Morphology, ecology, and contaminant removal efficiency of eight wetland plants with differing root systems

Abstract

The objective of this study was to test the hypothesis that fibrous-root plants and rhizomatic-root plants are characterized by different root morphologies, root growth and distribution, and contaminant removal capabilities. Four fibrous-root and four rhizomatic-root wetland plants were studied in mono-cultured microcosms which received wastewater. Fibrous-root plants had significantly greater (P \ 0.05) small-size root (diameter B 1 mm) biomass and a larger (P \ 0.05) root surface area per plant than the rhizomatic-root plants and exhibited accelerated growth in both shoots and roots compared to the rhizomatic-root plants. Fibrous-root plants developed the majority of their root biomass increment within a shallower gravel medium than the rhizomatic-root plants. All plants demonstrated fast root biomass growth from July to September. The wetland microcosms planted with fibrous-root plants showed significantly higher (P \ 0.05) ammonium-nitrogen (NH 4 -N) and nitrate-nitrogen (NO 3 -N) removal rates from July to December than those planted with the rhizomatic-root plants. These results suggest that root characteristics of wetland plants, which are related to their shoot and root growth, root distribution, and decontamination ability, can be used in the selection of wetland plants with a higher contaminant removal capacity and in the construction of a multi-species wetland plant community.

Plant growth and nutrient removal in constructed monoculture and mixed wetlands related to stubble attributes

“…Previous studies have indicated that plant growth and biomass were tightly correlated with NH 4 -N removal (Cheng et al, 2009b). The present study also supports this trend; data show that wetland plant growth and biomass were correlated with NH 4 -N, TN, and SRP removal, but especially with NH 4 -N removal (Table 2).…”

“…However, it remains unclear how these nutrient removal differences occur between plants with comparable size and growth form (Brisson & Chazarenc, 2009). Nutrient removal ability of wetland plants is reported to be correlated with biomass (Tanner, 1996), growth speed and growth rhythm (Cheng et al, 2009a), and root morphology and distribution (Sorrell et al, 2000;Lorenzena et al, 2001;Kyambadde et al, 2004;Amon et al, 2007;Cheng et al, 2009b). However, results are still very inconsistent and little generalization has been made to help guide species selection (Brisson & Chazarenc, 2009;Vymazal & Kröpfelová, 2009).…”

Performance of a system of natural wetlands in leachate of a posttreatment landfill

“…The removal of nutrients has a close relationship with the plant's growth (Karathanasis et al 2003;Preussler et al 2007;Cheng et al 2009;Liang et al 2011), biomass The results show that E. crassipes (Table 1; Fig. 6) was the species with the largest area of coverage in the system during the period of the study.…”

Interactive effects of NH4+ concentration and O2 availability on growth, morphology, and mineral allocation of hybrid Napier grass (Pennisetum purpureum×P. americanum cv. Pakchong1)

“…However, the hybrid Napier grass seemed to adapt well to grow under low O 2 that the plant growth rates were not significant difference from the plants grown on the normoxic conditions. This ability of the hybrid Napier grass to acclimate to low O 2 might be obtained from its parent, P. purpureum because the plant inhabits in water saturated soil for most of the year (Cheng et al, 2009). Likewise, several species of emergent plants inhabiting wetlands where O 2 is commonly low and NH 4 + is the major N-source for plant growth could tolerate high NH 4 + concentrations compared with submerged species which were sensitive to high NH 4 + (Cao et al, 2007(Cao et al, , 2009.…”