Assessing the potential of Khayasenegalensis in phytoremediation of heavy metals under borehole water and tannery effluent irrigation

Khayasenegalensis was planted on soil irrigated with tannery effluent and borehole water for duration of three months. Plant samples were collected after harvest and soil samples were collected before planting and after harvesting. Atomic Absorption Spectroscopy (AAS) was used to determine the concentration of heavy metals in the planting media and plant tissues. The aim was to establish the phytoremediation potential of Khayasenegalensis under these conditions. After harvesting, a noticeable decrease in the concentrations of Cd, Cr, Cu Ni, Pb and Zn in the media was observed from the initial values. The highest levels of Cd (5.53±0.56mg/kg), Cr (13.99±0.82mg/kg), Pb(10.6110.61±0.57mg/kg, Ni (8.33±2.78mg/kg)and Zn(25.72±0.00 mg/kg) accumulation were found in the roots, whereas the highest Cu (7.29±1.80mg/kg) concentrations was observed in the shoot. The roots of Khayasenegalensis were found to be suitable for the phytostabilization heavy metals in both the tannery effluent and borehole water irrigated media. In addition, Cd, Cr, Cu, Ni and Pb mainly accumulated in the Khayasenegalensisroots. The results of translocation factors (TF) and bioconcentration factors (BCF) of Khayasenegalensis for heavy metals revealed that Khayasenegalensis is an excluder plant for Cd, Cr, Pb, Ni and Zn and a potential accumulator plant for Cu serving as an ideal remediation plant for this metal. Furthermore, the increasing heavy metal contents in soil that have been irrigated with tannery effluent resulted in the accumulation of these metals inKhayasenegalensis.

Analysis of metal accumulation and Phytochelatin Synthase (PCS) gene expression in Saccharum spontaneum L. as regards its function for remediation of lead (Pb) contamination

Pollution caused by heavy metals, has become a serious problem. Adverse effects arising from the increased use of heavy metals in a variety of human activities lead to any environmental degradation. Lead (Pb) is one of most common contaminants in the environment and highly toxic. Pb is less mobile, so its compound tends to accumulate in soil and sediments. Definitely, efforts are needed to remove this contaminant in the environment. Saccharum spontaneum L. is a perennial grass which has potential to be used as an accumulator plant to clean up pollutants. The ability of this plant as metal accumulator was tested in this study. S.pontaneum plants were treated using Pb in the concentrations of 0 ppm (control), 100 ppm, 200 ppm, and 300 ppm for 8 weeks. The results showed that there was an increase in the percentage of relative accumulation of Pb in the treated plants. This also indicated that plant roots accumulated more Pb than shoots. Meanwhile, expression of Phytochelatin synthase (PCS) gene increased 1.3-to-3.5-fold inductions in roots by increasing concentration of Pb treatments for 24 h. PCS gene expression showed the higher induction in the roots than in the shoots of S.spontaneum plant under Pb treatments.

Trass Effect as a Source of Silicon on Soil, Hay, Husk and Growth of Rice Plants

Silicon (Si) is one of the important things for rice growth. The importance of Si relates to increased rice yield, increased resistance to disease and resistance to falling. The rice is an accumulator plant of Si which requires Si for its growth. However, the Si in soil is continually decreased therefore the additional Si is needed intothe soil. Trass is one of the natural materials containing Ca and Si, therefore it can be used as a Si fertilizer. This study aims to determine levels of soil Si, straw, husk, and growth in rice. This research consisted of three types of soil, Oxisol, Inceptisol and Vertisol as the main plot and 7 doses of burnt fuel namely 0 (D0); 1.25 (D1); 2.5 (D2); 3.75 (D3); 5 (D4); 7.5 (D5); 10 (D6) g kg-1 of soil as subplots. The treatment which is using in this research is a combination of the two factors and repeated 3 times 63 unit experiments were obtained. The results showed the Trass significant concerning to Si in the husk and Si of the soil. Vertisol gives the highest number of panicles of 27 and Si in the straw of 12.75 mg kg-1.

Antioxidant Responses of Phenolic Compounds and Immobilization of Copper in Imperata cylindrica, a Plant with Potential Use for Bioremediation of Cu Contaminated Environments

This work examined the capability of Imperata cylindrica to respond, tolerate and accumulate Cu when growing at high Cu concentration (300 mg kg−1 of substrate) at different times of exposure (2, 14 and 21 days). The Cu accumulation in plants was examined by atomic absorption spectroscopy (AAS) and Cu localized by Scanning Electron Microscopy-Energy Dispersive X-Ray spectroscopy. Additionally, the phenolic compound identifications and concentrations were determined using liquid chromatography coupled to mass spectrometry. Our results showed that root biomass decreased significantly at high Cu levels, with a greater decrease at 21 days (39.8% less biomass in comparison to control). The root showed 328 mg Cu kg−1 dry weight at 21 days of exposure to Cu, being the tissue that accumulates most of the Cu. Lipid peroxidation was a clear indicator of Cu stress, principally in shoots. The exposure to Cu significantly increased the synthesis of phenolic compounds in shoots of plants exposed 21 days to Cu, where 5-caffeoylquinic acid reached the highest concentrations. Our results support that I. cylindrica is a Cu accumulator plant in root organs with a medium level of accumulation (between 200–600 mg Cu kg−1 biomass), which can tolerate the exposure to high Cu levels by means of increasing the synthesis of phenolic compound in shoots, suggesting a potential use as phytoremediation tool in Cu polluted environments.

The Garden Candytuft (Iberis umbellata L.): At the Crossroad of Copper Accumulation and Glucosinolates

The copper accumulation ability and its impact on the glucosinolate content of the garden candytuft were studied. Different copper sources (adsorbents or solution) were used. Generally, the seedlings copper uptake from the adsorbents was in the amount needed for its growth and development with the beneficial or no impact on the glucosinolate content. The lowest copper concentration was detected in the total seedlings biomass which grew in the humus with the addition of Cu-exchanged zeolite NaX (27.88 μg g−1 DW) having glucosinolate content of 9757.81 µg g−1 DW (23.86 µmol g−1 DW). The highest copper concentration among all the garden candytuft samples was detected in the seedlings watered with CuSO4∙5H2O solution (514.63 μg g−1 DW) with a sharp decrease of the glucosinolate content 3103.33 µg g−1 DW (7.59 µmol g−1 DW). Based on the results obtained, the garden candytuft can be considered as a copper accumulator plant.