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中間温帯に位置する三重大学演習林の二次林において，シカの剥皮における嗜好性3樹種，不嗜好性3樹種，および剥皮害を受けた全樹種全個体を対象にそれらの分布様式と分布相関の変化を13年間調べた。嗜好性3樹種では個体数減少とともに分布が散在化したが，不嗜好性3樹種では個体数の変動が少なく集中分布が維持された。不嗜好性3樹種はシカ剥皮害集団と排他的分布を示し，不嗜好性3樹種の剥皮害に対する忌避効果が考えられる。不嗜好性3樹種と嗜好性3樹種との排他的分布や，嗜好性3樹種の剥皮害率の高さから，不嗜好性3樹種の分布が嗜好性3樹種にとって剥皮害からの避難地となる可能性は低いと推察される。

Pinus luchuensis MAYR can be found throughout in Okinawa Prefecture (Subtropical Zone) on the photoperiods ranging from 11 to 15 hr. The terminal buds of this pine are not considered to be induced into the winter dormant state requiring winter chilling for its release. It is considered also that the shoot growth (internode elongation) of this pine is active on the photoperiods of 14 to l5 hr, and that leaf-primor-dia differentiation (activity of apical meristem) is active on the photoperiods of 11 to 12 hr. Therefore, on the intermediate photoperiods of 12 to 14 hr, the balance between growth and differentiation is kept on a 50-50 basis, and the balanced continuous shoot growth without branching (fox-tailing) is induced. In fact, a higher incidence of foxtailing was observed on the photoperiods of 12 and 13 hr without any special temperature control (Fig. 1-5 and Table 1). Under the temperature controlled conditions, however, not only photoperiod but also temperature is shown to have a great influence on inducing foxtailing. The highest incidence (80%) of foxtailing for over 500 days was observed on 12-hr phtoperiods at a constant temperature of 25℃. While no foxtailing was observed on 12-hr photoperiods of a 25℃ day temperature (8 hr) with a 15℃ night temperature (16 hr) as well as on 16 hr phtoperiods at a constant temperature of 25℃ (Fig. 6-8 and Table 2). Therefore,a low incidence of foxtailing at high elevations and latitudes seems to result from the longer photoperiods (high latitudes) and the greater difference between day and night temperatures(high elevations and latitudes). True foxtailing is the balanced continuous shoot growth without branching taking place in the area with small annual and diurnal fluctuations in temperature in the Tropical Zone (photoperiods of 12-14hr). In this case, both leaf-primordia differentiation and internode elongation do occur together withoutcorrelated inhibition throughout the year.

The terminal buds of Machilus seedings from the seeds collected in the Subtropical Zone(Iriomote,Okinawa,Amami) could not survive the winter, but the seedlings from the Temperate Zone(Kagoshima,Kochi,Mie,Chiba,Iwate,Aomori) grew up well without frost damage in Mie(Table 1). The terminal buds of Machilus seedlings grown in the Subtropical Zone were not induced into thedormacy requiring chilling for its release and had a relatively wide range of temperatures suitable forbud break(Table 4 and 5). So the terminal buds often sprout in the winter in Mie and then are killedby frost. On the other hand, the terminal buds of Macilus seedlings collected from the Temperate Zonecould be induced into the dormancy requring chilling for its release(Table 4 and 5)and sprouted inspring without frost damage in Mie. This dormancy,however,could not be induced with short-days at the temperatures ranging from 18 to 28℃(Fig.5-8). The relationship between photoperiod and temperature seems to play an important role in inducing dormancy. And photoperiod seems to have a great effect on the growth patterns,that is, the relationship between leaf initiation and internode growth(Fig.9).

