ICP-MS analysis of Ni, GUS enzyme activity and GUS staining of T2 transgenic plants containing p (1.0) BjMTP1::GUSPlus.(A) ICP-MS analysis of Ni in T2 transgenic plants containing p (1.0) BjMTP1::GUSPlus after exposure to 50 μM Ni2+ in 0.1× Hoagland's nutrient media. After 48 h exposure plants were transferred to 0.1× Hoagland's without Ni2+ (arrow) and Ni2+ accumulation monitored for a further 48 h. Symbols represent roots (squares), and shoots (triangles). (B) GUS enzyme activity (nmoles of 4-methyl umbelliferone min-1 mg-1 total protein) measured during the same treatment and time frame as in (A). Symbols represent roots (squares), and shoots (triangles) of plants homozygous for the transgene, and roots (circles) and shoots (diamonds) from control plants identified by PCR as null segregants for the transgene. (C) GUS enzyme activity and Ni2+ accumulation, from roots exposed to 50 μM Ni2+ for 48 h (data from A and B). Data represents the average (± SD) of three independent replicate samples for both GUS activity and Ni accumulation. GUS activity visualized by histochemical staining in roots (D), leaves (E) and floral organs (F) from plants exposed to 50 μM Ni2+ for 48 h (roots and floral organs) or 24 h (leaves). a stigma, b anther.