Resistance comparison of one-year old seedlings of Cappadocian Maple (Acer cappadocicum) and European ash (Fraxinus excelsior) under soil contaminated by lead

Identifying tree species candidate for phytoremediation is very important. However, its prerequisite is conducting comprehensive studies on tree species and evaluation of the plants’ potential. The current research surveyed resistance of two native species of Hyrcanian forest Acer cappadocicum and Fraxinus excelsior at seedling stage. In this regard, one-year old seedlings of both species were grown under different concentrations of lead including 0, 100, 200, 300,400, and 500 milligram lead per kilogram soil during a growth season. During a growth season photosynthetic indexes such as gas exchange, net photosynthesis rate, stomatal conductance, transpiration rate, and substomatal CO2 concentration as well as growth and biomass allocation were studied. The results showed that the presence of lead as a heavy metal led to decline of photosynthesis performance of both species but the inhibitory effects of Pb was less in seedlings of ash. Height and diameter growth as well as seedling biomass of both species were decreased by negative effects of lead but there was no considerable difference between two species. Our finding showed that under the experimental condition, there was no significant difference between resistances of two native species to lead contaminated soil but for making a better decision, further studies are necessary with stronger contamination and for a longer period.