Effects of organic acids on the photosynthetic and antioxidant properties and accumulations of heavy metals of Melilotus officinalis grown in Cu tailing

• Published in: Environmental science and pollution research international 2016-09, Vol.23 (18), p.17901-17909
• Main Authors: Han, Yulin, Wu, Xue, Gu, Jiguang, Zhao, Jiuzhou, Huang, Suzhen, Yuan, Haiyan, Fu, Jiajia
• Format: Article
• Language: English
• Subjects: Acetic acid; Acetic Acid - pharmacology; Antioxidants; Antioxidants - pharmacology; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Biomass; Citric Acid - pharmacology; Copper; Earth and Environmental Science; Ecotoxicology; Edetic Acid - pharmacology; Environment; Environmental Chemistry; Environmental Health; Environmental impact; Environmental science; Enzymes; Heavy metals; Melilotus - drug effects; Melilotus - growth & development; Melilotus officinalis; Metals; Mine tailings; Mine wastes; Mining; Organic acids; Oxidative stress; Peroxidase - metabolism; Photosynthesis; Photosynthesis - drug effects; Physiology; Phytoremediation; Plant Roots - drug effects; Plant Roots - metabolism; Research Article; Seedlings; Seedlings - drug effects; Seeds; Studies; Superoxide Dismutase - metabolism; Toxicity; Vegetation; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-016-6920-x

The effect of citric acid (CA), acetic acid (Ac), and ethylene diamine tetraacetic acid (EDTA) on the photosynthetic and antioxidant properties and the accumulation of some heavy metals (HMs) of Melilotus officinalis seedling growing in Cu mine tailings for 25 days were studied. Results showed that the formation of photosynthesizing cells of M. officinalis was inhibited by EDTA at 2 mmol/kg. Photosynthetic pigment contents under EDTA of 2 mmol/kg were reduced by 26, 40, and 19 %, respectively, compared to the control. The proline contents in aboveground and underground parts increased as the level of EDTA was enhanced. CA and Ac enhanced the activities of superoxide dismutase (SOD) and peroxidase (POD) in the aboveground parts and EDTA inhibited the activity of POD in the underground parts. The addition of CA promoted significantly the growth of M. officinalis , while the biomass decreased significantly under 2 mmol/kg EDTA. Cu contents in the aboveground parts treated with 0.5 and 2.0 mmol/kg EDTA reached 175.50 and 265.17 μg/g dry weight, respectively. Ac and EDTA treatments promoted Cd to translocate from root to aboveground parts. The result indicated that M. officinalis was a tolerant species of Cu tailing and can be used to remediate Cu contaminated environment, and rationally utilization of organic acids, especially EDTA, in the phytoremediation can improve the growth and metals accumulation of M. officinalis .