Tall trees move water from roots to leaves without any pump. Which combination of water properties accounts for this upward transport?

Core Concept

Evaporation from leaf mesophyll generates negative pressure, or tension, in the continuous liquid thread running down the xylem. Because water molecules hydrogen bond to one another, cohesion keeps that column unbroken even under strong pull in tall trees. Adhesion between water and the hydrophilic cellulose-rich walls of tracheids and vessel elements anchors the column against gravity. Together these passive forces draw replacement water up from the roots, driven ultimately by solar-powered evaporation rather than any pump.