Macrophytes have an important function in constructed phytoremediation
systems through pollutant uptake, release oxygen
and maintenance of habitats for micro-organisms; however, the
quantitative role that the plant plays in wastewater purification is
still a subject (Zhang et al., 2009; Marchand et al., 2010). In this
study, the comparison between the planted and unplanted systems
(i.e., Table 1a: Phase IV, Table 1b: Item A-Phase IVeIV and B-Phase
IVeV) leads to conflicting result regarding the importance of plants
in the phytoremediation process. The lowest percentage removals
of COD (23.4 ± 5.9%), TDS (3.6 ± 1.2%) and Cu (18.5 ± 4.2%) were
observed in the unplanted unit (Fig. 6). A visual assessment of the
plant leaves showed no detrimental effect caused by wastewater
exposure and no anatomical damage was observed on the plant
roots despite the absorbed nutrients with increasing of the yield of
plants (Fig. S-1a and Table 2). Aquatic plants can adapt morphologically
and anatomically to growing in a polluted wastewater
through an internal gas space, called the aerenchyma (Hondulas,
1994). The impurities are translocated from the epidermis to the
vascular bundles and further transported upwards to the plant.