EFFECT OF LED (LIGHT EMITTING DIODE) LIGHT ON THE GROWTH OF RED CURLY CHILI PLANTS (CAPSICUM ANNUUM VAR. LADO)

• Main Author: Zaina Nabila, Raiza
• Format: Final Project
• Language: Indonesia
• Subjects: Ilmu hayati ; Biologi
• Online Access: https://digilib.itb.ac.id/gdl/view/85712
• Institution: Institut Teknologi Bandung

Curly red chili pepper (Capsicum annuum L. var. Lado) is a popular horticultural crop in Indonesia, but the production fluctuates due to pests and climatic conditions. Indoor cultivation using LED lights is a potential solution to improve chili productivity. LED lighting can influence growth, flowering, and secondary metabolites, with varying effects on different species and cultivars. This study aimed to determine the effects of red, blue:red (1:1), blue:red (3:1), blue, white LED lighting, and sunlight as control on the vegetative and generative growth, and the secondary metabolite content of curly red chili peppers. Chili seeds were sown and grown under treatment conditions until they developed four leaves with a photoperiod of 12 hours of light. The seedlings were then transferred to a growing medium composed of cocopeat. In one light treatment, there were 4 seedlings sown under natural light and 4 seedlings sown under the treatment light condition. Vegetative data included germination rate and seedling height measured 21 days after sowing, as well as plant height, number of leaves, and number of branches recorded weekly for 16 weeks after planting. Stomatal density was observed under a Scanning Electron Microscope (SEM). Generative data included the time of flower initiation, number of flowers, fruit set percentage, number of fruits, fruit length, and fruit weight. Secondary metabolite data included chlorophyll a and b concentrations in the leaves analyzed using SPAD, capsaicin concentration analyzed using HPLC, ?-Carotene concentration measured with a UV/VIS spectrophotometer, and antioxidant activity (IC50) in the fruit using the DPPH (2,2-diphenyl-1-picrylhydrazyl) method. The results showed that LED light had no significant effect on germination rate. Red light treatment significantly increased seedling height. For vegetative growth, white light provided the best results for plant height, number of leaves, stomatal density (133,057 stomata/mm²), and number of branches. Moreover, white light also produced the best results for flowering time (5th week after planting), number of flowers (108 ± 35 flowers/plant), fruit set percentage (30.6 ± 13.07%), number of fruits (17 ± 6 fruits), fruit weight (2.56 ± 0.32 g), and fruit length (10.81 ± 0.3 cm). In terms of secondary metabolite content, white light resulted in the highest chlorophyll concentration (3.80 ± 0.38 mg/g FW), while the highest chlorophyll a to b ratio (1.92 ± 0.01) was found in the red light treatment. Additionally, white light produced the highest antioxidant activity, indicated by the lowest IC50 value (1351 ± 482.3 ?g/mL). Blue light significantly increased capsaicin content (0.91 ± 0.15 mg/g FW). Lastly, LED lighting had no significant effect on ?-Carotene concentration. Based on these findings, it can be concluded that the best vegetative and generative growth of curly red chili pepper occurs under white light treatment, while blue light treatment can enhance capsaicin content in the fruit.