Metallicolous (M) and non-metallicolous (NM) Peganum harmala were compared for Pb tolerance and accumulation, oxidative stress markers, antioxidant capacities, thiols, and organic acids.

M and NM plants were equally tolerant to Pb in the nutrient solution, but M plants accumulated and tolerated more Pb in roots and shoots.

M plants showed slightly higher (<1.2-fold) antioxidant capacities and slightly lower (>0.8-fold) levels of oxidative stress markers under Pb exposure.

20">The quantitatively most pronounced differences between M and NM plants were the Pb-induced increases of protein thiol (1.5-fold higher in M) and citrate (2-fold higher in M).