Diversity and Adaptive Physiology of Riparian Cottonwoods and Hybrid Poplars

杨树，白杨树，为北方的一系列森林提供了基础。 它们是加拿大最丰富和最广泛的树木，阿尔伯塔南部提供了一个全球白杨生物多样性中心，因为五个物种重叠，四个三角叶杨，或河谷杨树杂交。 美洲黑杨还为人工杂交杨树提供了亲本物种，这是加拿大和其他温带地区生长最快的树木。 不幸的是，河岸的棉白杨森林正在崩溃，这主要是由于河流筑坝和取水用于灌溉和其他人类用途。 在这个研究项目中，我将调查整个北美三角叶杨的生理多样性和适应性。 阿尔伯塔南部的河岸森林提供了一个丰富而独特的“天然实验室”，我将把研究扩展到不列颠哥伦比亚省和萨斯喀彻温省。 我们也在研究从阿尔伯塔到亚利桑那州的窄叶棉白杨。与大多数植物不同，白杨要么是雄性要么是雌性，我们将研究性别如何不同，以及为什么。 我们的研究调查生理学，形式和功能的融合，我们将比较和对比棉白杨物种及其杂交种。我们将研究生长和发育，并分析光合作用，碳捕获和蒸腾用水。 我们将调查对干旱和洪水的反应，并试图了解物种如何适应不同的环境，例如从山区到草原的河谷。 我们还将研究特定基因的变异，并通过全基因组测序，寻找遗传标记和生理性状之间的关联。这些重要而新颖的调查将有助于保护和恢复我们的洪泛区森林所需的知识，这些森林提供丰富的野生动物栖息地，稳定河岸，并有助于水质和健康的水生生态系统。 该研究还将确定可遗传的生理特征，这些特征可能使未来的杂交白杨种植园能够在更广泛的环境中种植，并选择适合环境复垦的杨树。

Poplars, Populus trees, provide the foundations for a range of forests around the Northern Hemisphere. They are the most abundant and extensive trees in Canada, and southern Alberta provides a global centre of poplar biodiversity as five species overlap and the four cottonwoods, or river valley poplars, hybridize. Cottonwoods also provide the parental species for artificial hybrid poplars, the fastest-growing trees in Canada and other temperate regions. Unfortunately, riparian cottonwood forests have been collapsing, largely due to river damming and water withdrawal for irrigation and other human uses. In this research program, I will investigate the physiological diversity and adaptations across the North American cottonwoods. The riparian forests of southern Alberta provide a rich and unique 'natural laboratory' and I will extend studies into British Columbia and Saskatchewan. We are also studying narrowleaf cottonwoods from their full latitudinal range from Alberta to Arizona. Unlike most plants, poplar trees are either male or female and we will investigate how the sexes differ, and why. Our studies investigate physiology, the blending of form and function, and we will compare and contrast the cottonwood species and their hybrids. We will study growth and development, and analyze photosynthesis, carbon capture, and transpirational water use. We will investigate responses to drought and to flooding and seek to understand how the species are adapted to the diverse environments, such as in river valleys from the mountains to the prairies. We will also investigate variation in specific genes and through whole genome sequencing, seeking associations between genetic markers and physiological traits. These important and novel investigations will contribute to the knowledge required to conserve and restore our floodplain forests, which provide rich wildlife habitats, stabilize stream banks, and contribute to water quality and healthy aquatic ecosystems. The research will also identify heritable physiological traits that may enable future hybrid poplar plantations across a broader range of environments, and the selection of poplars suitable for environmental reclamation.