ISSN:
1615-6102
Keywords:
Caffeine
;
Freeze substitution
;
Lilium
;
Pollen tubes
;
Rapid freeze fixation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary In an attempt to correlate structural effects with the known dissipation of the tip-focused Ca2+ gradient caused by caffeine, we have examined the ultrastructure of caffeine-treated lily pollen tubes prepared by rapid freeze fixation and freeze substitution. We show that treatment with caffeine results in a rapid rearrangement of secretory vesicles at the pollen tube tip; the normal cone-shaped array of vesicles is rapidly dispersed. In addition, microfilament bundles appear in the tip region, where they had previously been excluded. Delocalized vesicle fusion continues in the presence of caffeine but tube extension ceases. Removal of caffeine from the growth medium initially causes tip swelling, delocalized vesicle fusion and presence of microfilaments well into the tip before normal structure and growth resume, concurrent with the previously reported return to a normal Ca2+ gradient.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01281055
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