Transport in Plants

Pith

Cortex

Phloem

Cuticle

Transporting water by osmosis

Providing ATP for translocation

Protecting the plant from pests

Storing water for transpiration

It decreases

It increases

It stays the same

It drops to zero

Through the cytoplasm

Through the cell walls and intercellular spaces

Through the vacuole

Through the phloem sieve tubes

Increased light intensity leads to stomatal closure, decreasing transpiration

Increased light intensity leads to stomatal opening, increasing transpiration

Light intensity has no effect on the rate of transpiration

Increased light intensity decreases the temperature of the leaf, decreasing transpiration

The movement of sucrose from leaves to roots

The continuous flow of water and ions from roots to leaves

The flow of water through the phloem sieve tubes

The movement of water into the roots by active transport

It becomes more positive as sucrose is added

It becomes more negative as sucrose is added

It stays the same because sucrose is not osmotic

It becomes more negative as water leaves the phloem

The active transport of mineral ions into the xylem.

The evaporation of water into the air spaces within the leaf.

The movement of water through the symplast of the mesophyll.

The condensation of water vapor on the surface of the leaf.

Large, thin leaves with many stomata on the upper surface.

A thin cuticle and lack of lignin in the stem.

Sunken stomata and a thick waxy cuticle.

Xylem vessels with very large diameters.

From B to A because B has a more negative water potential.

From A to B because water moves from higher to lower water potential.

There is no net movement as they are in equilibrium.

From A to B because water moves from lower to higher solute concentration.

To replace water lost by transpiration

To keep the roots warm

To wash away excess minerals

To prevent the soil from drying out

Only through the cell walls

Only through the cytoplasm

Via both cell walls and through the cells

Through the phloem vessels

It allows more space for the large vacuole

It makes the cell lighter

It stops the cell from using energy

It prevents the nucleus from functioning

Anchoring the plant

Absorbing water

Absorbing minerals

Absorbing carbon dioxide for photosynthesis

$-1.0$ MPa

$-0.4$ MPa

$0.4$ MPa

$1.0$ MPa

Water can move through the cell walls of the cortex

Water can move from cell to cell via plasmodesmata

Water can bypass the endodermis through the apoplast

Water potential decreases as you move from the epidermis to the xylem

To allow for active transport of water

To provide a low-resistance pathway for mass flow

To prevent water from reaching the leaves too quickly

To ensure that osmosis can occur across the vessel walls

Water moves into the phloem from the xylem via osmosis to create a pressure gradient for sugar transport.

Water is pumped by the xylem into the phloem to provide kinetic energy.

Water moves from the soil into the xylem due to the pressure generated by phloem unloading.

Water evaporates from the phloem to cool the plant.

The water potential of the soil becomes too positive for the plant to absorb it.

The lack of oxygen prevents aerobic respiration, stopping the active transport of ions needed for water uptake.

The excess water enters the plant too quickly, causing the cells to burst.

The roots secrete toxins in response to water, which block the xylem.

The valves at the base of the xylem vessels.

The one-way nature of the plasmodesmata.

The high concentration of solutes maintained in the xylem by active transport.

The positive pressure from the leaves pushing the water down.

Smaller surface area means more water loss

Larger surface area means more water loss

Surface area does not affect water loss

Larger surface area means less water loss

To wash the leaves

To prevent air bubbles from entering the xylem

To increase the rate of photosynthesis

To keep the plant cool

Light intensity

Humidity

Soil nitrogen levels

Temperature

Large leaves

Thin cuticles

Sunken stomata

Increased number of stomata

Osmosis through the upper epidermis

Diffusion of water vapor through the stomata

Active transport through the guard cells

Bulk flow through the palisade layer

The boundary layer becomes thicker, decreasing transpiration.

The boundary layer is removed or thinned, increasing transpiration.

The boundary layer becomes warmer, increasing transpiration.

Wind has no effect on the boundary layer, only on temperature.

Vapor

Liquid

Solid

Plasma

From the air into the leaf

From the sub-stomatal cavity out through the stomata

There will be no net movement

Water will move from the air into the xylem directly through the cuticle

Epidermis

Pericycle and/or living cells within the vascular cylinder

Xylem vessels (which are dead)

Pith

By changing the wind speed manually

By adjusting stomatal aperture to change leaf resistance

By changing the distance between the sun and the leaf

By increasing the nitrogen content of the air

It is higher at the sink

It is lower at the sink

It is the same at both

It is zero at both

It is completely inactive

It transports stored sugars from roots to developing buds

It transports water from the air to the roots

It performs photosynthesis in the dark

In the center of the xylem

Between the arms of the xylem

In the epidermis

Outside the endodermis

Active loading

Unloading

Transpiration

Evaporation

The distance from the source

The rate at which it removes and consumes solutes from the phloem

The height of the sink above the ground

The number of stomata on the sink organ

The xylem vessels

The epidermis

The phloem sieve tubes

The pith in the center

To transfer water from the roots to the leaves

To facilitate the loading of solutes into the phloem using an increased surface area

To transfer pollen from the anther to the stigma

To act as temporary storage for starch

Mesophyll $\\rightarrow$ Apoplast $\\rightarrow$ Companion Cell $\\rightarrow$ Sieve Tube $\\rightarrow$ Sink Cell

Sieve Tube $\\rightarrow$ Companion Cell $\\rightarrow$ Apoplast $\\rightarrow$ Mesophyll $\\rightarrow$ Sink Cell

Xylem $\\rightarrow$ Mesophyll $\\rightarrow$ Sieve Tube $\\rightarrow$ Companion Cell $\\rightarrow$ Sink Cell

Companion Cell $\\rightarrow$ Sieve Tube $\\rightarrow$ Mesophyll $\\rightarrow$ Apoplast $\\rightarrow$ Sink Cell

It is a bulk flow of liquid driven by a pressure gradient, which is limited by the viscosity and resistance of the tube.

It depends on the speed of enzyme reactions in the companion cells.

It is limited by the rate of $CO_2$ diffusion into the stomata.

The P-proteins in the sieve tubes act as tiny motors that move the sap at a constant speed.

Translocation may slow down because less water is available to enter the phloem from the xylem at the source.

Translocation will speed up as the plant tries to move all its sugar to the roots for safety.

Translocation will remain unaffected because it is an active process and does not rely on water.

The phloem will reverse its direction to bring water from the fruits back to the leaves.