Abstract:

The ultrastructural characteristics and the subcellular localization of vegetative storage proteins (VSPs) of Ginkgo biloba L. were systematically studied under the electron microscope. Results indicated that the VSPs of G. biloba were mostly distributed in the small vacuoles of the phloem parenchyma cells. The VSPs of phloem parenchyma cells were produced in cytoplasm, then separated by the inflated cisternae of endoplasmic reticulum (ER), plasmalemma invagination or Golgi body vesicles, resulting in the formation of vacuole filled with proteins. Three kinds of VSPs were detected: granular, floccular and massive VSPs, which were distributed in different tissue cells and different cells of the same tissue or vacuoles of the same cells. VSPs accumulated in autumn and kept at high level throughout the winter. In the following spring, the bud started growing and VSPs were completely mobilized. With new shoots growth, VSPs resumed accumulating in late summer and early autumn.

Key words: Ginkgo biloba , vegetative storage proteins (VSPs), nitrogen storage, ultrastructure