台灣柯及柳葉柯(殼斗科)之親緣地理及保育研究(I)

行政院國家科學委員會補助專題研究計畫成果報告

※※※※※※※※※※※※※※※※※※※※※※※※※

台灣柯及柳葉柯(殼斗柯)之親緣地理及保育研究 ※

※

Phylogeogr aphy and conser vation of pasania

※

formosanus and P. dodoniifolius (Fagaceae)

※※※※※※※※※※※※※※※※※※※※※※※※

計畫類別：▓個別型計畫 □整合型計畫 計畫編號：NSC90-2313-B-006-003

執行期間：90 年 08 月 01 日至 91 年 07 月 31 日

計畫主持人：蔣鎮宇 共同主持人：

計畫參與人員：

本成果報告包括以下應繳交之附件：

□赴國外出差或研習心得報告一份

□赴大陸地區出差或研習心得報告一份

□出席國際學術會議心得報告及發表之論文各一份

□國際合作研究計畫國外研究報告書一份

執行單位：國立成功大學生物系

中 華 民 國 91 年 05 月 17 日

行政院國家科學委員會專題研究計畫成果報告

台灣柯及柳葉柯(殼斗柯)之親緣地理及保育研究

Phylogeogr aphy and conser vation of Pasania formosanus and P. dodoniifolius (Fagaceae)

計畫編號：NSC 90-2313-B-006-003

執行期限：90 年 08 月 01 日至 91 年 07 月 31 日 主持人：蔣鎮宇

執行機構及單位名稱:國立成功大學生物系

一、中文摘要

本研究利用核 DNA elongation 1α intron 重建台灣柯以及柳葉柯的親緣關 係，結果顯示不論在種間以及族群間皆具 有較高的遺傳歧異度，台灣柯與柳葉柯其 種間具高的遺傳分化程度，但是在柳葉柯 族群間卻呈現較低的分化程度，此一結果 與所重建的親源樹狀圖中的結果一致，在 樹狀圖中台灣柯與柳葉柯各自行群聚在一 起形成單係群，而在柳葉柯的族群中，3 個族群的個體並無形成單係群，而是彼此 混雜在一起，再輔以地質證據顯示兩者的 共祖在冰河時期時避入冰河避難所，於後 冰河時期才擴散至現今分布地，由於分布 至不同的棲地使的兩者在開花時間上有所 差異，進而導致升殖隔離以及種化，因此 在核 DNA 的標誌上顯現高度分化的情形。

關鍵詞：核 DNA、台灣柯、柳葉柯避難所、

種化 Abstract

Gene genealogy of the nrDNA DNA elongation 1α intron was reconstructed to assess the phylogeographic pattern of two closely related oaks, Pasania formosanus and

P. dodoniifolius. High levels of nucleotide and

formosanus and P. dodoniifolius was

geological evidence, during the deglaciation period, common ancestral populations were possibly

forced to migrate into refugia at local peaks.

Invading and adapting to habitats of different elevations, two oaks flower with a lag interval of about half a month, which may have triggered the reproductive isolation and speciation.

Keyword: nrDNA、Pasania formosanus、

P. dodoniifolius、 refugia、speciation

二、緣由與目的

One of the recent developments in plant evolutionary study is the application of phylogeography to the analysis of evolutionary events (cf. Avise, 1999).

Phylogeography uses gene genealogies, which trace phylogenetic relationships among alleles within or among species, in a geographical context (Schaal, 2000). In the past years, phylogeographic patterns of many taxa that evolved through glacial cycles or vicariance events have been well

demonstrated based on genealogical

information of organelle DNA [e.g., Pinus, Latta & Mitton, 1997; Abies, Tsumura &

Suyama, 1998; and Cycas, Chiang & Peng, 1998]]; Fagus, Demesure et al., 1996,

Quercus, Petit et al., 1997; Alnus, King &

Ferris, 1998; and Beta, Desplanque et al., 2000].

High levels of genetic variation was usually detected in these species, in part due to their long evolutionary history . However, the distribution of genetic diversity varies widely between plant species. In contrast to the distinctness between species descending

from remote common ancestors (e.g., species of Sects. Lobatae and Cerris of Quercus, Manos et al., 1999), low genetic

differentiation of organelle DNAs between closely related species has been frequently encountered (e.g., Ipomopsis, Wolf et al., 1997; Quercus, Dumolin-Lapègue et al., 1999; Abies, Tsumura & Suyama, 1998).

Lineage sorting, as a result of a short period for coalescence (Futyuma, 1998), contributed to the low level of differentiation.

Nevertheless, The investigation showed that monophyly of organelle DNA haplotypes was attained in some recently evolving species.

