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.

著者

万木 豊 永田 洋 Yurugi Yutaka Nagata Hiroshi

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.p199-203, 1981-12

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この暖帯地方に分布する常緑広葉樹 4 種の長日条件と短日条件下での生長パターンをしらべ, その天然分布との関連を考察した。ヤマモモ・クスノキ, アラカンは長日条件, 短日条件下ともで周期的生長を示した。そこで, これら 3 樹種は亜熱帯地方では休眠に入ることなく, 分布可能なのであろう。タブノキは長日条件下で周期的生長を示すが, 短日条件下では 1 回のフラッシュをみたのみであった。このタブノキが亜熱帯地方に分布しているのは, 短日条件下でも周期的生長を示す生態型があるためであろう。Growth patterns of four evergreen broad-leaf trees distributed in this warm temperate zone on long-days and short-days were studied, and the relationship between growth patterns and distribution was discussed. Myrica rubra SIEB. Et ZUCC., Cinnamoum camphora SIEB., and Quercus glauca THUNB. showed periodic growth on long-days and even on short-days. So they can be distributed in the subtropical zone without being induced to bud dormancy. These three species seem to be induced to bud dormancy wit lowering temperatures in autumn, and to be released from bud dormancy with winter chilling in this region. Machilus thunbergii SIEB, et ZUCC. showed periodic growth on long-days, but showed only one flush and then no growth on short-days. It may be considered, therefore, that Machilus thunbergii can be distributed in the subtropical zone, having an ecotype showing periodic growth on short-days.