SSS 2011-08-02
时间：2019-01-08 作者：英语课 分类：Scientific American(八)月
英语课
Plants are sitting ducks for every hungry herbivore that wanders past. But for some greens, a little grazing is the best thing that can happen. They grow back faster and fuller and make more seeds than they would have if left alone. Now scientists know how they do it—by stockpiling their DNA 1. The findings appear in the journal Ecology.
Most animals have two full sets of chromosomes 2: one inherited from mom and one from dad. But plants don’t play by the same rules. Banana plants have three full sets; strawberries eight. And plants that get noshed on may take a similar tack 3.
Scientists took two strings 4 of plants: one that comes back strong after grazing, another that wilts 5. And they found that the plants that bounce back after clipping boost their DNA content—some of their cells go from having 10 chromosomes to having 320.
The added DNA may allow the plants to rapidly make the proteins they need to grow and to produce seeds. And the size of the nucleus 6 needed to contain all those chromosomes may make those cells bigger and bigger cells means a bigger plant. So chewed-on plants can fight back, and they are not afraid to go nuclear.
Thanks for the minute. For Scientific American’s 60-Second Science, I’m Karen Hopkin.
(缩)deoxyribonucleic acid 脱氧核糖核酸
- DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
- Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。
n.染色体( chromosome的名词复数 )
- Chromosomes also determine the sex of animals. 染色体也决定动物的性别。 来自《简明英汉词典》
- Each of four chromosomes divide longitudinally. 四种染色体的每一种都沿着纵向分裂。 来自《现代汉英综合大词典》
n.大头钉；假缝，粗缝
- He is hammering a tack into the wall to hang a picture.他正往墙上钉一枚平头钉用来挂画。
- We are going to tack the map on the wall.我们打算把这张地图钉在墙上。
n.弦
- He sat on the bed,idly plucking the strings of his guitar.他坐在床上，随意地拨着吉他的弦。
- She swept her fingers over the strings of the harp.她用手指划过竖琴的琴弦。
（使）凋谢，枯萎( wilt的第三人称单数 )
- The bacteria may gain entry and develop internally as in wilts and stunts. 当植株产生萎蔫或矮化症时细菌可进入体内繁殖。
- The bacteris may gain entry and develop internally as in wilts and stunts. 当植株产生萎蔫或矮化症时细菌进入体内繁殖。