玉金香梨高接用花穗的花序芽發育

Development of Inflorescence Buds for the Top-grafting Flower-budwoods of Julip Pear

曹靖玟(Ching-Wen Tsao)

指導教授 ： 黃玲瓏

共同指導教授 ： 施昭彰

國立臺灣大學/生命科學院/生態學與演化生物學研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.01039

摘要

梨 (Pyrus spp.) 為溫帶果樹，是世界上重要的經濟作物之一。1976年農民張榕生成功研發高接梨技術，在台生產低緯度、低海拔的早熟梨果。目前國內的高接梨穗概屬日本育成品種，來源為日本進口以及高海拔地區的自產梨穗。本研究以台灣自行育出之低需冷性且生殖芽不耐高溫的台農三號——玉金香梨 (Julip) 為實驗材料，探討位於中、低海拔兩處果園中，梨樹上與地面交角為斜上與直立兩種梨穗的花序芽發育與碳水化合物含量變化。
本研究於民國九十八年七月到十月期間，每月自桃園拉拉山 (海拔約1000 m) 與農業試驗所 (TARI) (海拔約50 m) 採集玉金香梨穗。使用解剖顯微鏡和掃描式電子顯微鏡檢測花序芽形態發育過程，利用石蠟切片技術檢測其解剖構造，並以anthrone method檢測游離醣與澱粉含量。形態發育觀察結果發現：玉金香梨的花序芽由大約12枚鱗片與10枚苞片包裹1個花序所構成，而此花序上約有8個花始原與2個營養始原。根據花部器官的形成順序，將花序芽分化與發育之過程分為七個階段，分別為剛由營養芽轉化來的花序始原之花序始原期、各器官尚未分化的花始原之花始原期、五枚花萼始原突起的花始原之花萼期、五枚花瓣始原突起的花始原之花瓣期、第一輪雄蕊始原突起至第二輪雄蕊始原突起的花始原之雄蕊期、形成雌蕊始原環至五枚離生心皮生成的花始原之雌蕊1期，以及心皮內側形成凹陷的花始原之雌蕊2期。而花序芽發育情形：在拉拉山，七月為發育初期，八月時18 - 37.78%已有雌蕊產生，九月則大部分的花始原 (71.72-93.62%) 都有雌蕊產生，十月幾乎所有的花始原 (89.31-96.97%) 都至雌蕊2期。於農試所，七月已有雌蕊發育，八月時斜上梨穗有4.3%的死芽產生，九月時兩種梨穗皆有死芽產生，約21.75 - 57.75%。不論在拉拉山或農試所地區，斜上梨穗之花部發育皆早於直立梨穗。
醣類含量部分：梨芽的游離醣隨著時間有顯著變化，七月份含量最高，在拉拉山約35.73-42.16 mg/g DW，在農試所約21 mg/g DW；芽下枝條的澱粉隨著時間而漸累積，且其含量在拉拉山的斜上梨穗皆顯著高於直立梨穗，拉拉山斜上梨穗於十月份約131.69 mg/g DW，直立梨穗約93.64 mg/g DW，農試所於九月份兩角度梨穗皆約75 mg/g DW；芽下枝條的游離醣與澱粉含量在枝條的不同部位有顯著差異，上部為最高。花序芽發育與醣類含量之關係：隨著花序芽的發育，梨芽的游離醣與澱粉含量有下降的趨勢，而芽下枝條的澱粉則隨著發育呈現上升趨勢，因此梨的醣類含量的確與花芽分化發育有密不可分之關係。
拉拉山較平地涼爽，玉金香梨芽在七月開始分化，兩角度開始分化的時間雖然不同，但到十月份皆有良好的發育，且枝條於此時也累積了大量澱粉，嫁接後的萌芽率與開花率也頗高且一致，因此認為拉拉山的環境與氣候條件，較適合生產高接梨穗，且斜上梨穗可能比直立梨穗更適合用於嫁接，但考量自然界實際生長數量為直立梨穗較多之緣故，且直立梨穗的芽下枝條澱粉含量也有頗高的水準，所以經適當選擇，應仍可做為嫁接之用途。

關鍵字

玉金香梨 ； 嫁接梨穗 ； 花序芽發育 ； 游離醣含量 ； 澱粉含量

並列摘要

Pear (Pyrus spp.) is a temperate fruit tree with high economic value. Mr. Chang invented the technique of top-grafted pear in Taiwan in 1976. Now most top-grafting flower-budwoods are imported from Japan and some from high altitude area in Taiwan. In this study, horizontal and upright flower-budwoods of Julip pear were examined to verify the development of inflorescence buds and the sugar contents.
Flower-budwoods of Julip pear were sampled at Lalashan and Taiwan Agricultural Research Institute (TARI) from Jul. to Oct. Stereomicroscope, scanning electron microscope (SEM), and paraffin section were used to examine the external and internal structures of pear inflorescence buds. For the sugar contents, soluble sugar and starch were examined by anthrone method. An inflorescence bud of Julip is composed of twelve scales, ten bracts, and one inflorescence containing eight flower primodia and two vegetative primodia. Development of inflorescence buds on flower-budwoods of Julip pear was divided into seven stages.“Inflorescence primodium” stage was vegetative bud turning into inflorescence bud.“Flower primodium”stage was flower primodium without any flower organ initiated.“Sepal” stage was flower primodium with five sepals initiated.“Petal”stage was flower primodium with five petals initiated.“Stamen” stage was flower primodium with stamens of first and/or second rows initiated.“Pistil 1”stage was flower primodium with carpels initiated.“Pistil 2”stage was flower primodium with inside face-concaved carpels initiated. Inflorescence bud development was earlier at TARI than at Lalashan. At Lalashan, inflorescence buds were at early stages in Jul., and nearly at final stages in Oct. 18–37.78% flower primodia were with carpels in Aug. and 71.72–93.62% in Sep. At TARI, flower primodia with carpels already existed in Jul. Dead flower primodia were some in Aug. and 21.75–57.75% in Sep. Development of inflorescence buds was earlier on horizontal flower-budwoods than upright flower-budwoods at both areas.
Soluble sugar in buds had significantly difference among months with the highest contents in Jul. (Lalashan, 35.73–42.16 mg/g DW; TARI, about 21 mg/g DW). Starch in bud bases gradually accumulated among months (In Oct., Lalashan, 93.64–131.69 mg/g DW; In Sep., TARI, about 75 mg/g DW), and all were significantly higher on horizontal flower-budwoods than upright flower-budwoods at Lalashan. Soluble sugar and starch contents had significantly differences among different sites of shoots with their highest contents at upper site. During the development of inflorescence buds, soluble sugar and starch in buds decreased, and starch in bud bases increased. Therefore, the above results suggested that sugar is closely related to the inflorescence bud development of Julip pear.
The temperature is lower at Lalashan than at TARI. Development of inflorescence buds at Lalashan was from Jul. to Oct., and a large amount of starch was accumulated in bud bases in Oct. Moreover, sprouting and flowering of inflorescence buds were even, and their rate were high after top-grafting. Hence, we suggested that Lalashan is a suitable place to produce top-grafting flower-budwoods. Also, horizontal budwoods are better than upright budwoods for the more starch contents in the bud bases. However, upright budwoods were more in nature, and our results showed that starch in bud bases of upright budwoods indeed reached high contents. With appropriate selection, upright budwoods might be acceptable for top-grafting.

並列關鍵字

Julip pear ； top-grafting flower-budwoods ； development of inflorescence buds ； soluble sugar contents ； starch contents starch contents

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