Foliar selenium biofortification of broccolini: effects on plant growth and mineral accumulation

Foliar biofortification is one effective way to alleviate the inadequate intake of selenium (Se) of millions of people worldwide. To evaluate the efficacy of foliar Se application in broccolini (a new hybrid crop variety derived from a cross between kalian cabbage and broccoli), three treatments were tested: 0, 0.05% or 0.10% (w/v) sodium selenate, applied at the early flowering stage. Florets were harvested in four sequential harvests, showing that both yield and nutritional composition were better in the early harvests, producing fewer but heavier and nutrient-richer florets. Although no overall effects on biomass were observed, the increase in total Se concentrations was more than 80- and 170-folds in both root and shoot of 0.05% and 0.10% Se, respectively, and by 270- and 600-fold in the florets. Although boiling resulted in > 50% loss of Se, an intake of 100 g of fresh weight boiled broccolini biofortified with 0.05% Se treatment will provide ~590 μg Se day−1. This amount is in excess of the tolerable upper limit for Se intake. Therefore, whilst broccolini is clearly a good Se accumulator with the potential to be biofortified with Se, lower application rates would need to be determined to be used for human food purposes.