Mn accumulation in a submerged plant Egeria densa (Hydrocharitaceae) is mediated by epiphytic bacteria.
Mn accumulation in a submerged plant Egeria densa (Hydrocharitaceae) is mediated by epiphytic bacteria.
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DOI：
10.1111/pce.12910
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发表时间：
2017-07
期刊：
影响因子：
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通讯作者：
Kousuke Tsuji;T. Asayama;N. Shiraki;S. Inoue;Erina Okuda;Chizuru Hayashi;Kazuma Nishida;H. Hasegawa-H.
中科院分区：
文献类型：
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作者：
Kousuke Tsuji;T. Asayama;N. Shiraki;S. Inoue;Erina Okuda;Chizuru Hayashi;Kazuma Nishida;H. Hasegawa-H.
许多水生植物作为生物吸附剂，从环境中去除和回收金属。为了评估一种被淹没的淡水大型植物Egeria densa的生物吸附活性，我们每月从琵琶湖流域的一个圆形流域收集植物，并分析了这些植物的Mn浓度。这些植物的Mn浓度普遍高于陆生超积累植物，且春季和夏季明显高于秋季。在不同pH水平的水培培养基中培养的植株，无论是否补充锰，其锰浓度都远低于田间收集的植株。采用变压扫描电镜-能量色散x射线分析和白蛋白蓝染色法测定了锰氧化物在叶片上的沉淀。从田间采集的密生藤中分离出几株附生细菌，其中许多菌株，包括酸性菌属、单胞菌属、假单胞菌属和根瘤菌属，均具有锰氧化活性。高锰浓度是由叶面生物膜产生的生物氧化锰介导的。这些发现为研究影响金属在植物体内积累的植物表皮细菌群提供了新的见解，并表明这些水生植物可能在锰的植物提取中有用途。
Many aquatic plants act as biosorbents, removing and recovering metals from the environment. To assess the biosorbent activity of Egeria densa, a submerged freshwater macrophyte, plants were collected monthly from a circular drainage area in Lake Biwa basin and the Mn concentrations of the plants were analysed. Mn concentrations in these plants were generally above those of terrestrial hyperaccumulators, and were markedly higher in spring and summer than in autumn. Mn concentrations were much lower in plants incubated in hydroponic medium at various pH levels with and without Mn supplementation than in field-collected plants. The precipitation of Mn oxides on the leaves was determined by variable pressure scanning electron microscopy-energy dispersive X-ray analysis and Leucoberbelin blue staining. Several strains of epiphytic bacteria were isolated from the field-collected E. densa plants, with many of these strains, including those of the genera Acidovorax, Comamonas, Pseudomonas and Rhizobium, found to have Mn-oxidizing activity. High Mn concentrations in E. densa were mediated by the production of biogenic Mn oxide in biofilms on leaf surfaces. These findings provide new insights into plant epidermal bacterial flora that affect metal accumulation in plants and suggest that these aquatic plants may have use in Mn phytomining.