Impact of hydraulic architecture on tree performance

Tyree博士开发了定量模型，预测树木的水力传导率如何影响光合作用过程，从而影响树木的生长速度。但是，需要做更多的发现为导向的研究，以验证和提高模型的预测能力。有越来越多的证据表明，水分在土壤和根，茎和树叶的传输效率（水力传导）设置限制树木的性能：蒸腾，碳增益和树木的生长速度。此外，有证据表明，干旱事件和冻融循环对水的运输效率产生了强烈的负面影响，从而影响了树木的生产力和生存。最近，人们已经清楚，植物有动态控制根和叶的水力传导，通过基因表达的水通道蛋白，这是蛋白质，驻留在细胞膜上，并加强水在trees.The研究计划的目的，在这个NSERC发现格兰特是批判性地分析加拿大最广泛的树木，杨树，白杨和三角叶杨的水力结构。这些研究将调查水分运输的根和芽组成部分，包括木质部结构和功能以及水通道蛋白，特别强调对干旱和寒冷的适应性。这些水关系的特点将与正在进行的研究正在调查的热带树木。这项研究将揭示树木生态生理学和适应冷温带气候的基本方面，并解决更广泛的问题，“树木如何独特地适应不同的生物物理生态区？”'.第二个目的是将获得的知识基础转移到可持续林业做法和农林业的潜在商业开发中

Dr. Tyree has developed quantitative models that predict how hydraulic conductivity of trees impacts the photosynthetic process and hence the rate of tree growth. But more discovery oriented research needs to be done to validate and improve the predictive capacity of the model.There is increasing evidence that the efficiency of water transport (hydraulic conductance) in soils and in roots, stems and leaves of trees sets limits on tree performance: transpiration, carbon gain and growth-rate of trees. Furthermore, there is evidence of a strong negative-impact of drought events and freeze-thaw cycles on the efficiency of water transport and hence tree productivity and survival. More recently, it has become clear that plants have dynamic control over root and leaf hydraulic conductance through gene expression for aquaporins, which are proteins that reside in cell membranes and which enhance water transport in trees.The purpose of the research program in this NSERC Discovery Grant is to critically analyze hydraulic architecture of Canada's most widespread trees, poplars, aspens and cottonwoods. The studies will investigate root and shoot components of water transport, including xylem structure and function and aquaporins, with particular emphasis on prospective adaptations to drought and cold. These water relations characteristics will be compared with those of tropical trees that are being investigated in ongoing studies. The research will reveal fundamental aspects of tree ecophysiology and adaptation to cold-temperate climates, and address the broader question, 'how are trees uniquely adapted to different biophysical ecoregions?'.A secondary intent is to transfer the knowledge base gained to potential commercial exploitation in sustainable forestry practices and agro-forestry