Cannabinoid occurrence in seedlings of Cannabis sativa L.: quantitation in seedlings of known age and primary leaf length

Seedlings of a Δ9-tetrahydrocannabinol (THC) dominant strain of Cannabis sativa were employed to develop a biological system to investigate cannabinoid biosynthesis. High-performance liquid chromatography was used to detect and quantify the cannabinoids. Cannabinoids were first detected in seedlings of light/dark-grown plants at 48-50 h. The first cannabinoid detected was cannabichromene (CBC) at 52-54 h. At 60-62 h both cannabigerol (CBG) and THC were detected along with CBC. A similar sequence appeared in dark-grown seedlings, but CBC became evident only at 56-58 h, and THC and CBG were first detected at 66-68 h. This pattern is significant because previously proposed pathways of cannabinoid synthesis have indicated that CBG is a precursor to CBC, yet CBG is not the first cannabinoid to be detected but occurs later with the appearance of THC. Cannabinoid concentrations were always higher in light-grown than in dark-grown plants of comparable age. Cannabinoid quantities on a dry-weight basis increased with increasing leaf length and/or increasing age.