Selenium and sulfur increase sulfur uptake and regulate glucosinolate metabolism in Brassica oleracea.

摘要

Selenium (Se) in soils can result in increased uptake of sulfur (S) and a reduction in glucosinolates in Brassica species. Rapid cycling B. oleracea plants were grown hydroponically in nutrient solutions with Se treatments delivered as sodium selenate at concentrations of 0.0, 0.5, 0.75, 1.0 and 1.5 ppm. Elevated S treatments of 37 ppm sulfate and 37 ppm sulfate/0.75 ppm selenate were incorporated to compare with Se treatments. Se concentration in the nutrient solution was positively correlated with Se and S uptake in the plants. The S concentration of plants exposed to Se was equal to or greater than the S concentration of plants exposed to elevated S in the nutrient solution. In spite of higher S concentrations, there was a decrease in production of 5 of the 7 glucosinolates analysed in Se-enriched plants. Plants in elevated S treatments had higher glucosinolate production than Se treated plants. These results suggest that Se either upregulates or prevents the down-regulation of S uptake in B. oleracea. In addition, the presence of Se within the plant seems to have a negative impact on the production of certain glucosinolates despite adequate availability of S.