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Article: Differences in uptake and translocation of selenate and selenite by the weeping willow and hybrid willow

TitleDifferences in uptake and translocation of selenate and selenite by the weeping willow and hybrid willow
Authors
Issue Date2008
PublisherSpringer. The Journal's web site is located at http://www.springer.com/environment/journal/11356
Citation
Environmental Science And Pollution Research, 2008, v. 15 n. 6, p. 499-508 How to Cite?
AbstractBackground, aim, and scope: Due to its essentiality, deficiency, and toxicity to living organisms and the extensive use in industrial activities, selenium (Se) has become an element of global environmental and health concern. Se removal from contaminated sites using physical, chemical, and engineering techniques is quite complicated and expensive. The goal of this study was to investigate uptake and translocation of Se in willows and to provide quantitative information for field application whether Se phytoremediation is feasible and ecologically safe. Materials and methods: Intact pre-rooted plants of hybrid willows (Salix matsudana Koidz x alba L.) and weeping willows (Salix babylonica L.) were grown hydroponically and treated with selenite or selenate at 24.0±1°C for 144 h. Removal of leaves was also performed as a treatment to quantify the effect of transpiration on translocation and volatilization of Se. At the end of the study, total Se in the hydroponic solution and in different parts of plant tissues was analyzed quantitatively by hydride generation-atomic fluorescence spectrometry. The capacity of willows to assimilate both chemical forms of Se was also evaluated using detached leaves and roots in sealed glass vessels in vivo. Translocation efficiency of Se in both plants was estimated. Results: Significant amounts of the applied selenite and selenate were eliminated from plant growth media by willows during the period of incubation. Both willows showed a significantly higher removal rate for selenate than for selenite (p <0.05). Substantial differences existed in the distribution of both chemical forms of Se in plant materials: lower stems and roots were the major sites for accumulation of selenite and selenate, respectively. Translocation efficiency for selenite was significantly higher than that for selenate in both willow species (p <0.01). Compared to the intact trees, remarkable decrease in the removal rate of both chemical forms of Se was found for willows without any leaves (p <0.01). Volatilization of Se by plant leaves was estimated to be approximately 10% of the total applied selenite or selenate. Significant reduction (>20%) of selenate was observed in the sealed vessel with excised roots of willows, whereas trace amounts of selenite were eliminated from the hydroponic solution in the presence of roots. Detached leaves from neither of them reduced the concentration of selenite or selenate in the solution. Discussion: Due to the significant difference in the removal rate and the distribution of the two chemical forms of Se in plant materials, the conversion of selenate to selenite in hydroponic solution prior to uptake and within plant tissues is unlikely. An independent uptake and translocation mechanisms are likely to exist for each Se chemical species. Uptake of selenate is mediated possibly through an active transport mechanism, whereas that of selenite may possibly depend on plant transpiration. Uptake velocities of selenite are linear (zero-order kinetics), while selenate removal processes obey first-order kinetics. In experiments with detached leaves in closed bottles, the cuticle of leaves was the major obstacle to extract both chemical forms of Se from the hydroponic solution. Phytovolatilization is a biological process playing an important role in Se removal. Conclusions: Although faster removal rates of selenate than selenite from plant growth media were observed by both willow species, selenite in plant materials was more mobile than selenate. Significant decrease in removal rates of both chemical forms of Se was detected for willows without any leaves. Significant differences in extraction, assimilation and transport pathways for selenite and selenate exist in willow trees. Recommendations and perspectives: Phytoremediation of Se is an attractive approach of cleaning up Se contaminated environmental sites. More detailed investigation on the assimilation of Se in plant roots and transport in tissues will provide further biochemical evidence to explain the differences in uptake and translocation mechanisms between selenite and selenate in willows. A relevant phytoremediation scheme can then be designed to clean up Se contaminated sites. Willows show a great potential for uptake, assimilation and translocation of both selenite and selenate. Phytotreatment of Se is potentially an efficient and practical technology for cleaning up contaminated environmental sites. © 2008 Springer-Verlag.
