5 Written questions
5 Matching questions
- Diffusional resistance of transpirational pathway consists of what two components?
- What is cavitation?
- Water is pulled from the xylem into what?
- What two things is the rate of water flow to a plant dependent upon?
- What is water potential?
- a into the cell walls of the mesophyll where water vapor diffuses through leaf air spaces through the stomatal pore and across the boundary layer
- b boundary layer resistance and leaf stomatal resistance
- c the measurement of free energy of water per unit of volume. (J/m^3)
- d the size of the pressure gradient at the root tip and the soil near by and soil hydraulic conductivity
- e It is the formation of vapor/ gas bubble in flowing water which can rapidly collapse and produce shock waves provding energy to nucleating sites within the xylem.
5 Multiple choice questions
- the mutual attraction of water molecules to themselves
- via casparin cells in the endodermis, they contain radial cell walls composed of suberin (waxy substance) acting as a barrier to water making it cross the cell membrane
- it is the energy used to increase the surface area, the amount of surface area occupied by the interface of air and water. this is important because remember that water is more attracted to itself then to air molecules. (This is what can create contact angels) water generally wants to minimize the surface area at the air water interface
- adhesion and surface tension of water (more negative with increase curvature)
- in plants with very elastic cell walls there can be a change in water potential resulting in a large change in water volume, they can swell with increased water availability.
5 True/False questions
What drives xylem water transport? → the random collisions and exchange of kinetic energy between water molecules driving a movement down concentration gradients
What kind of pressure is between the xylem and cells? → there is a negative hydrostatic pressure
Fisk's first law: → concerted movement of groups of molecules on mass. Responsible for long distance transport in the xylem and for much of the water though the soil and cell walls of plants.
What influences and drives osmosis? → a layer on the outside of the epidermis that is not water permeable
What two driving forces drive the direction and rate of water potential gradients? → solute concentration, pressure and gravity