这种植物的绒毛为何如此致命？What Makes This Plant Hair So Deadly?

这种植物的绒毛为何如此致命？What Makes This Plant Hair So Deadly? 
When you hear the phrase "killer hair", you probably picture a sick mullet -- you know, some super cool will do.
一提到“杀手发型”，你可能会立刻想到一个超炫的莫西干发型——你懂的，那种特别酷的人会留的发型。
You'd probably never mistake it for anything literal.
你大概永远不会真的把它理解成字面上的意思。
But, if you venture outside the mammalian branch of the tree of life and onto another limb, you'll find the owners of some truly “killer hair”.
但若你走出哺乳动物这一枝系，探索生命之树的另一分支，你将会遇见一些拥有真正“致命毛发”的主人。
From switching on the immune system to fighting off insects in the most metal way possible, here's what plants do with their killer dos.
从激活免疫反应到以极其强悍的手段驱避昆虫，这些就是植物利用它们“致命毛发”所做的事情。
So what we're actually talking about here are tiny protrusions called trichomes, and a wide variety of plants have them on their stems, leaves, and other surfaces.
因此，我们讨论的实际上是一种被称为毛状体的微小结构，各种植物的茎、叶以及其他部位表面都长有这些结构。
While they generally resemble tiny hairs, they come in a handful of varieties -- some even secrete chemicals to help the plant defend itself.
虽然它们通常形似细小的毛发，但实际上毛状体有好几种不同形态——其中一些还能分泌化学物质以起到辅助作用，使植物能够自我保护。
And that's only the beginning of what a bunch of teeny tiny hairs can do.
这仅仅是这些细小毛发所能发挥作用的冰山一角。
For example, how does growing more food with less water sound?
例如，减少用水的同时还能增加食物产量听起来怎么样？
In a 2017 study in the journal Rice -- yes, that's a journal -- researchers bred a gene into a domesticated strain of rice that caused them to grow more trichomes on their leaves.
2017年发表于《米饭》杂志的一项研究（没错这是一个杂志）显示，科研人员将一个特定基因导入家种水稻中，使其叶片长出了更密集的绒毛。
Their "hairy" strain lost less water during photosynthesis compared to the original, though the plants also got hotter during the day.
这种“多毛”品种的水稻在进行光合作用时，相比原来的品种损失的水分更少，不过在白天植株温度也相应升高了。
The researchers think that the extra hairs are affecting something called the boundary layer, which is a layer of air around the leaf, and are making it harder for water to pass through and escape the leaf.
研究者们认为，这些额外的茸毛影响了叶片周围被称为边界层的空气层，这让水分更难叶片并从中蒸发。
They hope this could help us develop crops that resist drought or require less water, which could be useful in the future!
研究人员期望此发现有望促进开发耐旱或低水耗的农作物，这一点在未来或许极为重要！
But if unlike me, you've ever had to use a blow dryer, maybe you're thinking, yeah,
但你可能与我不一样，你可能用过吹风机，或许你就会想，没错，
I know hair traps water.
我明白头发能够锁住水分。
Don't worry -- I'm just getting started.
别着急，我这才刚刚开始。
Trichomes in Arabidopsis, a plant in the mustard family and darling of the plant genetics world, not only help the plant detect rain -- they also help it fire up its immune system.
拟南芥的表皮毛细胞，作为植物遗传学领域的明星，不但能感应雨水，还能促进植物免疫系统的启动。
Publishing in the journal Nature Communications in 2022, researchers showed that trichomes are able to detect the physical impact of raindrops, as well as other mechanical signals.
2022年发表于《自然通讯》的研究显示，拟南芥的表皮毛细胞不仅能感应雨滴的撞击力，也能检测其他种类的机械信号。
Once the trichomes detect the raindrops, they send out a pulse of calcium to the surrounding cells.
当表皮毛细胞察觉到雨滴时，它们便会向邻近细胞发送一阵钙离子脉冲。
That pulse cranks up the expression of genes that help the plant recognize invading pathogens.
这种脉冲加速了基因的表现，帮助植物识别入侵的病原体。
But, why rain?
然而，为何能识别出雨水呢？
The plant hasn't detected any viruses or bacteria or fungi, just a gentle shower.
植物并未发现有病毒、细菌或真菌的侵扰，仅仅是一场细雨而已。
The researchers emphasize that a lot of plant pathogens can spread by raindrops.
研究人员指出，大量植物病原体的传播是由雨水携带的。
Just like how your mom told you not to go out in the rain or you'll catch a cold, it seems plants gear up whenever it rains to protect themselves from what comes next.
