The Green Planet （Part Two）绿色星球（二）

上期我们了解了北极圈和赤道的不同生态风景，也领略了冰雪世界与热带雨林的极致反差，本期我们将走进水生植物与沙漠植物，带大家领略极端环境中的植物是如何绝地求生的。

剧情简介

植物在与动物建立互惠关系的同时，也展现了与其他生物一样的攻击性、竞争性。为争夺光照、空间、营养和繁殖的机会，它们与竞争对手展开激烈的生存斗争。这部纪录片透过全新科技呈现了二十多年来的新发现，深刻揭示了植物世界紧密相连的一面，将观众带入了一个超越人眼观察的深入角度，让人们从植物的角度看待地球。

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A

在含氧量极高的绿色水生世界，河床岩石上生长着一片粉色的水生植物——虹河苔，也被称作“瀑布兰花”。这片粉色羽毛般的丝状物，造就了卡诺克里斯塔莱斯河——地球上最美的河流之一。

Plants cover much of the land surface of our planet. But thereis another 1）extraordinary green world， that is often hidden from us.It’s one where plants have 2）overcome huge challenges in order tosurvive. At first sight， a lake like this would seem to have everything that life needs in order to 3）thrive—clear，oxygen-rich water， plenty of dissolvednutrients and minerals and lots of sunlight.But in fact， life in fresh water presents plantswith huge problems. To succeed， plants havehad to abandon many of the adaptations thatserved them so well on land， and 4）evolvesomething quite new. And in doing that， theyhave created some of the most beautiful andbizarre and important 5）habitats on earth.

There are few places where it’s moredifficult to make a 6）permanent home thana freshwater 7）torrent like this one. Violentcurrents 8）rip across the riverbed， scouring itclean， ripping land plants from their 9）marginsand drowning them. How could any plantsurvive in a place like this？ Yet， even here，some do manage to， quite literally， holdon！ They can grasp the 10）bare rock withremarkable strength. This ability allows plants to thrive in these otherwise 11）hostile environments.

This is the Cano Cristales River in Columbia. These plants are RedMacarenia， sometimes called the “Orchid of the Falls”. They 12）cling to theriverbed， not with their roots， but with their stems， blued to the rock surfaceby one of the most powerful adhesives in nature. The rock itself will breakbefore these anchors lose theirgrip. These feathery filaments， aretheir modified leaves. And they dowhat roots normally do—gatherthe minerals and nutrients theyneed that are dissolved in thewater.

With such 13）spectacular colors，it’s hardly surprising that the CanoCristales is sometimes called “themost beautiful river on earth”.

植物覆盖了地球的大部分陆地表面，不过还有一个非凡的绿色世界往往会被我们忽视。在这个世界里，植物需要应对巨大的挑战才能获得一线生机。乍看起来，这样的湖泊似乎拥有生命繁衍生息所需要的一切条件——清澈而含氧量高的水、大量溶解于水的营养物质和矿物质，以及充足的阳光。然而事实上，淡水之中的植物，需要面对巨大的生存挑战。为了生存和繁衍，植物不得不放弃许多针对陆生环境的适应性改变，并发展出一些新的特征。在此过程中，它们也为地球创造了一些奇妙景致，一些发挥着关键作用的栖息地。

很难想象，像这样的淡水急流，能为一些植物创造出永久的栖息地。在激流之下，河床被冲刷得干干净净，就连长在河床边的植物也被冲刷下来，随波逐流。植物怎么可能在这样的环境中生存下来呢？然而，即便这里的环境如此恶劣，一些植物还是坚持了下来。它们能以惊人的力量，把自己固定在裸露的岩石上。这种能力使得一些植物可以在这些看似不可能的环境中生长。

这是位于哥伦比亚的卡诺克里斯塔莱斯河。这些植物是虹河苔，它们有时候也被称为“瀑布兰花”。帮助它们附着在河床岩石上的，不是它们的根，而是它们的茎。它们可以分泌一种自然界中最强的黏合剂。在长时间的黏合腐蚀之下，岩石会发生分解。这些羽毛般的丝状物，是虹河苔发生形变的叶子。它们可以像普通植物的根系一样，收集溶解在水中的矿物质和营养物质。

因为有着如此绚烂的色彩，卡诺克里斯塔莱斯河有时也被称为“地球上最美的河流”。

考点解析

原文：It’s one where plants have overcome huge challenges in order to survive.

1. in order to do sth 是to do sth 的变体。用in order to do sth 表示目的时，它既可以用于句首，也可用于句末；用于句首时，其强调意味较浓。

【例】She arrived early in order to get a good seat.

她到得很早，只为占个好座位。

In order to get into a good school， I must study even harder.

为了考入一所好学校，我必须更加努力。

2. in order to do sth 的否定形式是in order not to do sth，意思是“为了不……; 以免……”。

【例】Please reply at once in order not to lose this opportunity.

为了不失去这次机会，请立即回复。

3. in order to 和in order that 均可表示目的，区别是前者引出不定式短语，后者引导目的状语从句。与in order to do sth 表示目的的情形相似，in orderthat 引导的目的状语从句可以位于主句之前或之后。

【例】These men risk their lives in order that we live more safely.

这些人甘冒生命危险，为的是让我们的生活更安全。

4. so as to 和so that 也可表示目的，区别是前者引出不定式短语，后者引导目的状语从句。与用so as to do sth 表示目的的情形相似，so that 引导的目的状语从句通常位于主句之后。so that 有时可省略其中的that。

【例】They wrote the notices in several languages so that foreign tourists could understand them.

他们用几种语言写公告牌，以便让各国游客都能看得懂。

Leave the keys out so （that） I remember to take them with me.

把钥匙放在外面，我好记得带。

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B

你应该听说过藻类，但你见过篮球那么大的圆形湖球藻吗？在北海道的阿寒湖，不仅有美丽的天鹅，还有一种神奇的湖球藻。这种湖球藻是如何生存的呢？

The frozen water world of Lake Akan， in northern Japan， home to oneof the strangest and most 14）primitive of plants. It’s an alga， like those thatappear so 15）mysteriously in our ponds. But this one is truly extraordinary.Each spring， the melting ice releases soft， velvety balls of 16）interwoventhreads， called Marimos.

This one is small， no bigger than a walnut. But there are lots of themhere. They attract the attention of visiting whooper swans. But there is oneway for the Marimos to escape from the danger， and it depends on a changein the weather. Fortunately in the spring， winds sweep across the lake，creating currents that carry some of the Marimos beyond the reach of hungryswans.

It’s a start of a remarkable journey. They are gently carried back and forthby the currents， so that the Marimos become more and more 17）spherical.And slowly， they travel into deeper water. Here there are great numbers ofthem， certainly many millions！ Some are thesize of basketballs. They are safe fromswans and the water is stil 18）shallow enough for some sunlight to reach them. It seems a perfect home. And so itis， almost.