金柑生育特性及花期調節之研究

Studies on Growth Characteristics and Flowering Regulation of Kumquat (Fortunella margarita (Lour.) Swingle)

張允瓊(Yung-Chiung Chang)

指導教授 ： 張育森

共同指導教授 ： 陳右人

國立臺灣大學/生物資源暨農學院/園藝學研究所/博士(2014年)

https://doi.org/10.6342/NTU.2014.03046

摘要

金柑為宜蘭地區重要之果樹種類，然因加工食用方式，果實品質不受重視，栽培粗放。現今自然健康果品需求日增，金柑以「鮮果」取代加工產品，除可保留果品營養價值，亦可為傳統產業創造轉型契機，增加產業收益。然而迥異於加工果品，鮮食果品價格受品質影響甚鉅，因此金柑傳統栽培方式亟需改進以符合需求。有鑑於金柑樹體特性及相關栽培技術等參考資料極為有限，因此本研究旨在建立完整之金柑生育資料，並探討影響樹體開花之關鍵條件，以發展實用之栽培調控技術，達到枝梢管理、分散產期與提昇果實品質等目的。
供試材料為2009年購自青果合作社，使用嫁接於枳殼（Poncirus trifoliate (L.) Raf.）之二年生長實金柑（Fortunalla margarita (Lour.) Swingle），試驗期間為2010-2011年。生理特性探討結果顯示，金柑於一年中可萌發3-4次新梢，2010年樹體之二、三、及四次梢分別於五月中旬、六月上旬及九月上旬萌發；約為於一次梢萌發後70-80、112-122及168-178天；但2011年之樹體，其新梢3月下旬大量萌發一次梢，並於7及8月中旬萌發二及三次梢，但數量遠低於2010年。枝條開花率及開花數隨枝梢萌發順序增加而降低。2010年之一次梢具4次開花高峰，而2011年萌發之一次梢則具5次開花高峰。2011年試驗結果顯示，一次梢的五次花期中，開花期為六月中旬之第二次花所形成之果實，較可能發育並成熟，其餘花期所形成之小果，多於初期著果3-4週後落果。
本研究探討不同溫度對盆栽金柑枝梢生長及開花能力之影響。溫度處理組分別為T 25-32、T 17-25、T 22及T 18。 T 25-32 處理組為於日/夜溫25/18°C處理2週後，隨後移至32/25°C處理28週。T 17-25 處理組為於日/夜溫17/10°C處理4週後，隨後移至25/18°C處理26週。T 22及T 18處理組則於試驗期間，分別放置於日/夜溫22/18°C及18/13°C。另於簡易塑膠棚溫室中設置一對照組，以進行自然環境條件比對。結果顯示，金柑於高溫32/25°C下，新梢萌發數量增加且萌梢次數頻繁，但高溫縮短新梢營養生長期，致使枝梢提早停梢，枝梢長度明顯降低。金柑生長溫度低於22°C以下，新梢萌發即明顯受到抑制。然而低溫增長枝梢營養生長期，因此，低溫處理組之枝梢生長勢明顯較高溫處理組優勢。日/夜溫25/18°C以上，顯著促進金柑開花。高溫32/25°C下，金柑枝梢開花次數增加，且總開花數顯著高於其他處理組。相對地，日/夜溫22/18°C以下，金柑開花即受到抑制，顯示低溫於金柑開花所扮演的角色迥異於對大果柑橘之促進效應。
為探討不同調虧灌溉（RDI）對盆栽金柑生長之影響，於枝梢停梢後進行兩週不同灌溉處理。處理分別為灌溉有效水75%之對照組、灌溉有效水55%之RDI 1處理組及灌溉有效水35%之RDI 2處理組。在控水兩週後（stage B），RDI 2處理組之葉片水勢顯著下降，並具最高之整合葉片水勢指數，顯示其葉片所遭受之水分逆境程度最大。在控水兩週後，RDI 2處理組之葉片之淨光合作用速率、Fv/Fm及Fv’/Fm’值亦顯著低於其他處理組。然而，RDI 2處理組葉片之生長指數於復水兩週後表現出明顯之補償效應。RDI 2處理組枝條具明顯之開花能力，其每節位開花率為50％，顯著高於對照組及RDI 1處理組。
金柑一年中可多次抽梢並多次開花，枝梢之管理，宜保留生育季較為充足之一、二次梢，而於高溫下萌發，因快速生長而早熟之枝條應儘早疏除，以避免養分消耗。金柑於日/夜溫25/18°C以上即明顯促進開花，因此於金柑盆栽生產上，可利用不同時期之修剪模式，調節產期。另外於停梢後，施予兩週低水量（有效水35%）之調虧灌溉，可明顯抑制枝條營養生長勢，提高開花率並集中花期，於盆栽金柑生產上，可有效增進盆栽品質並達節水目的。

