Whole leaf photosynthetic light response in a carnivorous plant species Sarracenia alata

Abstract

Photosynthetic light-response curves of mature leaves of Sarracenia alata were generated and characterized using a custom built chamber (2.79 L) capable of accommodating whole leaves, or pitchers, coupled to a LI-COR 6400XT Portable Photosynthesis System. In addition to generating light-response curves, chlorophyll content, leaf area, and dry mass measurements were obtained for each pitcher. Gas-exchange variables from the light-response curves are reported on a leaf area and dry mass basis. Calculated light-saturated photosynthesis was found to be 2.09 µmol(CO2) m-2 s-1 with a light-saturation point of 315.14 µmol(photon) m-2 s-1, light-compensation point of 40.25 µmol(photon) m-2 s-1, dark respiration rate of -0.57 µmol(CO2) m-2 s-1, and apparent quantum efficiency of 0.033. The use of a large custom built chamber proved to be successful and the data presented indicate that adequate mixing and sampling was achieved. This study is the first to document photosynthetic response of S. alta. The data from this study indicate that S. alata collected from our study site photosynthetically performed like that of a shade-adapted C3 plant and the measurements were consistent with those published for other species of Sarracenia.

Keywords

• chlorophyll; gas exchange; leaf morphology; respiration; stomatal conductance.