Palms: A Model System for Evaluating Hydraulic Costs of Plant Size

获奖摘要：内森·g·菲利普斯棕榈树：一个评估植物大小的水力成本的模型系统。树木高度的限制是什么？这个问题既是生物学家的根本兴趣，也是那些对林业管理和碳封存感兴趣的人的根本兴趣。这项研究将侧重于水运，这是可能限制树木高度的几个关键因素之一。树木高度的水力成本背后的物理和生物学是复杂的，因此不太清楚，因为大多数树种的分支结构将水流分成无数的流动路径。此外，复杂分支将叶子分布在多面层中，这进一步增加了复杂性。本研究的目的是通过使用柱状棕榈作为水力树结构的简单模型来简化树高水力成本的评估问题。棕榈树研究将在厄瓜多尔的蒂普蒂尼研究站进行。柱状棕榈树的结构特征可以用来分析没有树枝的树木的用水情况。棕榈树由一个单独的管道组成，该管道将水供应给独特而紧凑的叶子冠。测量将表征水流通过不同高度的手掌，直到它们的最大值。在为期三年的研究项目中，对水分限制对生长的综合影响进行建模，将澄清对六种特定机制的相对优势的理解，这些机制会产生水运成本，并可能限制树木的垂直高度生长。本研究将考察水运的基本生物物理过程，从而使该项目提高对大多数树种用水的了解。该项目包括促进厄瓜多尔和美国本科生之间的国际科学合作和交流的更广泛影响。此外，该项目为整个亚马逊地区棕榈树的经济和社会利用提供了科学依据，据估计，棕榈树的经济重要性仅次于草地。最后，该项目将继续为美国国家科学基金会在蒂普蒂尼生物多样性站的本科生教育活动和研究培训提供支持。

Award Abstract for Nathan G. Phillips Palms: A Model System for Evaluating Hydraulic Costs of Plant Size What are the limits to tree height? This question is both of fundamental interest to biologists, and to those interested in the management of forestry and carbon sequestration. This research will focus on water transport that is one of several key factors that may constrain tree height. The physics and biology underlying hydraulic costs of tree height are complex, and therefore not well understood, because the branching architecture in most tree species ramifies the water stream into innumerable flow paths. In addition, complex branching distributes foliage in multi-faceted layers adding further complexity. The goal of this research is to simplify the problem of assessing hydraulic costs of tree height by using the columnar palm as a simple model of hydraulic tree structure. The research with palms will take place at the Tiputini Research Station in Ecuador. The structural traits of the columnar palms allow analysis of water use in trees without branches. Palm trees consist of a solitary pipeline that supplies water to a distinct and compact crown of leaves. Measurements will characterize water flow through palms that vary in height, up to their maximum. Modeling of integrated impacts of water limitation on growth during the three-year research project will clarify understanding of the relative strengths of six specific mechanisms that incur costs for water transport and potentially limit vertical height growth in trees. Fundamental biophysical processes of the water transport will be examined in this research, resulting in the project improving understanding of water use by most tree species. The project includes broader impacts that promote international scientific cooperation and exchange between Ecuadorian and U.S. undergraduate students. In addition, the project provides a scientific basis for the economic and social use of the palms throughout Amazonia, which are estimated to be second only to grasses in economic importance. Finally, the project will contribute to continuing NSF support for undergraduate educational activities and research training at the Tiputini Biodiversity Station.