Table Of Content植物研究雑誌
J. Jpn. Bot.
Originals 73: 119-124 (1998)
Aneuploidy in Thelypteris laxa (Franch. & Sav.) Ching (Thelypteridaceae)
Na rumi NAKATO
Kokubunji High School，3- 2-5 Shin-machi，K okubu吋i-shi，Tokyo，1 85-0004 JAPAN
(Recei ved on No vember 17，1 997)
Chromosome number of Thelypteris laxa was determined，a nd two cytotypes，
2n=136 and 2n=134 were found. The former cytotype is regarded as tetraploid based on
x=34，an d the latter as aneuploid (hypotetraploid) of the former. In Jap an，th e hypotetraploid
seems to have aw ider distribution range than the eutetraploid.
Thelypteris laxa is distributed in Japan， sporangium was counted to ascertain whether
Korea (Cheju Is1.)， southern China and Tai- reproduction was sexual or apogamous.
wan. In Jap an it is commoni n warmt emperate Voucher specimens are deposited in TI (the
regions，o ccurring mainly in lightly shaded Botanical Gardens，Un iversity of Tokyo).
places in lowlands (Iwatsuki 1995). Preceding
chromosomal works have shown that this spe- Results and Discussion
cies has two basic chromosome numbers，x= 34 Chromosome number Chromosome num-
and 36; the former was suggested from mitosis bers were determined in 24 plants from 19
in root tip cells as 2n=1 36，a nd the latter from localities in Jap an (Table 1). Oft hese，3 p lants
meiosis in spore mother cells as n=36，3 61V or from 210calities were found to be 2n= 136，an d
72 (see Table 1). As to Japanese plants，Ku rita the remaining 21 plants from 17 localities
(1963) reported n=72 (x=36) from Kikugawa， were 2n=134 (Figs. 1& 2). The plants of
Shizuoka Pref.，w hile Nakato (1996) counted 2n=136 and those of 2n=134 were indistin-
2n= 136 (x=34) from Tsukubasan，Ib araki Pref. guishable morphologically.
In this paper，1 i ntend to report the results of a The basic chromosome numbers available
further chromosomal survey on plants from 19 so far in the genus Thelypteris sensu Iwatsuki
localities in Jap ani，nc luding an ewa neuploidal (1995) are diverse and are reported to be x=27，
cytotype which widely occurs. 30，3 1，3 2，3 4，3 5 and 36 (Takamiya 1996).
The 2n= 136 cytotype of T. laxa could safely be
Materials and Methods regarded as tetraploid based on x34，agreeing
二
Localities of materials are listed in Table 1. with the observations of Nakato (1996)，a nd
Plants were collected from native habitats，an d the 2n= 134 cytotype，ne wly found in this study，
cultivated in pots. For the observation of so- as aneuploid (hypotetraploid) of the former.
matic chromosomes，r oot tips were put in Chromosome numbers based on x=36，w hich
0.002 M 8-hydroxyquinoline for 4h ours，a nd was reported by Kurita (1963)，Ts ai and Shieh
fixed in 45% acetic acid for 10 minutes. The (1983) and Weng (1985)，w ere not encoun-
fixed roots were macerated with lNH Cl for 1 tered during the course of this study.
minute at 60oC，a nd squashed in 29もaceto- Occurrences of aneuploids in ace rtain spe-
orcein solution. The number of spores per cies have been often confirmed in various
-119-
120 植物研究雑誌第73巻第3号 平成10年6月
Table 1. Chromosome numbers of Thelypteris laxa (Franch. &S av.) Ching
Chromosome number /Pl oidy and basic chromosome number presumed
Locality /Re ference or voucher specimen (Nakato's No.)
