Blue, red and blue plus red light control of chloroplast pigment and pigment‐proteins in corn mesophyll cells: Irradiance level‐quality interaction

Corn (Zea mays L. cv. OP Golden Bantum) was grown under low irradiance blue, red or blue plus red light. Red was more effective than blue light for synthesis of Chl a, b and light‐harvesting proteins (LHC‐2) associated with photosystem 2(PS2). Blue light was slightly more effective for synthesis of light‐harvesting proteins (LHC‐1) associated with photosystem 1 (PS1), but below a fluence rate of 1 μmol m−2 s−1 the response to blue vs that to red depended on irradiance level. Blue light containing a small amount of red light was as effective as red light for Chl a and b synthesis, but no more effective than blue light for LHC‐2 synthesis. Adding small amounts of blue light to red repressed the effect of red light on LHC‐2 synthesis and produced irradiance response curves similar to those produced by blue alone for LHC‐2 synthesis. This repression by blue light depended on the ratio of red to blue and the level of the blue light.