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20
PLANT ANATOMY
AND
GROWTH
CHAPTER REVIEW
In a plant, the root anchors it, absorbs water and minerals, and stores the products of photosynthesis. Two associations assist roots in gathering nutrients: mycorrhizae
is a mutualistic association of fungi with the small roots
of plants and root nodules contain bacteria that can fix
aerial nitrogen, making nitrogen compounds available
to a plant.
Stems support leaves and conduct materials to and
from roots and leaves. Both the root tip and shoot tip
(terminal bud) contain apical meristem. During primary
growth, apical meristem produces new cells that undergo
differentiation to produce three types of tissue: epidermal tissue (protects), ground tissue (fills spaces), and
vascular tissue (transports). Xylem transports water and
minerals; phloem transports sucrose and organic nutrients. The cohesion-tension model explains how water is
transported in xylem and the pressure-flow model ex-
plains transport in phloem.
The distinction of vascular bundles in a stem indicates whether the plant is a monocot or eudicot. During
secondary growth of a woody eudicot, vascular cambium,
a meristem tissue, produces secondary phloem and secondary xylem each growing season. A woody stem has
three regions: bark, wood, and pith. The bark and wood
are separated by vascular cambium. Bark includes cork,
cork cambium, and phloem. Rings of xylem from previous seasons build up to form wood.
In cross section, leaves, which carry on photosynthesis, have mesophyll tissue between upper and lower
layers of epidermis. Guard cells, in particular the upper
epidermis, regulate the opening and closing of stomata.
Evaporation of water by way of the stomata, called transpiration, creates a pull that causes water to flow up the
stem to the leaves.
CHAPTER KEY TERMS
After studying the key terms of this chapter, match the phrases below with the alphabetized list of terms.
eudicot
node
herbaceous
phloem
internode
transpiration
lateral bud
vascular bundle
meristem
wood
monocot
xylem
a. tissue in the active growth regions of plants _______________________
b. vascular tissue that conducts organic solutes _______________________
c. plant group, flower has multiples of four or five parts _______________________
d. vascular tissue that transports water and mineral solutes upward through the plant body _______________________
e. nonwoody stem _______________________
f. place where one or more leaves attach to a stem _______________________
g. primary phloem and primary xylem enclosed by a bundle sheath _______________________
h. plant’s loss of water to the atmosphere _______________________
i. plant group, flower has one part _______________________
j. secondary xylem that build up year after year _______________________
k. site on a stem where lateral branches grow _______________________
l. region of a stem between two successive nodes _______________________
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S T U DY E X E R C I S E S
Study the text section by section as you answer the questions that follow.
20.1 PLANT ORGANS (PP. 338–340)
• The organs of a plant are the leaves, the stem, and the root.
• Growth occurs from both the shoot tip and the root tip.
• The organization of organs differs in monocots and eudicots.
1. The root system
and
c. ____________________
leaves and
at a
a. ____________________
from the soil, especially by means of
e. ____________________
f. ____________________.
the plant in the soil and absorbs
b. ____________________
d. ____________________.
Stems support the
water and minerals from roots to the leaves. A leaf and a lateral bud occur
The leaves carry on
g. ____________________,
h. _________________________________________
which requires
(list the three requirements).
2. Place a check in front of the correct descriptions of leaves:
a.
spines of a cactus
b.
tendrils of a cucumber
c.
trap of a Venus’s flytrap
3. Label each type of root shown and describe its special function:
a.
b.
c.
4. Complete the following table to indicate the differences between monocot and eudicot plants:
Plant Part
Monocot
Eudicot
Leaf veins
Vascular bundles in stem
Cotyledons in seed
Vascular tissue in root
20.2 PLANT TISSUES
AND
CELLS (PP. 341–342)
• In plants, epidermal tissue is protective; ground tissue forms the bulk of the leaves, stems, and root; vascular
tissue transports water and nutrients.
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5. Match the cell types with these tissue types:
1. epidermal tissue
2. ground tissue
3. vascular tissue
a.
sclerenchyma cells
b.
tracheids
c.
root hair cells
d.
parenchyma cells
e.
sieve-tube members
f.
vessel elements
6. Indicate whether each of these statements is true (T) or false (F).
Epidermal Tissue:
a.
Epidermis covers the entire body of nonwoody plants.
b.
