Native bacteria and cyanobacteria can influence seedling emergence and growth of native plants used in dryland restoration

10 páginas.- 2 figuras.- referencias

Seed-based ecosystem restoration has huge potential to restore degraded drylands. However, fewer than 10% of directly sown seeds transition to established seedlings. One of the potential factors restricting plant establishment in degraded soils is the low abundance and diversity of native soil micro-organisms. In this study, we investigated whether returning indigenous bacteria and cyanobacteria consortia to degraded dryland soils improved seedling emergence, survival and growth of native plants. We inoculated ‘culturable whole soil’ native heterotrophic bacteria and biocrust cyanobacteria individually and as a mixed inoculant into extruded pellets containing Acacia inaequilatera (Fabaceae) and Triodia epactia (Poaceae) seeds. The pellets were planted in an active minefield for 28 weeks and seedling emergence and total biomass of plants were determined. Cyanobacteria and bacteria inoculants increased the emergence of A. inaequilatera by 55% and 48%, respectively. Seedling emergence in T. epactia was increased by 20% by cyanobacteria but was not increased by bacteria. The only effect of inoculation on seedling survival or mass per surviving seedling in either species was an 11% reduction of the growth of T. epactia seedlings that were inoculated with cyanobacteria. Synthesis and applications: Our results suggest that the benefit of micro-organisms on plant establishment is both species specific and life stage specific, with particularly strong benefits in the early stages of recruitment. Our experiment was conducted under shade and with additional water, so a worthwhile future direction would be to quantify the effect of inoculation under unmodified field conditions. It would also be worthwhile monitoring the outcomes for longer than 28 weeks. Since seedling emergence is one of the critical challenges in dryland restoration, our study provides direct evidence in the use of native micro-organisms to potentially improve seedling emergence in seed-based dryland restoration.

This research was financed by the Australian Research Counci l Discovery Early Career Research Award DE180100570, the Hermon Slade Foundation (HSF 1808) and in collaboration withthe Department of Industry, Innovation and Science, Australian Government's Global Innovation Linkages Program (GIL 53873) project ‘Eco-engineering solutions to improve mine- site rehabilitationoutcomes’. MMR is supported by a Ramon y Cajal Fellowship from the Spanish Ministry of Science and Innovation (RYC2020- 029255-I).This project was also supported by the Holsworth Wildlife Research Endowment and The Ecological Society of Australia. We thank Nathalie Machado for her support in compiling OTU data and alsoassisting with pellet preparation, James Charlesworth for his sup -port in culturing the bacteria and Emma Stock for her support in thefield data collection. Open access publishing facilitated by Universityof New South Wales, as part of the Wiley - University of New South Wales agreement via the Council of Australian University Librarians

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