Name: 【TED-Ed】自然驚奇解密：植物的自我防衛機制 (The amazing ways plants defend themselves - Valentin Hammoudi)
Uploaded: 2020-09-05T21:01:30.000Z
Duration: 6 min 12 s

This is a tomato plant, and this is an aphid slowly killing the tomato plant by sucking the juice out of its leaves.

這是棵番茄樹，而這是隻蚜蟲，它不斷吸食樹葉上的汁液，以緩慢的速度殘害番茄樹。

The tomato is putting up a fight using both physical and chemical defenses to repel the attacking insects.

番茄樹正用物理和化學的防禦機制抵抗並驅逐害蟲。

The tomato is also releasing compounds that signal nearby tomato plants to release their own insect repellent.

番茄樹也同時釋放化合物，警告鄰近的番茄樹釋放它們的驅蟲劑。

They face threats ranging from microscopic fungi and bacteria.

它們面臨的威脅有渺小的真菌及細菌、

Small herbivores, like aphids, caterpillars, and grasshoppers.

小型食草昆蟲例如：蚜蟲、毛毛蟲和蚱蜢。

Up to large herbivores, like tortoises, koalas, and elephants.

甚至是大型食草昆蟲例如：陸龜、無尾熊和大象。

All are looking to devour plants to access the plentiful nutrients and water in their leaves, stems, fruits, and seeds.

它們都想吞噬植物，從植物的葉、莖、果實和種子中吸收充足的養分和水分。

But plants are ready with a whole series of internal and external defenses that make them a much less appealing meal, or even a deadly one.

然而植物本身具備的整套內外防禦機制，不僅讓它們變得沒有那麼可口，甚至在食用後還可能致命。

植物的防禦機制從外面的表層開始。

The bark covering tree trunks is full of lignin, a rigid web of compounds that's tough to chew and highly impermeable to pathogens.

樹幹上的樹皮有豐富的木質素，木質素是由難以咀嚼且極有效防止病原體滲透的聚合物組成。

Leaves are protected by a waxy cuticle that deters insects and microbes.

樹葉受到蠟狀角質層保護，以抵禦昆蟲及微生物的侵擾。

Some plants go a step further with painful structures to warn would-be predators.

某些植物採取更強硬的方式，用尖銳的外表警告潛在的掠食者。

Thorns, spines, and prickles discourage bigger herbivores.

荊棘、樹刺和細刺阻礙了大型食草動物。

To deal with smaller pests, some plants' leaves have sharp hair-like structures called trichomes.

為了應付體型較小的害蟲，某些植物葉片演化出毛髮般的結構，稱為毛狀體。

The kidney bean plant sports tiny hooks to stab the feet of bed bugs and other insects.

腰豆樹用細小的鉤刺穿蟲虱以及其他昆蟲的腳。

In some species, trichomes also dispense chemical irritants.

某些種類的植物，毛狀體會釋放化學刺激物質。

Stinging nettles release a mixture of histamine and other toxins that cause pain and inflammation when touched.

蕁麻在被觸摸時會釋放組織胺和其他毒素的混合體，進而造成發炎疼痛反應。

For other plant species, the pain comes after an herbivore's first bite.

而其他種類的植物所引起的疼痛，則會在草食性動物咬下第一口後才會發生。

Spinach, kiwi fruit, pineapple, fuchsia, and rhubarb all produce microscopic needle-shaped crystals called raphides.

菠菜、奇異果、鳳梨、吊鐘花以及大黃，都能製造出稱作「針晶體」的微小針狀結晶物。

They can cause tiny wounds in the inside of animals' mouths, which create entry points for toxins.

針晶體會在動物的口腔內造成數個小傷口，形成毒素的入口。

The mimosa plant has a strategy designed to prevent herbivores from taking a bite at all.

含羞草有保護機制，能夠避免草食性動物的任何食用行為。

Specialized mechanoreceptor cells detect touch and shoot an electrical signal through the leaflet to its base causing cells there to release charged particles.

專門的刺激感受細胞一旦偵測到外部觸碰，就會透過葉子傳輸電子訊號至根部，使細胞釋放帶電粒子。

The buildup of charge draws water out of these cells and they shrivel, pulling the leaflet closed.

電荷的增加使水分排出細胞，細胞萎縮後使葉片蜷縮捲起。

The folding movement scares insects away and the shrunken leaves look less appealing to larger animals.

蜷縮的動作會嚇走昆蟲，大型動物也比較不受萎縮的葉面所吸引。

If these external defenses are breached, the plant immune system springs into action.

若外部防禦機制被攻破，植物的免疫系統就會啟動。

Plants don't have a separate immune system like animals.

植物不像動物一樣有獨立的免疫系統。

Instead, every cell has the ability to detect and defend against invaders.

取而代之的是，每個細胞都有能力偵測和抵禦入侵者。

Specialized receptors can recognize molecules that signal the presence of dangerous microbes or insects.

特殊的受體可以辨識出分子，這個分子是危險的微生物或昆蟲出沒時所發出的信號。

In response, the immune system initiates a battery of defensive maneuvers.

為了回應危險，免疫系統會啟動一系列的防禦機制。

To prevent more pathogens from making their way inside, the waxy cuticle thickens and cell walls get stronger.

為了防止更多病原體入侵，蠟質角質層會變厚且細胞壁會變得更堅固。

And if microbes are devouring one section of the plant, those cells can self-destruct to quarantine the infection.

如果微生物正在吞噬植物的任一部分，植物的細胞會自我毀滅以隔離感染。

Compounds toxic to microbes and insects are also produced, often tailor-made for a specific threat.

同時也會製造對微生物和昆蟲有毒的化合物，通常是針對性地抵禦外部威脅。

Many of the plant molecules that humans have adopted as drugs, medicines, and seasonings evolved as part of plants' immune systems because they're antimicrobial, or insecticidal.

許多人類用來製作藥品、醫療藥劑和調味料的植物分子，因為具有抗菌或殺菌的作用，而演化為植物免疫系統的一部分。

An area of a plant under attack can alert other regions using hormones, airborne compounds, or even electrical signals.

植物的某個部位受到攻擊時，可以用賀爾蒙、空氣中的化合物或甚至是電信號，向其他部位發出警報。

When other parts of the plant detect these signals, they ramp up production of defensive compounds.

植物的其他部分感應到這些信號時，會加速製造防禦性化合物。

And for some species, like tomatoes, this early warning system also alerts their neighbors.

而其他物種如番茄，這種預警系統也會向它們的鄰居發出警報。

Some plants can even recruit allies to adopt a strong offense against their would-be attackers.

有些植物甚至可以結成盟友，對潛在的入侵者發動強大的攻擊。

Cotton plants under siege by caterpillars release a specific cocktail of 10 to 12 chemicals into the air.

被毛毛蟲攻擊的棉花會釋放 10 到 12 種化學混合物質至空中。

This mixture attracts parasitic wasps that lay eggs inside the caterpillars.

這種混合物會吸引在毛毛蟲體內產卵的寄生黃蜂。

Plants may not be able to flee the scene of an attack, or fight off predators with teeth and claws, but with sturdy armor, a well-stocked chemical arsenal, a neighborhood watch, and cross-species alliances, a plant isn't always an easy meal.

植物可能無法逃離突擊現場，也無法用牙齒和爪子擊退掠食者，但憑藉堅固的鎧甲、儲備充足的化學武器、鄰里的守望相助和跨物種聯盟，享受植物大餐可沒那麼容易！

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【TED-Ed】自然驚奇解密：植物的自我防衛機制 (The amazing ways plants defend themselves - Valentin Hammoudi)

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