EXPLORING LIFE

EXERCISE 8: VEGETATIVE BODY OF ANGIOSPERMS

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Exercise 8: Vegetative Body of Angiosperms Workbook Contents Corresponding Section on CD Vocabulary Key Concepts Introduction 1. Introduction Roots 2. Roots Form and Function 2A. Form and Function Anatomy of Primary Root Tips 2B. Anatomy of Primary Roots Cross Section of Primary Dicot Root 2C. Primary Dicot Roots Cross Section of Monocot Root 2D. Monocot Roots Cross Section of Woody Dicot Root 2E. Woody Dicot Roots Stems 3. Stems Primary Dicot Stem 3A. Primary Dicot Monocot Stem 3B. Monocot Woody Dicot Stem 3C. Woody Dicot Leaves 4. Leaves Leaf Morphology 4A. Leaf Morphology Leaf Structure 4B. Leaf Structure 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

xylem

endodermis

phloem

pericycle

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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.

It can also divide and produce new cells that function like a cortex. 30. Label the structures of the woody dicot root cross-section:

phloem fibers

secondary xylem

secondary phloem

periderm

epidermis

primary xylem

cambium

pericycle

cortex

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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

apical meristem

meristematic tissue

node

internode

bud

leaf gap

Definition

allows growth in length and width of leaves

area between growing points

forms new leaves, flowers, or branches

growing cells at tip of stem

growing point along the stem

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?

34. Match the structures with their location on the apical meristem and with their definition.

Structure

tunica

corpus

central mother cells

flank meristems

rib meristems

Definition

gives rise to the epidermis & leaves

cells can divide in any plane

cells with many vacuoles

gives rise to the cortex

gives rise to the stele

Width of Area Number of Cells

Leaf tissue near the tip in/cm

Leaf tissue further down in/cm

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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? 38. Like leaves, do stems have stomata? What structure protects them from predation?

39. Match the following structures with their location on the diagram.

Younger Stem

xylem

phloem

vascular bundle

cambium

cortex

pith

epidermis

Older Stem

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:

heartwood

dead ray parenchyma

living ray parenchyma

youngest xylem

oldest xylem

sap wood

vascular cambium

phloem

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

palisades mesophyll

chloroplast

phloem

spongy mesophyll

guard cells

epidermis

nucleus

xylem

bundle sheath cells

air chamber

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

protective layer

abscission layer

Descriptions

enzymes digest pectin and cellulose fibers in cell walls

has thick coat of suberin

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

bud scale

bud scale scars

annual growth

leaf scar

lenticel

formed when buds grow and scales fall off

formed when the leaf falls off

gives rise to new branch growth

measured from one ring of bud scale scars to the next

provides for gas exchange in woody structures

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

thick fleshy stems, thinner leaves

underground storage stem

surface stem that produces new plantlets

modified branches arising from leaf axil

modified leaves devoid of chlorophyll

epidermal projections that are easily broken off

leaf-like, photosynthesizing stems

modified leaves or stems for grasping & support

structures for capturing and digesting insects

bulb

cladophyll

corm

(modified leaves)

prickle

spine

stolon

tendril

thorn

tuber

asparagus

cacti

gladiolus & tulip

hawthorn & locust

ivy

onion

potato

roses

strawberry & potato

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 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.

Num

ber

Structure Lette

r

Description/Function Num

ber

+ L

ette

r

Plan

t(s)

1 abscission layer A cells that control the opening and closing of stomata 1F WD 2 apical meristem B cells that minimize exposed leaf surface area when plant loses water 3 bark C cork cambium; meristematic; produces cork and phelloderm 4 buds D formed from pericycle; allow gas exchange 5 bulliform cells E growing points along stems where leaves originate 6 bundle sheath cells F layer of cells at stem-leaf interface that contain enzymes that digest pectin 7 cork G layer of cells at stem-leaf interface that provide a thick coat of suberin 8 cortex H layer of cells that surround vascular bundles; play role in C4 photosynthesis 9 cuticle I non-growing regions between nodes

10 endodermis J opening in leaf or some stems through which gas exchange occurs 11 epidermis K outermost layer of cells; often protected by the cuticle 12 fibrous root L outermost layer of stele; usually one cell thick; gives rise to lateral roots 13 flank meristem M produced from phellogen as daughter cells are pushed to inside; living tissue 14 guard cells N produced from phellogen as daughter cells are pushed to outside; dead tissue 15 heartwood O projection of an epidermal cell where water and mineral absorption occurs 16 intercalary meristem P region in center of root in which vascular tissue is arranged in concentric circles 17 internode Q region in which cells differentiate 18 lenticel R region in which central vacuole expands and lengthens cells 19 lignin S region of a woody stem that conducts water and has living ray parenchyma 20 meristematic region T region of a woody stem that contains dead tissue 21 mucigel U region of a woody stem where most living tissue is found 22 node V region of cell division and production 23 palisades mesophyll W region of cells between the cortex and the vascular bundles 24 pericycle X region of growth at the tip of a shoot 25 periderm Y region of growth not at the tip of a shoot but near the base of leaves 26 phelloderm Z region outside of endodermis; stores starch; moves water from epidermis to stele 27 phellogen AA region within meristematic region that does not produce cells but hormones 28 phloem BB root system that fills less space but can grow deeper 29 pith CC root system that fills more space but does not go as deep 30 procambial strands DD site of geotropic response; lubricates root tip; protects meristematic region 31 protective layer EE substance found in secondary cell walls 32 quiescent region FF substance that lubricates root tip movement 33 region of cell maturation GG substance that prevents water movement between cells 34 region of elongation HH tissue in center of leaf containing parallel cells with many chloroplasts 35 rib meristem II tissue in center of leaf that is less organized and toward underside of leaf 36 root cap JJ tissue layer that produces cork 37 root hair KK tissue that develops into the cambium 38 sapwood LL tissue that gives rise to new branches, leaves or flowers 39 spongy mesophyll MM tissue that gives rise to the cortex 40 stoma NN tissue that gives rise to the epidermis 41 suberin OO tissue that gives rise to the stele 42 tap root PP tissue that gives rise to xylem and phloem 43 tunica QQ tissue that transports dissolved substances from leaves to rest of plant 44 vascular cambium RR tissue that transports water from roots to rest of plant 45 xylem SS waxy, protective covering of the epidermis

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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 b. herbaceous dicot root c. woody dicot root

d. monocot stem e. herbaceous dicot stem f. woody dicot stem

g. monocot leaf h. evergreen dicot leaf i. deciduous dicot leaf

4. Label the structures of this root cross-section. What type of plant does it belong to?