Teacher's Section: Seed Germination

Lessons1-5

Germinating Seeds- Let’s Observe!

Lesson 1 A _ ?

Day 1

Lesson Intention: This lesson is designed to teach students some germination techniques that they will use in a future experiment. These germinating seeds will provide a springboard for questions in the next few lessons. This is a simple lab intended to give students an opportunity to observe seed germination day to day, while taking narrative observation notes.

BY THE END OF THIS LESSON STUDENTS WILL BE ABLE TO:

germinate bean seeds on their own
observe daily change in seed germination and plant growth
write and draw detailed observations of changes and differences in types of seeds

Teacher Preparation:

NOTE: It’s best to do this on a Friday so the seeds can germinate over the weekend.

Have the necessary quantity of beakers, trays, paper towels, newspapers, plastic wrap, and water ready and available to students
Make sure there is a variety and quantity of beans and seeds available such as lima, kidney, white and/or black beans, pumpkin and/or squash seeds, and peas. (You might want to try to collect some native seeds such as mesquite, palo verde or native squash through Native Seed Search.)

Materials per student: In class journal, pencil

Materials per team: 1 beaker or tray, 8-10 seeds of a few varieties, water, 2 paper towels, wad of newspaper

Bellwork: What will happen to dry, hard beans when they are put in a plastic bag with a moist paper towel? How do you know?

Step by Step Lab

After giving the students 2-3 minutes, call on different students to answer the bellwork question. Students can draw what they think will happen on the board if the would like.
Tell students that today they will do something like the bellwork question and see what happens in a few days.
Demonstrate to students the 2 methods they will choose from then allow them to do it on their own after you have given all instructions:

Wet 2 paper towels then line the walls of a large beaker with the towels. They should stick to the glass.
Fill the core of the beaker with a crumpled sheet of newspaper. The newspaper will hold the wet towels in place.
Pour water into the bottom of the glass until it is about 2-3 cm. deep.
Now "plant" the seeds between the glass wall of the beaker and the wet paper towels. Place several different kinds of seeds, turned in different directions.
Use a glass-marking pen to number your seeds.
Record this information in your journals.

Cover the bottoms of a large tray with 2 or 3 layers of paper towels or a combination of towels and newspapers.
Dampen the paper towels but DON"T soak!
Place seeds in separate regions of the try.
Cover the try with plastic wrap
Apply stick-on labels so you will be able to identify which seeds are which.
Draw your set-up in your journal

After students have seen a demonstration of what they should do, have them gather their materials in an orderly manner after they have agreed on the method of germination.

5. Students should follow procedures then take notes in their journals of what they’ve done by describing the seeds used, where and how they were placed in the tray or beaker.

When all teams have completed their set-up, make sure the teacher goes from group to group to check on set-up and how set-up was recorded in journals.

Explain to students that they will start each day by taking detailed, written observations of their seeds. They may use measuring devices if they choose such as rulers or graduated cylinders. Tell them it is important to maintain the moisture in their beakers and they can maintain their seeds as long as they like.

Splitting A Seed: Form and Function

Lesson 2 AÀ

Day 2

Lesson Intention: This lesson is designed so students get an opportunity to take a close look at seeds- both in the dry, hard state and in the imbibed state, using eye loupes or magnifying lens. Students will open imbibed seeds to get a look at the embryos: their food source, protective coating, and first leaves. Students will notice some parts on their own. Other parts will be pointed out. Students will make drawings of their opened embryos, labeling them with correct terminology. Students will guess the function of parts, then be given the correct function.

BY THE END OF THIS LESSON STUDENTS WILL BE ABLE TO:

dissect an imbibed seed carefully
observe and detect small seed parts
draw and label the parts of a seed
explain the function of each part of the seed embryo

Teacher preparation:

Imbibe seeds by soaking a variety of kidney, lima, northern beans, and corn seeds in a bowl or glass for 24 hours.

Put a variety of imbibed seeds into each team’s baggie. Make sure each team has at least 8 lima or kidney beans as these are easily dissected and seen.

Have ready: labeled seed parts overheads, eye loupe, pointer, seeds, bellwork on board or overhead

Materials per student: in-class journal, pencil; eye loupe or magnifying lens, a pair of tweezers or forceps, sharp knife or dissecting scalpel, paper towel, ruler.

Materials per team of four: a small Ziplock® bag of a variety of dry seeds/beans, a small Ziplock® of prepared imbibed seeds: lima beans, kidney beans, corn.

«Bellwork: Answer these questions: Where do you find seeds in the plant? What shape are they? What is the purpose of seeds? How big are seeds? What is inside of a seed?

