Phosphorus supply affects seedling growth of mycorrhizal but not cluster-root forming jarrah-forest species

Standish, R. J. ORCID: https://orcid.org/0000-0001-8118-1904, Daws, M. I. ORCID: https://orcid.org/0000-0002-9120-4724, Morald, T. K., Speijers, J., Koch, J. M., Hobbs, R. J. ORCID: https://orcid.org/0000-0003-4047-3147 and Tibbett, M. ORCID: https://orcid.org/0000-0003-0143-2190 (2022) Phosphorus supply affects seedling growth of mycorrhizal but not cluster-root forming jarrah-forest species. Plant and Soil, 472. pp. 577-594. ISSN 0032-079X doi: 10.1007/s11104-021-05268-2

Abstract/Summary

Aims Fertiliser is often used to kick-start ecological restoration despite growing evidence of the potentially negative impacts on plant diversity. Jarrah (Eucalyptus marginata) forest species growing on nutrient (especially phosphorus) impoverished soils in southwestern Australia have a suite of adaptations for phosphorus (P) acquisition, including the formation of cluster roots, and associations with mycorrhizal fungi. Here we investigated how escalating P supply, along with a stoichiometric adjustment of nitrogen (N) supply, impacted the growth and nutrition of a wide range of jarrah forest seedlings. Methods In a pot experiment, we measured seedling biomass and nutritional responses of 12 jarrah forest species to a gradient of P supply in relation to N supply, and for the mycorrhizal species, inoculation with arbuscular mycorrhizal fungi. Results Three cluster-root forming species did not respond to increasing P, probably because they were reliant on seed P. Generally, mycorrhizal species showed a positive biomass response to increasing P when N was available. Mycorrhizas benefited seedling growth at low P (9 mg P added per kg of jarrah forest soil) when N was also available, and were parasitic to seedling growth at high P (243 mg P/ kg soil) without additional N. Conclusions These results highlight importance of P and N supply in determining the nature of the symbiosis between plants and mycorrhizal fungi. Since P supply has the potential to reduce plant growth, for a range of species, our results suggest careful consideration of fertiliser amounts for ecological restoration of ecosystems adapted to nutrient poor soils.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/102683
Item Type	Article
Refereed	Yes
Divisions	Interdisciplinary centres and themes > Soil Research Centre Life Sciences > School of Agriculture, Policy and Development > Department of Sustainable Land Management > Centre for Agri-environmental Research (CAER)
Publisher	Springer
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