The Effects of Caffeine
on Plant Germination
By: Erin Chandler
Question
• How will different amounts of caffeine
exposure affect the growth and
germination of radish seeds?
Background Information
•
#1 drug in America
•
Caffeine is better known as trimethylxanthine
•
The chemical formula of trimethylxanthine is C8H10N4O2
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Naturally made in some plants
•
Used in sports
•
Caffeine and the brain
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Growth hormone or inhibitor?
•
Raphannus Sativus
•
Growing conditions
•
Process of germination
Hypothesis
• If seeds are exposed to caffeine
solutions of various concentrations,
then those exposed to the highest
concentration will have higher
germination rates and longer root
lengths then those exposed to solutions
with lower caffeine concentration.
Materials
• bleach
• dropper
• distilled water
• gloves
• 5 beakers
• 200mg caffeine pill
• mortar and pestle
• radish seeds
• 20 Petri dishes
• 12 pieces of filter paper
Procedure
•
Wear gloves while making the bleach solution. Put seeds in a bleach/water solution and rinse
•
Label beakers 1-5 and fill beaker 1 with 100 mL of water
•
Crush caffeine pill and put it in beaker 2 with 100 mL of water, stir
•
Take 10 mL from beaker 2 and add to beaker 3 along with 90 mL of water, stir
•
Take 10 mL from beaker 3 and add it to beaker 4 along with 90 mL of water, stir
•
Take 10 mL from beaker 4 and add it to beaker 5 along with 90 mL of water, stir
•
Label Petri dishes according to caffeine concentration and then trials 1-4
•
Soak filter paper in 3 mL of solution and place in appropriate Petri dish
•
Put 10 radish seeds in each Petri dish
•
Put Petri dishes in a dark enclosed area for 3 days and observe
Variables
• Control: seeds exposed to distilled water
• Independent Variable: amount of caffeine
in each solution
• Dependent Variables: amount of seeds
that germinate, and root lengths
• Constants: amount of solution on filter
paper, temperature, number of seeds in
each Petri dish, temperature of water
Data
Seeds Germinated
Data (2)
TTEST
Caffeine concentration
Caffeine against control
0.002
0.000101
0.02
0.000000
0.2
0.000005
2
0.000101
Discussion
•
The data in this experiment showed that, the caffeine did cause a change in the
way the seeds germinated and grew
•
The solution with the most caffeine had the least amount of seeds germinated
and in the control the most amount of seeds germinated
•
The t test showed that all data can be interpreted because all results are lower
then .05, the conclusion that can be drawn according to the t test is that caffeine
has a major effect on the plant’s germination
•
The hypothesis was not supported by the results generated in this experiment
•
These results show how caffeine has a negative effect on the seeds, and that
stimulants do not help the growth of plants
Changes and Further
Experimentation
•
If this experiment were to be conducted again, more trials would have been
very beneficial
•
It also would have helped to put the Petri dishes in plastic bags so that the
seeds did not dry out. This would have allowed for more growing time for the
seeds which would result in more data and more accurate results. Also,
testing even more amounts of caffeine on the seeds may have shown more
significant results so that better conclusions could have been drawn
•
If a person wanted to take this experiment further they could have
experimented with different kinds of seeds, put the seeds in different
environments or tested the seeds with other drugs similar to caffeine
Thank You
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Brian, M., & Bryant, C. W. (n.d.). How Caffeine Works. Retrieved October 6, 2010, from Discovery Health website:
http://health.howstuffworks.com/
wellness/drugs-alcohol/caffeine1.html
Caffeine. (n.d.). Retrieved January 30, 2011, from chemBlink website:
http://www.chemblink.com/products/58-08-2.htm
Enblogopedia. (n.d.). What are the effects of caffeine? Retrieved September 5, 2010, from Enblogopedia website:
http://www.mycaffeineaddiction.com/
the-effect-of-caffeine-on-plant-growth/
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Greenaway, T. (2001). Plant Life. Austin, TX: Raintree Steck-Vaughn Publishers.Growing radish from seed. (2000). Retrieved
September 5, 2010, from
GardenAction website: http://www.gardenaction.co.uk/fruit_veg_diary/
fruit_veg_mini_project_june_1b_radish.asp
Olympic Gold? A New Effect of Caffeine Boosts Performance. (2010, June 30). Science Daily. Retrieved from
http://www.sciencedaily.com/releases/2010/
06/100629193123.htm
Reid, T. (n.d.). Caffeine-What's the Buzz? National Geographic. Retrieved from
http://science.nationalgeographic.com/science/health-and-human-body/human-body/caffeine-buzz.html#page=8