본 연구에서 인공광 이용형 식물공장(plant factories with artificial lighting; PFALs)에서 식물 유래 의약품 소재로서 사용되는 이고들빼기의 안정적인 대량생산 생산을 위한 생산 체계 확립을 위해 일련의 연구들이 수행되었다. 첫 번째, 생장에 적정한 배지의 수분함수율을 확인하기 위해 자동 점적관수 시스템으로 조절되는 20, 30, 45, 60%의 배지수분함량에서 이고들빼기는 5주 동안 재배되었다. 45%의 배지 수분함량은 지상부와 지하부의 생장과 광합성율뿐만 아니라 항산화적 페놀화합물 함량과 총 하이드로시나믹산 함량을 증대시켰다. 또한, 45%의 배지 수분함량을 유지시켜줄 수 있는 심지재배 방식을 통해 이고들빼기의 수경재배화 가능성을 확인하였다. 두 번째, 이고들빼기의 안정적인 생산을 위해 지상부의 미네랄 분석으로 얻은 양이온과 음이온 함량 정보를 기반으로 이고들빼기 전용 배양액(nutrient solution for Crepidiastrum denticulatum; NSC)을 개발하였다. NSC의 적합한 전기전도도(electrical conductivity; EC)를 규명하기 위해 이고들빼기를 다양한 EC 0.5, 1.0, 1.5, 2.0, 2.5dS·m-1에서 6주 동안 재배하였고, NSC의 EC 2.0과 2.5dS·m-1은 지상부 생장과 지상부 전체당 생리활성물질 함량을 증대시켰고 비료의 사용량을 고려하였을 때, EC 2.0 dS·m-1 가장 적합하다고 판단하였다. 세 번째 연구는 PFALs 운영에서 중요한 요소 중에 하나인 광질 조건을 결정하기 위해 수행되었다. 이고들빼기는 적색, 녹색, 청색의 단색광 또는 다양한 혼합광 조건에서 재배되었고 생장과 생리활성물질 함량 변화를 조사하였다. 적색과 청색 혼합광에 녹색광의 추가 조사는 이고들빼기 잎의 광 흡수율을 증가시켜 광합성율을 증대시켰고 광이용효율을 높였다. R8G1B1(R:G:B=80:10:10%)에서 이고들빼기의 생장량과 생리활성물질 함량이 가장 효과적으로 증진되었다. 마지막으로, 생리활성물질을 극대화하기 위해 수확 1주일 전에 다양한 에너지 수준의 UV-B(0, 0.1, 0.25, 0.5, 1.0, 1.25W·m-2)를 일시적으로 하루에 6시간씩 처리해주었다. 처리 4일째, 상대적으로 에너지가 강한 1.0와 1.25W·m-2에서 총 페놀화합물과 항산화도을 증가하였지만, H202 함량도 증가하였고 엽록소가 파괴되어 엽록소 형광 값이 감소하고 잎에서는 가시적인 손상이 나타났다. 반면에 0.25W·m-2의 UV-B 처리는 생장과 엽록소 함량에 부정적인 영향을 주지 않았고, 항산화적 총 페놀화합물과 총 하이드로시나믹산 함량을 증대시켰다. 따라서, PFALs에서 수확 직전 4일 동안 하루에 6시간 0.25W·m-2의 UV-B 처리는 이고들빼기의 효율적인 생리활성물질 생산을 위한 재배시 처리 기술로써 사용될 수 있다. 결론적으로 본 연구를 통해 PFALs에서 식물 유래 의약품 소재로 사용되는 고품질 이고들빼기의 안정적인 대량 생산을 위한 생산 체계를 확립하였다. 이고들빼기 생산 체계의 확립에 사용된 개념은 앞으로 인공광 이용형 식물공장에서 다른 약용작물의 생산에도 적용 가능할 것이다.
