Seed germination, root elongation, root-tip mitosis, and micronucleus induction of five crop plants exposed to chromium in fluvo-aquic soil

Abstract

The present study aimed to determine the toxic effects of chromium (Cr) on cabbage (Brassica oleracea), cucumber (Cucumis sativus), lettuce (Lactuca sativa), wheat (Triticum aestivum), and corn (Zea mays), and identify the sensitive plant species and appropriate bioassays for potential use in phytotoxicity assessment of Cr in soil. Results showed that seed germination might not be a sensitive assay for assessing Cr toxicity because at most of the Cr levels there were no toxic effects. Root elongation was more sensitive to Cr than seed germination. The lowest concentration of adverse effect (LOAEC) of lettuce was 20 mg Cr/kg(-1) soil, and that of the other 4 species was 50 mg Cr/kg(-1) soil. The mitotic index fluctuated with increasing Cr concentration, thus it was insufficient to assess toxicity of Cr in soil. However, micronucleus assay showed that 5 mg Cr/kg(-1) soil caused a significant increase in micronucleus frequency in cabbage, cucumber, and lettuce. For wheat and corn, however, the LOAEC was 20 and 50 mg/Cr/kg(-1) soil, respectively. Furthermore, the analysis of Cr accumulation showed that lettuce significantly accumulated Cr for all the tested concentrations. However, corn and wheat significantly accumulated Cr only with the highest tested dose. This may explain the higher inhibitory effects of Cr on root growth. It can be concluded that root elongation and micronucleus assay are good indicators to assess the phytotoxicity of Cr in soil. Lettuce is the most sensitive species for indicating the toxicity of Cr in soil.

An investigation into the use of Australian native plants and designer metal-binding particles for remediation of metal-contaminated landscapes

“…The finding in this study is in agreement with previous studies demonstrating high sensitivity of root length in response to toxicity of various metals (As, Cd, Cr, Pb) compared to other germination indicators such as germination rate, shoot length, maximum germination percentage and shoot biomass in both crop plants (Xiong, 1998, Jamali et al, 2006, Almas et al, 2012 and recognized metal-tolerant species (Rossato et al, 2011. In addition, Hou et al (2014) studied toxicity effects of chromium (Cr) on various plant species including Brassica oleracea, Cucumis sativus, Lactuca sativa, Triticum aestivum and Zea mays and found that root elongation was one of the most sensitive indicators for phytotoxicity of Cr in soil. Mishra and Choudhuri (1998) reported that shoot and root tolerance indexes were the most sensitive indicators for biomonitoring of phytotoxic effects of Pb and mercury (Hg) on rice cultivars.…”

“…Roots are often used to measure heavy metal tolerance of plants because they are more responsive to metal toxicity in the environment (Xiong, 1998). This might be because roots function as the initial absorptive organs and are more directly exposed to metals compared to other plant tissues (Xiong, 1998, Hou et al, 2014. Therefore, the presence of metals may reduce the ability of roots to absorb water and nutrients from soils and may inhibit cell division in roots (Lefèvre et al, 2009, Hou et al, 2014; consequently, germinating seeds are not able to develop and grow.…”

Efficiency of co-composting process to remove genotoxicity from sewage sludge contaminated with hexavalent chromium

“…As already shown, sewage sludge is known to contain genotoxic compounds such as PHAs, PCB and heavy metals (Amir et al, 2005;Amir et al, 2005Amir et al, 2005Kapanen et al, 2013., El Fels et al, 2014a. The Cr(VI) is reported to inhibit not only cell multiplication but also the cell elongation by inducing chromosal aberrations (Scoccianti et al, 2006;Hou et al, 2014). The ability of Cr(VI) to pass through the cell membrane and potentially result in sitespecific that could enhance their toxicity.…”

“…Corradi et al (1993) showed that Cr(VI) effects is an impaired function of the plasma membrane leading to plasmolysis, and inhibition biosynthesis pigment occurred at 48 h of exposure. A depressive effect of Cr on the activity of amylases and subsequent transport of sugars to the embryo axes was demonstrated (Hou et al, 2014). Furthermore, protease activity increases with the Cr treatments (López-Luna et al, 2009).…”

DNA Damage in Vicia faba by Exposure to Agricultural Soils from Tlaxcala, Mexico

“…These pollutants have been linked to genotoxic, neurological, immunological, and reproductive effects (Buccini 2003). Some plants are used as environmental biomonitors for detecting pollutants with genotoxic capacity and may be an alternative system in the first stages of studies to detect possible genetic damage (Ventura et al 2013;Hou et al 2014). Mitotic cells from V. faba roots have been used to assess some DNA damage markers, such as chromosome aberrations and MNF (Dong and Zhang 2010;Juárez-Santacruz et al 2013).…”