Leaf ultrastructure in species of Gomphrena and Pfaffia (Amaranthaceae)

Ultrastructural aspects, especially the organization of chloroplasts and their distribution, were studied in leaves of three species of Gomphrena (G. macrocephala, G. prostrata, and G. decipiens) presenting "Kranz anatomy," and in Pfaffia jubata, without that characteristic. In Gomphrena spp. the distribution of chloroplasts according to the complexity of their lamellar system seems to follow a gradient: most of the chloroplasts in the bundle sheath cells have poorly developed grana but some of them, in the cell side opposite to the vascular bundle, may present conspicuous grana. A similar situation occurs in "Kranz mesophyll cells," but in this case grana are more developed. Finally, chloroplasts in "non-Kranz mesophyll cells" have the more developed grana. In P. jubata no differences occur in chloroplast structure, all of them showing well-organized grana. Chloroplasts with well-developed grana were found in vascular parenchyma and in companion cells of Gomphrena spp. and P. jubata.