야간 LED 조명이 주요 가로수 묘목의 생리 및 생장에 미치는 영향

초록

The objective of this study was to investigate the effects of prolonged nighttime exposure to decorative light-emitting diode lighting on the physiological responses and growth of seedlings of three tree species commonly used in urban landscaping. Two-year-old grafted seedlings of cherry tree (Prunus yedoensis) and three-year-old seedlings of ginkgo (Ginkgo biloba) and Korean red pine (Pinus densiflora) were subjected to nighttime light-emitting diode (LED) illumination from February 2021 to May 2022. After 18:00 each day, seedlings were exposed to 0 h (control, TC), 6 h (T6), or 12 h (T12) of LED lighting. During the growing period, physiological responses (photosynthetic traits, nighttime respiration, chlorophyll fluorescence, and leaf chlorophyll content), growth parameters (root-collar diameter, seedling height, and dry biomass), and leaf-out timing were measured under different lighting exposures. Across all species, daytime photosynthetic performance, chlorophyll-related traits, and leaf-out phenology did not differ significantly among exposures. In contrast, nighttime respiration in T12 increased after midnight in June relative to the other exposures. After one year of exposure, both root-collar diameter increment and height growth were significantly lower in T12 compared with TC for ginkgo and Korean red pine, whereas there was no significant reduction observed for cherry trees. Total dry biomass was consistently higher in TC compared with the other exposures across all species. Nighttime LED lighting did not markedly affect daytime photosynthesis, chlorophyll-related responses, or leaf-out phenology, but prolonged exposure increased nighttime respiration and was associated with reduced growth in ginkgo and Korean red pine.

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