籽银桂雌雄配子体的发育研究

Developments of Male and Female Gametophytes of‘Ziyingui’, an Osmanthus fragrans Variety

利用石蜡切片和扫描电子显微镜技术,研究了南京地区银桂品种群的籽银桂雌雄配子体的发育过程.雄蕊的孢原细胞在8月中旬出现.花药壁的发育为基本型,分泌型绒毡层.小孢子母细胞减数分裂为同时型,形成的4个小孢子四分体呈典型的四面体型.成熟花粉粒即雄配子体为二核花粉粒.籽银桂为倒生胚珠,单珠被,薄珠心. 珠被内层细胞特化为珠被绒毡层.在胚珠合点端,有承珠盘结构.在9月中旬,雌蕊的孢原细胞开始分化出来.孢原细胞直接发育成大孢子母细胞,然后大孢子母细胞减数分裂形成大孢子. 籽银桂的胚囊发育类型为蓼型.成熟胚囊即雌配子体由2个助细胞、1个卵细胞、1个中央细胞2个核和3个反足细胞组成.

Paraffin sectioning and electron microscope scanning were adopted to study the developments of male and female gametophytes of ‘Ziyingui’, an Osmanthus fragrans variety belonging to Osmanthus fragrans var. latifolius community distributing in Nanking. The archesporium in its stamen appeared in the middle ten days of August. Its anther had fundamental cell wall forms and secretary tapeta. Ziyingui had anatropous ovules with single layer integument and thin nucelli. Inner cells in the integument differentiated into integument tapeta. There were hypostases at the chalazal end. In the ten days of September, The archesporium began to differentiat in its pistils. The archesporium in its pistils directly developed into megaspore mother cells, which later divided into macrospores through meiosis. The development of embryo sacs of ‘Ziyingui’ belonged to polygonum type. Mature embryo sacs, i.e. female gametophytes, consisted of two synergids, one oocyte , one central cell(with two nuclei) and three antipodal cells.