i.gi･s local populationdiversity (malvaceae)

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The Society ofVegetation Science

Vbgetation Science M: 19'2S, 2oo7 19

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Local variation

(Malvaceae)Hiroki NAKANISHIi",

and Asami TAKAKI3

and population

Kozue NAKANISHI2

diversity of Hthiscushamabo

iBiological Laborator)', Faculty of Education, Nagasaki University

21nstitute of Biology, Faculty ofEnvironmentat Studies, Nagasaki University

"Marine Giken Corporation

Flower and fi'uit morphologies of HZbisczas hamabo SieboEd et Zuoc, were investigated in nine populatjons,five on the Omura Bay side and four on the ocean side ofthe Nishisonogi Peninsula in Nagasaki Prefecture,southwestern Japan, and were compared among populations, The moiphological characters investigatedwere petal length, petal width, style length, anther-stigma distance, anther-anther distance, number ofstainens,

fi;uit ]ength, fruit diameter and potemial number of seeds per fruit. Observed variations were mainly among

populations, and each population had specific characters in fiower and t'rui't morphologies. Populationdiversity is important for conservation and restoration in Hthiseus hamabo communities. Petal length, petalwidth, anther-anther distance, number of stamcns, fruit length, fiJuit diameter and numbeT of seeds in

populations on the Omura Bay side were significantly smaller than each of those characters on the ocean side,

but anther-stigrna distance was longer. These characters may indicate that the populations on the bay side

had evolyed in the pollinator-rich environment and become to avoid selfLpollination,

Key words: Hthiscus hamabo, morphological character,Omura Bay, population djversity, variation

asi INTRODUCTION

Among the many morphological characters of plants,fioral characters are the most important in tenms of repro-

duction because fioral morphology directiy infiuences

breeding success. For examp]e, the Iength of the corolla

tube directly {nfluences cross-pollination with regard to

pollinators (Nilsson r988), and the distunce berween

anther and stigrna affects selfing (Kudo et al, 1998; Klips& Snow t997). Geographical yariations in floral mor-

phology may lead to the differentiation of new species.

Studies on the variations of floral morphology provide uswith various usefu1 information such as reproduction,

relation to potlinator and evolution (inoue 1988, 1990;

Suzuki 1992; Klips & Snow 1997; Kudo et al, 1998;Suzuki et al. 2002), Recent investigations on interspeclfic

yariations in local areas have chieffy been done by molecu-

lar analysis (e.g. Kitarnura et al. 1997, 2005; Arzate-Fer-nandez et al, 2CX)5), but not by floral morphology, which

is related te breeding success and polljnators. Ifa popula-tien with difTbrent floral characters were to become separat-

ed, it might cause itse[f to a ncw species,

In conservation ecology, biological diversities are con-

sidered to consist of four levels: genetic, species, ecosystem

and landscape diversities (Noss t990; Washitani & Ya-

hara 1996) . Tbe population diversity may be also impor-

tant in conse]Nation ecology. Recently, fbr the restoration

of vegetation, native or domestic species instead of alien

species, furthermo]re Iocal plants (home plants) rather

than native or domestic species, are considered to be

important (Kobashi 1984; Watanabe et a]. 1996; Tsuji

2001, 2002), That may be why morphological and

genetic variations in local population are important for

maintenance of species diversity.

Hthiseus hamabo Siebold et Zucc. (Malvaceae) is the

northernmost semi-mangrove plant distributed in south-

western Japan and Jeju lsland ofKorea (Nakanishi I979,

1985). This species often forms a dominant scrub com-

munity in estuaries, down-stream, along the shore of'inlets

and coastal lakes, Suitable habitats have been destroyedby reclamation, river conservancy and shore protectionwork; therefore this species has been described as an

endangered species in the red da,ta book of many prefbc-tures where it is distributed. Most ofthe communities are

fragmented and isolated, and are composed ofpopulations

containing fewet than 50 individuals of Hlhamabo

(Nakanishi 20oo, 2oo1).

