Collaborative Research: Seeing the forest with the leaves--inferring plant habit and ecophysiology from leaf fossils

合作研究：以叶见林--从叶化石推断植物习性与生态生理凯文·博伊斯1 Maciej A Zwieniecki 2（PI）1.-芝加哥大学地球物理科学系，芝加哥，IL 60637.2。哈佛大学阿诺德植物园，剑桥，MA 02138。 由于叶是植物与环境之间的主要界面，化石叶形态已被广泛证明是有关过去气候和大气成分的有价值的信息来源。 然而，从叶子的角度来看，叶子所附着的植物与区域气候一样是其环境的一部分。 因此，化石叶也可能保存了大量尚未开发的关于原生植物的习性和生态以及景观植被结构的信息。 这个项目的主要目标是开发解剖代理解释三个参数的全植物生态生理学的叶化石使用新兴的机械理解叶结构和生理学是如何联系在一起的。 1)植物习性-高的树或低的灌木-提供了从具有相似的总脉数的叶压缩之间的脉密度的变化。 2)适应水蒸气压力赤字-一个阳光明媚，暴露的环境或阴影，林下环境-提供的比例的静脉静脉和静脉叶表面的距离解剖保存的叶化石。 3)碳同化和蒸腾能力由叶片压缩时每叶表面积的叶脉密度提供。 这些工具将通过在热带和温带森林进行一系列生物遗传学和生态学上多样化的实地测量以及温室和生长室实验来建立，以模拟现代世界不再存在的条件。 第一个应用程序将集中在白垩纪/早新生代开花植物的多样性和晚古生代种子植物的多样性的关键化石的生态生理学-关键主题本身，但也很重要的介绍这些技术到更大的古生物学社区。一个关键点是，代理是基于了解生理机制，而不仅仅是统计相关性。 因此，它们将提供给所有对植物进化的任何时期感兴趣的古生物学家，从泥盆纪的第一片叶子和森林到近代。 这些工具将有助于化石的重建和对生理学和生态学进化的理解。 更广泛地说，这项工作将提供一种新的方法来约束过去的气候以及深时的碳和水文循环。

COLLABORATIVE RESEARCH: SEEING THE FOREST WITH THE LEAVES--INFERRING PLANT HABIT AND ECOPHYSIOLOGY FROM LEAF FOSSILSC. Kevin Boyce1 & Maciej A Zwieniecki2 (PIs)1.-Department of Geophysical Sciences, University of Chicago, Chicago, IL 60637.2. Arnold Arboretum of Harvard University, Cambridge, MA 02138.Detached leaves are among the most common of plant macrofossils. Because leaves are the primary interface between plant and environment, fossil leaf morphology has been widely proven to be a valuable source of information regarding past climates and atmospheric compositions. From the leaf's perspective, however, the plant to which the leaf is attached is as much a part of its environment as regional climate. Thus, fossil leaves may also preserve an untapped wealth of information concerning the habit and ecology of the parent plant as well as the vegetation structure of the landscape. The primary goal of this project is to develop anatomical proxies for interpreting three parameters of whole-plant ecophysiology from leaf fossils using the emerging mechanistic understanding of how leaf structure and physiology are linked. 1) Plant habit -tall tree or low shrub- is provided from variance in vein density between leaf compressions with similar total vein number. 2) Adaptation to water vapor pressure deficit -a sunny, exposed environment or a shaded, understory environment- is provided by the ratio of the vein-vein and vein-leaf surface distances in anatomically preserved leaf fossils. 3) Carbon assimilation and transpiration capacities are provided by the density of veins per leaf surface area in leaf compressions. These tools will be established with a phylogenetically and ecologically diverse series of field-based measurements in both tropical and temperate forests, as well as greenhouse and growth chamber experiments to simulate conditions that no longer exist in the modern world. First applications will focus on the ecophysiology of key fossils during the Cretaceous/Early Cenozoic diversification of flowering plants and the late Paleozoic diversification of seed plants - key topics in their own right, but also important for the introduction of these techniques to the larger paleontological community.A crucial point is that the proxies are based in understood physiological mechanisms, not just in statistical correlations. Thus, they will be available to all paleontologists interested in any period of plant evolution from the first leaves and forests in the Devonian through to the Recent. These tools will aid reconstruction of fossils and understanding of the evolution of physiology and ecology. More broadly, this work will provide a new approach for constraining past climates and the carbon and hydrological cycles of deep time.