Elevated atmospheric CO2 concentration and diurnal cycle induce changes in lipid composition in Arabidopsis thaliana

Few studies regarding the effects of elevated atmospheric CO2 concentrations on plant lipid metabolism have been carried out. Here, the effects of elevated CO2 concentration on lipid composition in mature seeds and in leaves during the diurnal cycle of Arabidopsis thaliana were investigated. Plants were grown in controlled climate chambers at elevated (800 ppm) and ambient CO2 concentrations. Lipids were extracted and characterized using thin layer chromatography (TLC) and gas liquid chromatography. The fatty acid profile of total leaf lipids showed large diurnal variations. However, the elevated CO2 concentration did not induce any significant differences in the diurnal pattern compared with the ambient concentration. The major chloroplast lipids monogalactosyldiacylglycerol (MGDG) and phosphatidylglycerol (PG) were decreased at elevated CO2 in favour of phosphatidylcholine (PC) and phosphatidylethanolamine (PE). Elevated CO2 produced a 25% lower ratio of 16:1trans to 16:0 in PG compared with the ambient concentration. With good nutrient supply, growth at elevated CO2 did not significantly affect single seed weight, total seed mass, oil yield per seed, or the fatty acid profile of the seeds. This study has shown that elevated CO2 induced changes in leaf lipid composition in A. thaliana, whereas seed lipids were unaffected.