Plants, genes and ions

Ionic homeostasis is a fundamental cellular phenomenon. All living cells maintain an intracellular ionic composition compatible with their constituent molecules, and this requires the regulation of multiple membrane transporters and signal transduction pathways. Other biophysical parameters such as turgor and electrical potential are also part of this essential regulation. How ionic homeostasis is achieved, however, is not completely understood. Although most transporters have already been identified, their physiological function is only starting to be demonstrated and the receptors and most components of the regulatory pathways that effect ionic homeostasis remain unknown. In the case of plants, this problem is related to mineral nutrition and salinity tolerance, both of which have great relevance for agriculture. In fact, as demonstrated by this meeting, salinity stress has been one of the keys to opening the black box of ionic homeostasis in general. Another has been the novel molecular genetics of the plant Arabidopsis thaliana. Of course, other approaches have also contributed to our present understanding of ion homeostasis in plants and were represented at the meeting. For further details, see Blumwald (2000), Hasegawa et al. (2000), Bohnert et al. (2001), Serrano and Rodriguez-Navarro (2001) and Zhu (2001).