植物对热刺激的反应

RESPONSE OF HIGHER PLANTS TO HEAT SHOCK

本文以高粱(Sorghum bicolor)幼苗为材料,研究了植物对热刺激的反应。将幼苗从30℃的培养温度迅速地移至一个较高而非致死的温度范围内时,发现其组织细胞内合成一些异常的蛋白质,通常称为热应激蛋白。他们是一组 66—117 kD的高分子量蛋白和一个18kD的低分子量蛋白以及几个介于二者之间其分子量33—66kD的蛋白。幼苗根组织细胞和地上部组织细胞对热刺激显示出类似反应,但也存在一些细微上的差异。此外,还观测到这些热应激蛋白的诱导速率是非常迅速的。将幼苗从30℃移至45℃时,仅一个小时的热刺激就明显地检测到它们的合成,但最大的诱导和合成累积则是发生在热刺激的第二个小时,随即合成速率迅速下降。

When sorghum seedlings were rapidly shifted from the cultural temperature of 30℃ to 40℃ and 45℃, a set of abnormal proteins, generally referred to as heat shock proteins were induced. They are a group of high molecular weight proteins (about 66--117 kD), a few intermediate molecular weight proteins (33--66 kD) and a low molecular weight protein of 18 kD. At the same time, the synthesis of normal proteins was relatively depressed. The res- ponse of the shoot tissues of sorghum seedings to heat shock is similar to that Of the root tissues, but there are some differences in more detail between the two tissues. The synthesis of heat shock proteins in sorghum seedlings was rapid. After one-hour exposure at 45℃ their synthesis in the roots was detectable. Maximum induction took place in the second hour of exposure, thereafter their synthesis began to decline markedly. Finally, there appear to be some proteins whose synthesis was not supressed during heat shock. It is not yet known why the synthesis of these proteins is so stable.