Abstract
Active extracts of nitrate reductase were prepared from the roots of apple seedlings c.v. Granny Smith which were grown in nutrient solution under controlled enviromental conditions. The nutrient solutions contained various ratios of nitrate and ammonium ions but all the treatments contained a total of 112 ppm nitrogen. Maximum nitrate reductase activity in the roots was obtained when plants were supplied with nitrate as the sole source of nitrogen. Roots grown in solution containing only ammonium nitrogen had little or no activity. When plants were supplied with both forms of nitrogen in the nutrient solution, the presence of ammonium ions markedly lowered the activity of nitrate reductase in the roots. Plants supplied with 98 ppm nitrate nitrogen plus 14 ppm ammonium nitrogen had activities only half those of plants grown in nitrate alone. Plants supplied with equal amounts of ammonium and nitrate nitrogen had activities less than one sixth those of plants grown in nitrate alone.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 5
Claim · model-written summary
Nitrate alone gave maximum apple root nitrate reductase activity.
- Taxon
- apple seedlings
Malus domesticat0 - Treatment
- nitrate as the sole source of nitrogene0
- Outcome
- nitrate reductase activity in the rootse0
- Direction
- Maximume0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maximum nitrate reductase activity in the roots was obtained when plants were supplied with nitrate as the sole source of nitrogen”
t0“apple seedlings”
Claim · model-written summary
Ammonium alone yielded little or no root nitrate reductase activity.
- Taxon
- apple seedlingsMalus domesticat0
- Treatment
- only ammonium nitrogene0
- Outcome
- activitye0
- Direction
- little or noe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Roots grown in solution containing only ammonium nitrogen had little or no activity”
t0“apple seedlings”
Claim · model-written summary
Ammonium in mixed nitrogen nutrition markedly lowered apple root nitrate reductase activity.
- Taxon
- apple seedlingsMalus domesticat0
- Treatment
- ammonium ionse0
- Outcome
- activity of nitrate reductase in the rootse0
- Direction
- lowerede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the presence of ammonium ions markedly lowered the activity of nitrate reductase in the roots”
t0“apple seedlings”
Claim · model-written summary
At 98 ppm nitrate plus 14 ppm ammonium, activity was half that under nitrate alone.
- Taxon
- apple seedlingsMalus domesticat0
- Treatment
- 98 ppm nitrate nitrogen plus 14 ppm ammonium nitrogene0
- Outcome
- activitiese0
- Direction
- only halfe0
- Value
- halfe0
- Comparator
- plants grown in nitrate alonee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plants supplied with 98 ppm nitrate nitrogen plus 14 ppm ammonium nitrogen had activities only half those of plants grown in nitrate alone”
t0“apple seedlings”
Claim · model-written summary
Equal ammonium and nitrate produced less than one sixth the activity of nitrate alone.
- Taxon
- apple seedlingsMalus domesticat0
- Treatment
- equal amounts of ammonium and nitrate nitrogene0
- Outcome
- activitiese0
- Direction
- less thane0
- Value
- one sixthe0
- Comparator
- plants grown in nitrate alonee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plants supplied with equal amounts of ammonium and nitrate nitrogen had activities less than one sixth those of plants grown in nitrate alone”
t0“apple seedlings”
The same questions in other papers
nitrogen · physiology: enzyme activity · Malus domestica (apple)Positive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- no effect
- positive
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.