Study On Molecular Ecology Of Heat Shock Response In Betula Platyphylla

Heat shock response is a conserved reaction of organisms to elevated temperature, and it is becoming a model system of a genotype-environment interaction for its characteristic of transient and direct. I One year old Birch saplings were exposed to different high temperature, and the interaction between high temperature and expose time was studies in the laboratory. Holding Birch saplings at 370C or 420C for 24 hours, the electrolyte leakage and Ml)A content were increased within first 4 hours, then they decreased between 4 hours to 12 hours. After 12 hours, the rate of electrolyte leakage and MDA content increased rapidly. But the heat injury to Birch at 370C were gentle than the injury at 42aC. 2 ~ Prior high temperature exposure affected Birch subsequent chilling sensitivity and improved their higher temperature tolerance . One year old Birch saplings were exposed to 370C 4 hours and then immediately held at 20C 24 hours, the electrolyte leakage and MDA content were lower than the trees directly held at 20C 24 hours. When saplings were pre-incubated at 370C 4 hours following be kept at 450C for 2b, which can be protect against heat injury. While unheated sapling directly placed at 450C 2h, the rate of electrolyte leakage and MDA content increased rapidly. Therefore, the temperature adaptive mechanisms caused by heat shock may be an ideal model system on studying the interaction between Birch and environment. 3 ~ Three methods were compared in the extraction of total RNA from Birch leaves. CTAB methods were the ideal for the trees?total RNA extraction, and it was also a quick and effective method for other trees. 4 mRNA differential display system of Birch was established. Content of Mg2~, dNTP, cDNA templates concentration were tested and the optimal reaction system of DD-RT PCR for Birch was determined. Combined 3 anchored primer and 24 arbitrary decainer, differential display pattern of the total RNA from control and heat shock Birch leaves were established. Four fI-agrnents which were differentially expressed in heat shock Birch leaves were isolated, cloned and sequenced.