Plant transport, storage and gas exchange Flashcards
Plants make their own food meaning they are
Autotrophic
Plants transport
Water, Carbon dioxide, oxygen, minerals and plant growth regulators for metabolism
Why is water needed
Photosynthesis, cell metabolism, growth and cell turgidity
Water uptake by roots
- Water is absorbed by root hairs by osmosis
- Water enters the cytoplasm
- Water moves from cell to cell by osmosis
How are root hairs adapted
- Provide a large surface area
- No cuticle
- Have thin walls
What is the transport of water caused by
- Root pressure
2. Transpiration
Root pressure
forced upward movement of water and minerals from the root to stem
Transpiration
Loss of water vapour from a plant through stomata
Cohesion-Tension theory
- Water evaporates at the leaf in transpiration
- Loss of water creates tension
- Tension pulls water up as a continuous stream creating a transpiration stream
- Water molecules are attracted to each other in a process called cohesion
- Water molecules are attracted to the xylem in a process called adhesion
- Root pressure is a force generated by the root, as water is absorbed, it pushes water up the stem
Name 2 scientists associated with the cohesion-tension model of transport
- Dixon
- Joly
Mineral uptake and transport
- Minerals are absorbed into the root hairs by active transport
- Passed through xylem and carried up the stem
- Root hair cells are adapted as mitochondria supplies energy
- Minerals needed are calcium(forms middle lamella) and magnesium (produce chlorophyll)
Carbon dioxide uptake and transport
- CO2 diffuses in through the stomata of the leaf from the atmosphere
- Respiration in plant cells provides CO2 to the plant
- CO2 diffuses through the air spaces in the leaf to the ground tissue or mesophyll cells
Transport and Oxygen
- O2 is a product of photosynthesis
- Some O2 is used in plant respiration and excess O2 diffuses into the atmosphere through the stomata
Transport of the photosynthetic product glucose
- Translocated as sucrose in phloem sieve tubes
- Sucrose is the main transport carbohydrate in phloem
Transport of growth regulators
- Diffusion and active transport
Modified root
- Taproot
- Carrots
- Glucose
Modified stem
- Potato tuber
- Starch
Modified leaf
- Bulb is an underground stem with leaves
- Onions
- Glucose