Na+ extrusion of roots and Na+ excretion of leaves in Malus seedlings with different salt tolerance under NaCl stress

Experiment of split-roots showed that the salt-tolerant Malus seedlings had higher Na+ extrusion capability of roots and whole recirculation amount of Na+ than the salt-sensitive one. This would profit to reduce the shoot Na+ content of salt-tolerant Malus seedlings. Experiment of Na+ excretion showed that the salt-tolerant Malus seedlings also had higher Na+ excretion capability of leaves and whole Na+ excretion capability, moreover, the Na+ excretion per cent of whole Na+ in young and old leaves of salt-tolerant Malus seedlings was higher than that of salt-sensitive one. These made the Na+ content of shoot even less and more salt resistant in salt-tolerant Malus seedlings.