Scientists discover how plants breathe -- and how humans shaped their 'lungs'

科学家们发现了植物呼吸的方式以及人类如何塑造植物的“肺”

上海译锐翻译  2019-7-1   13:57 p.m.

© constantincornel / Adobe Stock

Scientists have discovered how plants create networks of air channels -- the lungs of the leaf -- to transport carbon dioxide (CO2) to their cells.

科学家们发现了植物是如何形成空气通道网（叶子的肺部）并将二氧化碳传送至细胞的。

Botanists have known since the 19th century that leaves have pores -- called stomata -- and contain an intricate internal network of air channels. But until now it wasn't understood how those channels form in the right places in order to provide a steady flow of CO2 to every plant cell.

自19世纪以来，植物学家们就发现叶子有一种被称为“气孔”的小孔并有一个复杂的内部空气通道网。但是，直到现在，植物学家们才弄明白，这些通道是如何在恰当的地方形成并为每一个细胞稳定输送二氧化碳的。

The new study, led by scientists at the University of Sheffield's Institute for Sustainable Food and published in Nature Communications, used genetic manipulation techniques to reveal that the more stomata a leaf has, the more airspace it forms. The channels act like bronchioles -- the tiny passages that carry air to the exchange surfaces of human and animal lungs.

由谢菲尔德大学绿色食物学院科学家们所牵头的新研究（研究论文发表于《自然通信》）运用基因操控技术表明，一片树叶所拥有的气孔越多，它所形成的空气空间也就越大。类似于细支气管的通道-微小管道会将空气带到人们和动物肺部的交换表面。

In collaboration with colleagues at the University of Nottingham and Lancaster University, they showed that the movement of CO2through the pores most likely determines the shape and scale of the air channel network.

在与诺丁汉大学和兰卡斯特大学同事合作的过程中，科学家们发现，二氧化碳穿过气孔的过程极有可能决定了空气通道网的形状和规模。

The discovery marks a major step forward in our understanding of the internal structure of a leaf, and how the function of tissues can influence how they develop -- which could have ramifications beyond plant biology, in fields such as evolutionary biology.

这一发现使我们在了解树叶内部结构方面以及细胞的功能如何对细胞的发展发挥作用（可能具有植物生物学之外的衍生影响，比如进化生物学方面）又迈进了一大步。

The study also shows that wheat plants have been bred by generations of people to have fewer pores on their leaves and fewer air channels, which makes their leaves more dense and allows them to be grown with less water.

研究还发现，在数代人的培育下，小麦叶子表面的气孔和空气通道都越来越少，这也造成了小麦的叶子更加浓密并可以在水更少的情况下生长。

This new insight highlights the potential for scientists to make staple crops like wheat even more water-efficient by altering the internal structure of their leaves. This approach is being pioneered by other scientists at the Institute for Sustainable Food, who have developed climate-ready rice and wheat which can survive extreme drought conditions.

这一新发现让科学家可以进一步通过改变树叶内部结构的方式让小麦等主要粮食作物更加节水。绿色食物学院的其他科学家们已经率先开始采用这一方法来研发出能够适应气候并且能够抵御极端干旱条件的水稻和小麦。

Professor Andrew Fleming from the Institute for Sustainable Food at the University of Sheffield said: "Until now, the way plants form their intricate patterns of air channels has remained surprisingly mysterious to plant scientists.

来自谢菲尔德绿色食物学院的Andrew Fleming教授表示：“直到现在，植物形成复杂的空气通道的方式对于植物科学家们而言仍然属于未知领域。”

"This major discovery shows that the movement of air through leaves shapes their internal workings -- which has implications for the way we think about evolution in plants.

“这一重大发现表明，空气穿过树叶的运动方式决定了树叶的内部工作方式-而这对于我们思考植物进化的方式也具有影响。”

"The fact that humans have already inadvertently influenced the way plants breathe by breeding wheat that uses less water suggests we could target these air channel networks to develop crops that can survive the more extreme droughts we expect to see with climate breakdown."

“人们无意中通过利用更少的水来栽培小麦的方式已经对植物呼吸的方式产生了影响，这意味着我们可以针对这些空气通道网来培育可以应对极端干旱气候的作物。”

Dr Marjorie Lundgren, Leverhulme Early Career Fellow at Lancaster University, said: "Scientists have suspected for a long time that the development of stomata and the development of air spaces within a leaf are coordinated. However, we weren't really sure which drove the other. So this started as a 'what came first, the chicken or the egg?' question.

兰卡斯特大学Leverhulme青年研究学者-Marjorie Lundgren博士表示：“科学家们早已怀疑，气孔的发展和叶片中空气层间的发展是相互协调的。然而，我们确实不太肯定哪个先，哪个后。所以，这也提出了‘是鸡生蛋，还是蛋生鸡？’的问题。”

"Using a clever set of experiments involving X-ray CT image analyses, our collaborative team answered these questions using species with very different leaf structures. While we show that the development of stomata initiates the expansion of air spaces, we took it one step further to show that the stomata actually need to be exchanging gases in order for the air spaces to expand. This paints a much more interesting story, linked to physiology."

通过采取各种实验组合，我们的合作团队利用X光线CT成像分析和各种不同种类的树叶结构回答了这些问题。我们发现，气孔的发展推动了空气空间的扩大。随之，我们进一步发现，气孔实际需要交换气体，以确保空气空间不断扩大。这就形成了一个更加有趣的、与生理机能有关的故事。

The X-ray imaging work was undertaken at the Hounsfield Facility at the University of Nottingham. The Director of the Facility, Professor Sacha Mooney, said: "Until recently the application of X-ray CT, or CAT scanning, in plant sciences has mainly been focused on visualising the hidden half of the plant -- the roots -- as they grow in soil.

X光成像工作在诺丁汉大学的Hounsfield工作室展开。工作室主任，Sacha Mooney教授表示：“直到最近，X光线CT或CAT扫描在植物学科中的应用重点是将植物隐藏的另一半，即根系显现出来。”

"Working with our partners in Sheffield we have now developed the technique to visualise the cellular structure of a plant leaf in 3D -- allowing us to see how the complex network of air spaces inside the leaf controls its behaviour. It's very exciting."

“通过与谢菲尔德的同仁共同合作，我们现在已经研发出一种可以将植物叶片中的细胞结构进行3D视觉化的技术。这一技术可以使我们发现叶片内部复杂的空气空间网如何影响叶片的行为。这是非常令人兴奋的。”

The Institute for Sustainable Food at the University of Sheffield brings together multidisciplinary expertise and world-class research facilities to help achieve food security and protect the natural resources we all depend on.

谢菲尔德大学绿色植物学院汇集了各学科的专业知识和世界领先的研究设备来确保食物的安全性并保护我们所赖以生存的自然资源。

需要了解的词：

Stomata：气孔

Genetic manipulation technique：基因操纵技术

Bronchiole：细支气管

staple crop：主要粮食作物

climate-ready：能够应对气候变化的

Early Career Fellow：青年研究学者

文章来源：科学日报    编辑：Susan