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Titolo:
A GENETIC-STUDY OF FAGUS-SYLVATICA L VAR TORTUOSA PEPIN
Autore:
DEMESURE B; COMPS B; THIEBAUT B; BARRIERE G; LETOUZEY J;
Indirizzi:
UNIV BORDEAUX 1,DEPT BIOL VEGETAL LIGNEUX,ECOL GENET LAB,AVE FAC F-33405 TALENCE FRANCE UNIV BORDEAUX 1,DEPT BIOL VEGETAL LIGNEUX,ECOL GENET LAB F-33405 TALENCE FRANCE UNIV MONTPELLIER 2,INST BOT F-34000 MONTPELLIER FRANCE CNRS,CTR ECOL FONCT & EVOLUT F-34033 MONTPELLIER FRANCE
Titolo Testata:
Annales des Sciences Forestieres
fascicolo: 2, volume: 52, anno: 1995,
pagine: 103 - 115
SICI:
0003-4312(1995)52:2<103:AGOFLV>2.0.ZU;2-G
Fonte:
ISI
Lingua:
FRE
Soggetto:
SUBDIVIDED POPULATIONS; DIVERSITY;
Keywords:
WINDING BEECH; FAGUS SYLVATICA L VAR TORTUOSA PEPIN; ALLOZYME; LAYERING;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
38
Recensione:
Indirizzi per estratti:
Citazione:
B. Demesure et al., "A GENETIC-STUDY OF FAGUS-SYLVATICA L VAR TORTUOSA PEPIN", Annales des Sciences Forestieres, 52(2), 1995, pp. 103-115

Abstract

A form of the European beech (Fagus sylvatica L) was described as 'Tortillard' (var tortuosa Pepin) by Pepin (1861). We have named this form 'winding beech'. It exists at present in 3 European stands: in Verzy, near Reims (France, 49 degrees 14'N, 3 degrees 59'E, alt 288 m); in the Suntel mountains, near Hanover (Germany, 52 degrees 12'N, 9 degrees 17' E, alt 170-250 m); and in Dalby-Soderskogs in southern Sweden (55 degrees 38'N, 13 degrees 19'E). These stands are located within the optimal European range of the beech (fig 1). In each stand, common beech (F sylvatica L) and winding beech (F sylvatica L vartortuosa Pepin)coexist and, in spite of gene exchanges (surely limited) they keep their respective morphological characters and can be considered as 2 'subpopulations: A genetic analysis of the 6 subpopulations was carried out using 12 polymorphic alloenzymatic markers. We also analysed: (i) individuals from populations of other beech species, using the same markers; and (ii) individuals from common beech populations located in the 3 regions where winding beeches are found. Interstand and intrastandallelic frequencies were compared. We also carried out: (i) a hierarchical analysis including the 6 subpopulations, using Nei's genetic distances; and (ii) a discriminant analysis including the 6 subpopulations and the other sampled beech stands. We then compared (i) the heterozygote numbers of the 2 subpopulations within each stand, at each locusand for all loci together; and (ii) the homozygote and heterozygote distribution at 1, 2, 3,... 8 loci. Multilocus F(i)s values were also computed. All alloenzymes observed in common beech are present in winding beech, whereas some were not observed in other beech species (tableI). Moreover, in these other species new alloenzymes appear. Thus it is possible to suppose that both forms of the European beech still have a common evolutive history and that their separation is rather recent and even incomplete. The comparison between the allelic frequencies of the 2 subpopulations within each stand shows a very small number ofsignificant deviations (table II). On the other hand, the interstand comparison between winding beech subpopulations or between common beech subpopulations shows that most deviations are significant (table II). This result is confirmed by the dendrogram built from Nei's genetic distances (fig 2). The discriminant analysis divides the 6 subpopulations and the beech stands sampled within the 3 regions into 3 groups according to their geographical location (fig 3). There is no differenceof F(i)s values between the 2 subpopulations within each stand (fableIII). The heterozygote number at each locus (table IV) and the distribution of homozygotes (0) and heterozygotes at 1,2,3... 8 loci (table V) differ very little from one subpopulation to the other within each stand. From all these results we can discuss some previous hypotheses:(i) a geographical common origin of both beech forms and material transports from one stand to another (ii) the preponderance of vegetativereproduction in winding beech; (iii) the degeneration of winding beeches caused by endogamy, genetic drift and vegetative reproduction; and(iv) a wider and more continual former geographical area. This study questions the transport of material from I station to another and the degeneration of the winding beech and minimizes the influence of vegetative reproduction (table VI,, fig 4). it also leads to a discussion on the origin of the winding beech; our results do not provide enough arguments in favour of either a wider former geographical area or a multiple origin.

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Documento generato il 27/11/20 alle ore 12:40:44