Figure 3

The circadian clock organized expression of maize photosynthesis, carbohydrate metabolism, and cell wall synthesis genes. Maize genes encoding enzymes associated with the CO ₂ capture steps of C4 photosynthesis, which take place in mesophyll cells, showed coordinated expression phased to morning (ZT20 and ZT0) and midday (ZT4). Expression of genes encoding enzymes of the Calvin cycle, which occurs in bundle sheath cells, was generally phased to early morning (ZT16 and ZT20). Expression of genes encoding enzymes involved in cell wall synthesis, which are illustrated in a separate cell for clarity, occurred in the morning (ZT20 and ZT0). Large light blue shapes represent cells and green boxes within cells represent chloroplasts. Small dark blue boxes indicate genes on the array and red boxes are genes absent from the array. White clock faces next to enzymes indicate the circadian expression of the gene encoding that enzyme and the number within the clock face shows the expression phase in ZT.