Table II.

Changes in ion and polyol content in xylem sap of stressed ice plants

	Controla	NaCl Stressa
Sodium	0.9 ± 0.2	59.5 ± 9.7
Potassium	48.7 ± 4.2	58.1 ± 6.3
Myo-inositol	<0.1	0.6 ± 0.3
d-ononitol	<0.1	1.5 ± 0.6

^a In micromoles/injection volume (50 μL of undiluted xylem sap in each experiment from three plants; n = 6). Plants, grown hydroponically in 0.25 Hoagland nutrient solution and 6 weeks of age, were stressed for 24 h at 400 mm in the medium. Xylem sap was collected from side-shoot segments by pressure bomb extrusion (Nelson et al., 1998). Ions and polyols were determined by HPLC analysis (Adams et al., 1992). Suc was absent or below the limit of detection in the samples.