Effect of Nacl and Gibberellic Acid on Seed Germination and Seedling Growth of Five Medicinal Plants

In order to examine the effect of sodium chloride (NaCl) and gibberillic acid (GA3) on seed germination and seedling growth of five medicinal plants, a study was conducted under controlled conditions. Medicinal plants seeds were exposed to different concentrations of NaCl (0.05, 0.5 and 1.5 mol/l) and GA3 (100, 200 and 300 ppm) aqueous solutions, solely or combined under in vitro culture conditions. the NaCl solutions at 0.5 and 1.5 mol/l concentrations showed negative effects on seed germination in the five tested species even when combined with GA3. However, all tested seeds germinated regularly when NaCl solution with the concentration of 0.05 mol/l was used alone or with various levels of GA3. The NaCl solution with 0.5 mol/l concentration impeded germination of dill, peppermint, coriander and thyme seeds; whereas it increases germination percentage and germination speed of dragonhead. GA3 solution significantly increased seed germination percentage, seed germination speed, and seedling length in all plants except thyme. Simultaneously use of GA3 and NaCl reduced the negative effects of NaCl on the most of measured factors.