J Integr Plant Biol. ›› 1981, Vol. 23 ›› Issue (4): -.

• Research Articles •    

Late Embryogeny of Fokienia

Chen Zu-keng and Wang Fu-hsiung   

Abstract: The young embryo of Fokienia became massive and columnar in the middle of July in Chekiang, China. The polarity of the embryo has already been evident at this time. The cell in the free apex of the columnar embryo are smaller, while in the opposite end the cells continuous to the suspensor are larger in size and irregular in arrangement. Then a group of root initials appears at the middle part of the arc formed by the arrangement of the cells about 10 cells deep from the free apex. All kinds of tissues and organs of the embryo were differentiated in the first week of August. And the root initials become evident. Finally the root initials give rise to the procambium and the embryonic cortex upward and the root cap downward. There are about 20 layers of cells of the procambium in width and only about 10 layers of cells in cotyledonal procambium strand in the mature embryo. The cells of the embryonic cortex are continuous to those of the pericolumn of the root cap. The embryonic epidermis is absent in root cap. The embryo became fundamentally mature about the end of September. The hypocoty and cotyledons are well developed and each constitutes about 40% of the total length of the mature embryo. The root cap is rather weak, only about 10% of the total length. And the rest is the degenerated suspensors. The pith and secretory cells are absent in the mature embryo. The cotyledonal number of the embryo is 2. In mature ovule, there are 15 layers of nucellar cells in width in micropylar part but only 4—5 layers around the rest of the female gametophyte. The megaspore membrane is about 3.6μin thickness. When the young embryo is in the columnar stage, the nuclei of the female gametophytic cells are dividing and forming polynucleate cells. Thus, each cell usually has 2—4 nuclei. In this case, the cells of female gametophyte are large and isodiametric and about 60—120 μ in diameter. But the cells in the outer layer of the female gametophyte are rather small and they are usually uninuclear, rarely binuclear. The present article also deals with the starch distribution during the late embryogeny.

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