全 文 ：江西发现绵枣儿多倍体复合体多细胞型混合居群
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丁开宇 , 孙静贤 , 王 伟?? , 王兵益??? , 王跃华
( 云南大学生命科学学院 , 云南 昆明 650091 )
摘要 : 对来自江西省新干县三湖镇绵枣儿 ( Scilla scilloides) 多倍体复合体两个居群 263 个植
株进行了细胞学调查 , 发现 4 个整倍体细胞型 , 即 BB、BBB、BBBB 和 ABBB。其中 BBBB 和
ABBB 为大陆上首次记录。至此在东亚大陆上已经发现该多倍体复合体 12 个整倍体细胞型中
的 9 个。这表明东亚大陆也是该复合体细胞型分化的重要地区之一。此地出现 ABBB 和 BBB ,
而未出现 ABB以及非整倍体可能是说明自第四纪以来 BB 细胞型在大陆和朝鲜半岛的分布区
正在收缩 ; 大陆上 AABB 已经接近消失 ; 而大陆、朝鲜半岛和济州岛 (韩国) 的 BB 和 AABB
混合居群只是残遗。大陆与日本列岛居群细胞型组成的相似性可能暗示着它们的某种历史关
系 , 但是并不能支持日本分布的绵枣儿是从中国引入的“史前归化”植物。
关键词 : 绵枣儿 ; 多倍体 ; 分布
中图分类号 : Q 943 文献标识码 : A 文章编号 : 0253 - 2700 (2005) 05 - 0501 - 08
Multicytotypic Populations of Scilla scilloides Polyploid
Complex Found in Jiangxi , China
DING Kai-Yu, SUN Jing-Xian, WANG Wei ** , WANG Bing-Yi * ** , WANG Yue-Hua
( School of Life Science, Yunnan University, Kunming 650091 , China)
Abstract: Two populations ( located at Sanhu town, Xingan co . , Jiangxi province) of Scilla scilloides
polyploid complex were surveyed cytologically, and four cytotypes, BB , BBB , BBBB, and ABBB were
observed among two hundredand sixty three individuals . BBBB and ABBB were newrecords in East Asian
continent . Until now, nine of the 12 euploid cytotypes of this polyploid complex have been found in the
East Asian continent, which suggests the continent is one of the important locations where the cytotypic
differentiation of the complex takes place . The occurrence of ABBB and BBB , but not ABB and aneu-
ploids maybe demonstrates the distribution rangeof BB havecontracted on thecontinent and Korean penin-
sula, AABB populations of plants with subglobose bulb have degenerated on the continent since Tertiary,
and the mixed populations of BB and AABB are the relicts of populations on the continent, Korean penin-
sula and Cheju island . Thecytotypecomponent similarity in these populations to that in populations on the
云 南 植 物 研 究 2005 , 27 (5) : 501～508
Acta Botanica Yunnanica

?
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??? ?现工作单位为中国林业科学院资源昆虫研究所 ( 昆明 )
Received data: 2005 - 01 - 24 , Accepted data: 2005 - 05 - 11
作者简介 : 丁开宇 (1963 - ) 男 , 博士 , 主要从事系统与进化植物学研究。 E - mail : kyding@ynu. edu. cn ?
现为植物研究所博士研究生 ?
Foundation item: The National Natural Science Foundation of China ( 30270095 ) , Yunnan Natural Science Foundation
(2000C0009M )
Japanese archipelago may showsome historical relations between them, but this fact is not able to manifest
the hypothesis that this species onthe Japanese islands is oneof“prehistoric naturalized”plants introduced
fromChina .