This study aims to account fbr observed local variationsand population diversity of Hl hamabo, especially by thecotnparing bay side and ocean side populations with

SBiological

Laboratory, Faculty of Eduetttion, Nugasakj University, Bunkyo'machi 1-I4, Nagasaki 852-8521, Japan,nagasaki-u.ae.jp

The Society of Vegetatio]i Science ee Received january IQ. ZO06/Accepted April 19, 2007

E-mail: hiro-nak@net

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The Society ofVegetationScience

20 ifegetation Science Vol. 24, No, 1, 2007

regard to fiower and fruit morphologies, We also intendto provide practical information about the conservation of

this species,

;･ee MATERIALS AND METHODS

Study sites

Field studies were done in both the Omura Bay side and

the ocean side of the Nishisonogi Peninsula in Nagasaki

Prefbcture, westem Kyushu, Japan (Fig, 1), The Omura

Bay, which covers an area of about 360 km2, is about 26

km long from nonh to south and ].1 km ]ong from east to

west, The coastline of the bay is largely irregular and 360

km long, The depth of the water is 14.8 m on average,

and with a maximum depth of 54 rn (Iizuka & Takita

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Fig.1. Map showing the localities investigated. 1:

Susebol 2/ Omura; 3: [sahaya; 4: Tarami; 5: Togitsu;

6: Oseto; 7: Nagushljima; 8: Isanoura; 9: Oshima.

1985), The area was abasin that turned into a1ake, and

the sea-water flewed into it in the 1atest transgression

about 7000 years ago, forming the present bay (Matsuoka2004). The bay, which is nearly closed, is connected

through two narrow struits, Hario Seto and Ha{ki Seto, to

Sasebo Bay. Thus, the bay area has only minimal mari-

time influences, such as sait spray and wave action. With

the exception of saEt marsh plants, only a small number of

coastal plants are distributed on the bay side. HL hamabois wi'dely distributed in the bay side, but the dominantcommunity is resnicted, On the other hand, the ocean

side of the Nishisonogi Peninsula is greatly infiuenced by

the sea, H. hamabo is restricted to the down･'stream and

shore of inlets where it is pretected from wave action.

Study sites were ehosen at populations with more than

10 individuttls of HZ hamabo. Five populations were

selected on the Omura Bay side, Sasebo, Omura, Isahaya,

Tarami and Togitsu, and four populations were selected on

the ocean side, Oseto, Nagushjjima, isanoura and Oshima

(Fig. I and Table 1) . Field experiments were carried out

in 2oo3 on Isahaya, Tarami, Togitsu and Nagushijima, in

2CM4 on Sasebo, Omura and lsanoura, in 2oo5 on Oseto

and Oshima.

Measurements

Thirty fiowers were collected in mid-July from five

individuals respectively, which were randomly selected

from each population, The total number of individuals

investigated was 45, In the laboratory, six floral characters

were measured for al1 flowers collected (Fig.2): petal

length (PL), petal width (PW), style length (SL),anther-stigrna distance (ASD) which is the nearest dis-

tance between the uppenmost part of anther and the lowest

part of stigma, anther-anther distance (AAD) which is

Table 1.LocaJity and population size of llthtycus hamabo.

No, Popu]ation LoeulitvNumber of

individualsLocation ot' stand Region

1234

5

6

7

8

9

SuseboOmuraIsahayaTarami

Togitsu

Oseto

Nagushijjma

lsunoura

Oshima

Miyaxu-cho, Susebo City

Koriguwa, Okitago, Omura City

Nakiri, Kuyama-cho. Isahaya City

Nozoemyo, Tarami-cho, Nishisonogi

gun (lsahaya City)

Shishigawa, Togitsu cho, Nishisonogi-

gunYukinoura, Oseto -cho. Nishisonogi-gun

(Saikai City)

Nagushijirna, Saikai-cho, Nishisonogi-

gun (Saikaj City)

Isanouragawa, Saikai-cho, Nishisonogi-gun (Saikai City)

Noda, Oshima cho, NishisonogL-gun

(Saikai City)

1530l530

10

10

30

50

15

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sidebay

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bay side

ocean side

ocean side

ocean side

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Variation and divcrsity ef Hthtscus hafnabo 21

the distance between the lewest anther and the uppermost

anther and which reveals the length of filamental tube

measuring a rule, and number of stamens (NS). As the number of flowers investigatod, mature frujtsexcluding those that had been bored through by moth

larva were collected in 'mid-September, Fruit length

(FL) and fruit diameter (FD) were measured by using

the vernier caliper, and potential number of seeds

(=number ofovules, PNS) per fruit was obtained by thesum of mature and immature seeds.

