Table 1.
Relationships between sap flow and soil moisture status
| Regression | Data set | θwet (g g−1) | Intercept | Slope |
| Fdry on θdry | Sap flow in vivo I | 0.36±0.02 | –0.92±0.22 | 5.06±0.98 a |
| Sap flow in vivo II | 0.51±0.01 | –0.39±0.13 | 2.04±0.38 b | |
| Pressure-induced sap flow | 0.49±0.02 | –0.75±0.27 | 3.60±0.92 ab | |
| Ψwet (MPa) | ||||
| Fdry on Ψdry | Sap flow in vivo I | –0.09±0.03 | 0.91±0.13 | 1.65±0.32 a |
| Sap flow in vivo II | –0.01±0.00 | 0.41±0.03 | 0.93±0.15 a | |
| Pressure-induced sap flow | –0.01±0.00 | 0.53±0.07 | 1.11±0.29 a |
Regression parameters for relationships between the fraction of total sap flow through (Fdry), and soil water content (θdry) or soil water potential (Ψdry) of the dry part of the root system. Data sets from the sap flow measurements in vivo were discriminated (Fig. 2) using a threshold Ψwet of 0.45 g g−1 (Ψsoil of –0.01 MPa), with data set I including plants where θwet was <0.45 g g−1, and data set II including plants where θwet was >0.45 g g−1. Differences in the slopes of the regressions were determined via two-way ANOVA of data set and θdry or Ψdry. Different slopes (where the interaction term was significant at P < 0.05) are indicated by different letters.