The effect of ABA on pigments and tetrahydrocannabinol in Cannabis sativa at flowering stage

The effect of ABA was investigated on chlorophyll، carotenoid، anthocyanin and flavonoid content in leaves of male and female cannabis plants at flowering stage. Plants were sprayed with ABA solutions (1 and 10 mg/l) and distilled water as control. Content of chlorophyll a، b and total decreased in female plants sprayed with 1 and 10 mg/l ABA. Male plants showed a decrease in chlorophyll content only in high ABA levels (10 mg/l). ABA treatment did not affect carotenoid content in male plants but it caused the decrease of carotenoids content in female ones. Anthocyanin content decreased by treatment with 10 mg/l ABA in male plants but in females، anthocyanin content increased with ABA treatment (1 and 10 mg/l). In both of female and male plants، flavonoids A 270 on leaf increased in 1mg/l ABA but flavonoids A 330 on leaf did not change. Flavonoids A 300 increased in 1mg/l ABA in male plants and in 10 mg/l ABA in female ones. The content of Δ9_tetrahydrocannabinol (THC) increased the treated plants with ABA. This study showed that male and female plants of cannabis respond to ABA differently. ABA can increase secondary metabolites such as anthocyanin and flavonoids and decrease primary metabolites such as chlorophyll and carotenoids.