Tree hydraulics equipment for assessing tree drought mortality under future climate conditions

全球树木死亡率正在上升，在加拿大，由于与气候变暖相关的干旱胁迫，大片杨树林正在死亡。虽然随着气温的升高，与干旱相关的森林衰退预计将变得更加普遍，但生长温度和二氧化碳浓度的增加会改变树木的生物量分配和水分运输生理，这可能会使树木在未来更容易或更不容易受到干旱胁迫的影响。这项提议将资助一个高压流量计，用于测量未来气候情景如何改变杨树根、茎和叶的水分输送能力。杨树将在三种温度(环境温度、+4和+8摄氏度)以及当前环境或两次环境大气二氧化碳浓度(390ppm或780ppm)下在西部大学的Biotron中种植，并接受干旱处理。高压流量计将有助于快速测量植物组织中的水流阻力，使我的实验室能够确定干旱如何逐步影响适应不同生长环境的树木的水分运输。这项研究将为森林管理者预测加拿大在气候变化中的森林生长和健康提供关键问题，通过洞察干旱导致的杨树死亡在未来是否会增加严重程度。这项研究还将有助于确定哪些生理性状在一系列生长条件下提高了杨树的抗旱性，使育种者能够开发出更具抗逆性的树种，用于生物质和生物燃料，并有助于填补植物水力特性对环境可塑性的基本知识空白。这笔赠款将支持立即对一名硕士学生进行植物水关系和气候压力对加拿大森林的影响的培训，并为今后的本科生和研究生在紧迫的林业问题上的培训提供便利。这笔赠款将使我能够购买对我作为一名早期职业研究员的研究计划发展至关重要的设备，并促进尖端研究，以延续我的实验室在主要期刊上发表高质量全球变化研究的记录。

Tree mortality rates are increasing globally, and in Canada, large tracts of aspen stands are dying due to drought stress associated with climate warming. While drought-related forest decline is expected to become more common as temperatures rise, increasing growth temperatures and CO2 concentrations alter tree biomass allocation and water transport physiology, which could make trees either more or less vulnerable to drought stress in the future. This proposal will fund a high-pressure flow meter for measuring how future climate scenarios alter aspen water transport capacity in roots, stems and leaves. Aspen will be grown at each of three temperature regimes (ambient temperatures, +4 and +8 degrees Celsius) and either current ambient or twice-ambient atmospheric CO2 concentrations (390 ppm or 780 ppm) in the Biotron at Western University, and subjected to a drought treatment. The high-pressure flow meter will facilitate rapid measurements of resistance to water flow in plant tissues, allowing my lab to determine how drought progressively affects water transport in trees acclimated to different growth environments. The research will address crucial problems for forest managers in projecting Canada's forest growth and health in a changing climate by providing insight into whether drought-induced aspen mortality will increase in severity in the future. This study will also help identify which physiological traits improve aspen drought tolerance under a suite of growth conditions, allowing breeders to develop more stress resistant tree varieties for biomass and biofuel purposes, and helping fill a basic knowledge gap on the plasticity of plant hydraulic characteristics to the environment. The grant will support the immediate training of a Masters student in plant water relations and climate stress effects on Canada's forests, as well as facilitating future undergraduate and graduate student training in pressing forestry-related issues. This grant will allow me to buy equipment crucial to the development of my research program as an early career researcher and facilitate cutting-edge research to continue my lab's record of publishing high-quality global change research in premier journals.