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13 Cards in this Set
- Front
- Back
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Phototropism process |
1. 450 nm light illuminates plant 2. Photoreceptors receive, react, and initiate response 3. Phototropins receive blue light 4. Auxin moves to darker side 5. Auxin releases H+, which decreases pH, activates expansin, and causes cells to swell |
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Darwin experiment process and conclusions |
Placed opaque cover over tip, no phototropism 1. Stimulus detected at tip 2. Response carried out at another location |
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Boysen-Jensen experiment process and conclusions |
Phototropism did not occur when 1. Tip replaced by opaque gelatin cap 2. Tip cut off 3. Tip separated by mica Signal is chemical passing down |
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Etiolation purpose and characteristics |
Increases the chance plant will access light 1. Elongated internodes 2. Pale coloration 3. Small leaves 4. Will die when seed reserves exhausted |
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Gravitropism process |
1. Statoliths send gravity signal to PIN proteins 2. PIN proteins accumulate in underside 3. Top of root elongates 4. Root grows downward |
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Statoliths description |
Organelles containing grains Amyloplasts: plastids that function in starch storage |
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PIN proteins description |
Secondary transporters of auxin (IAA) Use polar transport: directional movement |
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Auxin concentrations [1] to [2] stem growth [3] root growth |
High enough Stimulate Inhibit |
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Characteristics and examples of nastic movements (5) |
Growth-independent Immediate Nondirectional Caused by turgor Makahiya, stomata opening |
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Ethylene role and effects |
Induces senescence 1. Flowering: wilting 2. Fruit development: breaks down cell wall, turns starches and acids to sugars in a positive feedback mechanism 3. Abscission: triggers programmed cell death in leaves and fruits when auxin levels decline |
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Gibberellins synthesis and effects |
Made in apical meristems and developing seeds 1. Germination 2. Growth to maturity: stem elongation 3. Flowering: flower bolts, producing stem 4. Fruit development |
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Abscisic acid effects (ABA) |
1. Abscission: slows growth, stimulates closing of stomata through K+ transport out of guard cells 2. Seed dormancy: high initial concentration, seed will only germinate under optimal conditions, after ABA has been inactivated or leached out |
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Cytokinins synthesis and effects |
Made in roots and travels upwards 1. Growth to maturity: stimulates activation of axillary (terminal) buds 2. Flowering 3. Fruit development |
