De Long, JR and Swarts, ND and Dixon, KW and Egerton-Warburton, LM, Mycorrhizal preference promotes habitat invasion by a native Australian orchid: Microtis media, Annals of Botany, 111, (3) pp. 409-418. ISSN 0305-7364 (2013) [Refereed Article]
Copyright 2012 The Authors.
Background and Aims: Mycorrhizal specialization has been shown to limit recruitment capacity in orchids, but an increasing number of orchids are being documented as invasive or weed-like. The reasons for this proliferation were examined by investigating mycorrhizal fungi and edaphic correlates of Microtis media, an Australian terrestrial orchid that is an aggressive ecosystem and horticultural weed.
Methods: Molecular identification of fungi cultivated from M. media pelotons, symbiotic in vitro M. media seed germination assays, ex situ fungal baiting of M. media and co-occurring orchid taxa (Caladenia arenicola, Pterostylis sanguinea and Diuris magnifica) and soil physical and chemical analyses were undertaken.
Key Results: It was found that: (1) M. media associates with a broad taxonomic spectrum of mycobionts including Piriformospora indica, Sebacina vermifera, Tulasnella calospora and Ceratobasidium sp.; (2) germination efficacy of mycorrhizal isolates was greater for fungi isolated from plants in disturbed than in natural habitats; (3) a higher percentage of M. media seeds germinate than D. magnifica, P. sanguinea or C. arenicola seeds when incubated with soil from M. media roots; and (4) M. media-mycorrhizal fungal associations show an unusual breadth of habitat tolerance, especially for soil phosphorus (P) fertility.
Conclusions: The findings in M. media support the idea that invasive terrestrial orchids may associate with a diversity of fungi that are widespread and common, enhance seed germination in the host plant but not co-occurring orchid species and tolerate a range of habitats. These traits may provide the weedy orchid with a competitive advantage over co-occurring orchid species. If so, invasive orchids are likely to become more broadly distributed and increasingly colonize novel habitats.>
|Item Type:||Refereed Article|
|Keywords:||terrestrial orchid, mycorrhizal fungi, disturbed habitats, south-western Australia, invasive species, Microtis media|
|Research Division:||Biological Sciences|
|Objective Division:||Plant Production and Plant Primary Products|
|Objective Group:||Horticultural crops|
|Objective Field:||Ornamentals, natives, flowers and nursery plants|
|UTAS Author:||Swarts, ND (Dr Nigel Swarts)|
|Web of Science® Times Cited:||33|
|Deposited By:||Tasmanian Institute of Agriculture|
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