Lec10TranspirationAndWaterStress

Formation of water vapor bubble due to the xylem

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Unformatted text preview: itation rocks! Water Stress Text • Effects on physiological processes – Stem hydraulic conductance (stem water transport) • Measure of how readily water moves in the xylem • As stem water potential decreases, stem hydraulic conductivity decreases due to cavitation Water Stress Cavitation = event of water vapor filling a vessel Embolism = result -> a gas bubble that fills the vessel When water potential is negative enough cavitation Results in loss of conductance (and flow) of cavitated vessels the noise is due to the formation of water vapor bubble, due to the xylem cavitating, due to water stress. basically water vapor bubble is building up in the xylem. this causes the flow of the water and more water stress. at night the plant can have a positive pressure and it can get rid of the bubble root pressure is one way to get rid of the bubbles and that is basically during the night that is why you see the water drops on the corner of the leaves called guttation. More about embolism and repair http://5e.plantphys.net/article.php?ch=&id=395 Xylem under repair from embolism http://www.plantphysiol.org/content/early/2 010/09/14/pp.110.162396/relTranspiration suppl/bff1fe3531cea979/suppl/DC1 so basically there is a trigger and that trigger will tell the nucleus to...
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This document was uploaded on 01/17/2014.

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