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Biology
Water's journey through a plant
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Follow water from the soil through roots and xylem to leaves. Change stomatal state and air humidity to explore transpiration.
Choose a state to compare. Stomata do not adjust automatically in this model.
50%
Change the air around the leaf while keeping the soil well watered.
Flow through stomata
× initial level · illustration
At the initial transpiration level.
Initial reference: Open stomata, 50% humidity.
Well-watered soil; fixed temperature and wind.
Paused
Select a structure to see inside. Water moves upward through the xylem; transpiration at the leaves helps create the pull.
Press Play, then select roots, stem or a leaf to look closer.
Liquid waterWater vapour
What draws water upward?
Evaporation at the leaf creates tension. Cohesion between water molecules and adhesion to vessel walls help maintain a connected pathway. Roots should not be treated as a pump pushing the entire water column upward.
Xylem carries water and minerals. Phloem mainly carries organic substances; that flow is outside this model.
Model notes
- The diagram represents a well-watered terrestrial plant at steady state. Leaf and air temperatures are equal and constant; leaf area, wind and the boundary layer are fixed.
- Relative flow is an illustrative index of stomatal conductance and humidity, not measured water loss or an irrigation forecast. The 1× reference has Open stomata and 50% humidity.
- Open, Partly closed and Closed use illustrative conductances of 1, 0.4 and 0. They are not fractions of pore width or an automatic stomatal response model.
- Closed stomata give zero flow through this pathway while water remains in the plant. Cuticular loss, root pressure, water storage and wilting are omitted.
- Magnification and animation timing are not real scales. Markers indicate flow, not molecule counts; only one simplified root pathway is shown, and mineral and sugar transport are not calculated.