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標題: | 非洲芙蓉扦插繁殖與開花生理之研究 Studies on Cutting Propagation and Flowering Physiology of Dombeya wallichii |
作者: | Ying Liu 劉影 |
指導教授: | 葉德銘(Der-Ming Yeh) |
關鍵字: | 容器大小與修剪,插穗型式,非洲芙蓉,?花,激勃素,光週,溫度, container size and pruning,cutting type,Dombeya,flowering,gibberellin,photoperiod,temperature, |
出版年 : | 2019 |
學位: | 碩士 |
摘要: | 非洲芙蓉[Dombeya wallichii (Lindl.) K.Schum.]為錦葵科之觀賞花木,花型獨特,芬芳艷麗,應用於盆花或景觀佈置,深受歡迎,然而其自然花期局限於冬季。本論文探討非洲芙蓉扦插繁殖,並研究溫度、光週期、容器大小與修剪及噴施GA3等因素對其開花之影響,以期調整花期,增加其應用價值。
本論文第一部分探討非洲芙蓉扦插發根率,於11月初取15 cm長不帶葉片之綠枝、半硬枝及硬枝插穗扦插,結果28天後所有插穗皆存活,但均無發根;另取15 cm長,帶頂芽及葉片之綠枝、不帶葉片之半硬枝及硬枝插穗扦插,結果28天後所有插穗皆存活,但僅帶頂芽及葉片之綠枝插穗發根。於11月初另取帶頂芽及兩片葉的綠枝,分別剪成5、10、15或20 cm長之插穗扦插,結果28天與56天後,所有長度之插穗皆發根,但長5 cm之插穗發根率及發根數略低。非洲芙蓉的扦插發根包含了皮部發根及癒傷組織發根。 本論文第二部份探討溫度及日長對非洲芙蓉開花之影響,於5月初取高度20 cm,帶兩片葉之扦插苗,置於日/夜溫為15/13、20/15、25/20、30/25或35/20℃的人工氣候室,處理84天後以30/25℃處理植株最高,枝條最長,每枝條葉片數最多。處理119天後以35/30℃處理植株的葉片最小,新生枝條莖徑最細。15/13℃處理植株的葉片最大螢光值(maximum fluorescence, Fm)及PSⅡ最大光化學效率(maximum quantum efficiency of photosystem Ⅱ photochemistry, Fv/Fm)最低;35/30℃處理植株的葉片光化學猝熄(photochemical quenching, qP)、非光化學猝熄係數(non-photochemical quenching coefficient, qN)以及非光化學猝熄(non-photochemical quenching, NPQ)下降,且其淨光合作用速率(net CO2 assimilation rate, Pn)顯著低於其他溫度處理。植株於15/13℃與20/15℃處理112天後現蕾,花下葉片數分別爲7.9與9.1;25/20℃處理者119天現蕾,花下葉片數為12;30/25℃與35/30℃處理182天後仍未形成花芽。結果顯示15/13℃處理有利非洲芙蓉之花芽形成,而25/20℃已接近非洲芙蓉花芽形成的上限溫度。 另於9月將原本於30/25℃與35/30℃處理18週之非洲芙蓉植株半數移入15/13℃低溫中,移入15/13℃之植株於35天後皆可見花蕾,而持續於30/25℃與35/30℃高溫環境之植株則未產生花蕾。可見高溫前處理不影響日後低溫下非洲芙蓉的花芽形成。 於12月初將具直徑2.1±0.1 cm花芽之非洲芙蓉植株移入人工氣候室接受不同溫度處理,結果顯示15/13℃、20/15℃及25/20℃皆有利花芽發育,且25/20℃處理者花序數最多,開花最早; 30/25℃不利非洲芙蓉花芽發育,處理50天後有38.6%消蕾。非洲芙蓉自花芽直徑為2.1±0.1 cm發育到花萼顯色及開花的基礎溫度(base temperature, Tb)分別為1.54及1.82℃,計算非洲芙蓉自花芽直徑為2.1±0.1 cm發育至花萼顯色階段,約需396-487℃d,而發育至開花階段,約需556-645℃d。 於8月中旬取帶6片展開葉的非洲芙蓉綠枝扦插苗置於24/14℃、每日以PPF (photosynthetic photon flux)約300 μmol·m-2·s-1人工光源照光8 h的環境中經7、14、21、28或35天後,移入紅:藍=8:1之混合LED白光燈盤提供PPF約150 μmol·m-2·s-1的16 h長日環境。結果顯示隨著短日循環次數增多,植株新長之花下葉片數及新長之節間長減少,花芽數及初始花芽直徑則增加,推測非洲芙蓉為非絕對性短日植物。 本文第三部份探討容器大小與修剪對非洲芙蓉生長及開花之影響,於11月初將非洲芙蓉樹苗修剪至30、60、90、120 cm高,僅保留主幹。並定植於47、32、18 L三種大小的容器中,處理150天後,植株高度與容器尺寸及修剪高度成正比;處理210天後之植株高度增加量與容器尺寸成正比但與修剪高度成反比。容器處理255天後植株側枝數不受容器尺寸影響,但隨修剪高度增加;側枝長度與容器尺寸成正比但與修剪高度成反比,側枝葉片數亦同。處理60天後,大容器栽培有利植株形成花芽,但修剪高度則無影響。 本論文第四部份探討勃激素(GA)對非洲芙蓉開花之影響,於10月初在非洲芙蓉未現蕾枝條葉片上噴施2500 mg·L-1或5000 mg·L-1 的GA3溶液,可提早7天現蕾,但對花萼顯色天數及開花天數無影響。GA3處理後14天有枝條現蕾,而未噴施GA3之對照組晚1週始現蕾。每枝條花芽數、花序直徑及花序梗長度於處理間均無顯著差異。 於1月自然花期,於非洲芙蓉枝條自頂端數起第三個腋生花苞(直徑4.4±0.1 cm,花序梗長12.1±0.3 cm)上噴施250或500 mg·L-1的GA3溶液。可讓花苞提早約3-4天達到花萼顯色階段,但對開花天數無影響。 Dombeya wallichii (Lindl.) K. Schum. is a woody ornamental species in the Malvaceae family. The attractive flower pattern and fragrance make it a popular choice for container gardending or landscape layout. However, its natural flowering period is limited to winter. In this thesis, methods for cutting propagation was evaluated, and environmental factors, e.g. temperature and photoperiod as well as cultural factors, e.g. container size, pruning, and GA3 spray were investigated to document the mentioned variables on plant growth and flowering of Dombeya in order to increase its commercial potential. In the first part of this thesis, cutting propagation of Dombeya was evaluated. In the fist trial, defoliated