Producing Cd-safe rice grains in moderately and seriously Cd-contaminated paddy soils
| Autor: | Hongping Chen, Fang-Jie Zhao, Peng Wang, Jia-Dong Chang, Peter M. Kopittke |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Environmental Engineering
Health Toxicology and Mutagenesis 0208 environmental biotechnology chemistry.chemical_element Biomass 02 engineering and technology 010501 environmental sciences complex mixtures 01 natural sciences Soil Animal science Soil pH Soil Pollutants Environmental Chemistry Paddy soils 0105 earth and related environmental sciences Cadmium Mitigation methods Chemistry Public Health Environmental and Occupational Health food and beverages Oryza Rice grain General Medicine General Chemistry Contamination Pollution 020801 environmental engineering Soil water Edible Grain |
| Zdroj: | Chemosphere. 267:128893 |
| ISSN: | 0045-6535 |
| DOI: | 10.1016/j.chemosphere.2020.128893 |
| Popis: | Rice grains produced on cadmium (Cd) contaminated paddy soils often exceed the maximum permissible limit. A number of mitigation methods have been proposed to decrease Cd accumulation in rice grain in contaminated acidic soils, including altering water management regimes, liming, and genetic engineering. In the present study, we conducted a pot experiment to compare these methods for their effectiveness at decreasing grain Cd concentrations in both acidic (pH 5.1–5.2) and alkaline (pH 7.5–7.9) paddy soils that varied in the degree of Cd contamination. In moderately Cd-contaminated acidic soils (with Cd concentrations lower than the intervention value of Chinese soil standard, GB15618-2018), any of the three methods was effective, reducing grain Cd concentration by 80–90% to levels below the Chinese maximum permissible limit (0.2 mg/kg). However, in the highly Cd-contaminated soils (with soil Cd concentrations exceeding the intervention value) with elevated concentrations of extractable Cd, although both liming and alternation of the water management regime (continuous flooding) was effective at decreasing grain Cd accumulation, grain Cd concentrations still exceeded the Chinese limit. Genetic engineering of rice, such as knockout of OsNramp5 (encoding the plasma membrane transporter responsible for Cd uptake into root cells) or overexpression of OsHMA3 (encoding a tonoplast Cd transporter sequestering Cd into the vacuoles), produced dramatic decreases (≥90%) in grain Cd concentration. Even in seriously contaminated soils, overexpression of OsHMA3 alone produced grain with Cd concentrations below the Chinese limit, offering a highly effective approach to produce Cd-safe rice especially in seriously Cd-contaminated paddy soils without affecting grain biomass or the concentrations of essential micronutrients. |
| Databáze: | OpenAIRE |
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