Table 3.
Effect of salinity (control vs. 100 mm NaCl) on total C, N, amino acids, soluble sugars and the sum of equivalent anion (Cl−, SO42−, NO3− and PO43−) and equivalent cation (Na+, K+, Ca2+, Mg2+ and NH4+) concentrations in phloem sap and xylem sap exuded from excised roots and from the middle part of stems of Nerium oleander plant after 30 d exposure to 100 mm NaCl as affected by ammonium or nitrate as nitrogen source
| NH4+-N |
NO3−-N |
|||
|---|---|---|---|---|
| 0 | 100 | 0 | 100 | |
| Phloem sap | ||||
| Total C (mg mL−1) | 130·8 ± 6·44 | 99·6 ± 8·28 | 121·2 ± 4·76 | 113·4 ± 4·93 |
| Total N (mg mL−1) | 7·06 ± 1·11 | 3·95 ± 1·37 | 4·44 ± 0·68 | 5·22 ± 1·32 |
| C/N ratio | 18·52 | 25·23 | 27·30 | 21·73 |
| Sugar (mg mL−1) | 83·2 ± 5·33 | 75·4 ± 6·12 | 78·6 ± 9·62 | 72·8 ± 12·02 |
| Σ Anion (meq L−1) | 111·1 | 183·1 | 83·2 | 156·4 |
| Σ Cation (meq L−1) | 103·9 | 144·3 | 114·8 | 171·4 |
| Xylem sap root | ||||
| Sugar (mg mL−1) | 1·34 ± 0·77 | 2·92 ± 1·34 | 1·32 ± 0·68 | 2·14 ± 1·35 |
| Σ Anion (meq L−1) | 13·0 | 67·8 | 13·3 | 56·6 |
| Σ Cation (meq L−1) | 10·55 | 78·8 | 19·5 | 67·1 |
| Xylem sap shoot | ||||
| Sugar (mg mL−1) | 1·23 ± 0·97 | 3·04 ± 1·82 | 1·40 ± 1·11 | 2·03 ± 1·58 |
| ΣAnion (meq L−1) | 72·4 | 131·6 | 59·6 | 82·5 |
| Σ Cation (meq L−1) | 70·6 | 169·1 | 90·7 | 114·4 |
Values are means ± s.e. of four replicate plants.