Seed Germination and Storage of Pasania glabra (Thunb. ex Murray) Oerst

子彈石櫟種子的發芽與貯藏

楊正釧(Jeng-Chuann Yang) ； 郭幸榮(Shing-Rong Kuo)

《台灣林業科學》 33卷4期 (2018/12) Pp. 277-290

https://doi.org/10.7075/TJFS.201812_33(4).0003

摘要

Pasania glabra is a native tree species of Taiwan and is estimated to be a near-threatened plant. The purpose of this study was to examine the germination characteristics and seed storage behavior of P. glabra so as to determine efficient pretreatment for germination and an appropriate seed storage method. Results showed that seeds of P. glabra were dormant, and the dormancy could be broken by low-temperature stratification. Fresh mature seeds of P. glabra germinated slowly and took about 20 wk to completely germinate with a mean germination time (MGT) of about 70 d under fluctuating temperatures of 30/20℃ with 8 h of light. However, stratification at 1 and 4℃ was unable to efficiently improve germination percentages but significantly decreased the MGTs in a germination period of 20 wk, and 1 and 4℃ stratification for 2~12 mo completely broke the dormancy of P. glabra seeds. The MGT of fresh mature seeds significantly decreased from about 70 d to about 30 d after 4 mo of stratification at 4℃. Therefore, pretreatment with 4℃ chilling for the germination of P. glabra seeds is practical for nursery operations. We suggest that prechilling at 4℃ for 4 mo should be applied to fresh mature seeds of P. glabra. Furthermore, fresh mature seeds of P. glabra were extremely sensitive to desiccation. Seeds completely lost viability when the moisture content (MC) dropped below 25%. However, P. glabra seeds maintained their initial viability for up to 2 yr when stored at 1~4℃ with moist sphagnum. Thus, seeds of P. glabra are defined as having temperate-recalcitrant storage behavior due to their extreme intolerance of dehydration and high viability with low-temperature moist storage. The optimal seed storage conditions of P. glabra are moist storage at 1~4℃ for fresh mature seeds, and the initially germinable seeds still had germinability for up to 2 yr.

關鍵字

Pasania glabra (Thunb. ex Murray) Oerst ； germination ； temperate-recalcitrant ； seed storage ； stratification

並列摘要

子彈石櫟(Pasania glabra (Thunb. ex Murray) Oerst.)是臺灣列為接近威脅等級的原生樹種，本研究目的在瞭解子彈石櫟種子發芽特性及種子儲藏性質，並確定其有效的發芽前處理及適當的貯存方法。結果顯示子彈石櫟種子具休眠性，低溫層積可以解除其休眠。鮮採的子彈石櫟成熟種子在30/20℃變溫條件下發芽緩慢，約需20週才能全部完成發芽，平均發芽日數約70日。在20週的發芽期計算基礎下，1與4℃層積無法有效提升子彈石櫟種子的發芽率，但能顯著降低其平均發芽日數，且在1與4℃層積經2～12個月後能完全解除種子休眠。經4℃層積4個月後，子彈石櫟種子的平均發芽日數從新鮮種子的約70日顯著下降至約30日，因此，4℃層積發芽前處理對本種的育苗作業甚具實用價值，我們建議應該採用經4個月的4℃層積來解除其種子休眠。子彈石櫟種子對乾燥非常敏感，當種子含水率被降到25%以下時就死亡殆盡，但當其以水草濕藏在1~4℃時，於2年內仍能保有原來活力，以其非常不耐旱及能在低溫濕藏時維持活力之特性，故將其歸類為溫帶異儲型。儲藏子彈石櫟種子的最好方法是將新鮮種子以1~4℃濕藏之，於2年內仍能保持原有活力。

並列關鍵字

子彈石櫟 ； 發芽 ； 溫帶異儲型 ； 種子貯藏 ； 層積