Symbol | Description | Units |
---|---|---|
A sat | light-saturated rate of photosynthesis at ambient Ca | μmol m−2 s−1 |
R dark | respiration rate at zero irradiance | μmol m−2 s−1 |
Q sat | Light saturation point determined as the Q value for which assimilation is 90% of Asat | μmol m−2 s−1 |
Q comp | Light compensation point determined as the Q value for which the rate of photosynthesis exactly matches the rate of respiration | μmol m−2 s−1 |
α | apparent maximum quantum efficiency | mol mol−1 |
C a | CO2 concentration in the air outside the leaf | μmol mol−1 |
C i | CO2 concentration in intercellular air spaces | μmol mol−1 |
C c | CO2 concentration in the chloroplast | μmol mol−1 |
Γ* | chloroplastic CO2 compensation point | μmol mol−1 |
C i * | intercellular CO2 compensation point in the absence of day respiration | μmol mol−1 |
R d * | rate of mitochondrial respiration in the light | μmol m−2 s−1 |
E N | instantaneous photosynthetic nitrogen use efficiency | μmol mol−1 s−1 |
L s | relative stomatal (plus boundary layer) limitation to photosynthesis | % |
L m | relative mesophyll limitations to photosynthesis | % |
g s | stomatal (plus boundary layer) conductance to CO2 diffusion | mol m−2 s−1 |
g m | Mesophyll transfer conductance to CO2 diffusion | mol m−2 s−1 bar−1 |
V cmax | in vivo maximum rate of ribulose-1,5-bis phosphate (RuBP) carboxylase-oxygenase (Rubisco) carboxylation | μmol CO2 m−2 s−1 |
J max | electron transport driving regeneration of RuBP | μmol electrons m−2 s−1 |
A max | the rate of photosynthesis near saturating Ci (800 μmol mol−1) | μmol CO2 m−2 s−1 |
N a | foliage nitrogen concentration on an area basis | mmol m−2 |
M | Leaf area to mass ratio | m2 kg−1 |
VPD | Leaf-to-air vapour pressure deficit | kPa |