Statistical analysis

Variations among individuals within population,

among popuLations and between two regions, bay side andocean side were statistically tested fer each character, Thehomoscedasticity of data distributions was detected byBartlett test (P<O.05) in advance, An one-factor

ANOVA was used when the homogeneity of variances was

detected; otherwise, the Kruskal--Wallis test was used

when heterogeneity of variances was detected. To com-

pare the cornbination differences between pair of individ-

uals and pair of populations, Post-hoc test was done byusing the SchefTe's F test, We used the software Statcel

(OMS Pub. Co., Saitama) ,

## RESULTS

Variatiens of populations and individuals

Individual variations of the nine characters investigated

are shown in Fig. 3. In the comparisons of variations

among individuals within population and among popula-tions for each character, significance values determined byANOVA or the Kruskal-Wa]lis test are shown in Tables2 and 3. The results of post hoc comparisons between

pair of individuals and pair ofpopulations are shown with

letters in Fig. 3.

The differences among individuals in the Omura and

lsahaya populations were statistically sigriificant for all

characters investigated, Those in the other populationswere not significant for some characters (Table2). The

difierences among populations was fairly significant for all

characters (Table 3). Descriptions of each character are

as follews:

Petal length: PL (Fig. 3-A): Individual averages were

from 44,9 to 58.1 mm, The shortest population was the

Omurapopulation (44.9to 51.I mm) and thelongestwasthe Isanoura (54.5 to 58,I mm). All the populations on

the ocean side were longer than 50 mm, but more than half

of the populations ofthe bay side were shorter than 50 mm

(Fig. 3-A, Table4). The Isahaya poputation was Ionger

than the others on the bay side. The Omura populationvaried greatly and consisted oftwo individual groups withlonger and shorter petals (Fig. 3-A).

Petal width: PW (Fig. 3-B): Individual averages were

from 44.9 to 60.0mm. As the petal length, the shortest

population was the Omura population (44.9 to 52.7 mm)

and the longest was the Isanoura (56,7 to 60,Omrn),Petal width variation of each population was greater than

petal length (Fig. 3-A, B, Table 4). The Sasebo and the

Omura populations were shorter than the others, and most

individuals were shorter than 50 mm.

Style length: SL (Fig. 3-C): Individual averages ran-

ged from 21.1 to 27,3mm. There was little variation

among individuals. The differences among individuals inthe Tarami, Togitsu and Oseto popu]ations were not fbund

(Tuble 2),

Anther-stigma distarice: ASD (Fig, 3-D): lndividualaverages were 1.1 to 5.5 mm. The longest population wasthe Taranni, which was 4.6 to 5.5 mm on average and the

shortest one is the Oseto population, which was 1.t to 2,7mm. In the Oseto populatjon we observed that there weresome flowers whose anther-stigrna distance was 0 mm; theanther was attached to the stigma.

Anther-anther distance: AAD (Fig. 3-E): Individualaveruges were 10.0 to 18,O mm, The shortest populationwas the TaiJarni, which ranged from 10.5 to 12,1 mm on

average. With the exception of the Oshima population,the anther-anther distances in populations on the ocean

side were longer (Fig.3･-E). The differences of theanther-anther distance among individuals within popula-

A B

eg FD

c

FL

Fig. Z Measured parts offlower and fruit of

Hthtscus hainabo. A: peta]. PL, petal length; PW, petal width, B: longitudinal

section of the central portion of fiower,

SL, style length; ASD, unther-stigma distance; AAD, anther-･ anther distanoe. C: t'ruit. FL, fruit length; FD, fruit diameter.

