Abstract
To compare the effects of supplementary ultraviolet-B (UV-B) radiation on a tropical/subtropical and a temperate plant, two indica rice cultivars (Er Bai Ai and Lemont) and peas were exposed to supplementary UV-B radiation for 8 days (biologically effective irradiance of 0.68 W m-2, 12 h per day). Marked decreases occurred in the ratios of variable to maximum chlorophyll fluorescence yield and in the quantum yield of photosynthetic oxygen evolution over the 8 day treatment period. The greatest decline always occurred in pea leaves, while in rice, cv. Er Bai Ai was more susceptible to UV-B radiation than cv. Lemont. Compared with control plants, the content of soluble protein and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) protein decreased significantly after the UV-B treatment; the greatest decrease occurred in pea leaves, while the rate of decrease in rice was greater in cv. Er Bai Ai than cv. Lemont. Over the 8 day UV-B treatment period, the increase of UV-B-absorbing compounds was greater in rice leaves than in pea leaves, and greater in cv. Er Bai Ai than in cv. Lemont, although cv. Lemont was more UV-B tolerant. We suggest that the increase in these compounds is not the only indicator of resistance to UV-B damage; other factors, yet to be identified, may also confer UV-B tolerance. While leaf orientation may be related to the severity of UV-B damage, naturally near-horizontal pea leaves were still much more susceptible to UV-B damage compared with rice leaves which were held horizontally over the 8 day treatment period. Brown spots appeared on the upper surface of leaves of cv. Er Bai Ai after 2 days of UV-B treatment and showed a cumulative increase with the duration of exposure. Our study confirms the multiplicity of photosynthetic responses and of different protective strategies that may account for the differential sensitivity of plants to supplementary UV-B radiation.
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Claims 12
Claim · model-written summary
UV-B reduced variable-to-maximum chlorophyll fluorescence yield ratios in rice and pea.
- Taxon
- Rice and Pea Plants
Lathyrus oleraceus
Oryza sativat0 - Treatment
- supplementary UV-B radiatione1
- Outcome
- ratios of variable to maximum chlorophyll fluorescence yielde0
- Direction
- decreasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice and Pea Plants”
e0“Marked decreases occurred in the ratios of variable to maximum chlorophyll fluorescence yield and in the quantum yield of photosynthetic oxygen evolution over the 8 day treatment period”
e1“exposed to supplementary UV-B radiation for 8 days”
Claim · model-written summary
UV-B reduced quantum yield of photosynthetic oxygen evolution in rice and pea.
- Taxon
- Rice and Pea PlantsLathyrus oleraceusOryza sativat0
- Treatment
- supplementary UV-B radiatione1
- Outcome
- quantum yield of photosynthetic oxygen evolutione0
- Direction
- decreasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice and Pea Plants”
e0“Marked decreases occurred in the ratios of variable to maximum chlorophyll fluorescence yield and in the quantum yield of photosynthetic oxygen evolution over the 8 day treatment period”
e1“exposed to supplementary UV-B radiation for 8 days”
Claim · model-written summary
The fluorescence and oxygen-evolution decline was greatest in pea leaves.
- Taxon
- PeaLathyrus oleraceust0
- Organ / stage
- pea leavese0
- Outcome
- declinee0
- Direction
- greateste0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Pea Plants”
e0“The greatest decline always occurred in pea leaves, while in rice, cv. Er Bai Ai was more susceptible to UV-B radiation than cv. Lemont”
Claim · model-written summary
Rice cultivar Er Bai Ai was more susceptible to UV-B than Lemont.
- Taxon
- RiceOryza sativat0
- Material
- Er Bai Aie0
- Outcome
- susceptible to UV-B radiatione0
- Direction
- more susceptiblee0
- Comparator
- Lemonte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice”
e0“cv. Er Bai Ai was more susceptible to UV-B radiation than cv. Lemont”
Claim · model-written summary
UV-B significantly decreased soluble protein content relative to control plants.
