Related Experiment Video
Updated: Dec 29, 2025
08:05
Microtensiometer for Confocal Microscopy Visualization of Dynamic Interfaces
Published on: September 9, 2022
2.7K
Dynamic surface tension of xylem sap lipids
Jinlong Yang1, Joseph M Michaud2, Steven Jansen3
1Department of Mechanical Engineering, University of Hawaii at Manoa, 2540 Dole Street, Holmes Hall 302, Honolulu, HI 96822, USA.
Tree Physiology
|February 8, 2020
Summary
Xylem sap
Area of Science:
- Plant Physiology
- Biochemistry
Background:
- Traditionally, xylem sap surface tension was assumed to be similar to pure water.
- This assumption was based on the idea that lower surface tension increases vulnerability to air seeding and embolism.
- Xylem sap contains insoluble lipid surfactants coating surfaces, influencing air seeding under negative pressure.
Purpose of the Study:
- To estimate the dynamic surface tension of apoplastic lipid layers in xylem.
- To investigate the influence of local lipid concentration and surface area on surface tension.
- To reconcile xylem surface tension with air-seeding and embolism theories.
Main Methods:
- Extraction of apoplastic lipids from xylem sap of four woody angiosperm plants.
- Constrained drop surfactometry to measure time-dependent and surface area-regulated surface tensions.
- Analysis of lipid layer behavior under varying surface area conditions.
Main Results:
- Xylem lipids exhibited potent surface activity, reaching equilibrium surface tension around 25 mN m⁻¹.
- Surface tension varied dynamically between 19 mN m⁻¹ and 68 mN m⁻¹ with surface area changes (50-160%).
- Lipid films exist in metastable nonequilibrium states (compression or expansion) depending on local surface area.
Conclusions:
- Low dynamic surface tension in xylem is compatible with cohesion-tension and air-seeding theories.
- Findings support the existence of lipid-coated nanobubbles in xylem sap.
- The study reconciles observed embolism vulnerabilities with physical properties of xylem lipids and pit structures.
Keywords:
DGDGMGDGapoplastic xylem lipidsconstrained drop surfactometryembolismgalactolipidsphospholipidsxylem surfactantMore Related Videos
Related Concept Videos
02:57Surface Tension, Capillary Action, and Viscosity
32.3K
Surface Tension
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
32.3K
01:16Surface Tension and Surface Energy
2.8K
When a paint brush is immersed in water, the bristles wave freely inside the water. When it is taken out, the bristles stick together. The reason behind this effect is surface tension.
Consider a beaker filled with liquid. The bulk molecules in the liquid experience equal attractive forces on all sides with the surrounding molecules. However, the surface molecules experience a net attractive force downward due to the bulk molecules. The surface of the liquid behaves like a stretched membrane,...
Consider a beaker filled with liquid. The bulk molecules in the liquid experience equal attractive forces on all sides with the surrounding molecules. However, the surface molecules experience a net attractive force downward due to the bulk molecules. The surface of the liquid behaves like a stretched membrane,...
2.8K
01:22Surface Tension of Fluid
1.2K
Surface tension is a fundamental property of fluids, occurring at the boundary between a liquid and a gas or between two immiscible liquids. This phenomenon arises from the cohesive forces between molecules at the fluid's surface, creating an effect similar to a stretched elastic membrane. Inside each fluid, molecules are equally attracted in all directions by neighboring molecules, but surface molecules experience a net inward force, resulting in surface tension.
Surface tension varies...
Surface tension varies...
1.2K
02:03Xylem and Transpiration-driven Transport of Resources
26.1K
The xylem of vascular plants distributes water and dissolved minerals that are taken up by the roots to the rest of the plant. The cells that transport xylem sap are dead upon maturity, and the movement of xylem sap is a passive process.
26.1K
01:14Adhesion
43.2K
Adhesion occurs when one type of molecule is attracted to a different molecule. Water exhibits adhesive properties in the presence of polar surfaces, such as glass or cellulose in plants. For instance, when water is poured into a glass, the positively charged hydrogen molecules of water are more attracted to the negatively charged oxygen molecules in the silica than to the oxygen in neighboring water molecules.
Capillary action is a result of water’s adhesive tendencies. When a narrow...
Capillary action is a result of water’s adhesive tendencies. When a narrow...
43.2K
01:13Excess Pressure Inside a Drop and a Bubble
3.0K
The shape of a small drop of liquid can be considered spherical, neglecting the effect of gravity. This drop can further be considered as two equal hemispherical drops put together due to surface tension. The forces acting on the spherical drop are due to the pressure of the liquid inside the drop, the pressure due to air outside the drop, and the force due to the surface tension acting on the two hemispherical drops.
3.0K