Step by Step Teacher lead lab/ discussion:

1. Open the class by calling on students to read some of their bellwork answers. The idea is to find out what students know within the first 10 minutes of class. Students should start to see that many of the questions have an infinite number of answers. Leave the last question for last. Students may be stumped. This is a good time to explain to the students what they will be doing with seeds in today’s lab. If questions come up at this time have a student record them on a large sheet of paper, the board, or in a notebook., but hold off on answering them.

Give instructions for picking up/ handing out materials.

Have students take some red kidney beans, lima beans, and corn out of the dry-bean bag. Using eye-loupes students should observe the beans closely. Ask them what details they see using descriptive language. Write these descriptions on board or overhead. They can write these descriptions in their journals, and also make drawings. Ask students to talk about then answer this questions in their teams: Why do seeds dry up, stay in their seed shape and not fall apart?

After giving students a few minutes, discuss answers as a class.

Now ask students to take imbibed seeds out of bag. Using eye loupes, students should observe and write down differences between the dry and wet seeds and new details they notice about the imbibed seed. Instruct students not to open seeds yet. (You may notice students pointing out things to each other. Encourage this.)

Begin dissection. Have students carefully remove the softened seed coat from an imbibed lima or kidney bean(NOT corn). Talk about the color, texture and function of the seed coat. Have students begin a drawing a label it with TESTA. Point out the form and function of the MICROPYLE and HILIUM. Show overhead. Have students draw and label parts in their journal. (Students should have the labeled drawing on one sheet of their journal while using a facing sheet to keep track of the function of the part.)

Have students slide their fingernails into the seam on the convex(rounded) side of the seam and separate the two large COTYLEDONS. Students should be able to see the tiny plant embryo and its parts- the EPICOTYL, HYPOCOTYL, PLUMULE, and RADICLE. Using eye loupes students should observe these, draw and label. Ask students what they think the function of each part is or what the part will become in the adult plant. Discuss and give correct information. Have them lay their dissected seed aside.

Now have students take imbibed corn seeds from bag. Using the forceps or tweezers have students peel the TESTA from the seed. Have them look at the flat, wide side of the seed. Have them describe aloud the structures they see. Can they match any of the structures of the previous seeds to those of the corn seed? What so they notice about the number of cotyledon in corn? Here you can introduce the words DICOT and MONOCOT. Where do they recognize the root word COT from?(cotyledon) Show the overhead section 2b. Point out the ENDOSPERM and its function. Explain its function. Why doesn’t the lima bean have an endosperm?

Instruct the students to use the scalpel or sharp knife to cut the corn seed in half along the dotted line on overhead section 2b. If they turn the seed 90° they should be able to see the structures in overhead section 2c. Have them draw and label their dissected corn seed.

Direct students in cleaning up materials.

After students return to their seats, have students close their journals. Calling on individuals ask review questions such as:

What did you learn about the differences between lima and corn seeds?
What is the function of the testa?
What is the shape and function of the cotyledons in a lima beans?
Why does a corn seed have an endosperm and a lima bean not?
What will become the plant’s first true leaves?
What does the radicle become?
Why does the lima bean have a micropyle?

12. After checking for understanding, clear up any misconceptions or misunderstandings given time, or follow up the next day.

Beans(dicots) are chosen for this dissection lab because they imbibe (absorb water) and germinate readily. Monocots like rice, corn, and other grains take longer to absorb water. The corn seeds should be soaked several days prior to the beans.

When students are observing their dry beans they should notice the HILIUM and MICROPYLE.

HILIUM- a small scar where the seed was attached to the parent plant
MICROPYLE- a small pore or hole near the hilium through which the pollen tube grew before the egg within the ovule was fertilized.

When students observe their soaked beans they should notice:

the TESTA- The seed coating which protects the plant embryo and reduces the evaporation of water from the plant;
the COTYLEDONS- the first seed leaves that serve as food storage organs for the embryo. They are attached just below the embryo shoot or PLUMULES- leafy structures that will become the plants first true leaves;
the EPICOTYL- contains the PLUMULES at the upper end. The lower end will become part of the stem;
the HYPOCOTYL- the tougher, thicker part of the embryo. The lower end (the RADICLE) will become the root. The upper end will become part of the stem along with the lower end of the epicotyl.

After students cut open the corn seed and compare differences with the bean seed you can explain the following:

In DICOTS, the cotyledons have absorbed the stored food from the endosperm, therefore an endosperm cannot be found.
In MONOCOTS like corn, the food storage takes place in the ENDOSPERM..

Seed Germination and Variables

Lesson 3 A ? À

Days 3,4 & 5...?

Lesson Intention: This lesson is designed as in inquiry lab to give students a chance to come up with some questions about what affects the germination of seeds. We will pool questions as a class and refine questions so they are testable. Then in teams, students will design an experiment which answers a specific question. Students will identify the variables and design a control to test the variables. They will provide results on a V-map which will be presented to the class. By now, seeds from Lesson 1 will be in various stages of germination.

