Cost assessment of the production of pyrrolizidine alkaloids in ragwort (Senecio jacobaea L.).

Costs of pyrrolizidine alkaloid (Pa) production in vegetative ragwort (Senecio jacobaea) were examined under conditions in which plant growth was limited by light, nitrogen and phosphorus. Measurable costs of Pa production were demonstrated under light-limiting conditions. Plants with higher Pa concentrations grew more slowly than those with lower Pa concentration. Under nitrogen- and phosphorus-limited conditions no trade-off between Pa production and growth was observed.