The importance of clonal growth in woody plants − insights from molecular genetics.
Douhovnikoff, Vladimir*,1, 1 Simmons College, Boston, MA
ABSTRACT- Despite the potential importance of clonal growth in woody plants surprisingly few clonal studies have focused on trees. In fact, most research involving woody plant population dynamics has focused exclusively on sexual reproduction. This is reflected in the emphasis such reproduction is given in most ecological and evolutionary theories and models. Yet, in many species the persistence of existing plant genotypes through clonal spread can be the more important avenue to plant population regeneration and maintenance. One explanation for the limited consideration given to clonal growth in woody plant systems is the historic difficulty in identifying clonal members. Until the recent development of molecular methods, ecologists were limited to identifying clones by root connectivity and by similarities in plant phenology and morphology. However, excavation, to expose roots, is not effective over large areas due to the high cost, root fragmentation, and root grafting. Phenological and morphological similarities are difficult to test for accuracy, are unreliable due to plasticity, and require many hours of on-site observations over an extended period of time. Molecular genetic methods, on the other hand, allow for identification of clones independent of environmental variation, can be easily tested for accuracy and reproducibility, and can give results after a single collection of vegetative material from the field. The advent of these new technologies now permits a revisiting of established theory and where appropriate the inclusion of clonal growth as a contributing factor. Studies of clonal growth in sandbar willow (Salix exigua) and coast redwood (Sequoia sempervirens) offer specific examples in disparate species. −−
Key words: clonal growth, molecular ecology, Salix
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