Fl10blb

Based on the previous research, we have known that blue light and UV-A light spectra were effect to accumulate anthocyanin in sunlight [16 (link)]. Then seeds of the turnip Brassica rapa L. subsp. rapa cv. Tsuda were sown in a row on wet filter paper and grown in the dark at 25 °C for 3 days, then irradiated with blue light (470 nm light-emitting diode LED, NSPB5205, Nichia, Tokushima, Japan) at 10 W m-2 or UV-A light (UV-A fluorescent lamp, FL10BLB, Toshiba, Japan, filtered through soda-lime glass plates, peak at 350 nm) at 3 W m-2 for 24 h. For the control group, the seedlings were still grown in the dark. Then light treated and dark-grown seedlings were used as materials for RNA isolation and real-time PCR. For anthocyanin measurements and cross-section analysis, the seedlings grew in sunlight or darkness for four days separately.

Seeds of the turnip Brassica rapa L. subsp. rapa cv. Tsuda which originated from Dr. Kawabata Saneyuki’s laboratory (University of Tokyo) were sown in a row on wet filter paper. The seedlings were grown in the dark at 25 °C for 3 days until they were approximately 4 cm tall. For light treatments, these dark-grown seedlings were then irradiated with blue light (470 nm light-emitting diode LED, NSPB5205, Nichia) at 10 W m⁻² or UV-A light (UV-A fluorescent lamp, FL10BLB, Toshiba, filtered through soda-lime glass plates, peak at 350 nm) at 3 W m⁻² for 24 h. For the dark control, seedlings were grown in the dark. After a 24-h irradiation, whole seedlings (ground parts and roots) were collected and ground in liquid nitrogen to isolate total RNA using TRNzol-A⁺ reagent according to the manufacturer’s instructions (TIANGEN, Biotech, Beijing, China). Anthocyanin was estimated as described previously [23 (link)] by calculating the ratio of OD₅₃₀ to gram fresh mass.