Impact of hydraulic architecture on tree performance

泰里博士开发了定量模型，预测树木的水力传导性如何影响光合作用过程，从而影响树木的生长速度。但需要进行更多以发现为导向的研究，以验证和改进该模型的预测能力。越来越多的证据表明，土壤以及树木根、茎和叶中水分运输(水力传导性)的效率限制了树木的表现：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运输的效率产生了强烈的负面影响，从而影响了树木的生产力和存活率。最近，植物通过水通道蛋白的基因表达对根和叶的水力传导性进行动态控制变得明显起来。水通道蛋白是一种驻留在细胞膜中的蛋白质，可以增强树木的水分运输。这项NSERC发现基金的研究计划的目的是批判性地分析加拿大分布最广的树木、杨树、杨树和棉白杨的水力结构。这些研究将研究水分运输的根和地上部成分，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预期适应。这些水分关系特征将与正在进行的研究中正在调查的热带树木的特征进行比较。这项研究将揭示树木生态生理和对寒温带气候适应的基本方面，并解决更广泛的问题，即树木如何独特地适应不同的生物物理生态区？第二个目的是将所获得的知识基础转移到可持续林业实践和农林复合中潜在的商业开发

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