Transport, Storage and Gas Exchange Of Flowering Plants Flashcards
Autotroph
Makes it’s own food
Why do plants need a transport system?
To provide materials needed for various plant metabolic processes including photosynthesis, respiration etc..
What is transported?
- Water
- Carbon dioxide
- Minerals
- Carbohydrates produced by Photosynthesis
Water uptake
Water enters the root hair cells by osmosis. Root hairs are adapted by having thin walls and being so numerous so there is a large surface area.
Water movement through the root
Water moves by osmosis from the root hairs into the ground tissue from cell to cell until it reaches the xylem
Upward movement of water
- Root pressure
As water moves into the root by osmosis it builds up a pressure that pushes (forces) water up the xylem
Upward movement of water
- Transpiration
As water evaporates from the lead by transpiration, more water is pulled upwards through the xylem into the leaf.
Control of water loss from leaf
- Presence or absence of cuticle
Water cannot pass through the cuticle. The presence of a cuticle helps reduce excessive water loss.
Control of water loss from the leaf
- Opening & closing of stomata
Stomata opening increases water loss
Stomata closing reduces water loss
Control of water loss from the leaf
- Location of the stomata
Stomata are normally located on the lower surface of the leaf because it’s not in direct sunlight and it’s cooler. This helps reduce water loss by transpiration
Mineral uptake & transport
Some minerals are taken up by diffusion and some by active transport.
C02 sources
- Diffuses from the air in through the stomata
- Produced in the plant by respiration
Glucose fate
Used in respiration to provide energy for the plant. Glucose can be converted into starch for long term food storage. Starch & glucose transported around the plant in the phloem.
Modified root (food storage)
Carrot
Dicot plants
Modified stem
Potato
Modified leaves
Onion bulbs
(Swollen by starch)
Gas exchange
In the stem, lenticles allow for gas exchange, carbon dioxide diffuses into air spaces on the ground tissue and then into cells. Oxygen diffuses from ground tissue into air. Water vapour leaves in same way
Cohesion
Similar molecules sticking together e.g water molecules sticking to water molecules
Adhesion
Different molecules sticking together e.g water molecules sticking to the xylem
The cohesion - tension model
Overview
Check notes. I’m too tired to write out this bullshit..
Stomatal opening & closing
Guard cells open and close (stoma) stomata. When water enters the guard cells by osmosis they become turgid/swollen. As the cells are joined at tips, they increase in size, buckle outwards, therefore opening stoma. When they lose water they shrink and close.
Control of stomatal opening and closing
- The major factor is the concentration of carbon dioxide in the air spaces of the leaf.
- High concentration = Stomata close = night (respiration)
Low concentration = stomata open = Day (photosynthesis)
