which should go some way to providing food security in the world,

為世界糧食安全提供 一定程度的解決之道，

lies in resurrection plants,

秘密在於復甦植物，

pictured here, in an extremely droughted state.

這張圖片顯示它們處在 嚴重乾旱下的狀態。

You might think that these plants look dead,

你們可能會認為 這些植物看起來已經死了，

but they're not.

但並非如此。

Give them water,

給它們水，

and they will resurrect, green up, start growing, in 12 to 48 hours.

它們會在 12 到 48 小時內 復甦、變綠、開始成長。

Now, why would I suggest

為什麼我會說

that producing drought-tolerant crops will go towards providing food security?

培育耐旱作物 可以提供糧食安全？

Well, the current world population is around 7 billion.

目前全世界約有 70 億人口。

And it's estimated that by 2050,

據估計到了 2050 年，

we'll be between 9 and 10 billion people,

我們會有 90 到 100 億人口，

with the bulk of this growth happening in Africa.

大部分的增長會在非洲。

The food and agricultural organizations of the world

世界糧食與農業組織提出，

have suggested that we need a 70 percent increase

依目前的耕作方式， 我們需要 70% 的成長

in current agricultural practice

以滿足此需求。

to meet that demand.

有鑑於植物位於食物鏈的底層，

Given that plants are at the base of the food chain,

此增長必須由植物提供。

most of that's going to have to come from plants.

70 % 這樣的百分比數字，

That percentage of 70 percent

還沒有考慮到 氣候變遷的潛在影響。

does not take into consideration the potential effects of climate change.

這是截自戴研究員 於 2011 年出版的研究報告，

This is taken from a study by Dai published in 2011,

他考慮到

where he took into consideration

所有氣候變遷的潛在影響，

all the potential effects of climate change

並陳述，除了其它影響，

and expressed them -- amongst other things --

因為缺雨或不常下雨， 乾旱情況會加重。

increased aridity due to lack of rain or infrequent rain.

這裡看到的紅色區域

The areas in red shown here,

是直到最近

are areas that until recently

都很成功的農業用地，

have been very successfully used for agriculture,

但無法再使用，因為降雨不足。

but cannot anymore because of lack of rainfall.

圖上這種情況預計 將於 2050 年發生。

This is the situation that's predicted to happen in 2050.

非洲大部分地區， 事實上全球大部分區域，

Much of Africa, in fact, much of the world,

都會有麻煩。

is going to be in trouble.

我們不得不想一些 非常高明的方式來生產糧食。

We're going to have to think of some very smart ways of producing food.

最好是選耐旱作物。

And preferably among them, some drought-tolerant crops.

非洲有另一件事要記得，

The other thing to remember about Africa is

絕大部分的農業都是 看天田（雨養農業）。

that most of their agriculture is rainfed.

在這個世界培育 耐旱作物並不容易。

Now, making drought-tolerant crops is not the easiest thing in the world.

原因是水。

And the reason for this is water.

水是地球生命的要素。

Water is essential to life on this planet.

所有活著、還在代謝的生物，

All living, actively metabolizing organisms,

舉凡微生物或你我，

from microbes to you and I,

主要都由水組成。

are comprised predominately of water.

所有的生命反應都在水中發生。

All life reactions happen in water.

失去一小部分的水 就會導致死亡。

And loss of a small amount of water results in death.

你和我有 65％ 是水，

You and I are 65 percent water --

只要失去 1% 的水就會死亡。

we lose one percent of that, we die.

但是我們能改變行為 以避免這種情況。

But we can make behavioral changes to avoid that.

植物不能。

Plants can't.

它們牢牢釘在地上。

They're stuck in the ground.

所以首先它們比我們 多含一點水，

And so in the first instance they have a little bit more water than us,

大約 95% 都是水，

about 95 percent water,

可以比我們多失去一點水分，

and they can lose a little bit more than us,

從 10% 到約 70% 都可以， 端看是哪種植物，

like 10 to about 70 percent, depending on the species,

但是只能短暫失水。

but for short periods only.

大部分植物都會想辦法 抗拒或避免失水。

Most of them will either try to resist or avoid water loss.

植物抗拒失水最極端的例子 就是多肉植物。

So extreme examples of resistors can be found in succulents.

它們通常很小、很漂亮，

They tend to be small, very attractive,

但是它們為了保住水分， 付出了極大的代價，

but they hold onto their water at such great cost

就是長得奇慢無比。

that they grow extremely slowly.

