Lazzaro MD, Cardenas L, Bhatt AP, Justus CD, Phillips MS, Holdaway-Clarke TL, Hepler PK (2005) Calcium gradients in conifer pollen tubes; dynamic properties differ from those seen in angiosperms.  Journal of Experimental Botany 56:2619-2628

Supplemental videos of pollen tubes.

Videos are in Quicktime format. Download the free Quicktime plugin. You can contact the authors at lazzarom@cofc.edu or see the Lazzaro Lab website at www.cofc.edu/~lazzaro

Figure 1: Conifer pollen tubes have a modest tip focused calcium gradient that pulsates over time as organelles stream in a fountain pattern into the clear zone.

Figure 3:  Injection of 5,5' dibromo-BAPTA, a calcium shuttle buffer, causes several transient increases in cytoplasmic calcium.  Organelles continue streaming in a fountain pattern but elongation stops.

Figure 4: When caffeine depletes the normal calcium gradient below a basal level of 150 nM, a tip focused elevation in cytoplasmic calcium occurs.  Following removal of caffeine, cells recover their tip focused calcium gradient and continue elongating, but the streaming pattern does not fully recover.

Figure 6: When lanthanum blocks calcium channels at the tiip, the cytoplasmic calcium gradient is lost.  Following removal of lanthanum, the gradient recovers.  About 10-15 minutes after recovery, organelles switch direction and move in a reverse fountain pattern.

Figure 7:  Verapamil causes a rapid accumulation of vesicles at the tip as motility stops.  Following removal of verapamil, the cytoplasm reorganizes and streaming resumes.