Biology of PopulusThe genus Populus includes the poplars, cottonwoods and aspens. These deciduous trees are adapted to environments throughout the northern hemisphere, with some species ranging north of 20 degrees latitude. Trees of the genus play various ecological roles and provide benefits including quickly reestablishing stands after disturbance such as fire. As pioneer species, Populus includes some of the fastest growing trees of the temperate zone.
Click here to see distribution maps of North American Populus species
|
Aspen grove spreading into meadow near Lake Tahoe. |
Populus species are obligate outcrossers. Individual trees are highly heterozygous, and populations are typified by large genetic diversity. Asexual reproduction is common for some Populus. For example P. tremuloides (quaking aspen) grows as large clonal stands through root suckers. Hybridization is common among Populus species, and can create novel genotypes with unique ecological traits. Hybridization is also used in the production of fast growing commercial hybrids that display heterosis for key growth-related traits. |
The development of Populus genomic resources is allowing new understanding of tree growth and function at the ecological and community-levels. The recent sequencing of the Laccaria bicolor genome will further our understanding of the interaction of this fungus with Populus roots in ectomycorrhizal symbiosis. Similarly, the genome of the poplar leaf rust Melampsora laricis-populina genome has also been sequenced and should allow new understanding of pathogen-host interactions.
