Influence of a CO₂-Partial Pressure of 700 PPM on the Lipid and Fatty Acid Composition of Higher Plants

Abstract

The CO₂-content of the atmosphere is steadily increasing (1,2). It is generally assumed that the CO₂-content of air will increase within the next 50 years from now 350 ppm to 700 ppm. In context with this expected atmospheric change it is of interest to know what impact the CO₂-increase will have on growth of higher plants. With Nicotiana tabacum and the Chinese “Tung Oil Tree” Aleurites montana we were able to show that under the influence of the increased CO₂-content 30–40% more biomass is formed (3,4,5). Differences in dependence on the CO₂-content are observed for the chlorophyll and sugar content on the one hand but also with respect to the content of the biomass forming enzyme ribulose 1.5-bisphosphate carboxylase and the energy equivalent-forming coupling factor of photophosphorylation CF₁. Molecular changes are observed in the composition of peptides of photosystem II and photosystem I. Thus, the light-harvesting complex of photosystem II (3,4) is reduced and the same is true for photosystem I (5). The oxygen-evolving-complex (OEC)-peptides are reduced in plants cultivated under increased CO₂ (3,4). In addition the electron transport components (plastoquinone, cytochrome f, plastocyanin, ferredoxin, ferredoxin-NADP-reductase) are reduced under these conditions as shown by rocket-immune-electrophoresis (6).