• Journal of Ginseng Research
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• v.16 no.1
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• pp.31-36
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• 1992

The ultrastructural changes and differentiation mechanism of chromoplasts and leucoplasts from Proplastids in root tip cells of Panax ginseng seedlings were studied with transmission electron microscope. Initial cells have so many proplastids with a few osmiophilic droplets and a lot of mitochon dria at early stage of germination, therefore electron density of cytoplasm is generally higher than that of the other cells just like periblem, plerome and root cap. Proplastids are observed in the initial cells, but only leucoplasts appeared in the central root cap cells. Because root cap cells are derived ultimately from initial cells, the cell organelles in the root cap cells are directly related by those of initial cells. This result postulates that leucoplast is diferentiated from proplastid, and this is the same with other's concepts. On the contrary, the precise observations of chromoplast with crystalline inclusions in the peripheral root cap cells can conclude the direct pathway of chromoplast development from proplastid. Because of the differences of these result from those of other experiments, new scheme of plastid development, direct differentiation of chromoplast from proplastid, can be postulated. And this is the originality of this research on the differentiation of plastids.

• Horticultural Science & Technology
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• v.30 no.2
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• pp.107-122
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• 2012

In plants, color is a powerful tool to attract insects and herbivores which act as pollinators and vehicles of seed dispersion. In particular, flower color has held key post for human with aesthetic value. Horticultural industry has developed methods to produce new and attractive color varieties in flowering plants. Carotenoids are one of the main pigments being responsible for red, orange, and yellow colors. Their biosynthetic pathway has been considered as a major target of metabolic engineering for color modification of flowers and fruits. Here, we review the diverse efforts to modify pigment phenotype by the control of carotenogenic gene expression and enzyme levels. Recent reports about regulating degradation and storage of carotenoids will be also summarized to help the creation of engineered flower with novel color phenotype which is not existed in nature.

• Applied Microscopy
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• v.10 no.1_2
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• pp.77-86
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• 1980

The distribution of the secretory ducts, fine structures of the secretory epithelial cells, and the ingredients of the metaplasmic inclusions were studied at light and electron microscopical levels in seeds, stems, leaves, and roots of ginseng. The secretory ducts occurred in the hypocotyl of the embryo, in the cortex of the roots, and also both inside and outside of each vascular bundle in the stems and leaves. Especially, it is considered that the circular layers of the secretory ducts in roots may represent their ages. The epithelial cell has well developed nucleolus, mitochondria and smooth endoplasmic reticulum. Sudanophyl and osmiophilic inclusions were found in the epithelial cytoplasm and duct lumen. But these inclusions were not observed when extracted with pyridin or alcohol. In contrast to the lumen with red color, the epithelial cells were blue in color as stained with nile blue, suggesting that the former inclusions are neutral lipid while the latter are acidic lipid. The electron density of the cell inclusions was quite high as fixed with osmium tetroxide, indicating that most of these secretory materials seem to be unsaturated lipid. Therefore, since ginseng secretory ducts are closely associated with the lipid metabolism, it should be called lipid canal or lipid duct.