可爱的松树在前院的草丛上投下了阴凉。如果这时我告诉你这颗松树的根部感染了大量的真菌，你会感到担心吗?如果我告诉你这种真菌是靠吸收根部的糖、维他命以及其它营养物质来生存，你会买来强力除菌剂除掉它们吗?
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.
事实上，大多种类的树木和植物的根部都会感染菌根真菌，但你没有理由惊慌。在今天的科学时刻我们会一同学习树木如何与它们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.
许多树木和植物不仅仅是菌根真菌的宿主——它们实际上是在依靠这些真菌。随着真菌不断的繁衍，大量细长的触须涌向土壤。这些触须会将大量的水分和营养物质引回宿主树木的身边，这远比树木的根部自身所捕获的水分要多。
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.
一个研究发现有真菌的针叶树比没有真菌的针叶树在干旱中幸存的几率高两倍。有些菌根真菌还能在其他方面帮助宿主树木。它们刺激树木的根部分泌激素，以长出新的根须，这种激素也能延长新树根的寿命。
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.
还有一些真菌会在土壤中释放天然的抗生素，进一步保护树木。实际上，如果幼树在第一年的生长期中没有真菌寄生在其根部，那么大量的幼树都会死亡。
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.
生物概念下的共生现象是指两种或者多种不相关联的物种共同进化，互相依存，而树木与真菌就是一个显著的例子。它向我们展示了生命之网的内在联系。生命之网虽然脆弱，但却蕴育了繁茂的地球。
