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Journal of Systematics and Evolution ›› 2000, Vol. 38 ›› Issue (4): 337-342.

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CHEN Xiao-Lin, LI Ming, YOU Rui-Lin   

  • 出版日期:2000-07-10 发布日期:2000-07-10

A study on the development of stigma and megagametophyte, and embryogeny in Cimicifuga simplex Wormsk

CHEN Xiao-Lin, LI Ming, YOU Rui-Lin   

  • Online:2000-07-10 Published:2000-07-10

Abstract: This is one of a series of studies on the reproductive features in Cimicifuga nanchuanensis Hsiao, an endangered plant endemic to China, and C. simplex Wormsk, a closely related and widely spread species as a control. The present paper deals with the results of cyto-morphological observations on the megasporogenesis, the development of female gametophytes, and the embryogeny in C. simplex. Its anatropous ovules are bitegminous and crassinucellate. A megaspore mother cell undergoes meiosis to form a linear or T-shaped megaspore tetrad. The embryo sac is of Polygonum type. The three antipodal cells persist up to the globular stage of embryo development.Two polar nuclei fuse to form a secondary nucleus close to the chalazal end of the embryo sac and connect with antipodal cells before fertilization. The development of endosperm is of Nuclear type. Cellularization of nuclear endosperm initiates since early globular stage of the embryo development. Development of the embryo in C. simplex is of Onagrad type. C. simplex is dichogamous. Stigmatic papillae emerge on the 1st∽2nd day and they elongate into stigmatic hairs on the 3rd∽5th day after stamens withering. The great impact of the differences of the receptible period of stigmas and pollen viabilitybetween the two species on effective pollination and seed-setting rate is discussed.

Key words: Cimicifuga simplex Wormsk, Megasporogenesis, Female gametophyte development, Embryogeny, Stigma deveolopment