Molecular and dendrochronological analysis of natural root grafting in Populus tremuloides (Salicaceae)

Trembling aspen (Populus tremuloides) is a clonal tree species, which regenerates mostly through root suckering. In spite of vegetative propagation, aspen maintains high levels of clonal diversity. We hypothesized that the maintenance of clonal diversity in this species can be facilitated by integra...

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Bibliographic Details
Published in:	American journal of botany 2009-08, Vol.96 (8), p.1500-1505
Main Authors:	Jelínková, Hana, Tremblay, Francine, DesRochers, Annie
Format:	Article
Language:	eng
Subjects:	aspen Biodiversity Botany clonal integration dendrochronology diversity Ecological genetics Excavations Genetics Genotype & phenotype Genotypes microsatellites Molecular biology natural root grafting Plant genetics Plant roots Populus tremuloides root system Root systems Salicaceae Species diversity Stems Tissue grafting Trees Vegetation
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Summary:	Trembling aspen (Populus tremuloides) is a clonal tree species, which regenerates mostly through root suckering. In spite of vegetative propagation, aspen maintains high levels of clonal diversity. We hypothesized that the maintenance of clonal diversity in this species can be facilitated by integrating different clones through natural root grafts into aspen's communal root system. To verify this hypothesis, we analyzed root systems of three pure aspen stands where clones had been delineated with the help of molecular markers. Grafting between roots was frequent regardless of their genotypes. Root system excavations revealed that many roots were still living below trees that had been dead for several years. Some of these roots had no root connections other than grafts to living ramets of different clones. The uncovered root systems did not include any unique genotypes that would not occur among stems. Nevertheless, acquiring roots of dead trees helps to maintain extensive root systems, which increases the chances of clone survival. Substantial interconnectivity within clones as well as between clones via interclonal grafts results in formation of large genetically diverse physiological units. Such a clonal structure can significantly affect interpretations of diverse ecophysiological processes in forests of trembling aspen.
ISSN:	0002-9122 1537-2197