Abstract
Polarity patterning of pollen germination is a vital process for angiosperm fertilization. In our study a new method was employed to investigate the real-time distribution of calmodulin (CaM) in living pollen grains and pollen tubes. The CaMGFP fusion gene was constructed under the control of the pollen-specific promoter LAT52-7 and transformed into Nicotiana tabacum L. Through confocal laser scanning microscopy, high levels of CaM were observed to accumulate in the three germinal apertures, and a tipbase gradient of CaM was detected in elongating pollen tubes. During pollen-grain hydration and germination, one of the three germinal apertures aggregated a much higher level of CaM than the other two. In addition, CaM showed a directional migration from the cytoplasm to this germinal aperture, where the pollen tube would emerge. Interestingly, CaM was not detected in the reproductive nucleus of either pollen grains or pollen tubes. Our findings indicated that the directional migration of CaM existed during pollen hydration and germination, and this movement may play a crucial role in the normal polarity establishment of pollen germination.Key words: calmodulin, polarity, pollen grain, Nicotiana tabacum.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have