Theeffectoflanthanumiononmembranepermeabilityofcornrootsegmentisstudied.ResultsshowsthattreatmentoftherootsegmentswithLaCl3·7H2Ocandecreasetheionleakageoftheroottissue.Theleakagedecreaseshyincreasingtheconcentrationoflanthanum,andtheconcentrationhasnofurtherdependenceonionleakagesabove25μmol/L.Aftertreatingtheroottissueforonehourwithlanthanumion,theamountofleak-agehaslineardependenceontimewithinthefirst2handaftertwohourstheleakageincreases.Theionleakageofthetissuedependesonthetimeoflanthanumtreatment.Whenthedurationoftreatmentisprolonged,theleakagedecreasesrapidlyandtheleakagereachesaminimumat30minutes.Otherrareearthelementscanalsodecreaseionleakage.Thereisnosignificantdifferenceintheionleakageamongtheseelements.
