GA_3處理的台灣肖楠樹木芽體與木質部流出液之荷爾蒙含量變化

Changes in Contents of Plant Hormones in Bud Tips and Xylem Sap of GA_3-Treated Calocedrus formosana Trees

鍾振德(Jeng-Der Chung) ； 郭幸榮(Shing-Rong Kuo) ； 簡慶德(Ching-Te Chien)

《台灣林業科學》 33卷4期 (2018/12) Pp. 305-317

https://doi.org/10.7075/TJFS.201812_33(4).0005

摘要

本研究台灣肖楠樹木經由不同的時間處理激勃素A_3 (GA_3)後，分析芽體與木質部流出液之激勃素、離層酸(ABA)與吲乙酸(IAA)含量變化。以大雪山種子園開花旺盛(no. 11)與稀疏(no. 22)兩類型營養系，於3、4與5月分別於枝條上處理GA_3，以7~10天間隔收集芽體，分析荷爾蒙之變化，而對照組為相同的台灣肖楠營養系，可天然開花之六龜種子園。處理GA_3前，分析no. 11與no. 22芽體之GA_1與GA_3含量，與對照組沒有差異，含量1.3~18.6 ng (g.dry weight (DW))^(-1)；處理GA_3後，兩營養系芽體之GA_1與GA_3含量皆於花芽分化之際達到最大，但花芽分化後下降至高峰的1/2~1/10，其含量仍有10~800 ng (g.DW)^(-1)，而ABA含量在花芽分化之際，卻與激勃素相反，含量快速下降至高峰的1/5~1/50，IAA則在花芽分化時才出現，含量32~143 ng (g.DW)^(-1)，其它時間IAA含量趨近0，推測花芽分化伸展時可能需要IAA參與。然而，同時期對照組六龜種子園兩營養系的GA_1與GA_3含量都在10 (g.DW)^(-1)以下。結論是激勃素可以誘導台灣肖楠開花，但台灣肖楠在自然條件下開花與激勃素無關。GA_3處理台灣肖楠樹木枝條後第1星期，木質部流出液含有大量的GA_1,GA_4,GA_9，但GA_3的含量卻為0 ng (g.DW)^(-1)；GA_3處理後第3星期，木質部流出液無GA_9，而GA_4含量與對照組沒有顯著差異，推測GA_9可能扮演中繼運送的角色，在到達芽體前轉變成具有生物活性之激勃素GA_1與GA_4。

關鍵字

台灣肖楠 ； 花芽分化 ； 激勃素 ； 離層酸 ； 吲乙酸 ； 木質部流出液

並列摘要

This paper analyzed time-course changes in concentrations of gibberellins, abscisic acid (ABA), and indoleacetic acid (IAA) from bud tips and xylem sap of Calocedrus formosana trees that had been treated with gibberellin A_3 (GA_3). GA_3 was applied to the branches of good flowering clone no. 11 and poor flowering clone no. 22 of C. formosana trees at the Tashueshan seed orchard in March, April, and May, and then bud tips were collected every 7~10 d. In addition, the same clones (nos. 11 and 22) at the Liukuei seed orchard that flower naturally were selected as controls. The GA_1 and GA_3 contents of bud tips from the 2 clones at the Tashueshan and Liukuei seed orchards were quantified and showed no significant differences; the GA_1 and GA_3 contents were about 1.3~18.6 ng (g.dry weight)^(-1). After treatment with GA_3 at the Tashueshan seed orchard, GA_1 and GA_3 contents in bud tips rapidly increased until the floral buds had differentiated, and then the contents were reduced 1/2~1/10-fold to 10~800 ng (g.DW)^(-1). Nevertheless, GA_1 and GA_3 contents in bud tips from the Liukuei seed orchard (control without GA_3 treatment) were all ＜ 10 ng (g.DW)^(-1). In conclusion, gibberellins could induce flowering of C. formosana, but there was no relationship between gibberellins and floral bud initiation. The ABA content in bud tips rapidly decreased during the bud collection period and had dropped 1/5~1/50-fold during floral bud initiation. The IAA content in bud tips suddenly appeared during floral bud initiation, and the concentration was 32~143 ng (g.DW)^(-1), but the IAA content was almost zero after floral bud initiation. We speculated that IAA was possibly involved in floral-bud initiation. Furthermore, the xylem sap in shoots was collected for analysis of GAs after treatment with GA_3. At 1 wk after treatment, large amounts of GA_1, GA_4, and GA_9 were found in the xylem sap, but there was no GA_3. Three weeks later, contents of GA_1 and GA_4 were still detected in the GA3 treatment and control groups, but GA_9 was not found. Therefore, GA_9 may play a transport role from branches to buds, and then GA_9 is converted to GA_1 and GA_4.

並列關鍵字

Calocedrus formosana ； flower initiation ； gibberellin ； abscisic acid (ABA) ； indoleacetic acid (IAA) ； xylem sap.