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22 Vbgetation Science Vol. 24, No. 1,2007

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24 Vegetatien Scienee Vol. 24.No. 1. 2D07

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26 VlegetatienScience Vol. 24, No, 1,2007

Tabte 4.Cotanparison of nine fiower and i'ruit characters(mcan ± SD)between both sides.

Characters Bay side Oeean side F

Petal length (PL)Petal width (PW)Style length (SL)Anther-stigma distance (ASD)Anthcr-anther distance (AAD)Number of stamens

Fruit length (FL)Fru{t diameter (FD)Potential number of seeds

49.9+2,4mun

51.6±3.6rnm

24.1 ±. L3 mm

3.9±O.9mnn

13.4± 1.9mm43.1 =F 8.626.9

± 1.8mm

15.3±O.7mm

49.4=1 4.2

55,O± l.9mm

542±3.3mm24.41. I.3 mm

2,9±O.9mm

IS,S± ].7mm

43,8±8.629.1

± 2.2mm

16.2tl.Omm

54.0±3.9

51226**ts

6.352s

O.894nsI4,500.*15,097:,･

O,096as12,907**10.893*

9,576e

F/ value by ANOVA [est, significant levet:.P<O,05i

**P<O,OOI:

*S*P<O.Ooo1,ns,

non-s{gnificant (i.e.P>O.05)i

tion were statistically significant in all populations (Table2).

Numberofstamens: NS (Fig.3-F): Thevariationwas

great and individual averages were 27.1 to 61,4. Thedifferences among individual averages in the lsahaya, OseLo

and Nagushijima populations were great, respectively

(Fig, 3--F, Table 2) . These populations had two individ-ual groups containing 1arge number and small number of

stamens (Fig, 3-F).

Fruit length: FL (Fig. 3-G): The variation was greatand individual averages were 22.4 to 32.6rmn, The

Omura population varied greatly, ranging from 22.4 to 26.4mm, and the Oshima population had little variat{on

(Table2) and ranged from 25,8 to 26Amm. With the

exception of the Oshima population, imit length of the

populat,ions on the ocean side was longer than 28 mm.

Fruit diameter: FD (Fig,3-H): Individual averages

ranged from 13.7 to 17.7mm. The Oseto populationvaried little (Tabie2), ranging from l4.4 to t4.7mm.

With the exception of the Oseto population which is

significantly di'ferent from other populations in the ocean

side, fruit diarneters of the populations on the ocean side

were longer than those on the bay side.

Potential number of seeds: PNS (Fig, 3-I): The vuria-

tion in average potential number of seeds was great, rang-

ing from 41,O to 60,O per individual. The value for the

Togitsu population was lower, ranging from 4t.O to 47.0.

Comparisons between the bay side and ocean side popu-lations

The averages fbr nine charucters investigated on both the

bay side and ocean side populations are shown in Table 4.

Petal length and width, anther-anther distance, fi'uit length

and diameter, and potenti al number ofseecls per fruit in the

populations on the bay side were significantly shorter and

fewer than those on the ocean side. The anther-stigma

distance on the bay side populations was significantly

longer than those on the ocean side,

significant differences in style length and

mens between both sides.

There were no

number of sta-

eei' DISCVSSION

For the nine characters measured on ilowers and fruits 7

variations of individuals within a given population were

diil'erent except fbr sorne characters (Fig, 3 and Table 2).

Variation among populations was larger than variations

within populations (Tables 2, 3) . Flowers and /E}/uits are

reproductive organs of plants, tmd are not easily aflbcted by

environmental conditions. The seeds ofHthiscus hamahoare dispersed by sea-currents (Nakanishi 1985). The

species could drift onto rocky coasts and aceidentally

become established there. In this study, selected individ-

uals were from populations containing more than 10individuals, thus it is apparent that their habitats providesuitable conditions for Hl hamabo growth. Therefore, the

variations of the characters observed may be reflected by

genetic variations. We sometimes observed that there

were two groups of individuals fbr several characters such

as anther-anther distance (Fig, 3-E) and number of' sta-

mens (Fig. 3-F) in some population. It may due to the

genetic factors.

