Term
| what is the inactive form of phytochrome? what color? |
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Definition
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Term
| what is the active form of phytochrome? what color? |
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Definition
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Term
| what is the wavelength of far red light? |
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Definition
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Term
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Definition
| the natural conversion of Pfr back to Pr |
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Term
| what is the response to Pr? |
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Definition
1.inhibits seed germination
2. etiolation
3. no flowering |
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Term
| what is the response to Pfr? |
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Definition
1. seed germination
2. normal growth
3. no flowering |
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Term
where is Type I phytochrome common?
Type II? |
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Definition
Type I - etiolated seedlings
Type II - green plants and seeds |
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Term
| what is the Type I Pr maximum? Pfr? |
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Definition
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Term
| what is the Type II Pr maximum? Pfr? |
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Definition
Type II:Pr 645-667
Pfr 724 |
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Term
| what is the structure of phytochrome? |
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Definition
| protein (polypeptide) with attached chromophore |
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Term
| how do Pr an Pfr differ structurally? |
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Definition
| are cis-trans isomers of each other |
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Term
| T/F: phytochrome is active in bacteria + fungi |
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Definition
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Term
| what does photodormant mean? |
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Definition
| seeds require light to germinate |
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Term
| what affect does temperature have on phyochrome reactions? |
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Definition
| high temperatures (35C) prevent germination even with light, low tempeartures (10-15C) allow germination without light (lettuce seeds) |
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Term
| why is far red light more abundant on forest floor when canopy present? |
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Definition
| chlorphyll in canopy leaves absorb most of the red light |
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Term
| what area of the seed specifically is light sensitive? |
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Definition
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Term
| what hormones may substititute the light requirement for seed germination in some species? |
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Definition
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Term
| what affects promoted by long days (short nights)? |
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Definition
bolting
rooting of cuttings
vegetative reproduction (runners, etc) |
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Term
| what are the responses of 'The Autumn Syndrome;? |
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Definition
1. leaf abscission
2. reduced stem elongation
3. reduced chlorophyll production
4. increased formation of other pigments
5. dormancy
6. frost hardiness
7. senesence of annuals |
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Term
| what are some factors that may affect the response of a plant to photoperiodism? |
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Definition
1. temperature
2. maturity of plant
3. Florigen
4. hormones |
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Term
| what hormone can replace the long day stimulus but not short day? |
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Definition
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Term
| what is the response to mechanical stress? |
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Definition
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Term
| what is the response to mechanical shaking called? |
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Definition
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Term
| what is the hormone response to mechanical stimulation? |
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Definition
1. increased ethylene levels
2. inhibited auxin transport
3. possibly lower GA levels |
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Term
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Definition
| when an environmental stimulus determines the direction of movement |
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Term
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Definition
| reversable uptake of water into special cells called motor cells |
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Term
| what are the three stages of plant movement? |
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Definition
1. Perception (by receptor, pigment)
2. Transduction - stimulus changed to biochemical/biophysical changes
3. Motor response |
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Term
| what are three nastic movements? |
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Definition
1. Hypnasty
2. Epinasty
3. Nyctinasty
4.Hydronasty
5.Thigmonasty |
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Term
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Definition
| upward bending of an organ |
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Term
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Definition
| downward bending of an organ |
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Term
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Definition
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Term
| what cells involved in opening leaf sleep?movements? |
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Definition
extensor cells on upper surface expand
flexor cells on lower surface shrink |
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Term
| what ions are transferred from extensor to flexor cells when leaves close? |
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Definition
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Term
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Definition
| folding or rolling of leaves due to water stress |
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Term
| what causes thigmonastic response in Mimosa? |
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Definition
| water transport out of motor cells in the pulvini and K+ transfer |
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Term
| In mimosa (thimonastic response), what is the action potential? |
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Definition
| tranmission of ions across cell membranes. cannot move from leaflet to leaflet |
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Term
| In mimosa (thigmonastic response), what is transmitted between leaflets? |
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Definition
| chemical transmission: turgorin transmitted through xylem |
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Term
| what is the chemical transmitted between leaflets in the thimonastic response of mimosa? |
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Definition
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Term
| what may be responsible for venus flytrap trigger response? |
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Definition
| rapid acid growth. protons pumped into lower cells, loosens cell walls which quickly absorb water |
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Term
| what are nastic movements? |
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Definition
| responses to non-directional stimuli |
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Term
| what is the difference between the Cholodny-Went and Blaauw model of photoropism? |
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Definition
Cholodny-Went - auxins migrate away from irradiated side
Blaauw - auxin inhibitors increase on irradiated side |
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Term
| what does leaf mosaics refer to? |
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Definition
| the fact that leafs in a canopy rarely overlap each other |
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Term
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Definition
| the orientation of organs at right angles to the light |
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Term
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Definition
| the orientation of organs at right angles to the light |
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Term
| what controls diaphototropic movement? |
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Definition
| movement of K+ in and out of motor cells |
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Term
| what is Skototropism? where is this common? |
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Definition
growht toward darkness
-allows vines to find trees to climb |
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Term
| what are the three types of gravitropism? |
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Definition
1.Orthogravitropism
2.Diagravitropism
3.Agravitropic |
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Term
| what is the difference between orthogravitropism and diagravitropism? |
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Definition
ortho - vertical growth of stem or root
dia - horoz. growth of stem or root |
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Term
| what does agravitropic mean? |
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Definition
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Term
| where does gravitropic perception take place? |
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Definition
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Term
| what organelle may be involved in gravitropic response? what hormone? |
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Definition
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