Time course of cannabinoid accumulation and chemotype development during the growth of Cannabis sativa L

The time course of cannabinoid accumulation in the leaves of individual plants of three Cannabis accessions was determined by gas-chromatographic analysis in greenhouse-grown plants. The total amounts and the concentration ratios of CBD, THC and CBG were determined; two accessions (an experimental hybrid, (21R × 15R) × NL, and plants from a seized seed lot) were found chemotypically uniform, with all plants belonging to chemotpe II (mixed) and I (high THC) respectively. The Carmagnola accession showed chemotypic heterogeneity, with a majority of plants belonging to chemotype III. The CBD/THC and CBG/CBD ratios were shown to be largely constant in the leaves, since 28 and until 103 days after sowing, and consistent with the ratios determined on mature inflorescences. CBD and THC maximum amounts in the leaves showed a peak in the leaves around 80 days from sowing, and were shown to be simultaneous during the growth period, irrespective of the chemotypes. Callus cultures were obtained from all the five different chemotypes (I, II, III, IV, V), and GC analyses were performed. Independently of the type and amount of cannabinoids in the mother plants, it was confirmed that callus cultures of Cannabis were not able to produce detectable amounts of any cannabinoids.