[1] Univ Illinois, USDA ARS, Photosynthesis Res Unit, Dept Plant Biol, Urbana, IL 61801 USA
[2] Univ Illinois, Dept Crop Sci, Urbana, IL 61801 USA
[3] Brookhaven Natl Lab, Dept Environm Sci, Upton, NY 11973 USA
[4] Juelich Res Ctr, ICG 3, D-52425 Julich, Germany