That's a wonderful measurement method. When colleagues don't know that water pressure can be negative for some time, I often use trees as an example. If they ask for an argument from authority, I point to one of Holbrooke's papers. Now I can refer them to a video. Thanks!
Awesome material! I wonder if sealing of pressure bomb in the lid, where leaf goes through a hole is not an issue? If it's not tight enough, you might have leaks, lose pressure and get false readings. If it's too tight, then you might squeeze the leaf and make it harder for water to flow, getting false readings again. Or is it not a problem?
These are great questions! I checked in with Jess and here's what she had to say: You can have leaks- you would hear them or you can even feel them if you put your finger above it! If the leak is small, it's not an issue because the gauge is measuring the pressure *in* the chamber, not the pressure of the air moving in/out. So, if there is a leak, it is being accounted for by the gauge reading. But typically you try (and can successfully!) avoid them. You can damage the plant if you squeeze too tight - and one sign of that is you have liquid leaking out of the petiole before you even start pressurizing! So that's one way to know if damage has occurred.
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That's a wonderful measurement method. When colleagues don't know that water pressure can be negative for some time, I often use trees as an example. If they ask for an argument from authority, I point to one of Holbrooke's papers. Now I can refer them to a video. Thanks!
I loved this one! I’m glad you gave us that close-up shot of the xylem. Also I want to check out a forest canopy someday now :)
Awesome material! I wonder if sealing of pressure bomb in the lid, where leaf goes through a hole is not an issue? If it's not tight enough, you might have leaks, lose pressure and get false readings. If it's too tight, then you might squeeze the leaf and make it harder for water to flow, getting false readings again. Or is it not a problem?
These are great questions! I checked in with Jess and here's what she had to say:
You can have leaks- you would hear them or you can even feel them if you put your finger above it! If the leak is small, it's not an issue because the gauge is measuring the pressure *in* the chamber, not the pressure of the air moving in/out. So, if there is a leak, it is being accounted for by the gauge reading. But typically you try (and can successfully!) avoid them. You can damage the plant if you squeeze too tight - and one sign of that is you have liquid leaking out of the petiole before you even start pressurizing! So that's one way to know if damage has occurred.
Thank you!
I love this!
So interesting!
haHAA