1. Polymer-coated manganese fertilizer and its combination with lime reduces cadmium accumulation in brown rice (Oryza sativa L.)
- Author
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Changfeng Ding, Taolin Zhang, Hua Zhang, Naijia Guo, Gaoxiang Huang, Muhammad Kamran, Mingjun Ding, Xingxiang Wang, and Zhigao Zhou
- Subjects
Environmental Engineering ,Polymers ,Health, Toxicology and Mutagenesis ,0211 other engineering and technologies ,chemistry.chemical_element ,02 engineering and technology ,Manganese ,010501 environmental sciences ,engineering.material ,complex mixtures ,01 natural sciences ,Soil ,Soil pH ,Environmental Chemistry ,Soil Pollutants ,Fertilizers ,Waste Management and Disposal ,0105 earth and related environmental sciences ,Lime ,021110 strategic, defence & security studies ,Cadmium ,Oryza sativa ,food and beverages ,Oryza ,Oxides ,Calcium Compounds ,Pollution ,Bioavailability ,Horticulture ,chemistry ,engineering ,Brown rice ,Fertilizer - Abstract
Manganese (Mn) has the potential to reduce cadmium (Cd) uptake by rice; however, the efficiency depends on its soil availability. Therefore, this study designed a slow-release Mn fertilizer by employing a polyacrylate coating. Pot trials were conducted to study the effects of coated-Mn and uncoated-Mn alone or in combination with lime on the dynamics of soil dissolved-Mn and available Cd, and the transportation of Mn and Cd within rice. The results showed that coated-Mn declined the release of Mn until the 7th day of application; however, it consistently supplied more dissolved-Mn than uncoated-Mn. As a result, coated-Mn induced a greater Cd reduction (45.8%) in brown rice than uncoated-Mn (9.7%). The total Cd of rice and its proportion in brown rice were greatly reduced by coated-Mn, indicating the inhibition of root uptake and interior transport of Cd. Additionally, lime addition prominently increased the soil pH and decreased the CaCl2-extractable Cd (90.1-93.9%). However, since lime reduced the soil dissolved-Mn, downregulated the OsHMA3 expression and upregulated the OsNramp5 expression, brown rice Cd was reduced by only 43.0%. The combined addition of lime and coated-Mn alleviated the liming effect on soil Mn and gene expression in roots, thereby reducing brown rice Cd by 71.5%.
- Published
- 2021