Abstract: The effects of cadmium (Cd) on the reactive oxygen productions and genome DNA polymorphism changes in roots of Phaseolus aureus Roxb. cv. VC3762 (Cdsensitive species) and Vicia sativa L. cv. 333/A (Cdresistant species) seedlings were investigated using hydroponic solution culture. The results showed that Cd stress decreased the genomic template stability and induced the changes of the genome DNA polymorphism in the root tips of the two species, manifesting the variation of band intensity, loss of normal bands, and appearance of new bands. Meanwhile, Cd stress inhibited the root growth and increased the production of O₂^-· and the accumulation of H₂O₂ in the roots. The root length of the two species under Cd stress was negatively correlated with the production of O₂^-·, accumulation of H₂O₂, and genome DNA polymorphism in root tip tissues, and the genome DNA polymorphism was positively correlated with the accumulation of H₂O₂ under Cd stress.

Key words: methyl halides, emission fluxes, natural emission, salt marsh, coastal zone.