How plants drink water: part 6️⃣

Cohesion: water that sticks together, evaporates together.  🤯

Now think back to what we just talked about with transpiration. Can you see how when one water molecule evaporates, it pulls the molecule it’s bound to up with it, which then itself evaporates?

This happens all the way down the chain, and has the effect of pulling the water column in the xylem upwards.

Ok, so what do we know so far? We know that water sticks together, water evaporates during transpiration, and this evaporation causes water to be pulled up out of the xylem. But what would happen to the water if transpiration stopped, like it does at nighttime? Would all the water fall back down to the ground so the plant would have to start all over again? Nope.

To see why, there's one more force at play you need to understand. Read about adhesion here.


This blog post is part of a series on how plants drink water. You can navigate to any post in the series by using the menu here:

  1. Pass me the water, please. 💦
  2. The root of the matter. 🧐
  3. Oh xylem, my xylem. 😍
  4. Transpiration: take a breath. 🤭
  5. Water sticks together. 😛
  6. Cohesion: water that sticks together, evaporates together. 🤯
  7. Adhesion: liquids stick to the surface of their container. 🤮
  8. How do these forces work together? 🤔
  9. Final Thoughts 🙌

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