C3, C4 and CAM Plant Metabolism

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CAM Plants interface

CAM Plants vs Regular Plants – Stomata Lab

Comparing Plant Adaptations to Different Environments

Name: _____________________________ Date: __________ Period: ____

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Purpose

To investigate how CAM (Crassulacean Acid Metabolism) plants have adapted their stomata behavior differently than regular plants to survive in hot, dry environments.

Background Information

Regular Plants (C3 Plants)

Most plants you’re familiar with – like trees, vegetables, and houseplants – are called C3 plants. They:

• Open stomata during the DAY when there’s light for photosynthesis
• Take in CO₂ during the day and use it immediately
• Close stomata at NIGHT to conserve water
• Work well in normal environments with adequate water

The Problem: In hot, dry environments, opening stomata during the hot day causes massive water loss through transpiration!

CAM Plants – Desert Survivors!

CAM plants include cacti, succulents, pineapples, and many desert plants. They evolved a clever solutionA homogeneous mixture of two or more substances.:

• Open stomata at NIGHT when it’s cool (less water loss!)
• Store the CO₂ as an acid in their cells overnight
• Close stomata during the DAY (preventing water loss in the heat)
• Use the stored CO₂ for photosynthesis during the day with stomata closed

CAM stands for: Crassulacean Acid Metabolism (named after the Crassula plant family where it was discovered)

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Materials

• Computer or tablet with internet access
• Interactive stomata simulation (provided by teacher)
• This lab handout
• Colored pencils (optional)

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Procedure

You will use the interactive simulation to test how regular plants and CAM plants respond to different environmental conditions. The simulation shows you when stomata are open or closed based on conditions you set.

Part 1: Regular Plant Behavior

Test the following scenarios for a REGULAR PLANT and record whether stomata are OPEN or CLOSED:

Scenario	Light	Water	Temperature	Humidity	Stomata State (Open/Closed)
1. Normal day	Bright	Adequate	Normal	Normal
2. Hot desert day	Bright	Drought	Hot	Dry
3. Cool morning	Bright	Adequate	Cool	Humid
4. Night time	Dark	Adequate	Normal	Normal
5. Drought conditions	Bright	Drought	Normal	Normal

Questions:

1. Under which conditions did the regular plant’s stomata stay open?
2. What happened when you created hot, dry, drought conditions during the day?
3. Why would this be a problem for a plant living in the desert?

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Part 2: CAM Plant Behavior

Now imagine you’re testing a CAM plant (like a cactus). CAM plants have OPPOSITE behavior to regular plants!

For CAM plants:

• Stomata OPEN at NIGHT (when it’s cool and humid)
• Stomata CLOSED during DAY (to prevent water loss in heat)

Fill in the table for how a CAM plant would behave:

Scenario	Light	Water	Temperature	Humidity	CAM Plant Stomata State
1. Normal day	Bright	Adequate	Normal	Normal
2. Hot desert day	Bright	Drought	Hot	Dry
3. Cool morning	Bright	Adequate	Cool	Humid
4. Night time	Dark	Adequate	Normal	Normal
5. Night in desert	Dark	Drought	Cool	Normal

Questions:

1. When do CAM plants open their stomata? Why is this an advantage in the desert?
2. How can CAM plants do photosynthesis during the day if their stomata are closed?
3. What is the main benefit of being a CAM plant in a hot, dry environment?

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Part 3: Direct Comparison

Complete the comparison table:

Feature	Regular (C3) Plants	CAM Plants
When stomata open
When CO₂ is taken in
When photosynthesis occurs
Water loss strategy
Best environment
Example plants	Oak tree, spinach, wheat	Cactus, aloe vera, pineapple

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Analysis Questions

1. Imagine it’s noon in the Sonoran Desert (hot, dry, bright sun). Draw or describe what’s happening with stomata in both plant types: Regular Plant: CAM Plant:
2. Why don’t ALL plants use the CAM pathway if it saves so much water? (Hint: Think about the extra steps and energy needed to store CO₂ overnight)
3. A student says: “CAM plants don’t need water at all!” Is this correct? Explain.
4. Look at the two scenarios below and predict which plant would survive better:Scenario A: Rainforest (abundant water, warm, humid, lots of light)
   • Better plant: ___________________
   • Reason: _____________________________________________________________
   Scenario B: Desert (scarce water, hot days, cool nights, intense sun)
   • Better plant: ___________________
   • Reason: _____________________________________________________________
5. A farmer wants to grow crops in a very dry region. Based on what you learned, what advice would you give them about plant selection?
6. CAM plants grow more slowly than regular plants. Why might this be?

