Abstract
ABSTRACT Projected depletions in the stratospheric ozone layer will result in increases in solar ultraviolet‐B radiation (290–320 nm) reaching the earth's surface, These increases will likely occur in concert with other environmental changes such as increases in atmospheric carbon dioxide concentrations. Currently very little information is available on the effectiveness of UV‐B radiation within a CO 2 ‐enriched atmosphere, and this is especially true for trees. Loblolly pine ( Pinus taeda L.) seedlings were grown in a factorial experiment at the Duke University Phytotron with either 0, 8.8 or 13.8 kJ m −2 of biologically effective UV‐B radiation (UV‐B BE ). The CO 2 concentrations used were 350 and 650 μmol mol −1 . Measurements of chlorophyll fluorescence were made at 5‐week intervals and photosynthetic oxygen evolution and leaf pigments were measured after 22 weeks, prior to harvest. The results of this study demonstrated a clear growth response to CO 2 enrichment but neither photosynthetic capacity nor quantum efficiency were altered by CO 2 . The higher UV‐B irradiance reduced total biomass by about 12% at both CO 2 levels but biomass partitioning was altered by the interaction of CO 2 and UV‐B radiation. Dry matter was preferentially allocated to shoot components by UV‐B radiation at 350 μmol mol −1 CO 2 and towards root components at 650 μmol mol −1 CO 2 . These subtle effects on biomass allocation could be important in the future to seedling establishment and competitive interactions in natural as well as agricultural communities.
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Claims 6
Claim · model-written summary
CO2 enrichment produced a clear growth response in loblolly pine seedlings.
- Taxon
- Loblolly pine
Pinus taedae0 - Treatment
- CO 2 enrichmente2
- Outcome
- growth responsee2
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Loblolly pine ( Pinus taeda L.) seedlings were grown in a factorial experiment”
e2“The results of this study demonstrated a clear growth response to CO 2 enrichment but neither photosynthetic capacity nor quantum efficiency were altered by CO 2”
Claim · model-written summary
CO2 enrichment did not alter photosynthetic capacity or quantum efficiency of loblolly pine seedlings.
- Taxon
- Loblolly pinePinus taedae0
- Treatment
- CO 2 enrichmente2
- Outcome
- photosynthetic capacity nor quantum efficiencye2
- Direction
- alterede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Loblolly pine ( Pinus taeda L.) seedlings were grown in a factorial experiment”
e2“The results of this study demonstrated a clear growth response to CO 2 enrichment but neither photosynthetic capacity nor quantum efficiency were altered by CO 2”
Claim · model-written summary
Higher UV-B irradiance reduced total biomass of loblolly pine by about 12% at both CO2 levels.
- Taxon
- Loblolly pinePinus taedae0
- Treatment
- higher UV‐B irradiancee3
- Outcome
- total biomasse3
- Direction
- reducede3
- Value
- 12%e3
- Qualifier
- at both CO 2 levelse3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Loblolly pine ( Pinus taeda L.) seedlings were grown in a factorial experiment”
e3“The higher UV‐B irradiance reduced total biomass by about 12% at both CO 2 levels”
Claim · model-written summary
The interaction of CO2 and UV-B radiation alters biomass partitioning in loblolly pine.
- Taxon
- Loblolly pinePinus taedae0
- Treatment
- interaction of CO 2 and UV‐B radiatione5
- Outcome
- biomass partitioninge5
- Direction
- alterede5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Loblolly pine ( Pinus taeda L.) seedlings were grown in a factorial experiment”
e5“biomass partitioning was altered by the interaction of CO 2 and UV‐B radiation”
Claim · model-written summary
UV-B radiation at 350 μmol mol −1 CO2 preferentially allocated dry matter to shoot components of loblolly pine.
- Taxon
- Loblolly pinePinus taedae0
- Treatment
- UV‐B radiatione4
- Outcome
- shoot componentse4
- Direction
- preferentially allocatede4
- Qualifier
- at 350 μmol mol −1 CO 2e4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Loblolly pine ( Pinus taeda L.) seedlings were grown in a factorial experiment”
e4“Dry matter was preferentially allocated to shoot components by UV‐B radiation at 350 μmol mol −1 CO 2 and towards root components at 650 μmol mol −1 CO 2”
Claim · model-written summary
UV-B radiation at 650 μmol mol −1 CO2 directed dry matter towards root components of loblolly pine.
- Taxon
- Loblolly pinePinus taedae0
- Treatment
- UV‐B radiatione4
- Outcome
- root componentse4
- Direction
- towardse4
- Qualifier
- at 650 μmol mol −1 CO 2e4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Loblolly pine ( Pinus taeda L.) seedlings were grown in a factorial experiment”
e4“Dry matter was preferentially allocated to shoot components by UV‐B radiation at 350 μmol mol −1 CO 2 and towards root components at 650 μmol mol −1 CO 2”
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See all 7 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.