Abstract
The potential for nighttime CO2 uptake and/or increases in tissue acidity characteristic of crassulacean acid
metabolism (CAM) was investigated, to varying degrees, in 12 species of Vittariaceae as well as in seven species
in four other families of tropical epiphytic ferns. Evidence of CAM (actually CAM cycling, i.e., diei changes in
tissue acidity without nighttime atmospheric C 0 2 uptake), though highly variable, was found in two species of
Vittariaceae. The ecophysiological significance of this finding is puzzling, because the occurrence of these
plants in deeply shaded, extremely moist habitats is rare, if not unique, among plants expressing any degree of
CAM. The results of this study confirm that CAM among the ferns is not limited to the Polypodiaceae, and
they emphasize the polyphyletic nature of the evolution of CAM among higher plants.
Description
This is the publisher's official version. It is also available electronically from: http://www.jstor.org/stable/10.1086/430334.
Citation
S. L. Martin, R. Davis, P. Protti, T.-C. Lin, S.-H. Lin, and C. E. Martin. 2005. The occurrence of Crassulacean acid metabolism in epiphytic ferns, with an emphasis on the Vittariaceae. Int. J. Plant Sci. 166:623-630.