Effect of drought stress, asscorbate and gibberellin foliar application on some morphological traits, RWC and cell membrane stability of Thyme (Thymus vulgaris L.)

Due to study the effect of drought stress, ascorbate and gibberellin foliar application on some morphological traits, relative water content and cell membrane stability, an experiment was done as factorial in the basis of completely randomized design in 4 replication during 2012 in Islamic Azad university shahr-e-Rey branch and pakdasht Region. Irrigation in 3 levels (1/3 FC, 2/3 FC and FC), ascorbate in 2 levels (0 and 10 mM) and gibberellin in 2 levels (0 and 10 mM). The results indicated that instead of ascorbate and gibberellin double interaction and drought stress and gibberellin on effects Root length, drought stress and Ascorbate on relative water content and cell membrane stability, triple interaction effects on branch number per plant and cell membrane stability, the others were significant. The triple interaction effect results indicated that, 10 mM ascorbate and gibberelline foliar application in FC irrigation condition gained to maximum amounts of root dry weight (0.72g), shoot dry weight(0.45), branch numper per plant(20), leaf area (50.21 cm2) and leaf dry weight (0.20 g) as the main elements of thyme essential oil production. Ascorbate and gibberellin application in both stress and non stress conditions increased RWC and reduced cell membrane leaching as the main indicator of cell membrane stability.