Table I. Effects of chemical treatments on xylem vulnerability to cavitation.
Fagus stems were perfused with the solutions indicated. Following perfusion with NaPO4 at pH 10, some stems were then perfused (arrows) with Tris-HCl at pH 10 containing or not 10 mm of CaCl2. Vulnerability curves were then established and the slope and P50 parameters were scored. Data are means (±se) of three to four samples. Two ANOVA analyses were performed to compare two data sets, the one bearing Roman letters and the other bearing Greek letters. Data sharing different letters are significantly different according to a Tukey's HSD test (P < 0.05).
| Perfused Solutions | Slope | P50 |
| MPa | ||
| Control | −63.0a, α (±7.8) | −3.09a, α (±0.03) |
| Water | −66.4a, α (±8.5) | −3.11a, α (±0.06) |
| NaPO4, pH 4 | −74.5a, α (±7.0) | −2.99ab, α (±0.13) |
| NaPO4, pH 10 | −110.0c (±26.5) | −2.03d (±0.08) |
| EGTA | −74.9a (±16.7) | −2.58bc (±0.14) |
| Oxalic acid, pH 2 | −106.9bc (± 9.4) | −2.33cd (±0.13) |
| Oxalic acid, pH 5 | −84.9ab (±11.9) | −2.76abc (± 0.19) |
| Tris-HCl, pH 6 | −69.2α (±6.8) | −3.06α (±0.01) |
| Tris-HCl, pH 8 | −59.2α (±8.7) | −3.00α (±0.02) |
| CaCl2 10 mm | −72.7α (±27.5) | −3.03α (±0.11) |
| NaPO4, pH 10 → Tris-HCl, pH 10 | −74.6α (±11.9) | −2.26β (±0.38) |
| NaPO4, pH 10 → Tris-HCl, pH 10 + CaCl2 | −83.5α (±27.8) | −3.06α (± 0.14) |