套袋對文旦果實生長、品質與袋內溫度的影響

Effect of Bagging on Fruit Growth and Quality of 'Wentar' Pummelo (Citrus grandis (L.) Osback) and the Temperature Inside the Bag

為探討不同時期套袋對文旦果實生長與品質的影響，五月下旬起，每一個月套袋一次，至七月底止，共三次。第一次套白色紙袋，第二次及第三次分別套白色及棕色紙袋，不套袋者為對照。八月中旬至下旬調查袋內之溫度變化。日間袋內之氣溫較外界氣溫可提高9°C，夜間袋內與外界之氣溫幾無差異。日間袋內溫度變化明顯地受到日照強度的影響。日間袋內相對溼度較袋外低5%至10%，夜間袋內與袋外之差異甚小。就整個試驗期間比較，最早套袋者，果實之生長率最低，但未達顯著差異。採收後一週進行品質分析。結果顯示果實之主要特性包括體積、果重、果形指數、比重、皮厚、果皮質地、糖度、風味 等在各處理間均未達顯著差異。果皮顏色之差異主要為明度（L值），套白色袋者較套棕色袋或不套袋者明度大，達到極顯著的差異。但此一顏色差異甚有限，並不易由肉眼察覺。

To investigate the effect of bagging on fruit growth and quality of 'Wentan' pummelo, the fruits were bagged with white or brown paper bags on 24th May, 26th June and 25th July. Fruit sizes were measured on each days of bagging and on September 11th after the fruits were harvested. Temperatures inside the bags in different positions of the canopy were recorded from middle to late August. The results showed that fruit characters including size, weight, specific gravity, fruit shape, rind thickness, rind texture, sugar content and flavor were not significantly different among the treatments. In day time the temperature differences inside and outside the bags can be as high as 9°C. The differences of relative humidities were 5 to 10 %. The temperatures increased inside the bags were related to the intensity of solar radiation. The growth rate of fruits which bagged earliest was lowest, but that was not significantly different among the treatments. The color of fruit peel was analyzed on one day and one week after harvesting. L values of the fruits bagged with white bag were higher than those of the fruits bagged with brown bag or without bagging, but the a and b values were not significantly different among the treatments. These results explained that the fruits without bagging were a little dark greener than the other treatments, but the difference was not much that it can not be visually distinguished.