| Summary: | 碩士 === 國立屏東科技大學 === 生物機電工程系所 === 104 === The Lollo Rosso lettuce(Lactuca sativa) contains high ascorbic acid, total phenol, and anthocyanin. However, the roof covering materials will result in insufficient light and filtering ultraviolet light for lettuce growth in greenhouse and reduce lettuce yield and quality. This study propsed a supplemental LED lighting method using different single narrowband wavelengths to irradiate lettuce at night, respectively. The self-designed hydroponic and environmental control facilities were installed in a greenhouse to meet lettuce growth condition. The experimental site was located on the roof of the Department of Biomechatronics Engineering building, National Pingtung University of Science and Technology (E 120°36'25.038" N 22°38'52.8576). Two experiments were performed and each of them had control group (without supplemental light case), while test group included four monochromatic light irradiation treatments which were, red (655 nm), blue (445 nm), green (525 nm), and ultra UV (380 nm), respectively. The lighting intensity of each monochromatic irradiation was 150μmol．m-2．s-1 except for UV light (20μmol．m-2．s-1). The growth analysis of lettuce included, fresh weight shoot, leaf, stem, and root, leaf number, leaf area, maximum leaf width, average leaf width, maximum leaf length, relative chlorophyll value (SPAD), relative anthocyanin value (ACI), nitrate content, leaf color analysis, and cost-effecitve. The first experiment results demonstrated that the maximum shoot fresh weight was obtained under blue light irradiation treatment. The hightest anthocyanin ACI value was obtained under red light treatment. The second experiment results showed that the use of red light, UV light and without supplemental light irradiation had higher SPAD value in constrast to green light irradiation. Regarding color analysis, blue light treatment got higher green level than green light iridation treatment. As for cost-performance (CP) analysis, the highest CP value was acquired through red light treatment under both experiments. Therefore, the use of red light irridation for lettuce at night was more benefit for lettuce growth and can obtain better leaf fresh weight, content of anthocyanin, and CP ratio in contrast to other treatments.
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