Document: JOH-3-29-11

Modeling the light interception and carbon gain of individual fluttering leaves.

RODEN, J.S.*

Southern Oregon University, Ashland, OR 97520 ¹

Abstract:
Poplars (Populus spp.) have a particular petiole morphology that enhances leaf flutter in the wind. Previous studies have shown that this trait enhances whole canopy carbon gain through changes in the temporal dynamics and spatial distribution of light in the lower canopy. However, less in known about the effects of flutter for leaves at the top of the canopy. The model uses latitude, time of day, day of year, azimuth and a slope component, which is varied at a 3 Hz frequency over an arc of rotation to create the flutter motion, to generate light interception on both surfaces of a fixed or fluttering leaf. The light files generated (10 Hz) are input into a dynamic model of photosynthesis to estimate the carbon gain for both fluttering and fixed leaves. As compared to leaves fixed at various angles and azimuths, fluttering leaves have a more uniform light interception. Depending on their angle and azimuth, fixed leaves may not always be intercepting high light even when exposed to full sun. Leaf flutter continuously randomizes leaf angles creating uniform light inputs for photosynthetic reactions regardless of the variability of leaf orientation and solar position. These effects on light interception could have positive impacts on carbon gain for leaves at the top of the canopy.

Keywords: canopy light dynamics, leaf flutter, aspen, computer model, photosynthesis

This abstract is being presented at: 10:30 AM in session:
Poster Session #1: Light Relations.