Botany Final Flower and fruits , Pollination syndromes and Plant behavior

At the cave in Iraq discussed in the chapter introduction, evidence of six species of medically important flowering plants were found at the burial site of an adult male. What was the evidence?

a. leaf remains
b. pollen in the soil
c. dried plants in a container
d. root portions in the soil

pollen in the soil

Which characteristic is not typical of flowering plants?

a. They have well-developed vascular systems.
b. They have larger leaves with more than one vein.
c. They produce one type of spore.
d. They usually lack roots.

They usually lack roots.

The results of double fertilization are

a. a zygote and endosperm.
b. a zygote and seed coat.
c. an egg cell and endosperm.
d. an egg cell and calyptra.

a zygote and endosperm.

If you genetically modified a plant to produce seeds in which the embryo had no cotyledons, what would you predict as the outcome?

a. The embryo would probably die of malnutrition.
b. The embryo would grow well by putting all its resources into leaf formation.
c. The embryo would live but only produce malformed leaves.
d. There would be no effect on plant growth

The embryo would probably die of malnutrition.

Recent molecular evidence shows that the angiosperms

a. are composed of totally unrelated groups.
b. are divided into two groups, monocots and dicots.
c. are entirely monophyletic.
d. have several distinct lineages.

have several distinct lineages.

Flowers are typically composed of

a. petals, sepals, carpels, stamens.
b. petals, calyx, carpels, stamens.
c. corolla, sepals, ovary, stamens.
d. All the above answers are correct.

All the above answers are correct.

Stamens function in

a. pollen reception.
b. pollen production and release.
c. pollen tube formation.
d. pollen collection.

pollen production and release.

Stigma, style, and ovary are sometimes referred to collectively as

a. androecium
b. calyx
c. pistil
d. integument

pistil

You find a species of tree bearing flowers that are composed of sepals, petals, and stamens. How would you describe this plant?

a. dioecious with imperfect flowers
b. monoecious with perfect flowers
c. monoecious with imperfect flowers
d. dioecious with perfect flowers

dioecious with imperfect flowers

If you examine an orchid flower from bottom to top, you will encounter a peduncle, an ovary, three sepals, three petals (one of which is much larger than the others), and a stamen. How would you describe this flower?

a. perfect, radially symmetric, with an inferior ovary
b. perfect, radially symmetric, with a superior ovary
c. imperfect, bilaterally symmetric, with a superior ovary
d. perfect, bilaterally symmetric, with an inferior ovary

perfect, bilaterally symmetric, with an inferior ovary

Whether flowers are solitary or grouped into inflorescences reflects adaptation to

a. soil moisture.
b. pollination mechanism.
c. endosperm type.
d. presence of calyx and corolla.

pollination mechanism

Often members of the Asteraceae have ray flowers that are sterile but have a bilaterally symmetric corolla with a strap-shaped extension. What function might these flowers have?

a. pollen reception
b. pollinator attraction
c. deterring predation
d. causing the inflorescence to move in the wind

pollinator attraction

The fact that shoot apical meristems convert from a vegetative state to a floral state is a reflection of

a. flowers having evolved from compressed fertile axes.
b. flowers having evolved from a complex branching system.
c. flowers being derived from a single leaf.
d. flowers having an origin in several independent groups.

flowers having evolved from compressed fertile axes.

You are genetically modifying roses to produce plants that have sepals, petals, and carpels but no stamens. You know that Class B genes control stamen development, so you produce plants that have Class B genes knocked out. Which flower parts would you expect in the resulting plants?

a. petals and carpels
b. sepals, petals, and carpels
c. sepals, petals, stamens, and carpels
d. sepals and carpels

sepals and carpels

Because angiosperms produce microspores and megaspores they are called

a. homosporous
b. bicarpic
c. heterosporous
d. bipolar

heterosporous

What is the function of the pollen tube?

a. to carry two sperm nuclei to the stigma
b. to carry two sperm nuclei to the ovule
c. to carry a single sperm nucleus to the ovule
d. to protect the sperm nuclei from the harsh stylar environment

to carry two sperm nuclei to the ovule

The process in angiosperms where a sperm nucleus fuses with an egg cell and the other fuses with polar nuclei is called

a. double fertilization.
b. double pollination.
c. triple fusion.
d. triploid fertilization.

double fertilization.

