Table Of Content植物研究雑誌
J.Jpn.Bot.
82:29–33(2007)
Cytological Studies of the Genus Carex (Cyperaceae) in
the Osumi Islands (Kagoshima Prefecture) I. Chromosome Counts
of Five Species Collected from Yakushima Island
Okihito YANOa, Taro NANAMIb, Kumiko ITOb, Hiroshi IKEDAa,b and Takuji HOSHINOa,b
aDepartmentofMathematicalandEnvironmentalSystemScience,GraduateSchoolofInformatics,
OkayamaUniversityofScience,
1-1,Ridai-cho,Okayama-shi,Okayama,700-0005JAPAN;
E-mail:[email protected]
bDepartmentofBiosphere-GeosphereSystemScience,GraduateSchoolofInformatics,
OkayamaUniversityofScience,
1-1,Ridai-cho,Okayama-shi,Okayama,700-0005JAPAN
(ReceivedonJune12,2006)
FivespeciesofthegenusCarexcollectedfromtheYakushimaIslandweresubjected
to karyomorphological analysis. Chromosome numbers of C. atroviridis (2n(cid:1)70), C.
morrowii var. laxa (2n(cid:1)38) and C. odontostoma (2n(cid:1)30) were determined for the first
time. Two taxa endemic to the Yakushima Island, C. atroviridis and C. morrowii var.
laxa,hadthesamechromosomenumbersastheirallies,respectively.Carexwarburgiana
had a chromosome number of 2n(cid:1)28, which was new for this species. A chromosome
number of 2n(cid:1)22 for C. grallatoria var. heteroclita corroborates previous reports. A
dwarf type of C. odontostoma with a chromosome number of 2n(cid:1)30 was also found on
theYakushimaIsland.Therewerenokaryomorphologicaldifferencesbetweenthedwarf
and common types of C. odontostoma.
Key words: Carex, chromosome number, Cyperaceae, endemic, Yakushima Island.
The Japanese Carex are represented by Many vascular plants endemic to the island
over 200 species (Ohwi 1936, Akiyama have been reported (Masamune 1934,
1955, Koyama 1962, Katsuyama 2005). Yahara et al. 1987), including representa-
While the chromosome numbers of several tives from the genus Carex. Masamune
Japanese Carex species have been reported (1934) reported that eighteen taxa belonging
by Tanaka (1948), Hoshino (1981), Ohkawa to the genus Carex were to be found on the
and Yokota (1998) and Yano et al. (2006), Yakushima Island, six of which were
few cytological studies on the representa- regardedasendemictotheisland.Sometime
tives from the Osumi Islands have been later Yahara et al. (1987) recognized three
undertaken to date. Accurate karyomorpho- species, C. atroviridis, C. morrowii var. laxa
logical studies are important for understand- and C. yakushimensis, asendemic to the
ing the evolution and diversification of this island. In this paper the chromosome num-
genus on the islands. bers of five species of the genus Carex from
The Yakushima Island belongs to the Yakushima Island are reported and relation-
Osumi Island group and is located approxi- ships between the species and allies are
mately 60 km south from the mainland of briefly discussed.
Kagoshima Prefecture in Kyushu, Japan.
—29—
30 植物研究雑誌 第82巻 第1号 平成19年2月
Materials and Methods phase chromosomes were very small and
Five species of the genus Carex collected werelessthan1.0µminlength.Ohwi(1936)
from the Yakushima Island were used for reported that C. atroviridis is closely related
karyomorphological observations. The mate- to both C. dolichostachya and C. multiflora
rialsexaminedarelistedinTable1.Ofthese, var. multiflora. The chromosome number of
C.atroviridisandC.morrowiivar.laxahave C. multiflora var. multiflora was also
been reported to be endemic to the reported to be 2n(cid:1)70 by Hoshino (1981)
Yakushima Island (Yahara et al. 1987). and our results may suggest a close relation-
Somatic chromosomes were observed in the ship between C. atroviridis and C. multiflora
meristematic cells of root-tips or shoot- var. multiflora.
apices, which were pretreated in 0.002 M 8- Carex grallatoria var. heteroclita was
hydroxyquinoline solution for 1 h at 23°C foundtohaveachromosomenumberof2n(cid:1)
and 15 h at 4°C. These were then fixed in 22, confirming previous reports (Hoshino
acetic alcohol (1 : 3) for in excess of 16 h at 1981). The somatic metaphase chromosomes
–20°C or for 1.5 h at 23 °C, stained by ranged from 1.0 to 1.5 µm in length (Fig.
