Decrease in the genotoxicity of metal-contaminated soils with biochar amendments

Abstract

Biochar amendments, i.e., the solid product of biomass pyrolysis, reduce soil metal availability, which may lower the toxicity of metal-contaminated soils. A direct link between the decrease in soil metal availability and improved plant development is however often difficult to establish, as biochar may induce undesirable side effects on plant growth, e.g., a modification to plant nutrition. In order to investigate toxicity processes at a cellular level, roots of Vicia faba were exposed for 7 days to three metal-contaminated substrates and one control soil, amended with a 0 or 5% (w/w) addition of a wood-derived biochar. Exposure to pure biochar was also tested. Root tip cells were then observed to count the number of micronuclei as an estimation of DNA damage and the number of cells at mitosis stage. Results showed that biochar amendments led to a significant decrease in soil metal availability (Cd, Cu, Ni, Pb, and Zn) and to enhance root development on acidic substrates. The micronucleus frequency in root tip cells was positively correlated and the number of mitotic cells negatively, to the extractability of Zn in soils and to the concentration of Zn in secondary roots. Exposure to pure biochar caused a lower production of roots than most soil substrates, but led to the lowest number of observed micronuclei. In conclusion, biochar amendments can reduce the genotoxicity associated with the presence of metallic contaminants in soils, thereby potentially improving plant growth.

Combining biochar and grass-legume mixture to improve the phytoremediation of soils contaminated with potentially toxic elements (PTEs)

“…This can be ascribed to the neutralization of pH, increased nutrient availability, as well as the immobilization of PTEs in the C + B-soil [ 42 , 43 ]. Our results agree with those of Helaoui et al [ 44 ], who showed that biochar improved the adaptability of vetch to Cd-contaminated soils, and Rees et al [ 45 ], which demonstrated that biochar was able to reduce the genotoxicity associated with the presence of Cd, Pb and Zn, thus promoting the growth of vetch in contaminated soils. The general improvement of soil quality favored by biochar appeared to be less effective on the growth of ryegrass alone ( Fig.…”

“…Presumably, biochar addition, by increasing the C/N ratio of the soil, enhanced the biological N fixation of vetch [ 49 ], which in turn may have promoted increased N uptake and growth of ryegrass [ 50 ]. Similar results were reported by Rees et al [ 45 , 51 ], who observed, in two separate experiments, improved growth of Lolium perenne and Vicia faba when grown alone in PTEs-contaminated soils treated with biochar. Beneficial effects of biochar on the yield of vetch and ryegrass grown in mixed cropping, but in uncontaminated soils, were also reported by different authors [e.g.…”

Biochars as culture medium additives influence organogenic potential of plant explants through changes in endogenous phytohormone and carbohydrate contents in Daphne species

“…Effects of biochar application to the soil on plant growth performance and physiology were evaluated in numerous greenhouse and field studies (Rees et al 2016(Rees et al , 2017Hafez et al 2020;Martos et al 2020;Jaiswal et al 2020). In turn, its impact on in vitro cultured plants was rarely investigated.…”

Degraded Land Analyses of Brantas River Basin to Support Land Rehabilitation

“…Biochar dapat digunakan untuk memodifikasi sifat-sifat tanah terutama di daerah tropis yang terdegradasi (Du et al, 2017). Biochar mampu memperbaiki sifat fisik tanah seperti agregat tanah, aerasi tanah, dan kemampuan tanah dalam menyimpan air (Mukherjee & Lal, 2013), selain itu biochar juga dapat menurunkan kandungan logam berat tanah yang tercemar (Rees et al, 2017). Biochar juga dapat meningkatkan pertumbuhan tanaman seperti pada kelapa sawit (tinggi, diameter, dan jumlah daun) dan meningkatkan serapan unsur hara N (Santi, 2017).…”