softwoods, semi-hardwoods and hardwoods were trimmed to a length of 15 cm and were inserted into propagation medium in early November. All the cuttings survived after 28 days but none rooted. In the second trial, leafy terminal softwoods and defoliated semi-hardwoods and hardwoods were trimmed to a length of 15 cm for cutting. All survived after 28 days but only leafy softwoods successfully rooted. In the third trial, leafy terminal softwoods were trimmed to 5, 10, 15 or 20 cm for cutting. All culltings rooted after 28 days and 56 days. Low rooting rate and root number were recorded in the 5 cm cuttings . Rooting types of Dombeya wallichii included rooting from barks and callus. In the second part of this thesis, temperature and photoperiod effect on Dombeya flowering were investigated. Single stemmed Dombeya plants were heading to a height of 20 cm with two fully expanded leaves and grown in phytotrons, under natural daylength conditions in May, with day/night temperatures of 15/13℃, 20/15℃, 25/20℃, 30/25℃ or 35/30℃. Plants at 30/25℃ after 84 days were most vigorous, with the longest shoots and the greatest number of leaves per shoot than plants subjected to other temperatures. Plants at 35/30℃ after 119 days had the smallest leaves and diameter of new shoots. The maximum fluorescence (Fm) and maximum quantum efficiency of photosystem II photochemistry (Fv/Fm) of the mature leaf on plants at 15/13°C were the lowest, and the photochemical quenching (qP), non-photochemical quenching coefficient (qN) and non-photochemical quenching (NPQ) of the leaf on plants at 35/30°C declined. Also, leaf net photosynthesis rate (Pn) of plants grown at 35/30°C was significantly lower than other temperature treatments. Flower buds were observed on plants after 112 days at 15/13℃ or 20/15℃, with 7.9 and 9.1 leaves below the first inflorescence, respectively, and on plants after 119 days at 25/20℃, with 12 leaves below the first inflorecence. No flower buds were observed on plants at 30/25℃ or 35/30℃ for 182 days. The results indicated that 15/13℃ is beneficial for flower formation of Dombeya, and 25/20℃ is likely the upper limit temperature for flower formation. In the second temperature trail, half of the plants originally grown at 30/25℃ and 35/30℃ for 18 weeks beforetransferred to 15/13 °C in early September produced flower buds after 35 days, while those remained at high temperatures did not produce any flower buds, suggesting that high temperature pretreatment did not affect flower formation of Dombeya at low temperatures. In the third temperature trail, Dombeya with 2.1±0.1 cm flower buds were transferred to phytotrons in early December. Results showed that within the range of 15/13°C to 25/20 °C, warm temperatures were beneficial to flower development and plants grown at 25/20 °C flowered earlier and the number of inflorescences was the highest. However, 30/25°C was not suitable for flower development, as 38.6% buds aborted after treatment for 50 days. Base temperatures of 2.1±0.1 cm flower buds developing to calyx visibility and flower were 1.54°C and 1.82°C, respectively. And the thermal time of 2.1±0.1 cm flower buds reaching to calyx visibility stage and flower stage were about 396-487℃d and 