Progress in Coupling Plant Form and Photosynthetic Function


William K. Smith

Additional Authors:

Nicole M. Hughes


March 2009


ABSTRACT Photosynthetic adaptation in terrestrial vascular plants involves a complex interaction of components that extend across a broad structural and spatial hierarchy, often functioning in concert with one another at multiple scales. Thus, understanding the evolutionary mechanisms leading to these adaptations requires evaluation across the entire spectrum of plant form from the chloroplast to the landscape. Adaptive traits across this structural/spatial hierarchy can emerge at any level and then feed-back or feed-forward to cause adaptive changes at adjacent levels. Today’s sophisticated instruments enable direct measurement of photosynthesis at most of these hierarchical levels and across phylogenetic boundaries. As a result, identification of functional properties in plant form (architectural and spatial), independent of physiological processes, is becoming a reality. In this review we focus on one apparent theme across this hierarchy of organizational complexity—the impact of plant form on the distribution of incident sunlight to photosynthetic surfaces, and the transfer and processing of mass nutrients (e.g. CO2 and water). The trade-offs and net effects of these exchange processes drive photosynthetic adaptation, and appear to be related to economic efficiencies rather than simply magnitude.