Feedback control of reactive oxygen and Ca signaling during brown algal embryogenesis.

In a recent paper in Planta, we combined novel confocal reflectance imaging of intracellular reactive oxygen species (ROS) with inhibition-of-growth experiments to show that ROS help to direct polarized growth in brown algal zygotes. Using confocal fluorescence imaging of intracellular Ca(2+) distributions, we were also able to show an interaction between ROS and Ca(2+) signaling. The modulation of intracellular Ca(2+) signals by reactive oxygen species (ROS) is a common motif in many plant and algal systems, but our Planta paper is its first demonstration during early development. We explain here how our findings complement a number of recent studies on polarized growth in plant and algal systems.