首页
登录
职称英语
Most growing plants contain much more water than all other materials combin
Most growing plants contain much more water than all other materials combin
游客
2024-06-03
10
管理
问题
Most growing plants contain much more water than all other materials combined. C.R. Dames has suggested that it is as proper to term the plant a water structure as to call a house composed mainly of bricks as a brick building. It is certain that all the essential processes of plant growth and development occur in water. The mineral elements from the soil that are usable by the plant must be dissolved in the soil solution before they can be taken into the root. They are carded to all parts of the growing plant and are built into essential plant materials while in a dissolved state. The carbon dioxide (CO2) from the air may enter the leaf as a gas but is dissolved in the leaf before it is combined with a part of the water to form simple sugars — the base material from which the plant body is mainly built. Actively growing plant parts are generally 75 to 90 percent water. Structural parts of plants, such as woody stems no longer actively growing, may have much less water than growing tissues.
The actual amount of water in the plant at any one time, is only a very small part of what passes through it during its development. The processes of photosynthesis (光合作用), by which carbon dioxide and water are combined — in the presence of chlorophyll (叶绿素) and with energy derived from light — to form sugars, require that carbon dioxide from the air enter the plant. This occurs mainly in the leaf. The leaf surface is not solid but contains great numbers of minute openings, through which the carbon dioxide enters. The same structure that permits the one gas to enter the leaf, however, permits another gas — water vapor — to be lost from it. Since carbon dioxide is present in the air only in trace quantities (3 to 4 parts in 10,000 parts of air) and water vapor is near saturation in the air spaces within the leaf (at 80F, saturated air would contain about 186 parts of water vapor in 10,000 parts of air), the total amount of water vapor lost is many times the carbon dioxide intake. Actually because of wind and other factors, the loss of water in proportion to carbon dioxide intake may be even greater. Also, not all of the carbon dioxide that enters the leaf is synthesized into carbohydrates. [br] According to the passage, which of the following statements is TRUE?
选项
A、The woody stems contain more wafer than the leaves.
B、Only part of the carbon dioxide in the plants is synthesized.
C、The mineral elements will not be absorbed by the plant unless dissolved in their roots.
D、Air existing around the leaf is found to be saturated.
答案
B
解析
是非判断型细节题。参见全文最后一句:并非所有进入叶子的二氧化碳都会合成碳水化合物。此句意与选项B一致(植物中的二氧化碳只有一部分被合成)。
转载请注明原文地址:https://tihaiku.com/zcyy/3617343.html
相关试题推荐
Ithasbeenknownsinceancienttimesthatcertainplantsregularlyopenthe
Ithasbeenknownsinceancienttimesthatcertainplantsregularlyopenthe
[originaltext]Themarketisaconcept.Ifyouaregrowingtomatoesinyour
[originaltext]Themarketisaconcept.Ifyouaregrowingtomatoesinyour
[originaltext]Botany,thestudyofplants,occupiesapeculiarpositionint
Onlywithcombinedefforts,______.(我们才能期望我们的国家有新的面貌).canweexpectourcountr
ThehomelessmakeupagrowingpercentageofAmerica’spopulation.【C1】______
ThehomelessmakeupagrowingpercentageofAmerica’spopulation.【C1】______
ThehomelessmakeupagrowingpercentageofAmerica’spopulation.【C1】______
ThehomelessmakeupagrowingpercentageofAmerica’spopulation.【C1】______
随机试题
Thepassageismainlyabout______.[br]AccordingtothepollbytheNationalSl
患者,男性,75岁,因“慢性阻塞性肺疾病(COPD)急性发作”入院,给予抗感染等
逆向思维也叫求异思维,它是对司空见惯的似乎已成定论的事物或观点反过来思考的一种思
(2016年真题)()年10月28日,十届全国人大常委会第五次审议通过了《
A.实证B.虚证C.虚实夹杂证D.真虚假实证E.真实假虚证实邪结聚,阻滞经络,气
健康婴幼儿粪便中主要细菌正确的是A.双歧杆菌、拟杆菌、肠杆菌、肠球菌、葡萄球菌B
学校全面实现教育目的的基本途径是()A.班主任工作 B.学科教学 C.
臌胀之瘀结水留证的代表方是A.失笑散 B.膈下逐瘀汤 C.旋覆花汤 D.调
甲(男)、乙(女)是男女朋友,后因感情不和,乙提出分手,甲则将其二人同居时的亲热
若项目融资采用股权式合资经营模式,则后期投资者加入该项目()。A:必须成为控股股
最新回复
(
0
)