Light is one of the most important factors affecting corn (Zea mays L.) production. The light saturation point of corn is much higher than that of most other crops, allowing corn to take advantage of the higher light intensity. During the growing season, however, corn frequently encounters low light intensities that restrict growth capacity, therefore limiting the grain yield. The level of photosynthetic active radiation (PAR) can markedly change the growth environment, which directly impacts photosynthesis...