| 篦子三尖杉的胚胎学研究及其系统位置的探讨 |
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| 引用本文： | 李莹,王伏雄,陈祖铿.篦子三尖杉的胚胎学研究及其系统位置的探讨[J].中国科学院研究生院学报,1986,24(6):411-422. |
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| 作者姓名： | 李莹 王伏雄 陈祖铿 |
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| 作者单位： | (中国科学院植物研究所，北京) |
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| 摘 要： | 篦子三尖杉Cephalotaxus oliveri的成熟花粉包含两个细胞，花粉管在精原细胞产生后 经历了一年的休眠期; 精原细胞分裂产生两个体积不等的精子; 雌配子体游离核经12次分裂后形成细胞壁; 窄长的颈卵器单个顶生; 卵细胞中含有大量类核仁状体; 受精时，雌雄核在分裂中期完全融合; 原胚游离核在16核时产生细胞壁; 原胚具冠细胞; 无裂生多胚现象; 成熟胚 二枚子叶。总之，蓖子三尖杉与本属其它种相比，存在明显的差异。如精原细胞分裂前细胞中心细 胞质浓缩成星状放射区域; 苗端早在胚成熟前分化形成明显的突起，以及成熟胚的子叶极为发达等等。因此，作者赞同将蓖子三尖杉在本属中另立一组的观点。
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| 关 键 词： | 三尖杉属 胚胎发育 系统发育 |
An Embryological Investigation and Systematic Position of Cephalotaxus oliveri Mast. |
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| Li Ying,Wang Fu-Hsiung,Chen Zu-Keng.An Embryological Investigation and Systematic Position of Cephalotaxus oliveri Mast.[J].Journal of the Graduate School of the Chinese Academy of Sciences,1986,24(6):411-422. |
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| Authors: | Li Ying Wang Fu-Hsiung Chen Zu-Keng |
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| Institution: | (Institutc of Botany, Academia Sinica. Beijing) |
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| Abstract: | The tapetum is of the secretory type. After breakdown of callose wall around
tetrads, tapetal cells degenerate quickly and disappear completely at the late stage of micros-
pore development. The mature male gametophyte is of a tube cell and a generative cell, with-
out prothallial cells. The pollen tube lodging in the nucellus contains a spermatogenous cell, a
tube nucleus and a sterile cell before entering domancy. In the following spring the pollen
tube grows fast, and reachs the female gametophyte when the archegonia are mature. The sper-
matogenous cell enlarges obviously, and the cytoplasm is very dense in the centre of the cell
and shows well-marked radiations from this region to the periphery, when it divides to form
two sperm cells of unequal size, while the tube nucleus and the sterile cell degenerates and sub-
sequently disappears. After 12th simultaneous divisions the cell wall of the female gametophyte
forms from the periphery to the centre. When the central cell has divided to form the egg and
the ventral canal nucleus ,its cytoplasm becomes very dense and numerous bodies, similar to nu-
cleoli in appearance, occurs. The sperm and the egg come together at metaphase of the first
division of the zygote. The wall formation of proembryo initiates at the 16-nucleate stage.
The features of the mature embryo are as follows: (a) The cotyledons are very long, with
their length about four fifths of that of the whole embryo, (b) the embryonal axis is so short
as to cover only about one sixth of the cotyledons, (c) there is no typical pith, (d) the root cap
is well-developed and consists of about 10-15 layers of cells which are very large and are full
of starch grains and (e) the epidermis cells only extend to the upper part of the root cap. It
is concluded that Fu's (1984) suggestion, that the Cephalotaxus be divided into two sections, Ce-
phalotaxus and Pectinatae, is supported by the present embryological investigation on C. oliveri. |
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| Keywords: | Cephalotaxus Embryology Phylogeny |
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