The effect of different treatments on breaking dormancy and stimulate germination of Firmiana simplex

Given that the seed germination of Chinese parasol tree (Firmiana simplex L.) and hence its propagation is experiencing difficulties, therefore, this study investigates the factors limiting seed germination of mentioned tree and how to troubleshoot them are discussed. This experiment was conducted in 2014 in a completely randomized design with a factorial arrangement with three replications in the laboratory of Horticultural Science Department, Gorgan University of Agricultural Sciences and Natural Resources of Iran. In order to remove physical dormancy (impermeable seed coat) mechanical scarification treatments with fine sand (shaking seeds and building sand for 5, 10 and 15 minutes), hot water (70 °C) and acid (treatments of seeds with solution of concentrated sulfuric acid for 1, 5 and 10 minutes and then rinse by tap water for 20 minutes) were used. Moreover to remove the physiological dormancy, stratification of seeds were applied for 30, 45 and 60 days in 3-6oC. The results showed that the highest percentage of seed germination was related to scarification by sand (78%) for 15 minutes and stratification for 30 days. The lowest seed germination rate among all treatments was related to control (4.6%). In overall, it can be concluded from various treatments which used to break dormancy in seeds of Firmiana simplex, it is clear that the seeds of mentioned tree include dual seed dormancy, including seed coat and embryo dormancy. The results also showed seedling establishment of 86.6 % related to combination of scarification and stratification in the mentioned treatment has been much higher than other treatments, specially control (without scarification).