英语听力文摘 English Digest 590、植物的夜生活！

 　　The Nightlife Of Plants

 

　　Most plants grow buds, flower, or lie dormant¹ at specific times of year.

 

　　What Triggers These Seasonal² Changes?

 

　　Temperature and rainfall often play a role, but the most important factor to many plants is the length of the day. At least, that’s what biologists thought until the 1940s, when the whole concept of day length sensitivity in plants was turned upside down.

 

　　Experiments showed that plants that seem to flower in response to day length actually respond to night length. In other words, what prompts irises³ to bloom in summer in North America isn’t longer sunny days, but shorter nights.

 

　　Here’s how biologists figured out how important nightlife can be to plants. They started with the cockle burr plant, which flowers when days are short. Midway through the day, the biologists exposed the plants to a brief period of complete darkness. What effect did this have on flowering? Absolutely none.

 

　　Next, for several nights, in the middle of the night, they exposed the plants to a brief period of light. To the biologists’ surprise, this brief interruption of the darkness inhibited⁴ flowering. Clearly it was the long period of darkness and not the short period of light that caused flowering.

 

　　Although plants are sensitive to the nighttime part of the light-and-dark cycle, biologists and gardeners often still refer to plants as day length sensitive.

 

　　For example, poinsettias are called “short-day” plants because they flower in winter. A stickler⁵ for accuracy might call poinsettias “long-night” plants, because what prompts their flowering isn’t the short days of winter, but the long nights.

 

 

 

 

 

　　植物的夜生活

 

　　大多数植物在每年的特定时间发芽，开花，或者冬眠。

 

　　是什么引起植物这些季节性的变化呢？

 

　　温度和降雨通常会有所影响，但是对许多植物来说，最重要的因素是昼长。至少在20世纪40年代之前，生物学家们是这样认为的，之后植物对昼长敏感的理论被彻底推翻。

 

　　实验显示，那些看起来受日长影响而开花的植物实际上是受夜长影响。换句话说，促使北美地区的鸢尾花在夏季盛开的不是更长的白天，而是更短的夜晚。

 

　　下面让我们来揭秘生物学家是怎样确定夜生活对植物的重要性的。他们由苍耳开始研究，这种植物在昼长较短时开花。生物学家让植物在白天一个短暂的时期内陷入完全的黑暗。这对植物开花有什么影响吗？答案是：完全没有影响。

 

　　接下来，他们连续几晚让植物在半夜接受短时间的光照。令生物学家吃惊的是，这对黑暗的短暂中断抑制了植物开花。很明显是由于长时间的黑暗，而不是短时间的光照导致的开花。

 

　　尽管植物对日夜交替中的夜间部分敏感，但是生物学家和园丁们还是通常倾向于认为植物是对昼长敏感的。

 

　　举个例子，一品红因为在冬天开花被叫做“短日照”植物。一个坚持细节的人为了精确可能称一品红为“长夜”植物，因为促使它们开花的不是冬天的短暂白昼，而是冬天的漫漫长夜。

1 dormant   

adj.暂停活动的；休眠的；潜伏的

参考例句：

• Many animals are in a dormant state during winter.在冬天许多动物都处于睡眠状态。
• This dormant volcano suddenly fired up.这座休眠火山突然爆发了。

2 seasonal   

adj.季节的，季节性的

参考例句：

• The town relies on the seasonal tourist industry for jobs.这个城镇依靠季节性旅游业提供就业机会。
• The hors d'oeuvre is seasonal vegetables.餐前小吃是应时蔬菜。

3 irises   

n.虹( iris的名词复数 )；虹膜；虹彩；鸢尾（花）

参考例句：

• The cottage gardens blaze with irises, lilies and peonies. 村舍花园万紫千红，鸢尾、百合花和牡丹竞相争艳。 来自《简明英汉词典》
• The irises were of flecked grey. 虹膜呈斑驳的灰色。 来自《简明英汉词典》

4 inhibited   

a.拘谨的，拘束的

参考例句：

• Boys are often more inhibited than girls about discussing their problems. 男孩子往往不如女孩子敢于谈论自己的问题。
• Having been laughed at for his lameness,the boy became shy and inhibited. 那男孩因跛脚被人讥笑，变得羞怯而压抑。

5 stickler   

n.坚持细节之人

参考例句：

• She's a real stickler for etiquette,so you'd better ask her advice.她非常讲求礼节，所以你最好问她的意见。
• You will find Mrs. Carboy a stickler about trifles.您会发现卡博太太是个拘泥小节的人。