可以在樹木或灌木中 找到避免失水的例子。

Examples of avoidance of water loss are found in trees and shrubs.

它們札下深根 ，

They send down very deep roots,

佈下地網尋找水源，

mine subterranean water supplies

隨時補注自己，

and just keep flushing it through them at all times,

保持含水狀態。

keeping themselves hydrated.

右邊這種樹 叫波巴布樹（猢猻樹）。

The one on the right is called a baobab.

又稱為倒栽樹，

It's also called the upside-down tree,

就是因為根與莖的比例 差別如此之大，

simply because the proportion of roots to shoots is so great

看起來很像倒著種的樹。

that it looks like the tree has been planted upside down.

當然它的根部 必需讓整棵樹含水。

And of course the roots are required for hydration of that plant.

大概最常見的避免失水策略 可在一年生植物中看到。

And probably the most common strategy of avoidance is found in annuals.

一年生植物 佔糧食供給的一大部分。

Annuals make up the bulk of our plant food supplies.

我國西海岸，

Up the west coast of my country,

一年大部分的時間 都看不到什麼植物生長。

for much of the year you don't see much vegetation growth.

但是春天一下雨， 你就看到這個：

But come the spring rains, you get this:

開花的沙漠。

flowering of the desert.

一年生植物的策略，

The strategy in annuals,

是只在雨季成長。

is to grow only in the rainy season.

到了季末它們會結種子，

At the end of that season they produce a seed,

種子是乾的， 8% 到 10% 的水，

which is dry, eight to 10 percent water,

但是的確是活的。

but very much alive.

那麼乾卻還活著的東西，

And anything that is that dry and still alive,

我們就稱為耐旱。

we call desiccation-tolerant.

在乾燥狀態時，

In the desiccated state,

種子能做的就是 靜躺在極端環境下

what seeds can do is lie in extremes of environment

很長一段時間。

for prolonged periods of time.

下次雨季來時，

The next time the rainy season comes,

就發芽成長，

they germinate and grow,

生命週期周而復始。

and the whole cycle just starts again.

大家普遍認為 種子的耐旱性演化

It's widely believed that the evolution of desiccation-tolerant seeds

可以使開花植物

allowed the colonization and the radiation

或被子植物，能在陸地上拓殖、輻射。

of flowering plants, or angiosperms, onto land.

再來談一年生植物 如何成為最主要的糧食來源。

But back to annuals as our major form of food supplies.

小麥、稻米及玉米 佔植物糧食供應量的 95%。

Wheat, rice and maize form 95 percent of our plant food supplies.

這是很好的策略，

And it's been a great strategy

因為你可以在短時間內 生產大量的種子。

because in a short space of time you can produce a lot of seed.

種子富含能量， 所以能提供很多卡路里，

Seeds are energy-rich so there's a lot of food calories,

你可以儲糧以備飢荒，

you can store it in times of plenty for times of famine,

但是有個缺點。

but there's a downside.

一年生植物的營養組織，

The vegetative tissues,

根部及葉片，

the roots and leaves of annuals,

沒有太多

do not have much

抗受性、迴避性或耐受性的遺傳特質。

by way of inherent resistance, avoidance or tolerance characteristics.

它們不需要這些特質。

They just don't need them.

它們在雨季生長，

They grow in the rainy season

然後結種子以幫助它們 撐過一年其餘的日子。

and they've got a seed to help them survive the rest of the year.

所以儘管在農業界 大家一致努力

And so despite concerted efforts in agriculture

要改良作物的

to make crops with improved properties

抗受性、迴避性及耐受性，

of resistance, avoidance and tolerance --

尤其是抗受性及迴避性，

particularly resistance and avoidance

因為我們有很好的範本 瞭解這些如何作用，

because we've had good models to understand how those work --

我們仍然得到像圖上 這樣的結果。

we still get images like this.

非洲的玉米田

Maize crop in Africa,

在兩星期無雨的情況下，

two weeks without rain

死亡殆盡。

and it's dead.

我們有一個解決方案：

There is a solution:

復甦植物。

resurrection plants.

這種植物可以失去 細胞內 95% 的水分，

These plants can lose 95 percent of their cellular water,

維持在乾燥、近似死亡 狀態下數月到數年，

remain in a dry, dead-like state for months to years,

然後給它們水分，

and give them water,

它們就會變綠，又開始成長。

they green up and start growing again.