For instance, cpDNA of Quercus tomentella (sect. Protobalanus) was proved

monophyletic, while its most related

con-sectional species Q. cedrosensis, as well as most other species, remained paraphyletic (cf. Manos et al., 1999). Processes such as fluctuation in population size, gene migration, and selection affect the genealogical

relationships among alleles (Schaal, 2000). In general, coalescence of neutral alleles (such as noncoding spacers) of maternally inherited organelle DNAs (Rebound & Zeyl, 1994) is regulated by duration of isolation, population number and size, and other evolutionary agents, such as migration (cf. Hoelzer et al., 1998).

To understand phylogeographic patterns and the gene genealogy of species of

continental islands, oaks provide ideal material. Not only because that a great number of data are available for species of continents of Europe and North America (Whittmore & Schaal, 1991; Manos et al., 1999), and the congeners share similar breeding systems and demography. In Taiwan, Lithoarpus species are highly diverged. Like many endemic species that survived glacial cycles on the island, a large number of relic oak species are sporadically distributed with limited population size, partly due to bio-geographic history and recent human disturbance (Lin, 1966). The taxonomy of Taiwan’s oaks has been well documented (Liao, 1996). Some species complexes have long puzzled taxonomists, including Pasania forPasania formosanus Skan and P. dodoniifolius Hayata. Kudo

(1931) recognized the latter as a form of P.

formosanus, and Li (1953) suggested a

Morphologically, trees of 4-9 m in height of both taxa shared entire and revolute leaf margins, obtuse leaf apex, and nuts encrusted with cupule at bottom. A single extant population of P. formosanus, with no more than 100 constituting plants, is

remained in the wild, although several scattered populations were previously recorded (cf. Lu, 1996). The population is distributed along the Nanjen Stream in the Kengting National Park. Two subpopulations occurring along ridges about 400 m alt. are separated by a stream. Only the ob-lanceolate leaf shape of P. dodoniifolius is distinct from the oblong to obovate leaf shape of P.

formosanus. In contrast the P. formosanus ,

1,200 m alt.) with about 100 individuals, Chingshuiying (ca. 1,500 m alt.) with about 200 individuals and Dazen (ca. 600 m alt.) with about 9 individuals. Two species are about 30 km apart geographically.

Populations of P. dodoniifolius are also isolated with distance between 20 km and 60 km. Ecologically, plants of both species usually grow on wind-facing slopes, mixing with other fagaceous and lauraceous species in tropical or subtropical forests. Pollen dispersal is wind-mediated, while seeds are usually carried by small mammals, such as squirrel (Chiang & Hong, 1999).

In order to determine the level of ongoing gene flow between populations, which are mostly amplified from the nrDNA DNA elongation 1α intron, were utilized to assess the extent of migration.

三、結果與討論

. A neighbor-joining (NJ) tree was

among aligned sequences of the nrDNA. All individuals of P. formosanus were grouped together, as were those of P. dodoniifolius.

Individuals of the Dazen population as well as the Weiliaoshan population were clustered together, both of which were nested within the group of the Chingshuiying population.

The neighbor-joining (NJ) tree based on the TFPGA analysis, which recognized each population (instead of individual) as a unit, suggested significant differentiation, with about 54.8 % dissimilarity between P.

formosanus and P. dodoniifolius. In addition,

Nm (1.06) and Fst (0.19149), the

subpopulations of P. formosanus were barely differentiated.

nrDNA revealed significant

differentiation between P. formosanus and P.

dodoniifolius based on the NJ tree and

Evidently, given limited pollen dispersal among populations (indicated by nrDNA), migration of oaks’ seeds across a geographic range of 20- 95 km in modern habitats is even more improbable due to the discontinuity of vegetation and the constraint of migratory capabilities of the seed-carrying animals. Although some low levels of incidental seed dispersal among populations can not be simply ruled out, unusually high

Nm values are likely to represent historical

Accordingly, gene flow between P.

dodoniifolius and P. formosanus may have

been blocked since the postglacial

resettlement. Adapting to habitats of different elevations, the two oaks flower with a lag interval of about half a month. The

reproductive barriers between the two species may be complete. Unlike European and

American oaks (Whittmore and Schaal, 1991;

Howard et al., 1997; Manos et al., 1999;

Samuel, 1999), which hybridize naturally when populations are sympatrically distributed, no interspecific hybrids have been reported or observed in the species we studied.

五、參考文獻

Avise, J. C. 2000. Phylogeography: the history and formation of species.

Harvard University Press, Cambridge.

