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Adding H2O2 damages HC

2082 Views 10 Replies 4 Participants Last post by  Solcielo lawrencia
I used H2O2 to try to kill BBA but it also had the unintended side effect of also causing HC around the BBA to wither. As well, once it withers down, it won't root again and will suffer for months.

So what does H2O2 do to plants? Does it damage roots and prevent the uptake of nutrients?
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Peroxide is an oxidizer that strips electrons from molecules to release ozone or oxygen. Its electron oxidizing power affects enzymes plants use to make usable form of macronutrients.

Interesting tidbit:
So H2O2 damaged these enzymes? So basically, the plant will need to be replaced since they aren't functioning normally.
H2O2 makes reactive radicals that damage enzymes and other plant tissues. It is naturally made in almost all living cells (all aerobic ones), and cells have a special defense against it - an enzyme called peroxidase that safely disposes of H2O2. Peroxidase is the reason why when you cut yourself and put peroxide on it the liquid fizzes, it is also the reason why H2O2 frequently fizzes when you spot treat certain species of algae.

Can you post some close up photos of the damage? If you can get a few good shots of it I can add them to the and give you credit.
I thought it was catalase that breaks down H2O2.

Anyway, this is what HC looks like. Healthy HC on the right:

Leaves appear to have fallen off and the roots start to wither.
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Thanks for the photos. Very interesting indeed. Though we know it was H2O2, notice how the new and old growth are equally affected - a key indicator that it isn't nutrient related.

Catalase is a specific type of peroxidase and is probably a more precise answer to why cells bubble when exposed to H2O2.

I have to make a correction about the leaves falling off; they don't. They appear to die off from the tips back to the stem, almost like a potassium deficiency but it occurs on all the leaves. The roots die back, too, and the HC can float off the substrate.
Good to know this can be a problem. Just to clarify a few things, firstly hydrogen peroxide does not produce ozone. Secondly, the death of cells could not be due to catalase activity, but the lack of it. Catalase preserves cells by safely decomposing peroxide. If there is just too much peroxide around or the cells were already compromised in some way, the free peroxide may have been left to further react to chew up parts of the cell, triggering cell death and overall damage to the plant.

As I understand it, UV light and dissolved metal ions (iron in particular) aid in breaking up hydrogen peroxide, releasing hydroxide radicals. These radicals immediately react with whatever they can causing a radical chain reaction that can wreak havoc for organic life.

The algae are generally more sensitive to this due to the smaller size and simpler cell structure. They cannot cope with cell loss like more complex life, plants, can. Perhaps HC is just more susceptible to peroxide due to it's size? The small leaves just get demolished and that part of the plant struggles to provide food to grow and repair the damage. This idea might be supported by the fact that the smallest portions of the plant, leaf and root tips, appear to die first.
Both of these reports found that even at a mere 0.2%, brown algae and some cyanobacteria (blue-green algae) could be irradicated. It was also shown that up to 0.6% exhibited almost no negative effect on larger organisms.

Science rant over. :biggrin:

May I ask what concentration of hydrogen peroxide you were using? 3%? If more than that, maybe try a smaller percentage or try diluting it to treat HC.
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Hope you understand I couldn't resist commenting on a chemistry-related post, haha. I do hope you're plants recover quickly from the treatment.
Interestingly heavy metal toxicity harms plants by destroying parts of the photosynthetic mechanism which creates more reactive and damaging radicals.
It was a 3% solution of H2O2, 10 mls concentrated on the rocks. The HC surrounding the rocks were affected.

I've damaged an entire carpet of HC before with H2O2. It won't completely die but it won't grow new leaves. It appears to remain permanently stunted and roots won't take hold. It will eventually sent out new side shoots which will grow normally.
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