Effect of Light Quality on Cannabinoid Content of Cannabis sativa L. (Cannabaceae)

Abstract

Plants of a drug strain of Cannabis sativa L -grown 33 days under daylight, shaded daylight conditions, filtered green, blue, and red light, and darkness-were analyzed by gas-liquid chromatography for their cannabinoid content. The highest content of cannabinoids, predominantly Δ9-tetrahydrocannabinol (Δ9-THC) in this strain, occurred in the youngest leaves of daylight-grown plants Leaves at successively lower nodes of this control condition and all treated plants subsequently grown in daylight contained progressively lower levels of cannabinoids Leaves from plants grown under filtered green light and darkness contained significantly lower levels of Δ9-THC than those from plants grown in daylight However, the Δ9-THC content of leaves from plants grown under shaded daylight and filtered red and blue light did not differ significantly from the Δ9-THC content in daylight controls, indicating that these conditions did not alter the synthetic rate of this cannabinoid The cannabichromene (CBC) content of plants...