Identification of tropical grasses with the C-4 photosynthetic pathway by their leaf anatomy

Abstract

The leaf anatomy of 75 forage grass species from 30 genera and one interspecific hybrid was studied to classify them, by the presence or absence of the Kranz-type mesophylic cell structure, in respect to their photosynthetic pathway.  72 of the species presented characteristic Kranz-type leaf anatomy, indicating the C-4 dicarboxylic acid photosynthetic pathway, while 3 (Acroceras macrum, Pharus sp. and Bambusa sp.) showed no Kranz-type, indicating the C-3 Calvin cycle. Characteristic Kranz-type structures are described and ilustrated. In general, plants from the same tribe show similar structure.  It is concluded that all tropical forage grasses of economical importance are C-4 plants.