Search

Peperomiahas species that may be C3, show Crassulacean acid metabolism (CAM), or CAM‐cycling. Species that show CAM progress from C3to CAM through CAM‐cycling during leaf development. In CAM and CAM‐cycling species, CAM metabolism is predominately in the upper multiple epidermis and lower spongy mesophyll, whereas C3metabolism is localized mostly in the palisade mesophyll. Using specific protein and cDNA probes prepared from P‐enolpyruvate carboxylase (PEPc) and ribulose‐1,5‐bisphosphate carboxylase (Rubisco), we have now studied the differential distribution of photosynthetic metabolism in Peperomialeaves using the technique of tissue printing. The tissue printing studies detected Rubisco protein in leaves of C3P. orba, but not PEPc. Young C3leaves of P. scandensand P. camptotrichashowed Rubisco protein, but not PEPc; however, the mature leaves of these two species that have CAM showed PEPc protein and RNAs in both the multiple epidermis and spongy mesophyll. In contrast, Rubisco protein and RNAs were present throughout the leaf. The tissue printing data are consistent with our previously published data showing the differential distribution of photosynthetic metabolism in leaves of Peperomia.Although the tissue printing technique is qualitative, coupled with quantitative data it has proven useful for the study of function related to structure.