时间:2019-01-20 作者:英语课 分类:Scientific American(七)月


英语课

   Lawn enthusiasts 1 love a lush, green carpet of grass, which is why they hate crabgrass. And now they may have one more reason to despise the weed. Because crabgrass isn't just faster-growing than the rest of lawn. It may actually be poisoning the lawn, by pumping herbicide into the soil. That's according to a study in the Journal of Agricultural and Food Chemistry. Researchers grouped crabgrass hydroponically, so they could easily capture any chemicals released by the plant's roots. Then they dripped that hydroponic solution into pots of wheat, corn and soy bean seedlings 2. Two weeks later, they dried and weighted the seedlings. And sure enough, the crabgrass solution had significantly stunted 3 the seedlings' growth, compared to control plants. And since corn is in the same family as lawn grasses, the crabgrass toxic 4 effect may also spill bad news for your beautiful Kentucky bluegrass. The researchers still aren't exactly sure how crabgrass' chemical weapons work. But the weed can wipe out beneficial bacteria and fungi 5 in the soil, too. So it's possible crabgrass poisons its neighbors directly, by releasing toxins 6 and indirectly 7, by creating inhospitable soil. Either way, it's bound to make lawn-owners crabby.



n.热心人,热衷者( enthusiast的名词复数 )
  • A group of enthusiasts have undertaken the reconstruction of a steam locomotive. 一群火车迷已担负起重造蒸汽机车的任务。 来自《简明英汉词典》
  • Now a group of enthusiasts are going to have the plane restored. 一群热心人计划修复这架飞机。 来自新概念英语第二册
n.刚出芽的幼苗( seedling的名词复数 )
  • 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》
adj.矮小的;发育迟缓的
  • the stunted lives of children deprived of education 未受教育的孩子所过的局限生活
  • But the landed oligarchy had stunted the country's democratic development for generations. 但是好几代以来土地寡头的统治阻碍了这个国家民主的发展。
adj.有毒的,因中毒引起的
  • The factory had accidentally released a quantity of toxic waste into the sea.这家工厂意外泄漏大量有毒废物到海中。
  • There is a risk that toxic chemicals might be blasted into the atmosphere.爆炸后有毒化学物质可能会进入大气层。
n.真菌,霉菌
  • Students practice to apply the study of genetics to multicellular plants and fungi.学生们练习把基因学应用到多细胞植物和真菌中。
  • The lawn was covered with fungi.草地上到处都是蘑菇。
n.毒素( toxin的名词复数 )
  • The seas have been used as a receptacle for a range of industrial toxins. 海洋成了各种有毒工业废料的大容器。
  • Most toxins are naturally excreted from the body. 大部分毒素被自然排出体外。 来自《简明英汉词典》
adv.间接地,不直接了当地
  • I heard the news indirectly.这消息我是间接听来的。
  • They were approached indirectly through an intermediary.通过一位中间人,他们进行了间接接触。
标签: 美国科学60秒
学英语单词
a bird
a very matter-of-fact person
abrading stone
afor
agreed plan
Altares
amenorrheic
antipsychiatric
arish
arrans
audifier inquiry
azimuth at present position
bachatero
Barre's sign
batch-still system
beginning of information marker
bevelled door
boiler circulation
Buhūt
calcium cylinder
calmness
ceramic liner
chamber gases
chirne
combinatorial optimization problem
companisation
continuous concreting
corrugated wood plug
cyathulae radix
desiring
dictyla evidens
digital to AC converter
Diophantine predicate
dogmatic theology
doubly connected surface
Dunkardian
easy-comes
fritted hearth bottom
genus arundoes
genus Retrophyllum
go-and-return resistance
goatgrasses
hapeville
hardware company
heavy on hand
heavy section mill
high mobility multipurpose wheeled vehicle
hyperboloid of revolution
intracluster correlation
ion limit
Kelč
kogaluk r.
Legislative Day
lepidotrigla hime
Lewis and Clark Expedition
magnetic transport effect
manc-y
manufacturing management
mineless
multangulum
musical boxes
n-ethyl phenylamine
NAWCH
nonexperimentally
Norren
order primatess
passive fibre optics element
Pavetta hongkongensis
percentage of theoretical slope
Phendextro
pleurostoma candollei
plussage
premoral
principal officials
progressive onlap
psychopathic personality
pulsed voltage
rare gas mixture
recursion analysis
related subjects
scns
shift to the left
speak forty to the dozen
spindle counterweight
standard edition
strathpeffers
terrestrial satellite
the right wing
to put it mildly
top fermenation
trample on
transitive trust
trochoidal mass analyzer
tudorbethans
ultradense plasma
unsely
utia
uvitonic acid
vegetable theory
Vyazniki
whatman filter paper
zig-zag dislocation