We conducted the series of studies to establish the production system for stable mass production of high-quality Crepidiastrum denticulatum used as plant-derived pharmaceuticals in plant factories with artificial lighting (PFALs). First of all, C. denticulatum plants were subjected to four levels of substrate water content (20, 30, 45, and 60%), which were maintained by an automatic irrigation system for 5 weeks, to determine the proper water content of substrate for growth. Not only shoot and root growth and photosynthetic rates, but also antioxidant phenolic and total hydroxycinnamic acids (HCAs) contents of 45% substrate water content were significantly higher than the other treatments at 5 weeks after transplanting. In addition, the capillary wick culture system, which can maintain constant water content of the substrate (45%), verified the availability of hydroponics for C. denticulatum. Second, nutrient solution for C. denticulatum (NSC) was developed based on the cation (K, Ca, and Mg) and anion (N, P, and S) ratios obtained from mineral analysis to ensure the stable and year-round production of C. denticulatum. To determine the proper level of electrical conductivity (EC) of NSC, C. denticulatum was grown under five EC (0.5, 1.0, 1.5, 2.0, and 2.5 dS·m-1) levels of NSC for 6 weeks after transplanting. As a result, the shoot biomass and the content of bioactive compounds per shoot significantly increased in 2.0 and 2.5 dS·m-1 NSC, and 2.0 dS·m-1 NSC was the most appropriate EC considering the use efficient of fertilizer. Third study was conducted to determine the proper light quality condition which is one of important components in terms of management of PFALs. C. denticulatum was grown under monochromatic red (R), green (G), or blue (B) LEDs, or various combinations of RGB and the changes of biomass and bioactive compound content were investigated. The supplemental green light in mixture light of RB LEDs increased photosynthetic rate with increase of light absorbance on C. denticulatum leaves, which resulted in so improvement of light use efficiency of red and blue lights in the RGB group compared to those in RB group. R8G1B1 (R:G:B=80:10:10%) combination was the most effective treatment for increasing shoot biomass and the accumulation of bioactive compounds. Finally, C. denticulatum were subjected to different energy levels of UV-B treatments (0, 0.1, 0.25, 0.5, 1.0, and 1.25 W·m-2) for 6 hours a day for 6 days to maximize the bioactive compounds produced in shoots. At 4 days of UV-B treatment, 1.0 and 1.25 W·m-2 increased antioxidant phenolic content, total hydroxycinnamic acids (HCAs), and H2O2 contents and destroyed chlorophyll pigments, causing the reduction of the maximum quantum efficiency of photosystem II and visible damage to leaves. On the other hand, 0.25 W·m-1 increased antioxidant capacity, total phenolic content, and total HCAs content without the negative effects on the shoot growth and total chlorophyll content. Thus, 0.25 W·m-1 UV-B treatment for 6 hours per day for 4 days before harvest could be used as a cultivation treatment technique for the production of C. denticulatum rich in bioactive compounds in PFALs. In conclusion, we established a production system of high-quality C. denticulatum used as plant-derived pharmaceuticals for stable mass production in PFALs in the series of studies. The concept for establishing of a production system of C. denticulatum can be applied to the production of other medicinal plants in PFALs in the future.
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1. CHAPTER. Literature Review. 11.1. Crepidiastrum denticulatum, a Valuable Native Medicinal Plant. 11.2. Plant Factories with Artificial Lighting for Mass Production of Plant-derived Pharmaceuticals. 31.3. Development of Nutrient Solutions for Hydroponic System. 51.4. Artificial Lighting for Improving the Biomass and Bioactive Compounds of Plants. 61.5. UV-B Radiation for Accumulating Target Bioactive Compounds in Plants. 91.6. Production System of Medicinal Plants in PFALs. 112. CHAPTER. Determination of Adequate Substrate Water Content for Mass Production of a High Value Medicinal Plant, Crepidiastrum denticulatum. 232.1. Abstract. 232.2. Introduction. 252.3. Materials and Methods. 272.4. Results. 332.5. Discussion. 442.6. Conclusion. 482.7. Literature Cited. 493. CHAPTER3. Evaluation of Effects of a Newly Developed Nutrient Solution on Growth, Antioxidants, and Chicoric Acid Contents in Crepidiastrum denticulatum. 543.1. Abstract. 543.2. Introduction. 563.3. Materials and Methods. 583.4. Results. 663.5. Discussion. 763.6. Conclusion. 813.7. Literature Cited. 834. CHAPTER. Manipulation of Light Quality to Promote Shoot Growth and Bioactive Compound Biosynthesis of Crepidiastrum denticulatum in Plant Factories. 874.1. Abstract. 874.2. Introduction. 894.3. Materials and Methods. 924.4. Results. 1014.5. Discussion. 1164.6. Conclusion. 1214.7. Literature Cited. 1235. CHAPTER. Enhancement of Antioxidant Bioactive Compounds of Crepidaistrum denticulatum under Intermittent UV-B Lamp Radiation. 1305.1. Abstract. 1305.2. Introduction. 1325.3. Materials and Methods. 1355.4. Results. 1425.5. Discussion. 1525.6. Conclusion. 1595.7. Literature Cited. 161Appendix Additional Details on Materials and Methods, Results, and Discussion. 170Abstract in Korean. 177Acknowledgement in Korean. 180