Greenleaf Nursery Co., Inc.

The effects of NaCl, CaCl₂, and MgCl₂ on the absorption of Rb by excised roots and intact seedlings of S. alterniflora, and of NaCl on Rb absorption by D. spicata, were studied.In both species, the rate of Rb absorption was reduced when the concentration of NaCl in the external solution was ≥10 mM NaCl.The reduction was proportional to the concentration of NaCl.In S. alterniflora the Ca concentration for maximum Rb absorption by excised roots was 2 mM, ∼4 times that reported for nonhalophytes.Mg at concentrations ≤40 mM was a poor substitute for Ca, as the Mg-mediated Rb absorption was by a factor of 2-3 slower than Ca-mediated absorption.