高山红景天胚胎学研究

高山红景天(Rhodiola sachalinensis A.Bor.)具8个雄蕊,每个雄蕊有4个花粉囊。小孢子母细胞减数分裂时,胞质分裂为同时型。形成的四分体为四面体形。花药壁由表皮、药室内壁、二层中层和绒毡层五层细胞组成,其发育方式为基本型。腺质型绒毡层,有些绒毡层细胞分裂形成不规则双层,少数细胞双核。二细胞型花粉。雌蕊由4心皮组成。边缘胎座,倒生胚珠,双珠被,厚珠心,胚珠发育中形成珠心喙。大孢子四分体线形或T -形,合点大孢子具功能。胚囊发育为蓼型。成熟胚囊中,卵细胞核、助细胞核均位于细胞的合点端,珠孔端具液泡;极核融合为次生核,并位于卵细胞合点端附近; 3个反足细胞退化。双受精属于有丝分裂前配子融合类型。胚的发育为石竹型;基细胞侵入珠孔端,形成囊状吸器。细胞型胚乳;初生胚乳核分裂形成两个细胞,其珠孔端的细胞发育成胚乳本体,合点端的细胞直接发育成具一单核的合点吸器。

EMBRYOLOGICAL STUDIES IN RHODIOLA SACHALINENSIS A. BOR

Abstract This paper reported the studies of overall embryology of Rhodiola sachalinensis A.Bor..Development of the anther wall followed the Basic type.Part of the tapetal cells divided into regular two layers.Tapetal cells was uninucleate or binucleate, and blonged to the secretory type.Meiosis of microspore mother cell was normal and cytokinesis was of the simultaneaus type.The tetrad was tetrahedral in shape.The mature pollen grains were 2-celled.The ovule was anatropous, bitegminous, crassinucellate and nucellar beak was formed during the development of the ovule.The megaspore mother cell went meiosis to form a linear tetrad.The chalazal megaspore was functional.The development of the embryo sac was conformed as the Polygonum type.In mature embryo sac, the nuclei of the egg cell and synergids located in the chalazal part of the cells and the microplar part of the cells possessed vacuoles; two polar nucleus fused into the secondary nucleus, and located near the chalazal end of egg cell; three antipodal cells degenerated.The fertilization belonged to the premitotic type of syngamy; the development of the endosporm belonged to the cellular type.The first division of endosperm cell given rise to two cells, the chalazal cell developed into haustorioum without division.The development of the embryo belonged to the Caryophyllad type.In 2-celled proembryo basic cell became much enlarged and formed sacciform haustorium which invade the micropylar.