秋冬香蕉發育期間含水分與乾物重之變化

The Changes of Water and Dry Weight Contents in Autumn and Winter Banana during Different Stages of Fruit Development

冬蕉自抽穗後12日開始測定果實發育及乾物重變化，顯示10-50日期間內對果皮營養與耐藏能力有極密切關係。在100日收穫，果皮具最大乾物重（密度）。120日收穫則產量較高。果皮發育期間遠較果肉為短，二者之比較約為1:3。果皮及果肉水分急劇減低後，隨之乾物呈現顯著增加。關於香蕉植株及果實所含水分，在同一季節中均有一定量，在不同季節中則有變化。不同品種春蕉及秋蕉水分含量之差北蕉為7%，矮蕉為5.98%。南部一般能灌溉及雨季無長期積水蕉園，缺水及排水問題對香蕉生育所引起之不良影響不至嚴重。

A. The development of winter banana fruit: (1) The reasons causing the skin of banana rapidly increasing water content during 10-30 days after fruit thinning are the transevaporation osmotic withdrawal and cell expansion to meet the physiological requirements But there are little increase of dry matter during this period. During 30-40 days the water content decreases rapidly, the concentration of cytoplasm and dry matter increase, therefore the thickness of skin is increased significantly. The increase of dry matter, fresh weight, fruit length and thickness of skin during 10-50 days after thinning is the most important period of development of skin tissue which might affect the storage greatly of banana fruit. (2) During 100-120 days after thinning, the dry matter, fresh weight and the thickness of skin decrease but the water content is increased. (3) The water content of skin is 19% higher than pulp in winter-banana. It would be an important relationship between water content of skin and the rottenness of banana. (4) The increase of dry matter and fresh weight of pulp during 10-90 days is faster than 90-100 days after shooting. The period of formation of pulp is longer than that of skin which is in 3:1 ratio of time. (5) The water content of skin and pulp has the tendency of decrease just before increasing dry matter, and which cause increasing the concentration of cytoplasm. (6) If we produce winter banana in Feb, the yield is affected by low temperature during fruit developing period of 80-100 days after shooting. So we suggest that selecting warmer area to grow winter-banana will get higher yield. (7) Among four kinds of seasonal banana, the summer-banana shows higher water content which will promot efruit starch hydrolysis in harvesting period of high temperature. Therefore, storage life might be increased by harvesting in lower maturity of summer-banana. B. The water content relates to different cultivated condition of autumn-banana: (1) There are no differences of water content of plant and fruit between water culture and land culture banana grown in course sand soil condition. (2) There are no differences of water content among different soil condition and different cultivation practices. They have same storage life. C. Water content between varieties and seasons: In same season, there are also no significant differences of water content between pei-chiao and Dwarf Chinese cultivars. The seasonal change of water content of these two cultivars can be put in the order of spring, summer, winter and autumn banana. The former has higher water content than the latter. The difference of water content between spring and autumn banana is 7% in Pei-chiao, 5.98% in Dwarf Chinese cultivars. The difference of summer-spring banana and winter-autumn banana is 4.90% in Pei-chiao, 2.66% in Dwarf Chinese. The important reasons of seasonal change might be explained by temperature and wind.