The corpse flower may keep you up at night - Daniel Nickrent

譯者: Lilian Chiu 審譯者: Amanda Zhu

Deep inside the Sumatran rainforest, a carrion fly descends,

在蘇門答臘雨林的深處， 有一隻麗蠅向下飛去，

guided by the scent of its favorite place to lay eggs:

吸引牠的是牠最愛的 產卵地點所散發的氣味：

dead and rotting animal carcasses.

死動物的腐屍味。

But when it lands, it isn’t on liquefying flesh,

但牠降落時，卻沒有發現腐敗的肉，

but instead on the world’s biggest, and perhaps strangest, flower—

反而是降落在世界上最大 且可能最奇怪的花上——

Rafflesia arnoldii.

阿諾爾特大花草。

Rafflesia is a genus of over 30 species

大花草屬的物種有超過三十種，

found across the tropical forests of Southeast Asia.

在東南亞的熱帶森林 各處都可以找到。

While its smallest representative has a flower only a few centimeters wide,

最小的大花草花朵只有幾公分寬，

its biggest weighs seven kilograms and spans over a meter wide.

但最大的花朵重達七公斤， 寬度超過一公尺。

And its putrid aroma isn’t the only thing that sets these plants apart—

這些植物與眾不同之處 不只是腐敗的氣味——

all Rafflesia are parasites.

所有的大花草都是寄生性植物。

For most of its life, the Rafflesia plant exists as an endophyte,

大花草植物一生中大部分的時期 都以內部寄生植物的形式存在，

a single thin strand of almost uniform cells beneath the bark of its host.

是由幾乎一致的細胞 形成的細長條狀，

位在宿主的樹皮下。

It strictly infects Tetrastigma,

它只會感染崖爬藤屬，

a genus of large vines related to the grape.

和葡萄有親屬關係的大型藤蔓屬。

Like typical leafy plants, the host Tetrastigma’s cells contain chloroplasts.

和典型的多葉植物一樣，

崖爬藤屬宿主的細胞內有葉綠體。

These organelles convert sunlight into energy

這些細胞器會將陽光轉換為能量，

and are each equipped with their own DNA.

且每個細胞器都有自己的 DNA。

Rafflesia’s plastids, on the other hand, appear to have lost their DNA,

另一方面，大花草的色素體 顯然在演化中失去了 DNA。

and with it the ability to photosynthesize.

也一併失去行光合作用的能力。

This sort of loss is incredibly rare.

這種缺陷非常罕見。

With no roots and no ability to produce its own food,

沒有根，也沒有能力 為自己製造食物，

Rafflesia is completely dependent on its host,

大花草完全要依賴它的宿主，

siphoning the Tetrastigma’s water and nutrients to fuel its own growth.

抽取崖爬藤的水份和營養，

供自己成長使用。

And Rafflesia’s propensity for theft doesn’t end there.

且大花草的偷竊習慣還不只如此。

Using a process known as horizontal gene transfer, or HGT,

使用一種叫做水平基因 轉移（HGT）的作用，

Rafflesia has stolen quite a bit of genetic material from its host

大花草從它的宿主 及生長地的其他植物身上，

and other plants in its habitat.

偷了相當不少基因物質。

While HGT is well known in bacteria,

細菌的 HGT 已經廣為人知，

it has only recently been documented in parasitic plants.

但直到最近才有關於 寄生植物 HGT 的記錄。

And scientists are still trying to understand

且科學家仍然在試圖了解

exactly how this DNA transfer happens.

這種 DNA 轉移是怎麼發生的。

Rafflesia appears to utilize several of these stolen sequences

大花草很顯然可以

把許多偷來的基因序列 當成自己的來使用，

as if they were their own,

transcribing the DNA into RNA and then translating it into proteins,

將 DNA 轉錄為 RNA，

再將之翻譯為蛋白質，

which are used in key cellular processes.

