Abstract
Peperomia is a large pantropicalgenus ofmore than 600 species, manyofwhich are epiphytes. A survey indicates that 50% or more ofthe species have Crassulacean acid metabolism (CAM) or CAMcycling. Our assessment of93 taxa is based on the enzymic activities ofP-enolpyruvate carboxylase (PEPc) and pyrophosphate: fructose 6-phosphate phosphotransferase (PFP), diurnal organic acid fluctuation, and nocturnal gas exchange and stomatal opening. During development, the leaves ofthe CAM Peperomia spp. shift from C3-photosynthesis to CAM as evidenced by the appearance of PEPc, the commencement of diurnal organic acid fluctuation, and by a shift from daytime gas exchange to nocturnal gas exchange. There
is some evidence that water-stress will accelerate the induction ofCAM during development. CAM activity may be seasonal in some species, with more activity during the spring and summer than in the winter when growing in glasshouses. Since the photosynthetic mode ofPeperomia may change in response to environmental perturbations such as water-stress, changing photoperiods, seasonally, and during development, the assignment ofa particular mode to a species may be equivocal. Thus, it is possible that all species have some CAM capacity. The presence of CAM metabolism in this epiphytic genus suggests adaptation to drought and water-stress conditions.
Open Access and Copyright Notice
Selbyana is committed to real and immediate open access for academic work. All of Selbyana's articles and reviews are free to access immediately upon publication. There are no author charges (APCs) prior to publication, and no charges for readers to download articles and reviews for their own scholarly use. To facilitate this, Selbyana depends on the financial backing of the Marie Selby Botanical Gardens, the hard work and dedication of its editorial team and advisory board, and the continuing support of its network of peer reviewers and partner institutions.
Authors are free to choose which open license they would like to use for their work. Our default license is the Creative Commons Attribution-NonCommercial 4.0 (CC BY-NC 4.0). While Selbyana’s articles can be copied by anyone for noncommercial purposes if proper credit is given, all materials are published under an open-access license with authors retaining full and permanent ownership of their work. The author grants Selbyana a perpetual, non-exclusive right to publish the work and to include it in other aggregations and indexes to achieve broader impact and visibility.
Authors are responsible for and required to ascertain that they are in possession of image rights for any and all photographs, illustrations, and figures included in their work or to obtain publication or reproduction rights from the rights holders. Contents of the journal will be registered with the Directory of Open Access Journals and similar repositories. Authors are encouraged to store their work elsewhere, for instance in institutional repositories or personal websites, including commercial sites such as academia.edu, to increase circulation (see The Effects of Open Access).