Re: Essential nutrients (Cr ?)

> From: krombhol at felix_TECLink.Net (Paul Krombholz)
> Date: Sun, 12 May 1996 22:22:39 -0500
> Subject: Re:chromium as a nutrient
> Alok wrote, Sat., May 11:
> >Regarding Nutrients:
> >        On top of low Fe and low light as causes for lack of brilliant
> >red, and if I remember correctly, the trace elements Mg, Mn (for all
> >plants) and Cr (for RED plants).
> >        I don't remember where I heard it, but if anyone can confirm the
> >need for Chromium with another source, please do.
> Chromium is not known to be an essential element as far as I know for any
> plants.

Chromium is not an essential nutrient. There is not much chance that Cr will 
ever be considered as one. That goes for MOST aquatic plants. With this said,
there may be some aquatic plants that derive a benefit by having Cr available 
to them. Those elements are called  "beneficial elements" because plant does 
not need them for normal growth and reproduction.
    You know how hard is to discover in some cases what element is deficient
in your tank. Proving the role of so called beneficial elements will be no doubt
much harder.
    For example Cobalt is considered a beneficial element in legumes because it 
helps the plant with nitrogen fixation. Now in the soil without available 
nitrogen that may be considered "essential". It may also inhibit ethylene 
formation (Samimy, 1978), and extend the life of cut roses (Venkatarayappa et 
al., 1980). Silicon deposited in the cell walls has been found to improve  
drought tolerance and resistance to fungal infections  (sorry to have switched
off topic to terrestrial plants :-)  ). 
     There is still a fair bit of gray area......
By the way Nickel has just recently won the status of an essential trace 
Franc Gorenc                        franc at golden_net
Kitchener, Ontario               http://www.golden.net