Abstract
Genetic divergence between population samples ofOrchis laxiflora and ofO. palustris from various European locations was studied by electrophoretic analysis of 25 enzyme loci. An average genetic distance of DNei = 1.24 was found between the two taxa, with 12 out of 25 loci showing alternative alleles (diagnostic loci). Genetic heterogeneity was observed within bothO. laxiflora andO. palustris, when northern and southeastern populations were compared, being lower in the former taxon (D = 0.06), than in the latter (D = 0.16). Karyologically, 2n = 36 was found for bothO. laxiflora andO. palustris. O. laxiflora andO. palustris produce hybrids, described asO. ×intermedia. Genotype analysis of several sympatric samples showed the presence of hybrid zones, including F1 hybrids and, in low proportions, recombinant classes, putatively assigned to Fn and backcrosses, as well as a few introgressed individuals of both taxa. These data indicate that hybrids are only partially fertile, with a very limited mixing up of the two parental gene pools; this is also shown by the lack of significant lowering of genetic distances when sympatric and allopatric heterospecific samples are compared. Accordingly,O. laxiflora andO. palustris form a syngameon; nevertheless they can be considered as good taxonomic species, with virtually distinct gene pools, which evolve independently. The genetic variability inO. laxiflora andO. palustris is remarkably low (\(\bar H\) e = 0.05 and\(\bar H\) e = 0.02, respectively). In particular, nearly complete absence of polymorphic loci was found inO. palustris from northcentral Europe. Two hypotheses are considered to explain the low genetic variability of this endangered species.
Similar content being viewed by others
References
Arduino, P., Cianchi, R., Rossi, W., Corrias, B., Bullini, L., 1995: Genetic variation inOrchis papilionacea (Orchidaceae) from Central Mediterrancean region: taxonomic inferences at the intraspecific level. — Pl. Syst. Evol.194: 9–23.
Baumann, H., Künkele, S., 1992: Die wildwachsenden Orchideen Europas. — Stuttgart: Kosmos.
—, 1988: Die Orchideen Europas. — Stuttgart: Kosmos.
Bianco, P., Medagli, P., D'Emerico, S., Ruggiero, L., 1987: Numeri cromosomici per la Flora italiana: 1139–1155. — Inform. Bot. Ital.19: 322–332.
Brewer, G. J., Sing, C. F., 1970: An introduction to isozyme techniques. — New York, London: Academic Press.
Buttler, K. P., 1986: Orchideen. Die wildwachsenden Arten und Unterarten Europas, Vorderasiens und Nordafrikas. — München: Mosaik.
—, 1979: Morphologische und geographische Differenzierung beiOrchis palustris. — Bot. Jahrb. Syst.101: 91–134.
Camus, E. G., Camus, A., 1929: Iconographie des orchidées d'Europe et du bassin mediterranéen. — Paris.
Capineri, R., Rossi, W., 1988: Numeri cromosomici per la Flora italiana: 1127–1135. — Inform. Bot. Ital.19: 314–318.
Cheliak, W. M., Pitel, J. A., 1984: Techniques for starch gel electrophoresis of enzymes from forest tree species. — Inf. Rep. Pl-X-42, Petawawa Natl. Forestry Inst., Canadian Forestry Service.
Corrias, B., Rossi, W., Arduino, P., Cianchi, R., Bullini, L., 1991:Orchis longicornu Poiret in Sardinia: genetic, morphological and chorological data. — Webbia45: 71–101.
Crow, J. F., Aoki, K., 1984: Group selection for a polygenic behavioral trait: estimating the degree of population subdivision. — Proc. Natl. Acad. Sci. USA81: 6073–6077.
Del Prete, C., 1978: Contributi alla conoscenza delleOrchidaceae di Italia. — Inform. Bot. Ital.10: 379–389.
D'Emerico, S., Bianco, P., Medagli, P., Ruggiero, L., 1990: Karyological studies of some taxa of the generaHimantoglossum, Orchis, Serapias andSpiranthes (Orchidaceae) from Apulia (Italy). — Caryologia43: 267–276.
—, 1993: Cytological and karyological studies onOrchidaceae. — Caryologia46: 309–319.
Grant, V., 1957: The plant species in theory and practice. — InMayr, E., (Ed): The species problem, pp. 39–80. — Washington, D.C.: Amer. Assoc. Adv. Sci. Publ.50.
Hamrick, J. L., Godt, M. J. W., 1990: Allozyme diversity in plant species. — InBrown, A. D. H., Clegg, M. T., Kahler, A. L., Weir, B. S., (Eds): Plant population genetics, breeding and genetic resources, pp. 43–63. — London, New York: Sinauer.
Harris, H., 1966: Enzymes polymorphism in man. — Proc. Roy. Soc. London, Ser. B., Biol. Sci.164: 298–310.
Hewitt, G., 1996: Some genetic consequences of ice ages, and their role in divergence and speciation. — Biol. J. Linn. Soc.56: (in press).
Högström, S., 1991:Orchis palustris, its history and present status on Gotland, Sweden. — Svensk Bot. Tidskr.85: 355–376.
Keller, G., Soò, R., von, 1932: Monographie und Iconographie der Orchideen Europas und des Mittelmeergebietes 2. — Berlin, Dahlem.
Koehn, R. K., Eanes, W. F., 1978: Molecular structure and protein variation within and among populations. — Evol. Biol.11: 39–100.
