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这么大热天,植物都要涂防晒霜了?

Can Plants Get Sunburned?

本期科学秀由Hover赞助播出
This episode of SciShow is brought to you by Hover.
植物需要阳光来维持生存
Plants need sunlight to live, but that doesn’t mean that more light always leads to healthier
但这并不意味着更多阳光会使嫩芽更健康
sprouts.
它们也会像我们一样屏蔽阳光中有害的辐射
They need to block out the Sun’s most harmful rays just like we do, or else their cells
否则它们的细胞会受到极大的损伤
could get seriously damaged.
植物需要吸收阳光进行光合作用
Plants need sunlight for photosynthesis, where the incoming light is absorbed by a pigment
这些阳光由叶绿素吸收 经一系列化学反应后生成可以提供能量的葡萄糖
called chlorophyll and is involved in chemical reactions that make glucose for energy.
但不是所有光都产生同样多的能量
But not all light is created equal.
不同颜色的光蕴含不同等级的能量 红光能量比绿光更少
Different colors of light carry different amounts of energy: red light is less energetic
绿光能量比蓝光与紫光的能量更少
than green light, which is less energetic than blue or violet light.
大部分可见光都可以被植物用来进行光合作用
Plants can use pretty much any color of visible light for photosynthesis, but chlorophyll
但是叶绿素几乎不吸收绿光
barely absorbs green light.
因此植物的茎叶都是绿色的
That’s why plant stems and leaves look green.
这也就是我们看到的颜色
And that’s just the light we can see.
在紫光之外是紫外光(UV)
Beyond violet is ultraviolet light, or UV.
紫外光线的能量足以破坏DNA中的分子键
And UV has enough energy to break bonds in molecules like DNA.
人们会被晒伤的原因也就在此紫外线可以破坏你皮肤细胞的DNA
That’s why it causes sunburns in humans: Ultraviolet light can damage the DNA in your
你的免疫系统便会杀死那些皮肤细胞
skin cells, and your immune system then kills those cells to try and prevent bigger problems
来避免产生癌症之类的疾病
like cancer.
你的身体会产生黑色素
Your body makes a dark pigmented molecule called melanin that absorbs UV light to protect
来保护你的皮肤
your skin from damage.
频繁地在阳光下暴晒会使你的皮肤细胞产生更多的黑色素来保护你
More sun exposure generally causes special skin cells to produce more melanin for more
但这也会让你变黑
protection, which is what makes you tan.
但是紫外线不仅仅对人有害
But UV light isn’t just harmful to humans; it can damage DNA or other organic molecules
它会破坏DNA或者包括植物细胞在内的其他有机生物体的分子
in lots of organisms, including plant cells.
讲真 植物一天到晚都在太阳下待着
I mean, plants are just sitting there in the sun all the time!
它们自己就是荫凉它们不能哪凉快哪凉快待着
They are the shade… they can’t move into the shade.
过多的紫外线甚至会扰乱光合作用它会破坏绿叶中捕获阳光能量的结构
Too much UV can even mess up photosynthesis, because it can damage structures that help
比如一些重要的蛋白质 叶绿素或者控制光合作用的基因
capture energy from sunlight, like important proteins, chlorophyll, or photosynthetic genes.
和人们产生黑色素来抵御阳光中的辐射一样
Just like humans make melanin to protect against the Sun’s rays, plants have ways of defending
植物也有自我保护的方法
themselves.
它们会产生一种吸收紫外线的黄酮类物质
They make a variety of compounds called flavonoids that absorb UV.
和人类一样如果植物在暴晒之前没有产生这些化学物质
And just like in humans, plants that haven’t built up enough of those chemicals before
它的细胞也会死亡
being exposed to lots of bright sunlight can end up with cell death and whitish burns on
或者它的叶子上会出现白色灼伤痕迹
their leaves.
这被称作焦叶病
It’s sometimes known as leaf scorch.
甚至有些人还说在白天给植物浇水
Some people even say that watering plants during the day makes them more susceptible
会使他们更容易得上焦叶病
to leaf scorch.
因为水滴就像一个微型透镜
The reasoning goes: the water drops act like little lenses that focus sunlight down to
把阳光聚焦在植物叶片上成为发热点
hot points all over the plant’s leaves.
就像用放大镜去点蚂蚁一样
Like frying ants with a magnifying glass.
但是科学家们通过实验发现
But when scientists tested this out, they found that it just doesn’t work like that
对大多数植物来说事实并非如此
for most plants.
水滴的形状大小各不相同但没有一滴足以将折射阳光到合适的角度
Water droplets vary in shape and size too much, and none of the drops bend light enough
来使阳光聚焦在它们所在的叶片上
to focus it on the surface of the leaves they’re already sitting on.
所以即使植物比我们需要更多的阳光
So even though plants might need sunlight more than us, they can still get a little
在没有保护的情况下它们也是可以被烘烤一下的
toasted if they don’t have enough protection.
你想为你的博客 商店 创业来一个网站吗
Do you need a website for your blog/store/startup?
使用Hover能保证你拥有一个最好的域名
Make sure it has the best domain possible by using Hover, an easy way to set up your
Hover有最简便的方法与最流行的网站制作师帮你建立一个域名
domain name with the most popular website builders.
Hover给客户提供真人服务
Hover provides customer service from actual humans, and has over 400 domain extensions,
并且有超过四百个新域名后缀比如.COM .NET 更棒的是.PIZZA
like dot-COM, dot-NET, and better yet, dot-PIZZA.
我没有开玩笑哦
I’m not even kidding.
拥有一个完美的域名意味着你可以做很酷的客户邮箱
Securing the perfect domain means you can make cool custom email address, as well as
或者很酷的网站
a cool website.
我曾经买过nk.cm的域名所以我的邮箱名可以是“h@nk.cm”
I once bought nk.cm so that my email could be “h@nk.cm,”but then I stopped using it,
但是后来我不用它了因为人们都被弄糊涂啦
cause it really confused people a lot!
想为你的想法来一个域名吗来hover.com/scishow吧
To get a domain name for your idea, go over to hover.com/scishow.

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视频概述

人会被晒伤,以阳光为生的植物会不会呢?来自Hover的SciShow会告诉你答案!

听录译者

收集自网络

翻译译者

一晴方觉夏至深

审核员

【MR】Metro

视频来源

https://www.youtube.com/watch?v=ds7n-LbOY4M

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