Lv. Dever et al., THE ISOLATION AND CHARACTERIZATION OF MUTANTS OF THE C-4 PHOTOSYNTHETIC PATHWAY, Journal of Experimental Botany, 46, 1995, pp. 1363-1376
Three novel classes of the C-4 plant Amaranthus edulis are described.
(1) A mutant that contains less than 10% of the normal activity and pr
otein of phosphoenolpyruvate carboxylase. (2) A mutant that is deficie
nt in NAD-malic enzyme activity, but contains the normal two subunits
of the enzyme protein. (3) Four mutant plants that accumulate high con
centrations of glycine following exposure to air. A common characteris
tic of all the mutant plants is that they grow poorly in air and exhib
it very low rates of photosynthetic CO2 assimilation. The characterist
ics of the mutant lines are discussed with reference to our current kn
owledge of the regulation of the C-4 photosynthesis pathway. The possi
bility that C-4 plants undergo photorespiratory nitrogen and carbon me
tabolism when grown in air is considered in detail.