Key words: Scilla scilloides; Polyploidy; Distribution
Most researchers consider there is only one squill species in East Asia, but several names are
given to it . Themost commonone is Scilla scilloides (Lindl .) Druce ( Wang and Tang, 1980) ; be-
sides, some authors named it as S. sinensis (Lour .) Merr ., S. chinensisBenth ., or Barnaradia ja-
ponica (Thunberg) Schultes& J . H . Schultes (Chen and Tamura, 2004) . In this paper, however,
attention is not paid to its nomenclature, theopinionof themost authors is followed temporarily and its
cytotype components anddistribution arediscussed . Up to date, 12 euploid andvarious aneuploid cy-
totypes have been found, which contains either or both of two distinctly different genomes, A (x= 8)
and B (x = 9) . Of these cytotypes, AA , BB andAABB are thebasicones (Morinaga, 1932; Sato,
1942; Araki , 1985; Yu and Araki , 1991; Bang and Choi , 1993; Ding et al ., 1998 ) . Japa-
nese archipelago is characteristic of having mixed populations of BB , AABB and some unbalanced
polyploids, such as ABB , BBB, ABBB, and various aneuploids derived from the autopolyploidi-
zation of BB and the hybridization of BB and AABB (Haga and Noda, 1976; Ihara, 1977; Araki ,
1972 , 1975; Araki et al ., 1976) , while themajority of populations in China aremonotypic onesof
AA, BB or AABB (Yu and Araki , 1991; Yu et al ., 1992; Ding et al ., 1998 ) . A mixed popu-
lation of BB, BBB and AABB, however, was found at the Sanhu Town, Xingan co ., J iangxi prov-
ince (Ding et al ., 1998) . So it is suggested that someother cytotypes, similar to ones found in Ja-
pan, can be detected in the region where this population is located . In order to verify this presump-
tion, two populations were sampled for the cytological investigation again in April 2002 and the results
are reported as followed .
Material and Methods
Sanhu Town is located at the west sandbank of Gan River in the north part of Jiangxi province . Two populations
were sampled nearby it . Thehabitat of PopulationI isa rape fieldand itsmargins outsidethewest bank of the river about
300 meters south to thetown, while Population II occupies a habitat insidethe east bank directlyopposite to the former .
In thesetwo populations, bulbs were collected at random, and the bulbs sampled were morethan onemeter in distance
to avoid collectingmany bulbs of the same clone becausevegetative reproduction is very effective in the populations (our
observation) . In addition, all bulbswith diameter morethan 0.5 cmwere collected froman approximately 0 .16 m2 sec-
tion in Population I .
Thesomatic cellsof root-tipswere cytologically analyzed . Thebulbswere cultured inwater and whenthe roots grew
upto1 - 2 cm, the root-tipswere incised, pretreatedwith saturated p-Dichlorobenzenesolutionfor about 4 hours at room
temperature, fixed in 3∶1 ethanol-acetic acid for at least 24 hours at 4℃ and transferred to absolute ethanol for further
storage at - 18℃ . The fixed root-tips were macerated in 0 .1 mol?L HCl at 60℃ for 4 - 5 minutes, then squashed with
modified Carbol fuschin (Li and Zhang, 1991 ) . One root-tip was analyzed for each individual . Identification of ge-
nomes followed Araki (1971 ) . The A genome is composed of eight chromosomes, of them, the largest metacentric
205 云 南 植 物 研 究 27 卷
chromosome ( a1 ) is its marker . The B genome consists of nine chromosomes for which a marker is a subterminal chro-
mosome with a secondary construction at the proximal end of the short arm (b1 ) .
Results
Two hundred and sixty three individuals of three samples, one randomsample in each of the two
populations and a 0 .16 cm2 section sample in Population I , were cytologically analyzed, and the re-
sult is shown in Figure 1 and Table 1 . Four cytotypes, i . e . BB , BBB, BBBB, and ABBB were
detected, and, being calculated on all the three samples, the frequency of BB individuals is the
highest ( 46 .0% ) , next the ABBB ( 41 .4% ) , then the BBB ( 11 .4% ) , and the lowest BBBB
(1 . 1% ) . It is worth noting thepresenceof BBB, ABBB andBBBB is not accompaniedby theunbal-
anced triploid ABB and various aneuploids in the two populations . On theother hand, these euploids
are relatively common components in Japanesepopulations, and the aneuploids make up a little prop-
ortion of many populations on the Japanese archipelago, Korean peninsula and Cheju Island ( Araki ,
1972 , 1975 , 1985; Araki et al ., 1976; Haga and Noda, 1976) .
