SPECTRAL ENGINEERING OF PLANT METABOLISM IN CONTROLLED ENVIRONMENT AGRICULTURE: MECHANISMS, METABOLIC REPROGRAMMING, AND PRECISION LIGHTING STRATEGIES

Abstract

Controlled environment agriculture (CEA) is a promising solution to sustainable crop production under growing pressure from climate change, urbanisation and resource constraints. One of the key technological advances in CEA is the application of spectral engineering with programmable light-emitting diode (LED) systems to precisely control plant growth, metabolism, morphology and nutritional quality. The present review critically evaluates the role of spectral environments in modulating plant physiological and biochemical processes with special emphasis on photosynthesis, carbon and nitrogen metabolism, antioxidant responses, secondary metabolite biosynthesis and crop-specific quality parameters. The review discusses the use of dynamic lighting strategies, spectral-spatial optimisation and pre-harvest illumination approaches to boost productivity and phytochemical accumulation in horticultural crops and recent advances in integrating metabolomics, transcriptomics, high-throughput phenotyping, artificial intelligence, deep learning, and digital twin technologies in the context of intelligent environmental control and predictive cultivation systems. Furthermore, current challenges regarding energy consumption, economic feasibility, reproducibility and large-scale implementation of plant factory systems with artificial lighting are critically analysed. The results show that effective spectral engineering demands crop and growth stage specific spectral recipes, rather than universal ones. Further integration of photobiology, computational modelling, smart sensing systems and sustainable energy management will be key to future progress in CEA and to generate adaptive cultivation systems that can improve yield, nutritional quality, stress resilience and resource-use efficiency concurrently. In brief, spectral engineering is a developing multidisciplinary field with great promise for advancing sustainable and intelligent indoor agriculture.