然後用在關鍵的細胞活動中。

After living some time embedded in the host vine,

在宿主的藤蔓內部 生存了一段時間後，

Rafflesia emerges as a single bud,

大花草會以單一花蕾的形式出現。

which then takes several months, or even a year, to reach full size.

需要數個月，甚至一年， 花蕾才會長到完整的尺寸。

When it opens, its fleshy maroon petals

當它打開時，它的紅褐色的肉質花瓣

emit several foul-smelling sulfur-containing compounds.

會散發出數種很難聞的含硫化合物。

The evolutionary reason for this odor is relatively straightforward:

散發這種氣味的演化理由就相當直接：

to attract pollinators.

吸引傳粉昆蟲。

For most species of Rafflesia, single flowers are either male or female.

就大部分的大花草物種而言，

單一朵花若不是雄性就是雌性。

So, to produce a seed,

因此，若要產生種子，

pollen must be transferred from one flower to the next.

必須要把花粉從一朵花 轉移到另一朵花。

The rotten stench is ideal for attracting corpse-loving carrion flies,

腐爛的惡臭非常能夠 吸引喜愛屍體的麗蠅，

and the massive size of the flower may help broadcast it

且超大型的花朵可能可以協助

在不流動的雨林空氣中 將氣味傳播出去。

through the stagnant rainforest air.

A deceived fly will explore the flower’s interior,

受騙的麗蠅會去探索花朵的內部，

laying thousands of ill-fated eggs.

產下數千個不幸的卵。

But during the fly’s visit,

但在麗蠅造訪時，

the male Rafflesia’s liquid pollen may end up on the fly’s back where it dries.

雄性大花草的液態花粉

可能會落在麗蠅背上，在那裡乾掉。

If the fly encounters an open female Rafflesia flower,

如果麗蠅再到綻開的 雌性大花草花朵，

the pollen will rehydrate when rubbed against the flower’s damp stigma,

當花粉與花朵的潮濕柱頭 磨擦時，會重新吸濕，

completing cross-pollination.

完成異花傳粉。

A pollinated Rafflesia flower gradually withers and turns black,

被授粉的大花草花朵 會漸漸枯萎、變黑，

but this doesn't mean it's dead.

但這不表示它死了。

Over several months, a fruit forms which contains thousands of tiny seeds.

在幾個月內，會有一顆果實形成，

內有數千顆小種子。

But what disperses these seeds is still debated,

是誰來散播這些種子，還沒有定論，

with hypotheses ranging from elephants to rodents to ants.

從大象，到齧齒目動物， 到螞蟻等假設都有。

We do know that the seeds have an oily appendage called an elaiosome,

我們確實知道的是，這些種子 有一種油狀的附屬構造，

叫做油質體，

a structure ants often feed to their larvae.

螞蟻通常會拿油質體 去餵食牠們的幼蟲。

And scientists have even observed ants carrying Rafflesia seeds.

科學家甚至已經觀察到 有螞蟻帶著大花草的種子。

But what happens to the Rafflesia seeds once inside the ant nest remains unclear.

但大花草的種子被帶到 螞蟻窩裡面之後會發生什麼事

仍然是未知。

In any case, nobody has seen Rafflesia seeds germinate,

無論如何，都沒有人 看過大花草的種子

or attach to and infect a host root.

在宿主的根部發芽、附著、生長。

Because this crucial step of their development is still not fully understood,

因為尚未完全了解這個關鍵步驟，

cultivation of Rafflesia is difficult.

栽培大花草仍然有困難。

Despite many attempts, botanists from around the globe

儘管世界各地的植物學家多次嘗試

have been largely unsuccessful at growing Rafflesia

在大花草的天然生長地以外的地方

from seeds outside its natural habitat.

從種子培養出大花草的試驗 大多未能成功。

As these tropical forests are under threat,

現在這些熱帶森林受到威脅，

we’re at risk of losing Rafflesia,

我們有可能會失去大花草，

and our ability to unravel some of its many remaining secrets.

也會失去解開大花草之謎的機會。