Photosynthesis in the Pericarp of Developing Wheat Grains

Oxygen exchange in grains of wheat was measured in both light and dark over the period of grain development. Between 10 d and 30 d after anthesis, the rate of photosynthesis exceeded the rate of respiration. Peak photosynthetic activity was observed at 20 d after anthesis, coinciding with maximum chlorophyll content in the pericarp green layer. Removal of the pericarp transparent layer increased rates of oxygen exchange in both the light and the dark. Attempts to inhibit photosynthesis with DCMU were only successful with the pericarp transparent layer removed.