In all treatments maximum assimilation rate and stomatal conductance decreased the first day after addition of salt and/or PEG, and thereafter progressively increased throughout the treatment.
For both Boreal and Mediterranean climatic zones, barley ideotypes under future climatic conditions should have a longer reproductive growing period, lower leaf senescence rate, larger radiation use efficiency or maximum assimilation rate, and higher drought tolerance.
We define the surface-specific maximum assimilation rate as: { A m }= A m V1∞−2/3, with V1∞ being the ad libitum asymptotic maximum structural volume.
The normal form of this dependence is something like where F represents food availability, F H is the half-saturation food availability (which is related to search volume), and φ max is the maximum assimilation rate scale (which is related to ingestate handling time).
Considering this behavior, a CO2 concentration value of 950 ppm can be used to represent the CO2 concentration at which maximum assimilation specific rate from a plant type can be obtained.
The light response curves showed the maximum CO2 assimilation rate at 500 μmol photons m-2 s-1 which then decreased with increasing photosynthetic photon flux density (PPFD) in both WT and the DnaJ mutants.
For L. chinensis plants, there were significant effects on maximum gross CO2 assimilation rate (Ag,max) and maximum carboxylation velocity (Vc,max) due to the water treatments.
Previous study divided the physiological condition into four states according to Populus photosynthetic activity from 22°C to 42°C: baseline (22°C, the growth temperature), optimum (31.75°C, temperature producing the maximum net CO2 assimilation rate), 20% inhibition of optimum (38.4°C) and 30% inhibition of optimum (40.5°C) [ 39].
In a previous study, the physiological conditions of poplars at temperatures between 22°C and 42°C were divided into four states based on photosynthetic activity: the baseline (22°C, the growth temperature), optimum (31.75°C, temperature producing the maximum net CO2 assimilation rate), 20% inhibition of optimum (38.4°C), and 30% inhibition of optimum (40.5°C) [ 47].
The central parameters representing photosynthetic capacity, including light-saturated net CO2 assimilation rate (Asat), maximum in vivo carboxylation velocity (Vc,max), and maximum rate of electron transport (Jmax) have been used to assess the effects of global changes on the biosphere, although parameters may be altered under different growth conditions [ 26, 27].
Severe water deficit produced negative effects on light-saturated net CO2 assimilation rate (Asat), stomatal conductance (gs), mesophyll conductance (gm), maximum carboxylation velocity (Vc,max), and maximal efficiency of PSII photochemistry (Fv/ Fm).