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Data Analysis: Water Loss Comparison

Hypothetical Data: Scientists measured water loss in both plant types over 24 hours in desert conditions.

Time Period	Regular Plant Water Loss	CAM Plant Water Loss
6 AM – 12 PM (Morning)	45 mL	5 mL
12 PM – 6 PM (Afternoon)	60 mL	8 mL
6 PM – 12 AM (Evening)	10 mL	15 mL
12 AM – 6 AM (Night)	5 mL	20 mL
TOTAL	120 mL	48 mL

Questions:

1. During which time period does the regular plant lose the most water? Why?
2. When does the CAM plant lose the most water? Why is this time better?
3. Calculate the percentage of water saved by the CAM plant compared to the regular plant: Calculation: ___________________________________________________________ Percentage saved: ___________
4. Create a bar graph comparing total water loss between the two plant types: (Use the space below to draw your graph with labeled axes)

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Real-World Applications

Research one of these CAM plants and answer the questions:

Choose one: 🌵 Cactus | 🍍 Pineapple | 🪴 Jade Plant | 🌿 Agave

My plant: _________________________

1. Where does this plant naturally grow?
2. What specific adaptations does it have besides CAM photosynthesis?
3. How do humans use this plant?

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Conclusion

Write a paragraph (6-8 sentences) that:

• Explains the main difference between regular and CAM plant stomata behavior
• Describes why CAM is an adaptation to hot, dry environments
• Discusses the trade-offs of using CAM photosynthesis
• Gives an example of when CAM is advantageous and when it’s not

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Extension Challenge: C4 Plants

There’s actually a THIRD type of photosynthesis called C4 (used by corn, sugarcane, and many grasses). Research C4 plants and answer:

1. How is C4 photosynthesis different from both C3 and CAM?
2. What advantage does C4 give plants?
3. Why are many important crop plants C4 plants?

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Teacher Notes:

This lab works in two ways:

1. With the interactive simulation:
   • Students test scenarios on the regular plant simulator
   • They manually predict/determine CAM plant behavior (opposite pattern)
   • Reinforces understanding through comparison
2. Time required: 45-60 minutes

Key teaching points:

• CAM = temporal separation (day vs night)
• Trade-off: water conservation vs. slower growthAn increase in size and number of cells.
• Evolution of different strategies for different environments
• Not all adaptations are “better” – they’re suited to specific conditions

Answers to key questions:

• CAM plants open stomata at night when it’s cooler = less water loss
• They store CO₂ as malic acid in vacuoles overnight
• Use stored CO₂ during day for photosynthesis with stomata closed
• Regular plants grow faster because they don’t need extra steps to store CO₂
• CAM plants survive better in deserts; regular plants in normal environments

Extension: Can show video of CAM plant stomata under microscope opening at night

Leaf Chromatography Lab

Separating Plant Pigments

Name: _____________________________ Date: __________ Period: ____

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Purpose

To separate and identify the different pigments found in plant leaves using paper chromatography.

Background Information

Leaves aren’t just green! While chlorophyll (the green pigment) is the most visible, leaves actually contain several different pigments. These include:

• Chlorophyll a & b (green) – absorbs light for photosynthesis
• Carotenoids (yellow/orange) – helps capture light energy
• Xanthophylls (yellow) – protects the plant from too much light

In fall, chlorophyll breaks down and we can finally see the other colors that were hidden! In this lab, you’ll use chromatography to separate these pigments and see all the colors in a green leaf.

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Materials (per group)

• Fresh green leaves (spinach works great!)
• Coffee filter strips (cut into strips about 2 cm wide and 10 cm long)
• Rubbing alcohol (isopropyl alcohol, 70% or higher)
• Small clear cup or beaker
• Coin or spoon
• Pencil
• Ruler
• Plastic wrap or foil

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Safety Rules

⚠️ READ BEFORE STARTING:

• Rubbing alcohol is flammable – keep away from flames
• Do not drink the alcohol or get it in your eyes
• Wash your hands after the lab
• Clean up any spills immediately
• Tell your teacher if you break any glassware

