Table II.
Proportion and amount of Zn malate and Zn phosphate species in the plant samples
| Sample | [Zn]sol. | [Zn] | EXAFS
|
Chemical Analyses
|
||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Proportion of Zn speciesa
|
Concentrationsb
|
Concentrations
|
||||||||||
| Zn Malate | Zn Phosphate | NSS ×10−2c | Zn Malate | Zn Phosphate | Malate | P | ||||||
| μM | μmol g−1 | molar % of total Zn | μmol g-1 | μmol g−1 | ||||||||
| Aerial parts | ||||||||||||
| A.h.-C | 250 | 160 ± 1 | 100 ± 10 | 0 ± 10 | 2.5 | 160 ± 17 | 0 ± 16 | 165 ± 24 | 67 ± 2 | |||
| 100 | 62 ± 1 | 100 ± 10 | 0 ± 10 | 4.1 | 62 ± 7 | 0 ± 6 | 144 ± 28 | 74 ± 6 | ||||
| 10 | 11 ± 2 | 67 ± 10 | 33 ± 10 | 5.6 | 7 ± 3 | 4 ± 2 | 113 ± 6 | 67 ± 12 | ||||
| A.h.-NC | 250 | 217 ± 19 | 100 ± 10 | 0 ± 10 | 5.9 | 217 ± 43 | 0 ± 24 | 221 ± 35 | 73 ± 7 | |||
| 100 | 80 ± 3 | 100 ± 10 | 0 ± 10 | 3.3 | 80 ± 11 | 0 ± 8 | 111 ± 32 | 56 ± 7 | ||||
| A.l. | 10 | 6 ± 0 | 0 ± 10 | 100 ± 10 | 13.4 | 0 ± 1 | 6 ± 1 | 220 ± 22 | 77 ± 3 | |||
| A.h.-C (soil) | − | 169 ± 8 | 100 ± 10 | 0 ± 10 | 3.9 | 169 ± 26 | 0 ± 18 | 447 ± 26 | 95 ± 2 | |||
| Roots | ||||||||||||
| A.h.-C | 250 | 218 ± 15 | 0 ± 10 | 100 ± 10 | 9.4 | 0 ± 23 | 218 ± 38 | 2 ± 1 | 469 ± 5 | |||
| 100 | 105 ± 15 | 0 ± 10 | 100 ± 10 | 14.8 | 0 ± 12 | 105 ± 27 | 6 ± 1 | 419 ± 57 | ||||
| 10 | 17 ± 4 | 0 ± 10 | 100 ± 10 | 9.4 | 0 ± 2 | 17 ± 6 | 6 ± 0 | 181 ± 45 | ||||
| A.h.-NC | 250 | 218 ± 30 | 0 ± 10 | 100 ± 10 | 7.4 | 0 ± 25 | 218 ± 55 | 5 ± 2 | 551 ± 54 | |||
| 100 | 74 ± 13 | 0 ± 10 | 100 ± 10 | 10.9 | 0 ± 9 | 74 ± 22 | 21 ± 6 | 239 ± 47 | ||||
| A.l. | 10 | 46 ± 2 | 0 ± 10 | 100 ± 10 | 10.3 | 0 ± 5 | 46 ± 7 | 10 ± 4 | 292 ± 2 | |||
| A.h.-C (soil)d | − | 112 ± 11 | 75 ± 10 | 25 ± 10 | 3.6 | 84 ± 21 | 28 ± 15 | 36 ± 5 | 70 ± 5 | |||
| Zn Malate | Zn Citrate | Zn Phosphate | Zn Malate | Zn Citrate | Zn Phosphate | Malate | Citrate | P | ||||
| 29 ± 10 | 39 ± 10 | 32 ± 10 | 5.3 | 33 ± 15 | 44 | 35 ± 16 | 36 ± 5 | 138 ± 24 | 70 ± 5 | |||
Proportions of Zn species (in molar % of total Zn) were determined by simulating the plant EXAFS spectra by a linear combination of Zn malate and Zn phytate spectra (Fig. 3).
Concentrations are calculated from the proportion of the two species and the total Zn concentrations (Table I).
The quality of the fit is estimated by: NSS = Σ [k3 χ (k)exp − k3 χ (k)reconstr.]2/Σ [k3χ (k)exp]2).
For this sample, two Zn distributions are given, one including Zn malate and Zn phytate, and one including Zn citrate as well. The error bars correspond to an uncertainty of 10% for the proportion of Zn species, to the sd over three samples for the measured concentrations, and to the combination of both uncertainties for the deduced concentrations of Zn species.