Ch22 Test Bank Docx Early Development of the Plant Body

Chapter 22: Early Development of the Plant Body

Multiple-Choice Questions

A plant’s body plan consists of a(n) ______ and a(n) ______ pattern.

a. apical-radial; basal

b. apical-basal; radial

c. basal-radial; apical

d. apical; basal

e. radial; apical

When the zygote first divides, the two daughter cells are the ______ cell and the ______ cell.

a. micropylar; chalazal

b. root; shoot

c. apical; basal

d. proembryo; suspensor

e. axis; proembryo

Located at the micropylar pole of the embryo is the:

a. apical cell.

b. embryo proper.

c. proembryo.

d. protoderm.

e. basal cell.

Which of the following statements about the polarity of an embryo is FALSE?

a. It fixes the structural axis of the body.

b. It is established only after the zygote has divided.

c. It is essential to the development of all higher organisms.

d. It refers to the condition in which one end is different from the other end.

e. It is a key component of biological pattern formation.

Which primary meristem forms first?

a. shoot apical meristem

b. root apical meristem

c. ground meristem

d. protoderm

e. procambium

Which of the following statements concerning primary meristems is FALSE?

a. An example is the suspensor.

b. An example is the procambium.

c. An example is the ground meristem.

d. They are formed during embryogenesis.

e. They are meristematic.

The procambium is the precursor of the:

a. epidermis.

b. ground tissues.

c. protoderm.

d. xylem and phloem.

e. primary meristems.

During early embryogenesis, the ground meristem surrounds the:

a. epidermis.

b. procambium.

c. protoderm.

d. epidermis.

e. ground tissues.

Which of following lists the correct developmental sequence in eudicots, where I is the globular stage; II, the heart stage; III, the proembryo; IV, the torpedo stage; and V, the zygote?

a. V, III, I, II, IV

b. I, V, IV, II, III

c. III, V, II, IV, I

d. V, I, III, II, IV

e. V, III, II, I, IV

In embryogenesis in monocots, globular embryos next become:

a. two-lobed.

b. curved.

c. cylindrical.

d. heart-shaped.

e. spherical.

The root and shoot apical meristems first become discernible during the transition between the ______ and ______.

a. proembryo; globular stage

b. torpedo stage; proembryo

c. heart stage; globular stage

d. globular stage; torpedo stage

e. torpedo stage; embryo proper

The cotyledons elongate most dramatically and may become curved during the _______ stage.

a. proembryo

b. torpedo

c. suspensor

d. heart

e. globular

Where does the shoot apical meristem arise in eudicot embryos?

a. at the tip of a sheathlike extension

b. at the tip of a cotyledon

c. on one side of the single cotyledon

d. on one side of the two cotyledons

e. between the two cotyledons

Normal development of the ______ prevents formation of extra embryos by the ______.

a. embryo proper; apical meristems

b. primary meristems; embryo proper

c. suspensor; apical meristems

d. embryo proper; suspensor

e. suspensor; embryo proper

During embryogenesis in Arabidopsis, mutants with the twn mutation:

a. form no viable embryos.

b. produce no food reserves.

c. form secondary embryos from the suspensor.

d. produce a suspensor that dies prematurely.

e. produce a suspensor that loses its polarity.

In Arabidopsis, embryonic development is thought to be coordinated by at least ______ distinct genes.

a. 50

b. 150

c. 350

d. 550

e. 750

The stem-like axis above the cotyledon(s) is the:

a. epicotyl.

b. hypocotyl.

c. plumule.

d. funiculus.

e. radicle.

Which of the following CANNOT be part of the plumule?

a. shoot apical meristem

b. young leaves

c. radicle

d. epicotyl

e. stem-like axis

In some embryos, below the hypocotyl the _________ is found.

a. epicotyl

b. radicle

c. plumule

d. coletoptile

e. shoot apical meristem

In eudicots, in which most of the endosperm is absorbed by the embryo, the cotyledons:

a. are large and fleshy.

b. are thin and membranous.

c. develop into the scutellum.

d. are absent.

e. absorb stored food during resumption of embryonic growth.

