THE IMPACT OF HEAVY METALS ON BENEFICIAL MICROBES' PLANT GROWTH PROMOTION AND THEIR EFFECT ON VIGNA RADIATA

Abstract

This study investigates the differential influence of heavy metals on plant growth-promoting (PGP) attributes of beneficial microbes and their ability to promote the growth of Vigna radiata (mung bean). Soil samples were collected and used to isolate PGP microbes, which were identified using morphological, biochemical, and molecular techniques. Heavy metals, including lead, cadmium, arsenic, and mercury, were applied at various concentrations to evaluate their impact on microbial growth and PGP activities such as phosphate solubilization, siderophore production, indole acetic acid (IAA) production, and ACC deaminase activity. Greenhouse experiments assessed the growth parameters of Vigna radiata, including germination rate, plant height, root length, and biomass, in soils treated with heavy metals, both with and without microbial inoculation. The results indicated that higher concentrations of heavy metals significantly reduced PGP activities and plant growth parameters. However, inoculation with heavy metal-resistant PGP microbes improved these parameters under heavy metal stress, demonstrating the potential of these microbes to mitigate heavy metal toxicity and enhance plant growth. This research highlights the importance of utilizing PGP microbes for sustainable agricultural practices in heavy metal-contaminated soils.