1. LD50 of salt solution on Mung beans
Serial Dilutions
LD50 of salt solution on Mung beans

2. Cut piece of paper towel and insert into bag
Get 2 x 3 inch jewelry bags
jewelry supply store.  See product # on second
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

3. Make a 0.2-g/mL NaCl STOCK solution
- 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.
0.2 g/mL NaCl
Stock Solution

4. 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.

5. Add 5 mL of tap water to each of you test tubes

6. Add 5 mL of Stock Solution to first test tube using graduated cylinder.

7. Mix the first Tube

8. Take 5 mL of first tube and add to second tube

9. Mix

10. Repeat until last test tube.

11. Repeat until last test tube.

12. Remove 5 ml from your last test tube All test tubes should have 5 ml

13. Stock Solution

14. Squeeze bulb fully, it will not totally fill up that is okay.
Pipet has a 5ml capacity but we only need 3 ml.

15. Write: Stock Solution .2 g/l on bag

16. Water

18. Water
Write:
Control 0 g/l on bag

19. 0.1 g/mL Solution

22. 0.05 g/mL Solution

25. Etc.

26. 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

27. Percentage of population killed by a given dose
100 75 50 25 2 4 6 8 10 12 14 16
Percentage of population killed by a given dose
Dose (hypothetical units) LD