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分泌金属树液的树 – 译学馆
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分泌金属树液的树

This Tree Oozes Metal Sap

[INTRO ♪]
[前奏♪]
事实
The South Pacific island of New Caledonia
南太平洋的新喀里多尼亚岛上有一种植物
has one of the weirdest plants on Earth.
是地球上最奇怪的植物之一
It’s a tree whose sap is this teal-ish, blueish-green color
它的树液呈蓝绿色
that you don’t usually see in nature
这个颜色很难在自然界中见到
— especially not in living things.
尤其不会在生物上见到
But as alien as it looks,
不过尽管它看起来很诡异
the green color is totally natural,
这种蓝绿色却是完全天然的
and it comes from the fact that
这种颜色的形成原因是
more than a quarter of the sap… is metal.
它树液中超过25%的成分是金属
The tree is called Pycnandra acuminata,
这种树叫做尖尾木桐
and it grows in the rainforests in what are called ultramafic soils.
它生长在热带雨林的超镁铁质土壤中
Ultramafic soils are sort of unusual
超镁铁质土壤有点不太常见
because they form from rocks with large concentrations of nickel.
它们由富含镍的岩石形成的
And rocks like that are rare
这种岩石非常罕见
—you typically only see them in places
通常只形成于
where material from the Earth’s mantle has been pushed to the surface.
地幔物质被带到地表的地方
In general, that type of soil is also pretty hard for plants to grow in.
一般来说 这类土壤相当不适宜植物的生长
Even though they need a little bit of nickel to survive,
因为虽然微量的镍是植物生长所必需的
too much of it is typically toxic.
但过量却会使植物镍中毒
That’s because nickel has a similar chemical structure
因为镍与植物生长所需的其他营养元素
to other nutrients plants need to grow,
比如钙和镁
like calcium and magnesium,
有着相似的化学结构
so plants can end up absorbing nickel
所以植物可能会吸收过多镍
instead of some of the other nutrients they need.
而不吸收所需的其它营养元素
All that nickel can mess with their metabolism
而过量的镍会干扰植物的新陈代谢
and stunt their growth
就算没有直接杀死它们
—if it doesn’t just straight-up kill them.
也会阻碍植物的正常生长
But the roots of Pycnandra acuminata guzzle up that metal,
而尖尾木桐的根会疯狂吸收镍
and the plant has about 250 grams of nickel per kilogram of sap.
其每千克树液中约含250克镍
That’s around 250 thousand times more than your average plant.
相当于一般植物的大约25万倍
It also happens to be enough to turn its sap green.
这个含量恰好使其树液呈蓝绿色
But this tree doesn’t seem to mind.
尖尾木桐似乎并不介意过量的镍
That makes it a metal hyperaccumulator
这使它成为重金属超累积型植物
—in other words, a plant that can deal with a lot of metal.
换句话说 一种能够处理大量重金属的植物
These plants deal with nickel
尖尾木桐通过
by capturing it with molecules called ligands,
将配体分子与镍原子结合
which bind to nickel atoms and prevent them from reacting with other chemicals.
来防止镍原子和其他化学元素发生反应
That helps keep the plant’s chemical structure intact
使这种植物在高浓度镍的环境里
despite all that extra metal.
仍保持化学结构不被破坏
Pycnandra acuminata also basically
尖尾木桐还有另一种方法
quarantines the nickel in cells that are separate from other parts of the plant.
简言之就是将镍隔离于远离其他部位的细胞中
And those solutions seem to work out for this tree.
这些应对重金属的对策似乎挺有效
The question is why plants like these
但为什么这类植物
have evolved to store so much metal,
会进化出储存如此多重金属的功能
and scientists haven’t figured out the exact reason.
科学家还没有找到确切的原因
One possibility is that
一种可能的原因是
it evolved as a way of surviving extremely metallic soils.
它们为了在富含重金属的土壤中生存
But scientists think it’s now what’s called an exaptation
这种现象目前被科学家们称为功能变异
—a trait evolved for one purpose
意思是因一个目的进化出的特性
but now serves a different one.
但是后来实现了另一个目的
For example, one hypothesis suggests
例如 一种假说认为
that plants build up all this nickel
植物累积这些镍是为了
to protect themselves from predators,
保护自己免受掠食者的侵害
since nickel is toxic to animals as well plants.
因为镍对动植物有毒性
But the case isn’t closed.
但这不是最终结论
While there’s evidence that some insects are sensitive to high levels of nickel in plants,
虽然有证据表明某些昆虫对植物中高浓度的镍很敏感
larger plant-eaters don’t seem to be put off by it at all.
但体型较大的食草动物却似乎完全不受影响
So there may be a different reason plants have this trait,
因此 植物聚集镍可能有另一个原因
and another hypothesis suggests that
这种假说认为
the nickel is a type of chemical attack on other plants
聚集镍是对其他植物的一种化学攻击
—something called allelopathy.
这种现象称为植化相克
The idea is that when a hyperaccumulator’s leaves drop to the ground,
这种观点认为当超积累植物的叶子落到地上
they enrich the nickel in the soil
土壤中的镍含量增加
and make it harder for other plants to thrive.
这导致其它植物难以生长
Its young offshoots may have a better chance of surviving
使得超积累植物的后代有更多存活机会
if they don’t have to compete with other plants for resources.
因为它们不必与其他植物竞争资源
But while there’s some evidence for it, this idea isn’t proven yet either.
不过虽然有证据支持 这个想法也没有被证实
Whatever its reason for being the way it is,
不管尖尾木桐聚集镍是出于什么原因
this bizarre tree could offer us more than its weirdness.
这一怪异的植物带给我们的不仅仅是其奇特性
Metal hyperaccumulators like it
这类超积累植物
could make it possible to remove metal pollutants from soils,
能帮助我们去除土壤中的重金属污染物
which could be valuable here on Earth
这不仅在地球上很有意义
or even in future civilizations on Mars.
甚至在未来的火星文明中都很有价值
But we have to protect this tree
我们必须保护这种树
because there are only a few hundred left,
因为现在只剩下几百棵了
and we still have plenty more to learn from it.
而我们要从它这里学习的还有很多
[OUTRO ♪]
[尾声♪]

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视频概述

为什么这种树会分泌金属树液

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收集自网络

翻译译者

CidEr酒神

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审核员LJ

视频来源

https://www.youtube.com/watch?v=4z-kG9DCzUI

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