Shedding light on leaves: photosynthesis and functional leaf anatomy
Dr. Daniel Tholen
(University of Natural Resources and Life Sciences, Vienna. Institute of Botany)
The leaf is an intricately formed organ that stands at the border between plant and atmosphere. The leaf captures light and carbon dioxide for use in the process of photosynthesis. At the same time, a leaf can prevent excess light absorption and control water losses by transpiration. The leaf anatomy contributes to the maintenance of a stable internal environment and facilitates all these physiological processes. In addition, the anatomy provides the structural integrity that allows leaves to operate under mechanical stresses such as gravity, wind, rainfall and herbivory. In this talk, I will provide an overview of the variation in leaf anatomy and discuss how leaf structure relates to optical properties, gas-exchange and water transport. I will review several techniques that are commonly used to examine functional leaf anatomy. Novel approaches such as serial sectioning and X-ray microcomputed tomography allow for a three-dimensional
description of the anatomy. Such 3D descriptions reveal short-comings in often used representations of the anatomy. In addition, these approaches make it possible to build spatially-explicit models of physiological processes happening in the leaf and give insight in how leaf form affects leaf function.