Fig. 4 KNOX (Kn) and PHANTASTICA (Phan) gene expression
patterns presage the switching from indeterminate to determinate
cell fate. (a) The auxin patterning process leads to a local area of auxin
accumulation. (b) The local site of auxin accumulation corresponds to
the area in which KNOX gene expression is lost. This leads to derepression
of PHANTASTICA-like gene expression which is required for repression
of KNOX gene expression in the young leaf primordium. Loss of KNOX
gene expression and gain of PHANTASTICA-like gene expression
leads to determinancy of cell fate.