ULTRASTRUCTURAL OBSERVATIONS IN THE SUPPRESSION OF GRANAL DEVELOPMENTIN BUNDLE-SHEATH CHLOROPLASTS OF NADP-ME TYPE C-4 MONOCOT AND DICOT SPECIES

We examined chloroplast development with respect to the slacking of gr ana in Zea mays L., an NADP-ME type C-4 monocot, and in Portulaca gran diflora, an NADP-ME type C-4 dicot species. In both species, mean numb ers of thylakoids per granum in bundle sheath chloroplasts were suppre ssed less than 3 throughout chloroplast development while they were in creased gradually in mesophyll chloroplasts. It was concluded that in both phylogenetically distinct NADP-ME type C-4 plants the stacking of grana was suppressed in bundle sheath chloroplasts from early develop mental stages.