Plant Reproduction Test Questions & Answers Chapter 40 12e

Biology, 12e (Raven)

Chapter 40 Plant Reproduction

1) Angiosperms use which temporary reproductive structures that are not present in any other group of plants?

A) cones

B) carpels

C) receptacles

D) flowers

E) seeds

2) What is the process that eventually leads to the death of a plant?

A) outcrossing

B) dichogamy

C) abscission

D) perennial

E) senescence

3) The developmental transition during which plants become able to respond to external and/or internal signals that promote flowering is known as

A) cloning.

B) initiation.

C) abscission.

D) perennial development.

E) phase change.

4) Your friend examines an ivy vine growing on the side of a campus building and says, "Look – some of the branches on this plant have a different morphology. The leaf shapes and patterning are different, and there are flowers on some branches but not others. There must have been a mutation!" You respond,

A) "I think you're right. Maybe there was a mutation in the LEAFY (LFY) gene, and the loss of LFY has promoted flowering and had pleiotropic effects on leaf morphology."

B) "No, those branches have just undergone phase change. Now they're in the adult form, and have become competent to respond to flowering signals."

C) "I think you're right. Maybe the embryonic flower (emf) gene is being overexpressed, and that's causing flowers to form."

D) "No, those morphological changes are just evidence that this plant's environment has changed during its lifetime."

5) One way to improve crop productivity is to modify flowering time. This can allow for multiple growing seasons in one year, and can also increase grain production because a smaller plant has lower resource needs. You are approached by an agricultural company that wants to create an early-flowering transgenic plant. Using your knowledge of Arabidopsis genetics, which genetic modifications would you suggest?

A) Inhibition of the embryonic flower (EMF) gene or overexpression of the LEAFY (LFY) gene would work.

B) Inhibition of the LEAFY (LFY) gene or overexpression of the embryonic flower (emf) gene would work.

C) Inhibition of either the embryonic flower (emf) gene or the LEAFY (LFY) gene would work.

D) Early flowering is not possible in Arabidopsis, and is not likely to be possible in other plants.

6) Arabidopsis plants with a mutation in the gene embryonic Flower (EMF) produce flowers almost immediately after germination, before shoot growth occurs. What is the normal role of this gene?

A) The wildtype EMF allele causes growth of flowers in the embryo.

B) The wildtype EMF allele causes death of the shoot tissue.

C) The wildtype EMF allele prevents flowering from happening too soon.

D) The wildtype EMF allele prevents phase change and facilitates flower determination.

7) Interrupting the night with a flash of light can trigger flowering in a long-day plant. Why doesn't introducing a short period of darkness during the day cause a short-day plant to flower?

A) Sunlight contains enough far-red light to inhibit phytochrome induction of flowering.

B) A brief dark period is not sufficient to trigger flowering.

C) Phytochrome is only active in the dark.

D) The circadian clock is less responsive during the day than at night.

E) The phytochrome response also requires cool nighttime temperatures.

8) Which of the following statements about flowering plants is TRUE?

A) A short-day plant requires nights longer than a certain critical period to trigger flowering.

B) A long-day plant requires nights shorter than a certain critical period to inhibit flowering.

C) A short-day plant requires daylight of short wavelengths.

D) A long-day plant requires long wavelengths during the night.

E) A long-day plant requires long days alternating with short days.

9) Why do many plants use the photoperiodic pathway to regulate the timing of flower formation?

A) Flower petals carry out high levels of photosynthesis and require high light conditions.

B) A minimum amount of light is always necessary for flowering.

C) This allows plants to link flowering to temperature, which corresponds to the season when conditions are optimal.

D) This allows plants to link flowering to day length, which corresponds to the season when conditions are optimal.

10) You buy a Schlumbergera plant, also known as a Christmas Cactus, to decorate the desk where you study late into the night. It is now December, and there are no signs of flower buds forming. What is the most plausible explanation for the lack of flowers?

A) Flowering in this plant is controlled by both day length and temperature. The warm room and extended exposure to light are preventing flower formation.

B) The room is too cold for a cactus plant, which requires hot, desert conditions to flower.

C) Cacti are gymnosperms, not angiosperms, and thus do not form flowers.

D) As a long-day plant, the cactus requires a high light to dark ratio to flower, so it must be exposed to more sunlight.

