EXPLORING LIFE
EXERCISE 8:
VEGETATIVE BODY
OF ANGIOSPERMS
Exercise 8: Vegetative Body of Angiosperms
Workbook Contents
Corresponding Section on CD
Vocabulary
Key Concepts
Introduction
1. Introduction
Roots
Form and Function
Anatomy of Primary Root Tips
Cross Section of Primary Dicot Root
Cross Section of Monocot Root
Cross Section of Woody Dicot Root
2. Roots
2A. Form and Function
2B. Anatomy of Primary Roots
2C. Primary Dicot Roots
2D. Monocot Roots
2E. Woody Dicot Roots
Primary Dicot Stem
Monocot Stem
Woody Dicot Stem
3. Stems
3A. Primary Dicot
3B. Monocot
3C. Woody Dicot
Leaf Morphology
Leaf Structure
4. Leaves
4A. Leaf Morphology
4B. Leaf Structure
Stems
Leaves
Shoot Modifications
5. Shoot Modifications
Summary & Review
Vocabulary
Amyloplast - Starch-bearing plastid
Apical meristem - Meristem found at the tips of branches and roots
Axil - Angle between stem and leaf
Bulb - Underground storage stem characterized by having fleshy leaves, e.g., an onion
Bulliform cells - Large cells found in the epidermis of grass leaves that cause the leaf to roll and unroll around
the long axis of the leaf
Bundle sheath cells - Layer of mesophyll cells surrounding the veins in C4 plants
Casparian strips - Suberin found on the radial walls of endodermis. Named for Robert Caspary, a German
botanist.
Central mother cells - Large highly vacuolated cells found beneath the tunica of shoot apical meristems
Cladophyll - Modified stem that appears to be a leaf
Corm - An upright underground storage stem with relatively thin leaves
Corpus - The main body of a shoot apical meristem. The corpus is often divided into the rib and flank
meristems.
Cortex - Ground tissue found between the epidermis and vascular tissue of stems and roots
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Endodermis - Innermost layer of the root cortex; the endodermis has Casparian strips that force water from the
apoplast into the symplast
Exarch development - The pattern of root xylem development in which the protoxylem develops exterior to the
metaxylem
Internode - The portion of a stem between successive nodes
Kranz anatomy - Ring of large mesophyll cells surrounding a vein in the leaves of C4 plants
Mesophyll - Ground tissue in the middle of the leaf
Metaxylem - Primary xylem elements that differentiate after the protoxylem. Metaxylem elements have a more
complete secondary cell wall.
Mucigel - Slime that covers some roots
Nodes - The portion of a stem where leaves or modified leaves arise; a growing point
Palisades mesophyll - Column-like chlorenchyma found below the upper epidermis of leaves
Pericycle - A root lateral meristem interior to the endodermis. The pericycle gives rise to lateral roots,
phellogens and portions of the vascular cambium.
Phyllotaxis - The arrangement of leaves along the stem
Pinnate - Venation pattern with a single primary vein and smaller veins branching to the sides
Prickle - Sharp epidermal projection such as roses have
Protoxylem - The first primary xylem elements to differentiate
Quiescent region - A region in the root apical meristem where the cells divide infrequently
Reticulate venation - A pattern of netlike small veins found in dicot leaves
Rootcap - A group of cells that cover and protect the root tip. The rootcap is the site of the gravitropic response
that causes roots to bend towards the center of the earth.
