Scientists from the Institute of Applied Ecology (IAE) of the Chinese Academy of Sciences (CAS), along with their collaborators, reported that the inter-specific difference exerted a significant effect on the sensitivity and response of tree species to ozone (O₃), heavy metal (cadmium, Cd) and the combination of the two pollutants.

The results showed that elevated O₃ exposure did not affect growth, net photosynthetic rate and oxidative injury of C. ovata seedlings. No interactive effect between Cd and O₃ on physiological processes of C. ovata was found. By contrast, their previous study in Ecotoxicology and Environmental Safety showed that the same O₃ exposure decreased significantly growth and inhibited net photosynthetic rate of poplar. Soil Cd addition increased the susceptibility of plants to O₃ and significant interaction between O₃ and Cd was observed in physiological parameters of poplar.

These results implied that inter-specific difference might play a vital role in affecting urban environmental quality and attribute to the different physiological or molecular mechanisms of tree species exposed to the abiotic multi-stresses.

These findings may be referred when selecting plant species for urban afforestation and soil ecological restoration in heavy industrial cities with high ozone-polluted areas.

Their research paper "Tropospheric ozone and cadmium do not have interactive effects on growth, photosynthesis and mineral nutrients of Catalpa ovata seedlings in the urban areas of Northeast China" was published in Science of the Total Environment.

This research is financially supported by the National Natural Science Foundation of China.