Table 1 Genome Constitutions of Scilla scilloides in two populations nearby Sanhu
Population 2 ?n Genome constitute* Number of individuals Percentage in populations?samples
I 18 ?BB 33 60 {. 0
27 ?BBB 1 1 h. 8
35 ?ABBB 21 38 {. 2
II 18 ?BB 24 45 {. 3
27 ?BBB 29 54 {. 7
The sectional sample 18 ?BB 64 41 {. 3
in Population I 35 ?ABBB 88 56 {. 8
36 ?BBBB 3 1 h. 9
* The types and number of B chromosomes are not taken into account becauseof their variation through vegetative propagation as well as
sexual reproduction
Discussion
East Asian continent being the major stage for the evolutionary drama of this complex
Up to date, mostof thecytotypes in this polyploid complex havebeen foundon the continent, so
further investigation in continental populations must be primitively essential to understand itsorigin and
evolution . Beginning in 1930 s, the cytological investigations of this complex have been conducted by
many authors in a large number of populations almost all over its distribution range, except for the
north part of the Korean peninsula, and as much as 12 euploids, i . e . AA , AB, BB , AAA ,
ABB, BBB, AAAA , AABB , ABBB, BBBB, AABBB , AAABBB and various aneuploids have
been found . In the meanwhile, its cytogeographical pattern has gradually changed into being clear .
First, The two fundamental diploids, AA and BB , and the key allopolyploid AABB are the major
components in continental populations (Yu and Araki , 1991; Ding et al ., 1998) , but AA does not
exist in the Japanese archipelago ( Ihara, 1977) and BB does not in the Korean peninsula ( Araki ,
1985; Bang and Choi , 1991) . Second, three of them, that is, AB, AAA , and AAAA are found
3055 期 丁开宇等 : 江西发现绵枣儿多倍体复合体多细胞型混合居群
Fig . 1 Light micrographs of mitotic metaphase (×1350) and Karyodiagram . 1 and 5 , cytotype ABBB ( 2n= 35 + B) ; 2 and 7 ,
cytotype BBBB ( 2n= 36 + 4Bs) ; 3 and 6 , cytotype BBB (2n= 27 ) ; 4 and 8 , cytotype BB (2n= 18 ) . a1 is the marker
chromosomeof A genome and b1 is the marker chromosome of B genome . Arrows indicate B chromosomes ( Bs) .
only in continental populations (Yu and Araki , 1991; Ding et al ., 1998 ) . Third, some unbal-
anced polyploids, such as BBB , ABBB , and BBBB, not only occur in the Japanese and Cheju is-
land, but also in the continent . Ingeneral , of the 12 cytotypes found until now, 9 cytotypes exist in
405 云 南 植 物 研 究 27 卷
continental populations, except for ABB , AABBB , AAABBB . In other words, the continent must
be the major stage for the evolutionary dramaof this complex . However, little is known about most of
its evolutionary mechanismand cause, such as theoriginof this polyploid complex, thedifferentiation
betweenAA and BB , the formation of the current cytogeogrphical pattern and the ecological factors
actingon them . Thus, deep investigations in continental populations, using synthetically molecular
and other methods, are exactly essential to elucidate the evolutionary course of the complex .
