Structure and Function in the Grass Ligule: Mitochondria and Microbodies in the Membranous Ligule of Lolium temulentum L., an Ultrastructural and Cytochemical Study

The ultrastructure and distribution of the mitochondria andmicrobodies within the tissues of the ligule of mature leavesof Lolium temulentum L. are described. Staining of the mitochondriaand microbodies with diaminobenzidine (DAB) was observed. Mitochondrialstaining was totally inhibited by potassium cyanide and sodiumazide but not by aminotriazole, and did not occur in the presenceof added hydrogen peroxide; it was concluded that cytochromec oxidase (EC 1.9.1.3 EC] ) was responsible. In the microbodies stainingwas reduced in the absence of added hydrogen peroxide and eliminatedin the presence of aminotriazole; it was concluded that catalase(EC 1.11.1.6 EC] ) was responsible. Presence of succinic dehydrogenase(EC 1.3.99.1 EC] ) activity was demonstrated in the mitochondriausing the copper-ferricyanide reaction; presence of sodium malonateand absence of sodium succinate greatly reduced mitochondrialdeposition of reaction product. The results are discussed inrelation to possible functions of these organelles in the ligule. Key words: Ligule, Lolium temulentum L., Enzyme ultracytochemistry