Abstract
The morphological and physiological adaptation of Lactuca sativa L. (‘Vegas’) to different irradiance levels and rates of nitrogen supply was analysed in such a way that effects of irradiance were clearly distinguished from the effects of nitrogen. Lettuce was grown in a glasshouse in aerated nutrient solutions containing all necessary nutrients except nitrogen. Nitrogen was supplied in excess and at limiting rates in relation to plant growth to provide steady state nutrition. Shading the plants created the low irradiance level. The effects of nitrogen supply and irradiance on growth showed a marked interaction. Dry matter production decreased strongly with decreasing nitrogen supply at high irradiance, but decreased only slightly at low irradiance. Nitrogen had no effect on radiation use efficiency except for the lowest nitrogen treatment at high irradiance. The effect of nitrogen on growth was mainly mediated by its effect on leaf area development and hence on light interception. Decreases in leaf area were due to decreases in specific leaf area and dry matter partitioning towards the leaves, while the decrease in specific leaf area was the result of an increase in leaf dry matter percentage at low nitrogen supply. Dry matter and nitrogen partitioning, and nitrate concentration were closely related to plant nitrogen concentration. Irradiance did not affect these relationships. Irradiance influenced partitioning only indirectly by affecting plant nitrogen concentration. The demand for organic nitrogen per unit leaf area was lower at lower irradiance. Organic nitrogen per unit leaf area appeared to be adjusted to the irradiance level, independently of the nitrogen supply, suggesting priority of nitrogen usage in photosynthesis. Copyright 2000 Annals of Botany Company
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 12
Claim · model-written summary
Nitrogen supply and irradiance interacted in effects on growth.
Not reportedTaxonDirection
Verbatim
e0“The effects of nitrogen supply and irradiance on growth showed a marked interaction.”
Claim · model-written summary
Lower nitrogen reduced dry matter production strongly at high irradiance.
- Taxon
- Lactuca sativa L.
Lactuca sativat0 - Treatment
- decreasing nitrogen supplye0
- Outcome
- Dry matter productione0
- Direction
- decreased stronglye0
- Qualifier
- high irradiancee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Dry matter production decreased strongly with decreasing nitrogen supply at high irradiance”
t0“Lactuca sativa L.”
Claim · model-written summary
Lower nitrogen reduced dry matter production only slightly at low irradiance.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Direction
- decreased only slightlye0
- Qualifier
- low irradiancee0
Not reportedTreatmentComparatorOutcome
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“but decreased only slightly at low irradiance.”
t0“Lactuca sativa L.”
Claim · model-written summary
Nitrogen had no effect on radiation use efficiency except at the lowest treatment under high irradiance.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Treatment
- Nitrogene0
- Outcome
- radiation use efficiencye0
- Direction
- no effecte0
- Qualifier
- except for the lowest nitrogen treatment at high irradiancee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen had no effect on radiation use efficiency except for the lowest nitrogen treatment at high irradiance.”
t0“Lactuca sativa L.”
Claim · model-written summary
Nitrogen affected growth mainly through leaf area development and light interception.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Treatment
- nitrogene0
- Outcome
- growthe0
- Qualifier
- leaf area development and hence on light interceptione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The effect of nitrogen on growth was mainly mediated by its effect on leaf area development and hence on light interception.”
t0“Lactuca sativa L.”
Claim · model-written summary
Reduced specific leaf area and partitioning to leaves explained reduced leaf area.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Outcome
- leaf areae0
- Qualifier
- decreases in specific leaf area and dry matter partitioning towards the leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Decreases in leaf area were due to decreases in specific leaf area and dry matter partitioning towards the leaves”
t0“Lactuca sativa L.”
Claim · model-written summary
Higher leaf dry matter percentage at low nitrogen explained lower specific leaf area.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Treatment
- low nitrogen supplye0
- Outcome
- specific leaf areae0
- Qualifier
- increase in leaf dry matter percentagee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the decrease in specific leaf area was the result of an increase in leaf dry matter percentage at low nitrogen supply.”
t0“Lactuca sativa L.”
Claim · model-written summary
Dry matter and nitrogen partitioning and nitrate concentration were closely related to plant nitrogen concentration.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Outcome
- Dry matter and nitrogen partitioning, and nitrate concentratione0
- Qualifier
- plant nitrogen concentratione0
Not reportedTreatmentDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Dry matter and nitrogen partitioning, and nitrate concentration were closely related to plant nitrogen concentration.”
t0“Lactuca sativa L.”
Claim · model-written summary
Irradiance did not affect these nitrogen concentration relationships.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Treatment
- Irradiancee0
- Outcome
- these relationshipse0
- Direction
- did not affecte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Irradiance did not affect these relationships.”
t0“Lactuca sativa L.”
Claim · model-written summary
Irradiance influenced partitioning indirectly through plant nitrogen concentration.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Treatment
- Irradiancee0
- Outcome
- partitioninge0
- Qualifier
- affecting plant nitrogen concentratione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Irradiance influenced partitioning only indirectly by affecting plant nitrogen concentration.”
t0“Lactuca sativa L.”
Claim · model-written summary
Demand for organic nitrogen per unit leaf area was lower at lower irradiance.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Treatment
- lower irradiancee0
- Outcome
- demand for organic nitrogen per unit leaf areae0
- Direction
- lowere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The demand for organic nitrogen per unit leaf area was lower at lower irradiance.”
t0“Lactuca sativa L.”
Claim · model-written summary
Organic nitrogen per leaf area adjusted to irradiance independently of nitrogen supply, suggesting priority for photosynthesis.
- Taxon
- Lactuca sativa L.Lactuca sativat0
- Treatment
- irradiance levele0
- Outcome
- Organic nitrogen per unit leaf areae0
- Qualifier
- priority of nitrogen usage in photosynthesise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Organic nitrogen per unit leaf area appeared to be adjusted to the irradiance level, independently of the nitrogen supply, suggesting priority of nitrogen usage in photosynthesis.”
t0“Lactuca sativa L.”
The same questions in other papers
nitrogen · growth · Lactuca sativa (garden lettuce)Results differ
24 papers in the same direction as this paper · 60 in the opposite direction
- positive
- positive
- positive
81 papers more in this group
See all 85 papers →nitrogen · yield · Lactuca sativa (garden lettuce)Positive and negative results
60 papers in the same direction as this paper · 17 in the opposite direction · 1 reporting no difference from an alternative
This paper is about lacking the nutrient, so it counts the other way round here.
- no effect
- positive
- positive
75 papers more in this group
See all 79 papers →light · growth · Lactuca sativa (garden lettuce)Positive and negative results
56 papers in the same direction as this paper · 243 in the opposite direction
- positive
- positive
- positive
296 papers more in this group
See all 300 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.