Abstract
The roles of light and temperature in the accumulation of the vegetal impact compound 2-methoxy-3-isobutylpyrazine (MIBP) in grape (Vitis vinifera L.) berries were determined. Individual clusters were exposed to various light intensities using neutral density shade cloth before ripening, during ripening or throughout the season in three growing seasons. A recently developed method using headspace solid-phase microextraction combined with GC-MS in the selected ion-monitoring mode was employed to measure MIBP in berries. Berry MIBP concentration increased subsequent to berry set, reached a maximum prior to onset of ripening, and then decreased thereafter until harvest. Complete shading of clusters increased the concentration of MIBP more than 100% compared to unshaded controls in 2 out of 3 years. Light increasingly inhibited MIBP concentrations up to 25-50% of ambient light intensities (1500 µmol photons m(-2) s(-1) ). However, only changes in light intensity before ripening had any effect on MIBP accumulation or final MIBP concentration. Analyses of weather data showed that the 1 year in which shading was ineffective was unusually warm, warm early in the season, and had more hot days and higher early season degree days than the other 2 years. In controlled environment experiments, warm growth conditions reduced MIBP concentrations in fruit about as much as light exposure reduced MIBP concentrations in the field experiments. The results indicate that both light and temperature significantly affect MIBP in harvested fruit, but that the light environment during ripening does not significantly affect MIBP concentrations in the berries at harvest.
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Claims 7
Claim · model-written summary
Berry MIBP rose after berry set, peaked before ripening and declined until harvest.
Verbatim
e0“Berry MIBP concentration increased subsequent to berry set, reached a maximum prior to onset of ripening, and then decreased thereafter until harvest.”
Claim · model-written summary
Complete cluster shading raised MIBP concentration more than 100% versus unshaded controls in two of three years.
- Taxon
- grape (Vitis vinifera L.)
Vitis viniferat0 - Treatment
- Complete shading of clusterse0
- Outcome
- concentration of MIBPe0
- Direction
- increasede0
- Value
- more than 100%e0
- Qualifier
- 2 out of 3 yearse0
- Comparator
- unshaded controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Complete shading of clusters increased the concentration of MIBP more than 100% compared to unshaded controls in 2 out of 3 years.”
t0“grape (Vitis vinifera L.)”
Claim · model-written summary
Light increasingly inhibited MIBP concentrations up to 25-50% of ambient intensity.
- Taxon
- grape (Vitis vinifera L.)Vitis viniferat0
- Treatment
- Lighte0
- Outcome
- MIBP concentrationse0
- Direction
- inhibitede0
- Value
- 25-50% of ambient light intensitiese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Light increasingly inhibited MIBP concentrations up to 25-50% of ambient light intensities (1500 µmol photons m(-2) s(-1) ).”
t0“grape (Vitis vinifera L.)”
Claim · model-written summary
Only pre-ripening light changes affected MIBP accumulation or final concentration.
- Taxon
- grape (Vitis vinifera L.)Vitis viniferat0
- Treatment
- changes in light intensity before ripeninge0
- Outcome
- MIBP accumulation or final MIBP concentratione0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“However, only changes in light intensity before ripening had any effect on MIBP accumulation or final MIBP concentration.”
t0“grape (Vitis vinifera L.)”
Claim · model-written summary
The year when shading was ineffective was unusually warm, especially early in the season.
- Taxon
- grape (Vitis vinifera L.)Vitis viniferat0
- Outcome
- shading was ineffectivee0
- Qualifier
- unusually warm, warm early in the season, and had more hot days and higher early season degree dayse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the 1 year in which shading was ineffective was unusually warm, warm early in the season, and had more hot days and higher early season degree days than the other 2 years.”
t0“grape (Vitis vinifera L.)”
Claim · model-written summary
Warm growth conditions reduced fruit MIBP about as much as field light exposure.
- Taxon
- grape (Vitis vinifera L.)Vitis viniferat0
- Treatment
- warm growth conditionse0
- Outcome
- MIBP concentrations in fruite0
- Direction
- reducede0
- Comparator
- light exposuree0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“warm growth conditions reduced MIBP concentrations in fruit about as much as light exposure reduced MIBP concentrations in the field experiments.”
t0“grape (Vitis vinifera L.)”
Claim · model-written summary
Light during ripening did not significantly affect MIBP at harvest.
- Taxon
- grape (Vitis vinifera L.)Vitis viniferat0
- Treatment
- light environment during ripeninge0
- Outcome
- MIBP concentrations in the berries at harveste0
- Direction
- does not significantly affecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the light environment during ripening does not significantly affect MIBP concentrations in the berries at harvest.”
t0“grape (Vitis vinifera L.)”
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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.