plant responses
plant hormones produce their effects by
both a and b -altering the expression of genes - modifying the permeability of the plasma membrane
why might animal hormones function differently from plant hormones
both a and d - animals move rapidly away from negative stimuli, and most plants dont - plants are much more variable in their morphology and development than animals
Buds and sprouts often form on tree stumps. Which of the following hormones would you expect to stimulate their formation?
cytokinins
What does a short-day plant require in order to flower?
a night that is longer than a certain length
If you wanted to genetically engineer a plant to be more resistant to drought, increasing amounts of which of the following hormones might be a good first attempt?
abscisic acid
which of the following statements about plant hormones is false
abscisic acid generally promotes growth
The houseplants in a windowless room with only fluorescent lights begin to grow tall and leggy. Which of the following treatments would promote more normal growth?
add some incandescent bulbs to increase the amount of red light
Plants are affected by an array of pathogens. Which of the following is not a plant defense against disease?
all of the above are plant defenses against disease. -cells near the point of infection destroying themselves to prevent the spread of the infection -production of chemicals to kill pathogens -acquiring gene-for-gene recognition that allots specific proteins to interact so that the plant can produce defense against the pathogen -a waxy cuticle that pathogens have trouble penetrating
ethylene, is an example of a plant hormone, may have multiple effects on a plant, depending on all the following except
altered chemical structure of ethylene from gas to a liquid
the apical bud of a pine tree inhibits the growth of lateral buds through the production of
auxin
plant hormones can have different effects at different concentrations. this explains how
auxin can stimulate cell elongation in apical meristems, yet will inhibit the growth of axillary buds
Plants growing in a partially dark environment will grow toward light in a response called phototropism. Which of the following statements is incorrect regarding phototropism?
auxin causes a decrease in growth on the side of the stem exposed to the light
which of the following has not been established as an aspect of auxins role in cell elongation
auxin increases the quantity of cytoplasm in the cell
Cells elongate in response to auxin. All of the following are part of the acid growth hypothesis except
auxin-activated proton pumps stimulate cell division in meristems
which of the following hormones would be most useful in promoting the rooting of plant cuttings
auxins
which plant hormones might be used to enhance stem elongation and fruit growth
auxins and gibberellins
most plants close their stomata at night. what color of light would be most effective in promoting stomatal opening in the middle of the night
blue
external stimuli would be received most quickly by a plant cell if the receptors for signal transduction were located in the
cell membrane
When growing plants in culture, IAA is used to stimulate cell enlargement. Which plant growth regulator has to now be added to stimulate cell division?
cytokinin
which plant hormone(s) is(are) most close associated with cell division
cytokinin
in general which of the following is not a plant response to herbivores
domestication, so that humans can protect the plant
If you were shipping green bananas to a supermarket thousands of miles away, which of the following chemicals would you want to eliminate from the plants' environment?
ethylene
the plant hormone involved in aging and ripening of fruit is
ethylene
the ripening of fruit and the dropping of leaves and fruit are principally controlled by
ethylene
plant growth regulators can be characterized by all of the following except that they
function independently of other hormones
the synthesis of which of the following hormones would be a logical first choice in an attempt to produce normal growth in mutant dwarf plants
gibberellin
In attempting to make a seed break dormancy, one logically could treat it with
gibberellins
A flash of red light followed by a flash of far-red light given during the middle of the night to a short-day plant will likely
have no effect upon flowering
According to the acid growth hypothesis, auxin works by
increasing wall plasticity and allowing the affected cell walls to elongate
which of the following is not a direct function of either auxin or gibberellin
inducing senescence and ripening
many plants flower in response to day-length cues. which statement concerning flowering is false
long day plants flower in response to long days, not short nights
Auxins (IAA) in plants are known to affect all of the following phenomena except
maintenance of dormancy
a short day plant will flower only when
nights are longer than a certain critical value
incandescent light bulbs, which have high output of red light, are least effective in prommoting
phototrophism
Seed packets give a recommended planting depth for the enclosed seeds. The most likely reason some seeds are to be covered with only 1/4 inch of soil is that the
seeds require light to germinate
Both red and blue light are involved in
stem elongation
which of the following is currently the most powerful method of research on plant hormones
studying mutant plants
Auxin is responsible for all of the following plant growth responses except
the detection of photoperiod
a long day plant will flower if
the duration of continuous darkness is less than a critical length.
most scientists agree that global warming is underway; thus it is important to know how plants respond to heat stress. which of the following is an immediate short-term response of plants to heat stress
the production of heat shock proteins like those of other organisms
Plant cells begin synthesizing large quantities of heat-shock proteins
when the air around the species from temperate regions is above 40C
