Why Are There No Holes Around Trees? · Kurzgesagt – In a Nutshell
揭秘树木如何在不挖洞的情况下生长，了解它们如何通过光合作用吸收空气中的碳，适合练习自然、科技和成长相关词汇。
Trees are the heaviest and largest living things on Earth, with the most massive tree weighing almost 2,000 tons – as much as ten blue whales.
树木是地球上最重、最大的生物；其中最庞大的树木重量接近2000吨，相当于十头蓝鲸的重量总和。
But instead of floating weightlessly in the ocean it reaches 25 stories into the sky, held in place by surprisingly shallow roots.
然而，它并没有在海洋中无重地漂浮，而是直插云霄（高度相当于25层楼），依靠那些出人意料地浅的“根系”固定在原地。
You’d think trees grow from the ground
你可能会以为树木是从地面长出来的。
because, well, they are made of stuff and there is stuff in the ground – but if something so massive and huge ate something down below,
因为，它们毕竟是由某种物质构成的，而地下也确实存在这些物质；不过，如果有什么极其庞大、强大的生物把地下的东西“吃”掉了的话……
it would have to leave holes.
它肯定会在某些地方留下空洞（或缝隙）。
Instead trees are growing by literally eating thin air!
实际上，树木是通过“吸收”空气中的养分来生长的！
But this is only half of the story because down in the ground, roots are mining rocks in ways weirder than you can imagine.
但这只是故事的一半：因为在地下，植物的根系以一种你难以想象的方式“挖掘”岩石。
How does this work?
这是如何运作的？
How to Eat Air to Grow Huge Carbon is the most valuable material for living things.
如何通过‘吸收空气’来生成大量的碳？”——这种物质对所有生物来说都是极其宝贵的。
A chemical multi tool you can make almost everything from – and a good amount of it just floats around in the air and the oceans.
这是一种具有多种化学功能的“多功能工具”；你可以用它制造几乎所有东西。不过，其中很大一部分化学物质其实就漂浮在空气中以及海洋中。
What makes plants so incredibly successful is that over a billion years ago their ancestors became better than any other living thing at harvesting carbon.
植物之所以能够取得如此巨大的成功，原因在于：在超过十亿年前，它们的祖先就已经在吸收碳方面超越了其他所有生物。
They used it to grow and grow and grow.
他们利用它不断进行繁殖（即让这个生物或系统不断“生长”）。
Today plants make up 80% of the
如今，植物占据了……（原文未完成）
biomass on earth and are the basis for all complex life – all animals eat either plants or animals that eat plants,
地球上的生物量是所有复杂生命形式的基础；所有动物要么直接以植物为食，要么以以植物为食的动物为食。
to get the carbon they need.
为了获取所需的碳元素。
Trees are an especially ingenious way plants found to harvest massive amounts of carbon.
树木是植物用来吸收大量碳的一种极其巧妙的方式。
Trees are big and heavy and so they need a lot of material.
树木体积庞大且重量很重，因此它们需要大量的材料来支撑自己的生长。
But the atmosphere is only about 0.04% CO₂.
但大气中的二氧化碳含量仅约为0.04%。
425 CO₂ molecules per million molecules in the air.
空气中每百万个分子中含有 425 个二氧化碳分子。
To get a single tonne of carbon a tree has to process 6000 tons, or 5 million cubic meters of air!
为了吸收一吨二氧化碳，一棵树必须处理总共 6000 吨（即 500 万立方米）的空气！
This is a lot.
这数量确实很大。
So trees developed sophisticated biological industrial megalopolises: Their crowns.
因此，树木形成了复杂的“生物工业都市”——也就是它们的树冠部分。
A huge industrial park network, made from
一个庞大的工业园区网络，由……构成。
dozens of branches, subbranches and hundreds of thousands of twigs that can sense the sun and shape the tree to grow towards it in slow motion.
这棵树拥有数十个主枝和次级枝条，以及数十万根细小的枝梢；这些枝梢能够感知太阳的方向，并通过缓慢的运动来调整树的生长方向，使其朝向太阳生长。
They are carrying up to a million
它们的数量多达一百万。
leaves, the industrial parks where a tree
树叶……还有那些工业园区里，那里连一棵树都没有。
eats and builds, consuming extreme amounts of
它通过进食来获取能量，并进行自身的生长与发育；在此过程中会消耗大量的资源（或物质）。
resources from the air and fed by the roots down below while vomiting waste and changing the climate around them.
它们从空气中获取养分，通过根部将养分输送到植株的各个部分；同时会排出废物，并改变周围的气候环境。
Let’s zoom into a single leaf.
让我们把镜头放大，仔细观察一片树叶。
It is made from hundreds of millions
它是由数亿个部件组成的。
of factory cells and optimized to have as much surface area and be as thin as possible to harvest sunlight.
这些工厂化制造的电池单元经过优化设计，旨在尽可能增大表面积并降低厚度，从而更有效地吸收阳光能量。
While your skin is hundreds of cells thick, a leaf can be just ten cells top to bottom.
虽然你的皮肤由数百层细胞构成，但一片叶子的厚度可能只有10层细胞（从上到下）。
On their top leaves have only a single, ultra thin layer of protective transparent “skin” cells that let light through and keep water in.
它们最上层的叶片仅覆盖着一层极其薄的保护性透明细胞膜。这种细胞膜既能让光线透过，又能防止水分流失。
Below them are layers of factory cells, filled to the brink with chloroplasts that do the actual work.
在他们下方，是一层层的工厂细胞；这些细胞内部充满了叶绿体，而叶绿体才是真正执行光合作用（即制造能量的过程）的器官。
Beneath them a spongy layer of loose cells enables gases to travel around.
在他们下方，有一层由松散细胞构成的海绵状结构，这种结构能够让气体在其中自由流动。
The whole leaf is traversed by a network of vein-like superhighways, that carry sugars back down and bring water and minerals up from the roots.
整片叶子上布满了类似“高速公路”的脉络网络：这些脉络将糖分输送到叶片的下方，同时将水分和矿物质从根部输送到叶片的上方。
At the bottom is another protective layer
在底部还有一层保护层。
of cells interrupted by hundreds of thousands of stomata – tiny mouths opened and closed by two guard cells that look a bit like lips.
这些细胞被成千上万个气孔所分隔；气孔是那些微小的开口结构，它们的开合由两个被称为“保卫细胞”的结构控制，这两个保卫细胞的外观有点像嘴唇。
Each day an adult tree pulls up dozens of liters of water all the way from its roots in the ground to these veins,
每天，一棵成熟的树木都会从地下的根部吸收数十升的水分，并将这些水分输送到自身的“脉络”（即树木内部的导管系统）中。
where about 95% of it is sweated out through hundreds of billions of these tiny mouths.
其中大约95%的水分是通过这些数以千亿计的微小“嘴巴”被排出的。