You treat a typical self-compatible angiosperm with a chemical that disrupts meiosis and the plant produces 2N pollen. If the plant pollinates itself, what would you expect as the ploidy of the endosperm?

a. 6N
b. 5N
c. 4N
d. 3N

4N

What is the mechanism by which diplospory acts?

a. Mitosis fails resulting in a diploid egg and diploid polar nuclei.
b. Meiosis fails resulting in a diploid egg and diploid polar nuclei.
c. Meiosis occurs twice resulting in a diploid egg and diploid polar nuclei.
d. Meiosis fails resulting in a haploid egg and diploid polar nuclei.

Meiosis fails resulting in a diploid egg and diploid polar nuclei.

Dandelions are aggressive weeds largely because they are apomictic. Why?

a. They reproduce vegetatively.
b. They have lost the ability to reproduce sexually.
c. They can maintain hybrid vigor.
d. They can produce large numbers of seeds without relying on pollinators.

They can produce large numbers of seeds without relying on pollinators.

The diploid zygote undergoes mitosis to form

a. a suspensor.
b. primary endosperm nuclei.
c. a multicellular embryo.
d. a unicellular embryo.

a multicellular embryo.

Plant embryos go through several developmental stages during which

a. cotyledons form.
b. root and shoot apical meristems form.
c. primary meristems form.
d. all of the above

all of the above

Though the suspensor is absent at seed maturity, it is important during embryo development because

a. it provides the first cells of the shoot apex.
b. it organizes primary meristem delimitation.
c. it transfers nutrition to the developing embryo.
d. it produces secondary compounds that protect the embryo

it transfers nutrition to the developing embryo.

Why do seeds lose so much water at maturity?

a. Because the parent plant retrieves excess water.
b. Because the stalk connecting the ovule to the ovary wall is separated.
c. Because the parent plant dies just before the seeds mature.
d. Because fruits are shed before seeds mature.

Because the stalk connecting the ovule to the ovary wall is separated.

Which of the following structures do monocot and dicot embryos have in common?

a. radicle
b. scutellum
c. coleoptile
d. coleorhiza

Radicle

An accessory fruit is

a. an immature ovary with included floral parts.
b. a mature ovary.
c. a mature ovary with included floral parts.
d. fused petals and sepals.

a mature ovary with included floral parts.

You examine a microscope slide that has a section of a mature ovary composed of several fused carpels. You would classify the fruit as

a. multiple
b. simple
c. accessory
d. aggregate

simple

Hesperidiums, drupes, and pepos are examples of

a. dry, indehiscent fruits.
b. fleshy, indehiscent fruits.
c. fleshy, dehiscent fruits.
d. dry, dehiscent fruits.

fleshy, indehiscent fruits.

You are at a party where your friend is serving a bowl of “nuts.” You suspect that they are not nuts in the botanical sense. Which characteristics would allow you to determine their true nature?

a. dry versus fleshy
b. splitting along one versus two seams
c. dehiscent versus indehiscent
d. answers A and C

answers A and C

How could you determine whether a fruit is multiple or aggregate?

a. Look for a single versus multiple sets of petals and sepals.
b. Look for many carpels.
c. Look for the arrangement of carpels on the receptacle.
d. Measure the size of the carpels.

Look for the arrangement of carpels on the receptacle.

Why is germination immediately following dispersal rare in seeds from temperate regions?

a. Temperate seeds do not germinate until they have been exposed to warm temperatures.
b. Most seeds are dispersed at the end of the summer, just before it starts to get cold.
c. Temperate seeds take a long time to desiccate completely after dispersal.
d. There is no need for immediate germination because there is little competition for water and sunlight.

