Tree rings are made of tissue called xylem.

构成年轮的组被称为质部。

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

在质纤维中毛细作用无处不在，这些质纤维比人的头发还细。

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

就在韧皮的旁边是的另外一种组质。

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，质部负责运输水，韧皮部负责在光合作用运输糖。

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

这种蒸发，作蒸腾作用，在质中产生一种负压，把液体的质液方拉。

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，质要依赖于三种力量：蒸腾作用，毛细作用和根压。

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

构成维管组的细胞主要有两种：质部和韧皮部。

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，我们会注意到它的质部和韧皮部细胞依偎在一起，就像它们在茎中一样。

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

另一方面，韧皮部细胞与质部细胞的运输方向相反。

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

专业提示，质部是我最喜欢的拼字游戏之一。

So these are xylem sap feeders.

所以这些是质部汁液饲养者。

And xylem is just 95% water.

质部只有 95% 是水。

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

碳和水，实际超过 1000 升的水，自由流动于韧皮部和质部的管道中。

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

韧皮部旁边是的另一种组类型：质部。

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

厚壁组支持完全成熟的器官，与质部相似，它有从内部死亡的细胞（我指的是身体，而不是情感）。

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，被称为分生组的干细胞簇产生新的质部细胞，这些细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.

水通过质部从根流向叶，再通过细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，做渗透运动，会产生营养丰富的质液，这些液会沿着干向把营养传送到整棵。

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.

这两种力量推动液向，根部的渗透作用也产生压，把新鲜的质液推干。

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

最早的材似乎是一种比一层质部更有效地输送水的机制。