Spine - Pointed leaf as cacti have
Spongy mesophyll - Loosely organized chlorenchyma between the palisades mesophyll and lower epidermis of
some leaves
Stolon - Stem that grows along the surface of the ground and may be involved in asexual reproduction as in
strawberry plants
Suberin - Fatty material found in cork cells and the Casparian strips of endodermis
Tendril - Leaf or stem modified to hold on to other plants or objects as grape vines do
Tuber - Relatively large underground storage stem, e.g., a potato
Tunica - Outermost layer of the shoot apical meristem
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KEY CONCEPTS
This section of the workbook is set up to help you note important
information relating to the key concepts of this exercise and then organize
and summarize the information in order to develop a synthesis and prepare
for a review. As you complete this exercise, you will focus on the
characteristics of various plant tissue types so that you will be able to
distinguish:
Roots, Shoots, and Leaves
1. What are the structures of various root/shoot/leaf types?
2. How do these structures function?
3. How do these structures grow/form?
Shoot Modifications
4. What are some of the various shoot modifications?
5. What are their functions?
6. How do we use these characteristics to distinguish among plant
groups?
The first several pages are questions that can be answered by following the
progression of slides and paying careful attention to the information, both
visual and audio. These questions should be read in advance of each
section so that you can be better prepared to answer them by knowing
what you are looking for. The underlined subheadings correspond to the
sections of the exercise as outlined in the main menu.
The subsequent pages are designed to help you summarize and synthesize
the pertinent information to answer the questions posed above. These are
followed by a review quiz.
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VEGETATIVE BODY OF ANGIOSPERMS
Introduction
1. Match each of the plants with the group to which it belongs:
First-Level Groups
Second-Level Groups
Plants
dicotyledones
herbaceous dicots
oak
monocotyledones
woody dicots
daisy
lily
Roots
Form and Function
2. True or False: All roots are found underground.
3. List at least four functions of roots:
4. True or False: Root systems are extensive so that they have a greater surface area for absorption.
True or False: Most absorption takes place along the length of each root.
5. Describe how the branching growth of a root system increases its surface area, using the scale reduction
model. You may use words or a labeled diagram for your description:
6. Match each diagram to the root system, definition, and plant group in which it is most commonly found:
Root Diagrams
Root System
Definition
Plant Group
fibrous
fills less space but can grow deeper
monocots
tap
fills more space but does not go as deep
dicots
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KEY CONCEPTS
7. As the ratio of water and nutrient absorption in roots / shoots must be balanced with photosynthesis
occurring in the roots / shoots, aquatic plants tend to have fewer / larger roots and fewer /
larger shoots, while desert plants have larger / smaller roots and larger / smaller shoots.
EC Explain how the information in Question #7 can help gardeners:
Anatomy of Primary Root Tips
8. Match the root structures to the diagram of the herbaceous dicot root and to each of their functions:
Root Structures
Functions
absorb water and nutrients
root hair
cell division; produces new cells
cells differentiate
region of maturation
cells get longer
cells rarely divide
region of cell elongation
central vacuole stretches cell wall
geotropic response
meristematic region
is a projection of an epidermal cell
local source of hormones
quiescent region
lubricates with mucigel & old cells
protect meristematic region
root cap
region where root hairs are found
Cross Section of Primary Dicot Root
9. Match the tissues with their location on the diagram:
parenchyma
phloem
xylem
pericycle
endodermis
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VEGETATIVE BODY OF ANGIOSPERMS
10. The first developing vessels are called the metaxylem / protoxylem and the secondary cell wall
material begins forming in simple rings / spirals and then rings / spirals. The vessels with fully
developed secondary cell walls form the metaxylem / protoxylem.
11. Add labels for protoxylem and metaxylem to Question #9 and connect them to the diagram.
12. exarch development = development from the center to the outside / outside to the center. This type of
development is found in roots / stems.
13. Add labels for sieve tube members and companion cells to Question #9 and connect them to the diagram.
14. Most dicots have a cambium / cortex between their xylem and phloem. Some have an abundance
and use it to produce excessive amounts of what type of tissue?
EC Look up the term stele. What is the definition? What tissues are part of the stele?
15. What are the functions of the pericycle? List at least four:
16. Describe the composition, location and function of suberin:
17. Add a label for cortex to Question #9 and connect it to the diagram. What is the function of cells in this
region? List at least two:
18. The outermost layer of the root is the endodermis / epidermis. What structure is observed to “grow”
from certain epidermal cells?
