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Anthocyanins and Pinguicula

Joseph Clemens

Staff member
Ever since I began using powdered iron oxide as a media ingredient, I started noticing that many plants, not previously showing much anthocyanin (often misspelled, anthrocyanin) coloring in their leaves, were showing much more noticeable coloration, after being planted in media enhanced with iron oxide.

Several times it was suggested that the iron oxide increased the coloration. Since my usual lighting and general growing conditions already had many of my plants exhibiting nice coloration (to my eye - beauty is in the eye of the beholder), I didn't think much about it.

But, today, with time to spare, I thought to look for any research that might connect the two. I discovered that there was a fair amount of research to indicate that enhancing a plants access to iron and zinc micronutrients, was connected to increased production of anthocyanins.

Below is a photo showing the response I received with Pinguicula gypsicola, right after I first grew out some plantlets in iron oxide enriched media. Another species that shows a strong response is Pinguicula reticulata. Though there may not be a direct correlation, some plants whose leaves were usually a pale green, also became a darker green after the addition of iron oxide.

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Huh, very neat.

How do you source your iron oxide? Do you just add rust shavings to the soil?
I searched the internet and found a source in NY. It was being sold as iron oxide powder (Spanish Red). I don't remember the name of the supplier, but it was a ten pound bag, and as I was shopping, it was the most reasonably priced, including shipping, of all the sources I located, back then.

I discovered that I only needed to use a tiny bit per batch of media. I mix about two to three gallons of media at a time. Sometimes I just add some to one of the media ingredients, like perlite or silica sand.

The ten pound bag, at my current rate of use, will possibly last me about one hundred years, or there-about.

If I were shopping for some, today, I'd likely shop it out through Amazon.com.
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Does it affect the pH of the media?
Here's some info on iron in plants, generally. My guess would be that you should see slightly darker leaves in any plants that you add soluble iron into the soil. But, see also, this discussion, which is far above my understanding of chemistry.

on the flower have you also some colour difference ?
your ping are under artificial light ?

anthocyanins are normally in the water of the vacuole of the plant cell, there are several kinds mainly orange, red-orange, red, purple (blue) that can be combined with other phenols, in fact it is quite complex.

anthocyanins which seems more or less to react metals are purple (blue) and rather with aluminum or magnesium .Now with iron?

nevertheless anthocyanins are very reactive with the nutrition of the plant, the pH of the water and UV enormously. Which often explains the pink, red, dark red leaves intensely UV bombed, which again become green with normal amounts.

Attention some ping always have dark-red leaves (they retain this color throughout their lives, and the phenomenon is reproducible by seeds) in this case? may be symbionts of cyanobacteria, but rest demonstrate.

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