Cross section of a mature leaf of the C4 species Atriplex rosea showing the striking structural differentiation
of bundle sheath and mesophyll tissue. During leaf development, a bundle
sheath-specific enzyme, RuBPCase, is expressed, coincident with vein delimitation.
Later, a mesophyll-specific enzyme, PEPCase, accumulates, after formative divisions have ceased.
copyright: Nancy G. Dengler, BSA