Diversity and Adaptive Physiology of Riparian Cottonwoods and Hybrid Poplars

杨树为北半球周围的一系列森林提供了基础。它们是加拿大最丰富和分布最广的树木，艾伯塔省南部提供了全球杨树生物多样性中心，因为五种树种重叠，四种棉杨或河谷杨树杂交。棉杨还为人工杂交杨树提供亲本物种，这是加拿大和其他温带地区生长最快的树木。不幸的是，河岸的白杨林一直在倒塌，这主要是由于河流筑坝和为灌溉和其他人类用途而取水。 在这个研究项目中，我将调查北美棉杨的生理多样性和适应性。阿尔伯塔省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。我们还在研究从艾伯塔省到亚利桑那州的整个纬度范围内的狭叶棉杨。与大多数植物不同，杨树不是雄性就是雌性，我们将调查性别差异及其原因。我们的研究调查生理，形式和功能的混合，我们将比较和对比棉杨种类和他们的杂交。我们将研究生长发育，并分析光合作用、碳捕获和蒸腾水分利用。我们将调查对干旱和洪水的反应，并试图了解这些物种如何适应不同的环境，例如从山脉到草原的河谷环境。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特征之间的联系。这些重要和新颖的调查将有助于保护和恢复我们的泛滥平原森林所需的知识，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。这项研究还将确定可遗传的生理特性，使未来的杂交杨树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.