Dark respiration of leaves and traps of terrestrial carnivorous plants: are there greater energetic costs in traps?

In this study, O₂-based dark respiration rate (R_D) in leaf and trap cuttings was compared in 9 terrestrial carnivorous plant species of 5 genera to decide whether traps represent a greater energetic (maintanence) cost than leaves or photosynthetic parts of traps. R_D values of cut strips of traps or leaves of terrestrial carnivorous plants submerged in water ranged between 2.2 and 8.4 nmol g⁻¹ s⁻¹ (per unit dry weight) in pitcher traps of the genera Sarracenia, Nepenthes, and Cephalotus, while between 7.2 and 25 nmol g⁻¹ _DW s⁻¹ in fly-paper or snapping traps or leaves of Dionaea and Drosera. No clear relationship between R_D values of traps (or pitcher walls) and leaves (or pitcher wings or petioles) was found. However, RD values of separated Drosera prolifera tentacles exceeded those of leaf lamina 7.3 times.