- 作者: 朱慶國
- 作者服務機構: 臺灣省農業試驗所嘉義農業試驗所
- 中文摘要: This studies are to observe the influence of seasonal variation on the growthof banana leaves, to find out the corelations among leaf number, leaf size, bunchyield and fruit quality and the effect of some important factors, such as fertilizers,plant density, occurence of leaf-spot disease, etc, on the growth and longevity ofbanana leaves. Results obtained are summarized as follows: 1. Influence of seasonal variation on the growth of banana leaves: There are two distinct periods in a year: (1) From April to September, whenweather is warm and rainy, the growth of banana leaves is very vigorous, and (2)From October to March, it is a cold-dry season, the banana leaves grow very slowly.In the warm and rainy season, the number of days from leaf unfurling to fullexpansion is only 7.9-9.2 days, while in the cold-dry season, from December toJanuary, it is 20.74-24.10 days, so a significant difference is found at various season. The development of number of banana leaves is also very closely related tothe climatic condition. In the warm-rainy season, more than 3.5-4 leaves can growever month (May to August), but during the cold-dry season only 0.56r-1.01 leavesunfurled monthly without irrigation, and 1.61-1.92 leaves under irrigation condition. The longevity of banana leaves shows a seasonal change. Those leaves grownin dry and cool season (November to January) survive longer than those in warm-rainy summer season, averagely the former ones last 180-200 days and the latter,94.2-96.8 days. Leaf-spot disease is another factor that affects the leaf longevity. The development of size of banana leaves in the early part of January has theslowest rate, with 0.98 cm. in the day-time, and 0.28 cm. in the night time. As thetemperature becomes higher in middle June, the leaf development has a fastestgrowth rate with 4.57 cm. in the day time and 12.21 cm. in the night time when theaverage temperature is 29.58℃. The growth rate of banana leaves in the nighttime (from 5:00 P.M. to 8:00 A.M.) is about 1-3 times higher than that in the day-time (from 8:00 A.M. to 5:00 P.M.). Except in the early part of January, thegrowth rate in the day-time is higher than night, because the temperature is below10℃. in the night time, and the leaves almost cease to develop. Relation of temperature to the development of banana leaves; banana leaveswill fully cease to develop when the daily average temperature is below 10℃.When the temperature increases to 17-21℃, the development of banana leaves isfaster, but still less than 5 cm in each day. The favorable temperature for bananaleaf development is above 23℃, expecially in 29-30℃, it grows more than 16 cmeach day. When the temperature decrease to 4-5℃ in the night time, the bananaleaves are damaged by freezing. Rain-fall also affects the leaf development of banana, the growth rate increaseswith 1-3 cm a day to about 4-5 days after rain-fall during the hot season. But thedifference is not as significant as temperature. 2. The relation of the leaf number and acreage to the bunch yield: The total number of leaves formed by a banana plant is about 36-46 leaveswith less than 15 cm. of width) the average is 41.74 leaves. Banana plant has more green leaves both at shooting stage and harvesting time,it produces heavier bunch and higher quality of fruit. The yield of banana's fruit in proportion to the size of banana leaves both thelength and width. 3. Influence of leaf spot disease on the longevity of banana leaves: The leaf development from June to August has the longevity of leaf with only110-115 days, due to serious infection of leaf spot disease in rainy season. Thoseleaves which developed from November to January last 180 days, because it isdifficult to infect in the cold-dry season. It is evident that the leaf-spot disease isthe most important factor which affect the decrease of longevity of banana leaves. 4. Suitable application of fertilizers (N.P.K.=1:1:3) helps increase the numberof leaves about 1-2 leaves, and the size of leaf. Application of medium and heavyquantity of potassium fertilizers which caused the longevity of leaves to be about3.60-5.15 days longer than the application of light quantity. The quantity of nitro-genous fertilizer has not influenced on the longevity of leaf. 5. Suitable planting space also helps increase the number and longevity ofabout 11 days longer than dense planting.
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