19. Circle the following structures and organisms that are part of the rhizosphere and assist in plant functions:
algae
bacteria
fungi
meristematic cells
mucigel
parenchyma tissue
protozoa
root cap cells
root hairs
small stones
soil particles
suberin
EC Describe the functions of some of these components in relation to the plant and its roots:
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KEY CONCEPTS
20. Diagram and label the three paths water can take from the soil into the xylem:
Cross Section of Monocot Root
21. At the center of the dicot root is the pith / xylem, while at the center of the monocot root is the pith /
xylem.
22. Label these structures on the monocot root cross-section:
epidermis
cortex
pericycle
phloem
xylem
pith
23. Circle the following statements that indicate the principle differences between dicot and monocot roots:
a. Dicot and monocot roots have very different tissues.
b. Dicot and monocot roots have different arrangements of tissues.
c. Dicot and monocot roots derive from different tissues in the developing plant.
d. Dicot and monocot roots have different paths of development (i.e., exarch vs. endarch).
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VEGETATIVE BODY OF ANGIOSPERMS
Cross Section of Woody Dicot Root
24. Label the tissues in this woody dicot root cross-section:
procambial strands
primary xylem
primary phloem
pericycle
endodermis
25. Circle the two tissues that give rise to the vascular cambium:
parenchyma
pericycle
periderm
phloem
procambial strands
26. The daughter cells that get pushed inward form the phloem / xylem while those that are pushed
outward become the phloem / xylem.
27. Circle the two tissues that split as a result of secondary growth:
cork cambium
cortex
endodermis
epidermis
periderm
28. Pericycle / Periderm is the new tissue formed when the primary tissues split. Then, the cork cambium
or phelloderm / phellogen is formed. This lateral meristem divides. The cells pushed to the outside of
the plant become the cork / cortex. These cells are heavily chitinized / lignified
and are dead /
living when mature. The cells pushed to the interior become the phellem / phelloderm.
29. The periderm may form loosely packed structures called
that allow gas exchange.
cells that function like a cortex.
It can also divide and produce new
30. Label the structures of the woody dicot root cross-section:
phloem fibers
primary xylem
secondary xylem
cambium
secondary phloem
pericycle
periderm
cortex
epidermis
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KEY CONCEPTS
Stems
Primary Dicot Stem
31. Match each structure to the diagram and its definition. In the list, circle the structure that has cells that do
not divide. Which structure(s) do roots lack?
On the diagram, circle
the tissue that gives rise to the vascular cambium.
Structure
Definition
apical meristem
allows growth in length and width of leaves
meristematic tissue
area between growing points
node
forms new leaves, flowers, or branches
internode
growing cells at tip of stem
bud
growing point along the stem
leaf gap
space in “plumbing” of plant stem
32. Leaf gaps occur in steles with a periderm / pith. Describe how water and dissolved substances get
“around” the leaf gap:
33. Record the width and number of cells of each leaf area below. Is the difference in widths of the leaves
primarily a result of differences in cell number or cell size?
Width of Area Number of Cells
Leaf tissue near the tip
in/cm
Leaf tissue further down
in/cm
34. Match the structures with their location on the apical meristem and with their definition.
Structure
Definition
tunica
gives rise to the epidermis & leaves
corpus
cells can divide in any plane
central mother cells
cells with many vacuoles
flank meristems
gives rise to the cortex
rib meristems
gives rise to the stele
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VEGETATIVE BODY OF ANGIOSPERMS
35. What would happen if you removed the structure pictured in Question #34?
What makes grasses special?
36. List the three functions of stems:
What is important about how the structures are stems are positioned?
37. What is the benefit of arranging leaves in a Fibonacci spiral?
What structure protects them from predation?
