13C/12C Carbon Isotope Fractionation between Atmospheric Carbon Dioxide and Photosynthesis Products in Plant Leaves As Affected by the Spectral Composition of Lighting Environment

We investigate the effects that the spectral composition of radiation that plants are exposed to during their development has on the fractionation of carbon isotopes between atmospheric carbon dioxide and the primary products of photosynthesis in plant tissues. The difference in carbon isotope composition between carbon in air near the leaves and carbon in the leaves varies in the range of 7 to 19 depending on the spectral composition of incident light, with an increase in the red component resulting in enrichment of the leaves with the light isotope 12C. This differences are (i) the measure of isotope fractionation during the vital activity of plants and (ii) the rate of carbon assimilation due to photosynthetic reactions.