Epidermis covers the entire body of young woody plants.
c.
Epidermis replaces cork in the stems of older plants.
d.
Guard cells regulate the entrance of water into the roots.
Ground Tissue:
e.
Collenchyma cells are a major site of photosynthesis.
f.
Collenchyma cells have thinner primary walls than parenchyma.
g.
Parenchyma cells are the least specialized cell type.
h.
Sclerenchyma cell secondary walls are impregnated with lignin.
i.
Most sclerenchyma cells are nonliving.
Vascular Tissue:
j.
Phloem transports organic nutrients from leaves to roots.
k.
Sieve-tube members are found in xylem.
l.
Tracheids are a type of cell in phloem.
m.
Xylem transports water from roots to leaves.
20.3 ORGANIZATION
OF
LEAVES (PP. 342–343)
• Leaf veins terminate in the mesophyll of leaves, where photosynthesis takes place.
• The stomata of leaves carry on gas exchange and allow water vapor to escape into the environment.
7. Label the following diagram of a leaf using the alphabetized list of terms:
cuticle
leaf vein
lower epidermis
palisade mesophyll
spongy mesophyll
upper epidermis
a.
b.
c.
d.
e.
f.
Using these same terms, fill in the blanks.
An extension of stem vascular bundles into a leaf is called the
h. ____________________
g. ____________________.
protects the leaf from drying out. The
The
i. ____________________
Elongated cells that photosynthesize are the
j. ____________________.
photosynthesize and exchange gases are the
k. ____________________.
allow gas exchange.
Loosely arranged cells that
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20.4 ORGANIZATION
OF
STEMS (PP. 344–345)
• The primary growth of a shoot produces new leaves and adds to stem length.
• In woody stems, secondary growth consists of annual rings of xylem that increase the girth of stems.
8. To label these diagrams of herbaceous stems, place a letter next to the appropriate term.
_____ cortex
c.
_____ epidermis
a.
_____ phloem
a.
_____ pith
_____ vascular bundle
_____ xylem
b.
c.
d.
e. What two types of tissues occur in a vascular bundle? ____________________ and ____________________
9. a. How would you describe the arrangement of vascular bundles in a herbaceous monocot stem?
____________________
b. In a herbaceous eudicot stem? ____________________
10. Label the following diagram of a pie-shaped section of a woody twig as follows:
1. Label bark, vascular cambium, and wood.
2. Within the bark, label cork and
phloem.
3. Within wood, label annual ring.
g. What is the function of vascular cambium,
a meristem tissue? ____________________
________________________________________
d.
cortex
a.
e.
b.
h. The ____________________ tell the age of a
tree. How old is this tree? __________________
f.
c.
Pith
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20.5 ORGANIZATION
OF
ROOTS (PP. 346–347)
• Primary growth adds to root length, and the pericycle produces lateral roots.
11. To label this diagram of a eudicot root tip place a letter next to the appropriate term.
_____ cortex
_____ endodermis
_____ epidermis
_____ pericycle
_____ phloem
_____ root cap
_____ root hair
_____ vascular tissue
_____ xylem
_____ zone of cell division
_____ zone of elongation
_____ zone of maturation
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12. Explain what is happening in each of these zones of a root tip:
a. cell division _____________________________________________________________________________________________
b. elongation _______________________________________________________________________________________________
c. maturation _______________________________________________________________________________________________
13. Match the statements with a particular tissue or part of the root listed (not all answers are needed):
1. epidermis
2. endodermis
3. pericycle
4. cortex
5. phloem
6. xylem
7. vascular tissue
a.
Contains parenchyma cells, which function in food storage.
b.
Consists of an outer layer of cells that may bear a root hair for absorption of water.
c.
A layer of cells just inside the endodermis that can divide and produce a branch root.
d.
Contains phloem and xylem.
e.
Vascular tissue that transports water and minerals.
f.
Vascular tissue that transports sugars.
20.6 PLANT NUTRITION (P. 348)
• Plants require only inorganic nutrients to produce all the organic compounds of their bodies.
• Roots are adapted to take up some minerals through mutualistic relationships with bacteria and fungi.
