[Oxygen and temperature effects on the fatty acid composition in sycamore cells (Acer pseudoplatanus L.) (author's...

Temperature and oxygen effects on the degree of unsaturation of membrane fatty acids have been investigated with sycamore cells in suspension culture. Sycamore cells were incubated with [14C]acetate at temperature varying from 15 to 25 degrees C and at O2 concentration from 12.5 to 305 muM. It was found that: (i) no significant difference was observed in the distribution of radioactivity between oleate and linoleate with different temperatures; (ii) in marked contrast, the aeration conditions during growth of plant cell cultures affected the fatty acid pattern of the total lipids: by maintaining the oxygen concentration below 60 muM, the molar proportion of oleate increased dramatically whereas that of the linoleate decreased. Under these conditions, the aeration of the culture medium (250 muM) induced a rapid transformation of oleate to linoleate. These results cast further doubt on the importance of the temperature on the degree of unsaturation of the fatty acids in sycamore cells, but confirmed evidence that the formation of unsurated fatty acids by plant cells was indeed controlled by the oxygen concentration in solution.