- Taxon
- Rice and Pea PlantsLathyrus oleraceusOryza sativat0
- Treatment
- UV-B treatmente0
- Outcome
- content of soluble proteine0
- Direction
- decreasede0
- Comparator
- control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice and Pea Plants”
e0“Compared with control plants, the content of soluble protein and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) protein decreased significantly after the UV-B treatment”
Claim · model-written summary
UV-B significantly decreased Rubisco protein content relative to controls.
- Taxon
- Rice and Pea PlantsLathyrus oleraceusOryza sativat0
- Treatment
- UV-B treatmente0
- Gene
- ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco)e0
- Outcome
- ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) proteine0
- Direction
- decreasede0
- Comparator
- control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice and Pea Plants”
e0“Compared with control plants, the content of soluble protein and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) protein decreased significantly after the UV-B treatment”
Claim · model-written summary
Protein decline was greatest in pea leaves and greater in Er Bai Ai than Lemont rice.
- Taxon
- Rice and Pea PlantsLathyrus oleraceusOryza sativat0
- Outcome
- rate of decreasee0
- Direction
- greatere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice and Pea Plants”
e0“the greatest decrease occurred in pea leaves, while the rate of decrease in rice was greater in cv. Er Bai Ai than cv. Lemont”
Claim · model-written summary
UV-B absorbing compounds increased more in rice leaves than pea leaves.
- Taxon
- RiceOryza sativat0
- Organ / stage
- rice leavese0
- Treatment
- supplementary UV-B radiatione1
- Outcome
- UV-B-absorbing compoundse0
- Direction
- greatere0
- Comparator
- pea leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the increase of UV-B-absorbing compounds was greater in rice leaves than in pea leaves”
e1“exposed to supplementary UV-B radiation for 8 days”
t0“Rice”
Claim · model-written summary
UV-B absorbing compounds increased more in Er Bai Ai than Lemont rice.
- Taxon
- RiceOryza sativat0
- Material
- cv. Er Bai Aie0
- Outcome
- UV-B-absorbing compoundse1
- Direction
- greatere0
- Comparator
- cv. Lemonte0
Not reportedTreatment
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice”
e0“greater in cv. Er Bai Ai than in cv. Lemont, although cv. Lemont was more UV-B tolerant”
e1“the increase of UV-B-absorbing compounds”
Claim · model-written summary
The authors infer that absorbing compound increases alone do not indicate UV-B resistance.
- Taxon
- Rice and Pea PlantsLathyrus oleraceusOryza sativat0
- Outcome
- resistance to UV-B damagee0
- Qualifier
- other factors, yet to be identifiede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice and Pea Plants”
e0“the increase in these compounds is not the only indicator of resistance to UV-B damage; other factors, yet to be identified, may also confer UV-B tolerance”
Claim · model-written summary
Pea leaves were more susceptible to UV-B damage than horizontally held rice leaves.
- Taxon
- PeaLathyrus oleraceust0
- Organ / stage
- pea leavese0
- Outcome
- susceptible to UV-B damagee0
- Direction
- much more susceptiblee0
- Comparator
- rice leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Pea Plants”
e0“naturally near-horizontal pea leaves were still much more susceptible to UV-B damage compared with rice leaves which were held horizontally over the 8 day treatment period”
Claim · model-written summary
Brown spots appeared on Er Bai Ai leaves after two days of UV-B and accumulated with exposure duration.
- Taxon
- RiceOryza sativat0
- Material
- cv. Er Bai Aie0
- Organ / stage
- leavese0
- Outcome
- Brown spotse0
- Direction
- cumulative increasee0
- Qualifier
- after 2 days of UV-B treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice”
e0“Brown spots appeared on the upper surface of leaves of cv. Er Bai Ai after 2 days of UV-B treatment and showed a cumulative increase with the duration of exposure”
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See all 6 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.