11) The owner of a plant nursery is introducing the new night janitor to his duties. "Behind this door are the poinsettias," she said, "Please don't clean this room, and leave the door closed." Why might the owner say this?

A) Poinsettias are short-day plants that require a long uninterrupted period of darkness to flower. Even a short flash of light at night could prevent flowering.

B) Poinsettias are very sensitive to the chemicals used in cleaning, which can interfere with the gibberellin-dependent pathway and disrupt flowering.

C) Poinsettias are tropical plants and require constant warm temperatures for flower formation.

D) Poinsettias are long-day plants that require a long period of light for flower formation, and this light might disrupt the day-night cycles of other plants outside the room.

12) At a certain point in the flowering process, shoots become committed to making a flower. This is called

A) apomixis.

B) bilateralism.

C) phase change.

D) competence.

E) floral determination.

13) Competence means that a plant is  ________, while determination means that a plant tissue ________. The acquisition of flowering competence is an example of a ________.

A) capable of responding to signals that trigger a fate change; remains capable of adopting more than one possible developmental fate; phaseolus

B) unresponsive to signals that trigger a fate change; is committed to a specific developmental fate; fate change

C) in the process of responding to signals that trigger a fate change; was driven to adopt an abnormal developmental fate by transgene expression; flowerization

D) capable of responding to signals that trigger a fate change; is committed to a specific developmental fate; phase change

14) In the ABC model of floral determination, a different combination of the three genes specifies each floral organ. Which gene works in combination with the other two?

A) A

B) B

C) C

D) florigen

E) ethylene

15) At the Beautiful Mutants Flower Shop, a variety of unique mutant plants are sold. What would be the best flower to give to a friend who is allergic to pollen?

A) "Superhunk" -- a plant with a mutation in the class A genes.

B) "Beautiful Innocence" -- a plant with a mutation in the class C genes.

C) "Clockface" -- a plant with a mutation in the CYCLOIDEA gene.

D) "Suspense" -- a plant with a mutation in the LEAFY gene.

16) Flowering can be regulated by light, temperature, gibberellin levels, or internal factors. What do all of these different flowering pathways have in common?

A) All four pathways result in a decrease in LEAFY (LFY) expression, which induces flowering.

B) All four pathways result in an increase in CONSTANS (CO) expression, which induces flowering.

C) All four pathways result in an increase in LEAFY (LFY) expression, which induces flowering.

D) All four pathways result in a decrease in CONSTANS (CO) expression, which induces flowering.

17) A seed that lands in the forest soil is homozygous mutant for the LEAFY (LFY) gene, and as a result does not produce any functional LEAFY protein. What do you predict will happen during the development of this seed?

A) It will germinate and grow vegetatively, but will never produce flowers.

B) It will fail to germinate.

C) It will germinate and immediately produce flowers.

D) It will germinate and grow vegetatively. It will only develop flowers if it is from a species regulated by the autonomous flowering pathway.

18) A seed that lands in the forest soil is homozygous mutant for the CONSTANS (CO) gene, and as a result does not produce any functional CONSTANS protein. What do you predict will happen during the development of this seed?

A) It will germinate and grow vegetatively, but will never produce flowers.

B) It will fail to germinate.

C) It will germinate and grow vegetatively, and then it will produce flowers earlier than wildtype.

D) It will germinate and grow vegetatively. If it is from a photoperiodic species, it will fail to produce flowers.

19) How could you monitor flower determination in a plant that is mutant for all three class E SEP genes?

A) You cannot, because the class E mutant cannot make proper flowers.

B) Look for formation of sepals and petals.

C) Measure levels of SEP protein.

D) Measure levels of LEAFY and AP1 proteins.

20) Evolutionarily, floral parts represent modified

A) stems.

B) leaves.

C) roots.

D) stolons.

E) buds.

21) Ovules develop within the ovary, which is located in the swollen lower portion of which floral organ?

A) anther

B) stamen

C) filament

D) stigma

E) pistil

22) Which of the following is not a floral structure?

A) endosperm

B) calyx

C) corolla

D) stigma

E) style

23) Your botany instructor likes to tell nerdy jokes, like this: "I wanted to buy a pink Toyota Corolla, but the dealer only had a green Calyx available." Impress your instructor with a clever response to this joke.