14. Label each of the following as either a macronutrient (MA) or micronutrient (MI). Place the appropriate
letters next to each item:
MA—macronutrient
MI—micronutrient
a.
carbon
b.
hydrogen
c.
iron
d.
manganese
e.
potassium
f.
boron
15. Identify the following associations as either root nodules or mycorrhizal:
a. The bacteria supply the plant with nitrogen compounds and the plant supplies the bacteria with
carbohydrates. ____________________
b. Fungal hyphae supply inorganic nutrients to the plant and the plant supplies fungus with sugars and amino
acids. ____________________
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20.7 TRANSPORT
OF
NUTRIENTS (PP. 349–351)
• The cohesion-tension model accounts for transport of water and minerals in xylem.
• The pressure-flow model accounts for transport of organic nutrients in phloem.
16. Label the following diagram of the cohesion-tension model of xylem transport by providing the description of
events. Also label water where appropriate:
a.
b.
c.
d.
e.
17.
a. ______________________ are
the conducting cells in xylem. b. ______________________ absorb water from soil.
Why does water evaporate? Solar c. __________________________________________________________________.
d. ______________________ is
created by the evaporation of water. It pulls the e. ______________________ from
the roots to the leaves. f. ______________________ and ______________________ cause the water column to hold
together. Why must the water column be continuous? g. ______________________
18. Using the input from question 17, explain the cohesion-tension model of xylem transport. __________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
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19. Label the following diagram of a stomata and answer the following questions.
a.
b.
j.
c.
Open
Closed
d. The arrows represent the movement of water molecules. When water (exits, enters)
______________________ guard cells, stomata close.
20. When water enters guard cells, a. ______________________ pressure develops and this causes stomata to
b. ______________________. Now
transpiration can occur.
21. What two important events are occurring when stomata are open?
a. ________________________________________________________________________________________________
b. ________________________________________________________________________________________________
22. Use the boxes in the following diagram to
explain the pressure-flow model of phloem
transport:
23.
a. ______________________ are
the conducting
cells of phloem. Why can substances move
from cell to cell in phloem? b. ______________
Source:
Sugar is actively
transported into sieve
tubes, and water
follows by osmosis.
____________________________ Leaves are a
c. ______________________ because they make
sugar. d. ______________________ causes sugar
to enter phloem. e. ______________________
occurs after sugar enters phloem.
f. ______________________ exists
in phloem
after sugar and water enter.
g. ______________________ causes
sugar to exit
phloem. Why is the exit of sugar from phloem
a necessary part of phloem transport? h. ______
This creates a positive
pressure that causes
a flow within phloem.
Sink:
Sugar is actively
transported out of
sieve tubes, and water
follows by osmosis.
____________________________ Roots are the
i. ______________________ because
sugar is
removed in roots.
24. Using the input from question 23, explain the pressure-flow model of phloem transport.
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
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K E Y WO R D C RO S S WO R D
Review key terms by completing this crossword puzzle, using the following alphabetized list of terms:
1
2
3
4
5
6
7
8
10
11
12
13
9
cork cambium
cotyledon
cuticle
endodermis
epidermis
herbaceous
leaf
meristem
mesophyll
palisade mesophyll
parenchyma
phloem
root hair
spongy mesophyll
stem
vascular cambium
xylem
14
15
16
17
Across
1 in plants, the covering tissue of roots, leaves, and
also stems of nonwoody organisms
4 least specialized of all plant cell or tissue types;
contains plastids and is found in all organs of a
plant
5 usually broad, flat structure of a plant shoot system, containing cells that carry out photosynthesis
6 usually, the upright, vertical portion of a plant,
which transports substances to and from the leaves
10 internal plant root tissue forming a boundary between the cortex and the vascular tissue
12 vascular tissue that conducts organic solutes in
plants; contains sieve-tube cells and companion
cells
13 lateral meristem that produces secondary phloem and
secondary xylem (two words)
15 vascular tissue that transports water and mineral
solutes upward through the plant body; it contains
vessel elements and tracheids
16 undifferentiated embryonic tissue in the active
growth regions of plants
17 seed leaf for embryonic plant, providing nutrient
molecules for the developing plant before its mature leaves begin to photosynthesize
Down
2 in a plant leaf, the layer containing elongated cells
with many chloroplasts (two words)
3 in a plant leaf, the layer containing loosely packed,
irregularly spaced cells that increase the amount of
surface area for gas exchange (two words)
7 inner, thickest layer of a leaf consisting of palisade
and spongy; the site of most photosynthesis
8 lateral meristem that produces cork (two words)
9 nonwoody stem
11 extension of a root epidermal cell that collectively
increases the surface area for the absorption of water
and minerals (two words)
14 waxy layer covering the epidermis of plants that
protects the plant against water loss and diseasecausing organisms
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CHAPTER TEST
OBJECTIVE QUESTIONS
Do not refer to the text when taking this test.
