PHOTOSYNTHESIS IN THE MANGROVE SPECIES RHIZOPHORA-MANGLE-L - NO EVIDENCE FOR CAM-CYCLING

Recently, Werner and Stelzer reported C3 gas exchange simultaneous wit h CAM acid fluctuations, i.e., CAM-cycling, in seedlings of the mangro ve species Rhizophora mangle L. The potential for CAM-cycling was inve stigated in mature individuals of R. mangle and of Laguncularia racemo sa (L.) Gaertn. f in situ in southwestern Florida and in seedlings of R. mangle grown in a growth chamber. Only C3 CO2 exchange was observed , while diurnal fluctuations of tissue acid content were absent. Thus, no evidence for CAM-cycling was found '' the field or in the growth c hamber for R. mangle, nor in the field for L. racemosa.