Leaf Photosynthetic Rate, Growth, and Morphology of Lettuce under Different Fractions of Red, Blue, and Green Light from Light-Emitting Diodes (LEDs)

• Published in: Horticulture, environment and biotechnology pp. 574 - 580
• Main Authors: 강우현, 박종석, 박경섭, 손정익
• Format: Journal Article
• Language: English
• Published: 한국원예학회 01.12.2016
• Subjects: 농학
• ISSN: 2211-3452; 2211-3460

Current LED-based artificial lights for crop cultivation consist of red and blue lights because these spectra effectively promote leaf photosynthesis. However, the absence of green light could be disadvantageous for crop production, as green light plays an important role in plant development. The objective of this study was to investigate whether adding green light to different proportions of red and blue light would affect the leaf photosynthetic rate, growth, and morphology of lettuce plants. Plants were transplanted and grown hydroponically for 25 days under different combinations of red, blue (0, 10, 20, and 30%), and green (0 and 10%) light at 150 ± 15 μmol･m-2･s-1 of photosynthetic photon flux density (PPFD). The leaf photosynthetic rate was highest under 80% red and 20% blue light and decreased significantly with the addition of green light and the absence of blue light. As the fraction of blue light increased, leaf size and plant growth decreased significantly. However, while the addition of green light considerably reduced the leaf photosynthetic rate, it did not reduce plant growth. In the absence of blue light, the plants showed symptoms of the shade avoidance response, which possibly enhanced their growth by improving their light interception. Therefore, the addition of 10% (15 μmol･m-2･s-1) green light did not have a positive effect on the growth of lettuce. Further study using higher intensities of green light is required to investigate the effects of green light on plant growth. KCI Citation Count: 18