Ostrya virginiana (Betulaceae)的胚珠和胚囊发育及其系统学意义

中国科学院大学学报

Ostrya virginiana (Betulaceae)的胚珠和胚囊发育及其系统学意义

邢树平,陈之端,路安民

收稿日期:1900-01-01 修回日期:1900-01-01 出版日期:1998-09-10 发布日期:1998-09-10
通讯作者: 邢树平

Development of Ovules and Embryo sacs in Ostrya virginiana (Betulaceae) and Its Systematic Significance

XING Shu-Ping, CHEN Zhi-Duan, LU An-Ming

Received:1900-01-01 Revised:1900-01-01 Online:1998-09-10 Published:1998-09-10
Contact: XING Shu-Ping

摘要/Abstract

摘要：

首次报道了铁木属Ostrya的胚珠和胚囊发育过程。研究结果表明: O. virginiana的多数子房

内有2个胚珠，胚珠倒生，单珠被，厚珠心，具1至数个孢原细胞；孢原细胞子周分裂形成一个周缘细胞

和一个造孢细胞，造孢细胞直接发育成大孢子母细胞，四分体大孢子呈线形排列，它们均可成为功能大

孢子；绝大多数胚珠中具2～6个胚囊，胚囊蓼型。最后，对珠被层数和多孢原、多胚囊等问题进行了讨

论，并对桦木科各属的胚胎学性状作了比较，发现桦木科各属的胚胎学特征具有较高的一致性，如多孢

原、多胚囊，较长的传粉和受精间隔期等。同时，比较和讨论了某些胚胎学性状，如胚珠类型和珠被层

数，在高等金缕梅类各科间的异同及系统学意义。

关键词: Ostrya virginiana, 胚珠, 多孢原, 多胚囊, 系统学意义

Abstract:

The development of ovules and embryo sacs in Ostrya virginiana was studied for

the first time. Most ovaries had two ovules which were anatropous, unitegmic and crassinu-

cellate. The ovule usually possessed several archesporial ceils which divided periclinally into

the upper parietal cell and the lower sporogenous cell. The sporogenous cell functioned di-

rectly as megaspore mother cell. The tetrad of megaspores was linear in arrangement, and

every megaspore might be functional. One ovule often contained 2- 6 embryo sacs and the

embryo sac belongs to Polygonum type. It can be concluded from the present data that all

ovules among the genera of the Betulaceae are unitegrnic. There are more groups with the

phenomenon of multiple embryo sacs in anemophic plants such as Betulaceae, Casuarinaceae,

Graminae, Jnglandaceae, Myricaceae, Simaroubaceae, Ulmaceae, than in entomophilous

plants. Multiple embryo sacs also occur among some parasitic plants and saprophytes, e.g.

Orobanchaceae, Cassytha in Lauraceae, Cuscuta in Convolvulaceae and Utricularia in Len-

tibulariaceae. It may be inferred that the characteristic of multiple embryo sacs be an evolu-

tionary adaptation of those plants with lower pollination rate to increase the rate of fertiliza-

tion. Finally, a comparison of embryological characters among the genera of the Betulaceae

shows that the family is of a number of common embryological characters, such as multicellu-

lar archesporium, multiple embryo sacs in one ovule, and a long interval between pollination

and fertilization. The diversity and systematic significance of several embryological characters

among the “higher” hamamelid families are also discussed. It is still hard to explain the phy-

logenetic relationships among those families clearly only with.

Key words: Ostrya virginiana, Ovule, Multicellular archesporium, Multiple embryo sacs

邢树平,陈之端,路安民. Ostrya virginiana (Betulaceae)的胚珠和胚囊发育及其系统学意义[J]. 中国科学院大学学报.

XING Shu-Ping, CHEN Zhi-Duan, LU An-Ming. Development of Ovules and Embryo sacs in Ostrya virginiana (Betulaceae) and Its Systematic Significance[J]. .

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