Guard Cell Protoplasts: Isolation, Culture, and Regeneration of Plants

The guard cells that flank stomata undergo environmentally induced, turgor-driven cellular movements that regulate stomatal dimensions. Under many environmental conditions, changes in stomatal dimensions regulate rates of transpiration and photosynthetic carbon fixation (1). Among the environmental signals that guard cells receive and transduce are light quality, light intensity, intercellular concentrations of leaf carbon dioxide, and apoplastic concentrations of abscisic acid (ABA) (2). How guard cells integrate the variety of signals present in the environment and activate the appropriate signal transduction mechanisms to adjust stomatal dimensions for prevailing environmental conditions is the subject of intense investigation (3).