| The effect of salinity on leaf water relations, and rate and ionic composition of leaf secretion was investigated in plants of Avicennia germinans growing under controlled salinity conditions. Increases in salinity from 0 to 940 mol NaCl m-3 reduced the predawn water potential from -0.56 to -4.16 MPa and the solute potential from -2.27 to -4.48 MPa, whereas the pressure potential remained positive in all treatments. Compared to the control, at 940 mol NaCl m-3 Na+ and Cl- concentrations of leaf sap increased 19 and 7 times, respectively. With the addition of salt the main ions accumulated in leaves were Na+ and Cl- whereas plants grown without salt accumulated K+ in leaves at levels similar to those of Na+ with salt treatments. Secretion rates of Na+ and... |