The cotyledon of grasses is called a(n):

a. scutellum.

b. hypocotyl.

c. epicotyl.

d. coleorhiza.

e. hilum.

In monocots, the cotyledon can have all of the following functions EXCEPT:

a. protection of the plumule.

b. photosynthesis.

c. absorption of nutrients.

d. storage of nutrients.

e. transport of nutrients.

In a grass embryo, the coleorhiza encloses the:

a. scutellum.

b. hypocotyl.

c. radicle.

d. epicotyl.

e. plumule.

The integuments develop into the:

a. hilum.

b. seed coat.

c. funiculus.

d. coleoptile.

e. endosperm

Which of the following statements about the seed coat is FALSE?

a. It develops from the ovary.

b. It protects the embryo.

c. It may be papery or very hard.

d. It may be impermeable to water.

e. The micropyle may be visible on the seed coat.

In grasses, the pericarp consists of the:

a. mature ovary wall only.

b. remnants of the seed coat only.

c. remnants of the scutellum only.

d. mature ovary and remnants of the seed coat only.

e. mature ovary, remnants of the seed coat, and remnants of the scutellum.

The scar left on the seed coat after the seed has separated from its stalk is called the:

a. micropyle.

b. funiculus.

c. hilum.

d. suspensor.

e. integument.

Which of the following statements concerning the maturation phase of seed development is FALSE?

a. The seed undergoes desiccation.

b. Food reserves accumulate in the endosperm and/or cotyledons.

c. The seed coat hardens.

d. Starch, proteins, and oils accumulate.

e. Cell division in the embryo accelerates.

Which of the following events is NOT associated with seed germination?

a. imbibition

b. activation of existing enzymes

c. synthesis of new enzymes

d. synthesis of food reserves

e. initiation of cell division and cell enlargement

When the seed coat is ruptured during germination, the seed:

a. switches to anaerobic glucose breakdown.

b. switches to aerobic respiration.

c. first begins to use glucose as a fuel molecule.

d. no longer uses glucose as a fuel molecule.

e. is no longer able to use oxygen.

A quiescent seed is different from a dormant seed in that a quiescent seed will germinate:

a. when hydrated.

b. under anaerobic conditions.

c. in the presence of growth inhibitors.

d. when the embryo is physiologically immature.

e. under suboptimal temperature conditions.

Which of the following would not typically cause coat-imposed dormancy?

a. impermeability of the seed coat to water

b. impermeability of the seed coat to oxygen

c. prevention of the release of growth promoters from the seed

d. rigidity of the seed coat

e. prevention of the release of growth inhibitors from the seed

Embryo dormancy would typically be caused by:

a. unfavorable external conditions.

b. the seed coat preventing the release of abscisic acid.

c. an increase in gibberellic concentrations.

d. a decrease in abscisic acid concentrations.

e. an increase in abscisic acid concentrations.

The process of after-ripening involves:

a. enzymatic modification of a dormant seed so that it will germinate.

b. biochemical conversion of a germinating seed to a dormant seed.

c. cessation of the flow of nutrients from the parent plant to the ovule.

d. stimulation of the primary meristems to develop.

e. desiccation and hardening of the seed coat.

In temperate regions of the world, after-ripening is triggered by:

a. drought.

b. high humidity.

c. low temperature.

d. high temperature.

e. low oxygen levels.

What induces the seeds of manzanita and other plants of the California chaparral to germinate?

a. light

b. fire

c. rainfall

d. activity of digestive enzymes

e. low temperature

The ______ is usually the first structure to emerge from a germinating seed.

a. epicotyl

b. hypocotyl

c. cotyledon

d. root

e. coleoptile

In monocots, the root system commonly develops from:

a. branch roots.

b. stem-borne roots.

c. the primary root.

d. the secondary root.

e. the taproot.

In epigeous germination, which structure emerges above ground first?

a. cotyledon

b. epicotyl

c. hypocotyl

d. coleoptile

e. radicle

In the pea (Pisum sativum), the ______ forms the hook that pushes to the soil surface during seed germination.

a. coleoptile

b. cotyledon

c. hypocotyl

d. epicotyl

e. radicle

Which of the following statements about seed germination in onion (Allium cepa) is FALSE?

a. Germination is hypogeous.

b. The plumule emerges from the cotyledon.

c. The cotyledon becomes photosynthetic.

d. The cotyledon forms the hook.

e. The stored food is found in the endosperm.

