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antioxidants?
---------- Forwarded message ----------
Date: Mon, 17 Mar 1997 22:27:58 +0000 ( )
From: "Roger S. Miller" <rgrmill at rt66_com>
To: aquatic-plants at actwin_com
Subject: antioxidants?
A quick note: I lurked on this list for a while starting about 2 years
ago. At the time the list was deeply involved in substrate wars. I
dropped my subscription for sometime and only recently started reading
again. What do I find? Substrate wars!!
I did a quick search in some recent archives of the APD for the term
"antioxidant" and didn't find it. So I thought I'd get it in here.
I've got a problem in one of my tanks, where the leaves of several plants
(echinodorus bleheri? hygrophilla corymbosa? anubia barteri nana and java
fern) start showing small lesions almost as soon as they reach full
development. The lesions develop into holes which get gradually larger
and coalesce, finally leaving little more than a few frayed veins.
Cryptocoryn balansae and bolbitis in the same tank are uneffected. The
lesions are initially dark on the java fern and light in the other plants,
but in all cases they turn dark as they get bigger. The holes develop at
different rates in different plants; rapidly in the hygrophilla and slowly
in the anubia. This has been goin on for about a year and a half.
I originally thought this was damage from a breeding pair of M. festivum
cichlids. I got rid of the fish, but the problem persisted. I've
considered a variety of water quality problems including too-high nitrate
(a problem according to some sources) and nutrient deficiencies. Reducing
the nitrate levels hasn't changed anything, and my local water carries
enough Mg and K that I don't believe that they could be deficient. Also,
I use the same tap water in my other 4 planted tanks with the same
problem.
Any suggestions? If more details are needed, I can provide lots.
One thing I noticed recently was that the damage only effects parts of the
leaves that are exposed to light. Areas of leaves that are overlapped by
other leaves are not damaged. That started me thinking about direct
damage from the lights (Philips ultralume 5000k) perhaps due to UV from old
tubes. Has anyone run into something like that?
I also started wondering about damage from the buildup of oxygen in the
plant tissue. The tank bubbles like a glass of alkaseltzer (well, almost)
when it gets going, and the O2 levels in the plant tissue must be huge.
I suppose damage from either source would normally be controlled by
antioxidants. Can something suppress the formation of some important
antioxidant and lead to the leaf damage I see?
On an (I think) unrelated note, I recently found little (3 mm long)
limpets in this tank. They look something like scale that you might find
on fruit trees, but they move about and from the bottom they look rather
like snails. Are these guys a problem? Marine limpets are all algal
grazers as near as I can tell, but I haven't been able to find much about
freshwater limpets.
Roger Miller