Effect of LED supplemental lighting system on the growth of pea shoots

Effect of LED supplemental lighting system on the growth of pea shoots is presented. The dominant wavelengths of 454 nm and 655 nm LEDs were used as light sources and the fluorescent was taken as the comparison. The continuous dimming was used for LED supplementary lighting control system to design three different luminous intensity environments in order to explore the influence of different red to blue light (R/B) ratios and photosynthetic photon flux density (PPFD) distributions on the growth of pea shoots. The fresh weights and chlorophyll contents were measured for each group after 10 days under the same photoperiod. The result shows that pea shoots under LEDs grow better than those under fluorescent and three LED groups on average consume almost 47.66% less energy than the fluorescent group, which shows the remarkable advantages and bright prospect of LED supplementary lighting system. The result also indicates that pea shoots under different R/B ratios do not have significant difference in fresh weight and chlorophyll content while the pea shoots under relatively low PPFD (62–87µmol/m 2 s) grows better than those under relatively high PPFD (87–112µmol/m 2 s), which means that relatively low PPFD is beneficial to increase fresh weight and promote the photosynthesis of pea shoots.