Most seeds are dispersed at the end of the summer, just before it starts to get cold.

What are the most important environmental factors influencing seed germination?

a. temperature, light, and water
b. temperature, water, and oxygen
c. light, water, and oxygen
d. oxygen, CO2, and light

temperature, water, and oxygen

Why do you think that the root is the first structure to emerge from the germinating seed?

a. Water is necessary to rehydrate the seed and reactivate the biochemical pathways for growth.
b. The stem and leaves are still absorbing nutrients from the endosperm.
c. It is the simplest organ and the least necessary.
d. It is the organ nearest the opening in the seed coat.

Water is necessary to rehydrate the seed and reactivate the biochemical pathways for growth.

Shoot tips are protected from abrasion during germination by the formation of a hook in the stem to draw the tip through the soil rather than pushing it. Why don’t roots grow in a similar way to protect the delicate root tips?

a. Plants produce many roots, and when the tip of one is abraded away, there are many others to take its place.
b. Root tips are tougher since they constantly push through soil.
c. Root tips are protected by the root

Root tips are protected by the root

What is meant by the term “hypogeous” when referring to seed germination?

a. The roots grow down toward the center of the Earth during germination.
b. The cotyledons remain buried in the soil during germination.
c. No matter which way a seed is oriented in the ground, the roots will always grow down.
d. The seed must be buried deeply for germination to occur

The cotyledons remain buried in the soil during germination.

Coevolution is defined as an interaction between two species that have influenced the evolution of both partners. True /False

True

True or false: Coevolutionary relationships are always beneficial.

a. True, but they are only beneficial to the plants.

b. True, if they weren’t beneficial they would cease to exist.

c. False, sometimes these relationships involve pathogenesis or deceit.

d. False, nearly always these relationships are harmful to the plants.

False, sometimes these relationships involve pathogenesis or deceit.

Which is the reward that mulberry trees (which is my research plant) provide their dispersal agents?

a. fiber-rich leaves

b. sugar-rich fruit

c. protein-rich fruit

d. lipid-rich nuts

sugar-rich fruit

Which of the following is not a reason that understanding pollination is important to global ecology?

a. to maintain high global biodiversity

b. to preserve endangered plants and animals

c. to make more land available for farming

d. to aid in damaged habitat restoration

c. to make more land available for farming

A plant lives in a remote valley. It reproduces only sexually by being pollinated only by one specific butterfly. Also living in the valley is a bird that eats only the fruit of the plant and the butterflies which pollinate it. Extinction of which of these three species would cause the extinction of the other two?

a. the butterfly

b. the plant

c. the bird

d. not enough information

The plant

Pollination is defined as

a. the production of pollen within the anther.

b. the release of pollen from the anther.

c. the transfer of pollen from anther to stigma.

d. the transfer of a sperm cell to an egg cell.

The transfer of pollen from anther to stigma.

How can cross-pollination be possible within a species?

a. Since outbreeding is undesirable, cross-pollination is not necessary.

b. For cross-pollination you only need to transfer pollen from one flower to another on the same plant.

c. For cross-pollination you only need to have pollen transferred from one individual to another.

d. Cross-pollination is not possible within a species.

For cross-pollination you only need to have pollen transferred from one individual to another.

Why is outbreeding advantageous?

a. The number of deleterious genes in the progeny is lower.

b. Genetic variability is reduced.

c. Makes the progeny more fit to live in a stable environment.

d. none of the above

The number of deleterious genes in the progeny is lower.

Which of the following is an advantage of using animals as pollinators?

a. There is a high degree of pollinator specificity.

b. They are energetically more efficient because they don’t have to produce so much pollen.

c. Because animals are more adaptable than plants, they tend not to go extinct as often.

d. none of the above

They are energetically more efficient because they don’t have to produce so much pollen.

