What Turns Seeds On?

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Sample Procedure

1. Soak 30 seeds in 100 mL of each solution for 24 hours, i.e. GA₃, ABA, GA₃/ABA, distilled water (control).
2. Treat the seeds with Clorox for 1-2 minutes.  Click here for instructions to disinfect the seeds.
3. Cut the seeds in half with a sterile scalpel or razor blade.  Be sure to bisect the seeds.
4. Press the seeds onto the starch agar plate.  There should be 4 half seeds per plate with the cut side in contact with the agar.
5. Store the plates at room temperature for 24 hours while seed germination occurs.
6. Keep track of the time elapsed from when the seeds are placed on the agar until the Lugol's iodine solution is applied.  The seeds will be observed, and data will be collected at 24, 48, 72, 96 and 120 hours.
7. After the time elapses, spray the Lugol's iodine solution over the entire surface of the plate.  The Lugol's iodine solution will bind to all of the remaining starch making it unavailable to bind to any additional a-amylase produced.  If interested in observing the effects of plant hormones over a longer period of time, it will be necessary to start over with a new agar plate.
8. Measure the length and the width of each halo (including the seed) surrounding each of the seeds.  Each halo represents the starch which has been digested by a-amylase produced by the seed during germination.  Below is a picture of an agar plate with halos and treated with Lugol's iodine solution:

 
 
 
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