Corn and Bean Seed Dissection
In the picture above the portion labeled embryo on the right is also known as the germ.
PreLab – Dissection means to take apart. We will be taking apart the corn and the bean seed to learn
about what they contain. The seed we will dissect has been soaking to allow us to open the kernel.
You can find more information about seeds on page 87 and page 90 in the Holt textbook. To do this
lab you will have to understand how to estimate percentage. The table below may be helpful.
10% is 1/10
50% is ½
80% is 4/5 or 8/10
25% is ¼
66% is 2/3
100% is the whole thing.
33% is 1/3
75% is 3/4
Corn and Bean Seed Dissection Lab
We will be looking at what makes up corn and bean seeds. Label the picture above
with the words corn seed and bean seed.
a.
From the picture above, what are the three things found in a seed?
_______________ ______________________________________________________
Corn seed dissection. A corn seed is often called a kernel.
1. Put a corn kernel on the paper plate and label different areas on the place to
correspond to the four areas of the kernel (1. Tip cap 2. Pericarp (hull or seed
coat) 3. Germ or baby plant, also called embryo and 4. Endosperm divided
into floury part which is white and horny part which is yellow).
Corn and Bean Seed Dissection
2. Remove the tip cap of the kernel and place it on the section of the plate you have
labeled Tip Cap.
3. Remove as much of the layers of hull called pericarp as you can and place it on
the part of the plate you have labeled Pericarp.
4. Locate the embryo or Germ. Place it on the section of the plate you have
labeled Germ.
5. What remains is the endosperm. The endosperm has two parts; floury
endosperm (white part) and horny endosperm (yellow part).
Estimate the percentages that each part of the kernel represents and complete
the chart.
Part
Pericarp
Germ
Endosperm
Tip Cap
Info
The outer covering
protects the kernel and
keeps in the nutrients. It
resists water and water
vapor and is does not
provide a good habitat for
insects or microbes.
The germ is the only
living part of corn kernel.
The germ contains the
DNA, enzymes, vitamins,
and mineral needed for
the seed to grow.
The endosperm is the
majority of the dry weight
and is the source of
energy (starch) and
protein for the seed when
it starts to grow. Starch
is the part of the plant
most used by industry for
fuel, sweeteners
bioplastics and other
products.
The tip cap is where the
corn attaches to the cob.
It is through here that the
water and nutrients flow
into the kernel.
Your Estimate of %
Corn and Bean Seed Dissection
Draw a picture of a corn seed.
Put three labels on your drawing.
This is the end of the corn dissection. You will need to have a bean that has been
soaked in water to start the bean dissection.
1.
2.
Draw a picture of the outside of your bean.
Describe what it looks like in words.
____________________ __________________________________________________
_ _____________________________________________________________________
3.
4.
What is the white outer covering on the bean called? ________________________
Try and take off the white seed coat. Why do you think it’s so hard? ___________
________________________________________________ ______________________
5. Draw a picture of what your lima
bean looks like on the inside.
the stored food, the embryo,
cotyledon and seed coat.
Label
Corn and Bean Seed Dissection
Questions. You may have to use your textbook to help you find the answers.
1.
What is the purpose of the stored food inside the seed?
___ _____________________________________________________________________
__ _______________________________________________________________________
2.
What is a cotyledon?
_ _ _____________________________________________________________________
__ _______________________________________________________________________
3.
What does pollination mean?
__ _____________________________________________________________________
__ _______________________________________________________________________
4. What does the book say are 4 traits of plant? (pp. 78-79)?
___ ____________________________________________________________________
__ ______________________________________________________________________
Below is a more detailed picture of the seeds. If you finish early, read 166-167 to prepare
for tomorrow’s activities.