Soil Seed Bank Lab

Due Date_________ Score_________


 Flowering plants (Angiosperms) reproduce using seeds.  Most plants produce many seeds.  Seeds cannot move them selves thus depend on various types of fruit to help move them.  Draw and describe 5 different ways that fruits help disperse seeds [teacher- include one way us humans disperse noxious weeds as an example]:

1.                                                      2.

3.                                                      4.


 Once a seed lands on the soil, it usually stays on or in the soil at that spot.  However, not all seeds sprout the next spring (year).  This allows plant seeds to sprout over a number of years thus increasing a plant species chances of surviving bad years.  For instance, though most sprout in the first few years after they fall onto the soil, some spotted knapweed seeds last 10 years in the soil before they sprout.  These unsprouted seeds in the soil are called the soil seed bank.

 1. Take a half gallon paper (waxed) milk carton and cut it off about 6 inches high. Punch 2-3 small holes in the bottom and wash it out.  Label it with your name and the date with a permanent marker.
 2. As a class, discuss what different habitats in your area you would like to take soil samples from.  Make a list of every student and the habitat they will sample.  Attach the list to this lab.
 3. Go to the habitat you have agreed upon in class and lightly pack about 5 inches of top soil from this habitat into your carton (your soil sample).  Be sure you have permission to take top soil if it is not your property (and from your parents if it is...).
 4. Bring the filled carton into the classroom and place it in a warm, well lighted area.  Water it lightly.  Keep the soil moist but not soggy.
 5. Take data on a schedule provided by your teacher.  Use your own paper.  For each observation:
a. note the date
b. list the number of plants that have sprouted
c. sketch each plant
d. use the sources provided by your teacher and any other sources you can find to identify each plant if you can.

Results: Sum what happened in the lab.

Discussion Questions: Answer these on your own paper in complete sentences.
1. What is the soil seed bank and why is it important for the survival of a plant species?
2. What are annual, biannual, and perennial plants?
3. Draw and label the life cycle of a flowering plant [see your text, remember that a cycle is a circle].
 4. Spotted knapweed is a category 1 noxious weed in the State of Montana.  That means that if you have it on your land, you need to control it.  One way to do this on small infestations is to hand pull all the plants each year (wear gloves!) before they flower and go to seed.  For how many years would you have to check your land and pull the weeds?  Why?
5. Using the resources provided and the Internet, list and briefly describe 4 other ways to fight (control) spotted knapweed.
6. Define monocot and dicot.  Draw a sprouting monocot and dicot from your seed bank data.
7. Make a chart that contrasts monocots and dicots.  Which type are most noxious weeds?

Conclusion: A minimum of 3 sentences of summary of the lab and 3 sentences of your opinion of the lab.


Teachers: feel free to copy and paste this into your favorite word processing program and modify it to fit your needs.  

Materials: Information on fruits and flowers (most biology and life science texts will have this) and plant identification, examples of fruits with different dispersal strategies, permanent marker, half gallon milk jugs or other suitable containers (you may want to have the students bring these), a place for these plants to grow with a warm lighted environment (grow lights or natural light), a water source, drainage, and hand lenses.
Introduction: Introduce flowering plants, types of flowers, and idea that a flower produces a fruit with seeds in it.  The function of the fruit is to disperse the seeds.  Use some of the classic weed examples of a houndstongue seed (fruit) sticking to your clothing or a spotted knapweed seed head (fruit) being shut into the door of a car and the seeds being driven to a new area and dispersed when the car door is opened.
The soil: A suggestion would be to make your own container and fill it with top soil from a waste area of the school grounds as an example for the students.  This will demonstrate how to set up the container.  Stress that the soil must come from the top 10 cm of the ground so it will have the most seeds.  Try and encourage the students to get soil from many habitat types in your area.  This will produce a nice diversity of plants that will sprout.  Make sure they clearly mark their pots and punch holes in the bottom for water drainage.  Be sure the place you choose to put these pots can handle the excess water drainage.
Data: Plant sprout ID is tough 'though it is usually easy to tell the difference between grasses (monocots) and broad leafed plants (dicots).  The main goal of the lab is to demonstrate the existence of the soil seed bank and its importance in noxious weed survival/dispersal.  Some options would be: 1) just have the students count the number of sprouts, 2) have the students count the number of monocots and dicots, or 3) you can get into plant ID as deeply as you want.  Students should take data for one or two months.
Clean up and disposal: If you suspect that noxious weed seeds might occur in any of the soil samples, double bag them and see that they go directly into a land fill.  PREVENT THE SPREAD OF NOXIOUS WEEDS!!  Other wise, they can be thrown into the school dumpster or put back where the soil came from.

Goals: Feel free to copy and paste these into your lesson plans and modify as you see fit.
(-) = "The students will..."
-understand and explain the existence of the soil seed bank and its importance in noxious weed survival/dispersal.
-draw and describe the functions of seeds, flowers and fruits.
-sprout plants and record data on these.
-draw and describe the life cycle of a plant.
-describe various plant growth histories.
-list ways to control noxious weeds.
-compare and contrast monocots and dicots. HOME    Back to Teacher Curriculum