【作者】 曲桂芹；

【导师】 聂绍荃； 祖元刚；

【作者基本信息】 东北林业大学 ， 植物学， 2001， 博士

【摘要】 热激反应是生物体对高温胁迫的一种应激反应，由于其具有反应快速、直接的特点，逐渐成为研究生物体与环境间相互作用的模式系统。近来，热激反应与多种环境胁迫之间的联系，使人们愈加重视它在植物生理、生态及生物进化中的作用，并成为多个领域研究热点。 1、本文以东北地区分布范围广、适应性强的白桦为研究对象，人为模拟高温条件，对一年生白桦幼苗进行不同温度、不同时间的热激处理，以质膜相对透性和丙二醛含量为主要测定指标，比较了不同高温和不同处理时间相互作用对白桦幼苗的伤害程度。在37℃和42℃热激处理的24小时期间，白桦幼苗叶片的质膜相对透性和丙二醛的含量均有明显变化，变化趋势基本一致，但变化幅度37℃小于42℃。热激初期（4h之内）两项指标均呈现上升趋势，4h后则逐渐下降，但热激时间超过12h，质膜相对透性和丙二醛含量急剧上升。整个热激处理期间，37℃下的幼苗外在的生长势良好，而42℃下的幼苗当胁迫超过8h即显现热害症状。因此，白桦的最佳热激反应温度确定为37℃。 2、不同热激预处理既可提高白桦幼苗的耐冷性又可提高白桦幼苗的耐热性。37℃高温处理4h的白桦幼苗转置2℃ 24h，其质膜相对透性和丙二醛含量明显低于未经高温预处理的和42℃热激处理4h的幼苗；37℃热激胁迫4h的幼苗放入45℃2h，受伤害的程度明显低于直接放入45℃ 2h的幼苗。热激胁迫对白桦幼苗耐冷性和耐热性的提高，填补了树木热激反应在其温度适应研究领域的空白，说明热激反应是研究树木温度适应的一种很好模式系统。 3、比较了三种树木RNA的提取方法，确定改良的CTAB法为白桦组织RNA的最优的提取方案。其为一种快速、可靠的树木RNA提取方法。 4、建立了适应白桦的mRNA差异显示分析体系，优化了反应条件和反应程序。利用三种锚定引物和24种10碱基随机引物组合，展示了东北白桦正常条件下和热激条件下基因表达的差异图谱。为在RNA水平研究白桦个体/群体与环境之间温度适应机制提供了相应的理论和方法学基础。对热激条件下白桦叶片组织高表达的4个差异片段进行了回收、克隆和测序分析。更多还原

【Abstract】 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.更多还原