Table II.
Calculating sieve tube-specific conductivity, k
Calculations of k for both species are made from mean values of each of the parameters below, following Equation 1. k relates turgor pressure drop, Δp, to translocation velocity, U, according to Δp = μUL/k, where μ is sap viscosity and L is translocation distance (Thompson, 2006). stderr, Standard error.
| Variable (Eq. 1) | Value ± stderr (N)
|
|
|---|---|---|
| Arabidopsis Stem Phloem | Tobacco Petiole Phloem | |
| r (μm) | 2.0 ± 0.1 (7) | 5.5 ± 0.2 (16) |
| l (μm) | 107 ± 7 (13) | 122 ± 13 (11) |
| rp (μm) | 0.26 ± 0.01 (7)a | 0.35 ± 0.01 (3)a |
| lp (μm) | 1.0 ± 0.1 (14) | 1.2 ± 0.1 (19) |
| Np | 52 ± 6 (7)a | 108 ± 8 (3)a |
| k (μm2) | 0.28 | 0.45 |
a
These data were derived from images of aniline-blue stained callose (Fig. 6).