The effect of various uncouplers on the respiration of appendix tissue slices of Sauromatum guttatum Schott (Araceae) at various stages of anthesis

In the presence of glucose, the respiration of appendix tissue slices of the arum lily Sauromatum guttatum Schott is markedly stimulated by the uncouplers 2,4-dinitrophenol, Na-azide and pentachlorophenol after the first day of flowering. There is no appreciable effect on the first flowering-day itself, and only a minor stimulation (if any) at younger stages. These results are interpreted on the basis of the hypothesis that, on the first day of flowering, respiration is of the "uncoupled” type. The relative lack of response to the uncouplers in the young floweringstages is probably due to a rapid turnover of ATP in connection with the spectacular growth of the inflorescence.