Abstract
ABSTRACT: Interaction effects between nitrogen and UV-B radiation were studied in sunflower (Helianthus annuus L. variety IAC-Iarama) plants grown in a greenhouse under natural photoperiod conditions. Plants were irradiated with 0.8W m-2 (control) or 8.0W m-2 (+UV-B) of UV-B radiation for 7h per day. The plants were grown in pots containing vermiculite and watered with 70% of full strength nitrogen-free Long Ashton solution, containing either low (42.3ppm) or high (282ppm) nitrogen as ammonium nitrate. High nitrogen increased dry matter of stem, leaves and shoot, photosynthetic pigments and photosynthesis (A) without any alteration in stomatal conductance (gs) nor transpiration (E) while it reduced the intercellular CO2 (Ci) concentration, and malondialdehyde (MDA) content. High UV-B radiation had negative effects on dry matter production, A, gs and E with the effects more marked under high nitrogen, whereas it increased Ci under high nitrogen. Activity of PG-POD was reduced by high UV-B radiation under low nitrogen but it was not changed under high nitrogen. The UV-B radiation increased the MDA content independently of nitrogen level. Results indicate that the effects of UV-B radiation on sunflower plants are dependent of nitrogen supply with high nitrogen making their physiological processes more sensitive to UV-B radiation.
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Claims 9
Claim · model-written summary
High nitrogen increased stem, leaf and shoot dry matter.
- Taxon
- sunflower
Helianthus annuuse1 - Treatment
- High nitrogene0
- Outcome
- dry matter of stem, leaves and shoote0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“High nitrogen increased dry matter of stem, leaves and shoot”
e1“sunflower (Helianthus annuus L. variety IAC-Iarama) plants”
Claim · model-written summary
High nitrogen increased pigments and photosynthesis.
- Taxon
- sunflowerHelianthus annuuse1
- Treatment
- High nitrogene0
- Outcome
- photosynthetic pigments and photosynthesis (A)e0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“High nitrogen increased dry matter of stem, leaves and shoot, photosynthetic pigments and photosynthesis (A)”
e1“sunflower (Helianthus annuus L. variety IAC-Iarama) plants”
Claim · model-written summary
High nitrogen left conductance and transpiration unchanged.
- Taxon
- sunflowerHelianthus annuuse1
- Outcome
- stomatal conductance (gs) nor transpiration (E)e0
- Direction
- without any alteratione0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“without any alteration in stomatal conductance (gs) nor transpiration (E)”
e1“sunflower (Helianthus annuus L. variety IAC-Iarama) plants”
Claim · model-written summary
High nitrogen reduced intercellular CO2 and MDA content.
- Taxon
- sunflowerHelianthus annuuse1
- Outcome
- intercellular CO2 (Ci) concentration, and malondialdehyde (MDA) contente0
- Direction
- reducede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“it reduced the intercellular CO2 (Ci) concentration, and malondialdehyde (MDA) content”
e1“sunflower (Helianthus annuus L. variety IAC-Iarama) plants”
Claim · model-written summary
High UV-B harmed dry matter, photosynthesis, conductance and transpiration, especially at high nitrogen.
- Taxon
- sunflowerHelianthus annuuse1
- Treatment
- High UV-B radiatione0
- Outcome
- dry matter production, A, gs and Ee0
- Direction
- negative effectse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“High UV-B radiation had negative effects on dry matter production, A, gs and E with the effects more marked under high nitrogen”
e1“sunflower (Helianthus annuus L. variety IAC-Iarama) plants”
Claim · model-written summary
High UV-B increased intercellular CO2 at high nitrogen.
- Taxon
- sunflowerHelianthus annuuse1
- Outcome
- Cie0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“it increased Ci under high nitrogen”
e1“sunflower (Helianthus annuus L. variety IAC-Iarama) plants”
Claim · model-written summary
High UV-B reduced PG-POD under low nitrogen.
- Taxon
- sunflowerHelianthus annuuse1
- Treatment
- high UV-B radiatione0
- Outcome
- Activity of PG-PODe0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Activity of PG-POD was reduced by high UV-B radiation under low nitrogen”
e1“sunflower (Helianthus annuus L. variety IAC-Iarama) plants”
Claim · model-written summary
PG-POD was unchanged under high nitrogen.
- Taxon
- sunflowerHelianthus annuuse1
- Outcome
- ite0
- Direction
- not changede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“it was not changed under high nitrogen”
e1“sunflower (Helianthus annuus L. variety IAC-Iarama) plants”
Claim · model-written summary
UV-B increased MDA regardless of nitrogen.
- Taxon
- sunflowerHelianthus annuuse1
- Treatment
- UV-B radiatione0
- Outcome
- MDA contente0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The UV-B radiation increased the MDA content independently of nitrogen level”
e1“sunflower (Helianthus annuus L. variety IAC-Iarama) plants”
The same questions in other papers
nitrogen · growth · Helianthus annuus (common sunflower)Results differ
62 papers in the same direction as this paper · 12 in the opposite direction · 1 reporting no difference from an alternative
- no effect
- negative
- negative
72 papers more in this group
See all 76 papers →nitrogen · physiology: photosynthesis · Helianthus annuus (common sunflower)Positive and negative results
9 papers in the same direction as this paper · 2 in the opposite direction
- no effect
- negative
- positive
8 papers more in this group
See all 12 papers →uv · physiology: gas exchange · Helianthus annuus (common sunflower)Results agree
2 papers in the same direction as this paper
- no effect
- no effect
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.