Abstract: The oxygen consumption of mitochondria isolated from the chilled (4℃, 24 hr.) corn shoots was increased, while their oxidative phosphorylative efficiency (ADP/O) and respiratory control ratio (RCR) were obviously lowered. Electron micrograph showed that after chilitreatment the mitochondria in the corn shoots were turned into swollen state. Concomitantly, their sensitivity to cyanide inhibition of α-ketoglutarate oxidation was increased and the CN-resistant pathway was almost inactivated.