Effects of ABA on primary terpenoids and Δ9-tetrahydrocannabinol in Cannabis sativa L. at flowering stage

This work examined the effects of exogenously applied abscisic acid (ABA) on the content of chlorophyll, carotenoids, alpha-tocopherol, squalene, phytosterols, Delta(9)-tetrahydrocannabinol (THC) concentration, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) and 1-deoxy-D-xylulose 5-phosphate synthase (DXS) activity in Cannabis sativa L. at flowering stage. Treatment with 1 and 10 mg l(-1) ABA significantly decreased the contents of chlorophyll, carotenoids, squalene, stigmasterol, sitosterol, and HMGR activity in female cannabis plants. ABA caused an increase in alpha-tocopherol content and DXS activity in leaves and THC concentration in leaves and flowers of female plants. Chlorophyll content decreased with 10 mg l(-1) ABA in male plants. Treatment with 1 and 10 mg l(-1) ABA showed a decrease in HMGR activity, squalene, stigmasterol, and sitosterol contents in leaves but an increase in THC content of leaves and flowers in male plants. The results suggest that ABA can induce biosynthesis of 2-methyl-D-erythritol-4-phosphate (MEP) pathway secondary metabolites accumulation (alpha-tocopherol and THC) and down regulated biosynthesis of terpenoid primary metabolites from MEP and mevalonate (MVA) pathways (chlorophyll, carotenoids, and phytosterols) in Cannabis sativa.