Diurnal leaf amino acid profiles confirm heavily disturbed photorespiratory metabolism in the mtkas-1, mtkas-2, and mtkas-3 mutants in comparison with wild-type plants. Light (white boxes) and dark periods (black boxes) are indicated. Symbols and error bars for wild-type (square), mtkas-1 (rhombus), mtkas-2 (triangle), and mtkas-3 (circle) plants grown in normal air represent means ± se from three samples.