Broad-range effects of ionophore X-537A on pollen tubes of Lilium longiflorum.

The effects of the broad-range cationophore X-537A on pollen tubes of Lilium longiflorum were investigated, using both light and electron microscopy. Pollen tube growth is completely inhibited within 30 min after the application of 5·10(-5) M ionophore X-537A; cytoplasmic streaming is stopped only after 60 min of ionophore treatment. Ultrastructurally, X-537A effects are a vacuolation of Golgi cisternae and a general vacuolation. The wall is thickened at the very tip. Coated vesicles and coated regions are enriched close to and at the plasma membrane. The results indicate that pollen tube tip growth needs a specific ion distribution.