关键词: 植物工厂, LED, 红蓝光, ICP-AES, 营养元素, 生菜

Abstract: In this study, the effects of white vs. red/blue LED light of different intensity on the growth and nutrient element content as well as accumulation of hydroponic lettuce were studied using ICP-AES analysis technology in a closed plant factory. White light (WL) and the combination of red and blue light (RB) at different intensities including 150（WL150, RB150）, 200（WL200, RB200）, 250（WL250, RB250）μmol·m^-2·s^-1 were conducted in the experiment. Red/blue ratio was 4∶1, and photoperiod was 16/8 h. The results showed that both shoot fresh weight and shoot dry weight increased with the increase of light intensity. And the shoot dry weight under WL200 and WL250 was 24.6% and 49.7% higher than that of WL150, respectively. Compared with RB, WL significantly increased leaf area and biomass of lettuce. RB increased the contents of large and medium elements (N, P, Ca, Mg) and trace elements (Mn, Zn) in lettuce leaves, while WL increased K content. Light quality had no significant effect on C, Fe and Cu contents. The content of nutrient elements in lettuce had no obvious regularity response to light intensity under WL or RB. The contents of various nutrient elements (N, P, Ca, Mg, Mn, Cu, and Zn) were the highest at 200 μmol·m^-2·s^-1 under red and blue light. Under WL, the accumulations of P, K, Ca, Mg, Fe, Mn, Cu, and Zn were the highest at 200 μmol·m^-2·s^-1, while the accumulations of ten nutrient elements were the highest at 250 μmol·m^-2·s^-1 under RB. Under the same light intensity, RB was beneficial for the increase of N, P, Ca, Mg, Mn, and Zn contents in lettuce, while WL was more conducive for the accumulations of N, C, P, K, Mg, and Fe. In conclusion, WL could promote the growth of lettuce and increase the accumulation of N, C, P, K, Mg, and Fe in lettuce, which was mainly determined by higher biomass.

Key words: plant factory, LED, red and blue light, ICP-AES, nutrient elements, lettuce