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Serial DilutionsSerial DilutionsLD50 of salt solution on Mung beans
Get 2 x 3 inch jewelry
bags jewelry supply store. See
product # 52-002 on second table @
http://www.aajewelry.com/templates/product_list_dropdown_pix.aspx?GroupGuid=5523
Cut piece of paper towel and insert into bag
Staple across the bag such that there is
space for roots to grow
Add 10 to 15 seeds to each
bag
0.2 g/mL NaCl0.2 g/mL NaCl
Stock SolutionStock Solution
Make a 0.2-g/mL NaClNaCl STOCKSTOCK solutionsolution
- Measure 2 grams of salt on balance.
- Get 10ml of water in a graduated cylinder.
- Add 2 g of sodium chloride and add water to 10 mL to beaker… this is your stock solution.
Decide how many different concentrations you want to do.
Don’t forget a control.
You will need one seed bag for each concentration.
You will need one test tube for each concentration.
Get the materials you need.
Add 5 mL of tap water to each of you test tubes
Add 5 mL of Stock Solution to first test
tube using graduated cylinder.
5 ml
Mix the first Tube
Take 5 mL of first tube and add to second
tube
Mix
Repeat until last test tube.
Repeat until last test tube.
Remove 5 ml from your last test tube
All test tubes should have 5 ml
Stock SolutionStock Solution
Squeeze bulb fully, it will not totally fill up that is okay.Pipet has a 5ml capacity but we only need 3 ml.
Write: Stock Solution Write: Stock Solution .2 g/l on bag .2 g/l on bag
WaterWater
WaterWater
Write: Write:
Control 0 g/l Control 0 g/l on bagon bag
0.1 g/mL 0.1 g/mL SolutionSolution
0.05 g/mL 0.05 g/mL SolutionSolution
EtcEtc..
• 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
100
75
50
25
02 4 6 8 10 12 14 16
Per
cen
tag
e o
f p
op
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tio
n k
illed
by
a g
iven
do
se
Dose (hypothetical units)
LD50
