首页
登录
职称英语
About fifty years ago, plant physiologists set out to grow roots by themselv
About fifty years ago, plant physiologists set out to grow roots by themselv
游客
2025-02-01
9
管理
问题
About fifty years ago, plant physiologists set out to grow roots by
themselves
in solutions in laboratory flasks. The scientists found that the nutrition of isolated roots was quite simple. They required sugar and the usual minerals and vitamins. However, they did not require organic nitrogen compounds. These roots got along fine on mineral inorganic nitrogen. Roots are capable of making their own proteins and other organic compounds. These activities by roots require energy, of course. The process of respiration uses sugar to make the high energy compound ATP, which drives the biochemical reactions. Respiration also requires oxygen. Highly active roots require a good deal of oxygen.
The study of isolated roots has provided an understanding of the relationship between shoots and roots in
intact
plants. The leaves of the shoots provide the roots with sugar and vitamins, and the roots provide the shoots with water and minerals. In addition, roots can provide the shoots with organic nitrogen compounds. This
conies in handy
for the growth of buds in the early spring when leaves are not yet functioning. Once leaves begin photosynthesizing, they produce protein, but only mature leaves can "export" protein to the rest of the plant in the form of amino acids. [br] What is the main topic of the passage?
选项
A、The relationship between a plant’s roots and its shoots.
B、What can be learned by growing roots in isolation.
C、How plants can be grown without roots.
D、What elements are necessary for the growth of plants.
答案
A
解析
主旨题型。见本文主旨句,第二段第一句:The study of isolated roots has provided anunderstanding of the relationship between shoots and roots in intact plants.(第一段谈的是the study of isolated roots;第二段谈的是the relationshipbetween shoots and roots);因此选项A应为答案。
转载请注明原文地址:https://www.tihaiku.com/zcyy/3937787.html
相关试题推荐
Somepeopleprefertoworkforthemselvesorownabusiness.Othersprefertowo
Sincetheexecutiveteamsofbothfirmshavecommittedthemselvestothedeal,t
Aboutfiftyyearsago,plantphysiologistssetouttogrowrootsbythemselv
Aboutfiftyyearsago,plantphysiologistssetouttogrowrootsbythemselv
Aboutfiftyyearsago,plantphysiologistssetouttogrowrootsbythemselv
Aboutfiftyyearsago,plantphysiologistssetouttogrowrootsbythemselv
Aboutfiftyyearsago,plantphysiologistssetouttogrowrootsbythemselv
Aboutfiftyyearsago,plantphysiologistssetouttogrowrootsbythemselv
Aboutfiftyyearsago,plantphysiologistssetouttogrowrootsbythemselv
Aboutfiftyyearsago,plantphysiologistssetouttogrowrootsbythemselv
随机试题
WriteonANSWERSHEETTHREEanoteofabout50—60wordsbasedonthefollo
下列活动,()不属于需求开发活动的范畴。A.跟据系统需求识别和确认系统功能 B
姜的各种饮片中,长于温中止痛、止泻和温经止血的是A.生姜B.生姜皮C.干姜D.炮
一小儿,女患者,11岁。患甲状腺癌,并有颈淋巴结转移。医生告诉患儿母亲,女孩需做
在开放经济条件下,紧缩性的经济政策将导致进口额增大,使国际收支状况恶化。()
企业年金所需费用由()共同缴纳。A.企业 B.个人 C.国家 D.地方政
论述我国小学课程设计的原则。
医疗机构的配制记录A.应能完整反映配制的各个环节 B.由操作人员及时填写 C
由小痣细胞组成,位于真皮内的是()A.交界痣 B.皮内痣 C.复合痣 D.
投资项目决策分析与评价的基本要求包括贯彻落实科学发展观、资料数据准确可靠和()
最新回复
(
0
)