and ions such as sodium and potassium (
Turner, 1979
)isa
common metabolic response of higher plants to maintain water
balance and avoid water stress. The role of K
+
in the regulation of
plant water status is well known. Potassium is the main solute
involved in cell osmotic water absorption (
Hsiao and Läuchli,
1986
), the maintenance of cell turgor pressure and cell elongation,
and theregulationofstomatalopening(
FischerandHsiao,1968
).