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Manipulation of contents of nitrate, phenolic acids, chlorophylls and carotenoids in lettuce (Lactuca sativa L.) via contrasting responses to nitrogen fertilizer when grown in a controlled environment. Othman Qadir, Mario Siervo, Christopher John Seal, and Kirsten Brandt J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.7b03675 • Publication Date (Web): 23 Oct 2017 Downloaded from http://pubs.acs.org on October 25, 2017
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Journal of Agricultural and Food Chemistry is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
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Journal of Agricultural and Food Chemistry
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Manipulation of contents of nitrate, phenolic acids, chlorophylls and
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carotenoids in lettuce (Lactuca sativa L.) via contrasting responses to
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nitrogen fertilizer when grown in a controlled environment.
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Othman Qadir1, 2, *, Mario Siervo1, Chris J. Seal1, Kirsten Brandt1
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Newcastle upon Tyne, NE4 5PL, UK.
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Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University,
Food Science and Human Nutrition Dept., Faculty of Agricultural Sciences, University of Sulaimani,
Sulaymaniah, 46001, Iraqi Kurdistan Region.
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* Corresponding author: +44 7925417105,
[email protected] 13 14 15 16 17 18 19 20 21 22 23 24 25 26
ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
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ABSTRACT
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This study aimed to use different nitrogen fertilizer regimes to produce Butterhead lettuce with such
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large differences in nitrate content that they could be used as treatment and placebo to study the effect
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of inorganic nitrate on human health. Plants were grown under controlled conditions at 27/23°C
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day/night with a relatively low Photosyntetically Active Radiation (PAR) of 150μmol m-2 s-1 for 14
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hours day-1 and nitrogen supplies ranging from 26 to 154ppm N as ammonium nitrate in the
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fertigation solution. This resulted in contrasting high (~1078 mg nitrate 100g-1 FW) or low (~6 mg
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100g-1) nitrate contents in the leaves. Contents of carotenoids and chlorophylls in fresh weight did
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not differ significantly between highest and lowest N-supply levels. However, increased nitrogen
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supply reduced contents of phenolic compounds from 154 to 22mg 100g-1 FW, dry matter content
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from 8.9 to 4.6% and fresh weight per plant from 108.52 to 47.57 g/plant FW (all P