A) "Oh, I would have chosen the blue Receptacle."

B) "Those are great cars, but the pinecone tires don't roll very well."

C) "Me too! But I could only afford the yellow Androecium."

D) "The factory must have run out of class A genes."

24) A researcher is investigating the morphology of complete flowers. Which of the following organs must his flowers contain?

A) calyx, corolla, receptacle, and carpels

B) calyx, corolla, carpels, and ovules

C) calyx, corolla, stamens, and anthers

D) calyx, corolla, carpels, and pistils

E) calyx, corolla, androecium, and gynoecium

25) A genus of primarily wind-pollinated plants includes one unusual species that has evolved to be pollinated by insects. Several morphological changes have accompanied this adaptation. The ________ are more colorful, there is a nectary at the base of the ________, the ________ are shorter and produce sticky pollen, and the ________ are stickier for enhanced pollen capture.

A) petals; stamens; sepals; carpels

B) petals; sepals; stamens; carpels

C) stamens; carpels; petals; sepals

D) petals; sepals; carpels; stamens

26) Some species of orchids attract pollinating Hymenoptera (bees and wasps) with flowers that closely mimic the appearance of a female insect. As the male attempts to mate with the flower, he becomes loaded with pollen, helping the plant to reproduce. If one of these orchid plants acquired a loss-of-function mutation in a CYCLOIDEA-like gene, what do you predict might happen?

A) The mutation would quickly spread through the population.

B) The mutant plants would have fewer available resources to devote to nectar production.

C) The mutant plants would attract larger numbers of pollinating male insects.

D) The mutation would fail to spread in the population.

27) Microspore mother cells produce microspores. What do microspores then develop into?

A) egg cells

B) pollen grains

C) synergids

D) endosperm

E) megaspores

28) Which of the following statements about the angiosperm embryo sac is FALSE?

A) It contains eight nuclei.

B) It is the gametophyte generation of the plant.

C) The nuclei within the embryo sac are diploid.

D) The synergids flank the egg cell.

E) The embryo sac nuclei are the product of mitotic division of a megaspore.

29) Which structure contains the angiosperm egg?

A) style

B) endosperm

C) anther

D) embryo sac

E) stigma

30) You are a landscape architect working on the grounds of a large estate. After you plant a dozen trees, the owner says, "There's been a mistake. The flowers on some of these willow trees look totally different! I specifically asked for Salix alba. You must have planted two different species." You refer to your tree guide, and read: "Salix alba - species of willow native to Europe and Asia, noted for the white undersides of leaves. Insect pollinated, dioecious. Grows 10-30m tall." How do you respond to the client?

A) "Sorry about that sir, I will dig up the wrong trees right away."

B) "Don't worry, the trees with the smaller flowers just haven't undergone phase change yet."

C) "Don't worry, when the shorter trees reach full size, they will grow the other kind of flower."

D) "Don't worry, Salix alba is dioecious, meaning each tree has either male or female flowers. That is why they look different."

31) Thanks to a novel recessive mutation, a certain plant species has begun to invade colder Arctic regions outside of its normal range. However, this cold-tolerant mutation has not yet become fixed in the population. A second mutation arises that promotes self-pollination. Do you predict that the self-pollination allele will be selected for in the Arctic regions? Why or why not?

A) Yes. The self-pollinated plant is more likely to maintain the cold-tolerant mutation, and plants in the Arctic are unlikely to be visited by pollinators.

B) No. Outcrossing is always beneficial, since it enhances genetic diversity.

C) No. Plants that produce flowers must be cross-pollinated for proper seed development.

D) Cannot make a prediction from the information given. It depends on whether the plant is normally insect-pollinated or wind-pollinated.

32) Which of these characteristics would most likely discourage self-pollination in a flower with both stamens and pistils?

A) many more stamens than pistils

B) long pistils and short stamens

C) long stamens and short pistils

D) wind pollination

E) determinant plants

33) Oaks, birches and corn produce both staminate and pistillate flowers on the same plant. What term describes this type of plant?

A) monoecious

B) dioecious

C) hermaphroditic

D) complete

E) determinant

34) Flowering plants use animals or wind to transfer ________ between flowers.

