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SUPPLEMENTARY DATA
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Table S1. Sand physical properties including parameters used in the van Genuchten
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equation.
Ksat
θs
θr
α
(m.d-1)
(cm3/cm3)
(cm3/cm3)
(hPa-1)
Redhill T
1.81
3.97
0.92
0.02
0.77
<250 μm
1.42
4.49
0.99
0.02
0.84
250-425 μm
2.01
4.42
1.06
0.03
0.89
>425 μm
3.23
4.34
1.02
0.03
0.89
m
Sand
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Table S2. Standard error differences (SED) and least squared difference (LSD, 5%) values
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of RSA characteristics for each physiology experiment (Exp).
Agar v Sand
Particle Size
Water Tension
[NO3-] Agar
[NO3-] Sand
SED
LSD
SED
LSD
SED
LSD
SED
LSD
SED
LSD
PRL
0.079
0.158
1.570
3.197
1.512
3.038
0.786
1.587
1.700
3.416
SRL
0.203
0.407
1.316
2.681
0.865
1.224
0.656
1.325
0.859
1.726
LRN
0.136
0.272
0.355
0.724
0.200
0.401
0.310
0.626
0.207
0.416
TLRL
0.198
0.397
1.225
2.496
0.710
1.426
0.967
1.951
0.477
0.959
Exp
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Supplementary Figure S1. Water release characteristics of the sands used in these
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experiments. The water release characteristic was measured using the Burette method (A;
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arrows indicate the tensions used during the water tension experiment) and Ksat was measured
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using the constant head permeability test (B). This information was computed using the van
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Genuchten model to calculate Kunsat (C).
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Supplementary Figure S2. Typical NO3- microelectrode recording obtained from the
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surface of an Arabidopsis root growing in sand and supplied with a full nutrient solution
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containing 0.1 mM NO3-. Stable measurements were recorded at the root tip (RT) and 2 mm
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up (RT-2 mm) from the RT of an intact primary root. The recording shows the calibration of
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the microelectrode before (t= 0 to 10 min) and after (t= 25 to 32 min) the measurement with
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solutions of known NO3- activity (100 mM, 10 mM, 1mM, 0.1 mM and 0.01 mM).