HYPOCOTYL ELONGATION OF LETTUCE AND CHINESE CABBAGE SEEDLINGS EXPOSED TO DIFFERENT LIGHT QUALITIES
Establishment of an effective spectral quality of light is necessary to produce good seedlings without succulent growth. The objective of this study was to examine the effect of different light qualities on hypocotyl elongation of lettuce and Chinese cabbage seedlings. Seedlings were exposed to 13 different qualities of continuous light produced by fluorescent lamps at 22°C. Treatment with light 1 to 13 (L1-L13) were controlled photon flux densities with wavelengths ranging from blue (400-500 nm) to green (500-600 nm) to red (600-700 nm) light. L1 was white, L2 was daylight, L7 was monochromatic blue, and L12 was monochromatic red light. There were significant differences in the daily hypocotyl elongation rate in both lettuce and Chinese cabbage depending on the light quality. Compared to the PPFD, the daily hypocotyl elongation rate in lettuce and Chinese cabbage was positively correlated with the fraction of photon flux density at 640-680 nm and negatively correlated with that at 400-500 nm. Similar correlations were also obtained for top-root ratios of fresh weight. These results indicate that light quality affects hypocotyl elongation and top-root ratio in lettuce and Chinese cabbage. It is suggested that blue light plays an important role in regulating hypocotyl elongation and top-root ratio.
Kasajima, S., Yamada, M. and Inoue, N. (2011). HYPOCOTYL ELONGATION OF LETTUCE AND CHINESE CABBAGE SEEDLINGS EXPOSED TO DIFFERENT LIGHT QUALITIES. Acta Hortic. 907, 175-178
blue light, red light, succulent growth, top-root ratio, vegetable seedling