全 文 ：广 西 植 物 Guihaia 22(3)：249— 251 2002 年 5月
“ 藏茵陈’ 川西獐牙菜的大孢子
发生及雌配子体发育
薛春迎 ，何廷农 ，李德铢
(1．中国科学院昆明植物研究所 ，云南昆明 650204；2．中国科学院西北高原生物研究所 ，青海西宁 81 0001)
摘 要 ：首次报道 了藏茵陈川西獐牙菜 的大孢子发生及雌配子体发育。川I西獐牙菜 为倒生胚珠 ．薄珠心．单
珠被．线形大孢子四分体 ．胚囊发育为蓼型．反足细胞分裂为 5～8个 ．宿存．每个细胞均异常膨大．并多核。反
足细胞在龙胆科一些一年生高山植物中的宿存和分裂具有重要的生殖适应和进化意义 ．这对 于这些植物在
青藏高原严酷的自然环境下 ，在短时间内完成其生活史是非常重要的。
关键词：川I西獐牙菜 ；大孢子发生 ；雌配子体发育；“藏茵陈”
中图分类号 ：Q944 文献标识码 ：A 文章编号 ：l000 31 42(2002)03—0249-03
’- ‘ 1 n 一 · 1 Nlegasporogenesis and temale gam etogenesis deve-
l opment of the Tibetan m edicine “Zang Yin
Chen ’ wert la muSSot ll Gentianaceae) ，1 ．■ ．●●／ ·■ ＼
XUE Chun—ying 。 。，HE Ting—nong ，LI De—zhu
(1．Kunming lnstitute of Botan3，，Chinese Academay oJ Sciences．Kunming 650204．China：2．^ ，一thz “Plat ““
lnstitute oJ Biology，Chinese Academ3，of Sciences，Xining 810001，China)
Abstract：The present paper firstly reports the development of megasporogenesis．female gametophyte in Swer—
tia mussotii，a famous Tibetan medicine．The ovule is anatropus．tenuinucelate．initegmic．the megaspore tetrad
is linear and embryo sac development is of the Polygonum type．TEe three antipodal cels can be divided into 5～
8 cels with enlarged and polyploid nuclei．The dividing and persisting of the antipodal cels in alpine annual Gen—．
tianaceae plant are of significance in reproductive adaptation and evolution．which is important for those
ephemeral species of Gentianaceae to complete their life cycle under the arid surrounding of Qinghai—Xizang
plateau within a few weeks’growing season．
Key words：S．mussoti；megasporogenesis；female gametophyte；Tibetan medicine；“Zang Yin Chen’
Swertia mussoti(Gentianaceae)，an effective Ti—
betan medicine tO cure liver disease，is mainly dis—
tributed in the Qinghai—Xizang Plateau，with a cold
climate and short growing season．The annual species
complete their life cycle within a few weeks in this
arid surrounding．It is a mystery why and how these
收稿 日期：2001—03—01
作者简介：薛春迎(1969一)，女 ，河北威县人 ，博士 ，现在中国科学院昆明植物所博 士后流动站工作 ，研究方 向：植物系统与进化生物学。
基金项目：中国科学院分类区系学科特别支持费资助项 目
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250 广 西 植 物 22卷
plants acquire their reproductive adaptations to the
plateau and normally produce their offspring． This
ephemeral species relies on the seeds to reproduce in
natural conditions．But during the propagation of this
species，it is difficult to germinate seeds．
The present paper reports the ovary of S． ?nUS—
soti for investigating its reproductive pattern and
adaptation to the Qinghai—Xizang Plateau．
M aterial s and M ethods
Materials investigated for the present study were
collected from Yushu．Qinghai province，China．The
voucher(I iu Jian—quan)is deposited in the Herbarium
of Nort hwest Plateau Institute of Biology，Chinese
Academy of Sciences，China(HNW P)．
Ovules at,different stages of development were
fixed in the formalin—acetic—alcohol(FAA)．After be
ing stained in Ehrfich’s hematoxylin， the material
w-as embedded in paraffin by the conventional method
and sectioned at the thickness of 5～ 1 0／zm，sections
were stained with safranin—fast green． ()bservation
and photographs were taken under Olympus BH2 mi—
croscope．
2 Observations and Resul ts
2．1 M acrosporangium and macr0sp0r0gensis
The ovary was superior，bicarpelary， syncar—
pous and unilocular with parietal placentae． There
were 8 rows of ovules in the transection of ovary
(Fig．1 0)．The integument initiated by periclinal and
oblique division at the base of nucelus．The ovule of
S．nlUSSotii is unitegmic．The integument reached the
top of nucellus and formed a micropyle by continued
division．The type of ovule is anatropous．
At the stage of microsporocyte，a single hypo—
dermal archesporial cell differentiated in the young
nucellus and functioned directly as the megasporocyte
(Fig．1)which was characterized by a large nucleus
and dense cytoplasm．Thus，the ovule of S．mussoti
was tenuinucellate． The megasporocyte underwent
meiosis，forming a linear tetrad of megaspores(Figs．
2、3)． The three micropylar megaspores eventually
degenerated，while the chalazal one became functional
(Fig．4)．
2．2 Embryo sac and fem al e gametophyte
A 7-ceils and 8一nucleate female gametophyte of
