alleryStart learning →What is the main driver of water movement in the xylem?
ARoot pressure pushing water upwards
BActive pumping by the vessel elements
COsmosis from the phloem sieve tubes
DTranspiration pulling water upwards
Answer & Solution
Correct answer: D. Transpiration pulling water upwards
1. Transpiration is the loss of water from the plant through evaporation at the leaf surface.
2. It is the main driver of water movement in the xylem.
3. Evaporation at the leaf and atmosphere interface creates a tension, and water from the roots is pulled up by it.
4. Xylem conducting cells are dead at maturity, so they cannot pump anything actively.
_Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 30 "Plant Form and Physiology", section 30.5 Transport of Water and Solutes in Plants_
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