EFFECT OF APPLICATION OF DARK PERIOD PROLONGATION USING BLUE-RED LIGHT COMBINATION ON MICROGREEN KALE (BRASSICA OLERACEA VAR. ACEPHALA) GROWTH AND POLYPHENOL COMPOUNDS CONCENTRATION IN CONTROLLED ENVIRONMENT

• Main Author: Nur Azmi Rahmadian, Fatimah
• Format: Final Project
• Language: Indonesia
• Subjects: Ilmu hayati ; Biologi
• Online Access: https://digilib.itb.ac.id/gdl/view/79284
• Institution: Institut Teknologi Bandung

Energy efficiency in indoor farming systems requires constant improvisation. The application of artificial light such as LEDs in this system has increased production costs and led to larger carbon footprints. Extending the dark period duration in seconds in photoperiods is thought to reduce growth inhibition and potentially increase energy efficiency in the agricultural industry. Because of their short growing time and good nutritional content, microgreens are suitable for indoor production. Microgreens of the Brassica group have a greater variety of polyphenols compared to their mature phase, making them a potential source of antioxidants. This study was conducted to determine the effect of extending the dark period duration using on and off seconds on the growth and levels of polyphenol compounds in microgreens. The plant used in this study was kale microgreens (Brassica oleracea var.acephala) which had been sown in the dark for 3 days. The seedlings were then treated with different dark period durations, with a ratio of light (L): dark (D) for 5:10, 5:20, 5:40, and 5:60 seconds and a control group with a ratio of 10:14 hours using 12 red and 2 blue LED lights respectively. The treatment was carried out for 12 days with a regular water supply. Each test group had 6 samples. To determine the kale's quality of photomorphogenic development, variables of daily height, fresh mass, relative channel brightness, and levels of polyphenol compounds were used. Daily height was measured at 5 points in every test group sample to obtain the average value. Using ImageJ software, daily digital images were also used to obtain the relative channel brightness value that is associated with the colour intensity. Fresh mass and levels of polyphenol compounds were measured after 12 days of treatment. The study showed that there were significant differences in average daily height between the control group and the 5:40 and 5:60 treatments, indicated by a significance value of 0.002 and 0.024 at p<0.05. Based on fresh mass, there was no significant difference between the control and treatment groups with a significance value of 0.061 at p<0.05. The relative value of channel brightness indicated that all test groups showed an RGB pattern similar to that of the control group. The levels of polyphenol compounds in the control and test groups were insignificantly different with a significance value of 0.507 at p<0.05. Therefore, it can be concluded that extending the seconds of the dark period in photoperiods did not significantly affect the growth and content of polyphenol compounds in kale microgreens, indicating the potential of photoperiod engineering to increase energy efficiency in indoor farming systems.