A) microspores

B) megaspores

C) ovules

D) seeds

E) pollen

35) In a wind-pollinated species, which of these floral parts is likely to be inconspicuous or absent?

A) receptacle

B) stamens

C) pistils

D) petals

E) stigmas

36) Early seed plants were pollinated by ________, as are present-day conifers.

A) beetles

B) bees

C) trilobites

D) wind

E) water

37) Which of these characteristics does not promote outcrossing in flowering plants?

A) self-incompatibility

B) dioecism

C) monoecism

D) physical separation of flower parts

E) apomixis

38) Which of the following factors is LEAST likely to attract pollinators to a flower?

A) the amount of nectar

B) odor

C) color of the flower in visible light

D) color of the flower in UV light

E) taste of the ovules

39) Which of the following statements about plant reproduction is incorrect?

A) Monoecious plants can have male and female flowers on the same plant.

B) Dioecious plants have male and female flowers on different plants.

C) Self-pollinating angiosperms are usually adapted to stable habitats.

D) Outcrossing promotes genetic diversity.

E) Self-pollinated plants must be visited by pollinators for fertilization to occur.

40) Some flowers have distinctive patterns that only reflect ultraviolet light and therefore are invisible to humans. Which statement about such markings is not correct?

A) The ultraviolet patterns are highly visible and attractive to bees.

B) Carotenoid pigments are responsible for the ultraviolet patterns.

C) The ultraviolet patterns often form a conspicuous central bull's eye or identify the best landing sites.

D) The ultraviolet patterns repel birds and bats from the flowers.

E) Flowers with ultraviolet patterns usually appear yellow or orange to humans.

41) Which of these is not an example of coevolution between flowers and pollinating bees?

A) Bees have tongues to lap up nectar.

B) Some bees are hairy to collect and carry pollen.

C) Flowers have ultraviolet markings visible to bees but invisible to most other insects.

D) Some flowers are bright red with long tubes to hold nectar.

E) Bees have strong preferences for particular types of flowers and remember where the plants are located.

42) Many plants devote significant resources to growing colorful, fragrant flowers filled with nectar. What does this illustrate the importance of?

A) nutrient storage in seeds

B) long-term nutrient storage in perennial plants

C) outcrossing

D) chemical signaling among plants

43) You and your neighbor each have a holly bush in your yards. You carefully water and care for your bush, but it fails to produce berries. Your neighbor, on the other hand, neglects his holly, yet it produces gorgeous red berries each year. Finally, in frustration, you replace your holly with a rose bush. The next year, your neighbor's holly bush has no berries at all. What happened?

A) Roses compete for the same insect pollinators as holly bushes.

B) Holly plants are dioecious. Yours was a male that was needed to pollinate the neighbor's female.

C) Roses secrete a chemical that inhibits the reproduction of neighboring plants.

D) The neighbor's bush became infected with the same disease that yours had.

44) What process results in the formation of the endosperm and the embryo in angiosperms?

A) alternation of generations

B) hydrolysis

C) determinate growth

D) double fertilization

E) secondary growth

45) Pollination begins when pollen is transferred from the ________ to the ________ of a flower.

A) anther; ovary

B) anther; receptacle

C) anther; stigma

D) stigma; embryo sac

E) synergid; egg

46) Which step is not involved in the fertilization of angiosperm flowers?

A) Pollen is transported to a stigma of a flower.

B) When pollen reaches the stigma of a flower, it begins to grow a pollen tube that pierces the style.

C) The style of the pistil contracts to bring the sperm closer to the embryo sac.

D) The pollen tube grows until it reaches the ovule in the ovary.

E) Double fertilization produces an embryo and the endosperm.

47) What is the best description of double fertilization in angiosperms?

A) One sperm fertilizes the egg, which develops into the embryo; the other sperm fertilizes the ovary, which becomes the fruit.

B) One sperm fertilizes the egg, which develops into the embryo; the other sperm fertilizes the polar nuclei, which forms the endosperm.

C) One sperm fertilizes the egg, which develops into the embryo; the other sperm fertilizes the polar nuclei, which forms the seed coat.

D) One sperm fertilizes the egg, which develops into the embryo; the other sperm produces the pollen tube.

E) One pollen grain fertilizes the embryo sac; the other sperm fertilizes the pollen grain.

