Karyotype of Keiskea japonica (Labiatae)

2011·0.73 MB·Danish

by  Norihito Miura

February 2011 Journal of Japanese Botany Vol. 86 No.1 49
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cm long. Flowers white, ca. 3 mm long; petals XXVIII. Bot. Mag. (Tokyo) 36: 117–132.
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　本研究は科学研究費補助金（基盤研究（C） specimens preserved in the Herbarium, Department
No. 21570105）による研究の一部である．有益 of Botany, the University Museum, the University of
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学総合研究博物館，京都大学総合博物館，首都大
田村　実，藤井伸二，西野貴子，山下　純，布施静香
学東京牧野標本館の関係者にお礼申し上げる． 2001．種子植物談話会からの報告・２・―野外植
物学観察会2001で観察した紀伊大島とその周辺域
の植物．日本植物分類学会ニュースレター no. 3:
11–14.
J. Jpn. Bot. 86: 49–51 (2011)
Norihito miuraa and Yoshikane iwatsubob,*: Karyotype of Keiskea japonica
(Labiatae)
aGraduate School of Science and Engineering, University of Toyama, 3190, Gofuku, Toyama, 930−8555 JAPAN
bDepartment of Biology, Faculty of Science, University of Toyama, 3190, Gofuku, Toyama, 930−8555 JAPAN
*Corresponding author: [email protected]
Summary: We examined the karyotype of Keiskea endemic species, K. japonica Miq., is distributed
japonica Miq. (Labiatae) collected from two localities in Honshu, Shikoku and Kyushu (Murata and
in Shizuoka Pref. They had 2n = 20 chromosomes, Yamazaki 1993). However, there has been no
which showed metaphase chromosomes ranging
information on the chromosome number of this
from 1.1 to 2.4 µm in length and 1.0 to 3.8 in arm
species. Here we will report the karyotype of
ratio. In the somatic chromosome complement, the
K. japonica and discuss the basic chromosome
longest pair was distinctly longes than the others, and
number of this genus.
the shortest pair had satellites on their short arms. The
We collected five K. japonica plants from the
present study determined that Keiskea japonica is a
diploid plant with a karyotype formulated as 2n = 20 following two localities in Shizuoka Prefecture:
= 8m+2tm+6sm+4st. three plants from Inokashira, Fujinomiya City,
and two plants from Mt. Ryuso-zan, Aoi-ku,
The genus Keiskea Miq. distributed in Shizuoka City. These plants were cultivated
China and Japan comprises approximately in the Experimental Garden at the Faculty of
six species (Li and Hedge 1994). In Japan an Science, University of Toyama. Karyotypes
50 植物研究雑誌　第86巻　第1号 2011年2月
Fig. 1. Photograph of somatic metaphase chromosomes of Keiskea japonica. A. Somatic metaphase.
B. Karyotype. Arrows indicate chromosome arms with satellites. Bars indicate 5 µm.
were determined from meristematic cells of root other nine pairs of chromosomes ranged from
tips subjected to the ordinal squash technique. 1.1 to 2.0 µm in length. Thus the chromosome
Root tips sprouted from the cultivated plant were length of the somatic complement of K. japonica
collected, pretreated in 2mM 8-hydroxyquinolin showed a bimodal variation (Fig. 1B, Table
at room temperature (ca. 25°C) for 1 hour, and 1). In the somatic chromosome complement,
kept at 5°C for 15 hours. Next, the root tips five pairs were metacentric, three pairs were
were fixed in a mixture of glacial acetic acid submetacentric and the other two pairs were
and ethyl alcohol (1:3) for 1 hour, soaked in 1N subtelocentric (Table 1). The karyotype was thus
t
hydrochloric acid at room temperature for 1 formulated as 2n = 20 = 8m+2 m+6sm+4st,
hour, macerated in 1N hydrochloric acid at 60°C and showed that this species is a diploid plant.
for 10 minutes, washed in tap water, and then We conclude that K. japonica has a basic
stained in a drop of 2% lacto-propionic orcein on chromosome number of x = 10.
a slide glass. Chromosome forms were described
according to the nomenclature proposed by This work was supported in part by a
Levan et al. (1964). Research Fellowship for Young Scientists from
All five plants observed had 2n = 20 the Japan Society for the Promotion of Science
chromosomes (Fig. 1A). Of the chromosomes (no. 20011439) to N. Miura.
at somatic metaphase, the pair with the longest
chromosomes was 2.4 µm in length, while the
Table 1. Measurements of somatic metaphase chromosomes of Keiskea japonica
Chromosome pair Length (μm) Arm Ratio Form
1 0.6+1.8 = 2.4 3.0 st
2 0.6+1.4 = 2.0 2.3 sm
3 0.4+1.5 = 1.9 3.8 st
4 0.8+1.0 = 1.8 1.3 m
5 0.5+1.2 = 1.7 2.4 sm
6 0.5+1.1 = 1.6 2.2 sm
7 0.7+0.8 = 1.5 1.1 m
8 0.6+0.8 = 1.4 1.3 m
9 0.6+0.6 = 1.2 1.0 M
10 t–0.5+0.6 = 1.1 1.2 m
t: small satellite.
February 2011 Journal of Japanese Botany Vol. 86 No.1 51
References and Yamazaki 1993)．シモバシラ属については，染色
Levan A., Fredga K. and Sandberg A. A. 1964. Nomen- 体の報告はこれまで全く行われていないことから，今回，
clature for centromeric position on chromosomes.
シモバシラについて，染色体数および核型を明らかにし
Hereditas (Lund) 52: 201–220.
た． 静岡県の2カ所で採集したシモバシラ5個体につい
Li X.-W. and Hedge I. C. 1994. Keiskea Miquel. In: Wu Z.-
Y. and Raven P. H. (eds.), Flora of China 17: 257–258. て観察した結果，すべて2n = 20であった (Fig. 1A)．体
Science Press, Beijing and Missouri Botanical Garden 細胞中期の染色体長は1.1–2.4 µmで，腕比は1.0–3.8
Press, St. Louis. であった (Fig. 1B, Table 1)．また，核型式は2n = 20 =
Murata G. and Yamazaki T. 1993. Keiskea Miq. In: 8m+2tm+6sm+4stで表され，2本が特に長く，他の18
Iwatsuki K., Yamazaki T., Boufford D. E. and Ohba H.
本の染色体の長さは次第に短くなっていた．最も短い染色
(eds.), Flora of Japan IIIa: 301. Kodansha Ltd., Tokyo.
体対には付随体があり，基本数x = 10の2倍体であると
シモバシラ（シソ科）の核型（三浦憲人a，岩坪美兼b） 考えられた．
シモバシラ Keiskea japonica Miq.（シソ科）は日本固 （a富山大学大学院理工学教育部，
有の植物で，本州，四国，九州に分布している (Murata b富山大学理学部生物学科）