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Re: nickel allergy and Flourish



Jared wrote:
>Also of interest
>is the change in percent composition of those elements in Trace (vs. the
>Flourish formulation) -- I was told this was to reflect information in
>Diana Walstaad's book, "Ecology of the Planted Tank."

Jared or anyone else, please report the percent concentration of Ni and Co
in Flourish. 

Knowing Diana's thoroughness, I had to check this out. I did find her
mention on p. 103 of nickel as it relates to "the enzyme urease." I could
not find her mention cobalt nor of the percent needs of plants.  Not having
a clue about urease, I did a little checking on the web. 

I was a bit surprised to find out that nickel has just recently won the
status as an essential trace element for plants. This is attributed to the
Agricultural Research Service Plant, Soil and Nutrition Laboratory in
Ithaca, NY. 

"It is required for the enzyme urease to break down urea
to liberate the nitrogen into a usable form for plants. Nickel is required
for iron
absorption. Seeds need nickel in order to germinate. Plants grown without
additional nickel will gradually reach a deficient level at about the time
they
mature and begin reproductive growth. If nickel is deficient plants may
fail to
produce viable seeds."

OK, this MAY be important for certain aquatic plants. However, not many of
us are concerned about seed formation. 

Texas A&M Horticultural Sciences includes Nickel as well as Chloride as
plant micronutrients. They are at the end of the micronutrient list with
iron at the top, so I assume these are needed in the smallest trace
amounts. This would means less than 0.001 ppm. Thats pretty small. 

Moreover, on the TAMU web page which lists the 17 essential elements
required by plants
http://generalhorticulture.tamu.edu/lectsupl/Nutrient/nutrient.html, TAMU
says that it is a ubiquitous metal and does not warrant further discussion.
Hmm... I wonder who else said it might be ubiquitous :-) 

I checked for some typical concentrations and found data from the
California Department of Health Services which shows that recent levels of
nickel in drinking water averaged 26 g/L. Those levels are the same as
~0.03 mg/L (or ~.03ppm). Until we see the composition of Flourish, we wont
know for sure. But I would bet my precious red horemanii that typical tap
water has more than what Seachem is providing. 

TAMU does not even list cobalt, but this doesn't mean that plants cant use
it. A little checking on the internet finds a Japanese firm whose web page
says:
"Cobalt is required for nitrogen fixation in legumes and in root nodules of
                      nonlegumes."  

I am not currently keeping those plants in my tanks. :-) [I do, however,
have some that are setting seed]

Neil