Table 2.
Ion distribution within plants reveals distinct, cell-specific patterns that contrast between monocot (Poales*) and eudicot† orders
| Ion concentration (mm) |
||||
|---|---|---|---|---|
| Element | Epidermis | Mesophyll | Bundle sheath | References |
| Poales | ||||
| Ca | 27·5 ± 5·0 (15–37) | 4·0 ± 0·8 (2–6) | 3·2 ± 0·5 (2–5) | Malone et al., 1989, 1991; Dietz et al., 1992b; Fricke et al., 1994a, b, c, 1996; Brune et al., 1995; Koroleva et al., 2000 |
| Na (2 mm) | 31 ± 12·8 (1–51) | 18 ± 3·1 (3–29) | 17 ± 1·8 (5–19) | |
| K | 211 ± 18·8 (169–249) | 258 ± 11·8 (216–299) | 185 ± 23·8 (180–225) | |
| Mg | 5 ± 1·5 (2–10) | 17·1 ± 4·3 (12–28) | N/A | |
| S | 0·8 | 2·4 | N/A | |
| P | 3·8 ± 1·8 (0–10) | 54·3 ± 8·4 (25–75·5) | 28 | |
| Cl | 106 ± 20 (61·8–160) | 26 ± 7 (16–40) | 34 | |
| NO3 | 161 ± 36 (55–220) | 151 ± 46 (47–226) | 160 | |
| Mn | High | Undetectable | Undetectable | |
| Ni (100 µm) | 0·0021 ± 0·0006 | 0·0094 ± 0·0013 | N/A | |
| Cd (100 µm) | 0·0303 ± 0·0057 | 0·0423 ± 0·0106 | 0·040 ± 0·0077 | |
| Malate | 160 ± 31 | 30 ± 14·1 | 32 ± 17·2 | |
| Eudicots | ||||
| Ca | 10·1 ± 8·2 (0–45) | 68 ± 14 (15–88) | 5·2 ± 2·6 (∼2–9·6) | Mesjasz-Przybylowicz et al., 1994, 2001a, b; Küpper et al., 1999, 2000, 2001; Zhao et al., 2000; Ager et al., 2002, 2003; Bidwell et al., 2004, Epimashko et al., 2004; Fernando et al., 2006; Kerton et al., 2009 |
| Na | 15 | 5 | 14 | |
| K | 106 ± 34 (40–154) | 86 ± 25 (10–120) | 128 ± 22 (75–180) | |
| Mg | 25 | 8 | N/A | |
| S | 20 | 30 | N/A | |
| P | 60·2 ± 20·9 (20–101) | 20·2 ± 8·5 (0–42) | 47 ± 15 (20–80) | |
| Cl | 60·6 ± 10·4 (31–82) | 11·6 ± 1·4 (5–21) | N/A | |
| NO3 | n.d. | n.d. | N/A | |
| Mn | Undetectable | High | Undetectable | |
| Ni (100 µm) | 185 ± 36 (154–213) | 59 ± 12 (25–82) | 26 | |
| Cd (100 µm) | 0·0502 ± 0·010 | 0·0202 ± 0·008 | 0·0252 ± 0·009 | |
| Malate | N/A | 30·9 ± 2·3 (midday) | N/A | |
* Poales includes barley and wheat, with data presented for older leaves, ≥4 d after full expansion.
† Eudicots include tomato, tobacco, arabidopsis, poplar, coriander and Mesambranthemum with Ni data presented for the Ni hyperaccumulators Berkheya coddii, Hybanthus floribundus and Senecio anomalochrous.
Data are presented as mean ± standard error (n = 5–16 reports for each ion) for all reports under their standard growth conditions (concentration range among all species shown in brackets).
N/A, data was not available.