Practical: Effect of Plant Hormones on Growth 5.5.6

Question 1

What is IBA

Answer 1

Indole-3-butyric acid is an auxiliary that is often used as a rooting powder

Question 2

What can IBA be used to do?

Answer 2

Investigate the effect of different concentrations of this plant hormone on root growth

Question 3

State the apparatus required for the effect of plant hormones on growth

Answer 3

Indole-3-butyric acid
Alcohol
Measuring cylinder
Beakers
Plant e.g. busy lizzie
Soil or plant compost
Scalpel
Digital balance

Question 4

State the method for the effect of plant hormones on growth

Answer 4

First a 5% solution of IBA should be made - label this solution A
Serial dilutions of the 5% IBA should then be made:
- B = 0.5%
- C = 0.05%
- D = 0.005%
- D = 0.0005%
60 stem cuttings should then be taken from the same plant
Dip the ends of 10 cuttings into solution A and place the cuttings into soil or plant compost
Repeat this with B, C, D, and E
Use final 10 cuttings as a control group by dipping their ends in alcohol
After a set time period carefully remove all the cuttings
For each set of 10 cuttings, carefully remove all the roots and weigh them

Question 5

State the limitations of the practical: effect of plant hormones on growth

Answer 5

Concentration of plant hormone is the only variable that is having an effect on root growth
Cuttings must be obtained from the same species of plant

Question 6

What must be controlled in this practical?

Answer 6

• Volume of water
• Temperature
• Humidity
• Light intensity