Figure 7.

Effect of exposure to intermittent nocturnal lighting for 6 h with UV-B light on leaf fresh weight in red perilla plants (Experiment 3). Perilla plants were irradiated for 1 or 2 h every 1 or 2 h for 6 h, from 18:00 to 06:00. The UV-B radiation intensity at the canopy level was set to 0.05 or 0.1 W m⁻². The integrated UV-B per night at 0.05 and 0.1 W m⁻² was 1.1 and 2.2 kJ m⁻² day⁻¹, respectively. Leaves at the 4th node counted from the bottom of the main stem were harvested 1 week after treatment initiation; thereafter, leaves at the 5th, 6th, and 7th nodes were sampled from the same plants at 2, 3, and 4 weeks after treatment initiation. Vertical bars indicate SE (n = 5). n.s. indicates no significant difference as per the Tukey-Kramer test.