Artificial lighting, Plant growth, Closed environments, LED technology, Fluorescent lamps, High-pressure sodium lamps, Photosynthesis, Light spectrum, Blue light, Red light, Far-red light, Phytochrome system, Plant development, Hormone production, Energy efficiency, Vertical farming, Microclonal propagation, Controlled environment agriculture, Light intensity, Spectral composition, Sustainable agriculture, Indoor farming, Plant physiology, Photoperiodism.