# About nutrient reserve in plant? Luxury Uptake



## Glouglou (Feb 21, 2006)

I start an high tech aquarium for around 2 years. My result are Ok, but not fantastic.

One of the concern I have is the reserve factor of plants (show below in %).

The high tech mind keep pushing nutrient to plants and probably fill those reserve pretty quick.

Nobody talk about that. And nowhere is mention to give some time out to the poor obese plant.

Maybe in the el-natural side, this is a consideration?

What you think about this?

and how you incorporate this knowledge to your own method?


N — Nitrogen — 1000

P — Phosphorus — 1000

K — Potassium — 1000

O — Oxygen— 0.02

C — Carbon — 1000

H — Hydrogen — 0.02

S — Sulphur — 50

Ca — Calcium — 10

Mg — Magnesium — 10

Fe — Iron — 1000

Other Trace elements — 1000
__________________


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## Edward (May 25, 2004)

Do you mean "Luxury uptake"?


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## Glouglou (Feb 21, 2006)

*Yes Luxury Uptake!*

These number show in % of what is needed the ability of the plant to stored or not some nutrients.

I think, by running the tank always with high light, high Co2, high nutrient we running the plant on Full, all the time. I think that lot of problem out there is cause by excess and, blockage by excess, more than deficiency.

If the plant have those reserve it's probably that in a natural environment they sometimes used them.

Maybe we need to be leaner on the stuff. Anyway dosing any nutrient should be made on the uptake rate and not on any other measurements. Like that the dosing regimen adapt itself to any tank.

I will develop something on that......

Edward, I'm in total accord with you on your comments in the thread : 
*On going troubles...Lights and Co2 , here*

By playing chemist with our tanks, we sometimes forget the basic.
• Amount of light and duration (photoperiod and real amount of light in natural biotope)
• Nutritive substrate
• Water movements (Prandtl boundary) and oxygenation
• PH vs different nutrient absorption and ph vs biologic filter
• Plant luxury uptake and uptake rate
and more.....

Personally I'm going back to the PMDD kind of approach, but taking in consideration the luxury uptake ( mean I can shoot a little bit more or less of some nutrient for some period) all that can be follow by going a little bit lower than needed periodically to let the plant used is reserve and prevent build-up in plants and water.
The El-Natural kind of way, minus .... the restrictions.


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## Edward (May 25, 2004)

The next step is to divide the elements into immobile, mobile (and partially mobile). 

Immobile are elements that must be present all the time, Ca, Fe, Mn, Cu, Bo, S, Zn.
Mobile are elements that are not necessary to be present all the time, N, P, K, Mg, Mo, Cl.
(Partially mobile C)


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## dennis (Mar 1, 2004)

I think it is important to remember that while plants may be naturally adapted to use luxary uptake from time to time, they probably do not look very attractive while they are using them.

I don't quite understand why mobile elemts do not need to be in constantly present? The fact that it is mobile means the plant will translocate it from "older" growth in order to assimilate new tissue else where. As far as the plant is concerned (in general) the only important part in the growth meristems/apex and these should be protected at all costs- from the plants point of view. Having a mobile element, say Nitrogen, unavailable in sufficient supply means that the plant will start stripping "newer" growth of N. Since N is an essential element in building Rubisco and every amino acid, why would we want the plant to start eating itself to maintain a stagnant state.

I understand what you mean about excess leading to problems in some cases but I do not feel the solution is to occasionally starve the plant and make it use its stored resources. Besides, mobile elemnts will be pulled from the stores, regardless of enviromental levels as the plant grows, and immobile elements will be very difficult for the plant recapture. Plants relocate nutrients for survival, not for propogation.

I completely agree that lighting is probably the biggest factor. In my opinion, the real issue is not that the plant is not relocating its stores but that we are pushing it so hard with our lighting they they are forming weak, unorganized growth structures. Consider why you don't fertalize your yard or field with nitrogen in the late fall. The increase of N will drive growth at a point when the plant needs to allow itself to winter harden. The increased speed in growth essentially meants that the vegitative structures are less organized and weaker. The spacing is bigger, on a cellular level. Amino acids and other complex molecules are often missing peices or small subgroups, even RNA (if I remember correctly) is weaked by this intense growth. Now, in our aquariums, we don't want our plants to go dormant and the temperature does not drop, which naturally would slow growth. Lighting is really the limiting nutrient in our setups (generally speaking concerning the high growth, high tech setups this is about). CO2 is very high becasue that is a natural necessity withthe high light.

IMO, if you want healthier plant, don't starve then of the essentiel building blocks, make them use those blocks slower by decreasing light. I don't have it in me to talk about decreasing CO2 rates.....

