The experiments were conducted, to study the effect of 3 concentrations of each of indole butyric acid (25,50 or 100 ppm )and Mepiquat chloride (125,250 or 500 ppm ) on the active ingredients content of Petroselinum hortense L.
The experiments were designed in RCBD, and each treatment was replicated 3 times. L.S.D. test at level of 0.05 was used to compare the differences between means.
Result showed that the percentage of active ingredients of the plant extracts (essential oil , coumarin, flavonoids),were significantly increased with the increase of indole butyric acid compare with control treatment. However, application of Mepiquat chloride decreased them compare with control treatment.
Indole butyric acid increased endogenous gibberellic acid(GA) and indole acetic acid(IAA) while Mepiquat decreased them. This study proved that growth regulators of the plant as a natural tool to increase active ingredients for their medical value.