Do plants benefit from having species with similar flowers and pollinator rewards nearby?

a. No, since plant-pollinator relationships are so specific that each species is only pollinated by one species of pollinator.

b. No, because this will create competition among the plant species.

c. Yes, because this will attract other types of pollinators to the area.

d. Yes, if the other species flower at different times.

Yes, if the other species flower at different times.

Why would some plants try to prevent small insects from entering their flowers?

a. Small insects cannot fly as far as large ones and are not effective pollinators.

b. These insects would be too small to effect pollination and would simply steal the nectar.

c. Small insects are often eaten by predators before completing pollination; large insects are more successful.

d. Some pollen is too large for small insects to carry, so the pollen would simply be wasted when the insect dropped it.

These insects would be too small to effect pollination and would simply steal the nectar

What is the purpose of a landing platform?

a. It allows the flower to guide the pollinator to the nectar by means of markings or patterns.

b. It allows the pollinator to land on the flower or inflorescence while pollinating it.

c. It gives the pollinator a place to rest; later, the pollinator will remember this flower and return for pollination.

d. answers B and C

It allows the pollinator to land on the flower or inflorescence while pollinating it.

What is the drawback to a flower that is pollinated by an insect with low constancy?

a. The flower might be pollinated by several other species before the proper insect returns.

b. The pollen it brings might be from the day before.

c. The pollen it brings might be from the same flower.

d. The pollen it brings might be from another species

The pollen it brings might be from another species

What flower colors are generally found to attract bees?

a. red, blue, and purple

b. blue, purple, or white

c. white, light brown, light green, and light yellow

d. yellow or red

blue, purple, or white

What type of reward does a bee-pollinated flower usually offer?

a. nectar

b. pollen

c. nectar and pollen

d. no reward

nectar and pollen

Many fly-pollinated flowers have a strong odor of rotting flesh. However, some fly-pollinated flowers produce very little scent. How do they attract pollinators?

a. They produce copious (lots of) nectar.

b. They are the color of rotting meat.

c. They trap other insects to use as bait for flies.

d. They grow near other fly-pollinated plants and flower at the same

They are the color of rotting meat.

What are some of the similarities between butterfly- and moth-pollinated flowers?

a. Both are usually red and open at night.

b. Both are fragrant and have landing platforms.

c. Both supply a nectar reward and open at night.

d. answers A and B

Both are fragrant and have landing platforms.

You work at a retirement center that has room to plant a small garden in the courtyard. You want bright, colorful flowers that have strong, sweet odors and will attract birds, since the residents also enjoy bird-watching. How common will plants that fit all your criteria be?

a. Bird-pollinated flowers tend to open only at night, so you might want to change your criteria to butterfly-pollinated flowers.

b. Bird-pollinated flowers are brightly colored and smell good, so finding some should be easy.

c. Bird-pollinated flowers are not generally bright in color, so they will be hard to find.

d. Bird-pollinated flowers are not generally scented, so they will be hard to find.

Bird-pollinated flowers are not generally scented, so they will be hard to find.

Why are bird-pollinated flowers often tubular in shape?

a. This prevents butterflies from stealing the nectar.

b. Birds require a lot of nectar, which can easily be held in a tube.

c. This traps beetles trying to steal nectar, which act as another food source for the birds.

d. This is the shape of most birds’ heads.

Birds require a lot of nectar, which can easily be held in a tube.

Why are bat-pollinated flowers typically light-colored?

a. to attract bats at night

b. to limit attraction of other pollinators

c. to remain cool during the day’s heat

d. answers 1 and 2

answers 1 and 2

Why are wind-pollinated plants more common allergens for humans than bee-pollinated plants?

a. They are often contaminated with fungal and bacterial spores.

b. They are smaller and lighter weight.

c. They are coated in many different proteins.

d. They produce vast amounts of pollen.

They produce vast amounts of pollen.

Why are there so few plants which are water-pollinated?

a. Water quickly infiltrates the pollen, sinking it to the bottom.

b. It is difficult to produce enough pollen since the water dilutes it so much.

c. Pollen in water quickly rots.

d. Very few flowering plants are aquatic.

