Abstract
Morgan, M. A. and Jackson, W. A. 1988. Inward and outward movement of ammonium in root systems: transient responses during recovery from nitrogen deprivation in presence of ammonium.— J. exp. Bot. 39: 179-191. Net ammonium uptake by 20-d-old wheat (Triticum aestivum cv. Kleiber) and oat (Avena sativa cv. Tarok) seedlings was increased 5- to 10-fold when the seedlings were deprived of nitrate during the 14-20 d period. The effect of nitrogen deprivation was to increase net 15N-ammonium influx and decrease net 14N-ammonium efflux during a 1 h assay period. The sizeable rate of net 15N-ammonium influx resulting from nitrogen deprivation was stimulated further by prior exposure of the seedlings to 14N-ammonium for 5 h. Additional exposure to 14N-ammonium caused the stimulated rate of 15N-ammonium influx to decline. During the 1 h assays in 15N-ammonium, net 14N-ammonium efflux increased after 2 h exposure to 14N-ammonium, peaked at 5–10 h, and then declined. The consequence of the differential response of the influx and efflux processes in wheat was a marked decrease in net ammonium uptake in the initial 2–5 h, followed by a recovery which, in turn, was followed by a slow decline. In oat, there was no recovery in net ammonium uptake after 2–5 h. Interference in ammonium assimilation by presence of methionine sulphoximine after 5 h did not inhibit expression of the ammonium-stimulated net 15N-ammonium influx at 10 h but did substantially increase net 14N-ammonium efflux. In nitrogen depleted seedlings, and in those exposed to 14N-ammonium for 2 h, subsequent net 14N-ammonium efflux during 1 h in 15N-ammonium exceeded the quantity of 14N-ammonium initially in the roots. The increase in 15N-ammonium influx upon nitrogen deprivation, its further stimulation with 5-10 h exposure to ammonium and its subsequent decline, are discussed as possibly resulting from (a) the operation of two ammonium influx systems (b) the interplay of tissue ammonium and a product of its assimilation respectively acting as positive and negative effectors of a single influx system and (c) variations in energy supply from the shoots.
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Claims 4
Claim · model-written summary
Nitrate deprivation increased net ammonium uptake in wheat seedlings five to tenfold.
- Taxon
- wheat
Triticum aestivume0 - Material
- Triticum aestivum cv. Kleibere0
- Treatment
- deprived of nitratee0
- Outcome
- Net ammonium uptakee0
- Direction
- increasede0
- Value
- 5- to 10-folde0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Net ammonium uptake by 20-d-old wheat (Triticum aestivum cv. Kleiber) and oat (Avena sativa cv. Tarok) seedlings was increased 5- to 10-fold when the seedlings were deprived of nitrate during the 14-20 d period.”
Claim · model-written summary
Nitrate deprivation increased net ammonium uptake in oat seedlings five to tenfold.
- Taxon
- oat
Avena sativae0 - Material
- Avena sativa cv. Taroke0
- Treatment
- deprived of nitratee0
- Outcome
- Net ammonium uptakee0
- Direction
- increasede0
- Value
- 5- to 10-folde0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Net ammonium uptake by 20-d-old wheat (Triticum aestivum cv. Kleiber) and oat (Avena sativa cv. Tarok) seedlings was increased 5- to 10-fold when the seedlings were deprived of nitrate during the 14-20 d period.”
Claim · model-written summary
Wheat net uptake fell initially, recovered, then slowly declined.
- Taxon
- wheatTriticum aestivume0
- Outcome
- net ammonium uptakee0
- Direction
- marked decreasee0
- Qualifier
- followed by a recovery which, in turn, was followed by a slow declinee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in wheat was a marked decrease in net ammonium uptake in the initial 2–5 h, followed by a recovery which, in turn, was followed by a slow decline.”
Claim · model-written summary
Oat net ammonium uptake did not recover after two to five hours.
- Taxon
- oatAvena sativae0
- Outcome
- net ammonium uptakee0
- Direction
- no recoverye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In oat, there was no recovery in net ammonium uptake after 2–5 h.”
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See all 479 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.