Reactive oxygen species influence the growth properties of pollen tubes. They influence the intracellular messenger Calcium as well. With the help of fluorescenct Calcium-sensing proteins and a confocal microscope the cellular concentration of Calcium can be visualized in living pollen tubes. At the tip of growing pollen tubes of wild type there seems to be a continuous Calcium influx (red staining on the left upper part). Without reactive oxygen species the picture is totally different: not only the growth of the pollen tube is discontinuous but also the influx of Calcium at the tip fluctuates strongly (on the right upper part).
Image Credit: Roman Lassig