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Please use this identifier to cite or link to this item: http://hdl.handle.net/10466/3117

Title: Papaw (Asimina triloba Dunal)の花芽分化に関する研究(園藝學)
Authors: 平井, 重三
Author's alias: HIRAI, Juzo
Issue Date: 25-Feb-1954
Publisher: Naniwa University
Citation: Bulletin of the Naniwa University. Ser. B, Agriculture and natural sciences. Zoology and botany. 1954, 3, p.141-147
Abstract: 1. Papawの花芽分化開始期,花器形態完成までの発達,分化期及新梢伸長停止期に於ける枝梢の長さ及び葉面積を調査し次の結果を得た.2. Papawは5月上~中旬に花芽分化を開始し,6月下旬には花器形態を完成する.3.花芽分化開始期に於ける新梢の長さは1~2cm,葉数は2~3枚,葉面積は36.8cm^2であった.然るに新梢の伸長停止期に於ける長さ及び面積は7.5~22cm,及び235.2~1207.7cm^2であった.4.以上の調査によりPapawの花芽分化は夏の高温に関係なく,又新梢上の葉によって生産されるその年の同化生産物との関係は他の一般落葉果樹と著しく趣きを異にするものと考えられる.
In the previous publication as to the fruiting habits of the papaw, the auther reported as follows: (1) In the papaw, flower buds are formed in the axillary position on the shoots of one year, and never formed terminally. And they contain flower part only. (2) On the vigorous shoots, flower buds are produced in the middle nodes of the shoots. But on the weak ones, flower buds are borne at each node next to the terminal leaf bud excepting lower nodes. (Fig.1) The present study reports the differentiation of flower buds of the papaw. In this investigation, the first noticeable differentiation of flower buds occurred about the middle of May. Sepal primordia appeared May 15; petals, May 25; stamens, June 14; pistils, June 19; and the various floral organs within the bud were morphologically completed by June 24. (Fig. 3) When differentiation of flower buds started, the young shoots bearing flower buds were only 1-2cm in length, and had 2-3 completely unfolded leaves. The total area of the leaves measured 36.8 square cm. (Fig. 5) But when the shoots completely matured, they had a length of 7.2-22cm and the leaves had an area of 235-1207.7 square cm. The time of differentiation, no doubt, varies somewhat; with the variety, locality, climatic codition, position on the plant, management, and other factors. By the results of various investigators, the differentiation of flower buds of deciduous fruit trees in this country generally start between the middle of June and the middle of August. In such a case the young shoots generally reach their maximum length, and the total area of leaves measures maximum. In the papaw, the area of leaves when differentiation began, measured only 1/6-1/32 of the area of leaves on the matured shoots. In most cases, just when rapid growth ceases, and carbohydrates accumulate or shortly after, flower buds begin to differentiate. In the case of the papaw, the differentiation starts shortly after the beginning of carbon assimilation by young leaves. (Fig. 4) Thus the flowerbud formation of the papaw is not so dependent for its Carbohydrate upon its own leaves as that of other fruit trees. The other distinguished difference between the papaw and other fruit trees is the rapidity of the development of the flower buds. In this country, the peach takes about 116 days from the beginning of flower-bud differentiation to the morphological completion of floral organs within the bud; Japanese pear, 153 days; Japanese persimmon 264 days. But in the papaw, it takes only about 45 days.
URI: http://hdl.handle.net/10466/3117
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