銀杏樹(shù)守護(hù)著青春的秘密?chē)娙?/h1>

所屬教程:英語(yǔ)漫讀

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2020年01月15日

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As humans age, our bodies start to slow down and get creaky. But the same doesn't happen with the ginkgo biloba tree.

隨著人類(lèi)年齡的增長(zhǎng)，我們的身體開(kāi)始變慢并開(kāi)始衰老。但銀杏卻不會(huì)發(fā)生這種情況。

It's hardly a fair comparison, as these living fossils with the iconic fan-shaped leaves can live more than 1,000 years. Some of the oldest fossilized ginkgo leaves date back to 200 million years ago.

這并不是一個(gè)公平的比較，因?yàn)檫@些活化石和標(biāo)志性的扇形葉子可以活1000多年。一些最古老的銀杏葉化石可以追溯到2億年前。

Photo: jessicahyde/Shutterstock

Researchers wanted to know what gives these trees their longevity. They compared dozens of ginkgo trees ranging in age from 15 to 667 years old to see what helped them live so long. Their findings were published in the Proceedings of the National Academies of Science.

研究人員想知道是什么讓這些樹(shù)如此長(zhǎng)壽。他們比較了幾十棵年齡在15歲到667歲之間的銀杏樹(shù)，看看是什么讓它們活得這么久。他們的發(fā)現(xiàn)發(fā)表在《美國(guó)國(guó)家科學(xué)院院刊》上。

"In humans, as we age, our immune system begins to start to not be so good," study coauthor Richard Dixon, a biologist at the University of North Texas, told The New York Times. But in a way, "the immune system in these trees, even though they're 1,000 years old, looks like that of a 20-year-old."

“在人類(lèi)中，隨著年齡的增長(zhǎng)，我們的免疫系統(tǒng)開(kāi)始變得不那么好，”該研究的合著者、北德克薩斯大學(xué)的生物學(xué)家理查德·迪克森告訴《紐約時(shí)報(bào)》。但在某種程度上，“這些樹(shù)的免疫系統(tǒng)，即使已經(jīng)有1000年的歷史，看起來(lái)也像一個(gè)20歲的人。”

The ginkgo biloba has distinctive, fan-shaped leaves that also explain its other name: maidenhair tree. (Photo: James St. John [CC BY 2.0]/Flickr)

Researchers took thin cores from the trees (which didn't harm them) to examine their growth rings. They particularly studied the vascular cambium, a thin layer of cells underneath the bark that grows each year.

研究人員從這些樹(shù)中提取了薄芯(這對(duì)它們沒(méi)有傷害)來(lái)檢測(cè)它們的年輪。他們特別研究了血管形成層，即樹(shù)皮下每年生長(zhǎng)的一層薄薄的細(xì)胞。

They found that senescence — biological aging and deterioration — was predictable in the expression of genes in the ginkgo's leaves. Leaves grow, they fall off, then new ones grow again. But there was no such difference in the cambium between very young and very old trees.

他們發(fā)現(xiàn)銀杏葉中基因表達(dá)的衰老——生物衰老和退化——是可以預(yù)測(cè)的。樹(shù)葉生長(zhǎng)，它們掉下來(lái)，然后新的又長(zhǎng)出來(lái)。但幼齡樹(shù)和極老樹(shù)的形成層沒(méi)有這種差異。

This suggests that although leaves might die, the trees themselves are unlikely to ever die of old age, according to the findings.

這表明，盡管樹(shù)葉可能會(huì)枯死，但根據(jù)研究結(jié)果，樹(shù)木本身不太可能死于衰老。

Most trees instead appear to die from stressors such as pests or droughts, the researchers said.

研究人員說(shuō)，大多數(shù)樹(shù)木似乎死于害蟲(chóng)或干旱等壓力因素。

Not needing to be concerned about growing old is "something that for humans is difficult to understand," plant physiologist Sergi Munné-Bosch of the University of Barcelona, told Science. "Aging is not a problem for this species," he says. "The most important problem that they have to deal with is stress."

巴塞羅那大學(xué)的植物生理學(xué)家Sergi Munne-Bosch告訴《科學(xué)》雜志，不需要擔(dān)心變老是“人類(lèi)很難理解的事情”。“老化對(duì)這個(gè)物種來(lái)說(shuō)不是問(wèn)題，”他說(shuō)。“他們必須應(yīng)對(duì)的最重要的問(wèn)題是壓力。”

Researchers believe that studies on similar long-lived trees like redwoods and English yews would yield similar results.

研究人員認(rèn)為，對(duì)類(lèi)似的長(zhǎng)壽樹(shù)種，如紅杉和英國(guó)紫杉的研究也會(huì)得出類(lèi)似的結(jié)果。

Howard Thomas, plant biologist from Aberystwyth University, tells Science: "The default condition in plants is immortality."

阿伯里斯特威斯大學(xué)的植物生物學(xué)家霍華德·托馬斯告訴《科學(xué)》雜志:“植物的默認(rèn)條件是不朽。”