1. Each is a mature tissue in plants EXCEPT
a. epidermal.
b. ground.
c. meristem.
d. vascular.
2. Select the incorrect association.
a. collenchyma—flexible support
b. parenchyma—unspecialized
c. sclerenchyma—tough and hard
d. sieve-tube member—mechanical strength
3. Select the correct association.
a. phloem—minerals
b. phloem—photosynthesis
c. xylem—sugar
d. xylem—water
4. The zone farthest from the root cap is the zone
of
a. cell division.
b. elongation.
c. maturation.
d. primary growth.
5. The root type in the carrot is the
a. adventitious root.
b. fibrous root.
c. taproot.
d. prop root.
6. The palisade mesophyll
a. stores food in the form of starch for the rest
of the plant.
b. absorbs water and minerals.
c. contains elongated cells where photosynthesis takes place.
d. opens to allow gases to move in and out.
7. The wood portion of a woody stem is composed
of
a. pith.
b. cambium.
c. bark.
d. secondary xylem.
e. secondary phloem.
8. Trace the path of water from the roots to the
leaves in a nonwoody plant.
a. root hairs→cortex→vascular tissue of
root→vascular bundles→leaf veins
b. root hairs→pith→xylem→phloem→
wood→leaf veins
c. cortex→endodermis→xylem→tracheids→
parenchyma→leaf veins
d. root hairs→sclerenchyma→vascular tissue
of root→cortex→leaf veins
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9. Stomata are
a. a type of transport tissue.
b. openings in leaf epidermis.
c. found in woody trees only.
d. a universal type of cell.
e. All of these are correct.
10. Which of these comparisons of monocots and
eudicots is NOT correct?
Monocots
Eudicots
a. net veined—parallel veined
b. one cotyledon—two cotyledons
c. scattered vascular bundles—circular pattern
d. flower parts in threes—flower parts in
fours/fives
11. A cross section through the zone of maturation
of a eudicot root would show
a. cells of the root cap.
b. the apical meristem.
c. transport tissues.
d. greatly elongated, undifferentiated cells.
e. All of these are correct.
12. Annual rings in woody stems are caused by an
increase in rings of the
a. primary phloem.
b. secondary phloem.
c. primary xylem.
d. secondary xylem.
13. The point of a stem at which leaves and/or buds
are attached is termed the
a. node.
b. internode.
c. lenticel.
d. endodermis.
e. plasmodesmata.
14. A leaf and a root both
a. photosynthesize.
b. store the products of photosynthesis in bad
times.
c. have vascular tissue.
d. have a double layer of epidermis.
15. What role does transpiration play in water transport?
a. no role
b. pushes the water
c. pulls the water
16. For transpiration to occur in the leaves,
a. water must exhibit cohesiveness.
b. the stomata must be open.
c. water must evaporate.
d. All of these are correct.
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17. Turgor pressure is important to
a. opening and closing of a stoma.
b. plant cell rigidity.
c. water flow in xylem.
d. Both a and b are correct.
e. All of these are correct.
18. During phloem transport, the sink has
a. the higher solute concentration, accounting
for why water flows to it.
b. the lower solute concentration, due to the active transport of sucrose out of it.
c. the higher solute concentration because that
is where sucrose is needed.
d. Both a and c are correct.
CRITICAL THINKING QUESTIONS
The introduction to this chapter is about the pitcher plant.
19. What type compound, in particular, do pitcher plants acquire from digesting insects? ________________________
20. Plants have a problem acquiring nitrogen because they cannot make use of what atmospheric gas? ____________
21. What mutualistic relationship allows plants, particularly legumes (e.g., beans), to acquire nitrogen
compounds? ________________________________________________________________________________________________
22. What major nutrient do plants acquire from the atmosphere? _________________________________________________
23. How do they acquire it? ____________________________________________________________________________________
Test Results: ______ number correct ÷ 23 = ______ × 100 = ______ %
EXPLORING
THE
INTERNET
ARIS, the Essentials of Biology website: http://www.mhhe.com/maderessentials
ARIS, the website for Essentials of Biology, offers access to a wide variety of tools to help students learn biological
concepts and to reinforce their knowledge. Online study aids such as practice quizzes, interactive activities, animations, labeling exercises, flashcards, and much more are organized according to the major sections of each chapter.