Petal length and width, anther-anther distance, fruit

length and diameter ofthe populations on the Omura Bay

side were significantly shorter thati those on the ocean side

(Table4). However, the anther stigma distance was

significantly ]onger. It has been explained that the

evolutional process of difTerent sized fiowers of new spocies

might have been affected by the factor ofpollinator such as

species compesition and their densities (Inoue 1988;

Kudo et aL 1998). Klips & Snow (]997) reported that

flowers of Hthiseus laevts in the more northern part of

North America have a shorter anther-stigma distance than

in southern areas where the pollinators are richer. H

NII-Electronic




Variation and diversi"' of Jfibtscus hamabo 27

kamabo is known to be selFcompatible (Nakanishi &Kawara- Kiyoura 2004), On the Omura bay side, the

populations whose anther-stigma distances are longer may

be more diMcult in autonomous pollination, The Omura Bay area was originally a basin that was

fi11ed by an inflow of sea water through the straits at itsnorthern region about 7000 years ago, the warmer phase ofthe post glacial period (Matsuoka 2004). At that tirne

HZ hamabo might have spread te the bay area with other

maritime species, Hl hamabo populations currentl>, fbundin Omura Bay must be deriyed fi;om indiyiduals that

inhabited the ocean side at that time, and have become

geographically distinct from them. It is not clear whether

or not the 7ooO years of geographical diejunction since the

fbrmation of Omura Bay is lon.g. enough to have

differentiated such morphological characteristics among

the populations for Hl hamabo. Yoshida et al. (I995)recognized that tlte finless porpoise IVeophocaena

phocaenoidles of Omura Bay was a characteristic local

population by an investigation of its skull morphology,

There is the pessibility that characteristic populations of HL

hamabo have evolved in the pollinator-rich environment

of the bay area and become to avoid selffpollination.

Due to recIamation and shore protection projects, popu-lations of flZ hamabo have become separated and isolated.The findings of this study indicate that each population is

constructed of individuals that have characteristic flower

and fi'uit morphologies which can be used to distinguighthe popu]ations, Biodiversity has been described as an

attribute of fbur different levels of bioiogical organization:

genetic, species, ecosystem and landseape diversities (e.g.Noss 1990; Washitani & Yahara 1996). Genetic diveT-

sity refers to variations among the members of a popula-tion. To preserve the continuity of species, not only

genetic diversity but also population diversity is irnportant.

Recently, it is considered that in order to achieve the

restoration of vegetation, the use of local plants is more

important than native or domestic species (Kobashi I984 ;Tsuji 2oo1, 2002). For the conservation of Hthtscushamabo, it is necessary to consider the intra-population

variatien. In H hamabo, local plants specify a local

population ; in other words, it is not suitable to use plantsderived from other pepulations to achieve restoration.

X ACKNOWLEDGEMENTS

We are gratefu1 to Mr. Taro [waki, Miss Mioko Uesato,and Mis$ Miki Matsttda for their support in the field study

and measurements in the laboratory. We also thanks Dr.

Yasul(i Kikuchi, Faculty of Medicine, Nagasaki Univer-sity, for his kind belp to statistical analysis. Many thanks

are also due to anonyrnous referees who gave me va]uable

advice and criticism,

Xi- REFERIENCES

Arzate-Fernandez, A., Miwa, M,, Shimoda, T,, Yonekuru, T. & Ogawa, K, 2005, Genetic diversity of Mjyamasukashi-yuri

(Liaum maculatum Thunb. var. bukosanense) , an endemic and

endangered species aL Mount Buko, Saitama, Japan. Plunt

Species Biology, 20: 57'65.

Iizuka, S, &Takita, T, 1985. 0mura Bay. In: Coastal oceanog-

ruphy ofJapanese Lslands (eds. Coastal Oceanography Research

Committee, The Oceunographical Society of Japan) , 879-1 106, Tol(yo University Press, Tokyo (in Japanese).Inoue, K, I988. Patterns of breeding-systcm change in the Izu

IsSands in Campanula punctata: bumblebee-absence hypothesis.

