土壤里的水分被树的根部吸收，沿着树的管道系统旅行，先经过长长的树干，再到细细的树枝，最后进入到树叶微小的导管里。为什么大树能够克服地球的引力，每天将数升的水输送到高高的树梢上去？迄今为止，生学家还说不清这到底是怎么回事。“树木中水的输送听起来好像是很自然 The moisture in the soil is absorbed by the roots of the tree and travels along the pipe system of the tree, passing through the long trunks, to the thin branches, and finally into the tiny tubes of the leaves. Why does the tree overcome the gravity of the earth and send several liters of water to the tall treetops every day? So far, the biologists still can’t tell what’s going on. “The transport of water in trees seems to be natural