Abstract
The impact of elevated ultraviolet‐B radiation (UV‐B, 280–320 nm) on membrane systems and lipid peroxidation, and possible involvement of active oxygen radicals was investigated in leaves of two UV‐B susceptible rice cultivars ( Oryza sativa L. cvs IR74 and Dular). Rice seedlings were grown in a greenhouse for 10 days and then treated with biologically effective UV‐B (UV‐B BE ) radiation for 28 days. Oxidative stress effects were evaluated by measuring superoxide anion (O 2 ) generation rate, hydrogen peroxide (H 2 O 2 ) content, malondialdehyde (MDA) concentration and relative electrolyte conductivity (EC) for IR74 and Dular at 0 (control), 6 or 13 kJ m −2 day −1 UV‐B BE . Significant increases in these parameters were found in rice plants grown at 13 vs 0 kJ m −2 day −1 UV‐B BE after 28 days; indicating that disruption of membrane systems may be an eventual reason for UV‐B‐induced injury in rice plants. There was a positive correlation between O 2 − generation and increases in EC or MDA in leaves. Activities of enzymatic and nonenzymatic free radical scavengers were measured for IR74 after 7, 14, 21 and 28 days of exposure to 13 or 0 UV‐B BE to evaluate dynamics of these responses over time. Activities of catalase and superoxide dismutase (but not ascorbate peroxidase) and concentrations of ascorbic acid and glutathione were enhanced by 13 vs 0 UV‐B BE after 14 days of UV‐B exposure. Further exposure to 28 days of UV‐B was associated with a decline in enzyme activities and ascorbic acid, but not glutathione. It is suggested that UV‐B‐induced injury may be associated with disturbance of active oxygen metabolism through the destruction and alteration of both enzymatic and nonenzymatic defense systems in rice.
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Claims 10
Claim · model-written summary
Supplemental UV-B at 13 kJ m-2 day-1 increased superoxide anion generation, hydrogen peroxide content and MDA concentration in rice leaves after 28 days
- Taxon
- rice (Oryza sativa)
Oryza sativat0 - Treatment
- 13 kJ m −2 day −1 UV‐B BEe2
- Outcome
- superoxide anion (O 2 ) generation rate, hydrogen peroxide (H 2 O 2 ) content, malondialdehyde (MDA) concentratione2
- Direction
- increasese1
- Qualifier
- after 28 dayse1
- Comparator
- 0 (control)e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“in rice (Oryza sativa) leaves”
e1“Significant increases in these parameters were found in rice plants grown at 13 vs 0 kJ m −2 day −1 UV‐B BE after 28 days”
e2“Oxidative stress effects were evaluated by measuring superoxide anion (O 2 ) generation rate, hydrogen peroxide (H 2 O 2 ) content, malondialdehyde (MDA) concentration and relative electrolyte conductivity (EC) for IR74 and Dular at 0 (control), 6 or 13 kJ m −2 day −1 UV‐B BE”
Claim · model-written summary
Supplemental UV-B at 13 kJ m-2 day-1 increased relative electrolyte conductivity in rice leaves after 28 days
- Taxon
- rice (Oryza sativa)Oryza sativat0
- Treatment
- 13 kJ m −2 day −1 UV‐B BEe2
- Outcome
- relative electrolyte conductivity (EC)e2
- Direction
- increasese1
- Qualifier
- after 28 dayse1
- Comparator
- 0 (control)e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“in rice (Oryza sativa) leaves”
e1“Significant increases in these parameters were found in rice plants grown at 13 vs 0 kJ m −2 day −1 UV‐B BE after 28 days”
e2“Oxidative stress effects were evaluated by measuring superoxide anion (O 2 ) generation rate, hydrogen peroxide (H 2 O 2 ) content, malondialdehyde (MDA) concentration and relative electrolyte conductivity (EC) for IR74 and Dular at 0 (control), 6 or 13 kJ m −2 day −1 UV‐B BE”
Claim · model-written summary
Superoxide anion generation was positively correlated with increases in EC or MDA in rice leaves
- Taxon
- rice (Oryza sativa)Oryza sativat0
- Organ / stage
- leavese1
- Outcome
- increases in EC or MDAe1
- Direction
- positive correlatione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“in rice (Oryza sativa) leaves”
e1“There was a positive correlation between O 2 − generation and increases in EC or MDA in leaves”
Claim · model-written summary
