]
ap.J.Phyco.
l(Sorui)29・79‑
80.June20，1981

A sex chromosome inCymαthaer
ejαponicα M IY ABE et N AGAII‑!iroshi YABU* and YoshiakiSANBONSUGA中市Fac
uL
ty0
1Fis
her
ies，Hoklwi
do Univers
ity，Halwda
te，Holzl
wido，041Japan
HokkaidoRegionalFi
sheries Re
search Labora
tory，J(ushiro，Hokkaido，085Japan
本村J(eyJndex Words: Cymathaerej
apon
ica;Phaeophyta;sexc
hromosome.

Thegametophytesand sporophytesu
sedin culture were obtainedf
romf
er
t
i
lef
r
onds
o
fCymαthαereJ
ραonicacolectedin10met
er
s
Raus
ui
neasternHokkai
dodept
hatKyoeicho，on September 26， 198
0. Th巴 fr
onds werefixed with acetical
cohol(1:3)and stai
nedby the method recom mended by W ittmann(1965) f
or cytologi
cal obser
vations. The
haplo
id c
hromosome number r
anged fr
om
28‑
34i
nt
hec
els of femal
e gametophytes(Fig. 5)and a reliable numberse
ems to be
33，as shown in Tabl
e1
. The presence. Chromosomec
ounti
nfi
f
ty ce
ls ofTab
le1
femal
egame
top
hyt
巴5 of Cymat
haerejaponicaNUlllb
erofc
hromosome (n)28 293
0 31 32 3
3 34Numberofcel

4 3 6 7 91
4 7/、、〆
25o
fa large chromos
ome has been r
eported1963， 1965) in several Lami‑
by Evans (nariaceousspec
iesf
romt
heAt
lant
ic，among
which Saccorhi
zα tolyschi
des wass
hownt
o

367

YABU，H.andSANBONSUGA Y

808Figs.1‑
10. M
it
osisi
nt
hegam巴tophytesa
ndsporophytesofCymalhaerejaponicaMiyabeetNa
ga.
i 1‑4. Sexchromosome (arrows)atmet
aphaseint
hecelofm
alegametophytes;
5. Chromosomes int
hec
el o
ff
emal
egametophyte; 6. Metaphase (2n)int
hes
porophyte
atone‑
cele
dstage;7‑10. Sexchromosome (arrows)at met
aphaseint
he spcrophyte
sof
igures，X 2，300one‑cele
dstage. M
agni
fication;A1 fhave a markedl
y large X‑
chromosome int
he female gametophyte. The w
ell defi
nedmetaphase fi
gurei
nthe male gametophytesi
n our material usualy proved to b巴 one
U‑shaped large sex chromosome (Figs.1‑3).
This speci
al chromosomes
ometimesappears
by:early prophase by theprocessofhetero‑pyknosis and is discernible in mid‑metaphase (Fig.4)and anaphase as alarge
chromosome stained somewhat deeper thanthe other chromosomes.
Numerous young sporophyt
es，consistin
gof from one tofiv
ecels，devel
oped after
14days in cultu
re under 1
3C temperatur
e
provi
de
df
in
e dividing nu
clei wit
hdiploidchromosomes in which t
he s
exchromosome
was occasionaly distingui
shed (Figs.7‑10).
Recently FANG et αl.(1978) descri
bed
the occurrence of some nu
clear abnorma‑
li
t
ie
si
n the parthenosporophyt
巴s of Lami‑nαnα japonica. Among more than fiv
e0簸

hundred sporophytes with divi
di
ng n
u
clei
obser
ved we coulds
ee ni
n巴 parthenospo・ropbyt
es at the two‑celed stage with
haploid chromosom巴sin each cel.
l Al
loft
hesenuclei were normal and lacked tb巴large sex chromosome intheir cbromos
omecompl
ement

References.V. 1
963. Alargechromosome int
heEVANS，LLaminariannucleus. Nature1
98:215965. Cytologicalstu
di巴s int
h巴EVANS，し V. 1
Laminariales. Ann. Bo仁 ， N.S.2
4:5
4
1‑
652.
.C.，TAI，C.H.，00，Y.C.，TSUEI，C.C.
FANG，T.C.1
978. Someg
eneticobser‑and CIEN，Tvationsont
hemonoploidbreeding of Lωnl‑
nariajaponica. S
cientiaSin
ica，21:401‑
408WITTMANN.W.1
965. Aceto‑
iron‑
haematoxyl
in・chloral hydratef
or chromosome staining.
Stain Te
ch.40:161‑164~~~ 本 ・三 本菅善 昭 ** . アッパ スジ コンブの 性染色 体

北海道j，li臼で採集した アジハスコンブを培養 し， 配{肉体と 芽胞体の回定を行い染 色体を調べた o ~W 性体で中土 n=約 33の染色体数が得 られた o uJU
生体と芽J包体は通常 1ケの大きい性染色体を有するが， この染色体は a:li
性体では U字状を呈することを確かめた。(事041函館市 港 III
J3一 1‑ 1 北海辺大学水産学部 付 085釧 路 市 経 恋 116北海道区水産研究所)