상이한 광질 및 광주기 하에서 UV-A LED 부가 조사가 상추의 생장, 안토시아닌 및 아스코르빈산 함량에 미치는 영향

The growth and contents of anthocyanins and ascorbic acid in lettuce(Lactuca sativa L., 'Jeokchima') as affected by supplemental UV-A LED irradiation under different light quality and photoperiod conditions were analyzed in this study. Five light qualities, namely B (blue LED), R (red LED), BUV (blue LED+UV-A LED), RUV (red LED+UV-A LED) and Control (white fluorescent lamps) with photoperiods of 12/12 hours (day/night), 16/8 hours, or 20/4 hours were provided to investigate the effects of light quality and photoperiod on the growth and accumulation of anthocyanins and ascorbic acid in lettuce leaves. As measured 28 days after transplanting, the number of leaves, leaf length, leaf width, leaf area, shoot fresh weight and dry weight of lettuce were significantly affected by light quality and photoperiod. The number of leaves, leaf length, leaf width, leaf area, shoot fresh weight and dry weight of lettuce grown under R treatment increased with increasing light period. By contrast, leaf development was inhibited, but chlorophyll content increased, under B treatment. Supplemental UV-A irradiation significantly decreased leaf length, leaf width, leaf area and shoot fresh weight. Anthocyanins in lettuce increased significantly with decreasing dark period under B treatment. A synergistic effect of supplemental UV-A LED irradiation on anthocyanins accumulation was found for lettuce leaves grown under R treatment but not B treatment. Ascorbic acid in lettuce was greatly affected by photoperiod. Ascorbic acid content at BUV and RUV treatments increased by 20-30% compared to without UV-A LED irradiation. From these results, it was concluded that growth and contents of anthocyanins and ascorbic acid in lettuce are significantly affected by supplemental UV-A LED irradiation. The results obtained in this study will be informative for efforts to improve the nutritional value of leafy vegetables grown in plant factories. 본 연구의 공시품종은 적치마 상추(Lactuca sativa L., cv. 'Jeokchima')로서 파종 후 본엽이 4매일 때 식물공장 내에 설치된 DFT 재배시스템에 정식하였다. 본 연구에서는 피크파장이 각각 450nm, 660nm, 365nm인 청색 LED, 적색 LED, UV-A LED를 이용하여 청색 LED (B), 적색 LED (R), 청색+UV-A LED (BUV), 적색+UV-A LED (RUV) 등 4개의 처리구를 설정하였고, 대조구로서 3파장 백색형광등을 사용하였다. 또한 광주기(명기/암기)에 따른 효과를 분석하고자 3수준(12/12h, 16/8h, 20/4h)의 광주기를 설정하였다. 식물공장 내 환경 조건은 기온(명기/암기) $22/18^{\circ}C$, 상대습도 70%, $CO_2$ 농도 $800{\mu}mol{\cdot}mol^{-1}$로 조절하였다. 한편 광합성유효광양자속과 UV-A LED의 조사강도는 각각 $230{\pm}11{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, $80{\pm}3mW{\cdot}m^{-2}$이었다. 정식 후 28일째에