Water quickly infiltrates the pollen, sinking it to the bottom.

What benefit does an animal gain from acting as a fruit dispersal agent for a plant such as burdock or Spanish needle, whose fruits cling to fur?

a. The fruits emit mating pheromones.

b. The plant produces a nectar or pollen reward.

c. It can eat some of the fruits.

d. None; this is a commensal relationship (none to one, and benefit to the other).

None; this is a commensal relationship (none to one, and benefit to the other).

Some plants disperse their seeds by attracting animals to eat the fruits. How do you think seeds dispersed in this manner survive the trip through the animal’s digestive system?

a. They have a resistant seed coat.

b. The fruit is not broken down by the animal.

c. The fruit has a hard skin which protects the seeds.

d. They secrete a toxin which acts as an emetic.

They have a resistant seed coat.

What is the similarity between the reward provided to bird pollinators and seed dispersers?

a. Both have a strong scent.

b. The pollen and the seeds are both high in oils.

c. In both cases, plants provide a sweet, high-carbohydrate meal.

d. The plants which are bird-pollinated also have bird-dispersed seeds.

In both cases, plants provide a sweet, high-carbohydrate meal.

Is it correct to say that plants can smell scents the way that people can?

a. No; plants can sense chemical compounds, but they lack a nervous system.

b. Yes; plant sensory systems are similar to those of humans.

c. No; plants cannot smell things since they lack noses.

d. Yes; this is why plants lean toward scented candles.

No; plants can sense chemical compounds, but they lack a nervous system.

Some seeds germinate only in response to butenolide, a compound released during forest fires. What advantage does this confer on these seeds?

a. It doesn’t; these plants would be extinct if scientists did not expose them to butenolide.

b. Heat helps seedlings to grow faster.

c. A fire will decrease the number of plant pathogens in the area.

d. After a fire there will be more nutrients in the soil from the ash and less competition for sunlight from other plants.

After a fire there will be more nutrients in the soil from the ash and less competition for sunlight from other plants.

What is signal transduction?

a. a biochemical pathway that produces hormones

b. a process by which signals are transferred from a response site to a receptor

c. a process by which signals are transferred from a receptor to a response site

d. the travel of a messenger molecule from the cell membrane to the nucleus

a process by which signals are transferred from a receptor to a response site

Plants can rapidly amplify a signal from an activated receptor by

a. heating the cell slightly using heat shock proteins.

b. sending several messenger molecules per receptor.

c. using a combination of animal and plant messengers.

d. using ions as messenging molecules, which carry an electrical charge.

sending several messenger molecules per receptor.

Which of the following is the most accurate description of a plant hormone?

a. a compound that speeds up a reaction or allows it to occur

b. a compound that must be transported via the xylem to a new area to have an effect

c. a compound that is produced in one area of the plant but acts on another

d. a compound found only in plants which affects only the growth and development of other plants

a compound that is produced in one area of the plant but acts on another

Why would a fungus produce a plant hormone?

a. Some fungi require external stimuli, such as plant hormones, to trigger reproduction.

b. If the fungus were in contact with a plant, it could cause specific plant responses that might benefit the fungus, such as excess food production.

c. Plant hormones can affect organisms other than plants.

d. The hormone might be used to disguise the fungus from harmful bacteria.

If the fungus were in contact with a plant, it could cause specific plant responses that might benefit the fungus, such as excess food production.

What role do auxins play in plant growth?

a. induce cell elongation

b. promote formation of new vascular tissue

c. stimulate production of secondary tissues

d. all of the above

all of the above

You want your rose bushes to have many lateral branches, so they will appear as bushy as possible. What can you do to your roses to increase the number of branches?

a. Apply florigen to the entire plant, which will cause the lateral buds to expand.

b. Paint the lateral buds with cytokinins.

c. Remove the leaves on the top third of the plant.

d. Remove the shoot apex to stop the flow of auxin.

