蚯蚓和基质种类对人工湿地植物根系特征及净化效果的影响

选择4种常见的人工湿地基质(沙、沙+土、有机质+沙、有机质+沙+土),研究加入蚯蚓后不同基质对黄菖蒲最长根长、根体积和基质总孔隙度及其净化CODMn能力的影响。结果表明,不同基质上黄菖蒲的最长根长、根体积存在差异,以有机质+沙基质上黄菖蒲的最长根长、根体积最大,而沙子基质上黄菖蒲的最长根长、根体积最小,两处理间存在显著差异(P<0.01)。加入蚯蚓能增加黄菖蒲的最长根长、根系体积、总孔隙度和CODMn的去除率。相关分析显示,黄菖蒲的最长根长、根体积与总孔隙度呈显著正相关(P<0.01),且根系体积、最长根长与CODMn去除率也呈显著正相关(P<0.01)。

Effect of Earthworms and Substrates on Root Characteristics of Wetland Plant and Purifying Capacity of Constructed Wetland

Earthworms have been introduced to constructed wetlands to help purify the wastewater and used in the restoration of a wetland clogged by pollutants,by both loosening the substrate and converting the organic matter into its dissolved constituents.Earthworms play an important role in constructed wetland,but there is little information about how earthworms affect wetland plant.This study investigated the effect of four common substrates(sand,sand-soil mixture,sand-organic matter mixture,and sand-soil-organic matter mixture) with or without addition of earthworms on the maximum root length and root volume of Iris pseudacorus,the porosity and removing efficiency of CODMn.Results showed that the maximum root length and root volume of Iris pseudacorus planted in the substrate of sand-organic matter mixture were the highest,while those of sand substrate were the lowest,giving significant differences(P<0.01) in the maximum root length and root volume between the two substrate treatments.The addition of earthworms into the substrates increased the maximum root length,root volume,the porosity and CODMn removing efficiency of substrate.Correlation analysis showed that the maximum root length and root volume were significantly(P<0.01) positively correlated with substrate porosity and CODMn removal efficiency.