The marked plasticity inherent in plant cells is elegantly illustrated by development of the single-celled C4 syndrome in cotyledons of Borszezowia aralocaspica. Voznesenskaya et al. (pp. 177-187) demonstrate conversion from storage function to C4 photosynthetic function within an individual cell that is induced by light. The process includes polarization of organelle location and biochemical specialization at opposite ends of mature cells.