Studies on the Dormancy Breaking of Rhynchelytrum repens Seeds
Chin-Jin Hou Chung-Chaun Wu
Department of Agronomy,
The purpose of this research was to study the effects of dormancy breaking on the germination of Rhynchelytrum repens seeds. The freshly harverted seed of Rhynchelytrum repens seeds showed a strong dormancy. Different dormancy breaking treatments, including stratification, freezing, leaching, gibberellic acid (GA3) and scarification, were thus conducted. The results were summarized as follows:
The treatment of stratification at 5℃for 8 weeks showed highest germination (78%) and germination rate index(GRI). Highter temperature and /or shooter duration of the treatment showed less effect.
The freezing treatments were effective in breaking the seed dormancy of Rhynchelytrum repens. The germination percentage of those seeds under freezing treatments were significantly increased than those without treatments. The seeds under 3-day freezing treatments showed highest germination rate in the 20/150C growth chamber. So was the GRI under the same condition.
The leaching treatments also significantly increased the germination percentage and the GRI of the Rhynchelytrum repens seeds. The germination percentage and the GRI for those seeds under 2-day leaching were higher than those under the treatment of 1-day leaching.
The sulfuric acid and gibberellic acid (GA3) treatments showed partially effectiveness in increasing the germination percentage and the GRI of the Rhynchelytrum repens seeds.The optimum concentration was 100% for sulfuric acid and 0.5% for GA3 which raised percentage germination of this grass seeds to 41% and 34%, respectively.
Key words：Rhynchelytrum repens , seed germination, dormancy breaking, stratification treatments, freezing treatments, leaching treatments, gibberellic acid (GA3), sulfuric acid treatments, chemical medicament.