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. 2009 Sep 11;212(19):3132–3141. doi: 10.1242/jeb.031179

Fig. 1.

Fig. 1.

Effect of reduced O2 levels on D. melanogaster metabolic rate (measured as CO2 production). The metabolic response to hypoxia data are from metabolic rates determined at 28 different O2 tensions measured in six independent groups of flies. Data are means ± s.e.m. (A) metabolic rates at O2 tensions ranging from normoxia to 0 kPa. The asterisk indicates when metabolic rate is first significantly reduced compared with normoxia, and the open symbols are the metabolic rate of control groups not exposed to hypoxia. (B) The lower range of the same data plotted at higher resolution. The two lines are the average change in metabolic rate for O2 tensions between 0.1 and 0.6 kPa, and 0.7 and 3.1 kPa. The equation describing the relationship between relative metabolic rate and O2 tension in extreme hypoxia is: MR=0.75x+0.04, r2=0.94; and for less extreme hypoxia MR=0.16x+0.4, r2=0.83, with x as the PO2. (C) Recovery of fly metabolic rate after exposure to anoxia. (D) The RQ (respiratory quotient) and relative metabolic rate of flies progressively exposed to O2 tensions of 1.2, 0.8, 0.4, 0.2 kPa. Open symbols are the relative metabolic rate and RQ of flies maintained in normoxic conditions. Data are from five groups of flies exposed to hypoxia and three control groups.