The role of cyclic nucleotides cAMP and cGMP as secondary messengers in animal cells is well established. Less is known about their role in plants though the presence of both cGMP and cAMP has unequivocally been demonstrated (1). Furthermore, cGMP has been shown to be involved in phytochrome signal transduction and in hormone signalling whereas cAMP plays a role in cell cycle progression and pollen tube growth (2). In my lab we are interested in cyclic nucleotide signalling with respect to plant salt tolerance and nutrition. We found that Arabidopsis root cells contain cyclic nucleotide sensitive ion channels that are likely involved in Na+ uptake and that application to the root medium of cyclic nucleotides decreases unidirectional Na+ influx, Na+ accumulation, and plant death (3). We are trying to identify other elements of this putative signalling pathway. For example, in collaboration with Prof v Onckelen (University of Antwerp) we are testing whether an alteration in cytoplasmic cAMP/cGMP forms part of an early signalling event in response to salt stress.