Arbuscular Mycorrhizal Fungi and Rhizobacteria Promote Growth of Russian Knapweed (Acroptilon repens L.) in a Cd-Contaminated Soil
Improving soil microbial activity and using microbial synergistic relations, such as arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR), are of major importance for plant growth in contaminated soils with heavy metals. In this study, growth of Russian knapweed (Acroptilon repens L.) inoculated with either AMF or PGPR was studied in a soil spiked with 0, 10, 30, 100 mg kg− 1 cadmium (Cd). AMF colonization rate in roots significantly declined by an average of 63.6% as soil Cd level increased. Similarly, shoot dry weight significantly declined as soil Cd level increased, but inoculation with either AMF or PGPR showed a promoting effect on shoot biomass compared with the non-inoculated plants. Cd concentrations in the shoots were higher in the PGPR-treated plants compared with control plants, whereas Cd concentrations in the roots were higher in the AMF-treated plants. The highest amount of Cd extraction was observed for PGPR-inoculated plants, followed by AMF-inoculated plants, and control plants. Elevated Cd level in the soil decreased the photosynthetic pigments chlorophyll a, chlorophyll b, and carotenoids, but AMF- and PGPR-treated plants alleviated this effect compared with control plants. Similarly, relative water content (RWC) of Russian knapweed plants decreased with elevated Cd level in the soil, but RWC was higher in the inoculated plants in all Cd levels in the soil. Inoculation of Russian knapweed plants with AMF and PGPR may effectively contribute to restoration of Cd-contaminated soils and can promote phytoremediation processes. Further research could focus on the effectiveness of Russian knapweed plant inoculation with AMF and PGPR in alleviating heavy metal toxicity in different soil types.
KeywordsCadmium Inoculation Mycorrhiza Phytoremediation Rhizobacteria
The authors gratefully thank the Research Vice Chancellor of Urmia University for the financial support provided to the project. They also acknowledge the help provided by the Soil and Water Research Institute (SWRI) in preparing the microbial isolates.
Compliance with Ethical Standards
Conflict of interest
The authors declare no conflict of interest.
- Chao CC, Wang YP (1991) Effects of heavy metals on vesicular–arbuscular mycorrhizae and nitrogen fixation of soybean in major soil groups of Taiwan. J Chin Chem Soc 29:290–300Google Scholar
- Chibuike GU, Obiora SC (2014) Heavy metal polluted soils: effect on plants and bioremediation methods. App Environ Soil Sci 2014:752708Google Scholar
- Gaballah MS, Gomaa AM (2005) Interactive effect of Rhizobium inoculation, sodium benzoate and salinity on performance and oxidative stress in two faba bean varieties. Int J Agric Biol 7:495–498Google Scholar
- Gee GW, Or D (2002) Particle-size analysis. In: Dane JH, Topp GC (eds) Methods of soil analysis, Part 4. Physical methods. Soil Science Society of America, Madison, pp 255–293Google Scholar
- Gupta PK (2000) Soil, plant, water, and fertilizer analysis. Agrobios, New DelhiGoogle Scholar
- Huang Y, Tao S, Chen YJ (2005) The role of arbuscular mycorrhiza on change of heavy metal speciation in rhizosphere of maize in wastewater irrigated agriculture soil. J Environ Sci 17:276–280Google Scholar
- Miller JJ, Curtin D (2006) Electrical conductivity and soluble ions. In: Carter MR, Gregorich EG (eds) Soil sampling and methods of analysis, 2nd edn. CRC Press, Boca Raton, pp 161–171Google Scholar
- Pérez-Montaño F, Alías-Villegas C, Bellogín RA, del Cerro P, Espuny MR, Jiménez-Guerrero I, López-Baena FJ, Ollero FJ, Cubo T (2014) Plant growth promotion in cereal and leguminous agricultural important plants: from microorganism capacities to crop production. Microbiol Res 169:325–336CrossRefPubMedGoogle Scholar
- Rayment GE, Higginson FR (1992) Laboratory handbook of soil and water chemical methods. Inkata Press, MelbourneGoogle Scholar
- Rengasamy P, Churchman GJ (1999) Cation exchange capacity, exchangeable cations and sodicity. In: Peverill KI, Sparrow LA, Reuter DJ (eds) Soli analysis: an interpretation manual. CSIRO Publishing, MelbourneGoogle Scholar
- Rezapour S, Kouhinezhad P, Samadi A (2017) The potential ecological risk of soil trace metals following over five decades of agronomical practices in a semi-arid environment. Chem Ecol 34:1–16Google Scholar
- Shah K, Mankad AU, Reddy MN (2017) Cadmium accumulation and its effects on growth and biochemical parameters in Tagetes erecta L. J Pharmacogn Phytochem 6:111–115Google Scholar
- Soil Survey Staff (2010) Soil taxonomy: a basic system of soil classification for making and interpreting soil surveys, 2nd edn. USDA-NRCS. Agriculture Handbook No. 436, US Government Printing Office, p 870Google Scholar
- Soon YR, Abboud S (1993) Cadmium, chromium, and nickel. In: Carter MR (ed) Soil sampling and methods of soil analysis. Lewis Publishers, Boca Raton, pp 101–108Google Scholar
- Takács T, Biró B, Voros I (2002) Arbuscular mycorrhizal effect on heavy metal uptake of ryegrass (Lolium perenne L.) in pot culture with polluted soils. In: Horst WWJ, Scheck MK, Bürkert A, Claassen N, Flessa H, Frommer WB, Goldback HW, Olfs HW, Römheld V, Sattelmacher B, Schmidhalter U, Schubert S, von Wirén N, Wittenmayer L (eds) Plant nutrition: food security and sustainability of agro-ecosystems through basic and applied research (developments in plant and soil sciences). Kluwer Academic Publishers, The Netherlands, pp 480–481Google Scholar