Transport In Plants 3.1.3

Front 1

Leaf of young herbaceous plant

Back 1

Midrib is the main vein of the leaf, the vein contains the vascular tissue which then branches off into smaller veins. The veins have a role in the transport and support in the leaf.

Front 2

Xylem

Back 2

Transports water and mineral ions from the roots to shoots and gives support to the plant via lignin in walls.

Front 3

Xylem Structure

Back 3

Tracheids- long and narrow tapered cells with pits, Vessel elements - thickened cell walls, Parenchyma - food store, Sclerenchyma cells- strength and support.

Front 4

Phloem

Back 4

Tissue in plants that is responsible for transporting food and nutrients from the leaves to other parts of the plant.

Front 5

Phloem Structure

Back 5

Main cells are sieve tube elements, these form sieve tubes. Sieve tube is hollow with sieve plates forming between the indivifual cells. The plates are perforated allowing easy movement of substances. Lack of organelles.

Front 6

Plasmodesmata

Back 6

They exist between sieve tube elements and companion cells. These are channels through the cell walls to link the cytoplasm of both cells.

Front 7

Cohesion-Tension theory

Back 7

The movement of water through a plants xylem is largely due to the evaporation of water vapour from the leaves and the cohesive and adhesive properties exhibited by water molecules.

Front 8

Transpiration

Back 8

Evaporation of water vapour lost from plants via diffusion into the atmosphere via the stomata. The three process'; Osmosis from the xylem vessels to mesophyll cells, Evaporation from the surface, Diffusion out via the stomata.

Front 9

Factors affecting the rate of transpiration

Back 9

Light, Relative humidity, temperature, air movement, soil-water availability.

Front 10

Root hair cells

Back 10

Roots uptake water and mineral ions, they increase the surface area for absorbtion of the substances. The uptake is a passive process (osmosis), the uptake of minerals can be active (active transport) or passive (diffusion).

Front 11

Apoplastic Pathway (movement of water through roots)

Back 11

Through the spaces in the cell wall, by diffusion, reaches endodermis and water is stopped by Casparian strip and we enter the symplastic pathway.

Front 12

Symplastic Pathway (movement of water through roots)

Back 12

Through the cytoplasm and plasmodesmata, moves by osmosis.

Front 13

Translocation

Back 13

Transport of assimilates in the phloem tissue, products are transported from source to sink.

Front 14

Phloem loading

Back 14

H+ ions actively transported out of companion cells, H+ ions diffuse back into companion cells through co-transporter carrying sucrose, sucrose diffuses down the concentration gradient into phloem, reduces water potential so water moves in.

Front 15

Phloem unloading

Back 15

Mainly diffusion, to maintain concentration gradient sucrose is converted into other molecules, water moves out the phloem.