Previous study
n=72，te traploid of x=36
Kikugawa，S hizuoka Pref. (Kurita 1963)
n=36IV，te traploid of x=36
Lienhuachih，Na ntou，Ta iwan (Tsai and Shieh 1983，19 85)
n=36，di ploid of x=36*
Hangzhou，Zh ejiang，C hina** (Weng 1985)
2n= 136，te traploid of x=34
Tsukubasan，Ib araki Pref. (Nakato 1996)
Present study
2n=136，te traploid of x=34
Sayama，Hi gashiyamatoshi，Tokyo Pref.，no . 2081 **
・
Umegaya-toge，Om e-shi，T okyo Pre ，.fnos. 2142**，21 43
2n= 134，hy potetraploid of x=34
Hagurosan，H aguromachi，Yamagata Pref.，no . 2131 **
田
Mizuho-machi，Ni shitama-gun，T okyo Pref.，no . 2097
Hinode-machi，Ni shitama-gun，T okyo Pref.，no . 1976
Hinohara-mura，Ni shitamルgun，Tokyo Pre ，.fnos. 1978，1 979**
Takao-san，Ha chioji-shi，T okyo Pref.，no s. 2068，20 69
Hatsukari-machi，Ot suki-shi，Y amanashi Pre ，.fno. 2216
Tatsuruhama-machi，Ka shima-gun，Is hikawa Pre ，.fno. 1932**
Shika-machi，Ha kui-gun，Is hikawa Pref.，no . 2226
Yugashima，Am agiyugashima-machi，Sh izuoka Pre ，.fnos. 2035*穴2036
Funabara，Am agiyugashima-machi，Sh izuoka Pre ，.fnos. 2062料，2063
Yadokoro，Ow ase-shi，M ie Pref.，no . 2125
Ouga，Sh ingu-shi，W akayama Pref.，no . 2105
Hikimi-cho，Mi no-gun，Sh imane Pre ，.fno. 2149料
Mochidagaura，Ha kata-ku，Fu kuoka-shi，Fu kuoka Pref.，no . 2113
Ikeda，Sa wara-ku，Fu kuoka-shi，Fu kuoka Pre ，.fno. 2127
Kumano，Bu ngotakada-shi，Oi ta Pref.，no . 2218
Fukata，Us uki-shi，Oi ta Pref.，no . 2222
* Octaploid (x=9) in the original paper. But n=36 should be assigned to diploid，be cause
species with n=9 or 18 have not been reported in this genus.
Specimensexamined for the number of spores per sporangium. All these have 64 good
料
spores m as porangmm.
families and genera in Japanese ferns: Isoetes stricted areas. Ont he contrary，in T. laxa，th e
japonica A.Br. and I. sinensis T.C. Palmer in hypotetraploids (2n= 134) seem to have aw ider
Isoetaceae (Takamiya et al. 1994)，Le pisorus distribution range than the eutetraploid
thunbergianus (Kaulf.) Ching in the (2n=136). The hypotetraploids may have ad-
Polypodiaceae (Nakato et a .l1983)，P teris vantageous attributes that caused these exten-
cretica L. in Pteridaceae (Nakato 1989)，et c. In sive distribution beyond the eutetraploids.
these species，a neuploids have been found Comparison 01 chromosome length between
rarely in euploid populations and/or in re- the two cytoηpes Although strict karyo-
June 1998 Journal of Japanese Botany Vo .173 No. 3 121
Figs. 1，2. Somatic chromosomes of Thelypteris laxa. 1. 2n=136，e utetraploid，no . 2142. 2. 2n=134，
hypotetraploid，no . 1978. Scale bar =5 μm.
logical analysis was difficult from nuclear mosome number in the hypotetraploid might
plates obtained in this study，th e sizes of chro- not arise from simple loss but from fusion of
mosomes could be measured and comped chromosomes.
訂
between those of the eutetraploid and the Reproductive system The spore numbers per
hypotetraploid. Figures 3a nd 4s how somatic sporangium could be counted in 2p lants of the
chromosome complements arranged by tetraploid and 6p lants of the hypotetraploid.
length，ea ch corresponding to those of Figs. 1 In all of these specimens，64 good spores were
and 2，re spectively. counted in each sporangium，i ndicating that
In the eutetraploid of no. 2142 (Fig. 3)，th e they are sexual in reproduction (Figs. 5& 6).
variation in chromosome length was gradual; This finding is in accordance with Momose
the chromosomes range in length from 1.9μm (1967) from the studies of prothallia.
to 0.9μm with the mean of 1.3μm; and the Cytotaxonomy 01 T. laxa and related species
longest chromosome was about 2.1 times as Iwatsuki (1995) classified the genus Thelypteris
long as the shortest. On the contrary，in the (37 spp.) of Japan into eight subgenera and
hypotetraploid of no. 1978 (Fig. 4)，t he first eight sections and placed T. laxa in subgenus
two chromosomes were much longer than the Thelypteris，se ction Metathelypteris，to gether
others，be ing 2.4μmi n length; the remaining with T. gracilescens (Blume) Ching，T .
