Materials

• IAA solution, 0.01% w/v = 100 parts per million (ppm)

• Radish seeds

• 8 Test tubes or Bottles

• Distilled Water

• 8 Petri Dishes

• 8 Acetate Grids and Cotton wool

ACTIVITY

To investigate the effect of IAA growth regulator on plant tissue

Method

A. Preparing different concentrations of IAA

1. Label the 8 Petri dishes, droppers and bottles 1, 2, 3 . . . 8

2. Using a syringe, add 10 ml IAA solution to Bottle 1.

3. Using another syringe, add 9 ml distilled water to each of the bottles numbered 2 to 8.

7654321 8

4. Using Dropper 1, remove 1 ml IAA solution from Bottle 1 and add it to Bottle 2.

Place the cap on Bottle 2 and mix.

5. Using Dropper 2, remove 1 ml IAA solution from Bottle 2 and add it to Bottle 3. Mix.

6. Using a different dropper each time, repeat this procedure up to Bottle 7.

7. After mixing Bottle 7, remove 1 ml so that each bottle now contains 9 ml of solution.

8. Leave Bottle 8 as it is, with just 9 ml distilled water – it will act as the control.

Serial dilution—making different concentrations of IAA

Tube 1 2 3 4 5 6 7 8

IAA10 mls --

control

Water -- 9 mls 9 mls 9 mls 9 mls 9 mls 9 mls 9 mls

IAA conc

102 101 100 10-1 10-2 10-3 10-4 0

*ppm 100 10 1 0.1 0.01 0.001 0.0001 0

Serial dilution—making different concentrations of IAA

*ppm = parts per million

7. Draw a graph of the % stimulation and inhibition of root and shoot growth against IAA concentration.

Put IAA concentration on the horizontal [X] axis