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Absorb soil solution, which consists of water and dissolved mineral ions
Absorb soil solution, which consists of water and dissolved mineral ions
Forums The Undercurrent it's literally just biology
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Soil solution passes along epidermal walls and extracellular spaces into root cortex → exposes cortex cells to soil solution → increases SA for absorption
Soil solution passes along epidermal walls and extracellular spaces into root cortex → exposes cortex cells to soil solution → increases SA for absorption
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Endodermis (innermost layer in the root cortex) = controls selective passage of minerals from cortex into vascular cylinder (and then xylem), screens out unneeded/toxic stuff
Endodermis (innermost layer in the root cortex) = controls selective passage of minerals from cortex into vascular cylinder (and then xylem), screens out unneeded/toxic stuff
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Symplastic route - minerals were already screened (had to cross a plasma membrane when they entered this route in epidermis or cortex), so they can continue through the plasmodesmata of endodermal cells into the vascular cylinder
Symplastic route - minerals were already screened (had to cross a plasma membrane when they entered this route in epidermis or cortex), so they can continue through the plasmodesmata of endodermal cells into the vascular cylinder
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Apoplastic route - minerals are blocked from the vascular cylinder by the Casparian strip (in walls of endodermal cells, made of waxy suberin), so they must first cross the selectively permeable plasma membrane of the endodermal cells before entering vascular cylinder
Apoplastic route - minerals are blocked from the vascular cylinder by the Casparian strip (in walls of endodermal cells, made of waxy suberin), so they must first cross the selectively permeable plasma membrane of the endodermal cells before entering vascular cylinder
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Endodermal cells and living cells of vascular cylinder (symplast) discharge water/minerals into their cell walls (apoplast) via diffusion and active transport → tracheids and vessel elements of xylem (apoplast) → shoot system via bulk flow
Endodermal cells and living cells of vascular cylinder (symplast) discharge water/minerals into their cell walls (apoplast) via diffusion and active transport → tracheids and vessel elements of xylem (apoplast) → shoot system via bulk flow
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Transpiration - loss of water vapor from leaves, role in transporting xylem sap from roots to leaves
Transpiration - loss of water vapor from leaves, role in transporting xylem sap from roots to leaves
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At night (no transpiration) - root cells pump mineral ions into xylem → lowers water potential in vascular cylinder → water flows in from root cortex → root pressure (pushes xylem sap)
At night (no transpiration) - root cells pump mineral ions into xylem → lowers water potential in vascular cylinder → water flows in from root cortex → root pressure (pushes xylem sap)
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Guttation - root pressure causes more water to enter the leaves than is transpired → droplets on leaves in the morning
Guttation - root pressure causes more water to enter the leaves than is transpired → droplets on leaves in the morning
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Minor, too weak to overcome gravity, can’t keep pace with transpiration in daytime
Minor, too weak to overcome gravity, can’t keep pace with transpiration in daytime
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Cohesion-tension hypothesis (pulling xylem sap) - transpiration pulls xylem sap upwards, and the cohesion of water molecules transmits this pull along the length of the plant
Cohesion-tension hypothesis (pulling xylem sap) - transpiration pulls xylem sap upwards, and the cohesion of water molecules transmits this pull along the length of the plant
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In leaves - internal air spaces expose mesophyll to CO2, saturated with water vapor due to moist walls of cells
In leaves - internal air spaces expose mesophyll to CO2, saturated with water vapor due to moist walls of cells
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Air outside the leaf is drier (lower water potential) → water diffuses out of the leaf via the stomata
Air outside the leaf is drier (lower water potential) → water diffuses out of the leaf via the stomata
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Water adheres to the cellulose microfibrils of the mesophyll cell wall → water film
Water adheres to the cellulose microfibrils of the mesophyll cell wall → water film
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Water evaporates from the film → air-water interface retreats into the cell wall and curves (due to high surface tension of water) → tension increases (more negative water pressure) → water from hydrated parts of the leaf are pulled to this area to reduce the tension → “pulling” is transferred to xylem by cohesion
Water evaporates from the film → air-water interface retreats into the cell wall and curves (due to high surface tension of water) → tension increases (more negative water pressure) → water from hydrated parts of the leaf are pulled to this area to reduce the tension → “pulling” is transferred to xylem by cohesion
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Negative pressure potential of the leaves pulls water from the xylem as a result of water moving from higher to lower potential
Negative pressure potential of the leaves pulls water from the xylem as a result of water moving from higher to lower potential
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Adhesion of water molecules to hydrophilic cellulose in xylem walls offsets the force of gravity
Adhesion of water molecules to hydrophilic cellulose in xylem walls offsets the force of gravity
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Having you as a Voltie would be awesome.