chromosomes showed ag radual decrease in uraiensis (Rosenst.) Ching and T. hαttorii (H.
length from 1.8μmtoO.9μm; the mean length Ito) Tagawa. This section is referable to the
of all chromosomes was 1.2μm; and the length genus Metathelypteris recognized by Ching
of the longest chromosomes was about 2.4 (1963). The diagnostic characters of this group
times that of the shortest. The two larger chro- are: free veins，in dusiate sori，ab sence of aero-
mosomes were also observed in the comple- phore，ve inlets that do not reach the margin of
ments of other hypotetraploids. These results segments，a nd bipinnatifid to tripinnatifid
suggest the possibility that reduction of chro- fronds. Other Asian species allied to T. laxa
122 植物研究雑誌第73巻第3号 平成10年6月
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Figs. 3，4. Somatic chromosome complement arranged by length. 3. 2n=136 chromosomes from Fig. 1，n o.
2142.4. 2n==134 chromosomes from Fig. 2，no . 1978. Scale bar =5 μm.
Figs. 5，6 . Sixty-four spores in one sporangium. 5. Eutetraploid，no . 2142. 6. Hypotetraploid，no . 2131.
Scale bar =1 00μm.
June 1998 Journal of Japanese Botany Vol. 73 No. 3 123
are T. adscendens Ching，T. decipience Ching， Phytotax. Sin. 8: 289-335.
T. flaccida Ching and T. singalanensis Ching Hirabayashi H. 1969. Chromosome numbers in several
species of Aspidiaceae. 1. Jpn. Bot. 44: 113-119.
(Ching 196 ，3，Iwatsuki 1965).
Iwatsuki K. 1965. Taxonomy ofthe Thelypteroid ferns，
Among these species，t he following four
with special reference to the species of Japan and
species have been examined cytologically: T. a司jacentregions. IV. Enumeration of the species of
flaccidα(n=35 and n=70，M anton and Sledge Japan and adjacentregions. Mem. Col .1Univ. Kyoto，
B，31 : 125-197.
1954)，T. singalαnensis (n=70，Ma nton 1954)，
一一一一一 1995.Thelypteridaceae. In: Iwatsuki K.，
T. uraiensis (n=62，Hi rabayashi 1969; n=36IV，
Yamazaki T.，Bu ffordD.E. andOhbaH. (eds.)，Flora
Tsai & Shieh，1 983) and工laxa(see Table 1). of Japan，V o .11，pp . 174-194. Kodansya，To kyo.
From these data，it is assumed that the section Kurita S. 1963. Cytotaxonomical studies on some
Methathelypteris sensu 1wa tsuki (1995) (or leptosporangiate ferns. 1. Coll. Arts Sci. Chiba Univ.
4: 43-52.
the genus Metathelypteris sensu Ching，19 63)
Manton I. 1954. Cytological notes on one hundred spe-
is characterized by polybasic chromosome
cies of Malayan ferns. In: Holttum R. E.，A R evised
numbers such as x=31，3 4，3 5 and 36. These Flora of Malaya，V o .1H，pp . 623-627. Gov. Print.
clearly show that aneuploidy as well as poly- Office，Si ngapore.
一一一一-and Sledge，W . A. 1954. Observations on the
ploidy has played an important role in the
cytology and taxonomy of the Pteridophyte flora of
evolution of this group.
Ceylon. Philos. Trans. Roy. Soc. London，B ，2 38:
As statedearlier，T. laxais distributed widely 127-185.
in warm temperate areas ofE. Asia. However， Momose S. 1967. Prothallia of the Japanese ferns
data available from outside Jap an are only (Filicales). Univ. Tokyo Press，T okyo.