BB cytotype’s retreat from north to south and extinct of type Ⅱ of AABB cytotype
In the Scilla scilloides polyploid complex as is the case in someother polyploid complex, it is no
doubt the first step to the structural complication of populations is the encounter and hybridization of
BB and AABB (one ancestral diploid and its allopolyploid) in the same populations and theproduction
of ABB from it . The key step to it, however, must be the selfingof and?or crossing between ABB,
and crossing of ABB with BB and?or AABB , which is an important conclusion coming fromthe open
pollination experiment of ABB , BB, BBB, ABBB and AABB plants conducted by Araki (1972 ) in
which ABB has prominently higher seed settings (6 . 9% ) than the other unbalanced polyploids, BBB
(0 . 0% ) and ABBB (0 . 8% ) , and the progenies of ABB plants as mothers havevarious chromosome
complements includingBB, ABB , AABB, ABBB and many chromosome-absence and -addition types
at different ploidy level . So it can be claimed that the allotriploid ABB must play a crucial role in the
structural complicationof populations . Ramsey and Schemscke (1998) also recognized the importance
of triploids in polyploid formation, and called it as“ triploid bridgepathway”to polyploidization . Now
it is reasonable to assumed BBB, BBBB , and ABBB be the progenies of ABB in these two popula-
tions . WhywereBBB , BBBB , and ABBB but not ABB and aneuploids observed in these two popula-
tions ? It is probably not considered as a sampledeviation, because the averagenumber of sampled in-
dividuals per population is enough to detect this cytotype in percentagesimilar to that in Nakabarupop-
ulation (Araki , 1972) , and ABB was also not found in asurvey of 36 individuals sampled in Popula-
tion I (Ding et al ., 1998) . Considering the complex’s cytogeography as a whole, one of the most
possible explanations is that the distribution range of BB in the continent and Korean peninsula and
AABB ( it must be limited as that discussed below) in the continent are having contracted from the
north to thesouth now, and themulticytotypic populations in J iangxi and Cheju islandof Korea arethe
relicts of its distribution before .
In the first, according the resultsof Araki (1985) , Bang and Choi (1991 , 1992) , andYu and
Araki (1991 ) , it can beseen that unbalanced euploid and aneuploid individuals alwaysoccur in pop-
ulations with AABB as the fundamental element, whileBB arenot found in any populations in theKo-
rean peninsula . The frequency and type number of unbalanced euploid and aneuploid individuals in
populations decline with the reduction of the latitude, for example, the percentage and type number
are 1 .25 and 1 in Ji’an (41°N) , 3. 37 and 3 in Chuncheon (38°N) , 5 . 97 and 4 in Bugi (36°N)
in the Korean peninsula . In addition, as much as 4 unbalanced euploids, i . e . ABB , ABBB,
AABBB , and AAABBB , have been found up to date and the percentageof these cytotypes is as high
as 16 .55 in Cheju (34°N) , asmall island just south to the peninsula . Inour observation in this two
5055 期 丁开宇等 : 江西发现绵枣儿多倍体复合体多细胞型混合居群
populations located at approximately altitude 28°N, there are 3 unbalanced polyploids are found and
more than half of the sampled plants are these cytotypes . The most rational inference from this phe-
nomenonmay be that BB isgradually retreatingfromthe north to thesouth in theKorean peninsulaand
Cheju island, while ABB disappeared once upon the retreat of BB because of its nonsexual reproduc-
tion and possibleephemerality in a changed climate . Furthermore, there are not newones so produced
from thehybridizationof ABB andBB?AABB as to fill up the decreaseof unbalanced euploids and ane-
uploids due to also their nonsexual reproduction and ephemerality ( it is reasonable to believe their life
is shorter than balanced euploids) . Therefore, the more norther the population is, the earlier BB’s
retreat occurs and the less unbalanced euploids and aneuploids in populations are . In other words,
the current distribution range of BB is possibly much smaller than it did in the past . Themajor factor
actingon it may be, by and large, the decrease of the temperature in these regions since Tertiary
(Chen, 1989) . However, BB, commonly accompanied with various unbalanced euploids and aneu-
ploids, occurs all over the Japanese archipelago, and a northernmost BB population was revealed in
the south part of Hokkaido island, which latitude (42 - 43°N) is much higher than that of the north
boundary of BB on the continent (32°N) . It may bedue to relatively ahigher temperature and mois-
ture in winter in Japanese archipelagothan thaton the continent becauseof its situation in thesea ( due
to the buffering effect of sea) .
In the second, thedegenerationof AABB populations probably takes place in the continent at the
same timewhen thedistribution rangeof BB contracts . It must bepointedout in advancethat, on the
continent, AABB can be classified into two types according their morphology and distribution . Type
Ⅰ has subglobosebulbs with indistinct naked discs, spreads over East and Central China to thenorth
of Changjiang river, and consists large and extremely flourishing populations . Type Ⅱ has fusiform
bulbs with columelliform naked discs at their bottom, lies scattered in regions closely on the south of
Changjiang river, and is composed of only two purepopulations with littleplants (Ding et al ., 1998)
and the mixed populations (see the result) . Here and nowonly the typeⅡ is meant by AABB .
