The influence of chemical stimulators on decrease of Thymus kotschyanus allelopathic effect on Agropyron elongatum seed germination characteristics

This research was conducted to study the negative allelopathic effects of Thymus kotschyanus on seed germination of Agropyron elongatum. Also to find what chemical materials are able to decrease the mentioned effects. The chemical treatments were three levels of giberlic acid (GA3) (250، 500، 1000 ppm)، KNO3 (0. 1، 0. 2 and 0. 3%) and salicylic acid (100، 200 and 300 mg/lit). Allelopathic treatments were 5 levels of 0، 5، 25، 50 and 75 % concentrations of Thymus kotschyanus aerial parts extractions. Results showed that solution extracted from Thymus kotschyanus had a negative effect on seed germination of Agropyron elongatum while in contrast chemical stimulators improved germination. GA3 had the highest positive effect. Interaction of stimulators and allelochemicals had a significant (P <0. 01) effect on properties of germination speed، root length، shoot length، plant length and seed vigor index while no significant difference was observed for seed germination of Agropyron elongatum.