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Re: Does a lack of nitrate cause small, distorted leaves?

On Mon, 3 Apr 2000, Ryan Mills wrote:
> I'm beginning to think so.  While I was busy working
> on a law school project, I didn't feed my fish much
> even though I still did dose with the Flourish and do
> water changes.  I noticed some tiny and deformed
> leaves
> on some plants.  Checking the nitrate, I found it to
> be zero.  I'm sure there was plenty of calcium,
> potassium, and boron available to the plants.  I added
> some nitrate (now 5ppm) and I'm betting things get
> back to normal.  Any thoughts?

I don't think that small deformed leaves are the typical symptom of
nitrogen shortage. Nitrogen is a mobile nutrient, so the symptoms are
supposed to appear first on older leaves.  The older leaves typically
develop interveinal chlorosis then drop off or die back from the end.  
The chlorosis is more readily observable in plants that are normally dark
green and that hold their leaves quite awhile after onset of the symptoms.  
If the nitrogen shortage becomes chronic then maybe symptoms (general
chlorosis?) will appear in new growth as well.

I see symptoms of nitrogen shortage first in fast-growing heavy feeders
like Echinodorus. If the shortage isn't fixed then symptoms will appear
later in slower growing plants.

I see small but usually undistorted leaves in generally weak plants grown
under chronically poor conditions.  Nitrate is often very high under those
conditions because plant growth is too slow to keep up with the nitrogen
added with fish food.

Distorted leaves are something else.  Aside from calcium and boron
deficiencies it's possible to see distorted leaves caused by severe
imbalance among Na+, K+, Ca++ and Mg++, or (as Paul Krombholz described
some time ago) by toxins.  Hungry fish nipping at new growth and other
forms of damage might also cause new leaves to be small and distorted.

Roger Miller