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  1. photomorphogenesis
    effects of light on plant morphology
  2. plants detect what 3 things
    • light direction
    • intensity
    • wavelength
  3. action spectrum
    depicts relative response of a process to different wavelengths (graph)
  4. blue-light photoreceptors
    • -control hypocotyl elongation
    • -control stomatal opening
    • -control phototropism
  5. phytochromes
    • -pigments that regulate many of a plant's responses to light throughout its life
    • -seed germination
    • -shade avoidance
  6. Image Upload find:

    Two identical subunits
    photoreceptor activity
    kinase activity
    • -what those are
    • -blue part
    • -upper part
    • -ball part
  7. the photochrome system provides the plant with info about what
    • the quality of light
    • -shaded plants receive more far-red than red light
  8. shade avoidance response
    the phytochrome ratio shifts in favor of Pr when a tree is shaded
  9. circadian rhythms 
    • •Cycles that are about 24 hours long and are governed by an internal “clock”
    • •Can be entrained to exactly 24 hours by the day/night cycle
    • •The clock may depend on synthesis of a protein regulated through feedback control and may be common to all eukaryotes
  10. phytochrome conversion marks what
    sunrise and sunset providing the biological clock with environmental cues
  11. photoperiod
    the relative lengths of night and day, is the environmental stimulus plants use most often to detect the time of year
  12. photoperiodism
    a physiological response to photoperiod
  13. Short-day plants
    –Flower when light period is shorter than a critical threshold
  14. long-day plants
    –Flower when a light period is longer than a certain number of hours
  15. day-neutral plants
    –Flowering is controlled by plant maturity, not photoperiod
  16. short-day plants are governed by whether the?
    critical night length sets a minimum number of hours of darkness
  17. long-day plants are governed by whether the?
    critical night length sets a maximum number of hours of darkness
  18. Flowering Locus C (FLC)
    • –Discovered in Arabidopsis thaliana
    • –FLC activation inhibits flowering
    • –MADS box gene
    • –Controls vernalization
    • –Epigenetic control regulates the gene
    • •Cold exposure reduces expression
  19. Florigen
    the flowering signal 
  20. gravitropism
    • response to gravity
    • -roots show positive gravitropism
    • -shoots show negative
  21. statoliths
    • –specialized plastids containing dense starch grains
    • •Some mutants that lack statoliths are still capable of gravitropism
    • •Dense organelles, in addition to starch granules, may contribute to gravity detection
  22. thigmomorphogenesis
    refers to changes in form that result from mechanical disturbance
  23. 5 responses to drought
    • Reduce transpiration by closing stomata
    • •Slow leaf growth
    • •Reduce exposed surface area
    • •Growth of shallow roots is inhibited
    • •Deeper roots continue to grow
  24. Response to flooding
    •Enzymatic destruction of root cortex cells creates air tubes that help plants survive oxygen deprivation during flooding
  25. 3 responses to herbivory
    • •Plants use defense systems to deter herbivory, prevent infection, and combat pathogens
    • •Plants counter excessive herbivory with physical defenses such as thorns and chemical defenses such as distasteful or toxic compounds
    • •Some plants even “recruit” predatory animals that help defend against specific herbivores
  26. Secondary Chemicals can be
    Bitter, poisonous, cause diarrhea, interfere in the Citric acid cycle, intoxication and other harmful effects
  27. the 3 classes of secondary chemicals are
    • –Nitrogen compounds (e.g. strychnine, morphine)
    • –Terpenoids (citronella, menthol, camphor)
    • –Phenolics (cannabinoids, lignin)
  28. plants damaged by insects can release what
    volatile chemicals to warn other plants of the same species
  29. Methyljasmonic acid can activate?
    expression of genes involved in plant defenses
Card Set:
2013-03-11 22:10:08

Test 2
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