Analytical solutions for the CO
2 concentration profile
CA (
z, t) and CO
2 mass transfer coefficient
kL within the assimilation cell phase of the crop leaf in the net photosynthesis process were obtained by the concept of “rate of process” in the engineering science.
To solve the CO
2 mass transfer problem of the crop leaf in net photosynthesis, CO
2-H
2O equilibrium at the assimilation-aerenchyma tissue interface within the crop leaf, Henry's Law, was introduced and the net photosynthetic reaction was approximated by a pseudo-1st order irreversible form.
Simultaneously, in order to estimate quantitatively
kL and the over-all gas phase CO
2 mass transfer coefficient
kG from the practical observed results of the net photosynthetic rate
RA, the graphical method and its procedure were proposed, using the results of
RA for “rice” presented by Yabuki (1992). The summary is as follows:
1) CO
2 mass transfer of a crop leaf in the photosynthesis process is a gas absorption-reaction. It is also a diffusion phenomenon in a gas-liquid binary system and the mechanism of CO
2 absorption may be represented schematically by a “two-film penetration diffusion model”.
2) Analytical solutions and the graphical method are available for evaluation of
kL and
kG from
RA observed in the field. These basic analytical procedures for gas absorption engineering are useful to obtain the correlation of the net photosynthesis reaction rate constant
k1 with
RA and CO
2 mass transfer coefficients.
3)
k1 is a primary characteristic parameter to evaluate the net photosynthetic ability of the crop. The over-all assimilation cell phase CO
2 mass transfer coefficients,
KL,
kL, and
kG depend on
k1. Therefore, to estimate a valid
RA or an appropriate net photosynthetic ability of the crop leaf, CO
2 mass transfer coefficients correlated with
k1 must be used.
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