Interactive effects of single, binary and trinary trace metals (lead, zinc and copper) on the physiological responses of Kandelia obovata seedlings

• Published in: Environmental geochemistry and health 2019-02, Vol.41 (1), p.135-148
• Main Authors: Shen, Xiaoxue, Li, Ruili, Chai, Minwei, Cheng, Shanshan, Niu, Zhiyuan, Qiu, Guo Yu
• Format: Article
• Language: English
• Subjects: Biocompatibility; Biomass; Conductance; Contaminants; Copper; Copper - toxicity; Correlation analysis; Earth and Environmental Science; Environment; Environmental Chemistry; Environmental Health; Environmental Pollutants - chemistry; Environmental Pollutants - toxicity; Geochemistry; Heavy metals; Interactions; Kandelia obovata; Lead; Lead - toxicity; Leaves; Lipid membranes; Lipid peroxidation; Lipids; Malondialdehyde; Mangroves; Membranes; Metals; Metals, Heavy - chemistry; Metals, Heavy - toxicity; Original Paper; Osmotic stress; Oxidation; Parameters; Peroxidation; Photosynthesis; Photosynthesis - drug effects; Photosynthesis - physiology; Physiological responses; Plant Leaves - drug effects; Plant Leaves - physiology; Proline; Public Health; Resistance; Rhizophoraceae - drug effects; Rhizophoraceae - physiology; Saccharides; Seedlings; Seedlings - drug effects; Seedlings - physiology; Soil Science & Conservation; Stomata; Stomatal conductance; Stress, Physiological; Stresses; Sugar; Synergistic effect; Terrestrial Pollution; Toxicity; Trace metals; Transpiration; Zinc; Zinc - toxicity
• ISSN: 0269-4042; 1573-2983
• DOI: 10.1007/s10653-018-0142-8

Heavy metals are considered important environmental contaminants, and their mixture toxicity on plants has complex mutual interactions. The interactive effects of heavy metals on growth, photosynthetic parameters, lipid peroxidation and compatible osmolytes were studied in Kandelia obovata grown for 5 months in sediment treated with combinations of lead (Pb), zinc (Zn) and copper (Cu). The results showed no significant reduction of biomass under heavy metal stresses, except for decreased root biomass under higher Pb + Cu treatment, indicating high tolerance of K. obovata to heavy metal stress. Only the photosynthetic parameters, including net photosynthetic rate ( P n ), stomatal conductance ( G s ) and transpiration rate ( T r ), decreased with increasing concentration of treatments (except for Pb + Cu and Pb + Zn + Cu). Trinary treatment (Pb + Zn + Cu) increased biomass and the photosynthetic parameters when compared to the external addition of binary metals. In the roots, biomass and soluble sugar content were lower under binary than trinary treatments, indicating that the combination of Zn and Cu exhibited improved effects of alleviating toxicity than each of them alone in Pb-containing combined treatments. In the leaves, Zn-containing combined treatments significantly decreased malondialdehyde (MDA), soluble sugar and proline content in low concentration, while Pb + Cu treatments significantly increased these parameters ( P