Research at channel level on the effect of LaCl3 on Radish (Raphanus satirus L.) vacuolar membrane

We recorded slow vacuolar (SV-type) channel currents of Radish vacuoles successfully for the first time by using the whole-vacuolar patch-clamp recording mode. SV-type currents would increase and threshold potentials of activation would shift towards more negative values with the increase of concentrations of cytosolic Ca²⁺. When 2.5 mmol/L LaCl₃ and 4 mmol/L EGTA were added to bath solutions, SV-type currents were suppressed remarkably. Then adding LaCl₃ with different concentrations to pipette solutions, we found that LaCl₃ with higher concentrations (>4 × 10⁻⁷ mol/L) had a strong inhibitory effect on SV-type currents, while LaCl₃ with lower concentrations (⩽4 × 10⁻⁷ mol/L) promoted channel currents. This promoting effect provides an important basis at channel level for researching further the effects of rare earth on physiological activities of plants and the production-increase effects of rare earth fertilizers on crops.