상수지조(桑樹枝條)의 벌채정도(伐採程度)와 신초(新梢)의 발육(發育)과의 관계(關係)

春期發芽前에 枝條를 各各 先端伐採, 條長의 1/3, 1/2, 2/3伐採하여 發芽 生長하는 新芽의 發育狀況을 調査하였다. (1) 枝條를 伐採하면 不發芽比率이 大巾的으로 減少하여 無處理區의 半以下로 되는 것인데 1/3伐採區가 가장 그 比率이 적어진다. 그리고 또 枝條를 伐採하면 不發芽는 枝條의 下半部에 集中한다. (2) 枝條를 伐採하여도 發芽를 促進시키는 일은 없고 도리어 若干 늦어지는 傾向이 있는 것 같지마는 發芽後의 開葉速度는 매우 빨라져서 脫荀에서 부터 第5開葉期까지의 所要日數는 無處理區의 16일에 比하여 伐採各區는 7~9日이며 그 중 가장 빠른 것은 2/3伐採區의 7日이다. (3) 枝條를 伐採하면 新芽의 發育을 促進시켜서 5月5日부터 6月10日까지 45日間의 生長量이 無處理區의 34cm에 比하여 伐採各區는 그 1.6~2.5倍나 生長하여 가장 生長量이 큰 것이 2/3伐採區의 83cm이다. 그리고 伐採各區는 生長速度도 無處理區에 比하여 빠르다. (4) 葉數의 增加比率은 無處理區에 比하여 伐採各區가 若干 많기는 하지만 그 差는 그리 크지 않다. (5) 新芽의 總生長量은 無處理區에 比하여 伐採各區가 顯著하게 많으며 2/3伐採區는 生長繼蹟芽數가 伐採各區中에서 가장 적지만은 1芽의 平均芽長이 가장 길다. (6) 新梢揷木의 揷藪를 되도록 빨리 採取하기 위해서는 條長의 2/3程度를 伐採하는 것이 적당할 것 같다. The aim of this work was to investigate how the mulberry shoots grew well when the mulberry branches were cut down, in hight, 1/3, and 2/3 of them, respectively, just before the Spring budding. The results obtained are as follows: 1. The rate of un-sprouted buds decreased sharply down as much as half of the control if the mulberry branches were cut off. The treatment, 1/3, was best one of various cut down sizes and the un-sprouted buds concentrated on the lower parts of the branches. 2. Even though the branches were cut down, at first it seemed flat to accelerate the sprouting of buds, but rather to have a tendency to become late. The speed of leaf growth, however, became faster after the sprouting. It took 7~9 days from the beginning of buddings to the 5th full grown leaf, and 7 days for the shortest one in the treatment, 2/3, when compared with 16 days of the control. 3. If the branches were cut down, the growth of the new sprouts was accelerated. For 45 days (on 5th of May to on 10th of June), therefore, the shoots had grown up to 1.6~2.5 times of the control, 34cm long. The shoots of which the branches were cut down at 2/3 of them were longest (83cm). Furthermore, the speed of shoot growth of cut-down branches was faster than that of the control. 4. In the increased rate of the number of the mulberry leaves, there was not significant difference between the control and the treatments. 5. The total amount of shoot growth showed considerably much more in the treatments than in the control. The successing growing shoots of treatment, 2/3 were little in a number but longest per one shoot in mean shoot length. 6. It seems to be much available that we may cut down branches at 2/3 of them in order to get the scions for the cutting as soon as possible.