IMMUNOLOCALIZATION OF H+-ATPASES IN THE PLASMA-MEMBRANE OF POLLEN GRAINS AND POLLEN TUBES OF LILIUM-LONGIFLORUM

A heterogeneous distribution of H+-ATPase was visualized in germinated pollen of Lilium longiflorum using monoclonal antibodies raised against plasma membrane H+-ATPase. Immunolocalization studies of protoplasts and subprotoplasts derived from pollen tubes and sectioned pollen grains and pollen tubes show that H+-ATPases are abundant in the plasma membrane of pollen grains but are absent or sparsely distributed in the plasma membrane of pollen tubes. This polar distribution of H+-ATPases is probably the basis of the endogenous current pattern measured in growing lily pollen and involved in pollen tube tip growth.