可溶性醣提升文心蘭切花採後品質

Abstract

本研究添加不同可溶性醣類 (蔗糖、葡萄糖、果糖) 於文心蘭切花瓶插液中，探討可溶性醣類添加對文心蘭切花之保鮮、植體內碳水化合物、乙烯生成量及抗氧化酵素之影響，期望能獲得具較佳瓶插壽命之切花採後保鮮方法。 添加蔗糖、葡萄糖、果糖於瓶插液中，文心蘭Oncidesa Gower Ramsey ‘Honey Angel’切花相較於未加醣類之對照組可延緩切花老化，其中50 mg·L-1 glucose + 200 mg·L-1 8-HQS瓶插處理之觀賞壽命可達20天，相較於200 mg·L-1 8-HQS對照組延長4天觀賞日數，同時維持切花水分平衡，顯著延緩切花萎凋速率。於兩次的試驗結果發現單醣 (葡萄糖、果糖) 之處理相較於雙醣 (蔗糖) 具有較佳之保鮮效果。 添加醣類於瓶插液中，可提升文心蘭花苞內果糖與葡萄糖含量，協助花苞順利展開。另外，對照組小花之可溶性醣含量於萎凋期間持續下降，瓶插液添加可溶性醣後使得花朵維持較高含量的可溶性醣，具延長花朵壽命之效果。 不同濃度乙烯處理皆降低文心蘭切花最大完全展開小花數，顯著減少觀賞品質，其中1 µL·L-1乙烯減少約31.5%花朵數，而於乙烯環境下處理50 mg·L-1 glucose + 200 mg·L-1 8-HQS瓶插液可提升瓶插初期瓶插液吸收量、延緩相對鮮重下降，並提升花苞開放程度。然而，葡萄糖添加於瓶插液對切花乙烯生成量並無顯著影響。 文心蘭於瓶插初期主要以過氧化氫酶 (CAT) 與抗壞血酸過氧化酶 (APX) 作為主要抗氧化酵素，於瓶插後期老化徵狀 (花瓣失水、小花梗黃化) 出現時，超氧化物歧化酶 (SOD) 為重要抗氧化酵素。於瓶插液中添加葡萄糖後，SOD活性自29.87 unit·g-1增加至36.63 unit·g-1，CAT活性由0.09 unit·g-1增加至0.11 unit·g-1，提升文心蘭花瓣清除活性氧物質能力，延緩細胞氧化逆境失衡造成的老化現象。

The purposes of this study were to investigate senescence phenomenon, carbohydrates changes, ethylene production, and antioxidant enzymes activities of Oncidesa cut flowers after treated with soluble sugars (sucrose, glucose, and fructose). We hope to get a better postharvest fresh-keeping method of cut flowers and understand the physiology of Oncidesa cut flowers treated with soluble sugars. Oncidesa cut flowers were treated with soluble sugars (sucrose, glucose, fructose) in vase. Adding soluble sugars in vase significantly prolonged vase life. The vase life of Oncidesa treated with 50 mg·L-1 glucose + 200 mg·L-1 8-HQS was up to 20 days. Compared with 200 mg·L-1 8-HQS, the vase life extended by 4 days. Also, it maintained water balance of the cut flowers, and significantly slowed down wilting rate of cut flowers. The results of two experiments demonstrated that monosaccharides (glucose, fructose) had a better preservation effect than disaccharides (sucrose). During the vase days of Oncidesa cut flowers, the addition of sugars greatly increased the contents of fructose and glucose in the flower buds, helping them to develop. Compared with control, in which soluble sugars contents in the florets continued to decrease, soluble sugars content maintained high in the florets of cut flowers treated with sugars in vase. Thus, sugar-added treatments have the effect of prolonging vase life. Ethylene treatments at various concentrations reduced the number of fully expanded florets of Oncidesa and significantly reduced cut flower quality. Among the treatments, 1 µL·L-1 ethylene reduced the number of florets by about 31.5%, while 50 mg·L-1 glucose + 200 mg·L-1 8-HQS increased the absorption of solution at the beginning of vase days, delayed the drop of relative fresh weight, and increased the opening of flower buds. However, the addition of glucose in vase has no significant effect on reducing ethylene production of cut flowers. In the early vase days, Oncidesa mainly used catalase (CAT) and ascorbate peroxidase (APX) as the main antioxidant enzymes. At the late period of vase days, when senescence symptoms (petal dehydration or pedicel yellowing) appeared, superoxide dismutase (SOD) was an important antioxidant enzyme. After glucose was added in vase, the activity of SOD increased from 29.87 unit·g-1 to 36.63 unit·g-1 and CAT activity increased from 0.09 unit·g-1 to 0.11 unit·g-1. Also, they enhanced the ability of removing reactive oxygen species, and delayed senescence symptoms caused by oxidative stress.