Tree rings are made of tissue called xylem.

构成年轮的组织被称为木质部。

This capillary motion is in full effect in xylem filaments thinner than human hair.

在木质纤维中毛细作用无处不在，这些木质纤维比人的头发还细。

Right beside the phloem is the tree's other tissue type: the xylem.

就在韧皮的旁边是树的另外一种组织叫木质。

This evaporation, called transpiration, creates negative pressure in the xylem, pulling watery xylem sap up the tree.

这种蒸发，叫作蒸腾作用，在木质中产生一种负压，把液体的木质树液往树上方拉。

Through that space stretches the vascular bundle, with xylem to transport water and phloem which transport sugars after photosynthesis.

通过这个空间，延伸出维管束，木质部负责运输水，韧皮部负责在光合作用后运输糖。

And there are two main types of cells that make up that vascular tissue: xylem and phloem.

构成维管组织的细胞主要有两种：木质部和韧皮部。

So these are xylem sap feeders.

所以这些是木质部汁液饲养者。

And xylem is just 95% water.

木质部只有 95% 是水。

Phloem cells, on the other hand, transport stuff mostly in the opposite direction as xylem cells.

另一方面，韧皮部细胞与木质部细胞的运输方向相反。

To accomplish this herculean task, the xylem relies on three forces: transpiration, capillary action, and root pressure.

要完成这样艰巨的任务，木质要依赖于三种力量：蒸腾作用，毛细作用和根压。