QUANTITATIVE CHANGES OF THE LIPID AND FATTY-ACID COMPOSITION OF LEAVES OF ALEURITES MONTANA AS A CONSEQUENCE OF GROWTH UNDER 700 PPM CO2 INTHE ATMOSPHERE

Leaf lipids of Aleurites plants that were cultivated for 5 months in a ir containing 700 ppm CO2, were compared to those of control plants cu ltivated at 350 ppm CO2. The content of ether soluble lipids referred to dry matter is the same in CO2- and control plants. The comparison o f lipids analyzed as the pigments chlorophyll and carotenoids, phospho lipids and glycolipids shows that the ratio of phospholipids and glyco lipids is slightly shifted in favor of phospholipids in CO2-plants. Th us, within the group of phospholipids, phosphatidylglycerol and phosph atidylinositol occur in higher concentrations in CO2-plants. Although the differences in the lipid content appear moderate in CO2- and contr ol plants, it is the saturation degree of fatty acids that differs sub stantially. The fatty acids of CO2-plants contain according to the hig her phospholipid content approx. 5% more saturated fatty acids. Steari c acid is three-fold increased. Whereas in the phospholipid fraction s aturated fatty acids comprise one half of all fatty acids, the unsatur ated fatty acids make up for 80 to 90% in the glycolipid fraction. In CO2-plants not only in the phospholipid fraction but also in the glyco lipid fraction saturated fatty acids occur in a higher portion. This m eans that not only in the cell membrane of CO2-plants but also in the thylakoid membrane the fluidity is decreased. Also in the wax-fraction long-chained carbonic acids with 20-26 carbon atoms occur. As the por tion of these carbonic acids is twice as high in CO2-plants, it is con cluded that a stronger formation of the wax layers exists in CO2-plant s. By means of Western blotting and by the use of lipid and carotenoid antisera the binding of lipids onto proteins of photosystem II and ph otosystem I was analyzed. It is seen that besides the major amount of lipids which build up the thylakoid membrane, some lipids are also bou nd to membrane peptides. Whereas monogalactolipid is bound to the LHCP -complex peptides, to the OEC(1)-peptide and the 43 and 47 kDa chlorop hyll binding peptides, the anionic lipids sulfoquinovosyldiglyceride a nd phosphatidylglycerol and digalactolipid are bound to the core pepti des of PS II and PS I. beta-carotene and the xanthophylls were found t o be bound to the core peptides and beta-carotene and violaxanthin wer e also bound to the light-harvesting pigment complex.