Transport Mechanisms in Plants: Xylem and Phloem

Air-Water Meniscus

Air bubble formed in potometer during measurement.

Acclimatise

Adjusting to new environmental conditions.

Lignin

Structural component in xylem cell walls.

Phloem

Tissue transporting sugars throughout the plant.

Translocation

Movement of organic substances in plants.

Transpiration

Water loss from plant leaves to atmosphere.

Potometer

Apparatus to estimate plant transpiration rates.

Xylem

Tissue transporting water from roots to leaves.

Cohesion-Tension Theory

Explains water movement via cohesion and tension.

Stomata

Pores on leaves allowing gas exchange.

Radioactive Tracer

Used to track movement of substances in plants.

Autoradiography

Technique to visualize radioactive substance distribution.

Pressure Gradient

Difference in pressure driving fluid movement.

Sieve Plates

Structures in phloem aiding solute transport.

Metabolic Inhibitor

Substance halting ATP production in cells.

Concentration Gradient

Difference in solute concentration across space.

Capillary Tube

Narrow tube facilitating water movement in potometer.

Cutting Technique

Method for preparing plant tissue for microscopy.

Stain

Chemical used to visualize specific cell components.

Bulge Formation

Evidence of downward flow in phloem after bark removal.

Sugar Sinks

Locations where sugars are utilized or stored.

Environmental Factors

Conditions affecting transpiration rates, like temperature.

Water Uptake

Process of roots absorbing water from soil.

Experimental Controls

Conditions kept constant during scientific experiments.

Photosynthesis

Process converting light energy into chemical energy.

Cohesion

Attraction between water molecules aiding transport.

Tension

Negative pressure created by water evaporation.

Stomatal Opening

Process allowing CO2 entry and water loss.

Mass Flow Hypothesis

Theory explaining transport of substances in plants.

Sieve Tube Elements

Living cells in phloem that transport solutes.

Companion Cells

Support sieve tube elements with energy and functions.

Source

Area where solutes are produced in plants.

Sink

Area where solutes are used or stored.

Water Potential

Potential energy of water in a system.

Osmosis

Movement of water across a semi-permeable membrane.

Humidity

Amount of water vapor in the air.

Light Intensity

Brightness affecting plant transpiration rates.

Temperature

Heat affecting water evaporation rates in plants.

Wind

Air movement increasing transpiration rates.

Vessel Elements

Dead cells forming xylem vessels for transport.

Evaporation

Process of water turning into vapor.

Transpiration Rate

Speed of water loss from plant surfaces.

Sucrose

Main sugar transported in phloem.

Assimilates

Substances transported for plant growth.

Enzymes

Proteins facilitating chemical reactions in plants.