A Portrait Under Ultraviolet: Physiological and Biochemical Responses in Medicinal Cannabis

Cannabis sativa L. is a plant producing health-affecting specialized metabolites including terpenoids, cannabinoids, and flavonoids. Terpenoids and cannabinoids are abundantly produced in cannabis flowers, whereas flavonoids accumulate in both flowers and leaves. Light is of paramount relevance because it is the major driver of photosynthesis and thus influences growth, morphology, and specialized metabolism. Light spectrum has been used to modulate specialized metabolism via photoreceptor signaling involved in the regulation of the biosynthesis of specialized metabolites. In medicinal cannabis cultivation, UV is used to potentially enhance the production of terpenoids, cannabinoids, and flavonoids in leaves and inflorescences, though underlying mechanism are poorly understood. Therefore, this thesis evaluates the effect of different UV spectra and doses in medicinal cannabis growth, morphology, physiology, and specialized metabolism. It is concluded that UVB strongly stimulates pigments, sesquiterpenoids, and flavonoids accumulation and profiles. UVB application in medicinal cannabis cultivation poses a useful horticultural strategy to increase floral quality by enhancing the production of glycosylated flavonoids.