乾旱處理對長實金柑花芽形成及開花之影響

Effects of Drought in Flower Bud formation and Flowering of Fortunella margarita.

黃弘斌(Hung-Ping Huang)

指導教授 ： 林書妍

國立臺灣大學/生物資源暨農學院/園藝暨景觀學系/碩士(2019年)

https://doi.org/10.6342/NTU201903076

摘要

本試驗藉由土壤水分含量40-45%及30-35%兩種乾旱程度處理長實金柑，於處理期間採樣進行石蠟切片，並記錄葉片水分張力及葉片水分潛勢，了解乾旱處理期間花芽分化情形及葉片乾旱指標的變化，觀察乾旱結束後抽梢及開花情形，探討乾旱對長實金柑生長開花之影響。2018年2月2日至2月23日於日夜溫25/20℃走入式人工生長箱進行第1次乾旱試驗，試驗期間植株發生大量落葉。2018年4月23日至5月14日於室外塑膠遮雨棚下進行21日的第2次乾旱試驗，乾旱期間乾旱處理葉片水分潛勢最低達-3.06 MPa及- 3.48 MPa，水分含量最低達49.7%及43.4%，兩者復水後水分含量皆回升至與對照組相近。2019年3月29日至4月16日於玻璃水牆溫室內進行18日的第3次乾旱試驗，乾旱期間乾旱處理葉片水分潛勢最低達-1.71 MPa及-2.24 MPa，水分含量最低達48.8%及45.1%。兩次乾旱處理組的葉片水分潛勢與含水量，於處理期間皆顯著低於對照組，顯示 乾旱處理確實對長實金柑造成逆境。第1次乾旱試驗，乾旱處理組於復水後第6週每盆累積平均抽梢數為6.2與7.8，與對照組無差異。第2次乾旱試驗，乾旱處理組於復水後第6週每盆累積平均抽梢數為8.6及8.0，顯著高於對照組。第3次乾旱試驗，乾旱處理組於復水後第6週，每盆累積平均抽梢數為6.9與5.3，與對照組無差異，顯示乾旱處理影響長實金柑盆栽抽梢數的效果不穩定。第2次試驗，乾旱處理組於復水第2週累積開花數分別為6.54及6.41顯著高於對照組；乾旱處理組於復水第2週一次梢開花比例皆為87.5%，顯著高於對照組，但於復水第3週分別降至33.3%及25.0%，顯示乾旱具有集中一次梢花期與增加花數之效果。第3次試驗，乾旱處理組累積開花數及一次梢開花比例與對照組無差異，推測其開花情形與第2次乾旱不同，由環境溫度差異導致。長實金柑芽體經土壤水分含量40-45%及30-35%處理後，約在乾旱第2週可分化至花萼原體形成，達到花芽分化之不歸點。長實金柑的芽體經乾旱處理，花芽分化各階段所需時間減少，顯示乾旱具有加快芽體花芽分化之效果。第2次乾旱的乾旱處理組芽體平均分化階段高於第3次乾旱的處理組芽體平均分化階段，且第3次芽體有較高比例處於花芽分化階段，並維持較長的時間。綜合上述結果，乾旱雖具有加速芽體分化之可能，但溫度對長實金柑開花影響力仍相當重要。

關鍵字

花芽分化 ； 石蠟切片 ； 土壤水分含量

並列摘要

In this research, we discussed change of soil water content 40-45% and 30-35% drought treatments on fortunella margarita. During the drought, we collected bud for paraffin section, recorded leaf water potential and leaf water content. After rehydration, shoot flush and flowering were recorded. During the first drought treatment in day/night temperature 25/20℃ chamber, from February 2nd to February 23rd,2018, the plants were severe defoliated. During the second drought treatment at outdoor plastic canopy, from April 23rd to May 14th 2018, the low leaf water potential of drought treatment was -3.06 MPa and -3.48 MPa, and the lowest leaf water content of drought treatments were 49.7% and 43.4%. During the third drought treatment at water wall green house, from March 29th to April 16th,2019 the low leaf water potential of drought treatment were -1.71 MPa and –2.24 MPa and the low leaf water content of drought treatment were 48.8% and 45.1%. Leaf water potential and water content of both drought treatment were lower than control. Indicated the drought treatments did cause water stress to Fortunella margarita. On the first drought treatment, the average flush number of potted plants in drought treatment were 6.20 and 7.80, which were similar to control. On the second drought treatment, the average flush number of potted plants in drought treatment were 8.6 and 8.0, which were higher than control. On the third drought treatment, the average flush number of potted plants in drought treatment were 6.9 and 5.3, which were similar to control. The shoot of plant in drought treatments flushed in 2 weeks of all drought treatments. The change of drought treatment in flush number of potted F. margarita was unstable. In the first drought treatment, F. margarita did not blossom because of the high moisture and low light. In the second drought treatment, the flower number of drought treatment were 6.54 and 6.41, which were higher than control at the second week after rehydration. The ratio of flowering 1st flush of drought treatment was 87.5%, which were higher than control at the second week after rehydration. The ratio of flowering 1st flush of drought treatment was 33.3% and 25.0%, which were similar to control at the third week after rehydration. Drought treatments increased flower number of 1st flush and concentrated flowering period of 1st flush. In the third drought treatment, the flower number of drought treatments were similar to control. The ratio of flowering 1st flush was similar to control. The difference of flowering performance between the second drought treatment and the third drought treatment were caused by environment temperature. The sepal premordia of bud was observed at the second week after drought treatment. The period of flower bud differiation stages were shorten after drought treatment. The average bud stage of the second drought treatment was high than the third drought treatment. The ratio of bud in flower bud differentiation of the third drought treatment was lower than the second treatment, and higher ratio of bud in the third drought treatment were differetiantion stage for long period. The result demonstrates that the period of flower bud differentiation of F. margarita are shorten by drought treatment, but the effect of temperature is still important for flowering of F. margarita

並列關鍵字

flower bud differentiation ； paraffin section ； soil water content

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