48) "Germination" can refer to two different events

A) the arrival of the pollen grain at the ovule, and the growth of the seedling from the seed.

B) the development of the flower, and the growth of the seedling from the seed.

C) the growth of the pollen tube into the embryo sac, and the growth of the seedling from the seed.

D) the development of the fruit from the ovary, and the growth of the seedling from the seed.

49) You go to the movies with a friend, and he refuses to share your popcorn. He says that he heard that movie theatre popcorn is triploid. What is the most likely explanation for this?

A) Most corn is genetically modified by large agricultural companies.

B) The buttery topping on movie theatre popcorn causes chromosomal abnormalities.

C) Popcorn is made from a different species of maize than regular corn.

D) All popcorn is triploid, because the starchy part of the kernel is triploid endosperm tissue.

50) If a pollen grain fails to generate two sperm cells, what is the most likely result of pollination?

A) Half the seeds would develop fine, but the other half would die.

B) The resulting progeny would be haploid.

C) The seeds would lack either embryos or endosperm, and so would be nonviable.

D) The endosperm would be smaller.

51) What are the "seed leaves" that grow from bulges on the embryo called?

A) radicles

B) embryo sacs

C) petioles

D) cotyledons

E) ovules

52) The HOBBIT gene in an embryo helps to control the development of what structure?

A) cotyledon

B) endosperm

C) root

D) epicotyl

E) root hair

53) Which of the following statements about plant development is true?

A) The radial axis of the developing embryo develops before the root-shoot axis.

B) A single gene is responsible for the control of all root and shoot formation.

C) The MONOPTEROS gene (MP) stimulates chlorophyll synthesis in seeds.

D) Gibberellic acid is important in root-shoot axis formation.

E) Cells nearest to the suspensor ultimately form the root.

54) What do the two daughter cells generated by the first asymmetric division of the plant zygote become?

A) the suspensor and the embryo

B) the epicotyl and the hypocotyl

C) the root and the shoot

D) the egg and pollen

E) the xylem and the phloem

55) Which of the following statements about plant embryo development is correct?

A) The suspensor forms from the shoot apical meristem before development of the root apical meristem.

B) The development of the shoot and root apical meristems is controlled independently.

C) The plant hormone abscisic acid is important in the development of the shoot-root axis.

D) The protoderm establishes the procambium tissue in the young plant embryo.

56) What does the globular stage of plant embryo development give rise to?

A) a heart-shaped dicot embryo

B) the suspensor of the germinating seed

C) a double monocot embryo

D) the monocot scutellum

E) the rhizoid of Fucus

57) What did experiments with the brown alga Fucus help to determine?

A) The cytoplasm is evenly distributed throughout the algal zygote.

B) The thallus anchors the alga to the surface on which it lives.

C) Light and gravity do not affect rhizoid orientation.

D) Magnesium gradients are important for cell wall formation.

E) A cell wall is required for the zygote to "remember" where a rhizoid should form.

58) Which structure can still develop normally in an embryo with mutations in both the SHOOTMERISTEMLESS (stm) gene and the HOBBIT gene?

A) root cap

B) shoot apical meristem

C) root apical meristem

D) leaf primordia

E) cotyledons

59) What is the name of the meristematic tissue that gives rise to future vascular tissue?

A) procambium

B) cork cambium

C) ground meristem

D) dermal tissue

E) protoderm

60) What is the name of the elongated structure that links the embryo to the nutrient tissue of the seed?

A) suspensor

B) cotyledon

C) epicotyl

D) style

E) ovule

61) Which of these structures does not begin development during embryogenesis?

A) apical meristem

B) vascular tissue

C) floral primordia

D) leaf primordial

E) ground tissue

62) Which of these is not part of a seed?

A) endosperm

B) embryo

C) diploid cells

D) seed coat

E) fruit

63) Endosperm tissue of angiosperms has what ploidy level?

A) n

B) 2n

C) 3n

D) 4n

E) 8n

64) Germination requires the use of metabolic reserves in the seed. Which of these compartments contains starch used to fuel early seedling growth?

A) amyloplasts

B) protoplasts

C) chloroplasts

D) chromoplasts

E) mitochondria

65) Which of the following is not a feature of a seed?

A) It contains a protective coat formed from the outer layers of ovule cells.

