热激处理对白桦幼苗温度适应的影响

以白桦为研究对象 ,人为模拟高温 ,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对 1年生白桦幼苗的伤害程度以及高温预处理对白桦幼苗温度适应的影响 .结果表明 ,膜相对透性及丙二醛含量在 37℃和 4 2℃热激处理的 2 4h期间出现升、降、升的变化趋势 ,但 37℃ 2～ 4h处理为白桦热激反应的理想条件 .37℃ 4h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

Effects of heat shock on subsequent chilling sensitivity and thermotolerance of birch saplings

One year old Betula platyphylla saplings were exposed to different high temperatures, and the interaction between high temperature and exposure time was studied in the laboratory. The results indicate that the electrolyte leakage and MDA content increase first, then decrease and increase again during the 24 h when holding birch saplings at 37 ℃ and 42 ℃. However, the heat injury to birch at 37℃ seems gentler than that at 42℃. In addition, exposure for 4 h at 37 ℃ can both increase subsequent chilling sensitivity of birch saplings and improve their high temperature tolerance.