Water and nutrients flow both up and down {circulation, plant} in xylem and phloem.
Water-molecule attractions pull water from root through stem to leaf {cohesion theory}.
Leaf-stomata water evaporation {transpiration}| pulls water up from roots. Transpiration depends on osmosis. Transpiration causes forests to be cool and humid.
Phloem fluid goes from leaves to stems to roots {translocation, plant}. Low temperature, low oxygen, or poison can block translocation.
Xylem and phloem fluid {plant sap} {sap}| contains latex, which aids circulation.
Plant sap contains organic molecules {latex}| that aid circulation. Rubber, chicle, and opium are latexes.
Salts and water absorbed by roots create water pressure {root pressure} that pushes water from roots through stem to leaves.
Root cells actively transport minerals. Root cells absorb water by osmosis, to dilute minerals pumped into root cells. Water absorption causes pressure {turgor pressure} on cell walls. Turgor pressure provides cell support and shapes non-woody plants.
Too-low cell water makes low turgidity, and cells can burst {plasmolysis}.
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Date Modified: 2022.0225