Remove the shoot apex to stop the flow of auxin.

How are cytokinins transported about the plant?

a. They travel via the xylem.

b. They travel via the phloem.

c. They diffuse from cell to cell.

d. They are released from the soil and absorbed through the stomata.

They travel via the xylem.

Ethylene can stimulate fruit softening and an increase in carotenoid synthesis. Why would synthesis of carotenoids be advantageous in ripening fruit?

a. This would increase photosynthesis, producing more sugars for the fruit.

b. The fruit would have a higher vitamin A content, making it more desirable to animals.

c. The more noticeable color of the ripened fruit would aid dispersal by animals.

d. A and C

The more noticeable color of the ripened fruit would aid dispersal by animals.

What is the “triple response” of a seedling to ethylene?

a. stem elongation, stem swelling, cotyledon opening

b. inhibition of elongation, stem swelling, hook formation

c. imbibition of water, seed swelling, germination

d. cell specialization, fruit ripening, leaf drop

inhibition of elongation, stem swelling, hook formation

What would happen to a dwarf plant if you sprayed it with gibberellin?

a. It would grow to normal size.

b. It would die if the gibberellin did not break down fast enough into monoterpenes.

c. Its internodes would elongate, causing it to be spindly and weak.

d. Nothing; dwarf plants lack gibberellin receptors.

It would grow to normal size.

GA is similar to what other hormone?

a. auxin, because both cause apical dominance

b. cytokinin, because both stimulate cell division

c. ethylene, because both are gases

d. abscisic acid, because both cause abscission of leaves and fruits

cytokinin, because both stimulate cell division

Which hormone is responsible for the formation of protective bud scales on perennial plants?

a. cytokinin

b. gibberellin

c. abscisic acid

d. jasmonic acid

abscisic acid

In what kinds of plants can you find brassinosteroids?

a. They are found in all types of plants.

b. They are only found in flowering plants.

c. They are found in plants which produce secondary growth.

d. They are only found in members of the Brassicaceae, the mustards.

They are found in all types of plants.

Which of the following act to mobilize plant defenses against pathogens?

a. salicylic acid

b. brassinosteroids

c. systemin

d. A and C

A and C

Sugars have many functions in plants. Can they act as hormones?

a. No, they are produced in too much abundance.

b. No, hormones must be transported via the xylem, and sugars move via the phloem.

c. Yes, they regulate amounts of chlorophyll during photosynthesis.

d. Yes, they slow stomatal closure in hot, sunny weather.

Yes, they regulate amounts of chlorophyll during photosynthesis.

Why did Native Americans chew willow or aspen bark to relieve toothaches?

a. These trees produce precursors to salicylic acid, a pain reliever.

b. Bark from these trees contains numbing agents.

c. These plants are high in antibacterial compounds.

d. The bark is tough and non-poisonous, but otherwise merely acts as a placebo.

These trees produce precursors to salicylic acid, a pain reliever.

What is the most logical reason that a seed would only germinate if it sensed it was in the light?

a. There are no herbivores nearby.

b. Competing plants are far enough away that there would be sufficient resources for it.

c. Soil harbors pathogens, so seeds don’t germinate underground.

d. The seed has a chemical imbalance.

Competing plants are far enough away that there would be sufficient resources for it.

You have a houseplant on a table near a window, and you notice that it is leaning toward the window. What molecule is responsible for the plant’s ability to sense the direction of the light?

a. chlorophyll

b. zeaxanthin

c. auxin

d. phytochrome

phytochrome

Phytochrome is present in many types of plants, and is also found in some algae and bacteria. What is the most likely explanation for this?

a. The use of phytochrome arose early in evolutionary history.

b. Many types of organisms have evolved to use the same light-sensing compounds.

c. Phytochrome is less efficient than cytochrome, which arose more recently.

d. Phytochrome has many uses, so it is understandable that many types of organisms would use it.

The use of phytochrome arose early in evolutionary history.

