Xylem and Phloem
- Created by: Jessica Ginnelly
- Created on: 06-01-13 12:44
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- Plant Vessels
- Xylem
- Made from dead cells
- Coated in lignin
- Stops the xylem from collapsing
- Forms patterns
- Annular (rings)
- Reticulate (network of broken rings)
- Incomplete lignification results in pores in the walls known as pits or bordered pits
- The pores help the water to leave from one vessel and pass onto the next one
- No end walls
- No cell contents
- No nucleus or cytoplasam
- Transports water and minerals
- Phloem
- Transports sucrose
- Companion cells
- Dense cytoplasam
- Large nucleus
- Mitochondria
- Plasmodesmata link the companion cells to the sieve tube
- Sieve tube element
- Thin layer of cytoplasam
- No nucleus
- Line up end to end to form a tube
- A source- releases sucrose into the pholem
- A sink- takes sucrose from the pholem
- How sucrose gets into the pholem
- An active process
- 1. H+ ions are pumped out of the companion cells by the use of ATP
- 2. The H+ ions diffuse back into the companion cells with sucrose attached
- 3. The sucrose molecules diffuse into the sieve tube element through the plasmodesmata
- 2. The H+ ions diffuse back into the companion cells with sucrose attached
- Movement of sucrose along the pholem
- 1. Sucrose is actively loaded into the sieve tube element. This results in the reduction of the water potential
- 2. Water moves into the sieve tube element by osmosis. This increases the hydrostatic pressure
- 3. The water moves down the sieve tube element to a lower hydrostatic pressure at the sink
- 4. Sucrose leaves the phloem by diffusion or active transport. This increases the water potential
- 5. Water moves out of the sieve tube element by osmosis. The hydrostatic pressure goes down
- 4. Sucrose leaves the phloem by diffusion or active transport. This increases the water potential
- 3. The water moves down the sieve tube element to a lower hydrostatic pressure at the sink
- 2. Water moves into the sieve tube element by osmosis. This increases the hydrostatic pressure
- 1. Sucrose is actively loaded into the sieve tube element. This results in the reduction of the water potential
- Xylem
- 1. Sucrose is actively loaded into the sieve tube element. This results in the reduction of the water potential
- 2. Water moves into the sieve tube element by osmosis. This increases the hydrostatic pressure
- 3. The water moves down the sieve tube element to a lower hydrostatic pressure at the sink
- 4. Sucrose leaves the phloem by diffusion or active transport. This increases the water potential
- 5. Water moves out of the sieve tube element by osmosis. The hydrostatic pressure goes down
- 4. Sucrose leaves the phloem by diffusion or active transport. This increases the water potential
- 3. The water moves down the sieve tube element to a lower hydrostatic pressure at the sink
- 2. Water moves into the sieve tube element by osmosis. This increases the hydrostatic pressure
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