From Cornell University's web page on paraquat
http://www.css.cornell.edu/weedeco/HI/paraquat.html:
"Metabolic pathway inhibited:
Paraquat accepts electrons from photosystem I and is reduced to form the paraquat radical, which in turn reduces molecular oxygen to form the superoxide radical; superoxide then reacts with itself in the presence of superoxide dismutase to form hydrogen peroxide; hydrogen peroxide and superoxide react to generate the hydroxyl radical; superoxide and, to a lesser extent, hydrogen peroxide may oxidize SH groups on various organic compounds within the cell; the hydroxyl radical, however, is extremely reactive and readily destroys unsaturated lipids, including membrane fatty acids and chlorophyll; the hydroxyl radical produces lipid radicals which react with oxygen to form lipid hydroperoxides; such lipid hydroperoxides destroy the integrity of cell membranes allowing cytoplasm to leak into intercellular spaces which leads to rapid leaf wilting and desiccation. "
Granted the use of household peroxide in a topical application probably wouldn't get involved in the photosystem I pathway, but I didn't know, hence the question. If anyone else has any comments on use of household peroxide I'd appreciate your input. Many times advice is passed along that is wrong or detrimental or just plain myth, so I figured to research the use of peroxide before continuing to advise its use. I came across information that one would encounter online in a routine Google search and asked if there was any science behind it. Personally I thought the ideas were laughable, but figured I'd ask a physiologist (if there were any still on the list)
So don't try to bait me with your comments about oxygen in air, Bert. You are just spoiling for a fight and I won't give it to you.
K Barrett N Calif, USA
There is a powerful enzyme, catalase, present in most cells, bacterial,
plant and animal, that converts hydrogen peroxide into water and oxygen real
quick. The peroxide lasts long enough to put the kabash on many bacteria for a
short time, hence its effectiveness in treating crown rot, but if you
incorporate it into media it will quickly disappear. Kathy did confuse me about
whether or not she believes there is oxygen in air. If roots need to respire,
they need certainly need oxygen. Nitrogen is quite inert, reacting only with
nitrifying bacteria such as in legume nodules. I was also surprised to learn
that Paraquat acts by producing peroxide. It is a powerful inhibitor of
cellular respiration; I am unfamiliar with any involvement of peroxide.
Bert Pressman ------------------------------
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