B) The embryo is surrounded by nutritive tissue or has cotyledons that contain nutritive tissue.

C) It contains a large percentage of water to support the embryo.

D) It is a complex structure that allows the embryo to be dispersed to distant sites.

E) Environmental signals such as light or temperature can trigger germination.

66) Why do oils form a significant part of the nutritional reserves in many seeds?

A) Oils help keep the embryo hydrated, allowing the seed to survive in dry habitats.

B) The oils reduce the density of the seed and allow for water dispersal.

C) Oils contain more mineral nutrients than carbohydrates.

D) Oils store twice as much energy as an equivalent mass of starch.

E) Hormones diffuse more quickly through oils.

67) What is the term for the single cotyledon within the kernels of cereal grains?

A) aleurone

B) hypocotyl

C) dicot

D) scutellum

E) amyloplast

68) What is the portion of a dicot seedling below the cotyledons called?

A) internode

B) epicotyl

C) hypocotyl

D) plumule

E) subcotyl

69) Stratification refers to the extended exposure to ________ that is required for some seeds to germinate.

A) long wavelengths of light

B) low temperatures

C) high relative humidity

D) short daylengths

E) clay soil particles

70) Which structure does not represent a mode of vegetative reproduction?

A) runners

B) rhizoids

C) adventitious plantlets

D) suckers

E) rhizomes

F) stolons

71) What are plants that flower only once before they die, normally after two seasons of growth, called?

A) annuals

B) biennials

C) perennials

D) monocots

E) dicots

72) Which part of the seed produces hydrolytic enzymes that break down the starchy endosperm during seed germination?

A) scutellum

B) amyloplasts

C) aleurone layer

D) plumule

E) coleorhiza

73) When a seed germinates, the embryo emerges from its dormancy and begins which phase of the plant life cycle?

A) sporophyte generation

B) gametophyte generation

C) dicot generation

D) monocot generation

E) alternate generation

74) Which of the following statements about the epicotyl is true?

A) It remains in the ground after a seed has germinated.

B) It is the portion of the stem axis that is directly below the cotyledons.

C) The shoot apical meristem of a seedling is located just above it.

D) It takes up most of the volume within a monocot or dicot seed.

E) It forms immediately above the secondary roots of a seedling.

75) Despite its name, Kentucky Bluegrass is a widespread turfgrass used for lawns throughout the United States. In some regions, strains have developed desirable disease-resistant properties. However, Kentucky Bluegrass typically develops by apomixis. Plant breeders say this creates both a challenge and an opportunity for engineering novel strains. Why?

A) In apomixis, new plants develop from underground horizontal stems. This allows for fast propagation of new strains, but all progeny are identical to the parent. 

B) Plants that develop by apomixis are naturally tolerant of herbicides. As a result, herbicide tolerance genes cannot be used as selectable markers for a transgene, but herbicides can be used to keep the resulting culture pure.

C) Since the progeny of apomixis are triploid, hybrids have an imbalance of parental genes. However, this may be desirable if a higher proportion of one allele is beneficial.

D) If a seed develops by apomixis, it will be identical to its parent. Hybridization with another strain requires special techniques. However, once a hybrid strain is developed, apomixis ensures its reliable propagation.

76) Dandelions develop seeds by apomixis. What benefits does this strategy provide over vegetative or sexual reproduction?

A) Apomixis makes the dandelions more resistant to herbicides.

B) Apomixis provides the benefits of seed dispersal, while maintaining a genome adapted to a given climate.

C) Apomixis is beneficial in sheltered areas where wind pollination would be difficult.

D) Apomixis is beneficial for plants that attract a diverse mix of bees and other pollinators.

77) Which tissue can not divide to give rise to identical progeny in a plant that reproduces asexually?

A) root

B) stem

C) leaf

D) pollen grain

E) ovule

78) Which of the following statements about plant tissue culture is false?

A) Virus-free crop species can be propagated by culturing meristems.

B) Individual cells can give rise to whole plants through tissue cultures.

C) Synthetic hormones can be used to selectively promote root or shoot formation.

D) Callus tissue can only form roots, not shoots.

E) A callus is a mass of undifferentiated cells.

79) Place these statements in their proper sequence.

