Study on phytochemical changes of Cannabis sativa L. extract at vegetative growth stage under salinity stress

Environmental stresses such as salinity have a great impact on the amount and quality of secondary metabolites of medicinal plants. To investigate the effect of salinity on phytochemical attributes of cannabis (Cannabis Sativa L.), an experiment in the form of a randomized complete block design with three replications and 5 salinity treatments (0, 2, 4, 6 and 8 dS/m) was conducted in 2019 in medicinal plants research center, Karaj, Iran. In this study, the amount of potassium (K) and sodium (Na) elements and chlorine (Cl) in leaf and root organs of the plant were measured by a flame photometer and colorimetric method, respectively. The content of cannabinoids compounds in leaves including tetrahydrocannabinol (THC), cannabidiol (CBD) and cannabichromene (CBC) were measured by GC/MS. The results showed that there was a significant difference (P≤0.01) among different salinity treatments in terms of Na, K, Cl and cannabinoids THC, CBD and CBC. With increasing salinity level, the amount of Na and Cl ions in leaves and roots increased compared to the control treatment and the highest amount of leaf and root Na (15.81, 14.06 mg/g, respectively) was observed in salinity treatment of 8 dS/m . Also, increasing the salinity concentration caused a decrease in leaf and root K of the plant and the highest amount of leaf and root K (34.83, 34.46 mg / g, respectively) was related to the control treatment. The highest amount of THC and CBD (7.94 and 1.45 mg / g of dried plant, respectively) at salinity concentration of 4 dS / m and the highest amount of CBC at salinity of 2 dS / m (0.012 mg / g dry leaf) were obtained. Therefore, salinity changes the amount of cannabinoids in cannabis and the highest levels of THC, CBD and CBC are obtained at low salinity levels.