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Research article2024Peer reviewedOpen access

Limited efficacy of a commercial microbial inoculant for improving growth and physiological performance of native plant species

Wong, Wei San; Ruscalleda-Alvarez, Jaume; Yong, Jean W. H.; Stevens, Jason C.; Valliere, Justin M.; Veneklaas, Erik J.

Abstract

The efficacy of a commercial microbial inoculant for improving the performance of 10 Western Australian woodland plant species was evaluated. Across all investigated species, inoculation had small effects on plant growth. Within each species, inoculation did not result in significant biomass gain, and effects on nitrogen nutrition and photosynthesis were variable and minimal.Soil microbial inoculants are increasingly being explored as means to improve soil conditions to facilitate ecological restoration. In southwestern Western Australia, highly biodiverse Banksia woodland plant communities are increasingly threatened by various factors including climate change, land development and mining. Banksia woodland restoration is necessary to conserve this plant community. The use of microbial inoculation in Banksia woodland restoration has not yet been investigated. Here, we evaluated the efficacy of a commercial microbial inoculant (GOGO Juice, Neutrog Australia Pty Ltd) for improving the performance of 10 ecologically diverse Banksia woodland plant species in a pot experiment. Plants were subjected to one of two watering regimes (well-watered and drought) in combination with microbial inoculation treatments (non-inoculated and inoculated). Plants were maintained under these two watering treatments for 10 weeks, at which point plants in all treatments were subjected to a final drought period lasting 8 weeks. Plant performance was evaluated by plant biomass and allocation, gas exchange parameters, foliar carbon and nitrogen and stable isotope (delta 15N and delta 13C) compositions. Plant xylem sap phytohormones were analysed to investigate the effect of microbial inoculation on plant phytohormone profiles and potential relationships with other observed physiological parameters. Across all investigated plant species, inoculation treatments had small effects on plant growth. Further analysis within each species revealed that inoculation treatments did not result in significant biomass gain under well-watered or drought-stressed conditions, and effects on nitrogen nutrition and photosynthesis were variable and minimal. This suggests that the selected commercial microbial inoculant had limited benefits for the tested plant species. Further investigations on the compatibility between the microorganisms (present in the inoculant) and plants, timing of inoculation, viability of the microorganisms and concentration(s) required to achieve effectiveness, under controlled conditions, and field trials are required to test the feasibility and efficacy in actual restoration environments.

Keywords

Banksia woodlands; microbial inoculation; mine site restoration; phytohormones; xylem sap

Published in

Conservation Physiology
2024, Volume: 12, number: 1, article number: coae037

    UKÄ Subject classification

    Horticulture
    Ecology
    Microbiology

    Publication identifier

    DOI: https://doi.org/10.1093/conphys/coae037

    Permanent link to this page (URI)

    https://res.slu.se/id/publ/123693