Aster, rice, poinsettia, and gardenia are short-day plants. What triggers flowering in these plants?

a. dark periods that are shorter than a certain amount

b. dark periods that are longer than a certain amount

c. light periods that are shorter than a certain amount

d. light periods that are longer than a certain amount

dark periods that are longer than a certain amount

You have a group of plants which flower in early summer, when nights are the shortest. How would you determine if any of these plants are day-neutral?

a. Put them under 24-hour lights.

b. Increase the amount of darkness and see which ones still flower.

c. Check on the plants at night to see if their flowers are open.

d. Spray the plants with auxin; the ones that keep their flowers are day-neutral.

Increase the amount of darkness and see which ones still flower.

Why do short-day plants like dahlias and strawberries rarely occur naturally in the tropics?

a. Short-day plants are generally found only at high altitudes, where the days are shortest.

b. The sunlight is too intense near the equator.

c. The temperatures are too hot during the day.

d. The nights are not long enough there.

The nights are not long enough there.

Plants will photosynthesize most efficiently if their leaves are all receiving adequate sunlight. In large trees, this is a difficult task. How do plants attempt to minimize the shading of their leaves?

a. Shaded leaves contain more inactivated phytochrome, which suppresses internodal elongation of stems.

b. Shaded leaves contain more activated phytochrome, which suppresses internodal elongation of stems.

c. Shaded leaves contain more inactivated phytochrome, which encourages internodal elongation of stems.

d. Shaded leaves contain more activated phytochrome, which encourages internodal elongation of stems.

Shaded leaves contain more inactivated phytochrome, which encourages internodal elongation of stems.

Most stems grow upward, against the force of gravity. How are roots sensitive to gravity?

a. They grow downward, toward the force of gravity.

b. They also grow upward, against the force of gravity.

c. They are not; they grow away from light.

d. Roots exhibit a weak response to gravity, growing slightly downward.

They grow downward, toward the force of gravity.

Pea and bean plants use their tendrils to help support the main stem. The tendril wraps around a support and holds the main stem upright. This is an example of what type of response?

a. negative gravitropism

b. positive gravitropism

c. thigmotropism

d. chemotropism

thigmotropism

How can roots growing in waterlogged soil use aerenchyma to remain alive?

a. The large air spaces in the aerenchyma allow diffusion of oxygen from above-ground portions of the plant to the roots.

b. The air trapped in the aerenchyma adds to the buoyancy of the roots.

c. Water which enters the roots can be pumped out via the aerenchyma.

d. Carbon dioxide building up in the roots can be diffused upward into the above-ground portions of the plant.

The large air spaces in the aerenchyma allow diffusion of oxygen from above-ground portions of the plant to the roots.

What is the function of heat shock proteins in plants?

a. They flush toxins generated by high temperatures from the cells.

b. They allow plants which have been exposed to sudden high temperatures to recover by closing the stomata.

c. They increase the temperature in the cell to the amount needed to start certain critical reactions.

d. They wrap around important proteins to prevent them from coagulating in high temperatures.

They wrap around important proteins to prevent them from coagulating in high temperatures.

If you want to grow daffodils in Florida, you must keep the bulbs in the refrigerator for several weeks before planting them. Why?

a. Daffodil bulbs need to be cold when they are planted; this is why they are planted in the fall in the Midwest.

b. Daffodils need a vernalization period before they will flower.

c. The cold temperatures reduce the susceptibility to disease when planted.

d. The refrigerator mimics the photoperiod found in their native habitat.

Daffodils need a vernalization period before they will flower.

Would a hypersensitive response occur if a plant with a dominant resistance gene was attacked by a pathogen?

a. Yes, if the pathogen carried a dominant avirulence gene.

b. Yes, if the pathogen were susceptible to the resistance gene.

c. No, because the plant’s resistance gene is dominant over that of the pathogen.

d. This would only occur if the plant had been attacked before by this same strain of pathogen.

Yes, if the pathogen carried a dominant avirulence gene.