首页
登录
职称英语
Insects which eat grain and other stored food can be partially controlled b
Insects which eat grain and other stored food can be partially controlled b
游客
2024-10-06
0
管理
问题
Insects which eat grain and other stored food can be partially controlled by cooling the grain. But the damage insects cause can be further limited by making them even more susceptible to cold, says a Canadian researcher.
Insect pests die if they freeze, but many have the ability to become "supercool", remaining alive even when the temperature drops to - 10℃. However, Paul Fields of the Agriculture Canada Research Station in Winnipeg has discovered that the ability of these insects to supercool can be seriously affected by "ice-nucleating-active bacteria". When the bacteria are present, the insects freeze and die at a higher temperature than normal.
Ice-nucleating-active bacteria are found naturally on most plant leaves. They are also grown commercially for use in cloud seeding and in making artificial snow.
Fields added these bacteria to wheat which was stored at a temperature of - 10℃ and contained the rusty grain beetle. He found that when the bacteria accounted for only 10 parts per million of the grain, the beetles’ supercooling point rose from - 11.3℃ to - 7.1℃, so more died. At concentrations of 100 ppm or 1000 ppm, the bacteria increased the supercooling point to as high as -6.3℃, which resulted in more than 75 percent of the beetles dying.
Fields also applied the bacteria to two other species of grain beetle, Sitophilus granarius and Oryzaephilus surinamensis, keeping them at - 10℃. He found that more of these beetles also died. First, though, he gradually acclimatized some of the insects to cold, to simulate the increase in tolerance to cold which they normally develop as winter approaches. Fields found that the insects that had been acclimatized were less affected by cold than the beetles that had not been acclimatized, but that more of them still died at - 10℃.
Fields says that the technique of using ice-nucleating-active bacteria leaves no noxious chemical residues and poses little risk to the people who apply the treatment. It is also effective against insects which have become resistant to pesticides. [br] Which of the following statements about ice-nucleating-active bacteria is true?
选项
A、They may cool the grain to - 10℃.
B、They can weaken the beetles’ resistance to coldness.
C、They can be grown on most plant leaves.
D、They are used only in biological researches.
答案
B
解析
根据文章前三段可以判断此题应选B。
转载请注明原文地址:https://tihaiku.com/zcyy/3788952.html
相关试题推荐
Somepeople______gardeninsectsbysprayingpoisonontheplants.A、eraseB、ext
Ifnotstoredinthefridge,foodis______todeteriorateinsummer.A、feasibleB
Insectswhicheatgrainandotherstoredfoodcanbepartiallycontrolledb
Insectswhicheatgrainandotherstoredfoodcanbepartiallycontrolledb
Insectswhicheatgrainandotherstoredfoodcanbepartiallycontrolledb
Insectswhicheatgrainandotherstoredfoodcanbepartiallycontrolledb
Allthefinishedproductsarestoredina______ofthedeliveryportandshippi
Someinsectshavealife______ofnomorethanafewhours.A、potentialB、spanC
InarecentbookentitledThePsychicLifeofInsects,ProfessorBouviersay
Wemust______thattheexperimentiscontrolledasrigidlyaspossible.A、secure
随机试题
Theroomwants(clean)______beforetheSpringFestival.cleaning本题考查固定搭配。wantdo
[originaltext]W:TodaywehaveDanielLevitonwithustosharehisopinion
Theaudiencemusthavemissedtheirmusicalperformance,orthey______(会给予高度评价的
对于220KV及以下系统,通常设备的绝缘结构设计允许承受可能出现的3~4倍的操作
二层平面⑤-⑥轴与轴间(不包括楼梯平台处)的次梁数量(多跨连续梁计为一根)
一贯煎的功用是A.滋补肝肾 B.滋阴疏肝 C.滋养肺胃 D.滋阴降火 E
氧化锌避雷器发热的热像特征。正常为整体轻微发热,较热点一般在靠近上部且不均匀,多
“云母屏风竹影深,长河渐落晓星辰。”描写的是一天之中的哪一时段:A.黎明 B
表示传统师德非常重视严于律己、身体力行、为人表率的模范作用的先哲名言是( )。
在证券投资基金的当事人和关系人中,商业银行可以申请担任()A:基金监管人B:基
最新回复
(
0
)