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Nitrate Starvation, Red Colouration promotion

WaterCulture

Seedling
Joined
27 Feb 2021
Messages
19
Location
Liverpool, England
Hi everyone, hope you are well.

I know its a tried and tested measure that a combination of high lights, co2 and All nutrients, while having minimal Nitrate promotes red colouration by deactivating the gene responsible for green chlorophyll.

However my tank has a nice mixture of plants with the potential to be very red (H'ra, AR Mini, Red tiger lotus, lugwigia super red etc)
but also has alot of green plants which will never turn red.

So my question is, while low nitrates are advantagous to my reds, will my greens suffer ?

Thanks
 
Hi
Welcome aboard.....personally I have found limiting Nitrate to below 10ppm induces leaf deformation with my Cryptocoryne!
Plus it tends to decrease the green colouring in certain plants....that's my observations.
hoggie
 
So my question is, while low nitrates are advantagous to my reds, will my greens suffer ?

Well the reds may look better, however the great red colour is due to a deficiency, which whilst it looks good doesn't mean its doing the plant any good, so all plants are potentially suffering.

Natures amazing colour bloom in the fall of many plants and trees is after all the terminal death throw of toxins in the leaves after all
 
I know its a tried and tested measure that a combination of high lights, co2 and All nutrients, while having minimal Nitrate promotes red colouration by deactivating the gene responsible for green chlorophyll.
NO3 deficiency does not genetically deactivate chlorophyll production. Shortages of Nitrogen simply prevents the plant from producing sufficient quantities of the chlorophyll molecule as the molecule is constructed around a Nitrogen-Magnesium chlorophyll ring. The enzymes and the precursors that produce the chlorophyll are themselves constructed of these rings, so lack of Nitrogen in general disables the production due to unavailability.

Nitrogen starvation also limits growth, curtailing the production of amino acids, which are responsible for protein construction. Restricting Nitrogen can causes plant health to deteriorate sufficiently to render it susceptible to algal attacks.

A very red plant is actually a sign of low Nitrogen stress. Having said all that, many only ever consider the restriction of NO3 as their path to redder plants without ever considering that Nitrogen is also bound in NH3/NH4, both species of which are prevalent to a much higher degree in the sediment than in the water column and both have a much higher Nitrogen assimilation rate in plants than does NO3.

Cheers,
 
A very red plant is actually a sign of low Nitrogen stress. Having said all that, many only ever consider the restriction of NO3 as their path to redder plants without ever considering that Nitrogen is also bound in NH3/NH4, both species of which are prevalent to a much higher degree in the sediment than in the water column and both have a much higher Nitrogen assimilation rate in plants than does NO3.

Cheers,
Dear ceg
thank you for your detailed reply
but I can't understand last paragraph
do you mean that
replacing the source of N to be NH4/NH3 instead of NO3 will be good for both red and green ?
 
Dear ceg
thank you for your detailed reply
but I can't understand last paragraph
do you mean that
replacing the source of N to be NH4/NH3 instead of NO3 will be good for both red and green ?
Hi Mohamed,
Nitrogen uptake and assimilation are tricky. On one hand, the N that is bound in NH3/NH4 is very easy for plants to use and is more abundant per unit weight. For example, NH4 by weight is mostly N since the Hydrogen (H) is the lightest element. In NH4 78% of that weight is N, so in 1 gram of NH4 there is 0.78 gram of N.
In NO3 only 22% of that weight is N, so 1 gram of NO3 yields only 0.22 gram of N.

Furthermore, the energy required to convert, for example NH4, to the chemical amine (-NH2) is very small. It's then very easy to produce amino acids which are used to build proteins.
Producing the same result using NO3 is a more elaborate procedure separating the 3 Oxygen atoms from N. This requires extra enzymes and extra steps so the energy required to use N in this case is less efficient.

On the other hand, there is a downside. Whereas NO3 is non-toxic and can be stored in huge quantities within the plant tissue, NH4 is more toxic and NH3 is extremely toxic. Storage within the plant tissues therefore requires elaborate procedures using internal methods of chelation, greatly reducing the efficiency of NH3/NH4.
As a result of this toxicity, NH3/NH4 uptake is carefully regulated and if both NH3/NH4 and NO3 are present in the water column the plant will selectively uptake NO3 when the concentration level of NH3/NH4 in the water column is high.

Most commercial fertilizers therefore use a combination of NH3/NH4 and NO3.
It would NOT be a good idea to unilaterally substitute NH3/NH4 for NO3, but instead to add only small amounts to the NO3.
In a tank with animals I am fundamentally opposed to the use of NH3/NH4 due to this toxicity issue.
In a plants only tanks there is less of a concern and yes, you can get better performance, better growth, darker greens etc. by adding small amounts of NH3/NH4, however, careless application can also trigger algal blooms.
In the tank animal and plant waste break down into NH3/NH4 already and we can add as much NO3 as we want without any worries whatsoever, but we cannot do the same with NH3/NH4.

Hope this clarifies.

Cheers,
 
Last edited:
You need to tell my plants that low nitrogen makes them red. This is with 2x EI dosing levels, due to large plant mass, and they seem to have no problem with deep reds. Maybe excess nitrogen makes plants red ?

1614674956638.png
 
You need to tell my plants that low nitrogen makes them red. This is with 2x EI dosing levels, due to large plant mass, and they seem to have no problem with deep reds. Maybe excess nitrogen makes plants red ?

View attachment 164004

Ditto this - I personally think there are enough naturally red plants available to render forcing it by nitrate limitation somewhat redundant.

I have Ludwigia Palustris and Alternanthera Reineckii that stay very red under EI dosing.

That said, I also think the colour rendition of the lighting plays a part. Under the Chihiros RGB light (and I assume similar with the ADA variants), and also under some tubes I've seen, reds really look very red indeed, but the exact same stems can look very dull and subdued under more common white LED lights - so @WaterCulture you may want to try a Chihiros WRGB II or similar as an alternative method to get the visual reds you're seeking.
 
If I’m not mistaken, nitrate limitation only affects a small group of red plants, and ludwigia red/puruensis isn’t part of that group thankfully. My ludwigia gets stronger coloration the closer it is to the light.
 
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