The effects of auxin and gibberellin were investigated on Euphorbia trigona plants grown in a complete randomized block design under greenhouse conditions. One-minute pretreatments including auxin regulators NAA, IBA, and IAA, (0, or 500 mg/l), followed by treatments containing IAA, IBA and NAA (250 mg/l), and also GA treatment (250 mg/l ( without any pretreatments were applied on two-month old cuttings. After 4 months, fresh and dry weights of shoots and roots, and shoot total terpenoid contents were measured. In some samples, shoot extract was analyzed using GC-MS. Fresh and dry weights of shoots did not show any response to the treatments and pretreatments. NAA treatment had the most positive affected root fresh and dry weights. The highest significant increase in terpenoid content was observed in NAA treatment and NAA and IBA pretreatments. GC-MS analysis showed that the chemical compounds in the extract mainly included sesquiterpenes, diterpenes, fatty acids, esters, and steroids. Bis-2-ethylhexyl phthalate contents under NAA treattment and control were 49.31% and 9.59%, respectively; Hexadecanoic acid contents in NAA and control were 2.73% and 2.12%, respectively; 6,10,14-trimethyl-2-pentadecanone content in NAA treatment and control were 3.16% and 1.42%, respectively, and Neophytadiene content under control and gibberellin treatment were 0.94% and 1.64%, respectively. Applying hormones is suggested to result in a positive effect on terpenoids and fatty acids anabolic pathways in Euphorbia trigona.
