Foliar Application Effect of Gibberelic Acid on Growth, Volatile Oil and Nutrients Content of Satureja hortensis L.

A filed experiment based on randomized complete blocks design with three replications was carried out at Department of Medicinal Plants, Higher Education Complex of Shirvan, Northeast of Iran, to investigate the foliar application effect of gibberellic acid on growth traits and essential oil of Satureja hortensis L. during spring and summer of 2015. Four different gibberllic acid (GA(3)) concentrations including 0 (spray with distilled water as control), 100, 200 and 300 ppm were used. The results showed that GA(3) treatments significantly affected growth traits of Satureja hortensis. Plant height, number of nods and number of branches per plant were increased by increasing GA(3) concentration. However, internod distance was not significantly affected by treatments. The height of plants treated with 0 and 300 ppm of GA(3) were 35.8 and 46.7 cm, respectively. Plant dry weight, the leaf chlorophyll content, essential oil (%) and essential oil yield per unit area were also affected by GA(3) concentrations. Dry weight of plant treated with 0 and 300 ppm GA(3) were 253.3 and 470 g m(-2), respectively. Essential oil (%) of plants was increased by increasing GA(3) concentration. Plants treated with 0 ppm had the lowest (3.3%), while plants treated with 300 ppm of GA(3) had the highest (4.5%) essential oil. However, there was no observed significant difference between essential oil (%) of plants treated with 100 and 200 ppm of GA(3). The essential oil yield of plants treated with 0 and 300 ppm were 84.9 and 211.5 kg ha(-1), respectively. Leaf nutrients concentrations (N, P and K) were also significantly enhanced by foliar application of GA(3). The application of 300 ppm GA(3), increased the content of leaf-N by, leaf-P by and leaf-K by. It can be concluded that exogenous application of GA(3) improved growth traits and quality of Satureja hortensis L. plants.