就像妈妈总说的，雨天出门容易着凉，植物在雨中也会采取措施，预防雨后可能带来的各种病菌。
But while that's cool, I promised you “metal”, and now I'm going to deliver.
虽然这很酷，但我曾经保证说它们的手段“强悍”。现在，我要实现我之前的承诺。
The horsenettle plant uses its hairs to tear apart caterpillars from the inside.
马龙葵利用它的绒毛，从内部撕裂毛虫。
These plants have spiky, resilient trichomes that pass through the digestive tracts of caterpillars intact.
这些植物长有坚韧而带刺的细毛，能够不受损伤地通过毛毛虫的消化系统。
What's more, they're wreaking destruction as they go.
此外，它们在穿行过程中也带来了毁灭性的破坏。
In a 2017 paper, researchers documented that the guts of tobacco hornworm caterpillars were being "stretched, punctured, and torn" -- their words!
2017年的一项研究报告中，科学家们描述了烟草角蛾幼虫的内脏如何被“拉扯、穿孔、撕裂”——这是研究者们的表述！
They also showed that caterpillars preferred to avoid diets full of spikes, and it's no wonder why.
研究还发现，这些幼虫倾向于回避那些布满尖刺的食物，这一点也不奇怪。
They even went the extra mile and showed that silverleaf nightshade, a plant with similar trichomes, produced similar results.
他们还不遗余力地进一步证明，银叶茄这种长有类似毛状体的植物也有相似的效果。
But tobacco, which has different trichomes, didn't put them off.
然而，具有不同类型毛状体的烟草，并未使这些幼虫望而却步。
But there's at least one strategy even more brutal than ripping apart a herbivore's guts.
还有一些策略，其残忍性甚至超过了撕碎食草动物内脏的手段。
See, plenty of plants have defensive trichomes like the horsenettle.
实际上，像马龙葵这样拥有防御型毛状体的植物并不少见。
Some of them are specifically referred to as hooked trichomes, and can actually capture insects that encounter them.
它们中的一些特指为勾状毛状体，能够直接捕获接触到它们的昆虫。
And for a while, researchers assumed this was a relatively passive process that would occur when insects walked across or bumped into a trichome.
此外，研究者曾一度认为昆虫被捕捉的过程相对被动，只有在它们在毛状体上爬行或不经意间触碰时才会发生。
But in yet another study from 2017 in the journal Frontiers in Plant Science, one group showed it can be a bit more… personal.
然而，在2017年发表于《植物科学前沿》的另一项研究中，一组科学家展示了这个过程实际上可能更具针对性。
In the paper, they looked at leafminer flies interacting with plain, boring old kidney bean plants.
在这篇论文中，研究人员观察了叶矿蝇与普通无奇的菜豆植物之间的互动。
And… some flies' legs did get trapped, which is about what fly part you'd expect to bump into the trichomes first.
果不其然，一些叶矿蝇的腿被缠绕在了茸毛中，而且通常它们的腿最先接触到这些细毛的部位。
What the researchers saw most often, however, was that flies became impaled when they extended their mouthparts to feed.
然而，研究人员更常见到的是，叶矿蝇在伸出其口器进食时，往往会被尖刺刺穿。
And second most often after that?
紧随其后，第二常见的情况是什么呢？
Well, female flies have an organ called an ovipositor that they use to deposit eggs.
其实，母蝇体内有一种叫做产卵管的器官，用于产卵。
And when a female fly went to lay eggs in the presence of a trichome… Well.
当母蝇在有刺毛的情况下尝试产卵……好吧。
These flies remain trapped until they struggle free, and that… That just can't be comfortable.
这些苍蝇被困住，挣扎着逃脱，这种感觉……绝对不会是什么舒服的体验。
Even if they escape, they're scarred for life.
即便它们最终挣脱了束缚，也难免留下终生的创伤。
On the list of effective predator defenses, I have to rate this one pretty high.
在捕食者防御策略的排行榜上，我认为这个方法应该名列前茅。
And pretty hardcore. So there you have it.
而且这种方式非常给力。这就是它的全部了。
These are only a few examples of what trichomes can do, which just goes to show you that, before we invented "the Rachel", Mother Nature already came up with totally killer hair.
这些仅仅是毛状体能够做到的几个例子，它们足以证明，早在我们发明出那个流行的“瑞秋”发型之前，大自然就已经孕育出了“令人惊叹的毛发”。