Birch Trees Droop at Night with No Rays in Sight

时间:2016-09-23 16:34:16  / 编辑:Abby
   It’s easy to see that some plants change from day to night—flowers open and close, and even turn to face the sun. In 1880 Darwin noted that the leaves and seedlings of various plants appeared to engage in nighttime changes that he called sleep. But there’s now evidence that some entire trees may have their own version of sleep, which lets them recharge for the following day. That’s according to a study in the journal Frontiers in Plant Science. [Eetu Puttonen et al., Quantification of Overnight Movement of Birch (Betula pendula) Branches and Foliage with Short Interval Terrestrial Laser Scanning]

  Researchers used lasers to scan birch trees in both Finland and Austria. They found that the branches drooped by as much as four inches at night compared with daytime.

  And exposure to the elements was not responsible—the trees were surveyed from sunset to sunrise over enough time to rule out the changes being caused by wind or other external environmental factors.The researchers have a couple of ideas about what’s causing the branches to slouch.

  One is that the fluid pressure inside the tree decreases—something like dehydration.The other proposal is that the trees are actually engaged in a botanical version of sleep. During the daylight hours the leaves perk upwards to get more sun, but with no chance to catch rays at night, they relax. And even before the sun rose, some branches were found to be returning to their daytime position—as the researchers say, perhaps governed by their internal circadian clock in preparation for a new day of light gathering.

  But unlike us, there’s no evidence that trees sleep in on the weekend.

  —Erika Beras

  以上是一诺留学小编给大家介绍的内容,希望可以帮助到同学们,同学们如果还有任何关于英语学习的问题,可以拨打【一诺留学】的免费咨询热线400-003-6508或010-62680991进行咨询,或者点击页面的【在线咨询】与顾问老师直接对话。

  更多热点资讯欢迎关注:

  新浪官方微博:@北京诚品一诺教育咨询

  微信订阅号:留学圈 (微信帐号:yinuoliuxue )

免费发送到我的邮箱:
推荐专家
  • 姓名:肖秀

专业资历

国内知名院校英语专业硕士,对留学行业感情深厚,见解独特。具备很强的逻辑思维能力,注重细节,践行“预则立,不预则废”的原则,保障学生申请无忧。凭借扎实的专业水平,贴心的服务与较为丰富的成功申请经验赢得了良好的口碑。
 

成功案例

1、CAO同学 东北财经大学 经济学专业

GPA:3.0 IBT:104 GRE:319

乔治城大学经济学专业录取

2、DING同学 北京第二外国语大学 英语专业

GPA:3.6 IELTS:7

伦敦政治经济学院媒体,传播与发展专业录取

3、WU同学 北京工商大学 工商管理

GPA:3.3 IELTS:6.5

香港中文大学广告学专业录取

4、CHEN同学 中央财经大学 会计专业

GPA:3.5 IBT: 105 GMAT: 750

圣路易斯华盛顿大学会计专业录取

5、MA同学 对外经济贸易大学 金融专业

GPA:3.65 IELTS:7.5 GMAT:730

英属哥伦比亚大学金融专业录取

6、XUE同学 天津大学 化学专业

GPA:3.7 IBT: 104 GRE:323

康奈尔大学化学专业博士录取

向他提问

  •  
  •  
  •  
  •  
  •  
  •  
               

关注一诺留学

版权所有@2012-2016    一诺留学网    京ICP备12034294号-1

联系电话:400-003-6508  010-62680991     传真:010-82483329     邮箱:service.bj@yinuoedu.net