Insights into cadmium induced physiological and ultra-structural disorders in Juncus effusus L. and its remediation through exogenous citric acid

• Published in: Journal of hazardous materials 2011-02, Vol.186 (1), p.565-574
• Main Authors: Najeeb, Ullah, Jilani, Ghulam, Ali, Shafaqat, Sarwar, Muhammad, Xu, Ling, Zhou, Weijun
• Format: Article
• Language: English
• Subjects: Antioxidants; Applied sciences; Cadmium; Cadmium - metabolism; Cadmium - toxicity; Cd accumulation; chelating agents; Chelating Agents - chemistry; Chemical engineering; Chloroplast; Chloroplasts; Citric acid; Citric Acid - chemistry; Continental surface waters; Damage; EDTA; EDTA (chelating agent); Environmental Pollutants - metabolism; Environmental Pollutants - toxicity; Environmental Restoration and Remediation - methods; Enzyme activity; Exact sciences and technology; growth retardation; Hydrogen-Ion Concentration; Juncus effusus; Microscopy, Electron, Transmission; Natural water pollution; oxidative stress; phytoremediation; Plant growth; plasmolysis; Poaceae - drug effects; Poaceae - growth & development; Poaceae - metabolism; Pollution; Reactors; shoots; shrinkage; starch; Stresses; Toxicity; Ultra-structural modification; Water treatment and pollution; wetland plants; Wetlands
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2010.11.037

This study appraised cadmium (Cd) toxicity stress in wetland plant Juncus effusus, and explored its potential for Cd phytoextraction through chelators (citric acid and EDTA). Cadmium altered morphological and physiological attributes of J. effusus as reflected by growth retardation. Citric acid in the presence of 100μM Cd significantly countered Cd toxicity by improving plant growth. Elevated Cd concentrations reduced translocation factor that was increased under application of both chelators. Citric acid enhanced Cd accumulation, while EDTA reduced its uptake. Cadmium induced oxidative stress modified the antioxidative enzyme activity. Both levels of citric acid (2.5 and 5.0mM) and lower EDTA concentration (2.5mM) helped plants to overcome oxidative stress by enhancing their antioxidative enzyme activities. Cadmium damaged the root cells through cytoplasmic shrinkage and metal deposition. Citric acid restored structure and shape of root cells and eliminated plasmolysis; whereas, EDTA exhibited no positive effect on it. Shoot cells remained unaffected under Cd treatment alone or with citric acid except for chloroplast swelling. Only EDTA promoted starch accumulation in chloroplast reflecting its negative impact on cellular structure. It concludes that Cd and EDTA induce structural and morphological damage in J. effusus; while, citric acid ameliorates Cd toxicity stress.