Liverani, P., 1992: Orchidee-specie spontanee. — Edisar.
Lönn, M., Prentice, H. C., Tegelström, H., 1995: Genetic differentiation inHippocrepis emerus (Leguminosae): allozyme and DNA fingerprint variation in disjunct Scandinavian populations. — Molec. Ecol.4: 39–48.
Nei, M., 1972: Genetic distance between populations. — Amer. Naturalist106: 283–292.
—, 1973: Analysis of gene diversity in subdivided populations. — Proc. Natl. Acad. Sci. USA70: 3321–3323.
—, 1977: F-statistics and analysis of gene diversity in subdivided populations. — Ann. Hum. Genet.41: 225–233.
—, 1987: Molecular evolutionary genetics. — New York: Columbia University Press.
Rogers, J. S., 1972: Measures of genetic similarity and genetic distance. — Studies in Genetics VII, Univ. Texas Publ. (Austin)7213: 145–153.
Romano, S., Campo, G., 1995: Numeri cromosomici per la flora italiana: 1336–1340. — Inform. Bot. Ital.27: 17–20.
Rossi, W., Corrias, B., Arduino, P., Cianchi, R., Bullini, L., 1992a: Gene variation and gene flow inOrchis morio (Orchidaceae) from Italy. — Pl. Syst. Evol.179: 43–58.
—, 1992b: A new natural hybrid in the genusOrchis L.: genetic data and description. — Lindleyana7: 121–126.
Sarich, V., 1977: Rates, sample sizes and the neutrality hypothesis for electrophoresis in evolutionary studies. — Nature265: 24–28.
Scacchi, R., De Angelis, G., 1989: Isoenzyme polymorphism inGymnadenia conopsea and its inferences for systematics within this species. — Biochem. Syst. Ecol.17: 25–33.
—, 1990: Allozyme variation among and within elevenOrchis species (fam.Orchidaceae), with special reference to hybridizing aptitude. — Genetica81: 143–150.
—, 1991: Effect of the breeding system on the genetic structure in threeCephalantera spp. (Orchidaceae). — Pl. Syst. Evol.176: 53–61.
Schlechter, R., 1928: Monographie und Iconographie der Orchideen Europas und des Mittelmeergebietes 1. — Berlin, Dahlem.
Schlegel, M., Steinbrück, G., Hahn, K., Röttger, B., 1989: Interspecific relationships of ten European orchid species as revealed by enzyme electrophoresis. — Pl. Syst. Evol.163: 107–119.
Scrugli, A., 1977: Numeri cromosomici per la Flora Italiana. — Inform. Bot. Ital.14: 275–279.
—, 1981: Sul numero cromosomico diOrchis laxiflora Lam. — Inform. Bot. Ital.13: 119–121.
Selander, R. K., Smith, M. H., Yang, S. Y., Johnson, W. E., Gentry, J. B., 1971: Biochemical polymorphism and systematics in the genusPeromyscus. I. Variation of the oldfield mouse (Peromyscus polionotus). — Studies in Genetics VI, Univ. Texas Publ. (Austin)7103: 49–90.
Slatkin, M., Barton, N. H., 1989: A comparison of three indirect methods for estimating average levels of gene flow. — Evolution43: 1349–1368.
Sokal, R. R., Rohlf, F. J., 1981: Biometry. 2nd edn. — San Francisco: Freeman.
Soltis, D. E., Haufler, C. H., Darrow, D. C., Gastony, G. J., 1983: Starch gel electrophoresis of ferns: a compilation of grinding buffers, gel and electrode buffers and staining schedules. — Amer. Fern J.73: 9–27.
Soó, R. von, 1980:Dactylorhiza, Orchis. — InTutin, T. G., Heywood, V. H., Burges, N. A., Valentine, D. H., Walters, S. M., Webb, D. A., (Eds): Flora Europaea5, pp. 341–342. — Cambridge: Cambridge University Press.
Steinbrück, G., Schlegel, M., Dahlström, I., Röttger, B., 1986: Characterization of interspecific hybrids betweenOrchis mascula andO. pallens (Orchidaceae) by enzyme electrophoresis. — Pl. Syst. Evol.153: 229–241.
Vermeulen, P., 1947: Studies on Dactylorchids. — Utrecht.
—, 1949: Varieties and forms of Dutch orchids. — Ned. Kruidk. Arch.56: 204–242.
Wilkinson, L., Leland, J., 1989: SYSTAT: the system for statistics. — Evanston, Illinois: SYSTAT Inc.
Workman, P. L., Niswander, J. D., 1970: Population studies on southwestern Indian tribes. II. Local genetic differentiation in the Papago. — Amer. J. Hum. Genet.22: 24–49.
Wright, S., 1931: Evolution in Mendelian populations. — Genetics16: 97–159.
—, 1943: Isolation by distance. — Genetics28: 114–138.
—, 1951: The genetical structure of populations. — Ann. Eugen.15: 323–354.
—, 1978: Evolution and the genetics of populations. 4. Variability within and among natural populations. — Chicago: University of Chicago Press.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Arduino, P., Verra, F., Cianchi, R. et al. Genetic variation and natural hybridization betweenOrchis laxiflora andOrchis palustris (Orchidaceae). Pl Syst Evol 202, 87–109 (1996). https://doi.org/10.1007/BF00985819
Received:
Revised:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00985819