Plant architecture manipulation increases cannabinoid standardization in ‘drug-type’ medical cannabis

Abstract

A major challenge in utilizing cannabis (Cannabis sativa L.) for modern medicine is the lack of standardization throughout the plant of cannabinoids, the unique therapeutic secondary metabolites in cannabis. The present study focused on the interplay between plant architecture modulation and standardization of the secondary metabolite profile in medical cannabis plants. Secondary metabolism is considerably affected by endogenous and exogenous factors, including positional-developmental aspects and microclimate. We hypothesized that manipulation of the plant architecture, which alter morphological and reproductive development, as well as micro-climate in the shoot will impact secondary metabolism and spatial standardization of the cannabinoids. Eight plant architecture-modulation treatments were evaluated for effects on in-planta concentrations and standardization of the cannabinoids, and on the morpho-physiological state of the plants. Two medical-cannabis genotypes of 'drug-type' medical cannabis were analyzed to evaluate genotypic sensitivity. The results reveal that plant architecture modulation can increase standardization of the cannabinoid profile in cannabis, thereby supporting the hypothesis. The architectural modulating treatments increased uniformity of cannabinoid concentrations in the plant by increasing concentrations at the lower parts of the plant. The cannabinoid profile was most affected by treatments that had the largest impact on plant structure such as the removal of primary and secondary branches. Decarboxylation of the cannabinoids in-planta was not affected by structural modulation. The spatial uniformity of cannabinoid concentrations throughout the cannabis plant is cannabinoid and genotype specific, and the effect of architecture modulation on cannabinoid standardization is genotype specific.