Abstract
To investigate the effect of different light conditions on the antioxidative activities of suspension-cultured tea (Camellia sinensis L. cv. ‘Yabukita’) cells, we measured the growth, ascorbate (AsA) content and lipid peroxidation of suspension-cultured tea cells grown under continuously illuminating condition with red (light-emitting diodes) LEDs (650-670 nm), blue LEDs (450-470 nm), red LEDs with supplemental blue LEDs (red plus blue LEDs) or white fluorescent lamp with 100 μmol m-2 s-1 of photosynthetic photon flux density for 7 days, comparing with ones grown under dark. The cell growth in all light-treated conditions has decreased to the half in the dark condition, and the lipid peroxidation has increased. The content of AsA in tea cells was increased in blue LEDs, red plus blue LEDs and white fluorescent light treatments. Oxalate contents of red plus blue LEDs and white light treatments were higher than that of other treatments. On the other hand, the catalase activity was decreased in light conditions including the blue wavelength band, whereas the ascorbate peroxidase activity did not change in any treatment conditions. Furthermore, superoxide dismutase activity was only decreased in red LEDs and red plus blue LEDs conditions. These results suggested that the blue light wavelength might be induced AsA synthesis directly or through the suppression of catalase activity in cultured tea cells.
