Summary
To study effects of light quality on the growth of plants, lettuce and spinach were grown for 15 days by water culture in the growth cabinet in which white, red, yellow, green and blue lamps were used as artificial light sources and two levels of light intensities were maintained at 250 and 125 μmol¥m-2¥s-1 in photosynthetic photon flux density(PPFD).HomePage
When lettuce were grown under high light intensity, leaf burning occurred under green light 3 to 4 days after treatment. Spinach, however, did not show such a injury. Both crops grown under red and yellow light showed downward curling of the leaf lamina until 5 to 6 days after treatment. The top dry weight of lettuce plant grown under yellow, green and blue light of high or low light intensity was 20 to 30% lower than that grown under white. Under high light intensity, tops dry weight of spinach under white and red light was highest and that under green light was lowest. Under low light intensity, 50 to 10% less top dry weight was obtained under yellow, green and blue light compared with white light.
Are'a, transpiration, RGR, NAR and SLA of leaves were also affected with light quality. Effects of light quality, however, were different in light intensity and/or vegetable plants. The relations between plant grown and light quality were discussed in the report.Keywords: light quality, lettuce, spinach, water culture, growth, leaf area, leaf injury, transpiration, chlorophyll, assimilation rate