The effect of lead and copper on some physiological traits in plant species of grass pea (Lathyrus sativus)

Some plant species are tolerant to environmental adverse conditions so that with their functional mechanisms prevent more production of free radicals of oxygen or counter with produced free radicals of oxygen. This study was done to investigate the effect of lead and copper on Lathyrus sativus in contaminated soils with these elements. To evaluate and recognize the study species ability against heavy metals lead and copper an experiment was carried out on Lathyrus sativus cultivar Zanjan in 2009. The experiment was carried out factorially as randomized complete design with four levels of lead Pb (NO3) 2 (0، 200، 400 and 800 mg/kg) and four levels of copper Cu (So4) 2 (0، 150، 300، 450 mg/kg) were used. Although the results suggested the decrease in total chlorophyll content and lipid membrane under the toxicity of lead and copper، the more activity of the enzyme Superoxide dismutase (SOD) along with the increase in the levels of lead and copper in thid species prevented the more production of free radicals of oxygen in the study species، so that a negative coloration was observed between chlorophyll a، b and total chlorophyll and the enzyme superoxide dismutase (SOD). Also the coloration between Malondialdehyde (MDA) which is a means for measuring the lipid per oxidation process، and the enzyme Superoxide dismutase (SOD) was positive that means the increase in this biomarker content which is a sign of more production of oxygen for lipid membrane destruction، was accomplished with the more activity of enzyme Superoxide dismutase (SOD) for more digestion and elimination of destructive oxygen. Also the water condition in leaf tissues (RWC) was not effective by these elements.