Accumulation and histological location of heavy metals in Phragmites australis grown in acid mine drainage contaminated soil with or without citric acid
Accumulation and histological location of heavy metals in Phragmites australis grown in acid mine drainage contaminated soil with or without citric acid
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DOI：
10.1016/j.envexpbot.2014.04.010
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发表时间：
2014-09
影响因子：
5.7
通讯作者：
Lin Guo;D. Ott;T. Cutright
中科院分区：
文献类型：
--
作者：
Lin Guo;D. Ott;T. Cutright
酸性矿山废水(AMD)是一个严重的环境问题。研究了重金属和柠檬酸(CA)对种植在AMD污染田地或土壤中的芦苇体内重金属的积累和组织学变化。结果表明，在重金属含量较高的土壤中，根茎和根茎积累了较多的金属。铁主要储存在铁含量较低的部位的根的外胚层中，而在铁含量较高的部位生长的根中，铁已扩展到内皮层。低铝立地根的外胚层和内胚层中均含有铝，但高铝立地根的中柱中也含有铝。低浓度的CA使Fe进入根髓，高浓度的CA使Fe进入整个根中柱。CA还通过促进铝进入中柱，改变了铝在根中的储存位置。对于根状茎，表皮、皮层和中央圆柱体是储存铁和铝的主要部位。CA增加了根茎维管束周围组织中铁和铝的贮量。根或根茎中的铁或铝浓度越高，染色强度越强。重金属含量的定量数据也支持CA可以提高土壤中重金属的生物有效性，从而促进Fe和Al的积累和转移的假说。一般来说，土壤中添加的CA水平越高，芦苇对金属的吸收越多。
Acid mine drainage (AMD) is a serious environmental issue. This study investigated the heavy metal accumulation and histological alterations caused by heavy metals and citric acid (CA) in reeds grown in AMD contaminated field or spiked soil. The results indicated that the roots and rhizomes accumulated more metals from soil containing higher level of metals. Most of Fe was stored in the exodermis of roots grown in sites that contained less Fe, while Fe had extended to the endodermis of roots grown in sites with higher levels of Fe. Al was found in the exodermis and endodermis of roots collected from sites with lower Al concentrations, but the stele of roots grown in sites with higher level of Al also contained Al. Low level of CA caused Fe enter the pith of roots, while higher level of CA resulted Fe being in the entire stele of roots. CA also altered the Al storage location in roots by enhancing Al entering stele. For rhizomes, the epidermis, cortex and central cylinder were the main sites to store Fe and Al. CA increased the storage of Fe and Al in the tissues around vascular bundles of rhizomes. The higher concentrations of Fe or Al in roots or rhizomes, the stronger intensity of the staining was observed. The quantitative data of heavy metal content also supported the hypothesis that CA can increase the bioavailability of heavy metals in soils and thus enhance the accumulation and translocation of Fe and Al. In general, the higher level of CA added into the soil, the more metals uptake by reeds.