BY THE END OF THIS LESSON STUDENTS WILL BE ABLE TO:

recognize a testable question about seed germination;
design an experiment that answers a question about seed germination;
use measurements and diagrams to show change over time;
graphically represent experimental design, data and conclusion in a v-map;

Teacher Preparation:

Have Lesson 1 completed so students can refer to it.
Make sure there is a variety and quantity of beans and seeds available such as lima, kidney, white and/or black beans, pumpkin and/or squash seeds, and peas. (You might want to try to collect some native seeds such as mesquite, palo verde or native squash through Native Seed Search.) [Same as used in Lesson 1]
Have a variety of growing mediums, measuring devices and containers on hand such as sand, soil, gravel, trays, beakers, egg cartons, plastic soda bottles, yoghurt containers, newspapers, paper towels, plastic wrap, baggies, thermometers, refrigerator and freezer, growing racks with grow lamps, window area, heating devices, triple balance beams, graduated cylinders, etc.
Each team should have a copy of Team Behavior Scoring Rubric, and a V-Map Scoring Rubric, and Experimental Design Checklist in a team folder. Also, make an overhead of each to help in review of what is expected.
Bellwork should be on board or overhead. Have a piece of butcher paper (per class) hanging on the wall or board.

Materials per student: in class journal, pencil/pen

Materials per team: any materials needed from the above list, scoring rubrics and Experimental Design Checklist in team folder, germinating seeds from Lesson 1.

BELLWORK [Day 1]: Go pick up your seed germination beakers from 2 days ago. Take notes in your bellwork journal about what has happened to each of the seeds. Observe carefully without removing the seeds from their positions. In your group come up with 5 questions you have about why something did or did not occur, then come up with three "If we do this, THEN what will happen?" questions.

Step by Step Teacher lead lab/ discussion:

After giving the students 5-10 minutes to work on the bellwork, open the discussion by asking students to share their observations. Students who want to share drawings can go to the board and do so. What did they notice about the different seeds? What happened to seeds that were placed upside down? Which seeds germinated? Which are taking a longer time?
Take a moment after using the word GERMINATED to ask students what they think it means. Get several ideas. Come up with a definition based on the students’ feedback. Have students write this definition in their In-class journals.

Now ask teams for their questions one at a time. Ask the student from Team One to say one of the questions that team came up with. Then go to Team Two, then Team Three, etc. Go around the teams until there are no more questions. Have a student recorder (that writes well and quickly) go to the butcher paper to write the questions as they are presented. As teams state their questions, help them to reword or explain so their questions are explicit.

Questions may be:

Is water essential for germination? How much is too much or too little?
Is soil necessary for seed germination?
How does temperature affect germination?
If we used hot water, would the seeds germinate?
Is light or darkness essential for seeds to germinate?
If I put seeds in the dark, with water, will they germinate?
Do seeds need air to germinate?
Does the type of soil in which the seed is planted affect seed germination?
If I place seeds a refrigerator will they germinate? in a freezer?
Is the seed coat necessary for germination?
Can bean seeds (embryos) grow without their cotyledons?
Can another food source take the place of the cotyledons?
Does the depth at which seeds are planted have any affect on their germination?
Can a seed germinate in soil if it is placed upside down?
What percentage of the same type of seeds will germinate given the same conditions?

Give students their team assignment. Tell them that they will choose one question, reword it so it is a testable question, then design an experiment that will answer the question. Explain that the question must be approved by the teacher before the design of the experiment is begun. They will do this by all raising their hands after they have written the formal question. From their question they will provide a hypothesis and an experiment. Data tables and record-keeping devices must be in place before permission is granted to begin the experiment. Show scoring rubrics and Experimental Design Checklist on the overhead as students follow the ones provided.
[Day 2]Open with bellwork: Write down 3 things to remember while you and your group work today.

Have students quickly share their ideas. Share any last-minute reminders yourself. Students work in teams to design a testable question, hypothesis, data tables and experiment and only move on after each section has been approved. Move around from group to group to give feedback, ask questions, and share ideas.

[Day 3]Open with bellwork: Without talking to your group, write no less than a five-step plan of what you think you and your group need to accomplish today. When you finish, compare this list with your team mates.

As students rewrite and are approved, they may begin the set-up of their experiment.

When groups finish their set-up they should make their word list for the V-map. They should also make a group list of what they already know about germination in the form of statements.
[Day 4]All teams should have completed their set up and some of their V-map by the end of today.

Note to teacher: Checking on team experiments can be the bellwork for the next week or so. Assign two days one to two weeks later, when experiments are complete, for students to work on their V-maps and present their findings.