556-645℃d, respectively. In the photoperiod trial, rooted softwood cuttings with six expanded leaves were placed at 24/14°C in mid- August and illuminated with a photosynthetic photon flux (PPF) of 300 μmol·m-2·s-1 for 8 h daily. After 7, 14, 21, 28, and 35 days, plants were transferred to long day environment and lighted with a PPF of 150 μmol·m-2·s-1 provided with a mixed LED white light panel with red : blue=8:1 for 16 h daily . Results showed that the increase in the number of short-day cycles decreased the number of newly-grown leaves below the flowers and the length of newly-grown internodes , while increased the number of flower buds and the initial flower bud diameter. The result indicated that Dombeya is a facultative short-day plant. The third part of this thesis reported the effects of container size and pruning severity on growth and flowering in Dombeya. Saplings were trimmed to 30, 60, 90, or 120 cm tall, leaving only the trunk and planted in 47, 32, or 18 L containers in early November. Plants grown in 47 L containers after 150 days were the highest, and the plant height decreased with the decrease of the pruning height. More plant height increment were observed in plants grown in large containers or pruned to 30 cm high after 210 days, and the plant height increment reduced as container size decreased or pruning height increased. After 255 days of treatments, container size had no effect on number of shoots, but number of shoots increased as the pruning height increased from 30 to 120 cm. Shoot length increased with increasing container size or decreaing prun height. Similar reaction was also observed on number of leaves per shoot. More plants grown in large containers produced flower buds after 60 days, while prun height had no effect on it. After 120 days of treatment, the proportion of plants with flower buds were higher in which grown in large containers, and lower in those grown in small containers. Flowering rate of plants grown in small containers was significantly lower after 183 days. The final part of this thesis investigated the effect of gibberellin on flowering of Dombeya. In early October, 2500 mg·L-1 and 5000 mg·L-1 of GA3 solution were sprayed on the leaves of Dombeya shoots without flower buds. Flower buds were visible 7 days earlier on shoots with GA3 treatment than the un-sprayed control but days to calyx visibility and days to flowering were not affected by GA3. Flower buds were visible after GA3 treatment for 14 days, and the control group without GA3 treatment had visible flower buds 1 week later. There was no significant difference in number of flower buds, inflorescence diameter and peduncle length between treatments. In the natural flowering period, the third axillary flower bud (diameter 4.4±0.1 cm, peduncle length 12.1±0.3 cm) from the top of Dombeya was sprayed with 250 and 500 mg·L-1 GA3 solution in January. Results showed that GA3 treatment allowed the flower buds to reach the calyx visibility stage about 3-4 days earlier, but had no effect on the days to flowering. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/7308 |
DOI: | 10.6342/NTU201901427 |
全文授權: | 同意授權(全球公開) |
顯示於系所單位: | 園藝暨景觀學系 |
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