| Rhododendron chrysanthum Pall long-term growth in changbai mountain of 1689 ~ 2401 meters above sea level Erman’s Birch forest zone to the alpine tundra, annual average temperature between-7 ℃ and 3 ℃, in the extreme environment conditions, the morphological structure of gradually formed can resist the adversity stress and genetic physiological and biochemical mechanisms. This study of changbai mountain rhododendron chrysanthum pall(hereinafter referred to as rhododendron) leather anatomical structure and the principle and biochemical indexes, and cold-resistant micro RNA393 expression, which provides the theoretical foundation for the study of stress resistance mechanism in rhododendron.1. Research on anatomy in Rhododendron: rhododendron leaves and stems of crosscutting, carries on the comparison to its anatomical structure, results show that the leather rhododendron seedling leaf is the main vein vascular bundle developed than tissue cultured seedling, bear ability. Rhododendron many layers of palisade tissue, spongy tissue and the intercellular space is not developed. Somaclone loosely arranged epidermis cells, cells is bigger. Pith ray in the vascular cylinder in Rhododendron developed than tissue cultured seedling, and closely packed.2. Research on physiological and biochemical index determination in Rhododendron: the rhododendron leaf chlorophyll content and chlorophyll relative content(SPAD value) were determined, the results show that the leather chlorophyll content and SPAD values are higher than tissue cultured seedling, the long high light with rhododendron, photosynthetic rate are related. Results of determination of protein content show that the leather rhododendron protein content is higher than the tissue cultured seedling, its growth conditions, in order to withstand adversity will accumulate a lot of protein. superoxide dismutase(SOD), malondialdehyde(MDA) and peroxidase(POD) and catalase(CAT) activity in rhododendron leaf was determined, the results showed that the vigor of SOD, POD and CAT of rhododendron is higher than the tissue cultured seedling, except MDA. Dynamic response ability of membrane lipid peroxidation, MDA and SOD reaction plant the ability of scavenging free radicals, POD, CAT and SOD have synergy, removal of reactive oxygen species in the system, the resulting rhododendron resistance stronger. Results of sugar content show that the leather rhododendron ’s percentage is higher than the tissue cultured seedling, significant differences between them.3. Optimization study on RNA extraction method of Rhododendron: because of rhododendron special growth environment, the secondary metabolites in the body also far higher than that of other species, species and content of polysaccharide polyphenols a large number of accumulation, using the method of CTAB and Trizol + CTAB method can extract to the high quality RNA. Finally RNAiso + CTAB method is used to extract rhododendron RNA, the polysaccharide to minimize the effect of polyphenols on the experiment, easy operation and quick, full of RNA, DNA pollution, can satisfy the follow-up study of the molecular level.4. Expression analysis of cold-tolerance mi R393 genes in Rhododendron: hardy mi R393 only 21 nt, ordinary primers cannot reverse transcription, design specific primers, stem-loop primer on the reverse transcription, again by semi-quantitative RT-PCR for rhododendron mi R393 gene expression analysis, structure shows mi R393 gene expression after exposure to the cold stress increases, the preliminary evidence that mi R393 genes associated with rhododendron cold stress response... |
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