Germination and Growth of a seed 托福紅Delta聽力原文翻譯及問題答案

Germination and Growth of a seed 托福紅Delta聽力原文翻譯及問題答案，今天中國教育在線就來為大家分析這個(gè)問題。

一、Germination and Growth of a seed 托福紅Delta聽力原文：

Our study of the life cycle of a plant usually starts with the germination of a seed.The seed contains the hereditary information the plant needs to grow.It also contains enough food to nourish itself during germination.

Heredity—the genes inherited from the parent plant—decides several things about the life of the plant.Heredity determines what the plant will look like,how it will grow,and what kind of seeds it will bear.Inside the seed is all the genetic information the plant needs to grow to maturity.An individual plant’s survival depends partly on its hereditary characteristics.But a plant depends on more than just heredity.It needs the outside world to supply its daily needs:sunlight,carbon dioxide,nutrients,and water.

Some seeds germinate as soon as they’re in a suitable environment.Other seeds remain dormant and won’t germinate until a specific environmental cue causes them to“wake up”and come out of dormancy.Seeds of desert plants germinate only after a heavy rainfall.If they germinated after a slight rain,the soil might soon be too dry to support the seedlings.Seed dormancy increases the chances that germination will take place at a time and place that are best for the seedling.

Germination begins when water penetrates the seed’s outer coating and reaches inside to the live embryo.Water is a basic requirement,and no seed will germinate unless it absorbs water.This is because the embryo inside the seed is dehydrated,and cells need water for active metabolism.Water is the substance in which most of the chemical reactions of the plant take place.

For a seed to sprout and grow,it needs a great deal of energy.Seeds get this energy by converting the energy of their stored fuel molecules,and this requires oxygen.Germination also requires a certain combination of temperature and light,which,in North America,is triggered by the start of spring.Some seeds respond early in the season,others much later.Each plant species has an ideal temperature at which the largest number of seeds will germinate.

When the embryo takes in water,it often swells to several times its original size.It gets this first burst of energy by tapping its own food stores.Eventually,the seed expands enough to rupture its coating and burst through the seed case.

The first organ to emerge from the germinating seed is the embryonic root.The root pushes outward into the soil and anchors the seedling.Now the seedling begins to gather up water and nutrients through thousands of tiny hair-like roots.After a certain period,the seedling sprouts upward.The tip of the shoot has to break through the soil surface.Light is the environmental cue that tells the seedling when it’s broken ground.Only when the seedling senses light will it straighten up and begin to grow taller.As it straightens up and grows,it unfolds its solar collectors,its first leaves.Once the seedling has its main leaves,it doesn’t need its embryonic food stoics anymore because now it draws most of its growth energy directly from the sun.

The germination of a seed is a critical stage in the plant’s life cycle.The tough seed becomes a fragile seedling,and only a small fraction of seedlings survive long enough to become parent plants.Because the chances of a seedling’s survival arc so low,plants make up for this by producing enormous numbers of seeds.

二、Germination and Growth of a seed 托福紅Delta聽力中文翻譯：

我們對植物生命周期的研究通常從種子發(fā)芽開始。種子含有植物生長所需的遺傳信息。它還含有足夠的食物，可以在發(fā)芽期間自我滋養(yǎng)。

遺傳從親本植物遺傳下來的基因決定了植物生命的幾個(gè)方面。遺傳決定了植物的長相、生長方式和種子種類。種子內(nèi)部是植物生長成熟所需的所有遺傳信息。單個(gè)植物的存活部分取決于其遺傳特性。但植物不僅僅取決于遺傳。它需要外部世界來滿足日常需求：陽光、二氧化碳、營養(yǎng)和水。

有些種子在合適的環(huán)境中一發(fā)芽。其他種子保持休眠狀態(tài)，直到特定的環(huán)境線索使它們“醒來”并從休眠狀態(tài)中出來，才會(huì)發(fā)芽。沙漠植物的種子只有在大雨后才能發(fā)芽。如果它們在小雨后發(fā)芽，土壤可能很快就會(huì)太干，無法支撐幼苗。種子休眠增加了在最適合幼苗生長的時(shí)間和地點(diǎn)發(fā)芽的機(jī)會(huì)。

