Physiological responses of Cupressus arizonica and Platycladus orientalis one-year-old seedlings in soil polluted with lead

The use of woody plants for phytoremediation is so valuable but before that studying on their mechanism and resistance potential of different species is necessary. In the current research, we surveyed resistance potential of two conifer species such as Cupressus arizonica and Platycladus orientalis in response to lead contamination. In this regard, one-year old seedlings of both species were grown under different concentrations of lead such as 0, 100, 200, 300,400 and 500 lead milligram per soil kilogram during a growth season and the end of the experiment time some gas exchange, physiological and growth parameters were studied on the all treatments. Statistical analysis showed that photosynthesis and physiological parameters negatively and significantly were affected by the lead contamination but the weak of the plant metabolism didn’t led to seedling mortality. The negative effects of lead contamination on growth and seedling biomass of C. arizonica was less than P. orientalis that the result showed more resistance of the species. Finally it can be concluded that each species has different mechanism in response to lead contamination but C. arizonica is more resistant in compare to C. arizonica. Surely comprehensive research is necessary for make a final decision.