Cadmium Uptake in Plants as Influenced by Selenium Uptake and Sulphate Availability

With cadmium uptake by plants posing a risk to plants and consumers alike, strategies to reduce metal uptake are desirable. One strategy may be to apply selenium (as selenate) to the growth medium. I hypothesized selenate would yield greater lignification, with a higher proportion of cadmium bound to root cell walls. Consequently, higher selenium in plants would result in greater tolerance to cadmium. Additionally, since selenate is taken up in place of sulphate, providing the plants with high sulphate would inhibit uptake and translocation of selenium, mitigating selenate’s benefits of reducing cadmium uptake and translocation. Experimental results did not support these hypotheses. Selenate did not affect lignification, nor yield lower cadmium uptake and translocation. Rather, shoot selenium and cadmium concentrations were positively correlated. Thus, the safety of consuming plants from where cadmium concentrations are elevated appears unlikely to be improved by applying selenate, and potential for harm may increase