There is even an online tutorial service!
ANSWER KEY
CHAPTER KEY TERMS
a. meristem b. phloem c. eudicot d. xylem e. herbaceous f. node g. vascular bundle h. transpiration i.
monocot j. wood k. lateral bud l. internode
STUDY EXERCISES
1. a. anchors b. water c. minerals d. root hairs e. transport f. node g. photosynthesis h. water, sunlight, carbon
dioxide 2. a, b, c 3. a. fibrous root; holds soil b. taproot; stores food c. prop root; anchors plant
4.
Monocot
Eudicot
Parallel pattern
Net pattern
Scattered
In a ring
One
Two
In a ring
Phloem alternates
with xylem
5. a. 2 b. 3 c. 1 d. 2 e. 3 f. 3 6. a. T b. T c. F
d. F e. F f. F g. T h. T i. T j. T k. F l. F m. T
7. a. cuticle b. upper epidermis c. palisade mesophyll
d. leaf vein e. spongy mesophyll f. lower epidermis
g. leaf vein h. cuticle i. stomata j. palisade mesophyll
k. spongy mesophyll 8. a. epidermis b. cortex c. vascular bundle d. pith e. xylem, phloem 9. a. scattered b. ring 10. a. bark b. vascular cambium
c. wood d. cork e. phloem f. annual rings g. to produce
new secondary xylem and secondary phloem each year
h. annual rings, three years old 11. See Figure 20.13,
page 346, in text. 12. a. New cells are appearing. b.
Cells are getting longer. c. Cells are mature and specialized. 13. a. 4 b. 1 c. 3 d. 7 e. 6 f. 5
14. a. MA b. MA c. MI d. MI e. MA f. MI 15. a. root
nodules b. mycorrhizal 16. See Figure 20.17, page
349, in text. 17. a. Tracheids and vessel elements
b. root hairs c. energy causes water to evaporate.
d. Tension e. water column f. Cohesion and adhesion
g. Tension can only work if the water column is continuous. 18. The sun causes water to evaporate, and this
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creates a tension that pulls the water column, continuous
due to the cohesion of water molecules that adhere to the
sides of xylem. 19. a. epidermal cell b. nucleus
c. guard cell d. exits 20. a. turgor b. open 21. a.
Water is lost by transpiration. b. Carbon dioxide is being
absorbed. 22. See Figure 20.19, page 350, in text. 23.
a. Sieve-tube members b. Sieve-tube members are connected by strands of cytoplasm (plasmodesmata). c.
source d. Active transport e. Osmosis f. Positive pressure g. Active transport h. causes sugar to move from
area of higher to lower concentration i. sink 24. When
sugar is actively transported into phloem, water follows
by osmosis, creating a positive pressure. When sucrose
is actively transported out of sieve-tube elements, a gradient is established that causes sugar to flow from source
to sink.
KEYWORD CROSSWORD
1
2
E P I
D E R M I
3
S
4
P A R E N C H Y M A
A
5
L E A F
O
I
N
6
7
S T E M
E
A
G
Y
8
S
D
C
10
E N D O D E R M
P
E
H
S
M
Y
E
P
H
Y
15
X Y L
L
13
9
H
O
E
R
R
K
B
R
P H L O E M
C
C
H
O
A
Y
T
O
L
O
S
11
12
L
S
I
14
V A S C U L A R
L
U
H
E M
T
A
A
M
C A M B I
I
E
O
U M
S
U
16
M E R I S T E M
I
C
R
17
C O T Y L E D O N
E
CHAPTER TEST
1. c 2. d 3. d 4. c 5. c 6. c 7. d 8. a 9. b
10. a 11. c 12. d 13. a 14. c 15. c 16. d
17. d 18. b 19. nitrogen compounds 20. nitrogen
(N2) 21. root nodules 22. carbon dioxide 23. through
stomata
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