S08 - Session P4 - Effect of light condition on the growth and lutein and beta-carotene contents in spinach using plant factory with artificial lighting

Authors: Tomo Matsui *, Chihiro Watari, Taihei Oshima, Hiroyuki Watanabe

Recently, it has become possible to cultivate various vegetables by plant factory using artificial lighting (PFAL). Spinach, which is one of the vegetables much expected to be cultivated in PFAL, is known to have a high contents of carotenoids, for example lutein and β-carotene. In the study, we investigated the optimum cultivating conditions for spinach production with the aim of understanding the relationship between lutein and β-carotene contents and growth of spinach by controlling the cultivation environment in PFAL. After 3-week-old spinach plants were cultivated for two weeks under red and blue LEDs (red:blue=1:1) of 150 µmol m -2 s -1 using hydroponic systems. They were cultivated more 1 week under 4 combinations of 2 levels of PPFD (300 or 400 µmol m -2 s -1 ) with two light spectra (only blue and red:blue =1:1). Then the growth and Lutein and β-carotene contents were determined in spinach. There was no significant difference in the shoot fresh weight in any treatment. In the blue light treatment of 300 or 400 µmol m -2 s -1 , the plant height tended to be higher than that in the other treatments. No significant difference was found between 300 and 400 µmol m -2 s -1 of blue light treatments. Therefore, it can be inferred that very little effect can expected for light intensity exceeding 300 µmol m -2 s -1 in spinach. In addition, lutein and β-carotene contents were tended to increase in the blue light of 300 µmol m -2 s -1 treatment. Furthermore, we will show the changes in the expression levels of genes involved in carotenoid synthesis for each light condition in spinach.