Feulgen’s nuclear reaction, macerated in a 1B).Thechromosomenumberforthetypical
mixture of 2 (cid:1)pectinase and 2 (cid:1)cellulase variety C. grallatoria var. grallatoria was
for1hat37°C,restainedin1(cid:1)aceto-orcein reported as being 2n(cid:1)18 by Tanaka (1948)
and squashed. Voucher specimens were de- or 2n(cid:1)17 and 18 by Hoshino (1981). These
posited at the Herbarium of Okayama two varieties could be distinguished princi-
University of Science (OKAY), Japan. pally by their sexual characteristics, i. e.,
monoecious C. grallatoria var. heteroclita,
Results and Discussion vs. dioecious C. grallatoria var. grallatoria.
The chromosome numbers determined in Our results suggested that the two varieties
this study are shown in Table 1. The num- could also be distinguished by cytological
bers are reported for the first time for Carex characteristics.
atroviridis, C. morrowii var. laxa and C. Carex morrowii var. laxa had a chromo-
odontostoma. some number of 2n(cid:1)38. Somatic metaphase
Carexatroviridishadachromosomenum- chromosomes ranged from 0.9 to 1.6 µm in
ber of 2n(cid:1)70 (Fig. 1A). The somatic meta- length (Fig. 1C). The chromosome number
Table 1. Species, localities and voucher specimens and chromosome numbers of five species of the genus Carex
collectedfromYakushimaIslandinKagoshimaPrefecture,Japan
Chromosome
Species Localityandvoucherspecimen
number(2n)
C.atroviridisOhwi
Kumage,Kamiyaku,Mt.MiyanouratoMt.Nagata,1500malt.;Katsuyama&al.19593(OKAY) 70
C.grallatoriaMaxim.var.heteroclita(Franch.)Kük.
Kumage,Yaku,Yodogawa-goyatoKo-hananoego,1680malt.;Ikeda&al.19440(OKAY) 22
C.morrowiiBoottvar.laxaOhwi
Kumage,Yaku,HanaageRiver,152malt.;Hoshino&al.19423(OKAY) 38
C.odontostomaKük.(Commontype)
Kumage,Yaku,HanaageRiver,156malt.;Hoshino&al.19424(OKAY) 30
C.odontostomaKük.(Dwarftype)
Kumage,Yaku,Ko-hananoegotoMt.Miyanoura,1680malt.;Ikeda&al.19441(OKAY) 30
C.warburgianaKük.
Kumage,Yaku,Senpirono-taki,225malt.;Hoshino&al.19426(OKAY) 28
February2007 JournalofJapaneseBotanyVol.82No.1 31
Fig.1. PhotomicrographsofsomaticmetaphasechromosomesoffivespeciesofthegenusCarexfrom
Yakushima Island. A. C. atroviridis (2n(cid:1)70). B. C. grallatoria var. heteroclita (2n(cid:1)22). C. C.
morrowii var. laxa (2n(cid:1)38). D. C. odontostoma (common type) (2n(cid:1)30). E. C. odontostoma
(dwarftype)(2n(cid:1)30).F. C.warburgiana (2n(cid:1)28).
32 植物研究雑誌 第82巻 第1号 平成19年2月
Table 2. Comparison of the size of culms, leaves and spikelets of two types of Carex odontostoma from the
YakushimaIsland
Dwarftype Commontype
Culmlength 3.5–5.0cm 20.0–45.0cm
Leafsize 1.5–2.5mm×3.0–12.0cm 2.5–3.5mm×10.0–50.0cm
Pistillatespikelength 0.5–1.0cm 1.0–3.0cm
Staminatespikelength 1.0–1.8cm 2.0–4.0cm
of the typical variety C. morrowii var. metaphase chromosomes ranged from 1.0
morrowii was also reported as 2n(cid:1)38 by µm to 2.3 µm in length. While C.
Tanaka (1948) and Hoshino (1981), and our warburgiana generally flowers in spring, all
results may support the treatment to recog- individuals from Yakushima Island were ob-
nize them as varieties of a species. served to flower in autumn (Katsuyama
Many dwarf plants have been reported on 2005). Katsuyama (2005) suggested that C.
the Yakushima Island (Sugimoto 1957), and warburgiana in Yakushima Island may be a
the dwarf type of C. odontostoma were dis- new taxon. Ohkawa and Yokota (1998)
covered on the Ko-hananoego to Mt. reported a chromosome number of 2n(cid:1)30
Miyanoura(1680malt.)inthisstudy.Dwarf for C. warburgiana in three individuals from
types are smaller than the common C. the Ryukyu Islands (Amamiohshima and
odontostoma in the size of the culms, leaves Okinawa Islands). However, C. warburgiana
and spikelets (Table 2). The common type of in the Ryukyu Islands has been revised as
C. odontostoma from the Hanaage river (156 being C. tenuior by Katsuyama (2005).
malt.)intheYakushimaIslandwasfoundto Carex warburgiana belongs to section
have a chromosome number of 2n(cid:1)30 (Fig. Ferrugineae and has been closely related to
1D). The somatic metaphase chromosomes C. makinoensis (Ohwi 1936, Akiyama 1955)
ranged from 1.0 µm to 2.0 µm in length. The and to C. tenuior (Katsuyama 2005). The
dwarf type of C. odontostoma also had a chromosome number of C. makinoensis has
chromosomenumberof2n(cid:1)30,andsomatic been reported to be 2n(cid:1)28 and 30 by
metaphase chromosomes ranged from 1.0 Hoshino (1981). Our results may suggest
µmto2.0µminlength(Fig.1E).Therewere close relationship among C. warburgiana, C.
