Persistently sub-optimal environmental conditions constitute stress. Perception and signaling lead to protein expression changes, the activation of new biochemical pathways, and repression of others which are characteristic of the unstressed state. Protective metabolic adaptations alter physiological reactions of the whole plant. Paramount among the mechanisms are oxygen radical scavenging, mai...

Disorders of water balance lead either to dehydration or overhydration. Because there is an intimate relationship between water and sodium concentration (water generally following salt), one can distinguish hypotonic, isotonic and hypertonic dehydration and the same for overhydration. The vast majority of water balance disorders are acquired. In this article, the focus is on the inherited disor...