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Procedure

Step 1: Prepare your leaf sample

1. Place a leaf on a coffee filter strip about 3 cm from the bottom
2. Use the edge of a coin to firmly rub and grind the leaf across the filter
3. Keep rubbing until you have a dark green line of pigment on the filter
4. Let it dry for 1 minute, then repeat 2-3 more times to make the line darker

Step 2: Set up your chromatography

1. Pour rubbing alcohol into your cup to a depth of about 1 cm (just enough to cover the bottom)
2. Use a pencil to poke a small hole at the top of your filter strip
3. Rest the pencil across the top of the cup so the filter hangs down into the alcohol
4. IMPORTANT: The green pigment line should be ABOVE the alcohol level, not touching it!
5. Cover the top of the cup with plastic wrap or foil

Step 3: Wait and observe

1. Watch as the alcohol travels up the filter paper (this is called capillary action)
2. The alcohol will carry the pigments with it, but different pigments travel at different speeds
3. Wait about 10-15 minutes until the alcohol has traveled near the top of the strip
4. Remove the strip and let it dry

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Data Collection

Draw your chromatography results below:

(Draw a rectangle to represent your filter strip and color in the bands you see)

Colors I observed (from bottom to top):

Distance traveled by alcohol (solvent front): ________ cm

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Analysis Questions

1. What was the purpose of rubbing the leaf multiple times on the filter paper?
2. Why do you think we covered the cup with plastic wrap?
3. Which pigment traveled the farthest up the paper? Why do you think this happened?
4. Why don’t we normally see the yellow and orange pigments in leaves during the summer?
5. How does this lab help explain why leaves change color in the fall?

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Conclusion

Write 3-4 sentences summarizing what you learned about leaf pigments from this lab.

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Teacher Notes: This lab takes about 30-40 minutes total. Best results with fresh spinach leaves or other dark green leaves. Can use nail polish remover (acetone) instead of rubbing alcohol for faster results, but alcohol is safer for 9th graders.

Celery Transpiration Lab

Observing Water Transport in Plants

Name: _____________________________ Date: __________ Period: ____

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Purpose

To observe how water moves through a plant’s vascular system (xylem) and to demonstrate the process of transpiration.

Background Information

Plants need to move water from their roots all the way up to their leaves – sometimes over 100 feet high! This happens through special tube-like tissues called xylem. Water moves up through the plant due to:

• Transpiration – water evaporating from leaves creates a “pull” that draws more water up from the roots
• Capillary action – water moleculesGroups of atoms bonded together. stick to the xylem walls and to each other
• Root pressureThe force exerted by gases in the respiratory system, affecting airflow and gas exchange. – roots push water upward

In this lab, you’ll use food coloring to trace the path of water through celery, which will help you see the xylem tissues that normally carry water invisibly through the plant.

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Materials (per group)

• Fresh celery stalk with leaves (pale/light green works best)
• Clear cup or beaker
• Water
• Food coloring (red or blue works best)
• Ruler
• Sharp knife or scissors (teacher will help with cutting)
• Paper towels

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Safety Rules

⚠️ READ BEFORE STARTING:

• Only the teacher will use sharp knives
• Wipe up any water spills immediately to prevent slipping
• Do not drink the colored water
• Wash your hands after handling celery

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Procedure

Day 1 – Setup (15 minutes)

1. Fill your cup with water to about 5 cm deepAway from the surface of the body.
2. Add 10-15 drops of food coloring to the water and stir
3. Have your teacher cut the bottom 2 cm off your celery stalk at an angle (this creates a fresh cut for better water absorption)
4. Immediately place the celery in the colored water (cut end down)
5. Make sure the leaves are above the rim of the cup
6. Record the starting time: __________
7. Place your cup in the designated area where it won’t be disturbed

Initial Observations:

Describe the appearance of your celery stalk:

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Day 2 – Observations (10 minutes)

Time elapsed: ________ hours

1. Observe your celery without removing it from the water
2. Look for any color changes in the leaves or stalk
3. Record your observations below

Day 3 – Final Observations & Dissection (30 minutes)

Time elapsed: ________ hours

1. Remove the celery from the water
2. Observe the leaves and stalk carefully
3. Your teacher will help cut cross-sections of the stalk at different heights
4. Examine the cross-sections to see where the colored water traveled

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Data Collection

Observations Table:

Time	What I observe in the leaves	What I observe in the stalk
Day 1 (Start)
Day 2
Day 3

Cross-Section Drawings:

Draw what you see when looking at the cut end of the celery. Color the parts where you see the food coloring.

