Enclosure of mitochondria by chloroplasts [Panicum schenckii, serial sectioning and membrane configuration, structure]

In Panicum species of the Laxa group, some of which have characteristics intermediate to C3 and C4 photosynthesis species, some mitochondria in leaf bundle sheath cells are surrounded by chloroplasts when viewed in profile. Serial sectioning of leaves of one Laxa species, Panicum schenckii Hack, shows that these mitochondria are enclosed by chloroplasts. Complete enclosure rather than invagination also is indicated by absence of two concentric chloroplast membranes surrounding the mitochondrial profiles.