Sodium does not compete with calcium in saturating plasma membrane sites regulating na influx in salinized maize roots.
Half maximal inhibition of sodium ((22)Na(+)) influx into maize (Zea mays L.) root segments incubated in solutions containing from 0.25 to 100 millimolar NaCl was consistently attained with external calcium activity at 0.26 +/- 0.10 millimolar. Sodium ions do not appear to compete with calcium during initial binding to sites on the plasma membrane that participate in the regulation of sodium influx under saline conditions.
Zidan
I
I
Plant Physiology Laboratory, Faculty of Agricultural Engineering, Technion IIT, Haifa 32000, Israel.
Jacoby
B
B
Ravina
I
I
Neumann
P M
PM