38. Like leaves, do stems have stomata?
39. Match the following structures with their location on the diagram.
Younger Stem
Older Stem
xylem
phloem
vascular bundle
cambium
cortex
pith
epidermis
Monocot Stem
40. Label the following structures on the monocot stem cross-sections:
phloem
companion cell
xylem
sclerenchyma/fibers
parenchyma
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KEY CONCEPTS
41. Does this monocot stem have a real pith?
Does it have a permanent cambium?
42. Give an example of a monocot tree and describe its support structures:
Woody Dicot Stem
43. Using the diagram, explain the formation of growth rings in woody dicots:
44. Match the following tissues and regions with the woody dicot stem cross-section:
oldest xylem
heartwood
sap wood
dead ray parenchyma
vascular cambium
living ray parenchyma
phloem
youngest xylem
bark
45. Are there any living tissues in the heartwood?
Is water conducted through the sapwood?
46. What happens to the oldest phloem?
47. Where is most of the living tissue in a woody dicot stem found?
48. What does a woody dicot stem have instead of stomata?
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VEGETATIVE BODY OF ANGIOSPERMS
Leaves
Leaf Morphology
EC Define the term morphology:
49. What is the primary function of leaves in most angiosperms?
50. The typical monocot leaf is feather-like / strap-like. The vascular bundles are arranged in a network
/ parallel. The stomata are in rows / scattered.
51. Label the following leaves with these terms (some may be used more than once): simple leaf, compound
leaf, leaflet, blade or lamina, petiole, pinnate venation, reticulate (net) venation, palmate venation
52. What is important about the shape and arrangement of leaves and leaf margins?
53. Label each type of leaf arrangement (phyllotaxis) on the stem: alternate or spiral, opposite, whorled
Labels:
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KEY CONCEPTS
Leaf Structure
54. Match the following structures and tissues with the leaf cross-section. You may have to return to this
question periodically as you go through this section of the exercise.
cuticle
epidermis
palisades mesophyll
nucleus
chloroplast
xylem
phloem
bundle sheath cells
spongy mesophyll
air chamber
guard cells
stoma
55. Describe the structure and function of Kranz anatomy. Label the diagram as a part of your description.
What type of plants have Kranz anatomy?
EC Discuss the process of photosynthesis in a C4 plant. Be sure to give the location of each step. You may use
a labeled diagram:
56. The amount of glucose ultimately produced depends on the existence of
Which type of plant has more vascular bundles – C3 or C4?
Which type of plant do you think is more efficient?
Explain your answer:
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.
VEGETATIVE BODY OF ANGIOSPERMS
57. Describe the structure and function of bulliform cells. What type of plant are they found in?
You may use one or more labeled diagrams for your description.
58. Match the following layers with their location on the diagram and their descriptions:
Layers
Descriptions
enzymes digest pectin and cellulose fibers in cell walls
protective layer
has thick coat of suberin
abscission layer
isolates leaf, seals off stem
parenchyma in xylem bulge, restricting water
EC Why do deciduous trees in temperate regions lose their leaves? What environmental conditions initiate this?