Plant Species Biotogy, 3: i25-128.

Inoue, K, 1990. Evolution of mating systems in isEand populations of Canu)anula microdonta/ pollinator availabi]ity hypoth-

esis. ?lant Species Biology, 5i 57'64.

Kitamura, K., Shimoda, K., Nakashima, K. & Kawano, S. 1997.

Demographic genetics of the Japanese beeeh, Ftrgus crenata, at

Ogawa Forest Reserve, Ibaraki, central Honshu, Japan. I.

Spatial genetic substructuring in loeal' populations. Plant

Species Biolugy, l2: 107L[35,Kitarnura, K. Tachida, H., Takenaka, K., Furubayashi, K, &

Kawano, S. 2oo5. Demographic genetics of Siebold's beech

(Fagaceae, Flrgus crenata Blurne) populations fn the Tanzawa Mountains, central Honshu, Japan. II. spatial d{flerentiation and

estimation oMmmigration rates using a stepping' stone structure,

P]ant Spocics Bio]ogy, ZO: 133 144,Klips, R,A. & Snow, A,A, l997. Delayed autonomous sellL po][L-

nation in Hthtscus laevi (Malvaceae). American Journal of'

Botany, 84/ 48'53.Kobashi, S, 1984, On tbe

[`Prob]ems

of' local plants", Ryokka-

kogi.jutsu, 10(2): 6-10 (ill Japunese),Kudo, H.,Uchivarna, M, &Kachi,N, 199g, Fiower size variation

jn Hthiscus gkiber alld HL tiliaceus in Chichijima Island, the

Bonin (Ogasawara) Istands. Ogasawara Research, 24: 2S-34.Matsuoka, K. 2004. 0mura-Wan. Nagasaki-Shinbunsya, Naga-

saki (in japanesc),Nakunishi, H, L979, Distribution and ecology of a semi man-

grove plant, HZbiscus hamabo Sieb. et Zucc. and its communjty. Acta Phytotaxonomica et Geobotanicu, 30: ]69-I70 (in Japanese with English summary).

Nakanishi, ll. I98S. Geobotanical and ecologieal studeies on

three semi-mangrove plants in Japan. japanese Journal of

Eco[ogy, 35: 85-92,

Nakanishi, H. 2000, Distribution alld ecology of semi-mangrove,

Hthiscus hamabo community in western Kyushu, Japan, Vege-

tation Sciencc, 17: 81 SS.Nakanishi, H, 2001, D{stribution and population of Hthiscus

hamabo Siebold et Zucc. In: Studies on the vegetation ot'

alluvial plajns, (ed, Thc Association to Commemoratc the

Retirement ofProC Dr. Shigetoshi Okuda) , 37 46. The Associ-

ation of Commernorate the Retiremen[ of Profi Dr. Sigetoshi

Okuda, Yokohama (in japanese with English synopsis),

Nakanishi, H. & Kawara-Kivoura, N. 2004. Reproductive bio!-

ogy of Hthiscus hamabo Siebold et Zuoc. (Ma]vaceue). Jour-

nal of Phytogeography and Taxonomy, 52/ 47-56.

NII-Electronic



The 　Soolety 　of 　▽ egetatlon 　Solenoe

28 Vegetation　Science　Vo1　24，　No　l、2007

Nlsson ，　L．A ．1988．　 The　evolution 　of 　nowers　with 　deep　 corolla

　 tube．　 Nature，334； 147−149．Noss，　R ．F ．1990．　 Indicators 恥 r　mQnltorlng 　blod〔vers 且ty．Ahler−

　 ar ¢ hical　approach ．　Conservation　Bi〔】logy，4： 355−364．Suzuki，　K ．1992．　Bumblebee　po111nators　and 　polllnatloll　ecotypes

