Crassulacean acid metabolism (CAM) is an alternative photosynthetic mode that achieves high water use efficiency through nocturnal CO₂ uptake and daytime stomatal closure. Crop plants that undergo CAM would be particularly attractive alternatives to C₃ crops for agricultural production in semi-arid, water-limited environments and there is increased interest in engineering CAM into C₃ crops (DePaoli et al., 2014). Mesembryanthemum crystallinum is a halophyte and facultative CAM plant, with the ability to switch its pathway of CO₂ assimilation from C₃ metabolism to CAM in response to environmental cues including water deficit, salinity or high light. This ability for photosynthetic plasticity makes it an extremely useful model experimental system for understanding the underlying molecular mechanisms of the CAM pathway and additionally, the mechanisms of environmental induction of complex traits in plants. Our lab has been using the specialized model trichomes called epidermal bladder cells that line the aerial parts of M. crystallinum as a single cell type system to gain further understanding of CAM and salt-tolerance mechanisms. Transcriptomics, proteomics, metabolomics and ionomics studies have allowed an integrated understanding of the role of these cells, with results contradicting earlier reports these cells were solely repositories for sodium and water (Oh et al., 2015; Barkla et al., 2012; Barkla et al., submitted; Barkla and Vera-Estrella, 2015).  Our findings show that photosynthesis and primary metabolism in the cell supports cell growth, ion accumulation, compatible solute synthesis and CAM.