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The occurrence of amino acids in agricultural soil and their uptake by plants

Jämtgård, Sandra (2010). The occurrence of amino acids in agricultural soil and their uptake by plants. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2010:27
ISBN 978-91-576-7504-0
[Doctoral thesis]

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Abstract

The ability of plants to take up amino acids is widespread among plants, but the ecological and physiological implications of this ability are not fully understood. Therefore, in the investigations this thesis is based upon, key aspects of the uptake of amino acids by agricultural plants were explored in field studies (to ensure ecological relevance) and laboratory analyses (to ensure precision). Small tension lysimeters were used to collect soil solution from several agricultural soils with minimal disturbance. Concentrations of free amino acids were found to be low (0- 12.7 μM). However, they may be continuously replenished from bound amino acid pools and were found to be sufficiently high (generally) for uptake by hydroponically grown barley, Hordeum vulgare L., and Arabidopsis, Arabidopsis thaliana L. Hence, the effective minimum concentrations for uptake by these species do not seem to exceed most of the field-measured concentrations. The uptake affinity in both barley and Arabidopsis was found to be comparable to reported values for nitrate at corresponding concentrations and for uptake of amino acids by soil micro-organisms. The amino acid transporters lysine histidine transporter 1 (LHT1) and amino acid permease 5 (AAP5) were found to be largely responsible for amino acid uptake in Arabidopsis at these concentrations. These transporters have complementary affinities for amino acids with differing properties; LHT1 transporting acidic and neutral amino acids, and AAP5 basic amino acids. Furthermore, the gene expression of LHT1 and AAP5 clearly increased after roots were exposed to amino acids, even in the presence of inorganic nitrogen, resulting in up to 15-fold increases in the rate of amino acid uptake. The induced amino acid uptake rates were up to 10-fold higher than nitrate uptake rates in Arabidopsis. According to standard textbooks, nitrate and ammonium are the major nitrogen sources for plants. However, the results of these studies indicate that plants have the capacity to take up amino acids at field concentrations in presence of nitrate and ammonium. This capacity requires gene expression, synthesis and regulation of amino acid transporters, and the ability of plants to sense and respond to amino acid concentrations at ambient concentrations. There is, therefore, little doubt that plants can take up amino acids in their natural environment. Thus, it is time to reconsider traditional views of the nitrogen compounds used by agricultural plants.Keywords: Arabidopsis thaliana, barley, Bound amino acids, Free amino acids, Induction, Inorganic nitrogen, Lysimeter, Nitrogen, Amino acid transporter

Authors/Creators:Jämtgård, Sandra
Title:The occurrence of amino acids in agricultural soil and their uptake by plants
Year of publishing :2010
Volume:2010:27
Number of Pages:52
Papers/manuscripts:
NumberReferences
ALLI. Jämtgård S, Näsholm T and Huss-Danell K. Nitrogen compounds in soil solutions of agricultural land. (submitted) II. Jämtgård S, Näsholm T and Huss-Danell K (2008). Characteristics of amino acid uptake in barley. Plant and Soil 302, 221-231. III. Svennerstam H, Jämtgård S, Huss-Danell K, Näsholm T and Ganeteg U. Transporters in Arabidopsis roots mediating uptake of amino acids at field relevant concentrations. (manuscript) IV. Jämtgård S, Holmlund M, Cambui Aguetoni C, Inselsbacher E, Huss- Danell K and Näsholm T. Induction of amino acid uptake in Arabidopsis and barley. (manuscript)
Place of Publication:Umeå
ISBN for printed version:978-91-576-7504-0
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:arabidopsis thaliana, hordeum vulgare, agricultural soils, amino acids, nitrogen, nutrient uptake, lysimeters, laboratory experimentation, field experimentation, sweden
Keywords:Arabidopsis thaliana, barley, Bound amino acids, Free amino acids, Induction, Inorganic nitrogen, Lysimeter, Nitrogen, Amino acid transporters
URN:NBN:urn:nbn:se:slu:epsilon-3072
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-3072
ID Code:2286
Department:(NL, NJ) > Dept. of Agricultural Research for Northern Sweden
(VH) > Dept. of Agricultural Research for Northern Sweden
Deposited By: Sandra Jämtgård
Deposited On:07 May 2010 00:00
Metadata Last Modified:02 Dec 2014 10:17

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