Phytoextraction of Au: Uptake, accumulation and cellular distribution in Medicago sativa and Brassica juncea
Phytoextraction of Au: Uptake, accumulation and cellular distribution in Medicago sativa and Brassica juncea
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DOI：
10.1016/j.cej.2009.10.019
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发表时间：
2010-01-15
影响因子：
15.1
通讯作者：
Harris, Andrew T.
中科院分区：
文献类型：
--
作者：
Bali, Roza;Siegele, Rainer;Harris, Andrew T.
研究了金属浓度、溶液pH值和暴露时间对已知金属植物芥菜（BJ）和紫花苜蓿（MS）中Au的植物提取（即用维管植物分离）的影响。金属吸收推断使用电感耦合等离子体发射光谱（ICP-OES）和体内定位和分布使用质子诱导的X射线发射光谱（μ-PIXE）。MS根积累的最大值为287 mg Au g（-1）（干生物量），BJ根积累的最大值为227 mg Au g-1（干生物量），当暴露于10，000 ppm的KAuCl 4水溶液时。发现在较高的底物浓度（40- 10，000 ppm Au）下，MS比BJ积累相对更大量的Au，而发现BJ在较低浓度（5-20 ppm Au）下是更好的Au积累者。一般来说，MS显示随着Au底物浓度和暴露时间的增加，Au吸收增加，而对于BJ，在较高浓度（100- 10，000 ppm）下暴露48 h后观察到最大吸收，然后在较长暴露时间下降低。的吸收比（UR），定义为Au浓度在植物组织中的浓度在基板上的比例，增加浓度和曝光时间，MS根曝光72小时后，最大值为995。在BJ从根到地上部的金属转运随着底物浓度的增加而增加，但是在地上部，金属吸收从24到48 h增加，然后在72 h下降，表明已经达到一定的阈值水平，然后金属被排除出细胞，可能通过韧皮部到Au溶液。利用mu-PIXE测量的植物组织的元素分布图显示，Au存在于整个样品中，范围从表皮和皮层，最大浓度发生在中央中柱内。该结果提示木质部负载。这些结果共同表明，分离Au使用维管植物应用于采矿（植物采矿）和修复（植物修复）是可行的技术。(C)2009爱思唯尔有限公司版权所有。
The influence of metal concentration, solution pH and exposure time on the phytoextraction (i.e. separation using vascular plants) of Au was investigated for the known metallophytes Brassica juncea (BJ) and Medicago sativa (MS). Metal uptake was inferred using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) and in vivo localisation and distribution using proton induced X-ray emission spectroscopy (mu-PIXE). MS roots accumulated a maximum of 287 mg Au g(-1) (dry biomass) and BJ roots a maximum of 227 mg Au g-1 (dry biomass), both when exposed to a 10,000 ppm aqueous solution of KAuCl4. MS was found to accumulate comparatively greater quantities of Au than BJ across higher substrate concentrations (40-10,000 ppm Au) whereas BJ was found to be a better accumulator of Au at lower concentrations (5-20 ppm Au). In general MS showed an increase in Au uptake with an increase in Au substrate concentration and the time exposed, whereas for BJ the maximum uptake was observed after 48 h of exposure at higher concentrations (100-10,000 ppm), and then decreased at longer exposure times. The uptake ratio (UR), defined as the ratio of Au concentration in plant tissues to the concentration in the substrate, increased with increasing concentration and exposure time, to a maximum of 995 for MS roots after 72 h exposure. Metal translocation from roots to shoots in BJ increased with increasing substrate concentration, however in the shoots, metal uptake increased from 24 to 48 h and then decreased at 72 h, indicating some threshold level had been reached and metal was then being excluded from the cells, possibly through the phloem to the Au solution. Elemental distribution maps of plant tissues measured using mu-PIXE, show Au present across the entire sample, ranging from the epidermis and cortex, with the greatest concentration occurring within the central stele. This result is suggestive of xylem loading. These results collectively suggest that the separation of Au using vascular plants for applications in mining (phytomining) and remediation (phytoremediation) are viable technologies. (C) 2009 Elsevier B.V. All rights reserved.