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10 Cards in this Set
- Front
- Back
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Function of Xylem?
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Xylem cells have extra reinforcement in their cell walls, and this helps to support the weight of the plant, Xylem transports water and solutes from the roots to the leaves.
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Function of Phloem?
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Phloem is composed of still-living cells that transport sap. The sap is a water-based solution, but rich in sugars made by the photosynthetic areas.
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Transpiration definition?
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Loss of water vapour from plant leaves by evaporation of water at the surfaces of the mesophyll cells followed by diffusion of water vapour through the stomata
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How does water move up the xylem?
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Water from the roots is pulled up by this tension. At night, when stomata close and transpiration stops, the water is held in the stem and leaf by the cohesion of water molecules to each other as well as the adhesion of water to the cell walls of the xylem vessels and tracheids.
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How and why does wilting occur?
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Wilting refers to the loss of rigidity of non-woody parts of plants. This occurs when the turgor pressure in non-lignified plant cells falls towards zero, as a result of diminished water in the cells
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What effects transpiration?
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Light, temperature, wind, humidity.
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How does light affect transpiration?
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In bright light transpiration increases, The stomata (openings in the leaf) open wider to allow more carbon dioxide into the leaf for photosynthesis.
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How does temperature affect transpiration?
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Transpiration is faster in higher temperatures, Evaporation and diffusion are faster at higher temperatures,
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How does wind affect transpiration?
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Transpiration is faster in windy conditions,Water vapour is removed quickly by air movement, speeding up diffusion of more water vapour out of the leaf.
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How does humidity affect transpiration?
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Transpiration is slower in humid conditions, Diffusion of water vapour out of the leaf slows down if the leaf is already surrounded by moist air.
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