Isolation and electrical characterization of tonoplast vesicles from the Kiwi fruit (Actinidia chinensis)

Nomarski interference microscopy technique showed that the cell juice of the Kiwi fruit (Actinidia chinensis Planch.) is rich in membrane vesicles that resemble protoplasts and free vacuoles. These vesicles are obtained without enzyme or chemical treatment and probably arise from the rupture and revesiculation of the tonoplasts that limit the cytoplasmic strands of the cells. Vacuole fragmentation in situ probably causes the tonoplast to recombine around the vacuolar sap as well as around the cytoplasmic strands, which implies either original or inverse orientation of the inner face. Electrophysiological measurements in vesicles judged to have the original membrane orientation showed that their polarization was inside positive, the same as central vacuoles of protoplasts and isolated vacuoles.