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Root exudates (REs) of Scirpus triqueter were extracted from the rhizosphere soil in this study. The components in the REs were identified by GC-MS. Many organic acids, such as hexadecanoic acid, pentadecanoic acid, vanillic acid, octadecanoic acid, citric acid, succinic acid, glutaric acid, and so on, were found. Batch simulated experiments were conducted to evaluate the impacts of different organic acids, such as citric acid, artificial root exudates (ARE), succinic acid, and glutaric acid in REs of S. triqueter on desorption of pyrene (PYR) and lead (Pb) in co-contaminated wetland soils. The desorption amount of PYR and Pb increased with the rise in concentrations of organic acids in the range of 0-50 g·L(-1), within shaking time of 2-24 h. The desorption effects of PYR and Pb in soils with various organic acids treatments decreased in the following order: citric acid > ARE > succinic acid > glutaric acid. The desorption rate of PYR and Pb was higher in co-contaminated soil than in single pollution soil. The impacts of organic acids in REs of S. triqueter on bioavailability of PYR and Pb suggested that organic acids enhanced the bioavailability of PYR and Pb in wetland soil, and the bioavailability effects of organic acids generally followed the same order as that of desorption effects.

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Due to the severe degradation of wetland ecosystems in China, great efforts, such as the reconstruction of forested wetlands, have been devoted to restore the damaged and degraded wetlands to support species diversity and ecosystem services. However, less attention has been given to the diversity and ecological significance of prokaryotes of the domain Archaea compared with prokaryotes of the domain Bacteria during the reconstruction of forested wetlands. Here, the effects of introduced woody plants (Taxodium distichum and Alnus trabeculosa) on the archaeal community in a freshwater wetland in the Yangtze estuary were investigated. The results showed that Thaumarchaeota obviously predominated at three studied sites in the freshwater wetland, the relative abundance of which decreased with increasing depth, ranging from 93.9% (0–10 cm) to 1.9% (30–40 cm) in mudflats, from 100% (0–10 cm) to 64.8% (30–40 cm) in T. distichum sediment and from 100% (0–10 cm) to 66.7% (40–50 cm) in A. trabeculosa sediment. The abundances of the archaeal amoA gene in woody plant sediments, ranging from 3.27 × 107 to 2.45 × 108 copies g−1 dry soil, were significantly higher than those in bare mudflat, ranging from 9.23 × 106 to 1.35 × 107 copies g−1 dry soil. The archaeal community, which was significantly affected by pH, microbial carbon and SO42− contents according to a canonical correspondence analysis, was significantly altered by plants and soil depth (p < 0.05). These results indicated that the introduction of woody plants stimulates the proliferation of Thaumarchaeota, especially ammonia‐oxidizing archaea, which could be important contributors to the N cycle in forested wetland ecosystems. Copyright © 2017 John Wiley & Sons, Ltd.