Study on seed dormancy breakage treatments and some germination properties of Colchicum kotschyi Boiss. as a medicinal plant

In order to evaluate germination behavior of Colchicum seed, an experiment was conducted as factorial based on a randomized complete design with four replications. The experimental treatments were all combination of priming at three levels (warm stratification, cold stratification, control), gibberellic acid at two levels (0,500 ppm) and incubation temperatures at 8 levels (2, 5, 10, 15, 20, 25, 30, 35). After applying the priming treatments, gibberellic acid treatment was applied and then the response of seed germination at constant temperatures were assessed in the germinator. The effect of temperature on germination components was significant. Germination was occurred only in warm stratification. Generally, germination was started by a very slow trend and after seeds were set at incubation temperatures, at least 40 days were lasted to germination occurred. There was no germination at 2°C. By increasing temperature at a range of 5-15°C, germination percentage was increased and then was stopped at 25°C. Germination uniformity at 20°C was more than other temperatures. The meanest germination time was observed at 20°C and the least mean germination time was at 15°C. Gibberellic acid (single application) had no effect on seed germination. Based on two regression models, the cardinal temperatures (Tbase, Topt, Tmax) were (1.38-1.72°C), (12.7516.10°C) and (24.12-25.65°C), respectively.