F. Deng, S.W. Zhu, L.J. Wu,B.J. Cheng
Published April 27, 2010
Genet. Mol. Res. 9 (2): 785-796 (2010)
DOI 10.4238/vol9-2gmr768
About the Authors
F. Deng, S.W. Zhu, L.J. Wu,B.J. Cheng
Corresponding author
B. Cheng
Email: beijiucheng@ahau.edu.cn
ABSTRACT
The relationship between pollen germination and the dynamic organization of the actin cytoskeleton during pollen germination is a central theme in plant reproductive biology research. Maize (Zea mays) pollen grains were implanted with 30 keV argon ion (Ar+) beams at doses ranging from 0.78 × 1015 to 13 × 1015 ions/cm2 . The effects of low-energy ion implantation on pollen germination viability and the dynamic organization of the actin cytoskeleton during pollen germination were studied using confocal laser scanning microscopy. Maize pollen germination rate increased remarkably with Ar+ dose, in the range from 3.9 × 1015 to 6.5 × 1015 ions/cm2 ; the germination rate peaked at an Ar+ dose of 5.2 × 1015 ions/cm2 . When the implantation dose exceeded 7.8 × 1015 ions/cm2 , the rate of pollen germination decreased sharply. The actin filaments assembled in pollen grains implanted with 5.2 × 1015 ions/cm2 Ar+ much earlier than in controls. The actin filaments organized as longer parallel bundles and extended into the emerging pollen tube in treated pollen grains, while they formed random and loose fine bundles and were gathered at the pollen aperture in the control. The reorganization of actin cytoskeleton in the pollen implanted with 9.1 × 1015 ions/cm2 Ar+ was slower than in controls. There was a positive correlation between pollen germination and the dynamic organization of the actin cytoskeleton during pollen germination. Ion implantation into pollen did not cause changes in the polarization of actin filaments and organelle dynamics in the pollen tubes. The effects of Ar+ implantation on pollen germination could be mediated by changes in the polymerization and rearrangement of actin polymers.
Key words: Maize pollen, Low-energy ion implantation,Pollen germination, Actin cytoskeleton.