Leaf Angles, Leaf Area, and Canopy Photosynthesis¹

Abstract

For leaf area indices (LAI) of less than approximately 3.0, differences in leaf angle are predicted by computer simulation to have only small effects on canopy photosynthetic rates. For higher LAI values, layers of vertical and horizontal leaves can be arranged to give both the highest and lowest possible rates of canopy photosynthesis for the conditious assumed. These arrangements of leaf layers and angles are not much affected by leaf type or latitude within usual limits. The ratio of highest to lowest photosynthetic rate varied from 1.14 at LAI 3.0 to 2.0 at LAI 10.0. Calculations with one set of corn ( Zea mays L.) descriptions indicate that canopy photosynthetic rates may range from 92% of theoretical maximum at LAI 3.0 to 76% at LAI 7.0.