Figure 5.

Appearance of a red perilla leaf at the 5th node counted from the bottom of the main stem 2 weeks after treatment initiation (Experiment 2). Perilla plants were irradiated for 3 h from 02:00 to 05:00 h in a UV-B light treatment regimen. The UV-B radiation intensity at the plant canopy level was set to 0.05, 0.1, or 0.2 W m⁻². The integrated UV-B energy at 0.05, 0.1, and 0.2 W m⁻² was 0.54, 1.0, and 2.2 kJ m⁻² day⁻¹, respectively. Leaves at the 5th node counted from the bottom of the main stem were harvested 2 weeks after treatment initiation. Leaf blade length under the control, 0.05 W, 0.1 W, and 0.2 W treatment conditions was 11.4 ± 0.8, 11.3 ± 0.4, 9.5 ± 0.4, and 7.1 ± 0.7 cm, respectively (mean ± SE, n = 4). Each white bar indicates 5 cm.