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90 Cards in this Set
- Front
- Back
What controls the site productivity?What is the major factor influencing plant growth and distribution?
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the amount of available water;
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Which slopes get more direct solar radiation, what type of soil do they have and what type of trees grow on them usually?
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south, southwest, dryer and warmer, pines usually only grow, very little production here
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What does water have an influence on?
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cell division and stem elongation
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What is the largest component of plants, how much of it makes up growing tissue and how much of it makes up woody plants?
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water, 80-90%, 45-60%
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What does water serve as?
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a solvent which transports minerals and dissolved carbohydrates throughout the plant
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What are some of the functions of water?
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used for turgidity, dissolves a great many chemical substances, reactant in chemical reactions, serves in photosynthesis for source of electrons
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What is turgidity?
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serves for pressure in plants, necessary for cell enlargement, growth and even maintenance of form in some plants
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What is water potential?
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movement of water from cell to cell in plants, measure of free energy of water
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What is the conversion of a megapascal?
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10 bars
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What makes up water potential?
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turgor potential and osmotic potential
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What is osmotic potential due to?
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dissolved solutes in the water,(sugar and salt), the more dissolved solutes the lower the osmotic potential
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When you see wilted leaves, whats wrong with the water potential?
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the turgor potential is at zero
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What happened to the water potential when there is dead xylem in trees?
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negative turgor pressure, "under tension"
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What are auxins?
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play major role in cell elongation and tropisms
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What is development?
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Differentiation of cells into the various tissues and organs.
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What is growth?
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Refers to an increase in size by cell division and enlargement.
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What is osmotic adjustment?
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An acclimation where the plant lowers its osmotic potential in response to a drought and in this way maintains turgor despite lower water potential.
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What is dessication tolerators?
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The ability of plants to still dessicate but still survive
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What is dessication postponement?
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Decrease water loss, or increase water uptake,
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What are drought tolerators?
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Have portions during their active life cycle during periods which drought can be expected.
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What are drought avoiders?
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Plants that complete their entire life cycles before a drought occurs
Ex. Desert species |
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What are four mechanisms for a drought?
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Drought tolerator, avoider, dessication postponement and tolerator
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What is acclimation?
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A modification of a characteristic in response to the environment
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What is adaptation?
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Characteristics which are heritable or passed on from generation to generation.
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What are two drought mechanisms?
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Adaptation and acclimation
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What is a drought?
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A meteorological event which can be defined as a period without rainfall of sufficient duration that plant growth is impacted negatively.
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What is a tensiometer?
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Used to measure the water potential of soil
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What is the pressure chamber used for?
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To measure the water potential in the xylem of woody plants.
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What are auxins?
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play major role in cell elongation and tropisms
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What is development?
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Differentiation of cells into the various tissues and organs.
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What is growth?
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Refers to an increase in size by cell division and enlargement.
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What is osmotic adjustment?
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An acclimation where the plant lowers its osmotic potential in response to a drought and in this way maintains turgor despite lower water potential.
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What is dessication tolerators?
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The ability of plants to still dessicate but still survive
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What is dessication postponement?
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Decrease water loss, or increase water uptake,
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What are drought tolerators?
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Have portions during their active life cycle during periods which drought can be expected.
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What are drought avoiders?
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Plants that complete their entire life cycles before a drought occurs
Ex. Desert species |
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What are four mechanisms for a drought?
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Drought tolerator, avoider, dessication postponement and tolerator
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What is acclimation?
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A modification of a characteristic in response to the environment
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What is adaptation?
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Characteristics which are heritable or passed on from generation to generation.
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What are two drought mechanisms?
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Adaptation and acclimation
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What is a drought?
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A meteorological event which can be defined as a period without rainfall of sufficient duration that plant growth is impacted negatively.
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What is a tensiometer?
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Used to measure the water potential of soil
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What is the pressure chamber used for?
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To measure the water potential in the xylem of woody plants.
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Which has more water potential; pure water or a solution?
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Pure water
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In which direction does water move?
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High to low regions of water potential
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What are selectively permeable membranes?
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All the free movement of water to pass through, but not solutes to pass through the membrane of cells
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What makes it so that the turgor pressure doesn’t cause the cell’s membrane to rupture?