Bottom of stalk:

Middle of stalk:

Top of stalk (near leaves):

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Analysis Questions

1. How long did it take before you could see color in the leaves?
2. Describe the pattern of coloring you saw in the cross-section. Was the entire celery stalk colored, or just certain parts?
3. What plant tissue does the colored part represent?
4. Why did we cut the bottom of the celery at an angle before starting the experiment?
5. What would happen if you covered the leaves with a plastic bag? Explain your reasoning.
6. In a real plant growing in soil, what does the celery stalk represent? What do the leaves represent? What does the colored water represent?
7. Why is transpiration important for plants?

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Conclusion

Write a paragraph (4-5 sentences) explaining how water moves through plants and what you learned from this experiment.

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Extension Challenge (Optional)

Design Your Own Experiment:

What variable could you test to see how it affects water transport in celery? (Examples: temperature of water, cutting leaves off, using different colored water in split stalks)

My variable: _____________________________________________________________

My hypothesis: ___________________________________________________________

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Teacher Notes:

• Set up on Monday, observe Tuesday, dissect Wednesday
• Use fresh celery with leaves still attached
• Food coloring shows up best in 24-48 hours
• Red or blue food coloring works better than yellow/green
• Can split a stalk lengthwise and put each half in different colors for a “rainbow” effect
• Save one stalk for demonstration when cutting cross-section

Seed Germination Lab

Testing Variables That Affect Seed Growth

Name: _____________________________ Date: __________ Period: ____

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Purpose

To investigate how different environmental factors (light, water, and temperature) affect seed germination and early plant growth.

Background Information

Germination is the process by which a seed begins to grow into a new plant. For germination to occur, seeds need certain conditions. Inside every seed is:

• An embryo (baby plant)
• Cotyledons (stored food for the embryo)
• A seed coat (protective covering)

Seeds remain dormant (inactive) until the right conditions trigger germination. In this experiment, you’ll test how different variables affect whether seeds germinate and how well they grow.

The three main factors we’ll test are:

• Water – needed to activate enzymesProteins that speed up chemical reactions in the body. and soften the seed coat
• Light – some seeds need light to germinate, others don’t
• Temperature – affects the speed of chemical reactions in the seed

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Question

How do water, light, and temperature affect bean seed germination?

Hypothesis

Write your prediction for each variable:

Water: I predict that seeds with _________________ water will germinate _________________

because _________________________________________________________________

Light: I predict that seeds in _________________ will germinate _________________

because _________________________________________________________________

Temperature: I predict that seeds in _________________ temperatures will germinate _________________

because _________________________________________________________________

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Materials (per group)

• 12 bean seeds (lima beans or pinto beans work well)
• 4 small plastic cups or bags
• Paper towels
• Water
• Labels or markers
• Ruler
• Access to different locations (light/dark, warm/cool)

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Safety Rules

⚠️ READ BEFORE STARTING:

• Do not eat the seeds
• Wash your hands after handling seeds and wet paper towels
• Wipe up water spills immediately
• Report any mold growth to your teacher

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Procedure

Setup (Day 1):

You will set up 4 different experimental conditions. Each setup will have 3 seeds.

Setup 1: CONTROL (Ideal Conditions)

1. Fold a paper towel and dampen it with water (moist but not dripping)
2. Place 3 seeds on the paper towel
3. Put it in a plastic cup or bag
4. Label: “Control – Water, Light, Room Temp”
5. Place in a well-lit area at room temperature

Setup 2: Testing WATER (No Water)

1. Use a DRY paper towel
2. Place 3 seeds on the dry paper towel
3. Put it in a plastic cup or bag
4. Label: “No Water – Light, Room Temp”
5. Place next to the control

Setup 3: Testing LIGHT (No Light)

1. Fold a paper towel and dampen it with water
2. Place 3 seeds on the paper towel
3. Put it in a plastic cup or bag
4. Label: “No Light – Water, Room Temp”
5. Place in a dark location (cabinet, drawer, or cover with box)

Setup 4: Testing TEMPERATURE (Cold)

1. Fold a paper towel and dampen it with water
2. Place 3 seeds on the paper towel
3. Put it in a plastic cup or bag
4. Label: “Cold – Water, Light”
5. Place in refrigerator (if available) or coolest location possible

Important: Check your seeds every day for the next 7-10 days!

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Data Collection

Observations Table:

Check and record observations every day or every other day. Measure root length in millimeters (mm).

