Photosynthesis of wheat under field conditions. I. The interaction of photosynthetic organs

Abstract

Four wheat varieties were examined to determine differences of grain production in response to ear shading and defoliation treatments under field conditions. Responses to both ear shading and defoliation were affected by the level of competition and by the number of tillers on the plants. There was a movement of assimilates between shoots.

Compensation, in production of assimilate by other organs, was very pronounced when parts of the plant were shaded or leaves removed. "Sink" size appears to be an important factor in the supply of carbohydrate to the grain. The nitrogen content of the grain was not affected by ear shading.