Root structural changes of two remediator plants as the first defective barrier against industrial pollution, and their hyperaccumulation ability.

Abstract

In the present day, plants are increasingly being utilized to safeguard the environment. In this study, we used Salsola crassa M. B. and Suaeda maritima L. Dumort for phytoremediation of water contaminated with heavy metals and simultaneous examination of the effect of industrial pollution on their root structures. After irrigation of a treatment group with wastewater and a control group with fresh water for 3months, we fixed the root parts in the FAA fixator for developmental study, and measured the concentrations of Co, Ni, Zn, As, Cu, and Pb in the roots, shoots, soil, and irrigating water. The plants irrigated with wastewater showed significant accumulation of heavy metals in the roots and some translocation of heavy metals from the roots to the shoots. We also performed an experiment with two 0.3m3 pools to more closely study the feasibility of these plants for filtering water of contaminants, including mineral compounds, and altering its chemical characteristics. In our anatomical studies, the cells of the treatment roots showed irregularities and abnormal appearances in all tissue layers. The diameter and area of the xylem and the size of the cortical parenchyma have increased in the treatment plants of both species, confirmed by Stereolite software. Phytoremediation studies indicated that S. crassa accumulated As, Cu, Zn, Pb, Co, and Ni, and S. maritima accumulated As, Co, Zn, and Cu. S. crassa accumulated more heavy metals in its roots, whereas S. maritima accumulated more in its shoots. The biological oxygen demand and chemical oxygen demand were also significantly reduced in the wastewater passed through pools with S. crassa. Our results indicate that both genera are hyperaccumulators of heavy metals and therefore hold promise for industrial wastewater treatment, especially the absorption of As.