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Direct amino acid uptake by plants related to grassland diversity [Elektronische Ressource] : methodological and ecological investigations / vorgelegt von Leopold Sauheitl

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198 pages
Direct Amino Acid Uptake by Plants related to Grassland Diversity - methodological and ecological Investigations Dissertation zur Erlangung des Doktorgrades in den Naturwissenschaften (Dr. rer. nat.) an der Fakultät für Biologie / Chemie / Geowissenschaften der Universität Bayreuth vorgelegt von Leopold Sauheitl (Dipl. Geoökologe) geb. am 23.10.1978 in Regen Erstgutachter: PD Dr. Bruno Glaser Bayreuth, Oktober 2009 Die vorliegende Arbeit wurde in dem Zeitraum von Dezember 2005 bis Oktober 2009 an der Universtität Bayreuth unter der Leitung von Doktor B. Glaser erstellt. Vollständiger Abdruck der von der Fakultät Biologie, Chemie und Geowissenschaften der Universität Bayreuth genehmigten Dissertation zur Erlangung des akademischen Grades Doktor der Naturwissenschaften (Dr. rer. nat.). Erster Prüfer: Dr. PD Bruno Glaser Zweiter Prüfer: Prof. Dr. Yakov Kuzyakov Dritter Prüfer: Prof. Dr. Gerhard Gebauer Vierter Prüfer: Prof. Dr. Ewald Komor Prüfungsvorsitz: Prof. Dr. Ortwin Meyer Tag der Einreichung: 21.10.2009 Zulassung zur Promotion: 28.10.2009 Auslage der Arbeit: 26.11.2009 – 09.12.2009 Kolloquium: 18.12.2009 Direct Amino Acid Uptake by Plants related to Grassland Diversity - methodological and ecological Investigations by Leopold Sauheitl >>In nature, one plus one is not necessarily always two – and even the old wise men in the Israelite desert know this.<< Prof.
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Direct Amino Acid Uptake by Plants
related to Grassland Diversity
-
methodological and ecological Investigations


Dissertation
zur Erlangung des Doktorgrades
in den Naturwissenschaften
(Dr. rer. nat.)
an der Fakultät für Biologie / Chemie / Geowissenschaften
der Universität Bayreuth



vorgelegt von
Leopold Sauheitl (Dipl. Geoökologe)
geb. am 23.10.1978 in Regen

Erstgutachter: PD Dr. Bruno Glaser

Bayreuth, Oktober 2009

Die vorliegende Arbeit wurde in dem Zeitraum von Dezember 2005 bis Oktober 2009
an der Universtität Bayreuth unter der Leitung von Doktor B. Glaser erstellt.




Vollständiger Abdruck der von der Fakultät Biologie, Chemie und Geowissenschaften
der Universität Bayreuth genehmigten Dissertation zur Erlangung des akademischen
Grades Doktor der Naturwissenschaften (Dr. rer. nat.).




Erster Prüfer: Dr. PD Bruno Glaser
Zweiter Prüfer: Prof. Dr. Yakov Kuzyakov
Dritter Prüfer: Prof. Dr. Gerhard Gebauer
Vierter Prüfer: Prof. Dr. Ewald Komor
Prüfungsvorsitz: Prof. Dr. Ortwin Meyer




Tag der Einreichung: 21.10.2009
Zulassung zur Promotion: 28.10.2009
Auslage der Arbeit: 26.11.2009 – 09.12.2009
Kolloquium: 18.12.2009
Direct Amino Acid Uptake by Plants
related to Grassland Diversity
-
methodological and ecological Investigations

