A Comparative Study of the Leaf Anatomy of the Grasses Andropogon ischaetnum and Chrysopogon gryllus

Summary The leaf anatomy of the grasses Andropogon ischaemum and Chrysopogon gryllus was studied at the level of light and electron microscopy. These species are dominating the foot-hill grassland of Northern Greece. The volume of the intercellular airspace system of their leaves was estimated as well. The observations show that both plants have a xeromorphic appearance and belong to the C4 photosynthetic species, because they bear all the characteristics of the Kranz syndrome. The leaves of A. ischaemum have a water storing parenchyma at the top side of the midrip which is absent in C. gryllus. The bundle sheath cell chloroplasts of A. ischaemum bear a great quantity of starch and entirely lack grana, while the corresponding chloroplasts of C. gryllus bear rudimentary grana, but their starch content is far smaller. The cells of the assimilative mesophyll are arranged around the vascular bundles. This arrangement in A. ischaemum is more regular, the cells are elongated and with relatively small intercellular spaces; on the contrary, in C. gryllus, the intersections of these cells are almost circular, resulting in wider intercellular spaces. The chloroplasts of the mesophyll cells in A. ischaemum have peripheral reticulum and better developed grana than in C. gryllus. All these differences indicate that A. ischaemum is better adapted to withstand adverse environmental conditions than G. gryllus.