| 摘要： 本試驗之目的首先在調查絲瓜果實之生長發育及生理，以訂定適當之採收成熟度，其次尋求最適合貯存絲瓜的溫度條件，最後以絲瓜為材料，探討絲瓜在寒害過程中各種理化及組成分之變化，建立供偵測寒害的指標。‘香水’絲瓜果實發育期間由果實的鮮重、長和寬之變化均呈現單S型的生長曲線；而果實於花後11至15天其全可溶性糖逹到最高，此時期為最佳採收期。絲瓜為低溫敏感作物，在低溫貯藏時會造成寒害，而使其喪失商業價值，本試驗結果顯示絲瓜果實在6℃及以下溫度貯放即有可能發生寒害。果實的失重率及葉綠素光化學活性會因不同貯藏溫度而有差異，通常會隨著溫度的下降，其值分別會跟著增加和減低。絲瓜果實若貯存在低溫再移溫時，其呼吸率和乙烯釋放率皆有上升現象，且與寒害之嚴重程度成正相關；並隨著時間延長而有加劇之情形，在1℃至6℃貯藏二週後，呼吸率和乙烯釋放率上升後均無法再下降。故可利用失重率、呼吸率、乙烯釋放率和葉綠素光化學反應來判別寒害，但其中以葉綠素光化學反應，在測定上最為簡便和快速，故為較佳的指標。 另外，利用PE袋包裝可以降低寒害發生，其中以打孔PE袋包裝及袋內加乙烯和二氧化碳吸收劑者較佳，且3℃較1℃者效果明顯。以不同氧濃度處理絲瓜果實時，若氧低於5%以下反而會加劇其寒害。絲瓜果實採後將其貯藏於9℃加濕通風條件下，其寒害症狀、腐敗率等，均在貯存後第4週時才發生；且其碳水化物在貯藏期間並無明顯變化，故‘平順’絲瓜在9℃下之貯藏壽命可長逹3週。In the experiment a survey was conducted for the study of the growth, development and physiology aspect of smooth loofah fruit. From the data it is possible to determine the optimum stage for harvest. Endears were also made to find out the best storage temperatures for this smooth loofah fruit. Last but not least, attempts were made to use smooth loofah as study materials for the understanding of the effects of low temperatures on the physical, chemical and compositional changes of the spices. Hopefully an index for detecting the adverse effect of the cold could be found. During the developmental stage, the growth curves of the ‘Perfume’ smooth loofah fruits were odd enough to be single sigmoid in terms of fresh weight, length and width. According to the highest soluble sugar in fruits, the optimal harvest stage of smooth loofah is on 11-15th days after anthesis. Smooth loofah fruits is sensitive to low temperatures. It suffers when kept at low temperatures and will soon lose its economic value. As data indicated that smooth loofah stored at a temperature lower than 6℃ would show sign of chilling injury. Generally speaking, the rate of losing fruit weight as well as chlorophyll photochemical activity varied with temperatures. As a rule, these conditions worsened as the temperature plummeted. When chilled smooth loofah fruit was moved to a higher temperature, its respiration rate and ethylene production rate would increase in proportion to the severity of the damage brought about by the cold. And it became more devastating as the duration of cold spell lengthened. After two weeks at temperatures ranging from 1℃ to 6℃, the elevated respiration rate and the heightened ethylene content became irreversible. These changes, that is, the respiration rate, the ethylene production and the chlorophyll photochemical activity, all can serve as index of the chilling injury. Of the three, the chlorophyll photochemical activity is considered to be the best because the analysis of it is quick and easy. In addition, smooth loofah fruits wrapped in polyethylene bags could alleviate the harmful nature of the chilled. Perforated polyethylene bags or sealed polyethylene bags containing or filled with ethylene absorbents and carbon dioxide absorbents were better than the plain ones. They demonstrated their clear-cut superiority at 3℃ and only to a leaser extent at 1℃. As for the protective ability of oxygen concentrations, oxygen level below 5% exacerbated the wrath of the chilled. The damaging effects became evident when the harvested smooth loofah fruit was kept at 9℃ in a moist condition to its fourth weeks. During this period little changes had happened to the carbohydrates of smooth loofah fruit. Hence, the storage life for ‘Plain Sailing’ smooth loofah at 9℃ was three weeks. |
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