著者

永田 洋 万木 豊 Nagata Hiroshi Yurugi Yutaka

出版者

三重大学農学部

雑誌

三重大学農学部学術報告 (ISSN:04624408)

巻号頁・発行日

no.63, pp.p205-216, 1981-12

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オオシマザクラ系の一品種, アサヒヤマの花芽形成は 8 月下旬に始まる。しかし, 9 月中旬までの分化形成過程にある花芽を機械的処理により開花を強制すると, 花芽から葉芽にもどってしまう。9 月下旬になると, この様な現象はみられない。そして, この時期には, 一重桜としての形態は一応完成されている。10 月に入ると, がく片の完成にひきつづき, 花弁と雄ずいが形成増加し, 10 月下旬には八重桜としてのアサヒヤマの花芽が完成する。三重県鈴鹿市白子のフダンザクラは, 通常, 10 月から 4 月まで開花がみられる。しかし, 開花のピークは秋 (10 月か 11 月) と春 (3 月か 4月) にある。これは一種の"狂い咲き"現象であり, 落葉が大巾に送れた 1978 年は秋の開花ピークがみられなかった。そのため, 翌春の開花総数は最高であった。In Prunus lannesiana WILSON f. asahiyama HORT., flower initiation occurred in late August, but until mid-September, the flower buds forced to open by mechanical treatments seemed to be reversible to vegetative stage, in the process of flower differentiation. In late September, flower buds will not reverse to vegetative even if they are forced to open. This is the time when single flower formation is complete. In early October, sepal formation occurred. October is the season while petal and stamen increase, and double flower formation is ended by the end of October. Flower buds are full-dormant in late August, and they will not be induced to flower by unseasonal defoliation in antumn. The cherry trees named Fudanzakura flower usually from October to April with two peaks in October or November and in March or April. This is a kind of unseasonal flowering brought about by too early defoliation before full-dormancy induction of the flower buds. So, if defoliation is delayed, unseasonal flowering will not be observed. In fact, in 1978 defoliation was delayed (still earlier than other cherry trees defoliation), and one flowering peak in autumn was not observed and another flowering peak in spring was the highest.