Prediction of Rate of CO₂ Assimilation of Leaf Lettuce under Low Light Irradiation during Storage

Abstract

The rate of CO₂ assimilation of leaf lettuce changed with its respiration rate and gas constitution in a storage chamber. The optimum irradiance on the surface of leaf lettuce during storage using low light irradiation can be obtained by the prediction of the rate of CO₂ assimilation. For the above mentioned purpose the following equation were derived.
-kd[C]/dt=0.5(1-f)I([C]-Γ/4.5[C]+10.5Γ)-ae^-bt
where, k: proportional constant (4.87×10^-3mol⋅m^-2) [C]: CO₂ concentration (ppm), t: time (h), f: fraction of light not absorbed by chloroplasts (0.23), I: irradiance (μmol⋅m^-2⋅s^-1), Γ: CO₂ compensation point without respiration (21.5ppm), a, b: parameters (0.308μmol⋅m^-2⋅s^-1, 0.010h^-1). Calculated values of rate of CO₂ assimilation by the equation agreed well with experimental ones at 3.4 and 6.5μmol⋅m^-2⋅s^-1 of irradiance, so it appeared that the assimilation rate could be sufficiently predicted.