這些就像種子一樣 可以耐旱。

Like seeds, these are desiccation-tolerant.

這些就像種子一樣 可以禁得起極端環境條件。

Like seeds, these can withstand extremes of environmental conditions.

這是非常罕見的現象。

And this is a really rare phenomenon.

只有 135 種開花植物 可以做到這點。

There are only 135 flowering plant species that can do this.

我要給大家看一段影片，

I'm going to show you a video

是這三種植物的復甦過程，

of the resurrection process of these three species

按圖片上的順序播放。

in that order.

影片下方有時間軸，

And at the bottom,

大家可以看到過程有多快。

there's a time axis so you can see how quickly it happens.

（掌聲）

(Applause)

很驚人吧？

Pretty amazing, huh?

我過去 21 年都在 試著瞭解它們如何辦到這一點。

So I've spent the last 21 years trying to understand how they do this.

這些植物如何能乾枯卻不死亡？

How do these plants dry without dying?

我研究很多種不同的復甦植物，

And I work on a variety of different resurrection plants,

這裡看到的是含水及乾燥狀態，

shown here in the hydrated and dry states,

有幾個原因。

for a number of reasons.

其中一個是這裡的 每種植物都充作研究範本，

One of them is that each of these plants serves as a model

以研究我想培育的耐旱作物。

for a crop that I'd like to make drought-tolerant.

舉個例子，左上方是一種草，

So on the extreme top left, for example, is a grass,

畫眉草屬植物，

it's called Eragrostis nindensis,

它有個近親叫 衣索比亞畫眉草，

it's got a close relative called Eragrostis tef --

很多人叫它苔麩，

a lot of you might know it as "teff" --

這是衣索比亞國民食物，

it's a staple food in Ethiopia,

無麩質，

it's gluten-free,

我們想讓它耐旱。

and it's something we would like to make drought-tolerant.

另一個原因要看各種植物，

The other reason for looking at a number of plants,

就是，至少起初是這樣，

is that, at least initially,

我想知道：是不是 每種植物都有同樣的反應？

I wanted to find out: do they do the same thing?

是不是都用同一種機制

Do they all use the same mechanisms

讓自己失水卻不至於死？

to be able to lose all that water and not die?

所以我著手用我們稱為 系統生物學的方法，

So I undertook what we call a systems biology approach

以期對耐旱性能有完整的瞭解，

in order to get a comprehensive understanding

我們看所有的東西，

of desiccation tolerance,

從分子到全株、 生理生態學階層都看。

in which we look at everything

舉個例子，我們會看像是

from the molecular to the whole plant, ecophysiological level.

植物在變乾的過程中， 在解剖學上經歷的變化

For example we look at things like

及其超微結構。

changes in the plant anatomy as they dried out

我們會看轉錄組， 這只是一個技術名詞，

and their ultrastructure.

基本上就是要看哪些基因

We look at the transcriptome, which is just a term for a technology

在因應乾燥過程中 會被開啟或關閉。

in which we look at the genes

大部分的基因都製造蛋白質， 所以我們也看蛋白質組。

that are switched on or off, in response to drying.

為了因應乾燥， 會製造出哪些蛋白質？

Most genes will code for proteins, so we look at the proteome.

有些蛋白質是為了合成酵素， 產生代謝物，

What are the proteins made in response to drying?

所以我們也看代謝物組。

Some proteins would code for enzymes which make metabolites,

這很重要， 因為植物牢牢釘在地上。

so we look at the metabolome.

它們用我稱為 非常精準的化學兵工廠

Now, this is important because plants are stuck in the ground.

來保護自己不受環境逆境影響。

They use what I call a highly tuned chemical arsenal

所以去看死亡過程的 化學變化就很重要。

to protect themselves from all the stresses of their environment.

我們最近的研究 在看分子層次，

So it's important that we look

我們看的是脂類組，

at the chemical changes involved in drying.

脂質如何變化以因應死亡。

And at the last study that we do at the molecular level,

這也很重要，

we look at the lipidome --

因為所有的生物膜 都由脂質組成。

the lipid changes in response to drying.

它們能形成薄膜是因為在水中。

And that's also important

把水拿掉，薄膜就會解體。

because all biological membranes are made of lipids.

脂質還作為打開基因的信號。

They're held as membranes because they're in water.

然後我們用生理及生化研究

Take away the water, those membranes fall apart.