I will question the alleochemical idea though, if it were really so powerful and important/prevelent, why do algae chocked, nutrient saturated bodeis of water- chocked with insanely fast growing plants like Hygrophilia, etc that grow many inches a day, have so much algae also. If the nutrients and natural light are creating the extreemely high growth rates, the plants should in theory be healthy and thus produce planty of alleochemicals. What are these chemicals? If we can tell exactly what chain of amino acid/hormone will induce flowering(or any other process) why don't we know these alleochemicals yet.

Sorry, I know that I sound doubtfull and I do apologize for that. Perhaps I should simply ask if we know what these chemicals are becasue I have not read of them, though I certainly don't read as much as I would like too.


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## Edward (May 25, 2004)

Hi dennis

Luxury uptake has nothing to do with attractiveness. You can't tell if plant took 500x more Fe or 50x more. Mobile elements don't need to be in constant supply (in water or substrate) because there is plenty in the plants. If you miss one dose, you see dead plants? No. 
People bring home new plants loaded with nutrients, don't know about dosing and then wonder why the plants look bad after several weeks time. "They were fine and suddenly they look bad, what happened?" Well, they consumed the extra nutrients taken as luxury uptake from before. 




dennis said:


> I completely agree that lighting is probably the biggest factor. In my opinion, the real issue is not that the plant is not relocating its stores but that we are pushing it so hard with our lighting they they are forming weak, unorganized growth structures.


 No, I think plants favor light, very strong light. I have grown plants under 0.65 Wpg and also under 250 Watt MH. The lower light works fine at 10 hours a day. The higher at 6 hours a day. So the problem is not the intensity, it's the lighting period. 




> Lighting is really the limiting nutrient in our setups (generally speaking concerning the high growth, high tech setups this is about). CO2 is very high becasue that is a natural necessity withthe high light.


Statement that CO2 deficiency causes algae is baloney. I run 250 Watt MH with no CO2 and have no algae. Please explain?




> I will question the alleochemical idea though, if it were really so powerful and important/prevelent, why do algae chocked, nutrient saturated bodeis of water- chocked with insanely fast growing plants like Hygrophilia, etc that grow many inches a day, have so much algae also. If the nutrients and natural light are creating the extreemely high growth rates, the plants should in theory be healthy and thus produce planty of alleochemicals.


They do produce it, but you keep destroying it with water changes. 

Thank you
Edward


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## dennis (Mar 1, 2004)

Re alleochemicals: I am not refering to our aquarium but to natural ecosystems. I have no proof either way but have never seen real proof either so I can't comment anymore on that subject.

I understand what you are saying about luxury uptake. Yes, plants can and will use them when the situation requires and yes, it can allow a new plant to survive harsh times, neglect, etc. My argument was against the idea of letting them use those reserves occasionally. I can see no logical need for that. It sounds like the same concept as the noon "siesta" no light for a few hours thing. All it will do is cause some plants to slow in growth, think it is time to seed or flower, etc. The real key with any approach is consistancy, IMO. High fert/light/CO2 tanks can very easily become inconsistant in levels of anything, causing poor plant health. The comparison of using luxury uptake to letting a car's gas tank run almost empty is not a good analagy. You should never let the tank run almost empty as the sludge and rust at the bottom will foul sending units and filters which leads to a decline in engine performance, er plant growth, er...

My main point about allowing plants to use luxury supplies of mobile elements is that some mobile elements, like nitrogen are retranslocated from almost new growth first, ie leaves near the plants top. I completely understant you feelings about not overdosing, but still dosing should be consistant and sufficient.


I do agree with you about lighting durations being important and I was getting at that point, I just did not explain myself well. I do stick behind the fast growth= unhealthy, disorganized/weak growth. That is a common understanding in agriculture and I really believe it applies to our high intensity everything aquariums, though obviously I have no direct proof of that.


You obviously have a system that works for you and I am not trying to say you are wrong. Please understand that. I wish I could observe one of your 6wpg no CO2 tanks from its initial setup and through out the course of its life.


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## HeyPK (Jan 23, 2004)

Typical submersed stem plants become deficient in nitrogen when the tissue content drops below 1.5% (dry weight). This value (1.5%) is known as the critical value for nitrogen. They can have luxury consumption of nitrogen up to a tissue content of a little over 4%. A plant with 4% nitrogen can grow in a nitrogen free environment at a maximum rate with no signs of deficiency until the tissue content has dropped to 1.5%. Then the growth rate will start to drop and nitrogen deficiency symptoms will soon appear.

The critical value for phosphate in stem plants is 0.15% and luxury consumption can go all the way up to 0.7% Thus a fully loaded plant can increase its mass roughly 4.6 times if deprived of phosphate before it hits the critical value of 0.15%.

So, aquarium plants should be able to roughly double their size if nitrogen gets used up, provided that they could load up when nitrogen was available. They should be able to roughly quadruple their size if phosphate drops down to unmeasurable levels, provided they had plenty of phosphorus previously.


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