Details
| Original language | English |
|---|---|
| Pages (from-to) | 145-152 |
| Number of pages | 8 |
| Journal | Environmental and Experimental Botany |
| Volume | 66 |
| Issue number | 2 |
| Publication status | Published - May 2009 |
Abstract
Studies in different ecosystems have shown that plants take up intact amino acids directly but little is known about the influence of free amino acid concentrations in the soil on this process. We investigated the effect of three different soil amino acid N concentrations (0.025, 0.13 and 2.5 μg N g-1 soil) on direct uptake of four dual labelled (15N, 13C) amino acids (glycine, tyrosine, lysine, valine) in a greenhouse experiment using Anthoxantum odoratum as a model plant. Our results revealed that 8-45% of applied 15N was incorporated into plant root and shoot tissue 48 h after labelling. Additional 13C enrichment showed that 2-70% of this incorporated 15N was taken up as intact amino acid. Total 15N uptake and 15N uptake as intact amino acids were significantly affected by soil amino acid N concentrations and significantly differed between the four amino acids tested. We found a positive effect of soil amino acid concentrations on uptake of mineralized 15N relative to amino acid concentrations for all amino acids which was presumably due to higher diffusion rates of mineralized tracer to the root surface. However, intact amino acid uptake relative to amino acid concentrations as well as the proportion of total 15N taken up directly decreased with increasing soil amino acid N concentrations for all amino acids, irrespective of their microbial degradability. This effect is most likely controlled by the mineral N concentration in soil and perhaps in plants which inhibits direct amino acids uptake. Overall, we conclude that plant internal regulation of amino acid uptake controlled by mineral N is the main mechanism determining direct uptake of amino acids and thus a lower contribution of intact amino acid uptake to the plants N nutrition has to be expected for higher amino acid concentrations accompanied by mineralization in soil.
Keywords
- C, N, Microbial competition, Organic nitrogen, Plant nutrition, Stable isotope
ASJC Scopus subject areas
- Agricultural and Biological Sciences(all)
- Ecology, Evolution, Behavior and Systematics
- Agricultural and Biological Sciences(all)
- Agronomy and Crop Science
- Agricultural and Biological Sciences(all)
- Plant Science
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In: Environmental and Experimental Botany, Vol. 66, No. 2, 05.2009, p. 145-152.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Uptake of intact amino acids by plants depends on soil amino acid concentrations
AU - Sauheitl, L.
AU - Glaser, B.
AU - Weigelt, A.
N1 - Funding information: We thank the German Research Foundation (GL 327/4,4) and the Hanns-Seidel-Stiftung for financial support of this study. Special thanks go to the Prof. Dr. E. Steudle, chair for plant physiology of the University of Bayreuth, and Prof. Dr. G. Gebauer, Centre of Stable Isotope Analysis in Bayreuth, for providing a climatic chamber and laboratory work place. Michael Zech provided helpful comments to an earlier draft of the manuscript.
PY - 2009/5
Y1 - 2009/5
N2 - Studies in different ecosystems have shown that plants take up intact amino acids directly but little is known about the influence of free amino acid concentrations in the soil on this process. We investigated the effect of three different soil amino acid N concentrations (0.025, 0.13 and 2.5 μg N g-1 soil) on direct uptake of four dual labelled (15N, 13C) amino acids (glycine, tyrosine, lysine, valine) in a greenhouse experiment using Anthoxantum odoratum as a model plant. Our results revealed that 8-45% of applied 15N was incorporated into plant root and shoot tissue 48 h after labelling. Additional 13C enrichment showed that 2-70% of this incorporated 15N was taken up as intact amino acid. Total 15N uptake and 15N uptake as intact amino acids were significantly affected by soil amino acid N concentrations and significantly differed between the four amino acids tested. We found a positive effect of soil amino acid concentrations on uptake of mineralized 15N relative to amino acid concentrations for all amino acids which was presumably due to higher diffusion rates of mineralized tracer to the root surface. However, intact amino acid uptake relative to amino acid concentrations as well as the proportion of total 15N taken up directly decreased with increasing soil amino acid N concentrations for all amino acids, irrespective of their microbial degradability. This effect is most likely controlled by the mineral N concentration in soil and perhaps in plants which inhibits direct amino acids uptake. Overall, we conclude that plant internal regulation of amino acid uptake controlled by mineral N is the main mechanism determining direct uptake of amino acids and thus a lower contribution of intact amino acid uptake to the plants N nutrition has to be expected for higher amino acid concentrations accompanied by mineralization in soil.
AB - Studies in different ecosystems have shown that plants take up intact amino acids directly but little is known about the influence of free amino acid concentrations in the soil on this process. We investigated the effect of three different soil amino acid N concentrations (0.025, 0.13 and 2.5 μg N g-1 soil) on direct uptake of four dual labelled (15N, 13C) amino acids (glycine, tyrosine, lysine, valine) in a greenhouse experiment using Anthoxantum odoratum as a model plant. Our results revealed that 8-45% of applied 15N was incorporated into plant root and shoot tissue 48 h after labelling. Additional 13C enrichment showed that 2-70% of this incorporated 15N was taken up as intact amino acid. Total 15N uptake and 15N uptake as intact amino acids were significantly affected by soil amino acid N concentrations and significantly differed between the four amino acids tested. We found a positive effect of soil amino acid concentrations on uptake of mineralized 15N relative to amino acid concentrations for all amino acids which was presumably due to higher diffusion rates of mineralized tracer to the root surface. However, intact amino acid uptake relative to amino acid concentrations as well as the proportion of total 15N taken up directly decreased with increasing soil amino acid N concentrations for all amino acids, irrespective of their microbial degradability. This effect is most likely controlled by the mineral N concentration in soil and perhaps in plants which inhibits direct amino acids uptake. Overall, we conclude that plant internal regulation of amino acid uptake controlled by mineral N is the main mechanism determining direct uptake of amino acids and thus a lower contribution of intact amino acid uptake to the plants N nutrition has to be expected for higher amino acid concentrations accompanied by mineralization in soil.
KW - C
KW - N
KW - Microbial competition
KW - Organic nitrogen
KW - Plant nutrition
KW - Stable isotope
UR - http://www.scopus.com/inward/record.url?scp=67349259721&partnerID=8YFLogxK
U2 - 10.1016/j.envexpbot.2009.03.009
DO - 10.1016/j.envexpbot.2009.03.009
M3 - Article
AN - SCOPUS:67349259721
VL - 66
SP - 145
EP - 152
JO - Environmental and Experimental Botany
JF - Environmental and Experimental Botany
SN - 0098-8472
IS - 2
ER -