Backgraund
Extensive research is ongoing looking for the characterisation of programmed cell death (PCD) in plants involving pathogen attack, chemical elicitation and abiotic inducers, but there are still limited reports on the role of heavy metals in PCD induction and little is known about cadmium-triggered signal transduction in plant systems. Contamination of biosphere with heavy metals has hazardous effect on agricultural crops and human health. In animal models, cadmium intoxication occurs through apoptosis appearing by apoptotic phenotype and an oxidative stress is involved in the mechanism of Cd action. The goal of this present work was to investigate if programmed cell death occurs in cadmium-treated tomato suspension cells; to identify some of the biochemical processes contributing to the signal transduction pathway(s) involved in cadmium toxicity; to investigate the role of oxidative stress (hydrogen peroxide), ethylene and lipid-derived signals and to look for similarities between cadmium- and camptothecin-induced cell death.