Tree rings are made of tissue called xylem.

构成年轮的组织被称为木。

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

在木纤维中毛作用无处不在，这些木纤维比人的头发。

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。

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，在木中产生一种负压，把液体的木树液往树方拉。

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，木负责运输水，韧皮负责在光合作用后运输糖。

And if we zoom in, we'll notice its xylem and phloem cells snuggled together, just like they were in the stem.

如果我们放大，我们会注意到它的木韧皮胞依偎在一起，就像它们在茎中一样。

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，木要依赖于三种力量：蒸腾作用，毛作用根压。

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

构成维管组织的胞主要有两种：木韧皮。

So these are xylem sap feeders.

所以这些是木汁液饲养者。

And xylem is just 95% water.

木只有 95% 是水。

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

另一方面，韧皮胞与木胞的运输方向相反。

And pro-tip, xylem is one of my favorite scrabble words.

专业提示，木是我最喜欢的拼字游戏之一。

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

韧皮旁边是树的另一种组织类型：木。

Sclerenchyma supports organs that are fully mature, and similar to xylem, it has cells that are dead inside (physically, not emotionally) .

厚壁组织支持完全成熟的器官，与木相似，它有从内死亡的胞（我指的是身体，而不是情感）。

Carbon and water, more than 1,000 liters of water, in fact, flow freely through the phloem and xylem tubes carry it along.

碳水，实际超过 1000 升的水，自由流动于韧皮木的管道中。

As the plant grows, stem cell clusters called meristems generate new xylem cells, which form bigger pipes to suit the plant's needs.

随着植物的生长，被称为分生组织的干胞簇产生新的木胞，这些胞形成更大的管道以适应植物的需要。

After water flows from the roots to the leaves through the xylem, it can exit the plant through the tiny stomata mouths.

水通过木从根流向叶后，再通过小的气孔口排出植株。

This process, called osmotic movement, creates nutrient-rich xylem sap, which will then travel up the trunk to spread those nutrients through the tree.

这个过程，叫做渗透运动，会产生营养丰富的木树液，这些树液会沿着树干向把营养传送到整棵树。

The earliest wood seems to have been a mechanism for transporting water more effectively than one layer of xylem could on its own.

最早的木材似乎是一种比一层木更有效地输送水的机制。

And where these two forces pull the sap, the osmotic movement at the tree's base creates root pressure, pushing fresh xylem sap up the trunk.

这两种力量推动树液向，树根的渗透作用也产生树压，把新鲜的木树液推树干。