In fact, this AABB cytotype has been found in only three populations and may occupy a very
small region with its diameter not more than 400 kilometers, approximately situated at the center of the
current distribution rangeof BB . Two of the three are pureAABB populations, being located at Baiy-
ang and Pengchengvillages about300 kilometerson thenorthof thesetwo populations, andonly7 and
3 plants could be collected respectively in them (Ding et al ., 1998) . Another one is this population
Ⅱin which plants with AABB genome were detected to make up only a little proportion ( 2 . 6% ) and
no ABB plants were found (Ding et al ., 1998) . All the above fact may suggests this AABB be the
remnants and the hybridization between it and BB have not occurred now .
However, it can be seen that the north border of AABB on the Korean peninsula and Japanese
archipelago is much northerner than that on the continent ( although, unfortunately, there is not any
information about the cytogeographyof this complex in thenorthpartof the Koreanpeninsula, consid-
ering the results of Araki (1985) , Yu andAraki (1991) and Ding et al . (1998) , it is reasonableto
presume AABB be a common cytotype in it) . A problem, hence, is brought about, that is, why do
605 云 南 植 物 研 究 27 卷
not AABB distribution rangeon thepeninsula and archipelago degenerateor contract in the samemanner
as mentioned above? A solution for it may be that temperature and moisture difference in these regions
fromthat in the continent . Another possible explanation is that between the AABB populations in the
two regions there is different adaptation resulted fromdifferent origins . This needs to verify further .
The relationship between the continental and Japanese populations of S. scilliodes
Although, perhaps, the rangeof thesemulticytotypic populations is relatively narrow in the con-
tinent, it maybe suggests some historical relation between the continental and Japanese archipelago
populations . Now, it can be considered there has been ahigh samplingdensity for the cytological in-
vestigation of this complex in the continent to date, so it can be believed that populations of this sort
should not exceed the range that includes the parts of Jiangsu and Anhui provinces south to the
Changjiang river and the north partsof Jiangxi and Zhejiangprovinces . In addition, thesemixed pop-
ulations possibly emerge in the boundary region between Hunan and Hubei provinces .
In respect to geography, thedistribution region of themulticytotypic populations in the continent
is just opposite to the south end of theJapanese archipelago, and their cytotypic components aremuch
similar to that of the latter ( the common cytotypes of them are BB , BBB , BBBB, ABBB, and
AABB) . Otherwise, it is very interesting that Cheju isl ., south to the Korean peninsula, is exactly
the step-stone between the two regions, on which the cytotype components are also analogous to that in
the two regions . In addition, it was proved that there is afloral homology between theJapanese archi-
pelago and East China ( Cheng, 1984) . So it is not impossible to interpret its distribution over the
Japanese archipelago as the result of natural history . On the contrary, after comparing the habitats of
this complex in China with that in Japan and finding that, in China, it“exists in wild habitats or
mountain regions as a relict or remnant of themuch older Tertiary flora (but, according toourobserva-
tion, it not only occupies wild habitats, but also some places affected deeply by human) , while in
Japan, it is found always in places closely associated with man’s activities, e.g ., agricultural
fields, roadsides, river banks, graveyards, etc .”, Maekawa ( 1944) suggested this species be not
native to Japan, but oneof the‘prehistoric-naturalized’plants introduced fromtheChinesemainland .
Araki ( 1985 ) and Ihara ( 1977) agreed with him and provided additional evidences for it, that is,
(1) some individuals, producingvegetatively due to unbalanced genomes, and dispersing for a long
distance, have the samegenomes in respect to normal genomes and B-chromosomes; (2 ) it is well
known as a food plant, being eaten in leanyears in Korea and Japan ( in fact, as afoodplant, it was
recorded as early as 1406 in China, see Zu Di ) . However, all of the mentioned above are indirect
evidences for this introduction presumption . If we want to clarify this problem, the comparison of its
populational genetic diversity and molecular phylogeny in Chinawith that in Korea and Japanmay give
a clue to it .
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