紅檜與臺灣扁柏種子在不同水逆境模式下之發芽

Germination of Chamaecyparis formosensis and C. obtusa Var. formosana Seeds in Various Water Stress Regimes

林湘玲(Hsiang-Ling Lin) ； 郭幸榮(Shing-Rong Kuo)

《台灣林業科學》 18卷1期 (2003/03) Pp. 13-24

https://doi.org/10.7075/TJFS.200303.0013

摘要

本研究係以模擬野外可能出現的水逆境探討紅檜及臺灣扁柏種子在各種水逆境模式下的發芽表現，比較這二樹種的水逆境耐受力，結果顯示：(l)紅檜種子可忍受淹水而發芽，然臺灣扁柏種子在同樣條件的發芽力減退。(2)紅檜種子正常發芽所需之最低水勢為-0.3 MPa，臺灣扁柏為-0.1 MPa。由發芽含水率變化曲線觀之，越逾第1及第2門檻之含水率，紅檜約為27及33%，台灣扁柏則約為27及36%。(3)紅檜種子於-1.5 MPa水逆境下，活力能維持14d，在21d處理後逐漸下降，而臺灣扁柏在7d處理後即下降。(4)種子在吸水膨潤後遭受由-0.05 MPa逐日下降至-15 MPa的水逆境下，紅檜之發芽率並未顯著降低，而臺灣扁柏則不論發生於何時，發芽率即下降至達顯著差異。(5)種子於0至-0.5 MPa的水逆境為1循環，在不同循環次數下的發芽表現，紅檜種子之發芽率在各循環處理間差異不顯著，但發芽天數隨循環次數而上升。臺灣扁柏則各處理間差異顯著，發芽天數也隨循環次數而上升。綜觀上述模擬之水逆境，台灣扁柏種子所受之危害較紅檜種子為大，前者可發芽的水勢範圍較後者為小。

關鍵字

紅檜 ； 臺灣扁柏 ； 水勢 ； 聚乙二醇溶液 ； 發芽表現

並列摘要

This study investigated the germination performance and water-stress tolerance of Chamaecyparis formosensis Matsum and C. obtusa Sieb & Zucc var. formosana Hayata seeds by simulating water supply regimes which occur in the field. The following results were obtained. 1. Chamaecyparis formosensis seeds could germinate under water immersion, however, the germination percentage of C. obtusa var. formosana seeds was reduced in the same condition. 2. The minimum water potential requirements for seed germination of C. formosensis and C. obtuse Var. formosana were -0.3 MPa and -0.1 MPa, respectively. The moisture contents of seeds over the 1(superscript st) and 2(superscript nd) thresholds were 27 and 33%, respectively, for C. formosensis, and were 27 and 36%, respectively, for C. obtusa var. formosana seeds. 3. Seed viability of C. formosensis was substantially retained under a water pontential of-1.5 MPa for 14 d, but it had decreased by 21 d. However, that of C. obtusa var. formosana viability had decreased by 7 d at the same water potential 4. As the water potential was gradually decreased from -0.05 to -1.50 MPa day by day after 1 to 7 d of imbibition by seeds, germination of C. formosensis was reduced but the change was not significant. However, germination of C. obtusa var. formosana seeds was significantly reduced 5. As the water potential was reduced from 0 to -0.5 MPa which was considered 1 cycle, germination of C. formosensis among various numbers of cycles showed non-significant differences. In contrast, both germination percentages and germination days of C. obtusa var. formosana significantly decreased for various numbers of cycles. Thus, seeds of C. obtusa var. formosana are more sensitive to water stress than are seeds of C. formosensis.

並列關鍵字

Chamaecyparis formosensis ； Chamaecyparis obtusa var. formosana ； water potential ； PEG8000 ； germination performance