山茶科核果茶属和石笔木属的胚胎学研究

EMBRYOLOGICAL STUDIES ONGENERA PYRENARIA AND TUTCHERIA OF FAMILY THEACEAE

观察了短叶核果茶（ＰｙｒｅｎａｒｉａｇａｒｒｅｔｔｉａｎａＣｒａｉｂ），石笔木（ＴｕｔｃｈｅｒｉａｃｈａｍｐｉｏｎｉＮａｋａｉ），粗毛石笔木（Ｔ．ｈｉｒｌａ（Ｈ．－Ｍ．）Ｌｉ））和屏边石笔木（Ｔ．ｐｉｎｇｐｉｅｎｅｎｓｉｓＨ．Ｔ．Ｃｈａｎｇ）的大小孢子和雌雄配子体的发生和发育过程，４个种的胚胎学特征高度相似，均为基本型药壁发育，腺质线毡层，同时型小孢子母细胞胞质分裂，四面体形小孢子四分体，二细胞成熟花粉，倒生胚珠，双珠被，薄珠心，单孢原，蓼型胚囊，卵细胞与助细胞区分明显，均具有珠被绒毡层和承珠盘，以蓼型胚囊区别于邻近的山茶属（Ｃａｍｅｌｌｉａ）。

The species ivnestigated are Pyrenaria garrettiana Craib, Tutcheria championi Nakai,T.hirta(H.-M.)Li and T.pingpienensis H.T.Chang Apart from the number of ovules in each locule,the mega-microsporogenesis and mega-microgatogenesis in all four species are high simi-lar.Embrylogical features shared by these species include:anther tetrasporangiate;anther wall formation of the Basic type;endothecium fibrous,middle layers ephemeral; tapetum glandular,cytokinesis in the microspore mother cell simultaneous; mature pollen grains two-celled;ovules anatropous,bitegmic and tenuinucellate,archesporium one-celled and functioning directly as the megaspore mother celll embryo sac formation of the Polygonum type,egg cell differentiating dis-tinctly from synergids;integument tapetum and hypostase formed.Of these features,the embryo sac formation of the Polygnoum type forms a main difference from the related genus Camellia whose embryo sac formation conforms to the Allium type.