Physiological responses of semiarid grasses. IV.* Photosynthetic rates of Thyridolepis mitchelliana and Cenchrus ciliaris leaves

Abstract

Photosynthesis response curves of mulga and buffel grasses to irradiance and to carbon dioxide concentration, together with studies of leaf anatomy and chloroplast structure, showed that the former was a C₃ and the latter a C₄ species. This is held to account for the large differences in growth rate between the two species.

Although Mitchell grass has the anatomy of a C₄ species, its photosynthetic responses were not examined. As its net assimilation rate is high at high temperatures, its generally low growth rates are associated with the poor development of its leaf surface.

*Part III, Aust. J. Aguic. Res., 26: 447 (1975).