GERMINATION or seed sprouting takes place easily with seeds such as limas and kidney beans. If some native seeds are used such as mesquite, acacia seeds or other desert legumes, students should notice from Lesson 1, that these seeds have not swelled and changed like the beans. Some seeds require a period of DORMANCY before they germinate. Dormancy my be broken in many of the desert plants by scarification. Because these seeds have seed coats that are thick or tough for the purpose of preventing the absorption of water or oxygen, these seeds need to be artificially nicked, scraped , or cracked. This can be done with a knife, be freezing and thawing several times, or by dipping in concentrated acid for a few minutes.

Students may have questions about how this benefits the plants to have a period of dormancy. For many plants dormancy is an adaptation for survival. This could become a class discussion in itself or it could become a research project! The topic of dormancy is your choice to tackle. If you have a class or team that seems to be moving ahead of the rest, or it fits into a "teachable moment" then go for it! You may want to steer teams away from tackling an experiment dealing with dormancy. They may get frustrated at the length of time it takes for their seeds to germinate. Depending on the background knowledge and experience of your students, guide their questions and hypotheses.

The best time to find seeds in Tucson is during the mid-late summer months of July and August. Mesquite, acacia, palo verde, ironwood are readily availabe by taking a short walk in the Tucson Mountain Park or along the Rillito River Path. Flower and cactus seeds are also available then.

Native Seed Search, a local and national Native American seed collection organization sell such seeds and their products. (Presently on 4th Ave.)

National Geographic Laser Disk- "Plants"

Lesson 4

Day 6

Lesson Intention: Using the laser disk is an opportunity for students to see visual representations of concepts we have been talking about. This laser disk shows some time-lapsed photography of seed germination so students get a better understanding of what occurs over several days. There are labeled diagrams and different types of seeds.

BY THE END OF THIS LESSON STUDENTS WILL BE ABLE TO:

describe the stages of growth that occur during seed germination
name the interior parts of the seed
visually represent a seed’s interior

Teacher Preparation

-Have laser disk player and laser disk set to beginning frame.

Materials per student: In class journals

(Bellwork should continue to be students observing their germinating seeds)

Step by Step:

1. Open the class by asking different students what they have observed in their germination beakers or trays. Anything new today? What amount of growth? What seeds aren’t germinating at all?

2. Begin the laser disk. Stop occasionally to discuss. Ask questions. Have students ask questions. ( I always let the students know that they may interrupt a movie or laser disk at anytime by raising their hand.)

3. Have students draw any diagrams from the laser disk you feel are useful or necessary.

Lesson 5

Due Date__________

Materials: grass seed from your teacher, 1 sponge, scissors, 2 saucers or foam trays(packaging) from meat or fruits, water, measuring cup, window or light source, dark area such as closet or box

Prediction: Will grass seeds germinate without light? Will seeds germinate at the same rate without light as with light? Will plants grow the same as in light and in the absence of light? What are some differences that might occur?

Procedure:

1. Cut the sponge in half.

2. Place each half on its own saucer or small tray.

3. Sprinkle grass seeds over each sponge.

4.Add ½ cup water to each saucer ( the water should be absorbed into the sponge).

5. Place one saucer with sponge and seeds by a window or constant light source.

6.Put the other saucer in a dark closet or box that can be sealed (such as a shoe box).

7. Design a data table that you can write your observations in each day. It should have a categories for time checked, day of experiment, added water, and observations.

8. Check your saucers each day for 2 weeks. If the saucer or sponge is getting dry you need to add water. Keep track of how much water you add to each saucer. (Which sponge do you think will need more water more frequently? Why?) Check your seeds daily and take detailed observation notes.

Write down your predictions and reasoning before you begin.

Results and Observations: After 2 weeks of observations, what did you discover? Draw diagrams, color pictures, rewrite your observations so they are clearly understood.

Hypothesis: Think about the reasons why you got the differences you did between the plants in light and those in dark. Come up with a hypothesis that explains the phenomena you saw.

Based on what you learned in class about chlorophyll, design an experiment to test your hypothesis. How would you prove that your thinking is correct?

Just write what your test would be. Don’t do it. Remember: Step by step procedures!

Conclusion: Do you think you did the experiment correctly? What mistakes did you make? Why was the grass kept in the dark different?( Explain it in terms of what you learned about the process of photosynthesis.) What kind of growth occurred in the light and in the dark? What accounts for these differences? What did you learn from running this experiment? What questions do you have after completing the experiment? What curiosities?

Put the 2 sponges with growing seeds in plastic baggies or wrapped in plastic wrap. Make sure your name is on them. Hand them in with your POW write up.

eline

Teacher's Section

Units:

Seed Germination

Photosynthesis and Respiration

Flowers: Form, Function and Sexual Reproduction
Bees and Bats as Pollinators

Coevolution of Plants and their Pollinators