Photosynthetic Adaptation to Light Intensity in Leaves of Acer pseudoplatanus

Some preliminary experiments on light adaptation phenomena in Acer pseudoplatanus L. (sycamore) are described. First year seedlings were grown under four different light intensities. The light intensity dependence of photosynthesis, and the relation between exposition light intensity and both chlorophyll content and protein content were measured on single leaves. 1. It appeared from the photosynthesis curves that, with increasing exposition light intensity, the saturation light intensity as well as the maximum rate of photosynthesis, increases. 2. The chlorophyll content/cm2 decreases with increasing exposition light intensity. 3. Within each light intensity class, the maximum rate of photosynthesis seems to be directly correlated with the chlorophyll content. 4. In strong light, the leaves are thicker, however, without conspicuous increase in protein content.