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15 Cards in this Set
- Front
- Back
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What is water potential?
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Potential energy of water in a particular environment compared with potential energy of pure water at atmospheric pressure at the same temperature. Water moves from areas of high water potential to areas of lower water potential
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What is the pressure-flow hypothesis?
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events at source tissues and at sink tissues create a steep pressure potential gradient in phloem
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Is sugar movement unidirectional?
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yes
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What are sinks? How can they change during the course of a plant’s life?
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Sink: tissue where sugar exits the phloem (Has low concentration of sugar). during the growing season, sugar use high and production is low. early growing season: newly developing leaves
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What is translocation? What are sources?
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Translocation: the movement of sugars from source to sink, sources are tissues where sugar enters the phloem (has high concentration of sugar). during the growing season, mature leaves and stems. early growing season: storage cells in roots
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Does water transport require energy? Is it unidirectional or bidirectional?
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ijuoijuoi
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What is the cohesion-tension theory?
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waater movement upward through plant vascular tissues is due to transpiration, which pulls a cohesive column of water upward
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How do surface tension, cohesion, adhesion influence water movement in plants?
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surface tension is the pull on water molecules at air-water interface. Cohesion is Mutual attraction among like molecules, hydrogen bonding. Adhesion is attraction of unlike molecules, h bonds btw h2o and cell walls of tracheids and vessel elements.
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What is transpiration?
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water loss from aboveground plant parts. occurs primarily through stomata
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What is bulk flow and when will it occur?
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the directional movement of a substantial volume of fluid due to pressure differences, such as movement of water through plant phloem. occurs when there is no membrane in response to pressure differences
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What is osmosis?
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osmosis is the diffusion of water across a selectively permeable membrane across a concentration gradient.
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Turgor pressure?
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the outward pressure exerted by the fluid contents of a plant cell against its cell wall
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What is pressure potential?
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Any kind of physical pressure on water. PE of water caused by pressure differences. equal to the sum of all types of pressure that affect water, such as atmospheric pressure, wall pressure, and tension
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What is solute potential?
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the potential energy of water caused by a difference in solute concentrations at two locations.
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What are the two components to water potential?
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Solute potential and pressure potential
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