Effects of methyl mercury on arrays of microtubules and macromolecular synthesis in Daucus carota cultures.

Cell suspension cultures of Daucus carota were exposed to methyl mercury at concentrations between 0 and 6 micrograms/ml for 1, 3, or 24 hr. Microtubule arrays exhibited no detectable disruption (as compared with controls) when treated with 1, 2, and 3 micrograms/ml methyl mercury. Disorganization of microtubules did occur at higher concentrations (4-6 micrograms/ml) in a concentration/time-dependent manner. No recovery of microtubule arrays was evident when cells were placed in methyl mercury-free medium for up to 7 days. Analyses of soluble protein and carbohydrate content, dry weight, and cell viability (reducing capacity) indicate that methyl mercury exposure has inhibitory effects on cell metabolism. The observed disruption of plant cell microtubules, induced by exposure to methyl mercury, may be secondary in response to an initial inhibition of synthetic pathways and membrane perturbations.