Ethane light-induced formation

Figure 4. A Light-induced formation of ethane and ethylene over 60 min with isolated spinach chloroplasts in the presence of 1 fxM oxyfluorfen and 1 fxM oxyfluorfen combined with 1 /mM DCMU (diuron). B Decrease of the Hill reaction (oxygen evolution system H2O potassium ferricyanide) during incubation of isolated chloroplasts in the light with 1 /mM oxyfluorfen present (12, 31),...

Figure 3. A,B Changes of chlorophyll and carotenoid content of the microalga Scenedesmus acutus under the influence of oxyfluorfen (1 /jM). Curve A indicates alleviation of oxyfluorfen activity when 1 /xM DCMU (diuron) is given simultaneously. C Light-induced ethane formation during treatment of the cells with 1 /xM oxyfluorfen over 24 h (12),...

The characteristic feature of a chain initiation step is formation of radicals from nonradical compounds. In the case of chlorination of ethane, chain initiation is by thermal or light-induced homolysis of the Cl—Cl bond to give two chlorine radicals. 

The peroxidative reactions were mediated and sustained by Cu(II) ions in the light. Table IV shows that fatty acids with at least 2 double bonds are necessary for hydrocarbon formation. As Anacystis lacks those fatty acids, no peroxidative volatile hydrocarbons were produced. Spirulina exclusively contains CO-6 fatty acids as endogenous polyunsaturated fatty acids and evolved Cs hydrocarbons only. The third species, Anabaena, whose thylakoids contain co-3 and Co-6 polyunsaturated fatty acids formed C2 and C5 hydrocarbons simultaneously. We conclude that co-3 polyunsaturated fatty acids are the source of ethane and ethylene and that the CO-6 polyunsaturated fatty acids are the source of pentane and pentene in herbicide-induced peroxidation reactions. Furthermore, we obtained evidence that the propane measured with Bumilleriopsis after an 18-h treatment with either 10 >iM oxyfluorfen or 50 jxM Cu(II) originates from a CO-4 polyunsaturated fatty acid. We have recently isolated and identified this acid as 16 3CO4 (Sandmann, Lambert, B5ger in preparation). 

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