J Integr Plant Biol. ›› 1960, Vol. 9 ›› Issue (2): -.

• Research Articles •    

The Early Embryogeny of Keteleeria

F. H. Wang and L. F. Yang   

Abstract: The life history of Keteleeria evelyniana Mast. has been studied as early as 1939 and since then two articles have been published elsewhere by the senior author. The present investigation deals with the early embryogeny of the species in question. The material was collected in 1957 in the suburb of Kunming. Based upon the observations of both dissected and sectioned preparations, the following results are obtained: 1. The pollen tube discharges its contents including the sperms and other nuclei into the same archegonium. 2. The ventral canal cell is intact during the penetration of the pollen tube. 3. The size of the sperms is variable and the two sperms are either equal or unequal in size. 4. The organization of the proembryo is the same as that of Pinus, namely: it consists of four tiers of four cells each. 5. As soon as the suspensor tier elongates to a certain length, the suspensor is reinforced by the embryonal tubes (secondary suspensor) derived from the posterior end of the embryo proper. Usually 5–6 segments of embryonal tubes are formed in succession before cleavage occurs. Cleavage may take place much earlier in some deviated embryos. 6. Polyembryony is a constant feature during the early embryogeny and the embryos are derived from the following sources: (1) fertilization of more than two archegonia in the same ovule; (2) cleavage of the embryo and (3) formation of the suspensor embryos. 7. Rosette cells divide very rarely. 8. Four phases of embryogeny in Keeleeria are divided as follows. (1) proembryo phase; (2) phase of embryonic selection; (3) phase of embryonic organogenesis; (4) phase of embryo maturation. The possible application of the scheme to other conifers is proposed.

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