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					                               APES Irradiated Seed Lab

Background: Ionizing radiation is an energetic form of radiation that can cause cell
mutations in living tissues. In animals radiation can cause burns, birth defects and
cancers. Cancers and birth defects are caused when the radiation passes through DNA
molecules causing the nucleotides to lose electrons. This leads to genetic mutations and
eventually cancer. Animal tissue is not the only type of tissue that is affected by
radiation. Plant tissues also contain DNA that can be destroyed. In seeds the radiation can
cause a variety of different mutations, which can lead to problems with the plant. When
we are dealing with radiation we often neglect the effect that a radiation leak would have
on plants and mainly focus on the problems that humans will have. No plants means no
food, so it is a major concern. In this lab we will determine exactly what the effects of
radiation exposure are on plants.

Purpose: To determine the effect of radiation on living tissues

Materials:     4 petri dishes
               1 magnifying glass
               4 developing domes
               4 blank labels
               4 foam discs
               mung beans, control
               mung beans, 50,000 rads
               mung beans, 100,000 rads
               mung beans, 150,000 rads

Procedure:
1. Place one of the soaked foam germination pads in the petri dish.
2. The seed packages are labeled with the radiation dose that the seeds received. One seed
package is labeled control. The seeds in the control package are normal and they were not
exposed to radiation.
3. Raise the cover of the germination chamber and place six seeds on the foam pad. Add
a few drops of water directly on the seed to hasten germination. Replace the cover to
reduce moisture loss and to keep out unwanted materials. Label the chamber with your
name, the date, and the radiation dose.
4. Repeat step #3 for each of the other packages.
5. Place the germination chamber in a lighted area where the temperature is between 60-
80 degrees F. Avoid direct sunlight, which may heat seeds enough to prevent
germination. Add one-half teaspoonful of water to the chamber every second day to
replace water lost or used.
6. Look at the seedlings every day. Use a magnifier to aid in seeing the root hairs.
7. When plants need room for upward growth, replace the cover with a development
dome. Continue to add 0ne-half teaspoonful of water to the chamber every second day.
8. When the plants outgrow the development chamber they can easily be transplanted.
Completely cover the foam pad with water and allow the roots to soak overnight, using a
spatula carefully scoop out the growing plants and place them in soil. Avoid damage to
the root structure. Cover plants with soil, place in moderate light, watering when
necessary.

Hypothesis: What do you think the differences between the control and the irradiated
seeds will be?

Data: Make an observation for each of the following parameters on a daily basis:
      1. Size of stem, leaves, roots
      2. Color of stem and leaves
      3. Number and pattern of secondary roots
      4. Relative number of root hairs

Analysis:
In paragraph form summarize the data. Explain why the data turned out the way it did.
Was your hypothesis correct? Were there any errors or problems with the lab that could
affect the data?

Conclusion

				
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posted:6/22/2011
language:English
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