bundles of C4 pathway plants
1) they have a large number of the chloroplasts
2 ) they have thick walls which are impervious to the exchange of the gases...
the special structure of leaves in C4PLANTS (e.g. maize) where the tissue equivalent to the spongy mesophyll cells is clustered in a ring around the leaf veins, outside the bundle-sheath cells. (The term ‘Kranz’ means wreath or ring in German). The bundle-sheath cells contain large CHLOROPLASTS whereas the spongy mesophyll cells have few if any chloroplasts, unlike their counterparts in C3 plants (see MESOPHYLL).