中文摘要：

蛋白质组学研究的瓶颈问题之一是低丰度蛋白的检测，这些低丰度蛋白往往发挥多种重要的生理功能，如细胞防御、基因表达调节、信号传导等，因此低丰度蛋白的检测尤为重要。在双向电泳试验时，有2个因素限制了低丰度蛋白的检测：第一，IPG胶条的上样量有限；

英文摘要：

Magnolia sieboldii seeds store large amount of proteins that would interfere with determination of low abundance proteins by the electrophoresis pattern. In this study, a plant leaf protein extraction method was employed, that is, enriching high-abundance protein Rubisco by PEG. The PEG fractionation method was compared with TCA-acetone extract method in 2-DE analysis of protein samples. The result showed that the two methods had good reproducibility for extracting proteins. High-abundant proteins were precipitated predominantly in the 8% and 16% PEG fraction. With this protocol, a total 1 770 protein spots were detected, among which 50% of proteins were undetectable with the TCA-acetone method. With the PEG fractionation method, low-abundance protein detection rate increased significantly, and the PEG fractionation method, as a new method for proteomics study of M. sieboldii seeds, would be able to satisfy the follow-up test in screening the seed germination associated protein needs. The PEG fractionation method would also provide a reference for other plant seed proteins extraction.