摘要
成熟橡胶树种子的胚和外胚乳蛋白质含量约占干重的15％。游离氨基酸含量约占干重的0．6％。试验了11种提取液对成熟种子胚和外胚乳蛋白质提取的效果，结果表明，含2％SDS的Tris（41mmol／L）一硼酸（40mmol／L）缓冲液（pH8．6）能提取80％以上的蛋白质。根据SDS－PAGE的结果，这些蛋白质中有两组占优势的组分，笔者称之为组分I蛋白质（36，34和32kDa3种多肽组成）和组分Ⅱ蛋白质（由20．19和18．5kDa三种多肽组成），这两组蛋白质主要存在于种子的外胚乳和子叶中。在种子发育过程中，这两组蛋白质从无到有并大量积累，其进程与光学和电子显微镜下观察到的外胚乳和子叶细胞中液泡蛋白质物质的不断形成基本上是同步的。当种子萌发时，两组蛋白质不断减少，同时外胚乳和子叶细胞液泡蛋白质物质也逐渐消失。因此，这两组蛋白质应当是橡胶树种子的主要贮藏蛋白质，并且可能是外胚乳和子叶细胞中液泡蛋白质物质的主要成分。讨论了橡胶树种子作为顽拗性种于的特点以及橡胶树种子贮藏蛋白质与其营养贮藏蛋白质之间的差别。
The embryo and prosembryum of the mature seed of Hevea brasiliensis contain about 15 % proteins and 0.6 % free amino acids based on dry weight. Eleven extractants for proteins of these tissues were tested and more than 80 % proteins were extracted by the extractant of Tris(41 mmol/L)-Bori acid (40 mmol/L) buffer (pH 8.6) with 2 % SDS. There were two groups of prominent proteins in the polypeptide profiles based on SDS-PAGE. Each group consisted of three distinguishable peptides: 36, 34 and 32 kDa peptides for group I and 20, 19 and 18.5 kDa peptides for group Ⅱ. The two groups of proteins were found mainly in the prosembryum and cotyledon of the seed. During seed development, these proteins emerged and accumulated in a great quantity, which was roughly synchronized with the emergence and increase of the vacuole protein masses in prosembryum and cotyledon cells observed under light and electron microscope. After germination, the proteins diminished continuously, and the vacuole protein masses decreased gradually as well. The results show that Group I and Ⅱ proteins are the major stomp proteins in Hevea seeds and may be the major composition of the vacuole protein masses. The recalcitrant characteristics of Hevea seeds and the differences between the seed storage proteins and the vegetative storage protein in Hevea brasiliensis were discussed.
出处
《热带作物学报》
CSCD
1999年第2期1-10,共10页
Chinese Journal of Tropical Crops
基金
国家自然科学基金!39860066
