A mutation is just a change in the DNA of a plant or animal. The change can be good or bad. Sometimes a mutation occurs in the cells that form our skin, and we have a patch of skin that is a different color. We are going to do an experiment with a plant called arabidopsis. This is a small plant that forms tiny seeds. Scientists like this plant because it is easy to grow. We have two sets of seeds. One set is from a normal plant. The other is from a plant that has a mutation. The mutation inactivates a gene that codes for a protein that helps the plant get iron from the soil. Without this protein, the mutant plant grows slower and turns yellow because it has trouble getting iron from the soil. What do you think will happen if we give it water that contains lots of iron?
MATERIALS
Seeds from normal and mutant
plants
Potting soil
Plastic trays and pots
Grow light
Iron solution (0.5 grams
of Sequestrene in 1 L of water)
Saran wrap
Plastic cups or beakers
(two)
Eye-dropper
PROCEDURE
Put water in two cups. Label one normal and the other mutant. Put 6 seeds from a normal plant in one cup and 12 seeds from a mutant plant in the other. Put both cups in the refrigerator for 2 to 7 days.
Fill 3 pots with soil and place in a tray of water. Label one pot normal and two pots mutant. Use an eye dropper to distribute 6 seeds onto the surface of each pot. Gently squirt additional water to wet the surface of the pot. Cover the pot with plastic wrap and under the light.
When you see tiny plants remove the plastic wrap. Water as needed. (Let the surface just dry out before adding more water).
When the plants are a few days old, transfer one of the mutant pots to a tray containing the iron solution instead of water.
Watch
the plants grow and record your observations. The mutant plant that has
no iron supplement should begin to show differences after about two weeks
and these differences will get progressively more obvious as time goes
on.
Contributed by Erin Connolly