Chiang TY, Schaal BA (1999)

Phylogeography of North American populations of the moss species

Hylocomium splendens based on the

ribosomal DNA. Molecular Ecology, 8, 1037-1042.

Chiang TY, Schaal BA, Peng CI (1998) Universal primers for amplification and sequencing a noncoding spacer

between atpB and rbcL genes of

chloroplast DNA. Botanical Bulletin of Academia Sinica, 39, 245-250.

Doyle JJ, Doyle JL (1987) A rapid DNA isolation procedure for small quantities of fresh leaf tissue. Phytochemical

Bulletin, 19, 11-15.

Dumolin-Lapegue S, Pemonge MH, Petit RJ (1997) An enlarged set of consensus primers for the study of organelle DNA in plants. Molecular Ecology, 6,

393-397.

Dumolin-Lapegue S, Demesure B, fineschi s, Le Corre V, Petit RJ (1997)

Phylogeographic structure of the white oaks throughout the European

continent. Genetics, 146, 1475-1487.

Excoffier L, Smouse PE, Quattro JM (1992) Analysis of molecular variance inferred from metric distance among DNA haplotypes: application to human

mitochondrial DNA data. Genetics, 131, 479-491.

Forcioli D, Saumitou-Laprade P, Valero M, Vernet P, Cuguen J (1998) Distribution of chloroplast DNA diversity within and among populations in

gynodioecious Beta vulgaris ssp.

maritima (Chenopodiaceae). Molecular Ecology, 7, 1183-1204.

Higgins DG, Bleasby AJ, Fuchs R (1992) CLUSTAL V: improved software for multiple sequence alignment. CABIOS, 8, 189-191.

Isagi Y, Suhandono S (1997) PCR primers amplifying microsatellite loci of

Quercu myrsinifolia Blume and their

Molecular Ecology, 6, 897-899.

King RA, Ferris C (1998) Chloroplast DNA phylogeography of Alnus glutinosa (L.) Gaertn. Molecular Ecology, 7,

1151-1161.

Kudo Y (1931) Materials for a flora of Forsomsa. VI Joumal of Society of

Tropical Agriculture, 2, 386-391.

Le Corre v, Dumolin-Lapegue S, Kremer A (1997) Genetic variation at allozyme and RAPD loci in sessile oak Quercus petraea (Matt.) Liebl.: the role of history and geography. Molecular

Ecology, 6, 519-529.

Li Hl (1953) Taxonomic notes on the Fagaceae of Formosa. Bulletin of Torrey Club, 80, 317-324.

Liao JC (1996) Fagaceae. Pp. 51-123. In Editorial Committee of the Flora of Taiwan:Flora of Taiwan, Vol. II, 2nd Edn. Editorial Committee of the Flora of Taiwan, Taipei.

McCauley DE (1995) The use of chloroplast DNA polymorphism in studies of gene flow in plants. Trends in Ecology and

Evolution, 10, 198-202.

Petit RJ, Pineau E, Demesure B, Bacilieri R, Ducousso A, Kremer A (1997)

Chloroplast DNA footprints of postglacial recolonization by oaks.

Proceedings DNA footprints of postglacial recolonization by oaks.

Sanger F, Nicklen S, Coulson AR (1977) DNA sequencing with

chain-terminating inhobitors.

Proceedings of National Academia Sciences, USA, 74, 5463-5467.

Swofford DL (1993) PAUP: Phylogenetic Analysis Using Parsimony, Version 3.1.1. Computer program distributed by the Illinois Natural History Survey, Campaign, Illinois.

Tomaru N, Takahashi M, Tsumura Y, Takahashi M, Ohba K (1998) Intraspecific variation and

phylogeographic patterns of Fagus

crenata (Fagaceae) mitochondrial DNA.

American Journal of Botany, 85,

Whittemore AT, Schaal BA (1991) Interspecific gene flow in sympatric oaks. Proceedings of National

Academia of Sciences, USA, 88,

6

附件：封面格式

行政院國家科學委員會補助專題研究計畫成果報告

※※※※※※※※※※※※※※※※※※※※※※※※※※

※ ※

※ （計畫名稱） ※

※ ※

※※※※※※※※※※※※※※※※※※※※※※※※※※

計畫類別：□個別型計畫 □整合型計畫 計畫編號：NSC － － － － －

執行期間： 年 月 日至 年 月 日

計畫主持人：

共同主持人：

計畫參與人員：

本成果報告包括以下應繳交之附件：

□赴國外出差或研習心得報告一份

□赴大陸地區出差或研習心得報告一份

□出席國際學術會議心得報告及發表之論文各一份

□國際合作研究計畫國外研究報告書一份

執行單位：

中 華 民 國 年 月 日