The effects of temperature on the terminal bud formation of Populus x euramericana cv. I-214 inresponse to the short-day condition were investigated. Terminal bud formation was inhibited by relativelylow and high temperatures during the dark periods. The optimal nycto-temperature was about 25℃(Table 1-5).Then the critical photoperiod for terminal bud formation is the longest at 25℃(Fig.1). The effective temperature during the 6-hr supplemental light period, of the 14-hr photoperiod, inducingcontinuous shoot growth was higher than 25℃,but the lower ones were effective for promotingterminal bud formation(Table 6). The critical length of photoperiod for terminal bud formation is considered to be varied by thetemperatures of the light period and dark period and by their combination(Table 7.)

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.

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.

サクラ (アサヒヤマ) の花芽は休眠の最も深い時期には 25°C 連続光下でも開花しない。津地方では, このサクラは 12 月下旬には, 20°, 25°C 連続光下で開花するようになり, 1 月中旬には 15 °C連続光下で, 2 月下旬には 10°C 連続光下で開花するようになる。また, 低温処理 (5°C) を長くするほど, 低い温度条件下で開花できるようになる。開花可能温度は 2 月下旬には 10°～15°C にまで低下する。そして, 花芽の温度は晴れた日には気温より 2°〜3°C は高いので, 2 月下旬には花芽は開花に向ってうごきだしてくる。一旦, 花芽が開花に向ってうごきだすと, 日平均気温の積算が 500 度日位になると満開になる。これらの結果から, 冬の暖かい地方では冬の寒い地方より高い気温でソメイヨシノが開花していると考えられる。事実, 日本各地でのソメイヨシノの開花日の平均気温には相当の差があり, 降霜期間の長さと開花日の平均気温との間に優位な相関がみられる。しかし, ウメでは, この相関関係は真冬日がない地方と真冬日が毎年はみられない地方においてのみ有意である。ウメの場合, 年平均真冬日が 4 日以上ある地方では, 開花はいちじるしくおくれる。すなわち, 気温が高くなってから咲く。まだ気温の低い早春に開花するものは, 真冬日によって開花がおくれるが, 気温が高くなる晩春に開花するものは, 真冬日によって開花はおくれない。凍結 (真冬日) は, ポプラでみられたように, 休眠解除において凍結をともなわない低温とはちがった効果を持っているようである。, In a deep dormant condition, flower buds of Prunus lannesiana WILSON f. asahiyama HORT. Are not induces to open even under continuous light (CL) at 25°C, In this region, flowering can be induced under CL at 20° or 25°C in late December, at 15°C in mid-January, and at 10°C in late February. The longer the chilling (5°C) period, flowering can be induced at the lower temperature. The flowering temperature dropped between 10° and 15°C in mid-February. Temperature in flower-bud (2°〜3°C higher than the air temperature in the sunshine) often rose over 15°C even in late February and flower buds began to develop to flowering. Accumulation of daily mean temperature when the cherry trees flowered 80% averaged 500 degree-days after the beginning of development to flowering. From the results, it is considered that flowering of Prunus yedoensis MATSUM. (flowering date is observed on a nation-wide scale by the Japan Meteorological Agency) can be induced at the higher temperatures in the warm winter regions with short frost period than in the cold winter regions with long frost period. In fact, the mean temperatures (normal value) of the average first flowering date varies considerably with regions in Japan. For example, in Miyazaki city the average frost period (from the average first frost date to the average last frost date) is 124 days and the mean temperature of average first flowering date is 12.5°C. While in Sendai city the average frost period is 175 days and the mean temperature of average first flowering date is 9.1°C. The mean temperatures (normal value) of average first flowering date are significantly related inversely to the average frost periods in Prunus yedoensis. In Prunus mume SIEB. et ZUCC., however, the mean temperatures of average first flowering date are significantly related inversely to the average frost periods only in the regions where ice days (maximum temperature < 0°C) do not exist at all or every year. Flowering of Prunus mume is markedly delayed in the regions with 4 or more ice days (average per year). Flowering in early spring (under the low temperatures) is delayed by ice days, but ice days do not delay flowering in late spring (under the high temperatures).