Observations on microtubules and nuclei motility in the pollen tube of olive [Olea europaea L.]

In order to study microtubule organization during pollen germination and pollen tube growth in Olea europaea, we applied immunofluorescence microscopy using mouse monoclonal antibody against α-tubulin as primary antibody and FITC-conjugated goat antimouse IgG as secondary antibody. DAPI enabled observation of the vegetative nucleus entering the emerging pollen tube before the generative cell. The latter then overtakes the vegetative nucleus once both are inside the pollen tube. The generative cell remains ahead of the vegetative nucleus until it is finally divided into two gametes. This cell division occurs when the generative cell is close to the tip of the pollen tube. Possible connections between microtubules and nuclear migration in the pollen tube are discussed.