Adventures of the Agronauts Presents
Rosys International Space Station Experiment

 
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D. Rosy’s Seed Experiment on the International Space Station Materials and Directions

Classroom Kit Includes:

10 Phytagel filled Petri dishes wrapped with parafilm to maintain moisture
10 pieces of removable adhesive tac putty
  1 packet of radish seeds
  1 packet of alfalfa seeds
10 parafilm strips
10 cotton tipped swabs
10 blue graph sheets for measuring root/shoot growth
  1 magnifying glass

Directions:

  1. Pass out supplies. Each student or group will receive:

    1. 1 Petri dish

    2. 2 radish seeds (larger seeds)

    3. 2 alfalfa seeds (small kidney shaped seed)

    4. 1 cotton swab

    5. 1 strip of parafilm strip

    6. 1 small cup or tray of water

    7. 1 blue graph square for measuring root growth

    8. 1 graph square for drawing measurements (each student can receive their own)

 

  1. On the outside portion of the lid, write your group name or number on each Petri dish with a Sharpie marker.  Note: Labels should be small and out of the primary field of view. 

  2. With a sharpie marker add a straight line to the bottom (smaller) tray of the Petri dish, about an inch away from the edge, as shown in the diagram below.      

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  1. Remove parafilm from Petri dish.

  2. Open Petri dish. You may use a tissue to wipe off any excess condensation on the lid at this point. Do not touch the surface of the Phytagel with the tissue.

  3. Place Petri dish in front of you so that the line on the dish is horizontal to you. Please see diagram below.

  4. Wet cotton swab.  Shake off excess water.

  5. Take moistened cotton swab and press swab down onto one radish seed to pick it up.  The moist swab will hold the seed long enough for you to look at it and orientate the seed for proper placement.  

Example of radish seed orientation.
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Example of alfalfa seed orientation.
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Diagram of Petri dish, seed orientation and placement.

  
  1. Locate the hilum. The students will orientate one radish and one alfalfa seed with the hilum “up” and One radish and one alfalfa seed with the hilum “down”. Spacing should be equal distances along the line. Seed placement and orientation are demonstrated in the diagram above.  Please Note:  Seed orientation is not critical to this experiment, but should be done to the best of the student’s abilities.

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  1. All four seeds will be placed along the marked line.  Begin with the Radish seed, very gently place seed onto the Phytagel on the left side of line. The seed should NOT be pushed down into the Phytagel, but lightly placed onto the Phytagel with enough pressure that the seed sticks into the gel.

  2. Pick up the second radish seed with the cotton swab, place on the line, with the hilum orientated down. Again do not push seed into Phytagel, but place on top of the gel with enough pressure so that the seed sticks to the gel. 

  3. Next add the alfalfa seeds, the first orientated up from the line and the second down.  Note the alfalfa seed’s hilum is quite small, look for the line found in the middle of the kidney shape.     

  4. Close Petri dish and wrap the edges of the Petri dish with parafilm to keep Petri dish closed and to prevent drying of the Phytagel.  Please note:  The parafilm stretches and is long enough to stretch and wrap around the entire edge of the Petri dish.  Begin the stretching by placing the parafilm on the edge of the dish and hold with one finger.  Use your other hand to pull and wrap parafilm around the dish.  Once the parafilm is completely wrapped around the dish, press your fingers along the parafilm to ensure it is sealed to the dish.   

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  1. Let Petri dish lay flat for 24 hours.  This will help the roots grow into the gel rather than on top of it.

  2. After 24 hours, take measurements (See B. Suggested Experimental Timeline) and place a piece of removable adhesive putty tac on the flat surface of the bottom tray.  For best results, do not suspend the dish on a vertical wall. The dish is likely to fall.  Instead place the dish against a wall where it can also rest on table.  

Example of wall placement
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table

Optional Experiment:
After measurements have been taken on the fifth day, rotate Petri dish clockwise approximately 90 degrees in order to observe root gravitropism. Measure and discuss results.

 

 

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