Effects of bisphenol A on key enzymes in cellular respiration of soybean seedling roots

The environmental endocrine disrupter bisphenol A (BPA) is ubiquitous in the environment, with potential toxic effects on plants. Previous studies have found a significant effect of BPA on levels of mineral nutrients in plant roots, but the underlying mechanism remains unknown. To determine how BPA influences root mineral nutrients, the effects of BPA (1.5 mg L(-1) , 3.0 mg L(-1) , 6.0 mg L(-1) , 12.0 mg L(-1) , 24.0 mg L(-1) , 48.0 mg L(-1) , and 96.0 mg L(-1) ) on activities of critical respiratory enzymes (hexokinase, phosphofructokinase, pyruvate kinase, isocitrate dehydrogenase, and cytochrome c oxidase) were investigated in soybean seedling roots. After BPA exposure for 7 d, the low concentrations of BPA increased the activities of critical respiratory enzymes in roots, whereas opposite effects were observed in roots exposed to high concentrations of BPA, and the inhibitory effect was greater for higher BPA concentrations. In addition, evident morphological anomalies and decreases in root lengths and volumes were induced by high concentrations of BPA. Following withdrawal of BPA exposure after 7 d, the activities of respiratory enzymes and visible signs of toxicity recovered, and the extent of recovery depended on the type of enzyme and the BPA concentration. Furthermore, correlation analysis showed that the disturbance by BPA to activities of respiratory enzymes, which led to interference in the energy metabolism in roots, might be an effect mechanism of BPA on mineral element accumulation in plant roots.