Abstract
Abstract Commercial cultivars of onion ( Allium cepa L.) were grown at Torslunda research station, Sweden with different levels of nitrogen fertiliser and lifted at different growth stages. Soon after lifting, before any drying or curing, tissue from the fleshy edible part of onions was extracted in ethanol and the raw extracts were analysed by high‐performance liquid chromatography without any previous hydrolysis. It was confirmed that the main flavonoid compounds were quercetin monoglucoside and quercetin diglucoside, whereas only trace amounts of quercetin aglycone and other flavonoids were found. The greatest variation in quercetin content, in the range 100–500 mg kg −1 fresh weight, occurred between years. The concentration of quercetin glucosides in the onions was strongly correlated ( R 2 = 0.98) with the total amount of global radiation in August. Individual onions with fallen leaves had significantly higher concentrations of quercetin glucosides than individuals in the same row with erect leaves. Only minor differences were found between the three cultivars analysed. Higher levels of nitrogen fertiliser had only minor effects on onion yield and size and resulted in lower or equal amounts of quercetin glucosides. Nitrogen leakage from the soil, a potential source of environmental problems, could therefore be minimised by avoiding high nitrogen fertiliser levels with almost no effect on onion flavonol content. Late lifting of onions (80% fallen leaves) resulted in up to 45% higher concentrations of quercetin glucosides compared with early lifting (50% fallen leaves). Copyright © 2006 Society of Chemical Industry
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Claims 10
Claim · model-written summary
Quercetin monoglucoside and diglucoside were the main onion flavonoids.
- Outcome
- main flavonoid compounds were quercetin monoglucoside and quercetin diglucosidee0
Not reportedTaxon
Verbatim
e0“the main flavonoid compounds were quercetin monoglucoside and quercetin diglucoside”
Claim · model-written summary
Only trace quercetin aglycone and other flavonoids were found.
- Taxon
- onion
Allium cepat0 - Outcome
- trace amounts of quercetin aglycone and other flavonoidse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“onion”
e0“only trace amounts of quercetin aglycone and other flavonoids were found”
Claim · model-written summary
Between year variation in onion quercetin content ranged from 100 to 500 mg per kg fresh weight.
- Taxon
- onionAllium cepat0
- Outcome
- quercetin contente0
- Value
- 100–500 mg kg −1 fresh weighte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“onion”
e0“The greatest variation in quercetin content, in the range 100–500 mg kg −1 fresh weight, occurred between years.”
Claim · model-written summary
Onion quercetin glucoside concentration was strongly correlated with August global radiation.
- Taxon
- onionsAllium cepae0
- Outcome
- concentration of quercetin glucosidese0
- Qualifier
- R 2 = 0.98e0
- Setting
- Auguste0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The concentration of quercetin glucosides in the onions was strongly correlated ( R 2 = 0.98) with the total amount of global radiation in August.”
Claim · model-written summary
Onions with fallen leaves had higher quercetin glucoside concentrations than those with erect leaves.
- Taxon
- onionsAllium cepae0
- Organ / stage
- fallen leavese0
- Outcome
- concentrations of quercetin glucosidese0
- Direction
- highere0
- Comparator
- erect leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Individual onions with fallen leaves had significantly higher concentrations of quercetin glucosides than individuals in the same row with erect leaves.”
Claim · model-written summary
Quercetin content differed only slightly among the three onion cultivars.
- Taxon
- onionAllium cepat0
- Material
- three cultivarse0
- Outcome
- minor differencese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“onion”
e0“Only minor differences were found between the three cultivars analysed.”
Claim · model-written summary
Higher nitrogen fertilizer levels had only minor effects on onion yield and size.
- Taxon
- onionAllium cepae0
- Treatment
- Higher levels of nitrogen fertilisere0
- Outcome
- onion yield and sizee0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Higher levels of nitrogen fertiliser had only minor effects on onion yield and size”
Claim · model-written summary
Higher nitrogen fertilizer levels yielded lower or equal onion quercetin glucoside amounts.
- Taxon
- onionAllium cepae0
- Treatment
- Higher levels of nitrogen fertilisere0
- Outcome
- amounts of quercetin glucosidese0
- Direction
- lower or equale0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Higher levels of nitrogen fertiliser had only minor effects on onion yield and size and resulted in lower or equal amounts of quercetin glucosides.”
Claim · model-written summary
Late lifting produced up to 45% higher onion quercetin glucoside concentrations than early lifting.
- Taxon
- onionsAllium cepae0
- Treatment
- Late lifting of onions (80% fallen leaves)e0
- Outcome
- concentrations of quercetin glucosidese0
- Direction
- highere0
- Value
- up to 45%e0
- Comparator
- early lifting (50% fallen leaves)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Late lifting of onions (80% fallen leaves) resulted in up to 45% higher concentrations of quercetin glucosides compared with early lifting (50% fallen leaves).”
Claim · model-written summary
The authors advised avoiding high nitrogen fertilizer to minimize soil nitrogen leakage with little effect on flavonol content.
- Taxon
- onionAllium cepae0
- Outcome
- avoiding high nitrogen fertiliser levelse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen leakage from the soil, a potential source of environmental problems, could therefore be minimised by avoiding high nitrogen fertiliser levels with almost no effect on onion flavonol content.”
The same questions in other papers
fertilization · molecular: metabolites · Allium cepa (onion)Positive and negative results
12 papers in the same direction as this paper · 18 in the opposite direction
- no effect
- no effect
- positive
27 papers more in this group
See all 31 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.