Fluctuations in the pollen tube tip-focused calcium gradient are not reflected in nuclear calcium level: a comparative analysis using recombinant yellow cameleon calcium reporter
- First Online:
- Cite this article as:
- Watahiki, M.K., Trewavas, A.J. & Parton, R.M. Sex Plant Reprod (2004) 17: 125. doi:10.1007/s00497-004-0224-x
- 125 Downloads
For the first time in pollen tubes, both cytoplasmic and nuclear calcium have been imaged to allow comparative analysis of calcium dynamics in these two compartments with high spatial and temporal dynamics. An improved cameleon (YC2.1) calcium reporter was expressed cytoplasmically in both Lilium longiflorum and Nicotiana tabacum pollen tubes and the periodically fluctuating tip-focused calcium gradient typical of normal growth was recorded by ratio image analysis. The nucleoplasmin targeting sequence was then used to localise expressed YC2.1 to the vegetative nucleus of N. tabacum pollen tubes to permit imaging of nuclear location, shape and calcium dynamics. Nuclear-targeted YC2.1 (NupYC2.1) showed an absence of any obvious regular fluctuations in nuclear calcium levels during tube extension in vitro with typical growth rate fluctuation. The use of targeted cameleons to study subcellular calcium dynamics in pollen tubes is discussed.