# Nutrient uptake at night?



## Yo-han

Do plants take up nutrients (NO3, PO4 or anything else) at night?


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## AaronT

I've wondered this myself. I sometimes dose iron at night with the thought that it won't be broken down by the light.


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## Yo-han

Yes indeed, the coloration from my tracemix is gone the next morning. Did plants use it? Or did it broke down and got lost?


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## niru

Guess not.... Only with lights on would they feel hungry.

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## art_b

I asked a similar question on the Seachem forum http://www.aquaticplantcentral.com/forumapc/seachem/87347-dosing-aquavitro-synthesis.html#3

As long as there is plenty of ambient light, plants will be able utilize nutrients.


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## jerrybforl

There has to be light present for plants to photosynthesize. If there isn't, they are dormant. So if there is no light at all, they can't uptake any ferts. 

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## Yo-han

Without light they aren't dormant. They use O2 and release CO2. So maybe some nutrients can still diffuse in/out of the leaves was my thought...


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## Zapins

Many of these nutrients use transporter proteins. These proteins don't require light to work, though some require ATP. ATP is a byproduct of photosynthesis. The important thing to understand is photosynthesis produces sugars only, it is not directly involved in using nutrients for building new tissue. These sugars can be broken down at any point to make ATP, this occurs day or night and is in fact the reason plants put out more CO2 at night. With this in mind if the ATP is there for absorbing nutrients at night then I see no reason why plants would or could stop absorbing nutrients at any point of time.


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## OTPT

Just stumbled upon this. 

http://www.waterboards.ca.gov/water...lta/docs/cmnt081712/sldmwa/feijooetal2002.pdf

"A preference for amrnonium over nitrate has also been observed in other subinerged macro-phytes, such as Ceratophyllum demersum (Toetz,1971) and Myriophyllum spicatum (Nichols &Keeney, 1976b). In C demersum, nitrate uptake has been found to correlate with light intensity,practically ceasing in the dark, while ammonium uptake was continuous and decreased only slight-ly at night (Toetz, 1971)"


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## Yo-han

Thnx for sharing! This is the kind of info I needed.


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## h4n

very interesting!


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## Zapins

Very interesting!

I wonder if this holds for all / most aquatic plants?


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## niko

Another interesting point. Look at page 100. It says:
"..In Pampean nutrientrich streams, water flow provides an abundant and continuous supply of nutrients..."

What levels are considered "abundant"? The numbers in the table on page 101 show P=0.1 to 0.3. If P is measured in
mg/L (or ppm) and if that is "abundant" then see how "abundant" is your tank's water and ask yourself why. Same goes for the Nitrogen in the streams listed in the table.


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## Trail_Mix

*Iron and Light*

I've forget who, but I remember one person who suggested dosing macros during the day and micros at night. I don't know if there's any real scientific reasoning behind this method though, and I also don't know if he meant that you should dose the micros in the evening before lights go out, or at night.

Also, what's the correlation between Iron and lighting that was mentioned above? I was not aware of this, how does it work? Personally, I dose Seachem Iron, but always dose during the day. Should I change this? What about Trace Elements?


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## Yo-han

I think that had more to do with light breaking down the chelators of the traces. Dosing it just after light out it will be chelated longer thus longer available. Dosing the macros during the day has probably to do with not dosing them at the same time as the micros. I used to do this before, now dose everything in the morning a few seconds apart, no problems!


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## OTPT

Hi, just found this one: PO4, K, Ca, and Mg uptake, light vs shading/dark. 
The graphs are on page 153-154.
http://ir.ihb.ac.cn/bitstream/34200...ersed macrophyte Myriophyllum spicatum L..pdf



Zapins said:


> Very interesting!
> 
> I wonder if this holds for all / most aquatic plants?


Yea, me too.


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