2ND MESSENGERS IN GUARD-CELLS

Experimental investigations of stomatal guard cells have provided valu able insights into the mechanisms which may underlie signalling in pla nts. To date a variety of second messengers/signalling elements have b een implicated in the control of guard cell physiology and in the perc eption 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 cel l is discussed, as are the important implications that this may have f or signalling in this and other plant cell systems.