四种湿地植物在人工湿地的生长特性研究

研究了表面流人工湿地中香根草(Vetiveria zizanioides)、风车草(Cyperus flabelliformis)、芦苇(Phrogmites australis)和水鬼蕉(Hymenocallis littoralis)4种植物的根生物量和生长量、根系分布、地上部分的生长情况.风车草、香根草和水鬼蕉根系及地上部分的生长节律相似,9月或10月前生长较快,以后生长减慢甚至停止;芦苇则不同,7月以前生长缓慢,以后生长加速,冬季也保持较快的生长.全年根生长量和根生物量以水鬼蕉最大,显著高于其它植物(P<0.01),香根草最小,显著低于其它3种植物(P<0.01).香根草的根系垂直向下生长,分布较深,而其它3种植物的根系主要分布在浅层土壤中.风车草分株最多,叶面积指数最大.香根草叶面积指数最小.结果表明,在构建多种植物人工湿地群落时,可以考虑将芦苇与大多数湿地植物搭配以保证湿地全年保持较好的净化效果;水鬼蕉可以作为底层植物,和风车草等生长早、植株较高的植物构建多种湿地群落.

Growth Characteristics of Four Species in Surface-flow Constructed Wetlands

The root and shoot growth, root biomass, and root distribution of four species, such as Cyperus flabelliformis, Hymenocallis littoralis, Phragmites australis, and Vetiveria zizanioides, were studied in a surface-flow constructed wetland. The results showed that root and shoot growth pattern were similar among C. flabelliformis, V. zizanioides, and H. littoralis, with a fast growth stage before September or October, and a slow growth stage during the following months, while P. australis was very different, with slow growth of root and shoot before July, and rapid growth maintained throughout winter. H. littoralis exhibited significantly faster root growth and significantly larger root biomass than other species (P<0.01), while V. zizanioides showed significantly slower root growth and a significantly smaller root biomass than other species (P<0.01). Roots of V. zizanioides generally grew vertically, while the roots of the other species were predominantly distributed in the shallow layer of the substrate. C. flabelliformis produced the most tillers, and had the highest leaf area index (LAI), while V. zizanioides showed the smallest LAI. The results suggest that P. australis could be planted with other wetland species to achieve high decontamination rates in treatment wetlands during the autumn and winter months. Results also suggest that H. littoralis, a lower stratum plant, could be paired with tall and early growing species like C. flabelliformis as a beneficial component of the poly-cultivated wetland community.