Publications by authors named "Nigel Swarts"

Background And Aims: Plant-fungus symbioses may experience temporal turnover during the ontogenetic or phenological development of the host, which can influence the ecological requirements of the host plant. In this study, we investigate temporal turnover of Ceratobasidiaceae orchid mycorrhizal fungal (OMF) communities in Prasophyllum (Orchidaceae), asking whether OMF communities are subject to temporal change attributable to orchid phenology or ontogeny.

Methods: Roots of adult Prasophyllum frenchii, Prasophyllum lindleyanum and Prasophyllum sp.

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Optimizing the utilization of applied nitrogen (N) in fruit trees requires N supply that is temporally matched to tree demand. We investigated how the timing of N application affected uptake, allocation, and remobilization within 14-year-old "Gala"/M26 apple trees ( Borkh) over two seasons. In the 2017-2018 season, 30 g N tree of 5.

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Background And Aims: Mycorrhizal fungi are a critical component of the ecological niche of most plants and can potentially constrain their geographical range. Unlike other types of mycorrhizal fungi, the distributions of orchid mycorrhizal fungi (OMF) at large spatial scales are not well understood. Here, we investigate the distribution and diversity of Ceratobasidium OMF in orchids and soils across the Australian continent.

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Background: The determination of fresh whole raspberry quality is a laborious and expensive process for commercial producers and researchers. Quantitative results for raspberry quality parameters are currently determined using a range of chemical tests within a commercial laboratory. The present work is the first calibration and validation of near infra-red spectroscopy (NIRS) for instantaneous and simultaneous of prediction of raspberry quality parameters.

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Background And Aims: In orchid conservation, quantifying the specificity of mycorrhizal associations, and establishing which orchid species use the same fungal taxa, is important for sourcing suitable fungi for symbiotic propagation and selecting sites for conservation translocation. For Caladenia subgenus Calonema (Orchidaceae), which contains 58 threatened species, we ask the following questions. (1) How many taxa of Serendipita mycorrhizal fungi do threatened species of Caladenia associate with? (2) Do threatened Caladenia share orchid mycorrhizal fungi with common Caladenia? (3) How geographically widespread are mycorrhizal fungi associated with Caladenia?

Methods: Fungi were isolated from 127 Caladenia species followed by DNA sequencing of the internal transcibed spacer (ITS) sequence locus.

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Varietal base ciders were produced from three varieties of dessert apples ('Pink Lady®', 'Royal Gala' and 'Red Delicious') at pre-commercial, commercial and post-commercial harvest timings. Rapid analytical methods were used to categorise the base ciders, and data analysed using principal component analysis (PCA). The titratable acidity of apple must was significantly higher for the pre-commercial harvest fruit for both the 'Royal Gala' and 'Red Delicious' varieties.

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Background And Aims: Many terrestrial orchids have an obligate requirement for mycorrhizal associations to provide nutritional support from germination to establishment. This study will investigate the ability of orchid mycorrhizal fungi (OMF) to utilize a variety of nutrient sources in the nutrient-impoverished (low organic) soils of the Southwest Australian Floristic Region (SWAFR) in order to effectively compete, survive and sustain the orchid host.

Methods: Mycorrhizal fungi representing key OMF genera were isolated from three common and widespread species: Pterostylis recurva, Caladenia flava and Diuris corymbosa, and one rare and restricted species: Drakaea elastica.

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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.

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Terrestrial orchid germination, growth and development are closely linked to the establishment and maintenance of a relationship with a mycorrhizal fungus. Mycorrhizal dependency and specificity varies considerably between orchid taxa but the degree to which this underpins rarity in orchids is unknown. In the context of examining orchid rarity, large scale in vitro and in situ germination trials complemented by DNA sequencing were used to investigate ecological specialization in the mycorrhizal interaction of the rare terrestrial orchid Caladenia huegelii.

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Orchids, one of the largest families of flowering plants, face an uncertain future through overexploitation, habitat loss and impacts of climate change. With their intricate abiotic and biotic dependencies, orchids typify the plight of global plant resources and, thus, provide ideal model species for ecological tracking and focussing conservation programs. Botanic gardens worldwide have traditionally been major centres of excellence in orchid horticulture, research and conservation as orchids generate wide public and educational appeal.

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Background: Conservation through reserves alone is now considered unlikely to achieve protection of plant species necessary to mitigate direct losses of habitat and the pervasive impact of global climate change. Assisted translocation/migration represent new challenges in the face of climate change; species, particularly orchids, will need artificial assistance to migrate from hostile environments, across ecological barriers (alienated lands such as farmlands and built infrastructure) to new climatically buffered sites. The technology and science to underpin assisted migration concepts are in their infancy for plants in general, and orchids, with their high degree of rarity, represent a particularly challenging group for which these principles need to be developed.

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