Nakato N. 1989. Distributions and mo中hologicalvaria-
those recorded by Tsai and Shieh (1983，19 85)
tions ofdiploid and triploidcytotypes of Pteris cretica
and Weng (1985)，e ach based on as ingle L. in the Kanto District. J. Phytogeogr. Taxon. 37:
material from Taiwan and China，re spectively， 113-119.
and reporting the base number of x=36. It is 一一一一 1996. Notes on chromosomes of Japanese
pteridophytes (4). 1. Jpn. Bot. 71: 163-167.
noted that Tsai and Shieh (1983，1 985) re
同 一一一-and Masuyama S. and Mitui K. 1983. Studies
ported the number of n=36IV (36 quad-
on intraspecific polyploids of the fern Lepisorus
rivalents) at meiosis with the normal produc thunbergiαnus (1). Their distributional patterns in
向
tion of 64 spores per sporangium. Extensive Kanto districts and the occuenceof new cytotypes.
町
chromosomal studies，es pecially from outside 1. Jpn. Bot. 58: 195-205.
Takamiya M. 1996. Index to chromosomes of Japanese
Jap an，ar e needed to understand the cytologi
町 Pteridophyta (1910-1996). Japan Pteridological So-
cal evolution in this species. ciety，T okyo.
一一一一，Watanabe M. and Ono K. 1994. Biosystematic
1t hank Dr. D. M. Britton，U niversity of studies on the genus Isoetes in Jap an I. Variations of
the somatic chromosome numbers. J. Plant Res. 107:
Guelph，fo r his kind linguistic review of the
289-297.
manuscript. 1a lso thank Mr. Koichi Ohora
Tsai 1.-L. and Shieh W.-C. 1983. A cytotaxonomic
(WakayamaPref.)， Mr. Takeshi Suzuki (Hyogo survey of pteridophytes in Taiwan. 1. Sci. Engin. 20:
Pref.) and Mr. Sadao Tsutsui (Fukuoka Pref.)， 137-158.
一一一-and一一一一， 1985. A cytotaxonomic survey of
for supplying some materials.
the fern family Aspidiaceae (sensu Copeland) in
Taiwan.1. Sci. Engin. 22: 121-144.
References
Weng R.-F. 1985. Observation on chromosomes of
Ching R.-C. 1963. A rec1assification of the family
some Chinese ferns. J. Wuhan Bot. Res. 3: 367-370.
Thelypteridaceae from the mainland of Asia. Acta
124 植物研究雑誌第73巻第3号 平成10年6月
中藤成実:ヤワラシダの異数性
ヤワラシダにはx=34の4倍イ本，および、x=36の2 体は正4倍体から単純に2本の染色体が欠失したも
倍体と 4倍体が報告されている.今回，日本の 19 のではなく，正4倍体の染色体が融合したために生
産地から採取した24個体について染色体を観察し じたのではないかと推察された.岩槻 (1995)は
たところ， 2産地からの3個体は2n=136，17産地 ヤワラシダを， Thelypteris亜属Metathelypteris節に
からの21個体は2n=134であった.前者はx=34の 分類した.この仲間の染色体数は現在までヤワラ
正4倍体，後者は異数体で低4倍体と考えられる. シダを含め4種で調べられており，染色体基本数に
本研究においてはx=36に基づく染色体数は観察で ついてx=31，34， 35， 36，倍数性では2倍体と4倍
きなかった.正4倍体と低4倍体の染色体の長さを 体が知られている.これは この仲間の細胞学的
測定したところ，正4倍体では136の染色体長は漸 進化には倍数性ばかりでなく異数性が重要な役割
次変化するが，低4倍体では134の染色体のうち2 を演じたことを示している.
本の染色体が特に長かった.このことから，低4倍 (東京都立国分寺高等学校)
第73巻2号正誤 Erratain Vol. 73 No. 2
頁(Page) 行(Line) 誤(For) 正(Read)
104 trilobed or tri10bed to
106 ↓ 2 var. himalaica Hara var. himalaica H.Hara
108 ↑ 4 (Hayata ex Honda) (Hayata)
108 ↑ 6 Hayata ex Honda Hayata in Honda
108 Hayata ex Honda Hayata
109 ↓22 Hayata ex Honda Hayata
110 ↓10 Nakai ex Honda Nakai in Honda
111 ↑ 6 (Na kai) Hara (Nakai) H.Hara
111 ↑16 (Nakai) ex Honda Nakai in Honda
111 ↑21 Thunb.8)e x Murray Thunb.8)i n Murray
112 ↑24 Nakai ex Honda Nakai
113 ↑24 Heloniopsis Heleniopsis
114 ヤマシマショウジョウノてカマ ヤクシマショウジョウノくカマ
