Photosynthesis and dark respiration of leaves of terrestrial carnivorous plants

Using CO2 gasometry, net photosynthetic (P (N)) and dark respiration rates (R (D)) were measured in leaves or traps of 12 terrestrial carnivorous plant species usually grown in the shade. Generally, mean maximum P (N) (60 nmol CO2 g(-1)(DM) s(-1) or 2.7 mu mol m(-2) s(-1)) was low in comparison with that of vascular non-carnivorous plants but was slightly higher than that reported elsewhere for carnivorous plants. After light saturation, the facultatively heliophytic plants behaved as shade-adapted plants. Mean R (D) in leaves and traps of all species reached about 50% of maximum P (N) and represents the high photosynthetic (metabolic) cost of carnivory.