Embryological Studies on Endangered Ophiopogon xylorrhizus (Liliaceae)

HE Tian-Hua, RAO Guang-Yuan, YOU Rui-Lin, ZHANG Da-Ming

Received:1900-01-01 Revised:1900-01-01 Online:1998-07-10 Published:1998-07-10
Contact: HE Tian-Hua

Abstract:

The embryological studies on an endangered species Ophiopogon xylorrhizus are

reported in this paper. The anther was four-sporangiate, and its wall was composed of four

layers: epidermis, fibrous endothelium, middle layer and glandular tapetum. Cytokinesis of

microspore mother cell in meiosis was of the Successive type, and tetrads were tetrahedral or

isobilateral. The mature pollen grains were 2-celled. Ovules were anatropous, bitegminous,

and crassinucellate. Ovary wall ruptured 4～5 days after fertilization. The development of

embryo sacs conformed to the Polygonum type. The two polar nuclei fused into a secondary

nucleus before fertilization. The embryogeny was of the Asterad type, and endosperm devel-

opment corresponded to the Nuclear type. About 55.8 % individuals in the population of O.

xylorrhizus were found male sterile, and 43.3% of embryos aborted at early development

stage. As a conclusion, we consider that (1)the failure of the xenogamy resulted from male

sterility, autogamy and inefficient pollination agents, (2)embryo abortion and (3)exposure

of young seeds during their early development are the weak links in the sexual reproduction

of O. xylorrhizus, which would contribute to the endangerment of this species.

Key words: Ophiopogon xylorrhizus, Gametophytic development, Fertilization, EmbryoDevelopment, Endangered Plant

HE Tian-Hua, RAO Guang-Yuan, YOU Rui-Lin, ZHANG Da-Ming. Embryological Studies on Endangered Ophiopogon xylorrhizus (Liliaceae)[J]. .

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