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克服鐘萼木種子的生理休眠
Overcoming Physiological Dormancy of Bretschneidera sinensis Hemsl. Seeds
摘要
鐘萼木（Bretschneidera sinensis Hemsl.）種子是否具有休眠現象有所爭議。本研究確認此罕見孑遺樹種的種子休眠性質，並評估種皮去除、低溫層積和激勃酸（GA_3）浸泡的組合處理對鐘萼木種子發芽的影響。研究結果顯示未經任何處理的對照組種子在12週培養期間完全沒有發芽，表明種子具有顯著的休眠。相對地，經過不同組合處理的種子發芽率從0.8到65.0%不等。其中以經4週4℃低溫層積、種皮去除再100 ppm GA_3浸泡24 h組合處理之種子發芽率最高且平均發芽時間最短。種皮去除和低溫層積顯著增加了種子發芽率，GA_3浸泡有增加種子發芽率之趨勢，但未達到顯著水平。GA_3浸泡顯著縮短種子平均發芽時間，種皮去除和低溫層積則對於種子平均發芽時間無顯著影響。本研究結果指出鐘萼木種子發芽表現主受種皮去除與層積溫度以及二者交感作用所影響。
並列摘要
Bretschneidera sinensis Hemsl. is a rare relict tree species in Taiwan; however, the seed dormancy of this species is still controversial. In this study, we evaluated the effects of decortication, cold stratification, gibberellic acid (GA_3) immersion, and their interactions on the germination of B. sinensis seeds. Results showed that control seeds with no treatment did not germinate during a 12-wk incubation period, indicating that seeds had significant dormancy. In contrast, seeds with other treatment combinations exhibited 0.8% to 65.0% germination percentages. Among them, the highest germination percentage and shortest mean germination time were observed in the treatment combination with 4 wk. of 4°C cold stratification, decortication, and then immersion in 100 ppm GA_3 for 24 h. Decortication and cold stratification significantly increased seed germination percentages. Although GA_3 immersion also increased seed germination percentage, the effect did not reach a significance level. GA_3 immersion did significantly shorten the mean germination time of seeds, while decortication and cold stratification did not. This study demonstrated that fresh B. sinensis seeds have physiological dormancy, which can be overcome through a combination of cold stratification, decortication, and GA_3 immersion.