title: Is Sedum acre L. a CAM plant?
abstract: Sedum acre L. collected from its natural stands south of Darmstadt (Germany) showed δ13C values typical for C3plants. This suggests that in situ at the natural stand CO2was fixed mainly via the C3mode of photosynthesis rather than via the CAM mode. However, experimental water stress shifts the CO2exchange pattern from the C3type to CAM type. Simultaneously, a diurnal rhythm of malic acid oscillation, typical for CAM, and increase of PEP-carboxylase and malic enzyme activities developed. Hence, Sedum acre is obviously to be classified as a facultative CAM plant. Because of the temperature characteristics of CO2exchange in Sedum acre, in situ CO2should be harvested from the atmosphere mainly during the seasons where water stress situations capable of inducing CAM are unlikely to occur.
authors.affiliation: Botanisches Institut der Technischen Hochschule Darmstadt, Schnittspahnstr. 3-5, D-6100, Darmstadt, Federal Republic of Germany.
authors.forename: M
authors.initials: M
authors.lastname: Kluge