Elsevier

Pedosphere

Volume 24, Issue 4, August 2014, Pages 553-562
Pedosphere

PEDOSPHERE
Microbial Biomass and PLFA Profile Changes in Rhizosphere of Pakchoi (Brassica chinensis L.) as Affected by External Cadmium Loading

https://doi.org/10.1016/S1002-0160(14)60041-2Get rights and content

Abstract

The effects of root activity on microbial response to cadmium (Cd) loading in the rhizosphere are not well understood. A pot experiment in greenhouse was conducted to investigate the effects of low Cd loading and root activity on microbial biomass and community structure in the rhizosphere of pakchoi (Brassica chinensis L.) on silty clay loam and silt loamy soil. Cd was added into soil as Cd(NO3)2 to reach concentrations ranging from 0.00 to 7.00 mg kg−1. The microbial biomass carbon (MBC) and community structure were affected by Cd concentration, root activity, and soil type. Lower Cd loading rates (< 1.00 mg kg−1) stimulated the growth of pakchoi and microorganisms, but higher Cd concentrations inhibited the growth of microorganisms. The content of phospholipid fatty acids (PLFAs) was sensitive to increased Cd levels. MBC was linearly correlated with the total PLFAs. The content of general PLFAs in the fungi was positively correlated with the available Cd in the soil, whereas those in the bacteria and actinomycetes were negatively correlated with the available Cd in the soil. These results indicated that fungi were more resistant to Cd stress than bacteria or actinomycetes, and the latter was the most sensitive to Cd stress. Microbial biomass was more abundant in the rhizosphere than in the bulk soil. Root activity enhanced the growth of microorganisms and stabilized the microbial community structure in the rhizosphere. PLFA analysis was proven to be sensitive in detecting changes in the soil microbial community in response to Cd stress and root activity.

References (45)

  • M. Liao et al.

    Influence of lead acetate on soil microbial biomass and community structure in two different soils with the growth of Chinese cabbage (Brassica chinensis)

    Chemosphere.

    (2007)
  • N. Lorenz et al.

    Response of microbial activity and microbial community composition in soils to long-term arsenic and cadmium exposure

    Soil Biol. Biochem.

    (2006)
  • P. Nielsen et al.

    Ester-linked polar lipid fatty acid profiles of soil microbial communities: a comparison of extraction methods and evaluation of interference from humic acids

    Soil Biol. Biochem.

    (2000)
  • P. Nyitrai et al.

    Characterization of the stimulating effect of low-dose stressors in maize and bean seedlings

    J. Plant Physiol.

    (2003)
  • M.N.V. Prasad et al.

    Physiological responses of Lemna trisulca L. (duckweed) to cadmium and copper bioaccumulation

    Plant Sci.

    (2001)
  • G. Renella et al.

    Microbial activity and hydrolase activities during decomposition of root exudates released by an artificial root surface in Cd-contaminated soils

    Soil Biol. Biochem.

    (2006)
  • G. Renella et al.

    Degradation of low molecular weight organic acids complexed with heavy metals in soil

    Geoderma.

    (2004)
  • G. Renella et al.

    Microbial activity and hydrolase synthesis in long-term Cd-contaminated soils

    Soil Biol. Biochem.

    (2005)
  • G. Renella et al.

    Hydrolase activity, microbial biomass and community structure in long-term Cd-contaminated soils

    Soil Biol. Biochem.

    (2004)
  • R. Turpeinen et al.

    Microbial community structure and activity in arsenic-, chromium- and copper-contaminated soils

    FEMS Microbiol. Ecol.

    (2004)
  • K. Vig et al.

    Bioavailability and toxicity of cadmium to microorganisms and their activities in soil: a review

    Adv. Environ. Res.

    (2003)
  • Y.P. Wang et al.

    Heavy metal availability and impact on activity of soil microorganisms along a Cu/Zn contamination gradient

    J. Environ. Sci.

    (2007)
  • Cited by (21)

    • A field study reveals links between hyperaccumulating Sedum plants-associated bacterial communities and Cd/Zn uptake and translocation

      2022, Science of the Total Environment
      Citation Excerpt :

      This is why mine pollution has greater influence on Phragmites communis plants than other factors. The high rhizosphere alpha diversity observed in our data has also been reported elsewhere for plants grown in Cd and Zn polluted soil (Shentu et al., 2014; He et al., 2017), and is thought to be linked to root activities (e.g., high levels of organic exudates), which provide suitable ecological niches for bacterial growth (He et al., 2017). Sedum plants revealed the presence of three main bacterial phyla, Proteobacteria, Actinobacteria and Acidobacteria (Fig. S5), as previously reported for Arabidopsis and rice microbiomes and other plants in contaminated soils, including other Sedum ecotypes (Edwards et al., 2015; Visioli et al., 2015a; He et al., 2017; Hou et al., 2018; Guo et al., 2019).

    • Soil microbial community and abiotic soil properties influence Zn and Cd hyperaccumulation differently in Arabidopsis halleri

      2022, Science of the Total Environment
      Citation Excerpt :

      A similar pattern was previously reported by Khan et al. (2010) and may be associated with differences in bacterial and fungal activities in M soils (Rajapaksha et al., 2004). Further, phospholipid fatty acid analysis – commonly used to quantify soil microbial responses to environmental stress – has shown positive correlation between soil available Cd and fungal indicators but for bacterial indicators the correlation is a negative one (Shentu et al., 2014). Of particular interest were the observed differences between A. halleri rhizosphere and background soil microbial communities from M and NM sites.

    • Effect of cadmium contamination on the rhizosphere bacterial diversity of Echinocactus platyacanthus

      2020, Rhizosphere
      Citation Excerpt :

      Thus, above 30 mg kg−1 cellular mechanisms would increase the maintenance energy and reduce the conversion of substrate into new microbial biomass. We found that microbial C decreased to concentrations higher than 40 mg kg−1, subsequent to the reduction of carbon mineralization and nitrogen fixation in soils (Shentu et al., 2014; Zhang et al., 2018) given by the negative correlation found between microbial C, organic carbon (CO) and NH4+. Similarly, CdW caused an increase in the abundance of diazotrophs at concentrations lower than 30 mg kg−1 (Fig. 2c).

    View all citing articles on Scopus

    Supported by the Department of Education of Zhejiang Province, China (No. Y200804542), the Innovative Research Team in Higher Educational Institutions of Zhejiang Province, China (No. T200912), the Environmental Protection Research Plan of Hangzhou, China (No. 2011008), and the Zhejiang Gongshang University, China (No. X13-01).

    View full text