Aroclor 1221 was found to cause a significant inhibition of the respiration rate at concentrations above 10−7 M. When Chlorella were immersed in the same Warburg-Buck medium to which no glucose had been added, Aroclor 1221 caused a stimulation of the respiration rate at concentrations above 10−5 M. There appeared to be little effect on photosynthesis in Chlorella when Aroclor 1221 was present even at concentrations as high as 10−3 M. In contrast, oxygen evolution from isolated spinach chloroplasts using potassium ferricyanide as the electron acceptor was inhibited by Aroclor 1221.
Lorsque Chlorella est immergé dans ce même milieu de Warburg-Buck mais sans addition de glucose, l'Aroclor 1221 stimule le taux de respiration aux concentrations supérieures à 10−5 M. Même à des concentrations aussi élevées que 10−3 M, l'Aroclor 1221 semble avoir peu d'effets sur la photosynthèse chez Chlorella. D'autre part, l'Aroclor 1221 inhibe l'évolution d'oxygène à partir de chloroplastes isolés d'épinard utilisant le ferricyanure de potassium comme accepteur d'électrons.