transport in plants
- Created by: samsam001
- Created on: 18-03-14 20:10
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- transport in plants
- requirements of plants
- C02- photosynthesising plant cells need a supply of C02 during daylight. They obtain it from the air and aquatic plants from the water
- Oxygen- All living plant cels need oxygen for respiration. Cells that are actively photosynthesising produce more 02 than necessary.
- Inorganic ions and water- all plant cells require a range of inorganic ions and also water. These are taken up by the soil and transported all over the plant
- water transport in plants (process)
- 1- water is uptake from near the root tips
- 2- Water enters the xylem
- 3- water moves up the xylem
- 4- water moves from the xylem to leaf cells
- 5- evaporation of water into leaf air spaces
- 6- transpiration of water vapour though open stomata into the air
- As a side note to this as you go up the stem into the leafs the water potential decrease
- From soil to root hair
- Roots have very thin single cell extensions called root hairs
- they are a specialised exchange surface for the uptake of mineral ions and water
- each root hair is only about 200-250 micrometers across, yet still large enough to be seen with the naked eye
- however although they are small they are thousands on one tiny branch which creates a huge surface area
- soil is made of particles of minerals and humus, between these are air spaces, unless the soil is dry, there is a thin layer of water covering each soil particle
- the root hairs make contact with this water and transport it using osmosis
- The water in the soil moves into the root hairs because there is a lower concentration of solutes in the soil than the plant. Therefore the water potential outside is higher so the water moves along its gradient into the cell
- the root hairs make contact with this water and transport it using osmosis
- Roots have very thin single cell extensions called root hairs
- factors affecting transpiration
- Humidity- this measure the amount of water vapour in the air. In conditions of low humidity, when the air is dry there is a steep water potential gradient, transpiration rates are higher in low humidity
- Temperature- increase in temperature means a rise in kinetic energy meaning an increase in evaporation, an increase in temperature means an increase in transpiration
- requirements of plants
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