【摘要】 本实验用蔗糖密度梯度离心分离小麦叶片的核糖体,用 SDS-聚丙烯酰胺凝胶电泳分离叶绿体蛋白质。对在高温和常温条件下生长的小麦分析比较表明:在34℃高温下,小麦叶片能正常地形成细胞质的80S 核糖体,而影响了叶绿体的70S 核糖体的形成,从而使由叶绿体基因组控制的蛋白质的生物合成受阻。由 SDS-凝胶电泳分析表明:高温处理的小麦,其叶绿体蛋白质的电泳条带少于常温下生长的小麦。在这些消失的多肽中,主要是叶绿体基因组的翻译产物,如二磷酸核酮糖羧化酶大亚基。由于叶绿体内这些具有光合生理功能的蛋白质的合成受阻,从而导致小麦叶片光合强度的降低。更多还原

【Abstract】 The chloroplasts of wheat have chanced greatly at high temperature con- dition(34℃).When wheat grown at 34℃ for 10 days,its chlorophyll content was 6 times less than that under the normal condition(22℃).The ribosomes were isolated from the leaves by sucrose density gradient centrifugation.It is found that only 80 S ribosomes existed in wheat leaves grown at the high temperature and the formation of 70 S ribosomes is specifically prevented.Since the absence of 70 S ribosomes in chlo- roplast,proteins synthesis can no longer proceed.Analysis of SDS-polyacrylamide gel electrophoresis indicates that the bands of chloroplast proteins from the leaves of wheat at the high temperature are less than those under normal condition.One of the poly- peptides the large subunit(MW=57000 daltons) of ribulose bisphosphate carboxylase, which is coded for by chloroplast genome and synthesized on 70 S ribosome in chloro- plast,was lost.The photosynthetic intensity is decreased due to the blocking synthesis in chloroplast of some polypeptides which play the important role in photosynthesis.更多还原