Silene vulgaris, roots

Sharma Shanti S, Schat H, Vooijs R, van Heerwaarden LM. 1999. Combination toxicology of copper, zinc, and cadmium in binary mixtures concentration-dependent antagonistic, nonadditive, and synergistic effects on root growth in Silene vulgaris. Environ Toxicol Chem 18 348-355. 

Enzyme induction is an indirect effect of metal toxicity. In consequence, it only appears after in-vivo metal application. Increase in capacity in the presence of toxic concentrations of metals implies that the enzyme involved is insensitive to or well masked from direct metal action. In Silene cucubalus POD and to a lesser extent ICDH were shown to be very tolerant to zinc, copper and cadmium applied in-vitro (Mathys, 1975). MDH extracted from roots of both copper tolerant and non-tolerant clones of Agrostis stolonifera was found to be insensitive in-vitro to copper concentrations up to 180 im. However, in the literature, conflicting results are reported about the effects of in-vitro and in-vivo application of metals on enzymes. In Phaseolus vulgaris, GDH was inhibited by cadmium in-vitro, while an induction was found after in-vivo application of a toxic dose of the same metal (Weigel and Jager, 1980b). 

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