High CO2's impact on Nitrogen

Tom Barr

Staff member
Jan 23, 2005
That last paper is excellent BTW, this one is good for NO3 uptake at night to resupply the reserved used up during the day into each cell.

Steps towards an integrated view of nitrogen metabolism -- Stitt et al. 53 (370): 959 -- Journal of Experimental Botany

It's a bit easier to read, but there are a lot of good points and ideas here.

Low CO2 Prevents Nitrate Reduction in Leaves -- Kaiser and Förster 91 (3): 970 -- PLANT PHYSIOLOGY

CO2 and NO3 uptake.
Based on that article, what might occur if we do not have any CO2 inb the water in terms of NO3 uptake?

Not much NO3 uptake..........
How about NH4? We do not know, but it does not look promising either.
CO2 declines in our aquariums may reduce/eliminate NH4 uptake dramatically.

Why discuss any of this?

Namely to show strong support for maintaining both good higher levels of NO3 and CO2, and also to address that we cannot have 5-10ppm of NH4 for fish health related issues!

At very low NH4 levels, the NO3 is likely to be assumed to be the dominate player, although plants will use up the NH4 that is there even if very low, the NO3 is still the main driver and source for N when we use CO2.

Non CO2 tanks with very low CO2?
Very well can be NH4 in that case, the plant has less demand for N so that source can easily supply the demand even if a low rate of NH4 loading is present.

But adding NO3 to such tanks does not hurt and in some cases may add to the health of some plants that require more N than others who can rapidly acquire NH4.

In rice:

Cellular compartmentation of ammonium assimilation in rice and barley -- Tobin and Yamaya 52 (356): 591 -- Journal of Experimental Botany

"The major source of nitrogen for developing leaves and ears of mature rice plants is thought to be that released from older, senescing leaves. Evidence for this has come from 15N experiments showing that remobilized nitrogen accounted for 64% of the total nitrogen in the youngest leaf blades (Mae et al., 1981Go). Glutamine, produced during N remobilization, is the major form (as much as 42% of total) of amino acid present in the phloem sap (Hayashi and Chino, 1990Go) and thus the main form of N transported to developing sink tissue, where it is converted to glutamate."

This one is only a few days old, about a week old, fresh off the press:
Assimilation of ammonium ions and reutilization of nitrogen in rice (Oryza sativa L.) -- Tabuchi et al., 10.1093/jxb/erm016 -- Journal of Experimental Botany

Tom Barr