title: Two functionally different vacuoles for static and dynamic purposes in one plant mesophyll leaf cell.
abstract: It is a common belief that plant mesophyll cells are occupied up to 95% by a single multipurpose vacuole. The common ice plant, Mesembryanthemum crystallinum L., however, requires two contrasting functions of the vacuole under salt stress. Large amounts of NaCl have to be sequestered permanently for osmotic purpose and for protecting the cytoplasm from NaCl toxicity. A dynamic exchange with the cytoplasm is required because photosynthesis proceeds under these conditions via the metabolic cycle of crassulacean acid metabolism (CAM). Nocturnally acquired CO2 must be kept as malate in the vacuole and re-mobilized in the daytime. Here, we show that two large independent types of vacuoles with different transport properties meet the requirements for the contrasting functions within the same cell.
authors.affiliation: Institute for Botany, Darmstadt University of Technology, Schnittspahnstrasse 3-5, 64287 Darmstadt, Germany.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Epimashko
authors.forename: Tobias
authors.initials: T
authors.lastname: Meckel
authors.forename: Elke
authors.initials: E
authors.lastname: Fischer-Schliebs
authors.forename: Ulrich
authors.initials: U
authors.lastname: Lüttge
authors.forename: Gerhard
authors.initials: G
authors.lastname: Thiel
mesh_terms: D006863:Hydrogen-Ion Concentration; D035723:Mesembryanthemum / Q000502:physiology* / Q000648:ultrastructure; D018408:Patch-Clamp Techniques; D018515:Plant Leaves / Q000502:physiology* / Q000648:ultrastructure; D011523:Protoplasts / Q000502:physiology / Q000648:ultrastructure; D014617:Vacuoles / Q000502:physiology* / Q000648:ultrastructure