巴西橡胶树初生乳管黄色体微纤维蛋白质与67kD蛋白质的关系

在古铜期的巴西橡胶（Hevea brasiliensis Mull.Arg)幼茎初生乳管黄色体中存在丰富的微纤维蛋白质。在电子显微镜下，微纤维蛋白质呈两种不同的形态，分别存在于不同的黄色体中，SDS-PAGE分析表明，经等电点纯化的微纤维蛋白质的主要成分是59.5kD和63.5kD蛋白质，使用67kD蛋白质的抗血清的免疫印迹表明，59.5kD和63.5kD蛋白质与积累在贮藏蛋白质细胞中的67kD蛋白质具有一定程度的免疫相关性，且在苗生长发育过程中互为消长，59.5kD和63.5kD蛋白质在古铜期的幼茎中最丰富，当新梢茎停止伸长及叶片刚成熟时，其含量略有降低，但在第二和第三伸长单位中明显消失，同时在黄色体中大量积累3-5种低分子量蛋白质。这种季节变化模式表明，59.5kD和63kD蛋白质的消失与新梢的伸长生长无关，与初生乳管的发育关系密切，67kD蛋白质在古铜期的幼茎中不存在，随着新梢的成熟，该蛋白质不断积累，表现为典型的营养贮藏蛋白质。

Fluctuation of Microfibrillar Protein Level in Lutoids of Primary Laticifers in Relation to the 67 kD Storage Protein in Hevea brasiliensis

Abundant microfibrillar protein inclusions were present in the lutoids of the primary laticifers in Hevea brasiliensis Mull. Arg. Two forms of the inclusions could be distinguished under the electron microscope, each in separate lutoids. As revealed by SDS_PAGE, the 59.5 kD and 63.5 kD proteins were the major components of the microfibrillar protein purified by isoelectric point precipitation. Western_blotting analysis indicated that they were immunorelated with the 67 kD protein accumulated in the protein_storing cells. The 59.5 kD and 63.5 kD proteins were abundant in the uppermost part, the stem of new shoot and sustained their abundance during the growth and development of new shoot while their contents decreased remarkably in the lower parts of the trunk, accompanying by the accumulation of 3-5 kinds of proteins with low molecular weights. This fluctuating pattern suggested that the degradation of the 59.5 kD and 63.5 kD proteins had nothing to do with the new shoot growth and may be closely related to the primary laticifer differentiation. The 67 kD protein could not be detected in the young stem of new shoot when its leaves were broze_colored while the protein started to be accumulated in the stem when the leaves of new shoot had matured, behaving like a typical vegetative storage protein.