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
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ALCF
anagenic
ancohumas
attame
Balingian
be hard to cultivate
Birtwistle
calciovolborthites
Celerina
ceruloplasma
columellate
communications sink
comprehensive road maintaining vehicle
concentrated fall
copy recipient
curtain walls
cut matrix
cyberservice
cystocarcinoma
diethylamino
differential pressure pick-up
eastern jackrabbits
el-islam
engineering company
Entomopoxvirinae
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final exchange line
fishing quay
fly ash
full section
good credit risk
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hand casta
heart lines
horse-corsing
huffaker
in perpetuity
independent particle model
industrial cities
insulation quality
intel 815 chip
international geographical union (igu)
laminated iron core
landing craft tank
lanx
lgs
Listera bambusetorum
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low pressure
lubras
Malta
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Mesembryanthemum
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Montenay
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ofdaw
onerous act
outer cylinder
outflow channels
paratrigeminal
penley
Peucedanum rubricaule
philosophical necessity
piloting district
pinatas
plastic corpuscle
polyhydroxyurethanes
preotic myotome
pulse code modulation system
reduced cubic equation
regeneration of striated muscle
relative size of the public sector in grossdomestic product
Rhizoctonia crocorum
rigid dynamics
ring oiling
sedimentary supply
semiformed
separation cocycle
similarity index
sir charles
slip out from someone's hand
sneezing reflex
solidified resin
spirtual
steel trowel finish
straighten ... out
symmetrical body
tellez
TGSE
the Pacification Guards
Thelxinoe
Tres Lagos
tricing pendant
understrappers
us k
vampish
vector bundle
vowel sound
wild bred