Plant Transport

What does xylem transport?

Water and dissolved minerals from roots toward shoots.

What does phloem transport?

Sugars and other organic solutes from sources to sinks.

What is transpiration?

Loss of water vapor from plant aerial tissues, primarily through stomata.

What is the cohesion-tension mechanism?

Transpiration creates tension that pulls a continuous column of cohesive water through xylem.

What is cohesion in water transport?

Attraction between water molecules that helps maintain a continuous column.

What is adhesion in water transport?

Attraction between water molecules and xylem walls.

What is root pressure?

Positive pressure generated in roots by solute accumulation and water entry; it can push xylem sap upward.

What is the endodermis?

A selective cell layer in roots regulating movement into the vascular cylinder.

What is the Casparian strip?

A waterproof band in endodermal walls that forces water/solutes through cell membranes before entering the stele.

What is stomatal conductance?

The degree to which stomata allow gas and water-vapor movement.

What causes stomata to open?

Guard cells take up solutes and water, become turgid, and bow apart.

What causes stomata to close?

Guard cells lose turgor, reducing the stomatal opening.

What is a source in phloem transport?

A tissue that exports sugars, such as a photosynthesizing mature leaf.

What is a sink in phloem transport?

A tissue that imports or stores/uses sugars, such as roots, fruits, or growing tissues.

What is pressure-flow in phloem?

Sugar loading draws in water and raises pressure at sources; pressure drives sap toward lower-pressure sinks.

What is translocation?

Movement of sugars and other solutes through phloem.

What is guttation?

Release of liquid water from leaf margins through hydathodes, often under root pressure.

How do plants balance CO₂ uptake with water conservation?

By regulating stomatal opening, balancing photosynthesis against water loss.