OOOI-･6799 Acta Phytotax. Geobot, 47 (2): 169-1.72 (1996)

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OOOI-･6799 Acta Phytotax. Geobot, 47 (2): ^169-1.72 (1996)

Karyomorphology in Two Species ^of IVesaea

(Lythraceae; Lythroideae)

KAZUO OGINUMAr

^and

HIROSHI TOBE2

'cotlege

of

^ChildDevelopment,Kochi VVomen's University,Kbchi 780;^2fuculty

of

^{JntegratedHuman}

Studies,i<yoto

Uhiversity,

K>,oto606-Ol

Abstract.

Karyomorphology

intwo Airican species of

Nesaea (N.

^{aspera and IV/ cordata) of}

Lythraceae wa$ studied forthe firsttime using meristematic cells of root tips.Chromosome numbers are

2n

⁼⁼ 10

in

Nesaea cordata and 2n

==

_{30 inN.aspera; 2n}=:: 10 inN, cordata is the

low

¢stnumber inthe genus,

The

two species aTe similar inhavingthesimple chromocell- ter type at interphaseand a karyotypecontaining chromosomes with secendary constriction.

Based on the present^{and earlier}inforrnation,we determined the chromosome basenumber of ?Vesaeato

be

x ⁼⁼

5,

a number derivedinLythroideae where most genera ^are known to

have _x=8. Relationshipsof 7Vesaea with several other genera with x;5

(Diplusodon,

Lythrum, and Peplis)arc also briefiydiscussed,

Key

words: chromosome, Lythraceae,Lythroideae,Nesaea ReceivedJuly30,J9P6yaccepted

October

21,J996

^Lythraceae

^sensu

^lato,

^comprising

³¹ genera in four

subfamilies,

have

been

studied relatively well with respect

to

chromosome numbers.

Both

Duabangoideae (Duabanga)

^and

Sonneratioideae (Sonneratia)

^are

^known

to have

x ⁼

12, Punicoideae (Punica)

^{x =}

^8,

^and

Lythroideae (28 genera)

^x

=

8

or

5 (Tobe

^{et al.,}

^{1986; Graham}

^{et aL} ,

1993a). Within Lythroideae,

of

28 genera 14

are

known to

retain

the primitive base

^number of

the

sub-

family

x=8, and

three (Diplusodon, ^Lythrum

^and

^{Puplis) have}

^x:=:5

(Graham, ^{1992). Base numbers}

^stillremain

^{to be} determined for

seven

genera ^including Nesaea.

AJesaea

comprises

50

species

distributed in South Africa

and

Mexico

(Graham

^{et al.,}

^{1993b). Earlier} information

on chromosome numbers of

the genus ^is

^restricted

^{to two}

^species:

^{N. trijZora} (L. ^{f.) Kunth} (2n

^=:

^46,

Tobe

et al.,

1986),

and

N. Iongipes A. Gray (2n

^{= ca.}

^{50, Graham, 1977).}

In this paper

^we

present ^the first

report on

the

chromosome number and morphology at

different

^stages of cell

division in two

additional species,

?Vesaea

aspera

Hiern

and

^cordata

Koehne,

and

determine the chromo-

N.

some

base

^number of

the genus.

Materials

and

Methods

Viable

^seeds of

Nesaea

aspera

Hiern (R. ^{B. Drummond 11446, SRGH)}

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170 Acta Phytotax. Geobet. Vol, 47

and

N.

cordata

Koehne (R. ^{B. Drummond 11447, sRGH)}

^{were collected}

^at

Kwe Kwe in Zimbabwe. Somatic

chromosomes were examined regarding at

least three

cells of root

tips. Methods

of

pretreatment, fixation,

macera-

tion,

and staining were

published in detail

elsewhere

(Oginuma

^and

^Naka-

ta, 1988). The

categories of chromosomes

described

on

the basis

of

the position

^{of a centromere}

fo11ow Levan

et al.

(1964).

