Physiological effects of mercury-contaminated Oxisols on common bean and oat

• Published in: Environmental science and pollution research international 2021-03, Vol.28 (9), p.11279-11288
• Main Authors: de Lima, Francielle Roberta Dias, Barbosa, Alice Pita, Vasques, Isabela Cristina Filardi, Oliveira, Jakeline Rosa, Silva, Aline Oliveira, Martins, Gabriel Caixeta, Engelhardt, Mateus Moreira, Pereira, Polyana, dos Reis, Rayner Hugo Cassa Louzada, Guilherme, Luiz Roberto Guimarães, Marques, João José
• Format: Article
• Language: English
• Subjects: Acclimation; Acclimatization; Acrudox; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Avena; Avena sativa; Beans; Bioavailability; Chemical properties; clay; Clay soils; Cultivation; Damage; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; French beans; Grain cultivation; Hapludox; Heavy metals; Mercuric chloride; Mercury; Mercury (metal); Mercury - analysis; Mercury compounds; Nutrient deficiency; Nutritional status; oats; Organic matter; Oxidative stress; Phaseolus; Phaseolus vulgaris; Photosynthesis; Physiological effects; Physiology; Plant growth; Pollutants; Research Article; Soil; Soil chemistry; Soil contamination; Soil Pollutants - analysis; Soil pollution; Soil properties; Sorption; species; staple foods; Toxicity; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-020-11286-x

The heavy metal mercury (Hg) is one of the most complex and toxic pollutants. When present in soils, it may impair plant growth, but the intensity of damage depends on the physical-chemical properties of the soil such as pH, clay, and organic matter content, which in turn affects Hg sorption and bioavailability. Understanding Hg potential damage to staple food crops is of paramount relevance. Here, we evaluated the physiological effects of Hg in Phaseolus vulgaris (common bean) and Avena sativa (oat) cultivated in two Oxisols with contrasting properties: Rhodic Acrudox (RA) and Typic Hapludox (TH). We performed four independent experiments (one per species/soil combination) that lasted 30 days each. Treatments were composed by HgCl 2 concentrations in soils (0 to 80 mg kg −1 Hg). At the end of the experiment, we determined the impact of Hg on photosynthesis, nutritional status, and oxidative stress. Cultivation in TH contaminated with Hg resulted in oxidative stress in common bean and decreased photosynthesis/P accumulation in oat. No deleterious effects on physiological variables were detected in both species when cultivated in the RA soil. In general, we conclude that the lower Hg sorption in the TH soil resulted in toxicity-like responses, while acclimation-like responses were observed in plants cultivated in RA, reinforcing soil physical-chemical properties as key features driving Hg toxicity in Oxisols. Graphical abstract