長壽花之切花與插穗貯運保鮮技術

Abstract

長壽花為燈籠草屬(Kalanchoe)多年生肉質草本植物，近年已發展切花品種，觀賞壽命長為其優勢，讓長壽花切花與插穗具有內外銷發展潛力。目前空運試銷至日本拍賣市場之長壽花切花貯後品質明顯下降，而目前較少研究調查長壽花切花與插穗之保鮮技術。本研究探討瓶插液添加殺菌劑或糖類對長壽花‘Fabulous Yellow’切花瓶插品質之影響，模擬11℃海運14天、貯運前處理gibberellic acid (GA4+7)或17-(allylamino)-17-demethoxygeldanamycin (17-AAG)對長壽花‘Fabulous Yellow’切花貯後品質之影響，貯運期間乙烯及1-MCP前處理對長壽花‘Fabulous Yellow’切花之保護效果。調查長壽花品系P134與品系P159貯藏適溫與貯藏適期，以及17-AAG前處理對提升插穗耐貯性之效果。 長壽花‘Fabulous Yellow’切花於24℃室內環境瓶插期間達最大小花開花率約56%，瓶插壽命約33天。瓶插液添加稀釋濃度250 – 1000 μL·L-1之12%次氯酸鈉溶液，沒有提升小花開花率、無延長瓶插壽命之效果，長期瓶插於次氯酸鈉溶液會提升葉片黃化率。瓶插於含10 - 30 g·L-1葡萄糖或蔗糖溶液，有延緩葉片黃化之效果，但不會促進小花開放亦無法延長瓶插壽命。 模擬11℃海運暗貯14天出庫後長壽花‘Fabulous Yellow’切花提早出現葉片黃化，小花消蕾率快速上升達50%以上，小花最大開花率僅約46%，瓶插壽命19天顯著低於未經過貯藏之處理。貯運前吸水24 h能有效減少小花苞消蕾，恢復貯後瓶插壽命至34天。貯前對花序噴施25 - 100 μM GA4+7，隨施用濃度越高貯後小花開花率越高可達88%，並延長切花瓶插壽命至44天。前處理100 nM 17-AAG雖能延緩貯後葉片黃化但不會提升小花開花率與瓶插壽命。 模擬海運期間外施0.8 - 3.7 μL·L-1乙烯，受到環境乙烯影響長壽花‘Fabulous Yellow’切花出庫當天小花開花率降至0%。離開乙烯環境1 - 2週後部分小花苞能繼續綻放，但隨環境乙烯濃度越高貯後小花最大開花率由未施乙烯處理之62%降至26%，瓶插壽命由37天減少至13天。以900 nL·L-1 1-MCP前處理24小時能克服14天貯運期間3.8 μL·L-1乙烯造成之小花萎凋與小花苞消蕾，貯後小花開花率由未施1-MCP處理之11%提高至65%，瓶插壽命由12天延長至36天，有效維持‘Fabulous Yellow’切花經乙烯貯後之觀賞品質。 長壽花品系P134插穗以5℃ - 20℃貯藏14天內對貯後SPAD-502計讀值、Fv/Fm與發根表現沒有負面影響；而品系P159插穗對低溫較敏感，貯藏溫度越低發根表現越差，建議貯藏於15℃以上。兩品系之插穗貯藏21天後SPAD-502計讀值、Fv/Fm與發根表現顯著下降，且有明顯黃葉與落葉情況。以15℃ - 20℃貯藏7至14天品系P134與159插穗貯後發根數、根長與根乾重顯著比未貯藏者多。對低溫較敏感之品系P159插穗以1 μM 17-AAG前處理，能促進於5℃貯藏後之發根表現，而17-AAG前處理對品系P134插穗貯後品質並沒有正面影響。扦插前插穗鮮重與莖徑之參數可作為長壽花品系P134插穗發根品質之參考依據，當節數三節插穗之鮮重由3.8 g減少至2.0 g，根乾重隨之顯著由25.1 mg 減少至12.1 mg。 由本研究可得知瓶插液中添加次氯酸鈉或糖類無法提升長壽花切花之開花率與瓶插壽命，而對於長壽花切花與插穗之採後處理，我們提供以下幾項方式有助於提升貯後品質：模擬海運11℃暗貯14天前噴施100 μM GA4+7能提高貯後小花開花率達88%，若於貯運期間暴露於乙烯環境，可使用900 nL·L-1 1-MCP前處理24小時克服環境乙烯造成小花萎凋與小花苞消蕾。長壽花品系P134與P159插穗貯藏上限為14天，以15℃ - 20℃貯藏7至14天插穗貯後發根數、根長與根乾重顯著比未貯藏者多。

