Herbarium X-ray fluorescence screening for nickel, cobalt and manganese hyperaccumulator plants in the flora of Sabah (Malaysia, Borneo Island)

Sabah (Malaysia) on the Island of Borneo has a high plant diversity (>8000 species) occurring on a wide range of soils, including ultramafic soils which are known to host hyperaccumulator plants. In this study a new approach (“Herbarium X-ray Fluorescence Ionomics”) was used to obtain elemental data from herbarium specimens using non-destructive X-ray Fluorescence spectroscopy analysis. In total ~7300 specimens were thus analysed for nickel, cobalt, and manganese concentrations at the Herbarium of the Forest Research Centre (FRC) in Sepilok, Sabah. The measurements led to recording a total of 759 specimens (originating from 17 families in 30 genera and 74 species) as trace element hyperaccumulators, including 28 nickel hyperaccumulator species (in 10 families, 17 genera), 12 cobalt hyperaccumulator species (in 3 families, 7 genera), and 51 manganese hyperaccumulator species (in 12 families, 24 genera). The outcomes of this research demonstrate that X-ray Fluorescence scanning is highly useful approach for hyperaccumulator plant discovery in herbarium collections that has the potential to add vast numbers of hyperaccumulating taxa to the global inventory.