Persistent Identifierhttp://hdl.handle.net/10722/179083
ISSN
2015 Impact Factor: 2.76
2015 SCImago Journal Rankings: 0.886
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorYu, XZen_US
dc.contributor.authorGu, JDen_US
dc.date.accessioned2012-12-19T09:51:50Z-
dc.date.available2012-12-19T09:51:50Z-
dc.date.issued2008en_US
dc.identifier.citationEnvironmental Science And Pollution Research, 2008, v. 15 n. 6, p. 499-508en_US
dc.identifier.issn0944-1344en_US
dc.identifier.urihttp://hdl.handle.net/10722/179083-
dc.description.abstractBackground, aim, and scope: Due to its essentiality, deficiency, and toxicity to living organisms and the extensive use in industrial activities, selenium (Se) has become an element of global environmental and health concern. Se removal from contaminated sites using physical, chemical, and engineering techniques is quite complicated and expensive. The goal of this study was to investigate uptake and translocation of Se in willows and to provide quantitative information for field application whether Se phytoremediation is feasible and ecologically safe. Materials and methods: Intact pre-rooted plants of hybrid willows (Salix matsudana Koidz x alba L.) and weeping willows (Salix babylonica L.) were grown hydroponically and treated with selenite or selenate at 24.0±1°C for 144 h. Removal of leaves was also performed as a treatment to quantify the effect of transpiration on translocation and volatilization of Se. At the end of the study, total Se in the hydroponic solution and in different parts of plant tissues was analyzed quantitatively by hydride generation-atomic fluorescence spectrometry. The capacity of willows to assimilate both chemical forms of Se was also evaluated using detached leaves and roots in sealed glass vessels in vivo. Translocation efficiency of Se in both plants was estimated. Results: Significant amounts of the applied selenite and selenate were eliminated from plant growth media by willows during the period of incubation. Both willows showed a significantly higher removal rate for selenate than for selenite (p <0.05). Substantial differences existed in the distribution of both chemical forms of Se in plant materials: lower stems and roots were the major sites for accumulation of selenite and selenate, respectively. Translocation efficiency for selenite was significantly higher than that for selenate in both willow species (p <0.01). Compared to the intact trees, remarkable decrease in the removal rate of both chemical forms of Se was found for willows without any leaves (p <0.01). Volatilization of Se by plant leaves was estimated to be approximately 10% of the total applied selenite or selenate. Significant reduction (>20%) of selenate was observed in the sealed vessel with excised roots of willows, whereas trace amounts of selenite were eliminated from the hydroponic solution in the presence of roots. Detached leaves from neither of them reduced the concentration of selenite or selenate in the solution. Discussion: Due to the significant difference in the removal rate and the distribution of the two chemical forms of Se in plant materials, the conversion of selenate to selenite in hydroponic solution prior to uptake and within plant tissues is unlikely. An independent uptake and translocation mechanisms are likely to exist for each Se chemical species. Uptake of selenate is mediated possibly through an active transport mechanism, whereas that of selenite may possibly depend on plant transpiration. Uptake velocities of selenite are linear (zero-order kinetics), while selenate removal processes obey first-order kinetics. In experiments with detached leaves in closed bottles, the cuticle of leaves was the major obstacle to extract both chemical forms of Se from the hydroponic solution. Phytovolatilization is a biological process playing an important role in Se removal. Conclusions: Although faster removal rates of selenate than selenite from plant growth media were observed by both willow species, selenite in plant materials was more mobile than selenate. Significant decrease in removal rates of both chemical forms of Se was detected for willows without any leaves. Significant differences in extraction, assimilation and transport pathways for selenite and selenate exist in willow trees. Recommendations and perspectives: Phytoremediation of Se is an attractive approach of cleaning up Se contaminated environmental sites. More detailed investigation on the assimilation of Se in plant roots and transport in tissues will provide further biochemical evidence to explain the differences in uptake and translocation mechanisms between selenite and selenate in willows. A relevant phytoremediation scheme can then be designed to clean up Se contaminated sites. Willows show a great potential for uptake, assimilation and translocation of both selenite and selenate. Phytotreatment of Se is potentially an efficient and practical technology for cleaning up contaminated environmental sites. © 2008 Springer-Verlag.en_US
dc.languageengen_US
dc.publisherSpringer. The Journal's web site is located at http://www.springer.com/environment/journal/11356en_US
dc.relation.ispartofEnvironmental Science and Pollution Researchen_US
dc.subject.meshBiological Transport - Physiologyen_US
dc.subject.meshPlant Leaves - Drug Effects - Metabolismen_US
dc.subject.meshPlant Roots - Drug Effects - Metabolismen_US
dc.subject.meshPlant Transpiration - Drug Effectsen_US
dc.subject.meshSalix - Drug Effects - Metabolismen_US
dc.subject.meshSelenium Compounds - Metabolism - Pharmacologyen_US
dc.subject.meshSodium Selenite - Metabolism - Pharmacologyen_US
dc.titleDifferences in uptake and translocation of selenate and selenite by the weeping willow and hybrid willowen_US
dc.typeArticleen_US
dc.identifier.emailGu, JD: jdgu@hkucc.hku.hken_US
dc.identifier.authorityGu, JD=rp00701en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1007/s11356-008-0036-xen_US
dc.identifier.pmid18719961-
dc.identifier.scopuseid_2-s2.0-51349152638en_US
dc.identifier.hkuros160874-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-51349152638&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume15en_US
dc.identifier.issue6en_US
dc.identifier.spage499en_US
dc.identifier.epage508en_US
dc.identifier.isiWOS:000258898900010-
dc.publisher.placeGermanyen_US
dc.identifier.scopusauthoridYu, XZ=24449490500en_US
dc.identifier.scopusauthoridGu, JD=7403129601en_US

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