當(dāng)水滲透到種子的外層并到達(dá)活胚的內(nèi)部時(shí)，種子開始發(fā)芽。水分是一種基本的需求，除非種子吸收水分，否則種子不會(huì)發(fā)芽。這是因?yàn)榉N子內(nèi)的胚胎脫水，細(xì)胞需要水來進(jìn)行活躍的新陳代謝。水是植物大多數(shù)化學(xué)反應(yīng)發(fā)生的物質(zhì)。

種子發(fā)芽和生長需要大量的能量。種子通過轉(zhuǎn)換儲(chǔ)存的燃料分子的能量來獲得這種能量，這需要氧氣。發(fā)芽還需要一定的溫度和光照組合，在北美，這是春天開始時(shí)觸發(fā)的。有些種子在這個(gè)季節(jié)很早就有反應(yīng)，另一些則要晚得多。每種植物都有一個(gè)理想的溫度，在這個(gè)溫度下，最多的種子將發(fā)芽。

當(dāng)胚胎吸水時(shí)，通常會(huì)膨脹到原來大小的幾倍。它通過利用自己的食物儲(chǔ)備獲得第一次爆發(fā)的能量。最終，種子膨脹到足以使其外殼破裂并穿透種子盒。

從發(fā)芽的種子中出現(xiàn)的第一個(gè)器官是胚根。根向外伸入土壤并固定幼苗?，F(xiàn)在，幼苗開始通過數(shù)千根毛發(fā)狀的細(xì)根收集水分和養(yǎng)分。經(jīng)過一段時(shí)間后，幼苗向上發(fā)芽。莖尖必須穿透土壤表面。光是告訴幼苗何時(shí)破土的環(huán)境線索。只有當(dāng)幼苗感覺到光時(shí)，它才會(huì)變直并開始長高。隨著它變直和生長，它展開了它的太陽能收集器，它的第一片葉子。一旦幼苗有了主葉，就不再需要它的胚胎食物禁欲了，因?yàn)楝F(xiàn)在它的大部分生長能量都直接來自太陽。

種子的萌發(fā)是植物生命周期中的一個(gè)關(guān)鍵階段。堅(jiān)韌的種子會(huì)變成脆弱的幼苗，只有一小部分幼苗能夠存活足夠長的時(shí)間成為親本。因?yàn)橛酌绱婊畹臋C(jī)會(huì)很低，植物通過產(chǎn)生大量種子來彌補(bǔ)這一點(diǎn)。

三、Germination and Growth of a seed 托福紅Delta聽力問題：

Q1:What aspect of seeds does the professor mainly discuss?

A.Hereditary changes in seeds

B.Ways that seeds are dispersed

C.Genetic engineering of seeds

D.How seeds germinate and grow

Q2:What role does heredity play in the life of a plant?

A.It provides the information the plant needs to grow.

B.It helps nutrients move up from the soil into the plant.

C.It causes the seed to swell and burst out of its case.

D.It supplies the energy required to manufacture food.

Q3:Why does the professor say this:

A.To point out the diversity of plant life

B.To give an example of an environmental cue

C.To compare different ecosystems where plants live

D.To explain why few plants survive in the desert

Q4:What environmental factors are required for a seed to germinate?

Click on two answers.

A.Heredity

B.Water

C.Organic fertilizer

D.The proper temperature

Q5:How does a seed obtain the energy it needs for germination?

A.It takes in nutrients through capillaries in its roots.

B.It depends on the chemical energy from fertilizer.

C.It converts the energy of food stored within itself.

D.It uses solar energy collected through its leaves.

Q6:The professor explains how a seed becomes a young plant.Summarize the process by putting the events in order.

Drag each sentence to the space where it belongs.

A.The plant collects sunlight for its growth energy.

B.The embryonic root pushes outward into the soil.

C.The seed takes in water and begins to swell.

D.The tip of the shoot breaks through the soil’s surface.

四、Germination and Growth of a seed 托福紅Delta聽力答案：

A1:正確答案：D

A2:正確答案：A

A3:正確答案：B

A4:正確答案：BD

A5:正確答案：C

A6:正確答案：CBDA

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