Second messengers in guard cells

Experimental investigations of stomatal guard cells have provided valuable insights into the mechanisms which may underlie signalling in plants. To date a variety of second messengers/signalling elements have been implicated in the control of guard cell physiology and in the perception of important physiological stimuli which affect this cell type. The present paper examines such evidence, placing particular emphasis on the role of calcium-mobilizing second messengers. The possibility that several distinct signalling pathways may operate in the guard cell is discussed, as are the important implications that this may have for signalling in this and other plant cell systems.