You are not currently logged in.
Access JSTOR through your library or other institution:
Circular F-actin bundles and a G-actin gradient in pollen and pollen tubes of Lilium davidii
Yan Li, Sze-Yong Zee, Yi-Min Liu, Bing-Quan Huang and Lung-Fei Yen
Vol. 213, No. 5 (September 2001), pp. 722-730
Published by: Springer
Stable URL: http://www.jstor.org/stable/23386393
Page Count: 9
You can always find the topics here!Topics: Actins, Pollen tubes, Pollen, Plant cells, Plants, Endothelial cells, Microfilaments, Antibodies, Cytoplasmic streaming, Corn
Were these topics helpful?See somethings inaccurate? Let us know!
Select the topics that are inaccurate.
Preview not available
The distribution of and relationship between F-actin and G-actin were investigated in pollen grains and pollen tubes of Lilium davidii Duch. using a confocal laser scanning microscope after fluorescence and immunofluorescence labeling. Circular F-actin bundles were found to be the main form of microfilament cytoskeleton in pollen grains and pollen tubes. Consistent with cytoplasmic streaming in pollen tubes, there were no obvious F-actin bundles in the 10- to 20-μm tip region of long pollen tubes, only a few short F-actin fragments. Labeling with fluorescein isothiocyanate (FITC)-DNase I at first established the presence of a tip-focused gradient of intracellular G-actin concentration at the extreme apex of the tube, the concentration of G-actin being about twice as high in the 10- to 20-μm region of the tip as in other regions of the pollen tube. We also found that the distribution of G-actin was related negatively to that of the F-actin in pollen tubes of L. davidii. Caffeine treatment caused the G-actin tip-focused gradient to disappear, and F-actin to extend into the pollen tube tip. Based on these results, we speculate that the circular F-actin bundles may be the track for bidirectional cytoplasmic streaming in pollen tubes, and that in the pollen tube tip most of the F-actin is depolymerized into G-actin, leading to the absence of F-actin bundles in this region.
Planta © 2001 Springer