Day	Control	No Water	No Light	Cold Temperature
1
2
3
4
5
6
7

What to record:

• Number of seeds germinated (showing roots)
• Length of longest root
• Any leaves appearing
• Color changes
• Other observations

Final Results (Day 7):

Setup	# of Seeds Germinated (out of 3)	Average Root Length	Other Observations
Control
No Water
No Light
Cold

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Analysis Questions

1. Which setup had the best germination rate (most seeds sprouted)? Why do you think this happened?
2. Did the seeds without water germinate? Explain why or why not.
3. Did the seeds in the dark germinate? What does this tell you about whether bean seeds need light to germinate?
4. How did temperature affect germination? Was it faster or slower in the cold?
5. If seeds in the dark germinated, where did they get energy to grow if they couldn’t do photosynthesis?
6. Were your hypotheses correct? Explain what surprised you or what you predicted accurately.
7. Why is it important that we used 3 seeds for each condition instead of just 1?
8. Based on your results, what advice would you give a farmer about the best conditions to plant bean seeds?

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Graphing Your Results

Create a bar graph showing the average root length for each experimental setup on Day 7.

(Draw your graph below with labeled axes)

X-axis label: _______________________

Y-axis label: _______________________

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Conclusion

Write a paragraph (5-6 sentences) that:

• States which variables are necessary for bean seed germination
• Explains what happened in each experimental condition
• Discusses whether your hypotheses were supported
• Connects to what seeds need in nature to grow

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Real-World Connection

Think about it: Why do you think seeds can survive in the ground for months or even years without germinating, but then suddenly sprout when conditions are right?

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Teacher Notes:

• Lima beans or pinto beans from grocery store work great (cheap!)
• Setup takes 20-30 minutes; observations take 5-10 min every 1-2 days
• Best to run for 7-10 days total
• Refrigerator for cold condition works well, or use ice packs
• Dark condition can be a closed cabinet or box
• Seeds usually germinate in 3-5 days under good conditions
• Watch for mold if too wet – have students re-dampen paper towels as needed
• Can extend by having students transplant sprouted seeds into soil

Xylem & Phloem Microscopy Lab

Identifying Vascular Tissues in Plants

Name: _____________________________ Date: __________ Period: ____

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Purpose

To observe and identify xylem and phloem tissues in plant stems using microscope images, and to connect these structures to their functions in water and nutrient transport.

Background Information

In the celery lab, you saw colored water travel up through the celery stalk. But what exactly was carrying that water? Plants have a specialized transport system called vascular tissue made up of two types of tubes:

XYLEM:

• Transports WATER and MINERALS from roots UP to leaves
• Made of dead, hollow cells stacked like straws
• Has thick, strong walls (often lignified)
• The “plumbing” that carried the colored water in your celery!
• Flow is ONE-WAY: roots → leaves

PHLOEM:

• Transports FOOD (sugars) made during photosynthesis
• Made of living cells arranged end-to-end
• Has thinner walls than xylem
• Can flow in BOTH directions (up and down)
• Moves sugar from leaves to other parts of the plant

In the celery lab, you saw the xylem work! Today you’ll look at microscope images to see what these tissues actually look like at the cellular level.

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Materials

• Microscope images (provided by teacher or online)
• Colored pencils (red and blue)
• Ruler
• This handout

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Procedure

Part 1: Reviewing Your Celery Lab Results

1. Think back to your celery experiment. Sketch the cross-section pattern you saw when the celery was cut: (Draw the circular outline of the celery stalk and show where the colored dots appeared)
2. Those colored dots were the xylem vessels that carried the dyed water up through the celery!

Part 2: Examining Microscope Images

Your teacher will provide you with microscope images of plant stem cross-sections. You will examine images showing:

• Overall stem structure
• Close-up of vascular bundles
• Individual xylem and phloem cells

For each image, carefully observe and complete the sections below.

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Data Collection & Observations

IMAGE 1: Plant Stem Cross-Section (Low Magnification)

What you’re looking at: The entire cross-section of a stem, showing multiple vascular bundles arranged in a pattern.

Sketch what you see:

Questions:

1. How many vascular bundles can you count? __________
2. What pattern do you notice in how they’re arranged? (circle, scattered, ring, etc.)
3. Can you identify the outer layer of the stem (epidermisThe outermost layer of the skin, made of stratified squamous epithelium.)? Mark it on your drawing.

