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Respond to changes in the environment
Regulate growth
Regulate reproduction and flowering
Regulate water loss
Regulate growth by controlling mitosis and
cell division
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Undifferentiated tissues that become many
different types of tissues
Located where plants exhibit major growth
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Primary Growth
◦ Growth from the tip of the plant
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Secondary Growth
◦ Growth in the thickness of stems or roots
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Apical Meristems
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Located at the top and the root of plants
Allows for growth of new leaves and flowers
Allows roots to grow down into the soil
Primary growth
Lateral Meristems
◦ Responsible for secondary growth in woody plants
◦ Allows them to increase stem and root thickness
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A directional movement in plants in response
to a stimulus
Type of Tropism
Response
Phototropism
Response to light
Gravitropism
Response to gravity
Thigmotropism
Response to touch
Thermotropism
Response to temperature
Chemotropism
Response to chemical substance
Hydrotropism
Response to water
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Responsible for phototropism
Affects cells on the dark side of the plant
◦ auxin efflux from light side to dark side
◦ causes the cells to elongate
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When light shines directly down on a plant
shoot auxin is equally distributed this causes
the plant to grow straight
Also responsible for gravitropism
◦ auxin causes roots to grow downward into the soil
Stem:
Auxin causes
growth
Root:
Auxin inhibits
growth