Du Laing Gijs, Van Ryckegem Gunther, Tack Filip M G, Verloo Marc G
Laboratory for Analytical Chemistry and Applied Ecochemistry, Department of Applied Analytical and Physical Chemistry, Ghent University, Coupure Links 653, B-9000 Gent, Belgium. gijs@
Chemosphere. 2006 Jun;63(11):1815-23. doi: 10.1016/j.chemosphere.2005.10.034. Epub 2005 Dec 5.
Metal contents of decomposing leaf blades, leaf sheaths and stems of common reed (Phragmites australis) were monitored by a litter bag method on the sediment of an intertidal brackish marsh in the Scheldt estuary (The Netherlands). On monthly intervals, two litter bags were retrieved from the marsh during 9 months for both leaf blades and sheaths and during 16 months for stems. All samples were dried, weighed and analysed for ash and Cd, Cu, Cr, Ni, Pb and Zn contents. Most concentrations increased considerably during the decomposition. Generally, also a very important net metal inflow into the litter bags could be observed. The inflow was highest for leaf blades. High correlations between ash contents and metal concentrations for leaf blades suggest that the increase of leaf blade metal contents can be due to physicochemical sorption of dissolved metals and an important infiltration of mud particles, which were not removed by rinsing the leaf blades with distilled water preceding the analyses. For stems, smaller amounts of inflowing ash and even outflowing ash amounts were found, which suggests that inflow of inorganic particles is not the major factor determining metal accumulation by stems on medium term. Ergosterol concentrations in stem tissue however proved to be correlated with metal contents, which suggests a significant role of fungal litter colonizers in metal accumulation. For leaf sheaths, the effects of physicochemical sorption, infiltration of mud particles and incorporation by microbial litter colonizers do not seem to be as pronounced as for stems and leaf blades.
采用垃圾袋法，对荷兰斯海尔德河口潮间带咸淡水沼泽沉积物上的芦苇（Phragmites australis）叶片、叶鞘和茎的分解过程中的金属含量进行了监测。在9个月内，每月从沼泽中取出两个垃圾袋用于叶片和叶鞘的监测，在16个月内用于茎的监测。所有样品均进行干燥、称重，并分析灰分以及镉、铜、铬、镍、铅和锌的含量。在分解过程中，大多数金属浓度显著增加。一般来说，还能观察到大量金属净流入垃圾袋。叶片的金属流入量最高。叶片灰分含量与金属浓度之间的高度相关性表明，叶片金属含量的增加可能是由于溶解金属的物理化学吸附以及泥颗粒的大量渗入，而在分析前用蒸馏水冲洗叶片并不能去除这些泥颗粒。对于茎，发现流入的灰分较少，甚至有灰分流出，这表明无机颗粒的流入不是决定茎在中期积累金属的主要因素。然而，茎组织中的麦角甾醇浓度被证明与金属含量相关，这表明真菌对凋落物的定殖在金属积累中起着重要作用。对于叶鞘，物理化学吸附、泥颗粒渗入和微生物对凋落物的定殖作用似乎不如茎和叶片明显。
