Variable | Value | Units | Description |
---|---|---|---|
w 0 | 3.2 | g | (Initial value) Initial water content of fruit |
s 0 | 0.5 | g | (Initial value) Initial dry weight of fruit |
P f0 | 2 | bar | (Initial value) Initial turgor pressure of fruit |
a p | 0.066 | – | Area of phloem membrane as fraction of fruit surface area |
a x | 0.066 | – | Area of xylem membrane as fraction of fruit surface area |
D w | 1 | g cm−3 | Density of water |
D s | 1.6 | g cm−3 | Density of dry matter |
H f | 0.996 | – | Relative humidity of air spaces in fruit |
K m | 0.08 | - | Michaelis constant for active transport |
L x | 0.00972 | g cm−2
bar−1 h−1 |
Conductivity of xylem membrane for water transport |
L p | 0.00972 | g cm−2
bar−1 h−1 |
Conductivity of phloem membrane for water transport |
p s | 0.0027 | g cm−2
h−1 |
Permeability of phloem membrane for sugar diffusion |
Q 10 | 2.03 | – | Q10 for maintenance respiration |
q g | 0.21 | – | Growth respiration coefficient |
q m,293 | 0.000131 | h−1 | Maintenance respiration coefficient |
R | 83 | cm3 bar mol−1 K−1 | Gas constant |
ν m | (Eq. 29) | g h−1 | Maximal rate of active sucrose uptake |
φ | (Eq. 28) | bar−1 h−1 | Cell wall extensibility (Lockhart) |
Y | 2 | bar | Threshold pressure (Lockhart) |
Z | (Eq. 27) | – | Proportion of dry weight which is soluble sugars |
ρ | (Eq. 32) | cm h−1 | Permeation coefficient of fruit surface to water vapour |
σ p | 0.9 | – | Reflection coefficient of membrane to sugar |
γ
η |
5.2076 0.6424 |
Parameters relating fruit area (cm2) to fresh weight (g) | |
M W | 18 | – | Molecular weight of water |
M S | 342.3 | – | Molecular weight of sucrose |
π po | 12.53 | bar | Osmotic pressure of other solutes in phloem |
π fo | 6.5 | bar | Osmotic pressure of other solutes in fruit |
L p* | (Eq. 30) | g h−1 bar−1 | Conductance of pedicel phloem |
L x* | (Eq. 31) | g h−1 bar−1 | Conductance of pedicel xylem |
ε | 153 | bar | Fruit elasticity |
r w | 0.6 | – | g water produced when 1g dry weight respires |
Where values vary through the season, they are calculated from the equation numbers given.