VISUALIZATION OF THE CA2+-GRADIENT IN GROWING POLLEN TUBES OF LILIUM-LONGIFLORUM WITH CHLOROTETRACYCLINE FLUORESCENCE

Epifluorescence microscopy with chlorotetracycline (CTC) fluorescence was used to visualize the Ca2+ distribution in germinating pollen grains and growing pollen tubes of Lilium longiflorum. The intensity of the fluorescence shows a gradient with the highest fluorescence at the growing tip. Added external Ca2+ influences the intensity of the gradient in germinating grains. Ionophore A 23187 treated pollen tubes do not show the fluorescence gradient with CTC. These results are interpreted as evidence for the role of a Ca2+ gradient in pollen tube tip growth. © 1978 Springer-Verlag.