全 文 ：武汉植物学研究 2001, 19 (3) : 187～ 190
J ourna l of W uhan B otan ica l Resea rch
珍稀水生植物——宽叶泽苔草的核型研究
王　勇　 王青锋Ξ 　Gitu ru W. Robert　 郭友好
(武汉大学生命科学学院植物系统与进化生物学实验室, 武汉　430072)
摘　要: 宽叶泽苔草 (Cald esia g rand is Sam uel. )是一种珍稀濒危水生植物。它曾经一度被认
为已经从中国大陆灭绝, 但最近又在湖南省的一个高山沼泽中被发现。本文首次报道了依据
上述新发现地点的宽叶泽苔草材料进行的细胞学研究结果。核型分析结果表明: 本种染色体
数目为 22, 其染色体组型高度不对称。结合前人对宽叶泽苔草一些近缘种的细胞学及古生物
学研究结果, 作者认为泽苔草属植物很可能是泽泻科中最进化的一个属。
关键词: 泽泻科; 泽苔草属; 宽叶泽苔草; 核型
中图分类号: Q 942. 4　文献标识码: A 　文章编号: 10002470X (2001) 0320187204
Karyotyp ica l Stud ies on Ca ldes ia g rand is Sam uel. , A Rare
and Endangered M arsh Plan t in Ch ina
W AN G Yong, W AN G Q ing2FengΞ , G ITU RU W. Robert, GUO You2H ao
(L abora tory of P lan t S y stem a tics and E volu tionary B iology , Colleg e of
L if e S ciences, W uhan U niversity , W uhan　430072, Ch ina)
Abstract: Ca ld esia g rand is Sam uel. is an endangered aquat ic p lan t w h ich w as
once con sidered to be ex t inct in m ain land Ch ina and w as recen t ly found in a
bog in a moun ta inou s region of H unan P rovince. A cyto logica l study on the
species basing on the m ateria ls from the new ly found locality is repo rted here.
T he karyo typ ica l analysis reveals tha t th is species has a ch romo som e num ber
of 22 and con ta in s h igh2level asymm etrica l ch romo som al comp lem en ts. Com 2
b in ing the resu lts of cyto logica l and paleon to logica l studies on som e clo sely re2
la ted species repo rted by earlier researchers, it is suggested here that the genu s
Ca ld esia is p robab ly the mo st advanced group in A lism ataceae.
Key words: A lism ataceae; Ca ld esia; C. g rand is; Karyo type
T he genu s Ca ld esia belongs to the fam ily A lism ataceae. Among the 11 genera in
A lism ataceae, Ca ld esia is con sidered to be an impo rtan t group w ith un ique taxonom icΞ 收稿日期: 2000210210, 修回日期: 2000212222。基金项目: 国家自然科学基金项目 (项目编号: 39770055)和教育部骨干教师项目资助课题。作者简介: 王勇 (1974- ) , 男, 博士生, 从事植物系统与进化研究。通讯作者。
characters u sefu l in the classi2
f ica t ion w ith in the fam ily [1 ].
T he genu s con sists of on ly 3
species (o r som etim es 4 spe2
cies, as C. p a rnassif olia has
been sp lit in to 2 species by
som e bo tan ists ow ing to the
h igh degree of variab ility in
their mo rpho logy [2 ] ) and its
d ist ribu t ion is basica lly sub tro2
p ical. A ll the th ree species in
the genu s are rela t ively uncom 2
mon in their occu rrence w ith C.
g rand is Sam uel being the mo st
narrow ly dist ribu ted one (F ig. 1).
Som e localit ies w here C. g rand is has been p reviou sly reco rded have been found no t to
have any individuals grow ing at p resen t. T here are on ly 5 herbarium specim en s of C.
g rand is altogether in Ch ina. T he au tho rs have visited H efeng, from w here the 4 speci2
m en s of C. g rand is in W H w ere co llected in 1985. N o individual of the species w as found
in the locality after a 32day long in ten sive search. L iu Kem ing et a l. have invest iga ted the
locality of a specim en of C. g rand is held in BJ. and no individuals w ere found there
too [3 ]. C. g rand is w as believed to be ex t inct in m ain land Ch ina un t il the finding on M ang2
shan M oun ta in in 1997 by L in Q i[3 ]. T he species is con sidered as endangered in Ch ina
and has already been listed in the Ch ina R ed D ata Book of Endangered Species of
P lan ts[3 ]. T he situa t ion is rendered mo re u rgen t by the fact tha t ou r know ledge of the b i2
o logy of th is rare p lan t is inadequate and the research w o rk done on it is by far m uch less
than that done on the o ther tw o species in the genu s[1, 4 ]. In th is paper, the karyo type of
C. g rand is is repo rted fo r the first t im e and its taxonom ical sign if icance is d iscu ssed in
comparison w ith o ther clo sely rela ted species.
1　M a ter ia ls and m ethods
T he p lan ts of C. g rand is w ere co llected from M angshan, H unan P rovince of Ch ina
and cu lt iva ted in po ts in the garden of ou r labo ra to ry in W uhan U n iversity. Roo t t ip s fo r
karyo typ ica l ob servat ion s w ere ob ta ined from the p lan ts in cu lt iva t ion and the voucher
specim en s w ere depo sited in W H.