試著瞭解我們假設的 保護因子的功用，

Lipids also act as signals to turn on genes.

這些因子是我們 在其它研究中發現的。

Then we use physiological and biochemical studies

然後用所有研究結果 去試著瞭解

to try and understand the function of the putative protectants

植物如何適應自然環境。

that we've actually discovered in our other studies.

我一直有套哲理， 就是我必須

And then use all of that to try and understand

對耐旱性機制有全盤瞭解，

how the plant copes with its natural environment.

才能對其生物應用 提出有意義的建議。

I've always had the philosophy that I needed a comprehensive understanding

我很確信有些人正在想：

of the mechanisms of desiccation tolerance

「生物應用？

in order to make a meaningful suggestion for a biotic application.

她是說她要培育基改作物？」

I'm sure some of you are thinking,

這個問題的答案是：

"By biotic application,

要看你怎麼定義基改。

does she mean she's going to make genetically modified crops?"

我們今天吃的作物， 小麥、稻米、玉米，

And the answer to that question is:

其基因都已改造成 與原來的老祖宗大不相同，

depends on your definition of genetic modification.

但是我們不認為這些是基改，

All of the crops that we eat today, wheat, rice and maize,

因為這些是傳統育種的產物，

are highly genetically modified from their ancestors,

如果你問，我是否要把 復甦作物的基因放進作物中，

but we don't consider them GM

答案是沒錯。

because they're being produced by conventional breeding.

時間就是成敗的關鍵， 我們已經試過這種方法。

If you mean, am I going to put resurrection plant genes into crops,

更正確的說法是 我在開普敦大學的合作夥伴，

your answer is yes.

湯姆森和拉弗丁博士，

In the essence of time, we have tried that approach.

已經帶頭做這種方法，

More appropriately, some of my collaborators at UCT,

我等一下就會 給大家看一些數據。

Jennifer Thomson, Suhail Rafudeen,

但是我們即將用一項 非常有野心的方法，

have spearheaded that approach

我們的目標是打開一系列基因，

and I'm going to show you some data soon.

它們本來就存在於每種作物內。

But we're about to embark upon an extremely ambitious approach,

只是在非常乾旱的情況下 這些基因從未被打開過。

in which we aim to turn on whole suites of genes

我讓大家自己判斷

that are already present in every crop.

這該不該稱為基改。

They're just never turned on under extreme drought conditions.

我現在就給大家看一下 第一次做的數據。

I leave it up to you to decide

為了讓大家明白，

whether those should be called GM or not.

我必須解釋一下 基因如何運作。

I'm going to now just give you some of the data from that first approach.

你們大概都知道

And in order to do that

基因由雙股 DNA 組成。

I have to explain a little bit about how genes work.

DNA 緊密纏繞成染色體，

So you probably all know

存在於你或植物體內的 每一個細胞中。

that genes are made of double-stranded DNA.

如果你把 DNA 解開， 就得到基因。

It's wound very tightly into chromosomes

每個基因都有一個啟動子，

that are present in every cell of your body or in a plant's body.

就像開關一樣，

If you unwind that DNA, you get genes.

還有基因編碼區，

And each gene has a promoter,

及一個終止子，

which is just an on-off switch,

表示這是該基因的終點， 下一個基因要開始。

the gene coding region,

啟動子不像開關 那麼簡單。

and then a terminator,

它們通常需要很多微調，

which indicates that this is the end of this gene, the next gene will start.

很多條件必須存在且正確， 基因才會打開。

Now, promoters are not simple on-off switches.

所以做生技研究時，

They normally require a lot of fine-tuning,

我們通常使用可誘導型啟動子，

lots of things to be present and correct before that gene is switched on.

我們知道如何開啟它。

So what's typically done in biotech studies

我們將其與要研究的基因配對

is that we use an inducible promoter,

並放入植物中， 看該植物如何反應。

we know how to switch it on.

在我要跟大家談的這個研究中，

We couple that to genes of interest

我的合作夥伴用一種 由乾旱誘發的啟動子，

and put that into a plant and see how the plant responds.

我們在復甦植物中發現。

In the study that I'm going to talk to you about,

這個啟動子的好處是 我們不用管它。

my collaborators used a drought-induced promoter,

植物本身會感覺到乾旱。

which we discovered in a resurrection plant.

我們用這個啟動子驅動 復甦植物內的抗氧化基因。

The nice thing about this promoter is that we do nothing.