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Feng R.,Agro Environmental Protection Institute | Feng R.,Open Key Laboratory of Agro environment and Food Safety of Ministry of Agriculture | Wei C.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Tu S.,Huazhong Agricultural University
Environmental and Experimental Botany | Year: 2013

Selenium (Se), an essential element for animals and humans, has also been found to be beneficial to plants. In some countries around the world, such as China and Egypt, Se deficiency in the diet is a common problem. To counteract this problem, Se compounds have been used to increase the Se content in the edible parts of crops, through foliar sprays or base application of fertilizers. Se has also been shown to counteract various abiotic stresses induced in plants by cold, drought, high light, water, salinity and heavy metals (metalloids) (HMs), but the associated mechanisms are rather complicated and still remain to be fully elucidated. In this paper, we have focused on reviewing the effects of Se on HM-induced stress in plants, with an emphasis on the potential roles of Se compounds (e.g., selenite and selenate) in conferring tolerance against abiotic stresses. Numerous studies have implicated Se in the following mechanisms: the regulation of reactive oxygen species (ROS) and antioxidants, the inhibition of uptake and translocation of HM, changes in the speciation of HM and finally, rebuilding of the cell membrane and chloroplast structures and recovery of the photosynthetic system. In addition, two other mechanisms may be involved along with the established ones described above. Firstly, it may affect by regulating the uptake and redistribution of elements essential in the antioxidative systems or in maintaining the ion balance and structural integrity of the cell. Secondly, it may interfere with electron transport by affecting the assembly of the photosynthesis complexes. Future relevant studies should be increasingly focused on the changes in the cellular distribution of HM, the formation of Se-HM complexes, the substitution of S by the incorporation of Se into Se-Fe clusters and the relationships between Se, Fe, S and lipid peroxidation. © 2012 Elsevier B.V.


Feng R.,Agro Environmental Protection Institute | Feng R.,Open Key Laboratory of Agro environment and Food Safety of Ministry of Agriculture | Wei C.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Tu S.,Huazhong Agricultural University | And 2 more authors.
Plant and Soil | Year: 2013

Aims: Selenium (Se) can be used to detoxify antimony (Sb); however, the associated mechanisms are not fully understood, in particular, the responses of essential elements to co-exposure to Se and Sb. Methods: To resolve the above question, two nested hydroponic experiments based on a two-factor, five-level central composite design, were performed using a conventional indica rice (Fengmeizhan). Results: The results showed that when the Se concentration was fixed at 0. 8 mg L-1, the addition of Sb, even at concentrations as low as 2. 171 mg L-1, could produce damages to this plant and significantly reduce both the aboveground and root biomasses, suggesting a high toxicity of Sb to this plant. However, when the Sb concentration was fixed at 5 mg L-1, Se eliminated the negative effects of Sb on the aboveground growth of paddy-rice but did not noticeably affect the root biomass, suggesting a beneficial role of Se in conferring resistance to Sb toxicity in paddy-rice. Interestingly, when the Se concentration was fixed at 0. 8 mg L-1, the addition of Sb caused a consistent decrease in the Se concentration in the roots but a slight increase in the Se concentration in the aboveground, suggesting a dual effect of Sb on Se uptake. Furthermore, the addition of Sb could counterbalance the negative effects of 0. 8 mg L-1 Se on the uptake of most of the tested essential elements, significantly increased their concentrations in the different tissues of this plant. Conclusions: The Se-mediated alleviation of Sb toxicity could be closely connected with (1) the direct inhibition of Sb uptake; and (2) the uptake regulation of some essential elements, such as calcium (Ca), magnesium (Mg) and potassium (K). This study contributes to the understanding of both the the interactions between Se and Sb and their effects on the uptake of essential elements in paddy-rice. © 2012 Springer Science+Business Media B.V.


Feng R.,Agro Environmental Protection Institute | Feng R.,Open Key Laboratory of Agro environment and Food Safety of Ministry of Agriculture | Wei C.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Tu S.,Huazhong Agricultural University | And 4 more authors.
Biological Trace Element Research | Year: 2013

This study was carried out to investigate the effects of selenium (Se) on the uptake and translocation of cadmium (Cd) and essential elements in paddy rice (Oryza sativa L., Shuangyou 998). Selenium could alleviate/aggravate Cd toxicity in paddy rice, which depended on the dosages of Se and/or Cd. When Cd treatment level was as low as 35.6 μM, ≤12.7 μM Se could inhibit the uptake of Cd in paddy rice and increase the biomass of paddy rice; however, with Cd levels reaching 89-178 μM, the addition of Se resulted in increases in Cd uptake and exacerbated the growth of paddy rice. Cd always inhibited the uptake of Se. Cd alone suppressed the uptake of Ca, Mg, Mn, Cu, and Zn; however, Se reversed the decreases in the concentrations of the said elements, suggesting an element regulation mechanism to relieve Cd toxicity. Without Cd in the solution, low doses of Se increased the biomasses of shoots and roots at the expense of the more or less decreases in the concentrations of Ca, Mg, K, Fe, Mn, Cu, and shoot Zn, indicating an antagonistic effect of Se on these cations. The presence of Cd could also reverse these decreases especially at the highest treatment levels for both Se and Cd, also suggesting an element regulation mechanism responsible for the detoxification of high dosages of Se. Consequently, when Se is used to alleviate Cd toxicity, attention must be paid to the Cd pollution extent and doses of Se supplement. © 2012 Springer Science+Business Media New York.


Guo J.,Agro Environmental Protection Institute | Guo J.,Open Key Laboratory of Agro environment and Food Safety of Ministry of Agriculture | Tang S.,Agro Environmental Protection Institute | Tang S.,Open Key Laboratory of Agro environment and Food Safety of Ministry of Agriculture | And 8 more authors.
World Journal of Microbiology and Biotechnology | Year: 2011

Batch experiments were designed to characterize a multiple metal resistant bacterium Burkholderia sp. D54 isolated from metal contaminated soils in the Dabaoshan Mine in South China, and a follow-up experiment was conducted to investigate the effects of inoculating the isolate on plant growth and metal uptake by Sedum alfredii Hance grown on soils collected from a heavily contaminated paddy field in Daxing County, Guangxi Zhuang Automounous Region, Southwest China. Our experiments showed that strain D54 produced indole acetic acid (IAA), siderophores, 1-aminocyclopropane-1-carboxylate (ACC) deaminase, and solubilizing inorganic phosphate and solubilized insoluble metal bearing minerals. Bacterial inoculation significantly enhanced S. alfredii biomass production, and increased both shoot and root Cd concentration, but induced little variation in root/shoot Pb concentration and shoot Zn concentration. Despite this, the total shoot and root uptake of Cd, Pb and Zn in S. alfredii inoculated with D54 increased greatly compared to the non-inoculated controls. It was concluded that inoculation with strain D54 could help S. alfredii grow better on metal contaminated soils, produce more biomass, and remove more metals from soil, which implies improved efficiency of phytoextraction from metal contaminated soil. The knowledge gained from the present experiments constitutes an important advancement in understanding of the interaction between plant growth-promoting bacteria and hyperaccumulators with regard to plant ability to grow and remove the multiple heavy metals from soils. © 2011 Springer Science+Business Media B.V.

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