This study presents a mathematical model, which expresses the absorbance of a photosynthetic sample as a non-linear polynomial of selected reference absorbance. The non-linearity is explained by inhomogeneities of a product of pigment concentration and light path length in the sample. The quadratic term of the polynomial reflects the extent of inhomogeneities, and the cubic term is related to deviation of the product distribution from a symmetric one. The model was tested by measurements of suspension of unstacked tobacco thylakoid membranes of different chlorophyll concentrations in cuvettes of different thicknesses. The absorbance was calculated from the diffuse transmittance and reflectance of sample, illuminated by perpendicular collimated light. The evaluated quantity was a sensitivity defined as the relative difference between the sample absorbance and the reference absorbance to the reference absorbance. The non-linearity of sample absorbance was demonstrated by a characteristic deviation of the sensitivity spectrum from a constant value. The absorbance non-linearity decreased on an increase of the product of pigment concentration and cuvette thickness. The model suggests that the sieve and detour effects influence the absorbance in a similar way. The model may be of interest in modeling of leaf or canopy optics including light absorption and scattering.

Department of Biophysics Faculty of Science Centre of the Region Haná for Biotechnological and Agricultural Research Palacký University Šlechtiltelů 27 783 71 Olomouc Czech Republic

See more in PubMed

Plant Cell Physiol. 2009 Apr;50(4):684-97 PubMed

Arch Biochem Biophys. 1959 Oct;84:428-41 PubMed

Photochem Photobiol Sci. 2006 Aug;5(8):735-40 PubMed

Arch Biochem Biophys. 1969 Dec;135(1):97-108 PubMed

Photosynth Res. 1994 Apr;40(1):67-74 PubMed

Arch Biochem Biophys. 1962 Aug;98:274-85 PubMed

Biochim Biophys Acta. 1954 Dec;15(4):461-70 PubMed

Spectrochim Acta A Mol Biomol Spectrosc. 2006 Jun;64(3):722-35 PubMed

Biochim Biophys Acta. 1956 Jan;19(1):1-12 PubMed

Appl Opt. 1987 Feb 1;26(3):514-23 PubMed

EMBO J. 2009 Oct 7;28(19):3052-63 PubMed

Plant Cell Environ. 2011 Dec;34(12):2047-59 PubMed

J Photochem Photobiol B. 2000 Nov;58(2-3):123-9 PubMed

Tree Physiol. 1990 Dec;7(1_2_3_4):115-124 PubMed

Photosynth Res. 2013 Dec;118(3):277-95 PubMed

Annu Rev Plant Biol. 2013;64:351-75 PubMed

From leaf to multiscale models of photosynthesis: applications and challenges for crop improvement

Light quality, oxygenic photosynthesis and more