형광등이나 LED와 같은 인공광을 사용하는 식물공장(인공광 식물공장)은 계절에 상관없이 광, 온도 및 습도 등을 인위적으로 제어하면서 작물을 안정적으로 연중 생산할 수 있는 시스템이다. 본 연구에서는 수경재배 방식을 채택하고 있는 인공광 식물공장 시스템 내에서 엽채재배용 배양액을 이용한 방풍나물의 수경재배 가능성과 혼합광질이 생장에 미치는 영향을 검토하였다. 방풍나물은 청색과 적색 LED를 1:1 및 1:3의 비율로 혼합한 혼합광 조건에서 90일간 수행하였다. 광원의 광강도는 100 μmol/m2/s로 설정한 후 30일 간격으로 지상부 잎을 3회 수확하여 생장량을 조사하였다. 재배기간 동안 형광등과 LED의 혼합광 조사는 방풍나물 지상부 생장에 유의한 영향을 미치는 것으로 나타났다. 재배개시 30일째 방풍나물 지상부 생체중 및 건물중은 형광등+청색+적색의 혼합광(청, 적색 혼합비율 1:3, FLBR13구)에 의한 영향을 받아, 대조구인 형광등 조사구(FL구)에 비해 각각 3.7배 및 2배 증가하였다. 또한 식물체당 전개엽수는 FLBR13구에서 형광등+청색+적색 혼합광(청, 적색 혼합비율 1:1) 조사구인 FLBR11구에 비해 유의하게 증가하였다. LED와 형광등을 혼합 조사한 처리구에서와 같이, 형광등을 혼합하지 않고 청색과 적색의 LED만을 혼합하여 조사한 처리구에서도 청색과 적색의 혼합비율이 1:1인 BR11구에 비해 적색광의 혼합비율을 3배 증가시킨 BR13구에서 방풍나물의 지상부 생장이 촉진되었다.
BACKGROUND: Plant factory system of an artificial light type using Light-Emitting Diodes (LEDs), fluorescent light, or metal halide lamp instead of sun light is an ultimated method for plant production without any pesticides regardless of seasonal changes. The plant factory is also completely isolated from outside environmental conditions such as a light, temperature, or humidity compared to conventional greenhouse. Light-environment control such as a quality or quantity in the plant factory system is essential for improving the growth and development of plant species. However, there was little report that the effects of various light qualities provided by LEDs on Ledebouriella seseloides growth under the plant factory system. METHODS AND RESULTS: Ledebouriella seseloides seedlings transplanted at urethane sponge were grown in the plant factory system of a horizontal type with LED artificial lights for 90 days. Yamazaki solution for hydroponic culture of the seedlings was regularly irrigated by the deep flow technique (DFT) system on the culture gutters. Electrical Conductivity (EC) and pH of the solution was recorded at 1.4 ds/m and 5.8 in average, respectively during the experimental period. Number of unfolded leaves, leaf length, shoot fresh and dry weight of the seedlings were three times measured in every 30 days after beginning of the experiment. Blue LEDs, red LEDs, and fluorescent lights inside the plant factory were used as light sources. Conventional fluorescent lamps were considered as a control. In all the treatment, light intensity was maintained at 100 μmol/㎡/s on the culture bed. Fresh weight of the seedlings was 3.7 times greater in the treatment with the mixture radiation of fluorescent light and blue+red LEDs (1:3 in energy ratio; Treatment FLBR13) than in fluorescent light treatment (Treatment FL). In FLBR13 treatment, dry weight per seedling was two times greater than in FL or BR11 treatment of blue+red LEDs (1:3 in energy ratio; Treatment BR11) during the culture period. Increasing in number of unfolded leaves was also significantly affected by the FLBR13 treatment comparing with BR11 treatment. CONCLUSION(S): Hydroponic culture of Ledebouriella seseloides seedlings was successfully achieved in the plant factory system with mixture lights of blue, red LEDs and fluorescent lights. Shoot growth of the seedlings was significantly promoted by the FLBR13 with the mixture radiation of fluorescent light, blue, and red LEDs under 1:3 mixture ratio of blue and red LEDs during the experimental period compared to conventional light conditions.