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Chapter 1 - Light use and leaf gas exchange


Leaves come in a variety of shapes and sizes. Soybean (Glycine max) has a trifoliate leaf with broad laminae designed for capturing the maximum amount of light in a dense canopy.

John R Evans and Susanne von Caemmerer, Research School of Biology, Australian National University

Leaves come in a great variety of shapes and sizes. The photosynthetic processes that occur within leaves also show considerable variation. All of these variations represent different adaptive responses to different environmental conditions leading to altered gene expression.  

Despite such variation, leaves fulfil a common purpose: to capture energy from sunlight and convert that energy currency into chemically useful forms to drive CO2 assimilation and subsequent growth. CO2 assimilation broadly refers to the first steps in the production of sugars from CO2 and water, that is the initial incorporation of inorganic CO2 into biological molecules. Light absorption and energy utilisation is considered at progressively finer levels of organisation from leaves (Section 1.1) to chloroplasts (Section 1.2).

Section 1.1 encompasses anatomy, light interception and leaf gas exchange and includes a case study on development of a process-based model for photosynthetic CO2 assimilation using A:Ci curves.