Xun Wang1, Nora Fung-Yee Tam2, Shi Fu3, Aray Ametkhan1, Yun Ouyang1, Zhihong Ye4. 1. State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, PR China. 2. Department of Biology and Chemistry, City University of Hong Kong, Hong Kong SAR, PR China State Key Laboratory in Marine Pollution, City University of Hong Kong, Hong Kong SAR, PR China. 3. Fine Arts College, Sichuan Normal University, Chengdu 610110, PR China. 4. State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, PR China lssyzhh@mail.sysu.edu.cn.
Abstract
BACKGROUND AND AIMS: Mercury (Hg) is an extremely toxic pollutant, especially in the form of methylmercury (MeHg), whereas selenium (Se) is an essential trace element in the human diet. This study aimed to ascertain whether addition of Se can produce rice with enriched Se and lowered Hg content when growing in Hg-contaminated paddy fields and, if so, to determine the possible mechanisms behind these effects. METHODS: Two cultivars of rice (Oryza sativa, japonica and indica) were grown in either hydroponic solutions or soil rhizobags with different Se and Hg treatments. Concentrations of total Hg, MeHg and Se were determined in the roots, shoots and brown rice, together with Hg uptake kinetics and Hg bioavailability in the soil. Root anatonmy was also studied. KEY RESULTS: The high Se treatment (5 μg g(-1)) significantly increased brown rice yield by 48 % and total Se content by 2·8-fold, and decreased total Hg and MeHg by 47 and 55 %, respectively, compared with the control treatments. The high Se treatment also markedly reduced 'water-soluble' Hg and MeHg concentrations in the rhizosphere soil, decreased the uptake capacity of Hg by roots and enhanced the development of apoplastic barriers in the root endodermis. CONCLUSIONS: Addition of Se to Hg-contaminated soil can help produce brown rice that is simultaneously enriched in Se and contains less total Hg and MeHg. The lowered accumulation of total Hg and MeHg appears to be the result of reduced bioavailability of Hg and production of MeHg in the rhizosphere, suppression of uptake of Hg into the root cells and an enhancement of the development of apoplastic barriers in the endodermis of the roots.
BACKGROUND AND AIMS: Mercury (Hg) is an extremely toxic pollutant, especially in the form of methylmercury (MeHg), whereas selenium (Se) is an essential trace element in the human diet. This study aimed to ascertain whether addition of Se can produce rice with enriched Se and lowered Hg content when growing in Hg-contaminated paddy fields and, if so, to determine the possible mechanisms behind these effects. METHODS: Two cultivars of rice (Oryza sativa, japonica and indica) were grown in either hydroponic solutions or soil rhizobags with different Se and Hg treatments. Concentrations of total Hg, MeHg and Se were determined in the roots, shoots and brown rice, together with Hg uptake kinetics and Hg bioavailability in the soil. Root anatonmy was also studied. KEY RESULTS: The high Se treatment (5 μg g(-1)) significantly increased brown rice yield by 48 % and total Se content by 2·8-fold, and decreased total Hg and MeHg by 47 and 55 %, respectively, compared with the control treatments. The high Se treatment also markedly reduced 'water-soluble' Hg and MeHg concentrations in the rhizosphere soil, decreased the uptake capacity of Hg by roots and enhanced the development of apoplastic barriers in the root endodermis. CONCLUSIONS: Addition of Se to Hg-contaminated soil can help produce brown rice that is simultaneously enriched in Se and contains less total Hg and MeHg. The lowered accumulation of total Hg and MeHg appears to be the result of reduced bioavailability of Hg and production of MeHg in the rhizosphere, suppression of uptake of Hg into the root cells and an enhancement of the development of apoplastic barriers in the endodermis of the roots.
Authors: Marek Vaculík; Tommy Landberg; Maria Greger; Miroslava Luxová; Miroslava Stoláriková; Alexander Lux Journal: Ann Bot Date: 2012-03-28 Impact factor: 4.357
Authors: Marwa A Ismael; Ali Mohamed Elyamine; Yuan Yuan Zhao; Mohamed G Moussa; Muhammad Shoaib Rana; Javaria Afzal; Muhammad Imran; Xiao Hu Zhao; Cheng Xiao Hu Journal: Int J Mol Sci Date: 2018-07-24 Impact factor: 5.923