Copper (Cu) and cadmium (Cd) are ordinary heavy metals. Unreasonable development and utilization of these heavy metals will cause severe pollution to the soils and consequently bring damage to human health. Therefore, recovering soils polluted by heavy metals is crucial. An indoor pot experiment was carried out involving seven treatments, namely, low-concentration Cu stress (Cu1), high-concentration Cu stress (Cu2), low-concentration Cd stress (Cd1), high-concentration Cd stress (Cd2), low-concentration Cu–Cd combined stress (Cu1Cd1), and high-concentration Cu–Cd combined stress (Cu2Cd2), and an uncontaminated soil as a control. Results demonstrated that the net photosynthetic rate and chlorophyll content are approximately 8.36–72.51% and 7.22–36.50%, respectively, lower under the Cu, Cd, and Cu–Cd combined stresses than under the control. The net photosynthetic rates are higher under Cu2 and Cd2 than under Cu1 and Cd1; by contrast, the net photosynthetic rate of leaves is lower under Cu2Cd2 than under Cu1Cd1. The net photosynthesis rate of Cinnamomum camphora is significantly positively correlated with superoxide dismutase activity but is significantly negatively correlated with the total chlorophyll, malondialdehyde, soluble sugar, and proline contents. Young Cinnamomum camphora grows well under Cu, Cd, and Cu–Cd combined stresses and is applicable in ecologically restoring heavy metal–contaminated soils.

The formation of a common mycorrhizal network (CMN) between roots of different plant species enables nutrient transfers from one plant to another and their coexistence. However, almost all studies on nutrient transfers between CMN-connected plants have separately, but not simultaneously, been demonstrated under the same experimentation. Both conspecific and heterospecific seedlings of Cinnamomum camphora, Bidens pilosa, and Broussonetia papyrifera native to a karst habitat in southwest China were concurrently grown in a growth microcosm that had seven hollowed compartments (six around one in the center) being covered by 35.0-μm and/or 0.45-μm nylon mesh. The Ci. camphora in the central compartment was supplied with or without Glomus etunicatum and ¹⁵N to track N transfers between CMN-connected conspecific and heterospecific seedlings. The results showed as follows: significant greater nitrogen accumulations, biomass productions, ¹⁵N content, % Nₜᵣₐₙₛfₑᵣ, and the Nₜᵣₐₙₛfₑᵣ amount between receiver plant species ranked as Br. papyrifera≈Bi. pilosa > Ci. camphora under both M⁺ and M⁻, and as under M⁺ than under M⁻ for Ci. camphora but not for both Bi. Pilosa and Br. papyrifera; the CMN transferred more nitrogen (¹⁵N content, % Nₜᵣₐₙₛfₑᵣ, and Nₜᵣₐₙₛfₑᵣ amount) from the donor Ci. camphora to the heterospecific Br. papyrifera and Bi. pilosa, with a lower percentage of nitrogen derived from transfer (%NDFT). These findings suggest that the CMN may potentially regulate the nitrogen transfer from a donor plant to individual heterospecific receiver plants, where the ratio of nitrogen derived from transfer depends on the biomass strength of the individual plants.