The Movement of Water through the Roots
- Created by: Jessica
- Created on: 13-01-13 10:05
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- The Movement of Water through roots
- Plants need to conserve water, and so are covered by a waterproof layer.
- Root hairs are therefore the only part of the plant that can absorb water.
- The dicotyledonous root contains:
- Root hair
- Provide large surface area
- Thin surface layer across which materials move easily
- Have a low water potential due to the minerals, sugars and amino acids dissolved inside them.
- The soil has a high water potential.
- Water moves by osmosis from the soil solution into the root hair cells DOWN the water potential gradient.
- The soil has a high water potential.
- Phloem (outside tubes)
- Xylem (inner "plus")
- Endodermis surrounding ploem and xylem
- Casparian ***** made up of a waxy, waterproof substance
- Protoplast
- Root hair
- The dicotyledonous root contains:
- Root hairs are therefore the only part of the plant that can absorb water.
- The Apoplastic Pathway
- The water molecules are drawn into the endodermal cells, and become cohesive.
- The created tension pulls the water along the cell walls of the cortex.
- Cellulose walls have a mesh-like structure with water filled spaces, so there is no resistance to the pull of water.
- The water molecules are drawn into the endodermal cells, and become cohesive.
- The Symplastic Pathway
- Occurs in the cytoplasm of the cells due to osmosis.
- Water moves through the PLASMODESMATA in the cell walls.
- Water entering by osmosis increases the water potential of the root hair cell.
- The water potential gradient is set up across all the cells in the cortex, so water is carried alogn the cytoplasm from the root hair cell to the endodermis.
- Plants need to conserve water, and so are covered by a waterproof layer.
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