59. Match these structures to their location on the diagram of the woody dicot twig and to their description:
apical bud
formed when buds grow and scales fall off
bud scale
formed when the leaf falls off
bud scale scars
gives rise to new branch growth
annual growth
measured from one ring of bud scale scars to the next
leaf scar
provides for gas exchange in woody structures
lenticel
surround and protect buds
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KEY CONCEPTS
Shoot Modifications
60. Match each of the following stem modifications to their description and example plant(s):
Description
Stem Modification
Example Plants
thick cone-shaped stem, thick fleshy leaves
bulb
asparagus
thick fleshy stems, thinner leaves
cladophyll
cacti
underground storage stem
corm
gladiolus & tulip
surface stem that produces new plantlets
(modified leaves)
hawthorn & locust
modified branches arising from leaf axil
prickle
ivy
modified leaves devoid of chlorophyll
spine
onion
epidermal projections that are easily broken off
stolon
potato
leaf-like, photosynthesizing stems
tendril
roses
modified leaves or stems for grasping & support
thorn
strawberry & potato
structures for capturing and digesting insects
tuber
sundew
SUMMARY & REVIEW
1. In their organs, tissues and functions, what are the major distinctions between:
a. monocots and dicots:
b. woody and herbaceous dicots:
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VEGETATIVE BODY OF ANGIOSPERMS
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1F
Plant(s)
Structure
Description/Function
abscission layer
A cells that control the opening and closing of stomata
apical meristem
B cells that minimize exposed leaf surface area when plant loses water
bark
C cork cambium; meristematic; produces cork and phelloderm
buds
D formed from pericycle; allow gas exchange
bulliform cells
E growing points along stems where leaves originate
bundle sheath cells
F layer of cells at stem-leaf interface that contain enzymes that digest pectin
cork
G layer of cells at stem-leaf interface that provide a thick coat of suberin
cortex
H layer of cells that surround vascular bundles; play role in C4 photosynthesis
cuticle
I non-growing regions between nodes
endodermis
J opening in leaf or some stems through which gas exchange occurs
epidermis
K outermost layer of cells; often protected by the cuticle
fibrous root
L outermost layer of stele; usually one cell thick; gives rise to lateral roots
flank meristem
M produced from phellogen as daughter cells are pushed to inside; living tissue
guard cells
N produced from phellogen as daughter cells are pushed to outside; dead tissue
heartwood
O projection of an epidermal cell where water and mineral absorption occurs
intercalary meristem
P region in center of root in which vascular tissue is arranged in concentric circles
internode
Q region in which cells differentiate
lenticel
R region in which central vacuole expands and lengthens cells
lignin
S region of a woody stem that conducts water and has living ray parenchyma
meristematic region
T region of a woody stem that contains dead tissue
mucigel
U region of a woody stem where most living tissue is found
node
V region of cell division and production
palisades mesophyll
W region of cells between the cortex and the vascular bundles
pericycle
X region of growth at the tip of a shoot
periderm
Y region of growth not at the tip of a shoot but near the base of leaves
phelloderm
Z region outside of endodermis; stores starch; moves water from epidermis to stele
phellogen
AA region within meristematic region that does not produce cells but hormones
phloem
BB root system that fills less space but can grow deeper
pith
CC root system that fills more space but does not go as deep
procambial strands
DD site of geotropic response; lubricates root tip; protects meristematic region
protective layer
EE substance found in secondary cell walls
quiescent region
FF substance that lubricates root tip movement
region of cell maturation GG substance that prevents water movement between cells
region of elongation
HH tissue in center of leaf containing parallel cells with many chloroplasts
rib meristem
II tissue in center of leaf that is less organized and toward underside of leaf
root cap
JJ tissue layer that produces cork
root hair
KK tissue that develops into the cambium
sapwood
LL tissue that gives rise to new branches, leaves or flowers
spongy mesophyll
MM tissue that gives rise to the cortex
stoma
NN tissue that gives rise to the epidermis
suberin
OO tissue that gives rise to the stele
tap root
PP tissue that gives rise to xylem and phloem
tunica
QQ tissue that transports dissolved substances from leaves to rest of plant
vascular cambium
RR tissue that transports water from roots to rest of plant
xylem
SS waxy, protective covering of the epidermis
Number
+ Letter
Letter
Number
Match the structure with its description by placing the number and letter in the column provided. Then label the plant group in
which it is found - M = monocot, HD = herbaceous dicot, WD = woody dicot. The first one has been done for you.
WD
SUMMARY AND REVIEW
3. On a separate sheet of paper, describe the structures and functions (particularly characteristic ones) of each
of the following organs. You may use labeled diagrams.
a. monocot root
d. monocot stem
g. monocot leaf
b. herbaceous dicot root
e. herbaceous dicot stem
h. evergreen dicot leaf
c. woody dicot root
f. woody dicot stem
i. deciduous dicot leaf
4. Label the structures of this root cross-section. What type of plant does it belong to?
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