银杏树守护着青春的秘密喷泉

银杏树守护着青春的秘密喷泉

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

随着人类年龄的增长，我们的身体开始变慢并开始衰老。但银杏却不会发生这种情况。

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.

这并不是一个公平的比较，因为这些活化石和标志性的扇形叶子可以活1000多年。一些最古老的银杏叶化石可以追溯到2亿年前。

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.

研究人员想知道是什么让这些树如此长寿。他们比较了几十棵年龄在15岁到667岁之间的银杏树，看看是什么让它们活得这么久。他们的发现发表在《美国国家科学院院刊》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."

“在人类中，随着年龄的增长，我们的免疫系统开始变得不那么好，”该研究的合著者、北德克萨斯大学的生物学家理查德·迪克森告诉《纽约时报》。但在某种程度上，“这些树的免疫系统，即使已经有1000年的历史，看起来也像一个20岁的人。”

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.

研究人员从这些树中提取了薄芯(这对它们没有伤害)来检测它们的年轮。他们特别研究了血管形成层，即树皮下每年生长的一层薄薄的细胞。

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.

他们发现银杏叶中基因表达的衰老——生物衰老和退化——是可以预测的。树叶生长，它们掉下来，然后新的又长出来。但幼龄树和极老树的形成层没有这种差异。

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

这表明，尽管树叶可能会枯死，但根据研究结果，树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.

研究人员说，大多数树木似乎死于害虫或干旱等压力因素。

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."

巴塞罗那大学的植物生理学家Sergi Munne-Bosch告诉《科学》杂志，不需要担心变老是“人类很难理解的事情”。“老化对这个物种来说不是问题，”他说。“他们必须应对的最重要的问题是压力。”

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

研究人员认为，对类似的长寿树种，如红杉和英国紫杉的研究也会得出类似的结果。

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

阿伯里斯特威斯大学的植物生物学家霍华德·托马斯告诉《科学》杂志:“植物的默认条件是不朽。”