Abstract
Abstract Nitrogen (N) is one of the most critical elements affecting grass seed yield. In soil and cropping conditions of Western Oregon, ammonium‐N may play an important role in the growth and development of ryegrass grown for seed. Our objectives were to determine the physiological and biochemical effects of ammonium and nitrate nutrition on ryegrass vegetative growth and subsequent expression of floral tillers, and changes in plant reduced‐N and carbohydrate composition. Plants were grown in hydroponics (active pH‐controlled) and fed nitrate and ammonium alone or in combination at 10 mM total N. The experiment was terminated at anthesis, which occurred at 68 days after planting (DAP). Changes in plant tiller number, height, dry weight, reduced‐N, and water‐soluble carbohydrates (WSC) were recorded. Vegetative growth rate of plants receiving lower ratios of nitrate/ammonium was up to twice those receiving total nitrate or 75/25 nitrate/ammonium. Total primary tiller number at 68 DAP (anthesis) was 30% greater in plants receiving 25/75 and 0/100 nitrate/ammonium. Floral tiller number increased up to 55% with increasing ammonium‐N to nitrate‐N, while vegetative tiller number was not significantly affected. Partitioning of dry matter, WSC, and reduced‐N among vegetative and reproductive organs differed among N treatments. Data indicated that differences in plant growth and development resulted from greater N use efficiency from mixtures of ammonium and nitrate nutrition. Data support previous reports of ryegrass preference for ammonium nutrition over nitrate.
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Claims 10
Claim · model-written summary
Lower nitrate to ammonium ratios gave ryegrass up to twice the vegetative growth rate of total nitrate or 75/25 feeding.
- Treatment
- lower ratios of nitrate/ammoniume0
- Outcome
- Vegetative growth ratee0
- Direction
- up to twicee0
- Value
- up to twicee0
- Comparator
- total nitrate or 75/25 nitrate/ammoniume0
LoliumOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Vegetative growth rate of plants receiving lower ratios of nitrate/ammonium was up to twice those receiving total nitrate or 75/25 nitrate/ammonium”
t0“ryegrass”
Claim · model-written summary
At anthesis, primary tiller number was 30% greater under 25/75 nitrate/ammonium.
- Organ / stage
- anthesise0
- Treatment
- 25/75e0
- Outcome
- Total primary tiller numbere0
- Direction
- greatere0
- Value
- 30%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total primary tiller number at 68 DAP (anthesis) was 30% greater in plants receiving 25/75 and 0/100 nitrate/ammonium”
t0“ryegrass”
Claim · model-written summary
At anthesis, primary tiller number was 30% greater under 0/100 nitrate/ammonium.
- Organ / stage
- anthesise0
- Treatment
- 0/100 nitrate/ammoniume0
- Outcome
- Total primary tiller numbere0
- Direction
- greatere0
- Value
- 30%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total primary tiller number at 68 DAP (anthesis) was 30% greater in plants receiving 25/75 and 0/100 nitrate/ammonium”
t0“ryegrass”
Claim · model-written summary
Increasing ammonium relative to nitrate increased floral tiller number by up to 55%.
- Treatment
- increasing ammonium‐N to nitrate‐Ne0
- Outcome
- Floral tiller numbere0
- Direction
- increasede0
- Value
- 55%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Floral tiller number increased up to 55% with increasing ammonium‐N to nitrate‐N”
t0“ryegrass”
Claim · model-written summary
Ammonium to nitrate balance did not significantly affect vegetative tiller number.
- Outcome
- vegetative tiller numbere0
Not reportedTreatmentComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“vegetative tiller number was not significantly affected”
t0“ryegrass”
Claim · model-written summary
Nitrogen treatment changed dry matter allocation among vegetative and reproductive organs.
- Organ / stage
- vegetative and reproductive organse0
- Treatment
- N treatmentse0
- Outcome
- Partitioning of dry mattere0
- Direction
- differede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Partitioning of dry matter, WSC, and reduced‐N among vegetative and reproductive organs differed among N treatments”
t0“ryegrass”
Claim · model-written summary
Nitrogen treatment changed water-soluble carbohydrate allocation among vegetative and reproductive organs.
- Organ / stage
- vegetative and reproductive organse0
- Treatment
- N treatmentse0
- Outcome
- WSCe0
- Direction
- differede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Partitioning of dry matter, WSC, and reduced‐N among vegetative and reproductive organs differed among N treatments”
t0“ryegrass”
Claim · model-written summary
Nitrogen treatment changed reduced nitrogen allocation among vegetative and reproductive organs.
- Organ / stage
- vegetative and reproductive organse0
- Treatment
- N treatmentse0
- Outcome
- reduced‐Ne0
- Direction
- differede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Partitioning of dry matter, WSC, and reduced‐N among vegetative and reproductive organs differed among N treatments”
t0“ryegrass”
Claim · model-written summary
The authors attribute growth and developmental differences to greater nitrogen use efficiency from mixed ammonium and nitrate.
- Treatment
- mixtures of ammonium and nitrate nutritione0
- Outcome
- differences in plant growth and developmente0
- Qualifier
- greater N use efficiencye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“differences in plant growth and development resulted from greater N use efficiency from mixtures of ammonium and nitrate nutrition”
t0“ryegrass”
Claim · model-written summary
The data support a ryegrass preference for ammonium nutrition over nitrate.
- Outcome
- preference for ammonium nutrition over nitratee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Data support previous reports of ryegrass preference for ammonium nutrition over nitrate”
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See all 54 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.