The effect of night temperature and leaf inorganic nitrogen status on the C₄ Pathway enzymes in selected C₄ photosynthetic grasses

Abstract

Themeda triandra, Hyparrhenia hirta and Zea mays have a single bundle sheath with agranal, centrifugal chloroplasts suggesting a NADP‐ME‐type photosynthetic pathway. Plants grown in liquid cultures had a higher NADP malic enzyme activity than those grown in sand with nutrients being supplied. Decreased minimum night temperature and infiltration of inorganic nitrogen ions appeared to affect the decarboxylating systems of these species suggesting that this pathway is variable under different environmental conditions. Results are discussed in relation to nomenclature of the three distinct anatomical and biochemical C₄ photosynthetic types.