Effect of different treatments on seeds dormancy breaking and germination of Fraxinus rotundifolia and Ailanthus altissima

This study was conducted in Tahlijan plantation near Shahrekord in autumn and winter climatic conditions in a given year. Seeds of two species, Ash (Fraxinus rotundifolia (and tree of heaven (Ailanthus altissima) were collected from selected trees and examined by Tetrazolium chloride and dormancy breaking tests (cold stratification for 3, 5 and 6 weeks). In order to investigate effect of different treatments on dormancy breaking and germination in the first step, each treatment as well as control were cultured in vitro in 4 replicates of 50 seeds, then the germination percentage and speed was measured. In the next step the effect of wintering on seeds germination was examined under 5 treatments; 1) scattering the seed on the soil surface 2) shallow burial, 3) plastic cover, 4) wire mesh-cage and 5) crystal jars by 16 replications inside and outside of water gutter in forest plantation. Following winter period these treatments were collected and the seeds viability was evaluated and compared with the first stage results. Germination percentage under 6 week’s stratification for ash and tree of heaven were 59.93 and 15.14, respectively. Seed germination percentage and speed- inside and outside of the water gutter- did not show any significant differences. The highest germination percentage was observed in shallow burial for Ash (53.35%) followed by crystal jars for tree of heaven (34.05%). Shallow burial treatment caused break seed dormancy break of Ash and an increase in speed of germination (p< 0.05). Seed dormancy break did not occur in soil surface treatment in which seeds were treated naturally.