Morphological dissection of leaf, bud and infructescence traits of the interfertile native A. glutinosa and non-native A. incana in Flanders (northern part of Belgium)
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Spontaneous hybrids in natural regenerations of A. glutinosa cannot be excluded if A. incana is occurring in the neighbourhood, and has to be taken into account when restoring swamp forests.
Swamp forests with A. glutinosa are endangered in Flanders due to habitat destruction and fragmentation, and therefore restoration is promoted. At the other hand, frequent plantations of A. incana, a non-native species in Flanders (northern part of Belgium), may facilitate spontaneous hybrids between the two species as they are interfertile. We assessed phenotypic variability of both species and putative hybrids using nine leaf, five infructescence and eight bud characters, and additionally height growth. We focussed on a field trial established with seeds collected in fifteen autochthonous A. glutinosa stands and on A. incana trees of unknown origin sampled at five locations in Flanders. We applied geometric morphometric methods, principal component analyses and mixed modelling methods. We found three individuals with intermediate morphological traits between A. glutinosa and A. incana among the eleven pedigrees in one of the two natural A. glutinosa populations where also planted A. incana was present. Their height growth was variable and only one of the three fructified, with seeds showing a normal germination success. These individuals can be hybrids with intermediate features between the parental species or they may display the natural variability of the latter with overlapping traits. Other individuals with intermediate leaf shape but less intermediate features for other leaf, bud and infructescence characters, found in the pedigrees of additional four A. glutinosa populations, may point to the relative wide natural variability for leaf shape within the parental species. Alternatively, these may concern backcrossed individuals or matro/patroclinal inheritance in hybrids. An inter-population variance study showed that several leaf characters are under a relative genetic control, underlining the importance of vegetative organs in taxonomic treatment of species complexes. The occurrence of spontaneous hybrids in natural regenerations of A. glutinosa cannot be excluded if A. incana is present in the neighbourhood, and has to be taken into account both in seed collections for the creation of autochthonous planting stock as when restoring swamp forests.
KeywordsAlder Geometric morphometrics Hybridisation Principal components analysis Plant morphology Variance structure
We thank David De Lignie, Stefaan Moreels, Wim Stevens, Steven Haelterman, Yves Verhaegen, André Meersman and Karen Cox, all affiliated to the Research Institute for Nature and Forest, for seed collections, plant growth, planting of the field trial and plantation management. Furthermore we specifically thank Jaennine Moeskops, a volunteer, for several morphological measurements and observations on the herbarium.
Conflict of interest
The author declares that she has no conflict of interest.
- Banaev EV, Bazant V (2007) Study of natural hybridisation between Alnus incana (L.) Moench. and Alnus glutinosa (L.) Gaertn. J Forest Sci 53:66–73Google Scholar
- Bates D, Maechler M, Bolker B, Walker S (2014) lme4: linear mixed-effects models using Eigen and S4. R package version 1.1-7. http://CRAN.R-project.org/package=lme4
- Hegi G (1981) Illustrierte Flora von Mitteleuropa. Band III/1. Paul Parey, BerlinGoogle Scholar
- Lambinon J, De Langhe J, Delvosalle L, Duvigneaud J (1998) Flora van België, het Groothertogdom Luxemburg, Noord-Frankrijk en de aangrenzende gebieden. Nationale Plantentuin, MeiseGoogle Scholar
- Mejnartowicz L (1999) Evidence for long-term heterosis phenomenon in the Alnus incana × glutinosa F-1 hybrids. Silvae Genet 48:100–103Google Scholar
- Paelinckx D, Sannen K, Goethals V, Louette G, Rutten J, Hoffmann M (2009) Gewestelijke doelstellingen voor de habitats en soorten van de Europese Habitaten Vogelrichtlijn voor Vlaanderen. Mededelingen van het Instituut voor Natuur-en Bosonderzoek INBO.M.2009.6, BrusselsGoogle Scholar
- Poljak I, Idzojtic M, Sapic I, Vukelic J, Zebec M (2014) Population variability of grey (Alnus incana L. Moench) and black alder (A. glutinosa L. Gaertn.) in the Mura and Drava region according to the leaf morphology. Sumar List 138:7–17Google Scholar
- Punyasena SW, Smith SY (2014) Bioinformatic and biometric methods in plant morphology. Appl Plant Sci 2Google Scholar
- R_Core_Team (2013) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna. http://www.R-project.org/
- Rohlf J (2010) tpsDig v 2.16 (computer program). Stony Brook University, New YorkGoogle Scholar
- Sheets D (2004) CoordGen6f and PCAGen6n (computer programs). Canisius College, New YorkGoogle Scholar
- Slice D (2013) Morpheus (computer program). Department of Scientific Computing, The Florida state University, FloridaGoogle Scholar
- Vander Mijnsbrugge K, Cox K, Van Slycken J (2005) Conservation approaches for autochthonous woody plants in Flanders. Silvae Genet 54:197–206Google Scholar
- Viscosi V, Cardini A (2011) Leaf morphology, taxonomy and geometric morphometrics: a simplified protocol for beginners. PLoS ONE 6Google Scholar
- Vit P, Lepsi M, Lepsi P (2012) There is no diploid apomict among Czech Sorbus species: a biosystematic revision of S. eximia and discovery of S. barrandienica. Preslia 84:71–96Google Scholar