## 1 Introduction
The light spectrum can, both directly and indirectly, impact photosynthesis by modulating leaf structure, size, senescence rate, photosynthate transport, stomatal conductance, transpiration, gas exchange, chlorophyll content, plant height, stomatal opening, circadian rhythm, photomorphogenesis, flowering time, and chlorophyll biosynthesis [9]. Extensive research has elucidated the impact of light cycles and environmental conditions on plant development from germination to senescence, with numerous studies examining the correlation between photoperiod and flowering patterns across different plant families by regulating flowering-induced genes [10; 11]. Light stands as a pivotal environmental factor for plant growth and development, with stressfulconditions capable of inducing the excessive production of reactive oxygen species (ROS) (Figure 1) [12; 13]. ROS can wreak havoc on cellular components, including carbohydrates, lipids, proteins, and DNA, potentially leading to plant death. To combat this onslaught, plants deploy a sophisticated arsenal of enzymatic and non-enzymatic antioxidants to regulate ROS production [14]. Figure 1: The figure illustrates the intricate effects of light quality, intensity, and photoperiod on the growth, development, and metabolic pathways of cannabis plants. Light, in terms of quality,  
intensity, and photoperiod, is perceived by photoreceptors, which subsequently trigger transcription factors (TFs) that regulate gene expression related to growth and development. The use of LED lights provides controlled light spectra that influence various physiological responses. Optimal wavelengths significantly impact photomorphogenesis and shade avoidance mechanisms, primarily by regulating auxin transport and signaling. The circadian clock also plays a role in coordinating growth, hormone signaling, and metabolic processes in response to light cycles. Optimal light conditions enhance photosynthesis efficiency by increasing CO\({}_{2}\) and H\({}_{2}\)O uptake, while also promoting osmotic adjustment and strengthening the plant's defense against reactive oxygen species (ROS) through the upregulation of detoxification enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), and glutathione \(S\)-transferase (GST). These changes, collectively contribute to vigorous plant growth, increased inflorescence size, and the development of glandular trichomes, which are important for secondary metabolite production. The plant's hormonal responses, including auxin (IAA), cytokinin (CK), abscisic acid (ABA), gibberellin (GA3), salicylic acid (SA), and jasmonic acid (JA), are also regulated by light and play a critical role in growth and stress responses. In addition to light's direct effects on plant physiology, the figure highlights the symbiotic relationship between cannabis plants and microbes, which can further enhance plant health and nutrient acquisition. The top-right section emphasizes the impact of different light spectra on plant responses, affecting metabolic pathways and cannabinoid production. The detailed metabolic pathways in the bottom-right panel depict the biosynthesis of cannabinoids and terpenoids. Key precursors such as acetyl CoA, pyruvate, and fatty acids enter the Pakistani MEP and cytoplasmic MVA pathways to produce isopentenyl pyrophosphate (IPP) and geranyl pyrophosphate (GPP), leading to the synthesis of primary cannabinoids like Cannabigerolic acid (CBGA). CBGA serves as a precursor for tetra-hydrocannabinolic acid (THCA), cannabididic acid (CBDA), and cannabichromenic acid (CBCA). The terpenoid biosynthesis pathway illustrates how intermediates like GPP and farnesyl pyrophosphate (FPP) are converted into terpenoids, including \(\beta\)-mycrene, limonene, \(\beta\)-caryophyllene, \(\beta\)-amyrin, and squalene. Additionally, the phenylpropanol pathway shows the synthesis of phenolic compounds such as Cannflavin A and apigenin from phenylalanine-derived intermediates like p-coumaroyl-CoA and feruolyl-CoA.