The effect of zinc on sea urchin morphogenesis

Embryos of the sea urchin Lytechinus pictus were incubated for different periods of time in various concentrations of ZnCl2 in artificial sea water at pH 7.0 and 7.8. In general, zinc treatment restricts the development of endoderm and mesenchyme derivatives and zinc may be classified as an animalizing substance. The specificity of the zinc effects is analyzed considering the time during development that 65Zn is taken up by the embryo and the possible effects of zinc on protein synthesis, cell division and cell migration. The possibility that zinc exerts its effect non‐specifically as a toxic substance is explored. The animalizing properties of zinc may be the result of a non‐specific arrest in development at the time when the structures derived from the vegetal half are differentiating.