| Summary: | 碩士 === 國立臺灣大學 === 園藝學研究所 === 89 === The dormancy and optimal conditions for germination of native Acer species in Taiwan were studied to accelerate seed propagation due to their high ornamental value. Samaras (fruits) of Acer kawakamii Koidzumi, A. serrulatum Hayata, A. morrisonense Hayata, A. albopurpurascens, and A. buergerianum Miq. var. formosanum（Hayata）Sasaki were collected at Luodung of Ilan county, Yang Ming mountain of Taipei, and the Highland Experimental Farm of National Taiwan University at Nantou county. The harvested fruits were stratified in moist peat moss wrapped in perforated polyethylene film at 5℃ in darkness. All samples were then germinated in Petri-dishes (9cm), on two layers of filter papers moistened with distilled water. Stratification increased germination percentage and germination rate for A. morrisonense, A. serrulatum, and A. kawakamii, and the optimum stratification period of the former two species was 1.5 months, and the latter one was more than 2 months. Germination was increase by removal of the pericarp or testa. The optimal temperature of germination was 25oC for seeds but below 20oC for samaras. Treated with 500ppm gibberellin promote germination on pericarp-removed seeds of A. morrisonense, and A. kawakamii, but have no effect on that of A. serrulatum, and A. buergerianum var. formosanum or on intact fruits of the four species. Germination percentage of A. serrulatum fruits increased; however the germination rate index reduced with delaying harvest date. These results suggest that seed dormancy of the native Acer species in Taiwan were coat-imposed and that pericarp and testa were both responsible for this effect.
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