Ch romo som e ob servat ion s w ere m ade from roo t t ip s p retrea ted in a m ix tu re of sa tu2
ra ted aqueou s so lu t ion of paradich lo ro2benzene and a lit t le amoun t of b romonaph thalene
fo r 4 hou rs; then sta ined by the H eiden2hain s iron2alum haem atoxylin m ethod after hy2
881 武 汉 植 物 学 研 究　　　　　　　　　　　　　　　　　第 19 卷　
dro lysis in 1 mo löL HC l at 60℃ fo r 8 m in. Squash p repara t ion s w ere m ade in aceto2
carm ine. Ch romo som e coun ts w ere m ade from 30 som atic m etaphase cells. T he ch romo2
som e classif ica t ion fo llow ed L evan et a l. [5 ] , the index of rela t ive length fo llow ed Guo et
a l. and the karyo type asymm etry index fo llow ed A rane [6 ].
F ig. 2　The somatic chromosomes and karyotype of C. g rand is
2　Results
T he karyo type of
C. g rand is is 2n =
2 sm + 10 st + 10 t.
T he ch romo som e mo r2
pho logy and karyo type
are show n in F ig. 2.
T he karyogram s are
show n in T ab le 1 and
the ideogram is show n
in F ig. 3. T he ra t io of
F ig. 3　 Idiogram of C. g rand is
the longest ch romo som e to the sho rtest one is
1171. T he index of rela t ive length is 2n = 1 L +
3 M 2+ 7 M 1. T he index of karyo type asymm etry
is 84133%. T he ch romo som e mo rpho logy of C.
g rand is is sim ilar to that of C. p a rnassif olia [6 ] ,
bo th show h igh degree of asymm etry. T he mo st
obviou s difference is that sa tellites ex ists in C.
p a rnassif olia w h ile no satellites are found in C.
g rand is.
Table 1　The karyogram s of C. g rand is
Ch romo2
som e
N o.
Relative length
L ong arm
(% )
Sho rt arm
(% )
Relative
to tal
length
(% )
IRL 3 A rm
ratio
C lassi2
fication
1 8. 78 3. 76 12. 54 1. 38 2. 33 sm
2 8. 97 2. 19 11. 16 1. 23 4. 09 st
3 9. 10 9. 75 10. 66 1. 17 5. 80 st
4 9. 22 1. 06 10. 28 1. 13 8. 05 t
5 7. 84 1. 25 9. 09 1. 00 6. 25 st
6 7. 08 1. 26 8. 34 0. 92 5. 65 st
7 7. 21 0. 94 8. 15 0. 90 7. 67 t
8 7. 21 0. 75 7. 96 0. 88 9. 58 t
9 5. 96 0. 81 6. 77 0. 74 7. 31 t
10 6. 58 1. 13 7. 71 0. 85 5. 83 st
11 6. 39 0. 95 7. 34 0. 81 6. 80 t
　　3 IRL. = Index of relative lengh t.3　D iscussionT he degree of karyo typeasymm etry in C. g rand is and C.p a rnassif olia is the h ighest a2mong the fam ily A lism ataceae.S ag itta ria , R ana lism a andE ch inod orus are genera lly con2sidered as the mo re advancedgroup s in the fam ily, bu t theyst ill have a pair of large m edian
ch romo som es in their som at ic
cells. Paleon to logica l studies have indica ted that Ca ld esia p lan ts appeared in the N ew
981　第 3 期　　　　　　　　　王 勇等: 珍稀水生植物——宽叶泽苔草的核型研究 (英)
W o rld as recen t ly as Early M iocene, 17 M a to 42 M a years la ter than the first reliab le
fo ssil reco rd of A lism ataceae p lan ts[7, 8 ]. Bearing in m ind that ch romo som e mo rpho logy
p lays an impo rtan t ro le in taxonom ical research (especia lly a t fam ily level[9 ] ) and that
fo ssil reco rds are overw helm ing evidence in discu ssing the evo lu t ionary rela t ion sh ip s of
p lan ts, w e con sider Ca ld esia to be p robab ly the mo st advanced group in the A lism at2
aceae.
Acknowledgmen t: 　W e w ould like to exp ress our thank s to M r. X iao Baizhong fo r h is help during
our field w o rk in 1999.
References:
[ 1 ]　W ang Q F, Chen J K. F lo ral o rganogenesis of Cald esia p arnassif olia (Bassi ex L ) Parl (A lism ataceae). A cta
P hy totax S in , 1997. 35 (4) : 289 292.
[ 2 ]　M ak ino. O bservations on the flo ra of Japan. B ot M ag T oky o. 1906. 20: 23 35.
[ 3 ]　L in Q , L iu K M. N o tes relating to flo ra of H unan: II. Caryophyllaceae, Fagaceae, Um belliferae, Rub iaceae, Com 2
po sitae, A lism ataceae. B u ll B ot R es, 1997. 17 (1) : 47 50.
[ 4 ]　L aiM J. A re2evaluation of a Cald esia p lan t in T aiw an. T a iw an ia, 1997, 22 (1) : 100 104.
[ 5 ]　L evan A , F redge K, Sandberg A A. N om enclatu re fo r cen trom eric po sit ion on ch romo som es. H ered itas, 1964,
52: 201 220.
[ 6 ]　W ang Q F, Chen J K, Guo Y H. Karyo typ ical and taxonom ical studies on A lism ataceae from Ch ina. P roc. Sec.
Sino2Jpn. Sympo sium P l Ch rom. P l Ch rom R es, 1992, 359 365.
[ 7 ]　Kristina K H , B ruce H T. T he flo ra of the early m iocene brandon lign ite, V ermont, U SA. Ð. Cald esia (A lism at2
aceae). A m er J B ot, 1997, 84 (2) : 239 252.
[ 8 ]　Charles P D. A review of the fo ssil reco rd of monoco tyledons. B ot. R ev , 1981, 47 (4) : 517 555.
[ 9 ]　Stebb ins G L. Ch romo som al evo lu tion in h igher p lan ts. L ondon: Edw ard A rno ld (Pub lishers) L td, 1971.
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