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Rigid cell walls
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What is the cohesion-tension theory?
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The way that water gets up to the top of trees; the act of the water being “pulled up” by the act of transpiration (evaporation).
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What are auxins?
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Produced in growing tips, signal response responsible for curvature.
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What are tropisms?
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Movement in plants in response to unidirectional signals
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What do auxins play a role in?
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Apical dominance-the tip inhibits the growth of lateral buds
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What does auxin do to dormant buds?
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Keeps the buds from sprouting
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What happens to stems when they are exposed to a lot of light?
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The auxin breaks down, allowing dormant buds to sproud into epicormic sprouts.
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What is phototropism? How is auxin involved?
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Bending towards the light, auxin is on the shaded side causing more curvature towards the light
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What is gravitropism?
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Movement in response to gravity
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What happens to roots when the shoot is dipped in auxin?
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They grow more quickly
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What is parthenocarpic fruit?
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Seedless fruit;growth without fertilization; b/c of auxin
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What are gibberellins?
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Large group of chemical compounds, stem elongation
Longer days; elongation of plants (bolt) Flower formation and fruit development |
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What are “anit-gibberellins used for?
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Power lines-instead of so many top clippings, and for greenhouse growth purposes
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What are cytokinins?
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produced in meristematic regions, called zeatin, cell division and cell and organ enlargement, promote lateral bud development
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What are cytokinins used for?
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on the fascicular buds of christmas trees, to promote growth
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What type of trees are cytokinins applied to?
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christmas trees, and fraser firs
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What is etylene?
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gas produced by ripening fruit, also produced in combustion reactions, causes abscission, causes fruit ripening
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What is abscission?
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shedding of a plant part, occurs in plants once auxin levels decrease later in the growing season, cells slowly break down creating a line where the shedding occurs
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What is abscisic acid?
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seed dormancy, induce a resting bud, inhibits seed germination and furthers dormancy, signal of stomata closure,
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Which growth regulator causes the witches broom?
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cytokinin
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Which growth regulator is directly related to broadleaf weed killer?
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auxin
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Which growth regulator is related to seedling vigor during storage?
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ethylene
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Which growth regulator is related to stem/internode elongation?
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gibberellin
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Which growth regulator is related to stomatal closure?
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ABA
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Which growth regulator is related to rotting fruit?
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ethylene
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Which growth regulator is related to the crazy rice disease?
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gibberellin
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Which growth regulator is related to cell division?
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cytokinin
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What is a condition in which helps temperate woody trees survive harsh winter periods?
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dormancy
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When are trees generally in cold hardy?
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when they are deep in dormancy
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What is dormancy in shoots?
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period of ceased growth and a resting bud that is enclosed in scales.
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When will true dormancy be broken?
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when adequate chilling has occured
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What is quiescence?
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a resting state in response to adverse environmental conditions
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What are the stages of dormancy and describe each?
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pre-dormancy-reversible of favorable growing conditions take place
true dormancy- non-reversible- only if there is a period of sustained chilling will it break post-dormancy-bud is still capable of growing but supressed by adverse environmental conditions |
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What is the main environmental signal that triggers the onset of dormancy?
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short Daylength, long nights short days
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What happens when daylength changes?
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growth regulators are produced, abscisic acid-builds up during fall
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When are the best environmental conditions for a plant to enter true dormancy?
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cool temperatures and short days
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How does water and nutrition effect dormancy?
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if the plant is water stressed then it will promote dormancy, if there is high nutrition it will delay dormancy
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What conditions help a plant enter post-dormancy?
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between the degrees of 2-4 degrees celcius, and with chilling
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What does chilling do to ABA?
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breaks it down
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What is a way that dormant trees survive freezing temps?
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cold hardiness
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What are frost cracks?
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when the pressure from the expanding ice exceeds the strength of the wood
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What do temperate trees do to prevent freezing in living tissues as part of the mechanisms of cold hardiness?
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deep supercooling, intracellular dehydration
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What is deep supercooling?
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maintaining water in cells in a liquid state below 0 degrees but above nucleation state
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What is intracellular dehydration?
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plants can survive at temps. below 40 degrees celsius, but the extracellular spaces are the only liquids that will freeze b/c the liquid is pulled out of the cells, just causing damage from dehydration
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