of species on an evolutionary time-scale. The environmental which is stressing survive of plants will enrich genetic diversity of species and this genetic diversity return to contribution in their faster and better adaptability to the changed environment, or more extreme and harsh environments.That is the strategies to response to the significant heterogeneity environment. The expansive distribution of Rh.Chrysanthum populations developed in this interaction with the environment and has become the main advantages species of tundra ecosystems in Changbai Mountain.2 Four groups materials are the fresh leaves of Rh.chrysanthum in four different elevation, observation on anatomical structure of leaves have shown: bifacial leaf that leaf surface were different from the other side; composed of epidermis, mesophyll and vein; mesophyll tissue significantly differentiation; palisade tissue cells tightly packed; spongy tissue loose. Gradually increased with altitude, the stratum corneum of covering leaf epidermal cells gradually thickened, the average thickness of paisade tissue and leaf increased, analysis shows that these structural changes are adaptation of plants facing the strong radiation, drought and other complex environment in high altitude.3 In the mRNA differential display (DDRT-PCR) experiments, first using a modified CTAB method, the total RNA were extracted from Rh. chrysanthum leaves in four different altitudes, and then reverse transcribed to be cDNA use the anchor primer. 24 combinations were random composed of designed 3 anchored primers and eight random primers, finally 24 PCR amplification products generated, and then differential display on the 6% polyacrylamide gel. 13 different fragments were extraction, then purified, cloned and sequenced, using the BLAST tool compared sequencing results with the GenBank sequence database which have been entered, four different sequences, the lengths of 323bp (2#), 171bp (4#), 226bp (8#), and 334bp (10#). 4# fragment is 94% homology with fatty acidα-hydroxylase 1 (FAH1),96% homology with the fatty acidα-hydroxylase 2 (FAH2) in Arabidopsis thaliana. Analysis shows that responses of Rh.chrysanthum to environmental stress were immediately start the protection mode: abundantly expressed FAH, changes the cell permeability, supression of cell death. Low homology between the other segments and sequence in GenBank: 2# fragment is 64% homology with mRNA sequence of sunflower under drought conditions; 10# fragment is 53% homology cDNA sequence of Vaccinium corymbosum, and 49% homology with response protein sequence when Arabidopsis thaliana or Barley was in stress. 8# fragment is 51% homology with Se-responsive genes in a selenium-hyperaccumulator Astragalus racemosus or mRNA sequences in pre-flowering to post-flowering stages of Diospyros kaki.
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