by Leopold Sauheitl








>>In nature, one plus one
is not necessarily always two

and even the old wise men
in the Israelite desert know this.<<

Prof. Dr. Daniel Hillel
EUROSOIL congress 2008 I
Index of contents

Index of tables and figures........................................................................................... VIII
Tables....................................................................................................................... VIII
FiguresXII
Abbreviations................................................................................................................ XV
Summary...................................................................................................................... XIX
Zusammenfassung ....................................................................................................... XXI
I) Extended Summary 1
1. Introduction............................................................................................................... 1
1.1 Preface ................................................................................................................ 1
1.2 Possible ecological impact of amino acid uptake ............................................... 1
1.3 Relevance of amino acid uptake in plant diversity experiments ........................ 2
1.4 Methodological considerations ........................................................................... 3
1.5 Objectives ........................................................................................................... 6
2 Greenhouse experiments............................................................................................ 7
3 Field experiments....................................................................................................... 7
3.1 Experimental site ................................................................................................ 7
3.2 Experiments on methodological considerations ................................................. 8
3.3 Experiment on amino acid uptake in a plant diversity gradient ......................... 9
4 Analytical methods .................................................................................................. 10
4.1 Amino acids ...................................................................................................... 10
4.2 Phospholipid fatty acids (PLFA) ...................................................................... 11
4.3 Soil microbial biomass...................................................................................... 11
4.4 Mineral soil N ................................................................................................... 11
4.5 Bulk isotope measurements .............................................................................. 11
II
4.6 Compound specific measurements....................................................................12
4.7 Calculation of tracer uptake ..............................................................................12
5 Results and Discussion.............................................................................................12
5.1 Effect of soil amino acid concentration on direct amino acid uptake (Study 1)12
5.2 Suitability of bulk vs. CSI measurements for accurate quantification of amino
acid uptake (Studies 2, 3) ........................................................................................13
5.3 Soil amino acid fingerprint (Study 4)................................................................15
5.4 Influence of plant diversity on direct amino acid uptake by plants and the
importance of microbial competition (Study 5) ......................................................16
5.5 Changes in microbial community structure and metabolic activity (Study 6)..18
6 Conclusions ..............................................................................................................19
7 Contribution to the included manuscripts and publications .....................................21
Literature .................................................................................................................24
II) Cumulative Publications and Manuscripts.................................................................31
Study 1: Uptake of intact amino acids by plants depends on soil amino acid
concentrations.33
1 Introduction ..............................................................................................................35
2 Materials and Methods .............................................................................................37
2.1 Planting..............................................................................................................37
2.2 Labelling............................................................................................................38
2.3 Sample preparation............................................................................................39
2.4 Instrumentation..................................................................................................40
2.5 Calculation ........................................................................................................40
2.6 Statistics41
3 Results ......................................................................................................................42
3.1. Total N and amino acid N uptake.....................................................................42
III
3.2. Uptake efficiencies of total N and amino acid N uptake ................................. 43
3.3. Amino acid N as proportion of total N uptake................................................. 43
4 Discussion................................................................................................................ 46
154.1 Abiotic mechanisms controlling total N uptake and direct amino acid uptake
................................................................................................................................ 46
4.2 Biotic mechanisms regulating direct amino acid uptake .................................. 47
4.3 Effect of different amino acids and their concentration ................................... 48
5 Conclusions.............................................................................................................. 50
Acknowledgement ...................................................................................................... 50
Literature..................................................................................................................... 51
Study 2: Advantages of compound-specific stable isotope measurements over bulk
measurements in studies on plant uptake of intact amino acids ..................................... 55
1 Introduction 57
2 Material and Methods .............................................................................................. 60
2.1 Field site............................................................................................................ 60
2.2 Labelling ........................................................................................................... 60
2.3 Sampling and sample preparation..................................................................... 61
2.4 Amino acid extraction, purification and derivatization .................................... 61
2.5 Measurement..................................................................................................... 62
2.6 Calculations ...................................................................................................... 63
2.7 Statistics............................................................................................................ 65
3 Results...................................................................................................................... 65
3.1 Comparison of bulk and CSI measurements..................................................... 65
3.2 Isotope enrichment in single amino acids......................................................... 67
4 Discussion................................................................................................................ 69
4.1 Validity of compared data................................................................................. 69
IV
4.2 Overestimation of direct amino acid uptake by bulk measurements ................71
4.3 Additional information from CSI measurements..............................................73
5 Conclusions ..............................................................................................................75
Acknowledgment ........................................................................................................76
Literature .....................................................................................................................77
Study 3: Plant uptake of dual-labelled organic N biased by ...........................................81
inorganic C uptake: results of a triple labelling study.....................................................81
1 Introduction ..............................................................................................................83
2 Material and Methods...............................................................................................83
3 Results and Discussion.............................................................................................85
Acknowledgement.......................................................................................................88
References ...................................................................................................................89
Study 4: Amino acid fingerprint of soils reflects plant diversity changes in a grassland
ecosystem ........................................................................................................................91
1 Introduction ..............................................................................................................93
2 Methods....................................................................................................................94
2.1 Soil sampling.....................................................................................................94
2.2 Amino acid extraction, purification and derivatization.....................................94
2.3 Measurements....................................................................................................95
2.4 Calculations and Statistics.................................................................................96
3 Results and Discussion.............................................................................................97
4 Conclusions ............................................................................................................102
Acknowledgement.....................................................................................................103
References .................................................................................................................104
Study 5: Plant diversity affects the outcome of competition between plants and
microbes for organic N..................................................................................................109
V
1 Introduction............................................................................................................ 111
2 Material and Methods ............................................................................................ 113
2.1 Study area ....................................................................................................... 113
2.2 Labelling ......................................................................................................... 114
2.3 Sampling 115
2.4 Amino acid extraction from plant material..................................................... 115
2.5 Extraction of free amino acids in soil ............................................................. 115
2.6 Extraction of microbial biomass ..................................................................... 116
2.7 Substance specific isotope measurements of plant material........................... 116
2.8 Bulk measurements of plant material ............................................................. 117
2.9 Analysis of microbial C and N ....................................................................... 117
3 Calculations and Statistics ..................................................................................... 117
3.1 Calculation of tracer uptake............................................................................ 117
3.2 Statistics.......................................................................................................... 120
4 Results.................................................................................................................... 121
4.1 Plant biomass .................................................................................................. 121
4.2 Mineral soil N ................................................................................................. 121
4.3 Microbial biomass........................................................................................... 122
4.4 Microbial tracer uptake................................................................................... 123
4.5 Plant tracer uptake .......................................................................................... 124
4.6 Total plant nitrogen and amino acid uptake.................................................... 125
5 Discussion.............................................................................................................. 127
5.1 Plant and microbial biomass ........................................................................... 127
5.2 Microbial and plant tracer uptake ................................................................... 128
5.3 Total N and amino acid uptake by plants ....................................................... 129
5.4 A temporal point of view................................................................................ 132

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