The phytotoxicity of selected mycotoxins on mature, germinatingZea mays embryos.
Mature maize (Zea mays) embryos were exposed to 5, 10 and 25 µg ml(-1) of deoxynivalenol (DON), zearalenone (ZEA), ochratoxin A (OA) and a mixture of zearalenone and deoxynivalenol (ZEA/DON) for 9 days. DON and the ZEA/DON combination were consistently more inhibitory of the measured parameters than either ZEA or OA. Based on the predicted additive values, it would appear that, in combination, ZEA and DON act synergistically to inhibit root and shoot growth. For ZEA alone, a concentration of 5 µg ml(-1) ZEA was generally inhibitory of root and shoot elongation and fresh mass accumulation, while at 10 and 25 µg ml(-1), this toxin had a stimulatory effect on these parameters. For OA, the measured effects on root and shoot growth at 5 and 25 µg ml(-1) were stimulatory, while at 10 µg ml(-1) OA, an inhibitory effect was observed. For all toxins, inhibitory/stimulatory effects were generally more marked for root parameters than for shoot elongation or mass.
McLean
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Department of Physiology, Faculty of Medicine, University of Natal, P.O. Box 17039, 4013, Congella, South Africa, mclean@med.und.ac.