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

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Dose (hypothetical units)

LD50