no karyomorphological differences between makinoensis and C. tenuior.
the common and dwarf types of C.
odontostoma. Carex odontostoma belongs to The authors thank to Mr. Teruo
section Ferrugineae, and has been seen as Katsuyama and Ms. Tomomi Masaki for
closely related to C. chrysolepis and C. their great help on field trips and in collect-
glabrior (Akiyama 1955, Katsuyama 2005). ing plant materials. This study was partly
The chromosome number of C. chrysolepis supported by a Grant-in-Aid for Scientific
has been reported to be 2n(cid:1)28 (Hoshino Research (B) for the Japan Society for the
1981) and 2n(cid:1)30 (Tanaka 1948). Our Promotion of Sciences, no. 1440517 (to
results may suggest a close relationship Hirokazu Tsukaya, National Institute for
between C. odontostoma and C. chrysolepis. Basic Biology).
Carex warburgiana has a chromosome
number of 2n(cid:1)28, which is new number for References
this species (Fig. 1F). The somatic AkiyamaS.1955.CaricesoftheFarEasternRegionof
February2007 JournalofJapaneseBotanyVol.82No.1 33
Asia. 257 pp. Hokkaido Univ., Sapporo (in Ohwi J. 1936. Cyperaceae Japonicae. I. A synopsis of
Japanese). the Caricoideae of Japan, including the Kuriles,
Hoshino T. 1981. Karyomorphological and cyto- Saghalien, Korea and Formosa. Mem. Coll. Sci.
genetical studies on aneuploidy in Carex. J.Sci. KyotoImp.Univ.Ser.BBiol. 11:229–530.
Hiroshima Univ., Ser. B., Div. 2, Bot. 17: 155– Sugimoto J. 1957. On the pygmy plants of Yakusima
238. Island.Shokubutsu-Shumi 18:2–10(inJapanese).
KatsuyamaT.2005.CarexofJapan.376pp.Bun-ichi Tanaka N. 1948. The Problem of Aneuploidy.
SogoShuppan,Tokyo(inJapanese). Biological Contribution in Japan, 4. Hokuryukan,
Koyama T. 1962. Classification of the family Tokyo(inJapanese).
Cyperaceae 2. J. Fac. Sci. Univ. Tokyo Sect. III Yahara T., Ohba H., Murata J. and Iwatsuki K. 1987.
Bot.8:149–278. Taxonomic review of vascular plants endemic to
MasamuneG.1934.Floristicandgeobotanicalstudies YakushimaIsland,Japan.J.Fac.Sci.Univ.Tokyo
on the island of Yakushima. Mem. Fac. Sci. Agr. III,14:69–119.
TaihokuImp.Univ. 11:1–637. Yano O., Katsuyama T. and Hoshino T. 2006.
Ohkawa T. and Yokota M. 1998. Chromosome num- Cytological studies of seven taxa of Cyperaceae
bers and their variation patterns of Carex in the collected from the Bonin (Ogasawara) Islands. J.
RyukyuIslands.Cytologia 63:447–457. Jpn.Bot. 81:98–102.
矢野興一a, 名波太郎b, 伊藤久美子b, 池田 博a,b,
星野卓二a,b：鹿児島県大隅諸島産カヤツリグサ科
スゲ属植物の細胞学的研究I. 屋久島より採集し ミヤマイワスゲの矮小タイプ個体は2n(cid:1)30であり,
た5種の染色体数 核型分析を行った結果, 普通のタイプと差が認めら
大隅諸島屋久島より採集したカヤツリグサ科ス れなかった. バケイスゲ (C. warburgiana) では新
ゲ属植物5種について染色体数を報告した. 次の たに2n(cid:1)28を観察した. サナギスゲ (C. gralla-
3種については今回が初めての報告で,ヤクシマス toria var. heteroclite) は2n(cid:1)22であり, 従来の報
ゲ (Carex atroviridis) が2n(cid:1)70, ヤクシマカンス 告と一致していた.
ゲ (C. morrowii var. laxa) が2n(cid:1)38, ミヤマイワ (a岡山理科大学大学院総合情報研究科
スゲ (C. odontostoma) が2n(cid:1)30であった. このう 数理・環境システム専攻,
ち屋久島に固有のヤクシマスゲとヤクシマカンスゲ b岡山理科大学大学院総合情報研究科
は,それぞれ近縁群と同じ染色体数であった.また, 生物地球システム専攻)
