Via cohesion tension, how does a plant take up water? Water molecules are COHESIVE. This means that they form hydrogen bonds between molecules, and they stick together, forming a chain. This is an unbreakable chain up the xylem to the mesophyll, and, as water evaporates from the mesohpyll on the leaf surface, more water is drawn up, due to the aforementioned cohesive properties.
How does water enter a root hait cell? Water potential is high in the soil, and the water potential in the root hair cell is low, due to the sugars, amino acids, and ions dissolved in it. This creates a waer potential gradient and water moves in by osmosis.
Root cortex - The simplastic pathway means going through the cells. The root hair cell will now have high water pressure, whereas the first cellin the cortex will have low. This means water will move in via osmosis. Then, the next cell will have a lower water potenital then the one the water had just moved into. So water will move into this one via osmosis. This will continue, and whilst this is happening, the water potential of the first few cells has lessened after the water moves on to the cell after, meaning more water can move in.
The Apoplastic way involves moving through the cell wall of the root cortex cells. Due to the cohesive properties of water, it gets pulled along in a unbroken steam, with little resistence, due to the mesh like structure of cellulose having water filled gaps.
Endodermis - Xylem. The water travelling the apoplastic pathway can no longer continue in that pathway, due to the casparian strip, which is waterproof, and so joins the Symplastic pathway, to continue through the endodermis. Endodermal cells actively transport minerals into the xylem, lowering it's water potential, and causing a water potential gradient that allows water to move into the xylem via osmosis.
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