Role of plant growth promoting rhizobacteria in the alleviation of lead toxicity to Pisum sativum L.

Abstract

Plant-microbe interaction is a significant tool to tackle heavy metals problem in the soil. A pot trial was conducted to evaluate the efficiency of lead tolerant rhizobacteria in improving pea growth under Pb stress. Lead sulfate (PbSO₄) was used for spiking (250, 500, and 750 mg kg⁻¹). Results indicated that inoculation with Pb-tolerant PGPR strain not only alleviated the harmful impacts of Pb on plant growth but also immobilized it in the soil. PGPR in the presence of Pb at concentrations of 0, 250, 500 and 750 mg kg⁻¹, increased shoot and root lengths by 21, 15, 18% and 72, 80, 84%, respectively, than uninoculated control. Moreover, fresh biomass of shoots and roots were also increased by 51, 45, 35% and 57, 101, 139% respectively, at Pb concentrations of 250, 500 and 750 mg kg⁻¹. In addition, PGPR inoculation also reduced Pb concentration in the roots and shoots by 57, 55, 49% and 70, 56 and 58% respectively, than uninoculated control. So, PGPR proved to be an efficient option for reducing Pb mobility and can be effectively used for its phytostabilization.

Novelty statement

Lead (Pb) is highly noxious and second most toxic element in the nature having high persistence. It ranks 1^st in the priority list of hazardous substances and causes adverse effects after its entry into the living system. So, its remediation is inevitable. Plant growth promoting rhizobacteria (PGPR) possess the potential to not only survive under stressed environments, but also promote plant growth on account of their different plant growth promoting mechanisms.

Most researchers have worked on its bioaccumulation in plant body. This study however, used pea as a test crop and caused Pb phytostabilization and thereby, suppressed its entry in the above-ground plant parts.

Keywords:

• Plant growth promoting rhizobacteria (PGPR)
• Bioaugmentation
• Lead (Pb)
• Pisum sativum L.
• heavy metal

Acknowledgment

Author feels immense pleasure in expressing its gratitude to Soil Microbiology and Biochemistry Laboratory, Institute of Soil and Environmental Sciences, University of Agriculture Faisalabad, Pakistan for providing space for the smooth running of the experiment.

Additional information

Funding

Author acknowledges Higher Education Commission (HEC) of Pakistan for providing funds to the researcher under Indigenous Fellowship program, Phase II, Batch III.