This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Martin, C. E. Articles by Zee, A. K. Search for Related Content PubMed PubMed Citation Articles by Martin, C. E. Articles by Zee, A. K. Agricola Articles by Martin, C. E. Articles by Zee, A. K.

Articles

C₃ Photosynthesis and Crassulacean Acid Metabolism in a Kansas Rock Outcrop Succulent, Talinum calycinum Engelm. (Portulacaceae) ¹

Department of Botany, University of Kansas, Lawrence, Kansas 66045

The potential for Crassulacean acid metabolism (CAM) was investigated in the sandstone outcrop succulent Talinum calycinum in central Kansas. Field studies revealed CAM-like diurnal acid fluctuations in these plants. These fluctuations persisted under all moisture and temperature regimes in the laboratory. Despite this CAM-like acid metabolism, simultaneous gravimetric determinations of day- and nighttime transpiration rates indicated the presence of a C₃ gas exchange pattern. Subsequent analyses of diurnal CO₂ and H₂O exchange patterns under well-watered conditions and after 3, 5, and 7 days of drought confirmed these findings, though low rates of nocturnal CO₂ uptake were observed on the fifth night after continuous drought. Finally, the ¹³C/¹²C value of this succulent, –27.8, emphasizes the insignificance of any nocturnal CO₂ uptake in the lifelong accumulation of carbon in this species. Thus, it is proposed that T. calycinum is a C₃ plant with some CAM characteristics, including the ability to re-fix respiratory CO₂ at night under all moisture regimes, potentially resulting in a conservation of carbon, and occasionally to fix atmospheric CO₂ at night. These findings may prove to be common among rock outcrop succulents.

This article has been cited by other articles:

				A. Herrera Crassulacean acid metabolism and fitness under water deficit stress: if not for carbon gain, what is facultative CAM good for? Ann. Bot., February 1, 2009; 103(4): 645 - 653. [Abstract] [Full Text] [PDF]

				K. Winter, M. Garcia, and J. A. M. Holtum On the nature of facultative and constitutive CAM: environmental and developmental control of CAM expression during early growth of Clusia, Kalanchoe, and Opuntia J. Exp. Bot., May 1, 2008; 59(7): 1829 - 1840. [Abstract] [Full Text] [PDF]