| Pollen tube growth oscillates in rate. The underlying mechanisms that control oscillatory growth have been unknown. The research for this thesis used pollen tubes of Arabidopsis thaliana as the model material to study the mechanisms. Because of its slow growth rate and small volume, a special device was designed to observe the pollen tube growth and the dynamics of organelles more easily and accurately. Two patterns of Arabidopsis pollen tube oscillatory growth were detected by using this device. One is similar to that of Parton's (2003) report with the growth process oscillateing at the same frequency and amplitude. The average period of this kind oscillatory growth is 24 ?1 s. The other is a new pattern. Other than the periodic oscillation in pollen tube growth rate, the amplitude of each oscillation also changes in an oscillatory behaviour. The amplitude of the growth rate increases from small to large, and then reduces to small. Every complex is composed of 5-6 growth oscillations. We name it "composite oscillation". The average period of the "composite oscillation" is 113 ? s. This is the first time to report this pattern of pollen tube oscillatory growth in plants.Cytosolic free Ca2+ and actin microfilaments play crucial roles in the regulation of pollen tube growth and they may interact with each other. It have been proved that the tip [Ca2+]i and the amount of tip F-actin oscillates periodically accompany the oscillatory growth of pollen tubes. In this study, in order to examine the dynamics of tip [Ca2+]i together with the dynamics of tip-localized F-actin in vivo, a kind of double labeled material was constructed. The Ca2+ and actin microfilaments of Arabidopsis pollen tubes were labeled by cameleon and GFP-mTalin respectively. With these transgenic materials, the relationship between tip [Ca2+]i and tip-localized F-actin in pollen tubes during the oscillatory growth can be well studied.
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