Increase in function during growth of a single cell organelle.

The gradient diver method has been adapted to measure photosynthesis during the early development of a single zygote of the multicellular green alga Ulva mutabilis Føyn. The cells have only one chloroplast, and the results indicate that during growth of the chloroplast the rate of O(2)-production increases linearly in the early part of the cell cycle but remains constant or decreases at the end of the cycle.