　 Qf 　lsodon　umbrosus 　 and 　 l，　shikokianus （Lamiaceae），　 Plant

　Species　Biology，7 ： 37　47．

Suzuki，　K ．，　Dohzono ，1．，　Hiei，　K ．＆ Fukuda，　Y ，2002，　 Pollination

　 ef℃ectiveness 　 of しhree　bumblebee　 species 　 om 　 fiowers　 of 　Hosta

　 sieろoldiana 　（Liliaceae）　and 　its　relation 　to　floral　structure　and

　polLlnator　slzes．　P］ant 　sp les　Biology，17： 139．146．Tsuji，　H．2001　 Way 　and 　problems　on 　the　creatlon 　and 　restoi

’atlon

　・fvegetatl・n．　Vegetati・ n　Science　News，　5： i5−23 （in　Japa螂 e）

Tsuji，　Ii．2002．　Present　and 　fu加 re　on 　the　creatlon 　and 　restoratlon

　 of　vegetatlon ．　Vegetation　Sclence　NeNvs，6； 42−60 （亅n　Japanesc），Washitani，1 ＆ Yaharu，　T　 1996　 An 　introduction　to　conservation

　blology：血om 　gene　to　landscape．　Bull−iehibogoshuppan，　TQkyo

　（皿 Japanese），Watanabe，　M ．，　Serizawa，　S．＆ Sugawara，　T．1996、　 Can　we 　allow

　 the　 aljen 　 Picea　J’ezoensis 　 var ，　 hondoensis（Pinaceae）in　 Mt ，

　Odaigahara？　Vcgじtation　Science，13；　IO7−llO　Gn　Jupanese），

Yoshida，　H ．

，　 Shirakihara，

　K “Shirakihara、　M ．＆ Takemur 乱，　 A ，

　 1995、　Geographic　 vanaUon 　ln　the　skull 　morphology 　of 　tho

　 finless　porPolse　1＞leophocaena　phocaenoides　in　Japanese　waters ．

　 Fisherles　Science，61−555 −558、

韈要約

　ハマボウの地域的変異と個体群多様性，中西弘樹（長

崎大学教育学部）・中西こずえ（長崎大学環境科学部）・

高木麻美（マリン技研）

　ハマボウはアオイ科の落葉低木で，関東地方南部以

西の本州，四国，九州と韓国済州島に分布し，河口付

近や入り江などの塩湿地やその周辺に生育し，純群落

を形成する，近年は河川改修や埋め立てなどによって

生育地が少なくなり，個体群が孤立化したり，群落が

縮小化している．本研究はハマボウの花と果実の形質

を調べ，個体群多様性の重要性を明らかにする目的で

行ったものである．調査は長崎県の西彼杵半島の東側

に位置する大村湾沿岸の 5つの個体群と，外海側に位

置する半島の西側の 4 つの個体群を対象に行った．各

個体群から 5 つの個体をランダムに選び，計 45個体に

っいて，各個体から 30ずっの花と果実を採集し，形質

を調べ，比較した，測定した形質は，花弁長，花弁幅，

花柱長，葯一柱頭距離葯

一葯距離雄蕊数，果実長，

果実径，1果実あたりの潜在的な種子数（胚珠数）であ

る．その結果，同一個体群内において各個体はそれぞ

れ特徴的な形質をもっているが，形質によっては差が

ないものもあった．しかし，個体群間ではすべての形

質において差が認められた．大村湾側個体群と外海側

個体群とを比較すると，大村湾側個体群の方が，花弁

長，花弁幅，葯一葯距離果実長，果実径，】果実あた

りの潜在的な種子数において値が小さかったが，葯

一

柱頭距離は値が大きかった．また，花柱長と雄蕊数は

有意な差はなかった，大村湾は超閉鎖性の湾で、約

7000年前に湖と海とが繋がり，海水が流入して成立し

たもので，海水が外海から流入した際に

，湾外のハマ

ボウが侵入し，大村湾側に拡がっていったものと考え

られ，現在は隔離状態にある．大村湾側の個体群の形

質の特徴は，ポリネーターが豊富な環境の下で，白花

受粉をさけるように進化した可能性を示している，ハ

マボウ群落の保全や植生復元には，個体群レベルで考

慮する必要があると考えられる，

N 工工一Eleotronlo 　Llbrary 　

i.gi･s local populationdiversity (malvaceae)

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