UV-B exposure enhanced catalase and superoxide dismutase activities in IR74 rice relative to 0 UV-B after 14 days
- Taxon
- rice (Oryza sativa)Oryza sativat0
- Material
- IR74e3
- Treatment
- UV‐B exposuree4
- Outcome
- Activities of catalase and superoxide dismutasee4
- Direction
- enhancede4
- Qualifier
- after 14 dayse4
- Comparator
- 0 UV‐B BEe4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“in rice (Oryza sativa) leaves”
e3“Activities of enzymatic and nonenzymatic free radical scavengers were measured for IR74 after 7, 14, 21 and 28 days of exposure to 13 or 0 UV‐B BE to evaluate dynamics of these responses over time”
e4“Activities of catalase and superoxide dismutase (but not ascorbate peroxidase) and concentrations of ascorbic acid and glutathione were enhanced by 13 vs 0 UV‐B BE after 14 days of UV‐B exposure”
Claim · model-written summary
UV-B exposure did not change ascorbate peroxidase activity in rice relative to 0 UV-B
- Taxon
- rice (Oryza sativa)Oryza sativat0
- Treatment
- UV‐B exposuree4
- Outcome
- ascorbate peroxidasee4
- Direction
- no_changeinferrede4
- Comparator
- 0 UV‐B BEe4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“in rice (Oryza sativa) leaves”
e4“Activities of catalase and superoxide dismutase (but not ascorbate peroxidase) and concentrations of ascorbic acid and glutathione were enhanced by 13 vs 0 UV‐B BE after 14 days of UV‐B exposure”
Claim · model-written summary
UV-B exposure enhanced ascorbic acid and glutathione concentrations in rice relative to 0 UV-B after 14 days
- Taxon
- rice (Oryza sativa)Oryza sativat0
- Treatment
- UV‐B exposuree4
- Outcome
- concentrations of ascorbic acid and glutathionee4
- Direction
- enhancede4
- Qualifier
- after 14 dayse4
- Comparator
- 0 UV‐B BEe4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“in rice (Oryza sativa) leaves”
e4“Activities of catalase and superoxide dismutase (but not ascorbate peroxidase) and concentrations of ascorbic acid and glutathione were enhanced by 13 vs 0 UV‐B BE after 14 days of UV‐B exposure”
Claim · model-written summary
Further 28-day UV-B exposure was associated with a decline in enzyme activities and ascorbic acid in rice
- Taxon
- rice (Oryza sativa)Oryza sativat0
- Treatment
- 28 days of UV‐Be5
- Outcome
- enzyme activities and ascorbic acide5
- Direction
- declinee5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“in rice (Oryza sativa) leaves”
e5“Further exposure to 28 days of UV‐B was associated with a decline in enzyme activities and ascorbic acid, but not glutathione”
Claim · model-written summary
Further 28-day UV-B exposure was not associated with a change in glutathione in rice
- Taxon
- rice (Oryza sativa)Oryza sativat0
- Treatment
- 28 days of UV‐Be5
- Outcome
- glutathionee5
- Direction
- no_changeinferrede5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“in rice (Oryza sativa) leaves”
e5“Further exposure to 28 days of UV‐B was associated with a decline in enzyme activities and ascorbic acid, but not glutathione”
Claim · model-written summary
UV-B-induced injury in rice may be associated with disturbance of active oxygen metabolism through altered enzymatic and nonenzymatic defence systems
- Taxon
- rice (Oryza sativa)Oryza sativat0
- Outcome
- UV‐B‐induced injurye7
- Qualifier
- disturbance of active oxygen metabolisme7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“in rice (Oryza sativa) leaves”
e7“It is suggested that UV‐B‐induced injury may be associated with disturbance of active oxygen metabolism through the destruction and alteration of both enzymatic and nonenzymatic defense systems in rice”
Claim · model-written summary
Disruption of membrane systems may be an eventual reason for UV-B-induced injury in rice
- Taxon
- rice (Oryza sativa)Oryza sativat0
- Outcome
- UV‐B‐induced injurye6
- Qualifier
- disruption of membrane systemse6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“in rice (Oryza sativa) leaves”
e6“indicating that disruption of membrane systems may be an eventual reason for UV‐B‐induced injury in rice plants”
The same questions in other papers
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See all 12 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.