Results

and

Discussion

Interphase

nuclei

have

chromatin

threads

and many chromomeric

gra-

nules.

Eight to ten (?Vesaea

^{cordala) or}

^{20 to 25} (N.

^{aspera), ellipsoid or}

round, condensing

blocks

alse appear

in the

nucleus

(Fig. ^{1, Nesaea}

^corda-

ta; Rg. 4, IV.

aspera).

The interphase

nucleus

is thus

of

the

simple chro- mocenter

type (for typification

_see

Tanaka, 1971, 1980).

At mitotic

metaphase, chromosomes are small and

gradually

^vary

in length from

about

1.1ptm to 2.5ptm in 7Vesaea

cordata

(2n

⁼

^10),

^and

^from

1.2#m to 2.1ptm in N.

aspera

(2n

⁼

^{30). In iVesaea}

^{cordota, six of}

^{the ten}

chromosomes have

centromeres at median

position, ^{two have}

centromeres

at submedian

position,

^and

^{the two} largest

chromosomes

have centromeres

at median

position

^{and also a}

^secondary constriction

on a short arm

(Figs.

-

ee- eeff ee ^{twee ge}

¢

asmeasas ^eees

geee ^{, .,as.tee @ tw} ee ^{. ew , w ee ./ xe wa " X ee} _ee

^ex

tt .t' .t vttt . tt. t..

FJGs.1-6.

mafii ^"

ee

^','

l,eeca

tt t .tt tt t tt

@･

^{･:･･･-:･:}

@ ^.

"sY

'"ti}''

r x-･

be

k,

et

t'i

"egnW

"' st

t:;t:t.

t

ⁱ

^{･ ･pt,iN. . i-}

t.･"･

"-'

k

e

xY

l･

iC

i- ^,.

"

"

ees.-

l

^.･,

･ e

Somatic chromosomes of Nesaea at

interphase (1

^{and 4)and metaphase}

(2, ^3,

^5,

^6).

^1-3.

N,

contata

(2n

⁼⁼

^{10). 4-6. ?V.}

^aspera

(2n

^{=: 30).Figs.3and6are drawingsof the}chremosomes in Figs.2 and 5

(photographs),

respectivcly Arrowheads

indicate

chromosomes with thesecondary constriction.

ArTows

show chTomosomcs with submedian centromeres. Scale⁼ 2ptrn.

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December 1996OGINUMA &

TOBE: Karyomorphology of

Nesaea 171

2, 3). In Nesaea

aspera

(2n

⁼

^{30), 18}

^of

³⁰

chromosomes

have

centromeres at median

position,

^{and six}

have

centromeres at submedian

position. ^The

remaining six chromosomes with

the

secondary constriction are slightly

different from

one another

in

chromosome

length

and

position

^{of centro-}

meres;

the four iarge

chromosomes

have the

centromeres at ^{median and} submedian

position,

respectively, and

the two

medium ones at submedian

pesition (Figs. ^{5, 6).}

When Nesaea

aspera

(2n

⁼⁼

^{30) is}

^{compared with}

^N.

^cordata

⁽²ⁿ

⁼⁼

^10),

they

resemble each other

in having the

simple chromocenter

type

at

in-

terphase

and a similar

karyotype

at metaphase.

In both

species,

the fre- quency ^of chromosomes

^with centremeres at median or submedian

position but

without

the

secondary constriction and of chromosomes

with the

secondary constriction

is 60%, 20%, 20%,

respectively.

Results

^of

^the present

^{study, combined}

^{with the}

^earlier

information,

showed chromosome numbers of the four species in total: 2n

⁼

10 (Nesaea

cordata,

this

study),

30 (N.

^aspera,

^this

^study),

⁴⁶ (N.