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IMAGE 2: Single Vascular Bundle (Medium Magnification)

What you’re looking at: One vascular bundle showing both xylem and phloem tissues.

Sketch and label the vascular bundle:

(Use BLUE colored pencil for xylem and RED colored pencil for phloem)

Identification Guide:

• Xylem is usually on the INSIDE (toward the center of the stem)
• Xylem cells look larger, more hollow, with thick walls
• Phloem is usually on the OUTSIDE (toward the edge of the stem)
• Phloem cells look smaller, more densely packed

Questions:

1. Which tissue (xylem or phloem) has larger, more hollow-looking cells?
2. Why do you think xylem cells need thick walls?

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IMAGE 3: Xylem Cells (High Magnification)

What you’re looking at: Close-up view of xylem vessels.

Sketch what you see:

Observations:

Shape of xylem cells: ___________________________________________________

Thickness of cell walls: ________________________________________________

Do these cells appear to be alive or dead? ______________________________

Special features you notice: ____________________________________________

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IMAGE 4: Phloem Cells (High Magnification)

What you’re looking at: Close-up view of phloem tissue.

Sketch what you see:

Observations:

Shape of phloem cells: __________________________________________________

Thickness of cell walls: ________________________________________________

How do phloem cells compare to xylem cells in size? _____________________

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Comparison Table

Fill in the table below to summarize the differences between xylem and phloem:

Feature	Xylem	Phloem
What it transports
Direction of flow
Cell wall thickness
Cell size
Living or dead cells?
Location in bundle (inner/outer)

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Analysis Questions

1. Connection to Celery Lab: In your celery experiment, why did the colored water only show up in certain spots (the xylem) and not throughout the entire celery stalk?
2. Why do you think xylem cells are dead while phloem cells are alive?
3. If you could do the celery lab again with a substance that would color the phloem instead of xylem, where would you need to apply it and why? (Hint: Think about what phloem transports and where it comes from!)
4. Xylem cells have very thick walls made of lignin (the same stuff that makes wood hard). Why is this important for their function?
5. How does the structure of xylem cells (hollow tubes with thick walls) relate to their function of transporting water?
6. Trees can be hundreds of feet tall. How do you think water gets all the way from the roots to the top leaves? (Hint: Remember transpiration from the celery lab!)
7. Some plants have vascular bundles scattered throughout the stem, while others have them arranged in a ring. Why might different arrangements be beneficial for different types of plants?

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Real-World Application

Girdling: When a tree is “girdled” (bark is removed all the way around the trunk), the tree often dies even though the xylem is still intact inside.

Question: Based on what you learned about xylem and phloem location, explain why removing the bark kills the tree. What tissue is being cut off, and what process is disrupted?

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Conclusion

Write a paragraph (5-6 sentences) that:

• Explains the difference between xylem and phloem
• Describes how their structures relate to their functions
• Connects this microscopic view to what you observed in the celery lab

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Vocabulary Review

Match the term with its definition:

_____ Vascular tissue A. Sugar transport tissue with living cells

_____ Xylem B. System of tubes that transport materials in plants

_____ Phloem C. Water transport tissue with dead, hollow cells

_____ Transpiration D. Loss of water vapor from leaves

_____ Vascular bundle E. A group of xylem and phloem tissues together

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Teacher Notes:

Free Image Sources:

1. Berkshire Community College Bioscience Image Library – search “stem cross section”
2. Science Photo Library (some free educational images)
3. Wikimedia Commons – search: “plant stem cross section A cut or slice of the body or an organ for study. microscope,” “xylem cells,” “phloem cells”
4. MicroscopyU (Nikon) – has free educational microscopy images

Recommended searches:

• “Zea mays stem cross section” (corn – great vascular bundles)
• “Helianthus stem cross section” (sunflower – clear xylem/phloem)
• “dicot stem cross section”
• “vascular bundle microscope”

Lab Setup:

• Can project images for whole class OR print copies for groups
• Works great as follow-up 1-2 days after celery lab
• Takes 40-50 minutes
• Can use actual microscopes if available (celery cross-sections work great!)
• Consider showing YouTube video of xylem/phloem animation as introduction

Key Teaching Points:

• Connect back to the colored dots they saw in celery = xylem
• Xylem = water UP (think: X marks the spot for water eXtraction from roots)
• Phloem = food/sugar (Phloem and Food both start with ‘F’)
• Structure fits function (hollow tubes for transport)