【英语时差8,16】遮荫避综合症

Don: What's wrong with these plants, Ya?l? They've grown all long and spindly, and just  have a few small leaves!

Ya?l: Hmm. It could be SAS, Don.

D: SAS?

Y: Plants that grow tall and spindly trying to reach the sunlight are usually "suffering"   from Shade Avoidance Syndrome¹, or SAS. Now scientists have identified the  molecular process that controls the onset² of SAS. When a plant that requires bright  sunlight detects shade from another plant, it will switch into SAS mode and try to  quickly grow taller, up into sunlight again.

D: That's a clever strategy.

Y: Yep. To figure out how SAS worked, researchers at the Salk Institute in California   searched through a large collection of mutated plant seedlings³ for individual plants  that didn't turn on shade responses even when in their neighbor's shadow. From  these plants, the researchers were able to identify genes⁴ involved in the shade      response. They found that one of the genes produces an enzyme⁵ that speeds up  production of a plant growth hormone⁶ called Auxin when the plant is shaded.

D: Growth hormone, eh? So that's why the plants get taller and taller when light-   depived?

Y: Right. The plants have receptors in their cells that are sensitive to light. When these   photo-receptors detect the presence of neighboring plants, it triggers the Auxin-      producing pathway, which triggers the stem to start growing rapidly.

D: I suppose growing taller diverts the plant's resources away from reproductive efforts  like making flowers, fruits and seeds.

Y: That's one reason that understanding SAS has such exciting potential. Crop breeders  and farmers could eventually use these new discoveries to maximize the yield of   grains or fruits in their fields.   

1 syndrome   

n.综合病症；并存特性

参考例句：

• The Institute says that an unidentified virus is to blame for the syndrome. 该研究所表示,引起这种综合症的是一种尚未确认的病毒。
• Results indicated that 11 fetuses had Down syndrome. 结果表明有11个胎儿患有唐氏综合征。

2 onset   

n.进攻，袭击，开始，突然开始

参考例句：

• The drug must be taken from the onset of the infection.这种药必须在感染的最初期就开始服用。
• Our troops withstood the onset of the enemy.我们的部队抵挡住了敌人的进攻。

3 seedlings   

n.刚出芽的幼苗( seedling的名词复数 )

参考例句：

• Ninety-five per cent of the new seedlings have survived. 新栽的树苗95%都已成活。 来自《现代汉英综合大词典》
• In such wet weather we must prevent the seedlings from rotting. 这样的阴雨天要防止烂秧。 来自《现代汉英综合大词典》

4 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

5 enzyme   

n.酵素，酶

参考例句：

• Above a certain temperature,the enzyme molecule will become unfolded.超过一定温度，酶分子将会展开。
• An enzyme that dissolves the fibrin of blood clots.能溶解血凝块中的纤维的酶。

6 hormone   

n.荷尔蒙，激素，内分泌

参考例句：

• Hormone implants are used as growth boosters.激素植入物被用作生长辅助剂。
• This hormone interacts closely with other hormones in the body.这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。