^trijlora,

^Tobe

^{et al.,}

1986),

and ca,

50 (IV. ^{Iongipes, Graham, 1977).} Information

available sug-

gests that the base

number of

Nesaea is

x=:

5. The

secend author

(H. ^T,)

now considers

that 2n:=46 in Nesaea

^{trij7ora might}

have been

^an

erroneous count of

2n

⁼

40, because the long

arms

in

a

few (perhaps

^{six of}

eight)

chromosomes with secondary constriction

tend to be

counted as separate chromosomes.

The

^{chromosome number of}

Nesaea trijlora

re-

quires

reconfirmation

in future.

The base

number x=:5

is

obviously a

derived

one

in the family. In

addition

to IVesaea, three

other

genera Diptusodon, Lythr"m,

and

Peplis have

x ⁼⁼

5. The

shared

base

number suggests

that these four genera

^may

have been derived from

a common ancestor with x ⁼⁼

5. Such

close re-

lationships

among

these genera

^{are suggested}

^by

^{cladistic analysis also}

(Graham

^etal.,

^{1993b). In fact,}

^according

^to

^{one of}

^five

mostparsimonious cladograms

(Graham

^{et aL,}

^1993b, p. 23, Figure 6),

within

Lythroideae

a

clade comprising

Diplttsodon, Lythrum, Nesaea, Peplis, Ammania, Rotala,

Hionanthera,

and

Didiplis is

supported

by the

absence

of

septate wood

fibres

and

the presence

^of

two-whorled

stamens, although

in the latter four genera ^{the base}

^number

is

either x==8 or not

determined yet. Chromo-

some numbers

have

not

been

used

for the analysis of generic

relationships so

far (for

^{example see}

^Graham

^{et at.,}

^{1993b). However, if}

^more

^{data be-}

comes availabie

from

other

genera in future, it

will

be

expected

that

we

can

use

that

^character

also in considering generic

reiationships

and to see

how the

chromosome

base

number ^changed

in the

_{major evolutions} of

Lythraceae.

We

are

grateful

^to

Peter H. Ruven

and

R. B. Drummond for

theirefforts

in

collecting viable $eeds of

Nesaea

which were used

in

thisstudy.

References

Graham, S, ^{A. 1977. The American}

^{species ef}

^Nesaea (Lythraceae)

^{and their}relationships

The Japanese Society for Plant Systematics

NII-Electronic Library Service

The 　Japanese 　Sooiety 　for 　Plant 　Systematios

172 Acta

　

Phytotax，

　

Geobot 。 Vol ．47

　 　 to

Heimia

　and 　

Decoden ．

　

Syst．

　

Bot ．2

：

61− 71．

　　　　．1992．New

^{chromosome 　counts 呈n}

Lythraceae−

systematic 　and 　evolutionary 　

im − 　　 p ^賦

^cations

．



Acta

　

Bot ，



Mex ．17

^：

45− 51．

　　　　 ， K ．



Oginuma ，



P ．

　H

． ．



Raven

　and 　H

．



Tobe 。1993a．

　

Chromosome

^numbers

^jn



^{Son −}

　　

^{neratia 　and}

Duabanga （Lythraccae

⁵

．の

^{and 　their　systematic}signiflcance

、

　

Taxon

　

52

：

　 　

35− 41．

　 　 　 　

，J．



V ．

　

Crisci

　and 　

P ．

　

C ，

　

Hoch ．1993b．

　

Clad

｛stic　analysis 　of　the　

Lythraccae

　sensu

　　lato



based

　on 　morphological 　characters

．

　

Bot ．

　

J．Linn，

　

Soc ．113

：

1− 33、

Levan

_，　

A ．

_，　

K 。

　

Fredga

　and 　

A ．

　

A ．

　

Sandberg．1964．

　

Nomenclature

　

for

　centromeric 　

position

^of

　 　

chromosomcs

．



Hercditas



52

^：

^{201− 220 ．}

Oginuma ，



K ．

and 　

M ．

Nakata

．

1988

．



Cytological



Studies

on　Phanerogams 

in



Southern



Peru

_，

　　1． Karyotype

　of

． 4caena

　oレatifolia

．

　

BulL

　

NatL

　

