CARBON, NITROGEN AND WATER USE OF C3, C4 AND CAM PLANTS. COMPARATIVE ASPECTS.
The different pathways of photosynthetic CO2 fixation of C3, C4 and CAM plants are now commonly recognized as adaptation to specific environmental conditions. C4 and especially CAM plants can fix CO2 at much lower water cost than C3 plants, because they can function with lower stomatal conductance and transpiration rate. On the other hand the transport rate of mineral nutrients, e. g. nitrate, in the xylem of the plants from the source (i.e. the soil) to the sink (i.e. the leaves) rises with increasing transpiration. So low transpiration rates, regarded as a competitive advantage under low water conditions, are revealed to be detrimental to C4 and CAM plants competing with C3 plants under low nitrogen conditions when sufficient water is available.
Gebauer, G. (1988). CARBON, NITROGEN AND WATER USE OF C3, C4 AND CAM PLANTS. COMPARATIVE ASPECTS.. Acta Hortic. 229, 73-84