Abstract
Nitrogen nutrition strongly affected the growth rate of young sunflower (Helianthus annuus L.) leaves. When plants were grown from seed on either of two levels of N availability, a 33% decrease in tissue N of expanding leaves was associated with a 75% overall inhibition of leaf growth. Almost all of the growth inhibition resulted from a depression of the daytime growth rate. Measurements of pressure-induced water flux through roots showed that N deficiency decreased root hydraulic conductivity by about half. Thus, N deficiency lowered the steady-state water potential of expanding leaves during the daytime when transpiration was occurring. As a result, N-deficient leaves were unable to maintain adequate turgor for growth in the daytime. N deficiency also decreased the hydraulic conductivity for water movement into expanding leaf cells in the absence of transpiration, but growth inhibition at night was much less than in the daytime. N nutrition had no detectable effects on plastic extensibility or the threshold turgor for growth.
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Claims 9
Claim · model-written summary
A 33% decline in leaf tissue nitrogen accompanied 75% inhibition of leaf growth.
- Taxon
- sunflower (Helianthus annuus L.)
Helianthus annuust0 - Organ / stage
- expanding leavese0
- Compound
- tissue Ne0
- Outcome
- overall inhibition of leaf growthe0
- Value
- 75%e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a 33% decrease in tissue N of expanding leaves was associated with a 75% overall inhibition of leaf growth”
t0“young sunflower (Helianthus annuus L.) leaves”
Claim · model-written summary
Almost all growth inhibition came from reduced daytime growth.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuust0
- Outcome
- growth inhibitione0
- Qualifier
- depression of the daytime growth ratee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Almost all of the growth inhibition resulted from a depression of the daytime growth rate”
t0“young sunflower (Helianthus annuus L.) leaves”
Claim · model-written summary
Nitrogen deficiency halved root hydraulic conductivity.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuust0
- Treatment
- N deficiencye0
- Outcome
- root hydraulic conductivitye0
- Direction
- decreasede0
- Value
- about halfe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N deficiency decreased root hydraulic conductivity by about half”
t0“young sunflower (Helianthus annuus L.) leaves”
Claim · model-written summary
Nitrogen deficiency lowered daytime expanding-leaf water potential.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuust0
- Treatment
- N deficiencye0
- Outcome
- steady-state water potential of expanding leavese0
- Direction
- lowerede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N deficiency lowered the steady-state water potential of expanding leaves during the daytime when transpiration was occurring”
t0“young sunflower (Helianthus annuus L.) leaves”
Claim · model-written summary
Nitrogen-deficient leaves could not maintain sufficient daytime turgor for growth.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuust0
- Outcome
- adequate turgor for growthe0
- Qualifier
- in the daytimee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N-deficient leaves were unable to maintain adequate turgor for growth in the daytime”
t0“young sunflower (Helianthus annuus L.) leaves”
Claim · model-written summary
Nitrogen deficiency reduced hydraulic conductivity into expanding leaf cells without transpiration.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuust0
- Treatment
- N deficiencye0
- Outcome
- hydraulic conductivity for water movement into expanding leaf cellse0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N deficiency also decreased the hydraulic conductivity for water movement into expanding leaf cells in the absence of transpiration”
t0“young sunflower (Helianthus annuus L.) leaves”
Claim · model-written summary
Nighttime growth inhibition was much less than daytime inhibition.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuust0
- Outcome
- growth inhibition at nighte0
- Direction
- much lesse0
- Comparator
- in the daytimee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“growth inhibition at night was much less than in the daytime”
t0“young sunflower (Helianthus annuus L.) leaves”
Claim · model-written summary
Nitrogen nutrition had no detectable effect on plastic extensibility.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuust0
- Treatment
- N nutritione0
- Outcome
- plastic extensibilitye0
- Direction
- no detectable effectse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N nutrition had no detectable effects on plastic extensibility or the threshold turgor for growth”
t0“young sunflower (Helianthus annuus L.) leaves”
Claim · model-written summary
Nitrogen nutrition had no detectable effect on threshold turgor for growth.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuust0
- Treatment
- N nutritione0
- Outcome
- threshold turgor for growthe0
- Direction
- no detectable effectse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N nutrition had no detectable effects on plastic extensibility or the threshold turgor for growth”
t0“young sunflower (Helianthus annuus L.) leaves”
The same questions in other papers
nitrogen · physiology: water · Helianthus annuus (common sunflower)Positive and negative results
4 papers in the same direction as this paper · 4 in the opposite direction
This paper is about lacking the nutrient, so it counts the other way round here.
- no effect
- no effect
- negative
5 papers more in this group
See all 9 papers →nitrogen · soil: physics · Helianthus annuus (common sunflower)Results agree
2 papers in the same direction as this paper
This paper is about lacking the nutrient, so it counts the other way round here.
- positive
- 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.