關鍵字

金柑 ； 物候 ； 枝梢 ； 開花 ； 溫度 ； 調虧灌溉

並列摘要

The objectives of this study were to compose the complete growth information of kumquat trees (Fortunella margarita (Lour.) Swingle) trees grown in the subtropical conditions of Taiwan and establish functional operation for flowering regulation which might propose crucial strategies for improvement in kumquat industry. The new buds of the second, third, and forth flushes sprouted in mid May, early July, and early Sep., which almost 70-80, 112-122, and 168-178 days after the first flush sprouted, respectively. Flowering potential of the flowering rate of shoot and flower number per shoot was decreased as flush sequences increased. The shoot flowering potential of the first flush, exhibited 4 peaks in 2010 and 5 peaks in 2011. In experiment of 2011, the fruiting potential displayed on the first flush shoot, sprouted in March; besides, a higher proportion of successful fruit set was observed on shoots which fruitlets were formed from flowers of the second flowering sequence, bloomed in mid July.
Temperature treatments included T 25-32, T 17-25, T 22, and T 18. The T 25-32 treatment exposed trees to the day/night temperatures of 25/18°C for 2 weeks, followed by 28 weeks at 32/25°C. T 17-25 was 4 weeks of exposure to 17/10°C followed by 26 weeks at 25/18°C. T 22 and T 18 were for 22/18°C and 18/13°C, respectively, for the entire duration of the experiment. Control trees were placed in a plastic greenhouse under the conditions similar to the natural environment. The kumquat trees exposed to the high-temperature environment of 32/25°C showed the more frequent and speedy sprouting of new buds, but induced the earlier termination of shoot elongation growth, resulting in decreased vegetative growth. The temperature treatments at lower than 22°C suppressed the new shoot production but increased the shoot growth period, resulting in increased shoot length and diameter. Temperatures higher than 25/18°C readily induced flowering, with flowering being advanced under the higher temperature conditions such as 32/25°C. However, flowering was substantially inhibited under the temperature conditions lower than 22/18°C, indicating the negative role of relatively lower temperatures on flowering of kumquat trees.
Three treatments were implemented for two weeks as shoot elongation terminated, that is, Control, RDI 1, and RDI 2, which irrigated trees with 75%, 55%, and 35% available water, respectively. After withholding water for two weeks (stage B), leaf water potential of the RDI 2 group decreased significantly, and the RDI 2 group exhibited the highest integrated leaf water potential index, which indicated the highest stress level that leaves encountered. Results of the net CO2 assimilation rate (Pn), Fv/Fm, and Fv’/Fm’ of the RDI 2 group also significantly decreased after trees were conducted water withholding for two weeks; however, all growth parameters exhibited an obvious re-watering compensation effect after water recovery. Trees of the RDI 2 group exhibited an obvious flowering potential on shoots. The flowering rate of each node in RDI 2 exhibited the highest average rate of 50%, which significantly differed from those of the Control and RDI 1 groups did. The kumquat trees of the RDI 2 group efficiently altered shoot growth phases and obviously concentrated the flowering period, which offers a valuable water management approach for high-quality potted kumquat production.

並列關鍵字

kumquat (Fortunella margarita (Lour.) Swingle) ； phenology ； flush ； flowering ； temperature ； regulated deficit irrigation (RDI)

參考文獻

9. Chang, Y.S. 1986. The physiology flowering in citrus. J. Chinese Soc. Hort. Sci. 32: 71-84

10. Chen, R.Y., J.P. Huang, and M.J. Tsai. 2010. The effect of the kumquat (Fortunella margarita Swingle) peel extract on the inflammatory biomarkers associated with cardiovascular risk. Taiwanese J. Agri. Chem. Food Sci. 48:112-119.

54. Lai, Y.T. and I.Z. Chen. 2007. Effect of heavy pruning on calamondin (Citrus microcarpa) flower bud formation and flowering. J. Taiwan Soc. Hort. Sci. 55: 185-194.

1. Abbot, C.E. 1935. Blossom-bud differentiation in citrus trees. Amer. J. Bot. 22: 476-485.

4. Boyer, J.S. 1971. Recovery of photosynthesis in sunflower after a period of low leaf water potential. Plant Physiol. 47: 816-820.