Step 3

Data collection and Results                 

During the week the seedlings, having been given water, warmth and light,have germinated and developed SHOOTS and ROOTS.

The next task was to see how much effect, if any, the IAA had on the development of theses shoots and roots.

The video shows the Petri dishes starting on the left with the 0.0001 ppm IAA to the 0.0 ppm IAA control (open dish) on the right. The form at the end shows the way the information on lengths was collated.

This was done by measuring the lengths of the shoot and root of each of the five seedlings in each of the Petri dishes containing the different IAA concentrations.

Once they were all measured and the information written down separately for shoots and roots an average growth length for shoots and an average growth length for roots was calculated for each Petri dish/IAA concentration.

These average growth lengths for each set of shoots or roots was then compared to the average length of growth for the corresponding shoot or root control which contained no IAA. This was done using the formula below:

Percentage of
stimulation/inhibition = { Average sample shoot length - Average control shoot length } x 100
                                        ---------------------------------------------------------------------------
                                                               Average control shoot length

Of course, for roots, the roots values were used  :-)

By doing this it was possible to determine to what extent, expressed as a percentage of the control growth lengths, did the IAA treatment effect the shoots or roots in comparison to the control.

The resulting data were placed in graph form for easier interpretation;

If you consider the zero % line to be the Control with no IAA in it then you can read the effect of the IAA concentrations relative to this

No data is of use unless it is given some interpretation to determine whether it upheld or refuted you original hypothesis; What occurred? Why did it happen that way? Was there something that could have been wrong with the experiment? The interpretation of the results along with other questions will be the subject of the next blog.