Serial%20Dilutions

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Serial Dilutions
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Get 2 x 3 inch jewelry bags jewelry supply
store.  See product 52-002 on second table _at_
http//www.aajewelry.com/templates/product_list_dr
opdown_pix.aspx?GroupGuid5523 
Staple across the bag such that there is space
for roots to grow
Cut piece of paper towel and insert into bag
Add 10 to 15 seeds to each bag
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Make a 0.1-g/mL NaCl STOCK solution - Add 1 g of
sodium chloride to beaker and add water to 10 mL
0.1 g/mL NaCl Stock Solution
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Get as many test tubes (minus two controls) as
you have plastic jewelry bags for your experiment
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Add 5 mL of water to each of you test tubes
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Add 5 mL of Stock Solution to first test tube.
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Mix the first Tube
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Take 5 mL of first tube and add to second tube
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Mix
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Repeat and remove 5 ml from last tube and discard
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Using a 5mL disposable pipette, add 3 mL from
stock solution to a bag. This is one control bag
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Using a 5mL disposable pipette, add 3 mL Water to
a bag. This is one control bag.
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Using a 5mL disposable pipette, add 3 mL from
your dilutions to each remaining bag. These are
your variables.
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Stock Solution
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Water
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0.1 g/mL Solution
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0.05 g/mL Solution
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Etc.
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• Put all the bags upright in the beaker that had
  the stock solution.
• Put in dark area for one about one week
• Determine the percent dead for each
  concentration.
• Graph with the dead on the y-axis and
  concentration on the x-axis.
• Determine the LD50 or the concentration where 50
  of the seeds did not germinate

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