Analisis Jenis Spektrum Cahaya dan Lama Penyinaran Light Emitting Diode (LED) terhadap Pertumbuhan Selada Keriting

Abstract

Light plays a crucial role in plant physiological processes such as photosynthesis, phototropism, and photomorphogenesis. Curly lettuce (Lactuca sativa L.) is a long-day plant requiring more than twelve hours of light for optimal growth. In Indonesia, located near the equator, natural sunlight averages only eleven to twelve hours daily, which may not sufficiently support long-day crops. As an alternative, Light Emitting Diodes (LEDs) offer an energy-efficient light source suitable for hydroponic systems like the Nutrient Film Technique (NFT), where plant roots are continuously exposed to flowing nutrient solutions. This study investigated the effect of LED light spectrum (blue, red, and white) and exposure duration (four, seven, and ten hours) on curly lettuce growth using the NFT method. A true experimental design was used, and data were analyzed through One Way ANOVA. Measured parameters included plant height, leaf number, leaf area, shoot mass, growth rate, and indicators of plant damage (wilted leaves, dry leaves, and mortality). Results showed that E21 (blue light, 4 hours) produced the highest plant height (21.90 cm) and fastest growth rate. E11 (red light, 4 hours) resulted in the highest number of leaves (15.66). The control group (sunlight) yielded the largest leaf area and shoot mass. The most wilted leaves were found in E33, and the most dry leaves in the control group. No plant deaths were observed. In conclusion, both LED light spectrum and exposure duration significantly influenced plant height, leaf number, leaf area, shoot mass, and growth rate. However, they had no significant effect on wilted leaves, dry leaves, or plant mortality.