Table II.

Free His content of T. goesingense tissues exposed to 50 μm Ni for 7 d

ShootRootXylem Sap
nmol g−1fresh biomass μmol L−1
T. goesingense
 Control136 ± 37 (4)742 ± 188 (4)7.4 ± 3 (4)
 Nickel-treated107 ± 62 (5)68 ± 30 (7)18.2 ± 9 (6)
T. arvense
 Control73 ± 16 (4)43 ± 9 (3)57 ± 31 (8)
 Nickel-treatedn.a.n.a.n.a.

His was measured by HPLC as the phenylthiocarbamyl amino acid derivative with methionine sulfoxide as the internal standard. n.a., Not available. Data are the means ± sd of between three and eight independent plant samples (nos. in parentheses represent n).