Ultrastructural Observations in the Suppression of Granal Development in Bundle Sheath Chloroplasts of NADP-ME Type C₄ Monocot and Dicot Species

Abstract

We examined chloroplast development with respect to the stacking of grana in Zea mays L., an NADP-ME type C₄ monocot, and in Portulaca grandiflora, an NADP-ME type C₄ dicot species. In both species, mean numbers of thylakoids per granum in bundle sheath chloroplasts were suppressed less than 3 throughout chloroplast development while they were increased gradually in mesophyll chloroplasts. It was concluded that in both phylogenetically distinct NADP-ME type C₄ plants the stacking of grana was suppressed in bundle sheath chloroplasts from early developmental stages.