Metal regulated transcriptional activation of BjMTP1 by its 983 bp promoter. Five-day-old dark grown seedlings, transformed with p (1.0) BjMTP1::GUSPlus, were exposed to different concentrations of Ni2+ (A), Cd2+ (B) or Zn2+ (C) and both GUS activity (nmol MU/mg protein/min) and K+ leakage (nmoles K+/min/mg dry weight) measured. Each data point represents an average (± SD) of three independent replicate samples. (D) Histochemical GUS staining of seedlings exposed to 25 μM Ni2+ for 48 h (bottom) and unexposed seedlings (top). Insert shows the GUS localization in an individual seedling. Scale bar = 1 cm.