Public release date: 12-Dec-2011
http://www.eurekalert.org/pub_releases/2011-12/asfh-bli121211.php

American Society for Horticultural Science

Treated seedlings are healthier, more vigorous after transplanting

ABIKO, JAPAN—The quality of agricultural seedlings is important to crop growth and yield after transplantation. Good quality seedlings exhibit characteristics such as thick stems, thick leaves, dark green leaves, and large white roots. Scientists have long known that plant development and physiology are strongly influenced by the light spectrum, which affects seedling structure. Raising seedlings irradiated with blue light has been shown to increase crop yield after planting because of the high accumulation of phenolic compounds. Although most studies with blue light only or blue mixed with red light have indicated that blue light-containing irradiation produces higher plant biomass, recent research has suggested that yield and crop quality could be improved by controlling light quality.

Researchers from Japan's Central Research Institute of Electric Power Industry premiered a study in HortScience that determined the effects of raising seedlings with different light spectra—such as with blue, red, and blue + red LED lights—on seedling quality and yield of red leaf lettuce plants. Photosynthetic pigments, polyphenols, and antioxidant activity of lettuce seedlings treated with different light spectra were also determined.