Characteristics of amino acid uptake in barley |
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Authors: | Sandra Jämtgård Torgny Näsholm Kerstin Huss-Danell |
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Institution: | 1. Crop Science Section, Department of Agricultural Research for Northern Sweden, Swedish University of Agricultural Sciences, S-904 03, Ume?, Sweden 2. Ume? Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 83, Ume?, Sweden
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Abstract: | Plants have the ability to take up organic nitrogen (N) but this has not been thoroughly studied in agricultural plants. A
critical question is whether agricultural plants can acquire amino acids in a soil ecosystem. The aim of this study was to
characterize amino acid uptake capacity in barley (Hordeum vulgare L.) from a mixture of amino acids at concentrations relevant to field conditions. Amino acids in soil solution under barley
were collected in microlysimeters. The recorded amino acid composition, 0–8.2 μM of l-Serine, l-Glutamic acid, Glycine, l-Arginine and l-Alanine, was then used as a template for uptake studies in hydroponically grown barley plants. Amino acid uptake during 2 h
was studied at initial concentrations of 2–25 μM amino acids and recorded as amino acid disappearance from the incubation
solution, analysed with HPLC. The uptake was verified in control experiments using several other techniques. Uptake of all
five amino acids occurred at 2 μM and below. The concentration dependency of the uptake rate could be described by Michaelis–Menten
kinetics. The affinity constant (K
m) was in the range 19.6–33.2 μM. These K
m values are comparable to reported values for soil micro-organisms. |
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Keywords: | Active uptake Affinity constant Amino acids in soil solution Efflux Nitrogen acquisition Organic nitrogen |
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