Walking through the botanical garden with a friend, you spy a rare and beautiful variety of Hosta. "Oh I would love to have one of those!" you exclaim. "But they cost a king's ransom." Your friend smiles, snips off a tiny piece of the shoot, and says, "I'll grow you one. I'll just take it back to lab and...

1. use enzymes to break down the cell walls..."

2. grow up a callus..."

3. wait for somatic embryos to form..."

4. culture an individual plantlet for you..."

80) Rank these plant types from those that undergo senescence soonest after seed germination to those that live longest.

1. herbaceous perennial

2. biennial

3. annual

4. woody perennial

81) Browsing through a seed catalog, you are tempted to order several beautiful floral varieties, but worry that you will spend too much on your garden every year. Which plants should you buy?

A) herbaceous perennials, which will come back year after year

B) woody perennials, which require little space and few resources

C) annuals, which will come back year after year

D) biennials, which will last twenty years before they die

82) Heirloom plants are treasured for their flavorful produce and true-breeding progeny that allow gardeners to avoid repeatedly purchasing seed from agribusiness conglomerates. What special effort is required to save seed from heirloom biennials such as carrots?

A) Since carrots produce large roots, they do not devote many resources to seed development. The roots must be trimmed before collecting seed.

B) Since carrots build up so much beta-carotene, they do not devote many resources to seed development. A yellow carrot variety will produce better seeds than a darker one.

C) Since carrots are related to wild weeds, they are often cross-pollinated. The green top must be bagged to ensure self-pollination.

D) Biennials do not produce seed until the second year of growth. Although carrot roots are normally harvested after one season, they must be allowed to grow another year for seed collection.

83) Which of the following events is not a characteristic of successful seed germination?

A) The radicle breaks through the seed coat.

B) The shoot becomes photosynthetic.

C) The embryo becomes desiccated.

D) New growth occurs at the meristems.

E) The seedling orients itself relative to gravity.

84) Your friend has never gardened before. When none of the seeds he planted germinate, he asks you to suggest why. Which is the best explanation of what occurred?

A) The monocot seeds he used were only able to produce a single cotyledon each.

B) The seeds were planted too deeply and used up their reserves before reaching the surface and sunlight.

C) The suspensor failed to develop into an embryo within each seed.

D) All seeds require fire in order to germinate.

E) Seeds take more than one season to germinate.

85) Why can scratching or chipping the seed coat speed up the germination of hard-coated seeds like alfalfa?

A) The mechanical stress activates hydrolytic enzymes.

B) Water and oxygen can enter the seed to reach the embryo more quickly.

C) Carbon dioxide can enter the seed and stimulate photosynthesis.

D) Bacteria or fungi can enter the seed and release growth factors.

E) Damage to the seed coat triggers the aleurone layer to release amylase.

86) Scientists have confirmed by carbon dating that seeds dormant for up to 2000 years can successfully germinate. Based on the requirements for germination, what research expedition should you join in order to retrieve some ancient but viable seeds?

A) A trip to Indonesia, where the civet cat eats and expels coffee beans, producing a gourmet coffee known as Kopi Luwak.

B) A trip to the Irish marsh, where wet peat creates anaerobic conditions, and your colleagues hope to unearth a bog mummy.

C) A trip to the Burgess Shale in Canada, where your paleontologist colleagues have found fossils from the Cambrian era.

D) A trip to the arid Dead Sea region, where your historian colleagues have found a storeroom of wax-sealed jars.

Choose the letter of the best match from the following:

A. hypocotyl

B. endosperm

C. scutellum

D. radicle

E. epicotyl

87) The stem axis of the embryo below the cotyledons in some seedlings.

88) A single cotyledon found in the kernels of cereal grains.

89) Nutritive tissue within angiosperm seeds.

90) The part of the stem axis that extends above the cotyledons in some seedlings.

91) Pea plants are self-pollinators. What can you further deduce about peas? (Check all that apply.)

A) Peas will be more resistant to garden pests than other plants.

B) Peas are less likely to invade highly variable natural environments than other plants.

C) A gardener planning to collect heirloom seeds can plant different varieties of peas near each other.

D) Peas will be more resistant to new plant diseases.

E) To perform his pea cross-pollination experiments, Gregor Mendel must have first removed the stamens from flowers to prevent self-pollination.