the Polygonum type formed by three meiosis divisions
of the functional megaspore (Figs．5、6)． The three
micropylar nuclei became the egg and the two syn—
ergids．they consisted the egg apparatus(Figs．7、8)．
The two nuclei became the polar nuclei．The chalazal
nuclei became the three antipodals．The polar nuclei
fused at the center and the resuhed secondary nuclens
then moved close to the egg apparatus(Fig．8)．
In the mature 8-nucleate embryo sac，the egg
cell was recognized by nucleus at the chalazal end and
a large vacuole at the micropylar end；the two syn—
ergids(Figs．7～ 8)were recognized by their nuclei at
the micropylar end and a large vacuole at the chalazal
end．
2．3 Antipodal cel Is
Three antipodal cels of S． mussotii were not
ephemeral as observed in most angi’osperms 。．They
persist at the mature embryo sac stage． Afterward，
three cells divide into 5-8 cells with enlarged and mul—
tiseriate nuclei and persist like a layer of“out en—
dosperm”around embryo sac(Fig．9)
3 Discussion
(1)The present study reveals the annual S．?YlUS—
sotii with persistent and secondly multiplication an—
tipodal cells，which may account for it speedy seeds
development under the arid surrounding of the Qing—
hat—Xizang Plateau． The time’s span in S． mussotii
between flowering to shedding seed amounts to no
more than 20 days．It is easy for it to produce normal
seeds and complete recruitment of offspring in spite of
short growing season in the arid habits of the
plateau．Akhalkatsi and W agner ” found similar re—
sults in the arid Alps．mountain，that the persistent
antipodal cels of the annual gentiana accelerate the
embryogensis and shorten the time of seed develop—
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3期 薛春迎等 ：“藏茵陈”—— 川西獐牙菜的大孢子发生及雌配子体发育 251
ment． Because of the short growing season， the
ephemeral plants in the alpine mountains must acquire
some peculiar traits to help them to complete their life
histories within such short time．As for Gentianaceae
plants，most annual species have persistent antipodal
cells to help them accelerate seeds developing‘。～ ．It
might be one of reasons why so many ephemeral Gen
tianaceae species distributed widely on the arid moun—
tains especialy on the arid Qinghai—Xizang Plateau．
The dividing and persisting of the antipodal cells in
alpine annual Gentianaceae plants are of significance
in reproductive adaptation and evolution， which is
important for those ephemeral species of Gentianaceae
to complete their life cycle under the arid surrounding
of Qinghai—Xizang Plateau within a few weeks’grow—
ing season．
(2) As regards the embryological features of
Swep‘f s．1．，there are eight species(5．carohnesis，
S．cot3 l~2obosa，S．angustifcdia，S．171i1101 ，S．ibo ica
S． anchetiana， S． erythp osticta， S． tetrapte,‘
a，) 。～ concerning to earlier reports and recent stud—
ies．The resuhs show that these species of Swertia s．
1．share the folowing ovary characters：tenuinucel—
late，with a single integument，the megaspore tetrad
is linear，embryo sac development is of the Polygon—
um type． The abovementioned features have been
found in S．mussoti．
Acknowledgment：This research was supported
by a grant for systematic and evolutionary biology
(Chinese Academy of Sciences)．The authors express
sincere thanks to Dr．Liu Jian—quan for his help in
collecting the materials．
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Expl anation of PI ates
Ant，antipodal cel1．DM ，Degenerating megaspore．E，Egg，SN ，Secondary nucleus，Sy，Synergid．
Fig． 1．A unitegmic ovule and megasporocyte；2．Anaphase I of meiosis in megaspoRocyte；3． I．inear megas—
pore tetrad；4．The functional chalazal megaspore，with other three degenerating．A one—nucleate embryo sac
and showing the other three degenerated megaspores；5．The two—nucleate embryo sac；6．The four—nucleate
embryo sac；7～ 8．consecutive transactions of an eight—nucleate embryo sac，showing an egg，two synegids，
and secondary nucleus；9．The mature embryo sac stage showing 5-8 antipodal cells；1 0．Transverse section
showing eight rows of ovules(1-3× 768，4-8× 684，9× 1 168，10×136)．
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