| Acer truncatum is a promising energy plant produced biodiesel because of a higher oil content of seeds. In adition, A. truncatum can be utilized as wood, food, medicine and industrial resource. However, the germination percentage of seeds collected freshly is very low, which usually is difficult for domestication and planting of this species. In the present paper, we use the mature A. truncatum seeds to investigate seed dormancy type and methods to break dormancy. The results were as follows:The water content of A. truncatum seeds collected newly was 0.43 g H2O (g DW)-1 (g g-1), seeds could survive to a water content of 0.100 g g-1. The 1000 weight of seeds collected freshly was 150±25 g. These results, taken together, indicated that A. truncatum seed was an orthodox.At the optimum temperature (15℃), germination of A. truncatum seeds collected freshly was only about 4%, but that of excised embryos was 100% within 7 days. Therefore, A. truncatum seed was of dormant and the dormancy might be imposed by its seed coat.A. truncatum seed was water-permeable. The water uptake by whole seeds rapidly increased during initial phase of imbibition, followed by a slow uptake (phase II). The phaseⅡof whole seeds was much longer than that of excised embryos and half-seeds. The optimum temperature was 10 and 15℃for germination of whole seeds, and 15℃for germination of half-seeds. The germination percentage of excised embryos was above 85% at 10-30℃, but no normal seedling survived at 25 and 30℃.After-ripening for 120 d or cold stratification for 7 d could effectively release dormancy of A. truncatum seeds.Treatments of scarification, kinetin and ethylene promoted seed germination. The germination of seeds was not influenced by light or gibberellic acid treatment.It was concluded that the dormancy type of A. truncatum seeds was type 3 non-deep physiological dormancy, i.e. during dormancy release, the response of seed germination on temperature was from medium to both high and low. |
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