時差N小時:樹根及其真菌好友

If I told you there was a large mass of fungusinfecting the roots of that lovely pine tree whichshades your front lawn, would you be worried?Would you buy a strong fungicide if I said that thisfungus survived by sucking valuable sugars,vitamins, and other nutrients out of your tree'sroots?

可愛的松樹在前院的草叢上投下了陰涼。如果這時我告訴你這顆松樹的根部感染了大量的真菌，你會感到擔心嗎?如果我告訴你這種真菌是靠吸收根部的糖、維他命以及其它營養(yǎng)物質來生存，你會買來強力除菌劑除掉它們嗎?

Actually, most species of tree and plant are routinely infected by what's known as “mycorrhizalfungi,” but this is no cause for alarm. We'll learn how trees can actually benefit from theirfungal friends on today's moment of science.

事實上，大多種類的樹木和植物的根部都會感染菌根真菌，但你沒有理由驚慌。在今天的科學時刻我們會一同學習樹木如何與它們的真菌朋友相互依存，互惠互利。

Many trees and plants not only host mycorrhizal fungi–they have actually come to depend onthem. As the fungi grow, they send fine tentacles streaming into the soil. These tentacles helpchannel large amounts of water and nutrients back to the host tree, far more water than thetree would be able to trap with its roots alone.

許多樹木和植物不僅僅是菌根真菌的宿主——它們實際上是在依靠這些真菌。隨著真菌不斷的繁衍，大量細長的觸須涌向土壤。這些觸須會將大量的水分和營養(yǎng)物質引回宿主樹木的身邊，這遠比樹木的根部自身所捕獲的水分要多。

One study found that conifers with the fungus are twice as likely to survive a drought asthose without. Some mycorrhizal fungi help their host tree in other ways too, secreting a treehormone that causes the roots to grow new root tips, and a hormone that increases thelongevity of these new roots.

一個研究發(fā)現(xiàn)有真菌的針葉樹比沒有真菌的針葉樹在干旱中幸存的幾率高兩倍。有些菌根真菌還能在其他方面幫助宿主樹木。它們刺激樹木的根部分泌激素，以長出新的根須，這種激素也能延長新樹根的壽命。

Other fungi release natural antibiotics into the soil, further protecting the tree. In fact, theseedlings of many tree species will die if fungus does not develop around their roots duringtheir first year of growth.

還有一些真菌會在土壤中釋放天然的抗生素，進一步保護樹木。實際上，如果幼樹在第一年的生長期中沒有真菌寄生在其根部，那么大量的幼樹都會死亡。

This is a striking example of the biological concept of symbiosis, in which two or moreunrelated species have co-evolved and now depend on each other for survival. It shows us justhow interconnected the delicate web of life is. Which covers our planting earth.

生物概念下的共生現(xiàn)象是指兩種或者多種不相關聯(lián)的物種共同進化，互相依存，而樹木與真菌就是一個顯著的例子。它向我們展示了生命之網(wǎng)的內在聯(lián)系。生命之網(wǎng)雖然脆弱，但卻蘊育了繁茂的地球。