Newly released kalanchoe (Kalanchoe blossfeldiana) cut flower cultivars, known for their long-lasting characteristics, exhibit promising potential in novelty export markets. However, kalanchoe cut flowers are currently transported under dry and dark conditions, which resulted in reduced floret anthesis and post-storage quality. Information on the postharvest of kalanchoe cut flowers and cuttings is presently limited. This study aimed to establish the storage and preservation technology for kalanchoe cut flowers and cuttings. Results show that in indoor environments at 24°C, the vase life and anthesis percentage of kalanchoe ‘Fabulous Yellow’ cut flowers were approximately 33 d and 56%, respectively. Vase life and anthesis percentage of florets remained unaffected by vase solutions containing 250 - 1000 μL·L-1 sodium hypochlorite, or 10 - 30 g·L-1 sucrose or glucose. However, vase solution with sodium hypochlorite increased the percentage of leaf chlorosis, while vase solution with sugar decreased it. During simulated storage and transportation, kalanchoe ‘Fabulous Yellow’ cut flowers were stored in dark at 11°C for 14d. Compared to the unstored treatment, the percentage of aborted buds increased to more than 50%, the maximum flowering percentage of florets was only about 46%, and the vase life significantly reduced to 19d. Pulsing the cut flowers with water for 24 h before storage effectively reduced the percentage of aborted buds and prolong the vase life to 34 d after simulated storage. Here, we examined the effect of gibberellic acid (GA4+7) and 17-(allylamino)-17-demethoxygeldanamycin (17-AAG) on post-storage quality in ‘Fabulous Yellow’ kalanchoe cut flowers. Pretreatment with a single spray of 25 - 100 μM GA4+7 on the florets before the dark storage decreased the aborted bud percentage and increased the anthesis percentage. A spray of 100 μM GA4+7 resulted in the highest anthesis percentage of 88% and 76% for the main and lateral inflorescences, respectively, and extended the vase life to 44 d. However, pretreatment with 100 nM 17-AAG could delay leaf chlorosis after storage, but did not improve the anthesis percentage and vase life. When exposed to 0.8 - 3.7 μL·L-1 ethylene during 14 d of simulated dark storage at 11°C, the anthesis percentage of kalanchoe ‘Fabulous Yellow’ cut flowers dropped to 0% on the day of delivery. However, the anthesis percentage increased after leaving the ethylene environment for 1-2 weeks. Compared to storage without ethylene, exposure to 3.7 μL·L-1 ethylene decreased the maximum anthesis percentage from 62% to 26%, and the vase life decreased from 37 d to 13 d. Pretreatment with 900 nL·L-1 1-MCP for 24 h protected the florets during stored with 3.8 μL·L-1 ethylene for 14 d, which increased anthesis percentage from 11% to 65% and extended the vase life from 11d to 36 d. Kalanchoe strain P134 cuttings could be stored at 5°C - 20°C for 14 d, while the strain P159 cuttings were more sensitive to low temperatures and should be stored at 15°C - 20°C. Both strain P134 and P159 cuttings could not be stored for more than 21 d, resulting in a significant decrease on SPAD-502 value, chlorophyll fluorescence (Fv/Fm) and rooting. Notably, the root number, root length, and root dry weight of strain P134 and P159 cuttings stored at 15°C - 20°C for 7d to 14 d were significantly higher than those without storage. Pretreatment with 1 μM 17-AAG promoted the rooting of strain P159 cuttings after 5°C storage, while it had no positive effect on the post-storage quality of strain P134 cuttings. The fresh weight and stem diameter of cuttings before planting could be the quality parameters of kalanchoe strain P134 cuttings. Cuttings with three nodes and fresh weight of 3.8 g and 2.0 g, resulted in root dry weights of 25.1 mg and 12.1 mg, respectively. In conclusion, adding sodium hypochlorite or sugars to the vase solution did not improve the anthesis percentage and vase life of kalanchoe ‘Fabulous Yellow’ cut flowers. A single spray of 100 μM GA4+7 pretreatment resulted in the highest anthesis percentage of 88% after dark storage at 11°C for 14 d. Furthermore, if exposed to ethylene during the storage, pretreatment with 900 nL·L-1 1-MCP for 24 h could effectively maintain the post-storage quality of kalanchoe cut flowers. Finally, for better rooting, kalanchoe strain P134 and P159 cuttings should be stored for 7d to 14 d at 15°C - 20°C. These findings establish the fundamental postharvest behavior of kalanchoe cut flowers and cuttings and provide a practical method to maintain post-storage quality.