Expert: Dana Krempels, Ph.D. - 1/6/2008

Question
Adrian decided to conduct an experiment on the affects of gibberellins on plant growth for a science project. He chose garden peas for his experiment. He grew a dwarf type of garden pea and sprayed half of his plants with gibberellin every day for three weeks after germination. The other half of the plants were not sprayed. At the end of his experiment, he measured the height of all of the plants. He found that the dwarf plants that were sprayed with gibberellin were much taller than the unsprayed plants. He concluded that gibberellin increases the growth rate of pea plants.

a. How could you modify Adrian's conclusion to make it better reflect the results he obtained?

b. How could Adrian have designed his experiment differently to make it a better experiment?

I'm totally lost on this one. can you help me please. thank you so much

Answer
Dear Melissa,

I can't answer your homework question, but I can give you a hint.  Dwarf pea plants have an inborn error of metabolism that interferes with their normal production of gibberellin.  

What if Adrian had chosen two different types of pea plants--dwarf and non-dwarf--and then sprayed them all with gibberellin and control solutions?  What would you expect to happen, given what you know about the reason for dwarfing in peas?

I hope that helps you!

Dana