In maize (Zea mays), the first structure to emerge from the seed during germination is the:

a. epicotyl.

b. hypocotyl.

c. radicle.

d. coleorhiza.

e. coleoptile.

True-False Questions

The radial pattern of embryogenesis consists of concentrically arranged tissue systems.

In most angiosperms, the first division of the zygote is symmetrical and longitudinal to the long axis of the zygote.

In angiosperms, polarity can be established either with the first division of the zygote or before.

The suspensor anchors the embryo at the micropyle.

The suspensor is part of the embryo proper.

The root and shoot apical meristems are two of the primary meristems.

The protoderm is formed by anticlinal divisions of the outermost cells of the embryo proper.

In the heart stage of development, the lobes of the “heart” are the cotyledons.

The apical meristems are the source of virtually all of the tissues of the seedling and adult plant.

The suspensor is an example of a structure that undergoes programmed cell death.

The embryonic root is called the radicle.

Seeds with large cotyledons typically have little or no endosperm.

The cotyledon of grasses is called a scutellum.

The coleoptile and coleorhiza are typically found in monocots and eudicots.

In a grass embryo, the coleoptile encloses the plumule.

In grasses, the pericarp is found immediately inside the seed coat.

The funiculus is the stalk of the seed.

Metabolism increases toward the end of the maturation phase of seed development.

Before a seed can germinate, it must first imbibe water.

Before the seed coat ruptures during germination, glucose breakdown may be entirely anaerobic.

A quiescent seed will not germinate even when external conditions are favorable.

An example of coat-imposed dormancy is a mechanically rigid seed coat.

The dormancy acquired during seed maturation is called primary dormancy.

In temperate regions, after-ripening ensures that seeds will germinate in the fall rather than in the spring.

In hypogeous germination, the cotyledons remain in the soil.

In maize, the pericarp functions as the seed coat.

Essay Questions

1. Formation of the Embryo; pp. 526–527, 529; moderate

Discuss the concept of polarity as it pertains to angiosperm embryogenesis.

2. Formation of the Embryo; p. 529; moderate

Define the term “primary meristem.” Name the three primary meristems, and name the tissue(s) into which each develops.

3. Formation of the Embryo; p. 529; moderate

List the principal stages of embryonic development in angiosperms, and describe the appearance of the embryo at each stage.

4. Formation of the Embryo; p. 530; difficult

The Arabidopsis gnom mutant (shown in Figure 22-5) consists of only a stem-like structure containing an epidermis, ground tissue, and vascular tissue. What typical embryonic parts is this seedling missing? What might be the function of the gnom gene in seedling development?

5. Formation of the Embryo; pp. 529–530; moderate

Give three examples of types of genes that govern Arabidopsis embryogenesis. What happens when these genes are mutated?

6. The Mature Embryo; pp. 530–531; difficult

A mutant garden bean seed is found that lacks endosperm. What would you expect this seed to look like? Name two other tissues that can have the same role as endosperm.

7. The Mature Embryo; p. 531; moderate

Explain the relationship between the epicotyl, the apical meristem, and the plumule.

8. The Mature Embryo; p. 531; moderate

Describe the various roles played by cotyledons in angiosperms.

9. Seed Maturation; p. 532; moderate

List the events that take place during the maturation phase of seed development. What is the difference between a dormant seed and a quiescent seed?

10. Requirements for Seed Germination; p. 533; moderate

Define seed dormancy. Are the packaged seeds that you buy at the store likely to be dormant? Why or why not?

11. Requirements for Seed Germination; pp. 533–534; moderate

What are the two most common causes of seed dormancy? Discuss some of the ways in which seeds can overcome dormancy.

12. From Embryo to Adult Plant; pp. 535–536; moderate

Onion (Allium cepa) and maize (Zea mays) are monocots, but they differ in certain features of germination. Outline these differences.