Sci ．

　

Mus ．

　

Tokyo ，



Ser ．

　

B ，



VoL

　

14

：

　 　 53− 56 ．

Tanaka

_，　

R ．1971．

　

Types

　of　resting 　nuclei　

in

　

Orchidaceae．

　

Bot ．

　

Mag ．（ Tokyo ）84

^；118

− 122．

　　　　 ．1980．The



karyotype．

　

In

　

H ．

　

Kihara （

^ed

． ）

，　

Plant

　

Genetlcs

　

1

：

335− 358 ．

　

Shokabo

_， 　 　

Tokyo

_（

In

　

Japanese

_）

．

Tobe

，　

H ．

_，　

P ． H ．



Raven

　and

S ，



A ．

　

Graham ^{． 1986．}



Chromosomo

^counts

^for

some 

Lythraceae 　　

^sens

，

　str

．（Myrtalcs），

^{and 　the}

base

　numbcr 　of　thc　

family，

　

Taxon

　

35

：

13− 20，

摘 要

荻 沼

一

_男¹

・ _戸

_部

　

^博2：

¹

^＞esaea 属 （ミ^ソハ ギ 科 ミ^ソハ ギ 亜 科 ）

2

_種の核 形 態

　

Nesaea

_属は

4 亜

科

31

_属か

ら

な^{る ミソハ} ギ 科^の

1

_属で

，

最 も大

^き

な

^亜

科 ^ミソハ

^{ギ 亜}

科^に含 ま れ

る

。 主^に南^アフ

リ

カ

と

メキ^{シコ に}

50

_{種 が 分 布}

し

て い

る

。 これ ま^で

2

_種に^{つ い} て染 色 体 数^の報 告

^が

あ^る

^が

，

ま だ

_， 属^の染 色 体

^基

本 数^は確 定^{し てい}

^な

^い 。 この研

^究

^{で は}

，

^{アフ リ カ}

^産

の

2

_種

Nesaea



・

_cordata 　

Hiern と N ．

　as_ρera　

Koehne

の

核

^{形 態}

^{が 初 め て}

調^べ

^{ら れ た}

^。

^そ

^の

結 ^果 ， N ．

cordata

は 2n ＝ 10，1V．

_{鰐 ρ}εrα

は 2n ＝ 3

  を

も

^つ

が ，2

^{種 と}

^{も 問}

^期

^に “

_simple

　chromocen

− ter

　type

”

を

示

^し ， ^二

次 狭

窄 ^{を も}

^つ 染 色

体

^を

含 ^む （ 2n ＝ 10

^の場 合

^は 1

対

，2n ＝ 30 の

場 合^は

3

対

）

点^で巾期^の 核

^{型 は}

良

^{く 似 て}

^い

^る

^こ

^{と が}

分

^か

^{っ た}v この

結

果^に基^づ き， こ

れ ま

^で 知

ら

^{れ て}

い

る 報 告 と 合 わ せ ， Nesaea 属

^の染 色 体 基 本 数 を^x

・ ・5 と

確 定

し

^た。

ま

^た

，

^ミソハ

^{ギ 亜}

科 （

28

属 ）

^の

^原

^始

^{的 染}

^{色 体}

^基

^{本 数がx ＝}

8

であ^{る こ と が}推 定

さ れ

^{てい る た め}，

N

蜘 8α属

と 同

様^の派 生 的 基 本

tk

　x

・ ＝5

を も^つ

Diplusodon

_，　

Lythrum （

^ミソハ ギ 属 ）

，

_{理 砂}⁵

^と

^の類 縁^{につ い て} も議 論

し た

。

（

¹

^{〒 780}

高 知 市 大 原 町

132 　

高 知 女 子 大 学 保 育 短 期 大 学 部 ^：2〒

606−Ol

京 都 市 左 京 区 吉

^{田 二}

本 松 町

　

京 都 大 学 総 合 人 問学 部 自然 環 境 学 科

）

N工 工

一

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