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I have performed the experiment on effects of hydrogen peroxide on seeds
based on one of the project ideas in plant biology
i have used concentrations of 10,25,35&50ml in 473ml of water respectively
the seeds have germinated in 10ml H2O2 at a maximum and a minimum of 2-3 seeds at 50ml
a little insight on what should happen for the various concentrations with regards to toxcicty of H2O2
would help me know if i made any progress
thanks
what inference should i get?
Moderators: AmyCowen, kgudger, MadelineB, Moderators
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amit_menezes
- Posts: 1
- Joined: Sun Nov 30, 2008 6:41 am
- Occupation: Student
- Project Question: Hydrogen Peroxide and its effects on seed germination
- Project Due Date: 5th December 2008
- Project Status: I am finished with my experiment and analyzing the data
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donnahardy2
- Former Expert
- Posts: 2671
- Joined: Mon Nov 14, 2005 12:45 pm
Re: what inference should i get?
Hi Amit,
This is a really good project idea. I think you have based your project on this outline:https://www.sciencebuddies.org/science- ... p001.shtml
Hydrogen peroxide is an oxidizing agent and will damage plants by breaking double bonds. The most obvious effect of this is bleaching of the plant pigments such as chlorophyll. Are any of your seedlings a lighter color than the others? Are all growing as well as your control (no hydrogen peroxide)? If so, then you did not observe any damage to the plants from the hydrogen peroxide.
Hydrogen peroxide (H2O2) will break down to water and oxygen. Did you notice bubbles forming in your samples that contained hydrogen peroxide? This was due to the formation of oxygen gas. If you are taking/have taken chemistry, can you write a balanced equation for this reaction?
Since the hydrogen peroxide breaks down as it is exposed to molecules with double bonds, there will not be any hydrogen peroxide present in your samples after a few hours. So, if you added the hydrogen peroxide only at the beginning of your experiment, and the seeds have now germinated, then there is no hydrogen peroxide left in your sample.
Here is a scientific journal article that explores the effect of hydrogen peroxide on several aquatic plants: http://www.apms.org/japm/vol22/v22p25.pdf. The authors documented damage to all of the plants a 1 mM and 2 mM hydrogen peroxide. How does this concentration compare with the concentrations that you used?
You stated that you used 10 ml of hydrogen peroxide in 473 ml water. This is equal to:
10 ml/473ml x 3 mg /0.1 ml x 1 mM/34 mg = .018 mM hydrogen peroxide. Can you calculate the other concentrations of hydrogen peroxide you used based on my example? I assume that you were using 3% hydrogen peroxide that is available in drug stores ( 3 grams hydrogen peroxide per 100 ml, or 3 mg/0.1 ml). If you were using commercial 35% hydrogen peroxide, then your actual concentration was much higher.
If you do the calculations, you will find that you should have seen some plant toxicity, at least in the highest concentration that you used. If you did not, then do not worry about it because you did a controlled experiment and you obtained results. However, if the results are not what you expected, then you will need to provide an explanation in your discussion section of your science board. Or, if you have time, repeat the experiment with a different source of hydrogen peroxide. Perhaps you would have different results if you tested your germinated seedlings vs. the seeds before they germinated.
I hope this helps you understand your project a little better. Please let us know if you need more information or additional explanation on the chemistry of this project.
Donna Hardy
This is a really good project idea. I think you have based your project on this outline:https://www.sciencebuddies.org/science- ... p001.shtml
Hydrogen peroxide is an oxidizing agent and will damage plants by breaking double bonds. The most obvious effect of this is bleaching of the plant pigments such as chlorophyll. Are any of your seedlings a lighter color than the others? Are all growing as well as your control (no hydrogen peroxide)? If so, then you did not observe any damage to the plants from the hydrogen peroxide.
Hydrogen peroxide (H2O2) will break down to water and oxygen. Did you notice bubbles forming in your samples that contained hydrogen peroxide? This was due to the formation of oxygen gas. If you are taking/have taken chemistry, can you write a balanced equation for this reaction?
Since the hydrogen peroxide breaks down as it is exposed to molecules with double bonds, there will not be any hydrogen peroxide present in your samples after a few hours. So, if you added the hydrogen peroxide only at the beginning of your experiment, and the seeds have now germinated, then there is no hydrogen peroxide left in your sample.
Here is a scientific journal article that explores the effect of hydrogen peroxide on several aquatic plants: http://www.apms.org/japm/vol22/v22p25.pdf. The authors documented damage to all of the plants a 1 mM and 2 mM hydrogen peroxide. How does this concentration compare with the concentrations that you used?
You stated that you used 10 ml of hydrogen peroxide in 473 ml water. This is equal to:
10 ml/473ml x 3 mg /0.1 ml x 1 mM/34 mg = .018 mM hydrogen peroxide. Can you calculate the other concentrations of hydrogen peroxide you used based on my example? I assume that you were using 3% hydrogen peroxide that is available in drug stores ( 3 grams hydrogen peroxide per 100 ml, or 3 mg/0.1 ml). If you were using commercial 35% hydrogen peroxide, then your actual concentration was much higher.
If you do the calculations, you will find that you should have seen some plant toxicity, at least in the highest concentration that you used. If you did not, then do not worry about it because you did a controlled experiment and you obtained results. However, if the results are not what you expected, then you will need to provide an explanation in your discussion section of your science board. Or, if you have time, repeat the experiment with a different source of hydrogen peroxide. Perhaps you would have different results if you tested your germinated seedlings vs. the seeds before they germinated.
I hope this helps you understand your project a little better. Please let us know if you need more information or additional explanation on the chemistry of this project.
Donna Hardy