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有的植物的茎或叶会变成卷须缠绕在别的物体上。一种叫环药瓜的卷须特别敏感,只要一接触物体就会发生盘卷,用肉眼就可看到它在一分钟内卷曲在其他支持物上。葡萄的卷须无论哪一部分碰到支架就立即卷曲;但黄瓜的卷须只有在内侧或外侧的某一面上才有感受性,另一面则没有,即使碰到支柱也不会发生卷曲,仿佛什么也没有遇上。那末卷须为什么能发生卷曲呢?有人在棱角瓜卷须的上、下两面按一定间隔画上黑线,他们观察到卷须在未受刺激时,上、下两面都按相同比例生长,每20分钟大约增长2倍。但在受到刺激后,上方那一面在5分钟内竟增长了10倍,然而下侧则因为上侧的旺盛生长而受到压迫,不仅没有生长,反而收缩起来。这样
Some plant stems or leaves will become tendrils wrapped around other objects. A tendril called a ring melon is particularly sensitive, as long as it contacts the object coil occurs, with the naked eye can see it curled on other supports within a minute. The tendrils of the grapes curl immediately no matter where they hit the bracket; however, the tendrils of cucumbers are only sensible on one side of the medial or lateral side, and not on the other side, and do not curl even when they hit the pillars, as if nothing had happened on. Then why the tendrils tend to curl it? Some people in the angular melon tendrils on the upper and lower sides drawn at regular intervals on the black line, they observed that when the tendrils are not stimulated, the upper and lower sides grow in the same proportion, every about 20 minutes Increase by 2 times. However, after being stimulated, the upper side actually increased by 10 times in 5 minutes. However, the lower side was oppressed by the vigorous growth of the upper side, and not only did not grow, but contracted. such