Rising CO2 Pushes Plants to Drink Sparingly

好事儿还是坏事儿?空气中二氧化碳的含量升高让植物用水效率更高
时间:2018-01-12 单词数:3930

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导读:研究表明,随着空气中二氧化碳含量的不断升高,植物的用水效率得到了提升,可能成为缓解干旱的新方法。

植物用水效率_Scientific American新闻

The Mauna Loa Observatory sits on the side of a Hawaiian volcano, 11,000 feet above the Pacific. And for nearly 60 years, an instrument there has been sniffing the local air—taking a census of carbon dioxide molecules. In that time, CO2 levels have steadily risen, from about 315 parts per million, to 405. And plants enjoy the extra carbon.

莫纳罗亚天文台坐落在夏威夷一座火山边上,位于太平洋上空1.1万英尺。近60年来,该天文台的一台仪器一直在监测当地空气,计算二氧化碳分子的数量。在这段时间,二氧化碳水平稳步上升,含量从百万分之三百一十五上升至百万分之四百零五。植物很享受这种额外的碳含量。

"It’s kinda obvious plants are gonna react to CO2 in the atmosphere, because it changes the environment which they (the leaves) are bathed in." Ralph Keeling, a geochemist at the Scripps Institution of Oceanography. "And it’s very hard for the plants not to benefit from that by having a higher water-use efficiency. But what wasn’t clear was how much more efficient they were gonna be."

“很明显植物会与空气中的二氧化碳产生反应,因为二氧化碳改变了叶子所处的环境。”斯克里普斯海洋研究所的地球化学家拉尔夫·基林说道。“拥有更高的用水效率,植物很难不从中受益。但并不清楚效率会增加多少。”

So what’s water-use efficiency? Like us, plants need water for basic life processes. And they open tiny pores in their leaves to allow carbon dioxide in for photosynthesis. But the holes also let the precious water out. Higher water-use efficiency just means losing less water while taking in the CO2.

那什么是用水效率?和我们人类一样,植物也需要水来维持基本生命过程。植物打开叶子中的微小气孔,让二氧化碳进入体内,参与光合作用。而气孔也会让宝贵的水分流失。用水效率提高意味着植物在吸收二氧化碳时流失的水分会减少。

To figure out that just how much the efficiency improves, Keeling and his team examined the ratio of CO2 having the isotope carbon 13 versus its lighter and much more prevalent cousin, carbon 12. "So the ratio is 0.2 percent lower than it was pre-industrially. Doesn’t sound like a lot, does it?"

为了算出用水效率的改善程度,基林和团队检测了二氧化碳中同位素碳-13与比它更轻更普遍的同位素碳-12的比率。“现在的比率比前工业化时代低0.2%。听起来并没有差太多,是吧?”

And yet, that small change in carbon 13 versus carbon 12 allowed Keeling and his colleagues to quantify just how much more efficiently plants are sipping water in a higher-CO2 regime. And, it turns out, their water use efficiency rises right in step with CO2 levels.

但是,碳-13与碳-12比率的微小改变,却可以让基林和同事对植物在二氧化碳含量更高时期吸水效率所增加的数额进行量化。结果显示,植物的用水效率的确随二氧化碳含量一起上升了。

"If you dial back to how much CO2 has gone up since preindustrial times, you’re talking about something like 40 percent increase in CO2 overall, and thus a 40 percent increase in some measure of water-use efficiency. So it’s no small change." The study is in the Proceedings of the National Academy of Sciences.

“如果再来算算从前工业化时代至今二氧化碳的增加量,你会发现二氧化碳总体增加了约40%,所以用水效率在某种程度上也增加了40%。因此,这可是不小的变化。”这项研究结果发表在《美国科学院院报》上。

As we flood the atmosphere with more CO2, and average global temperatures rise, some areas of the planet are getting wetter. But other spots face a drier future—where this water-sipping innovation might be a lifesaver. Unfortunately, there’s no evidence that in a hotter future, we humans will naturally use water more efficiently, too.

我们向空气中排放的二氧化碳量越来越多,全球平均温度也随之上升,而地球上的某些地区会变得更加潮湿。但未来其他地区会越来越干旱,这种吸水创新法在那些地区也许会成为救星。不幸的是,现在并没有证据证明在愈发炎热的未来,人类也会自然而然地提高用水效率。

来源:Scientific American爱语吧作者:kang919000

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