Journal articles on the topic 'Diuris orchids'
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1
Grant, Carl D., and John Koch. "Orchid species succession in rehabilitated bauxite mines in Western Australia." Australian Journal of Botany 51, no. 4 (2003): 453. http://dx.doi.org/10.1071/bt02127.
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Twenty-three orchid species were recorded in Alcoa's permanent vegetation-monitoring plots in unmined and rehabilitated jarrah forest. Of these, 22 were identified in the unmined jarrah forest and 20 were recorded in rehabilitated areas of between 1 and 31 years old. Three species (Cyrtostylis ovata, Lyperanthus serratus and Prasophyllum elatum) were only recorded in the unmined forest and one species was only recorded in rehabilitated areas (Diuris carinata). The overall density of native orchids in the forest was 13 755 plants ha–1, 10 times greater than the density in rehabilitated areas (1381 plants ha–1). The most abundant species in the forest were Cyrtostylis robusta, Caladenia flava, Pterostylis nana and Thelymitra crinita, all with densities greater than 1000 plants ha–1. The most abundant species in the rehabilitated areas were Microtis media, Disa bracteata (an introduced species), Caladenia flava, Pterostylis nana, Diuris longifolia and Pterostylis vittata, all with densities greater than 60 plants ha–1. In rehabilitation older than 10 years, the density of orchids increased to 2685 plants ha–1. Burning in rehabilitated areas resulted in large increases in orchid densities. It is believed that orchid colonisation of rehabilitated bauxite mines is dependent on symbiotic mycorrhiza, which are in turn dependent on development of an organic litter component in the soil.
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Scaccabarozzi, Daniela, Andrea Galimberti, Kingsley W. Dixon, and Salvatore Cozzolino. "Rotating Arrays of Orchid Flowers: A Simple and Effective Method for Studying Pollination in Food Deceptive Plants." Diversity 12, no. 8 (July 22, 2020): 286. http://dx.doi.org/10.3390/d12080286.
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Floral deception has been observed in several genera in angiosperms, but is most common in the Orchidaceae. Pollination mechanisms in food deceptive plants are often difficult to assess, as visitation frequency by insects requires numerous hours of field observations to ascertain. Here, for the first time, we describe in detail and validate a simple and effective method that extends previous approaches to increase the effectiveness of pollination studies of food deceptive orchids. We used an orchid of southwest Australia, Diuris brumalis (Orchidaceae), that visually mimics model plants belonging to the genus Daviesia (Faboideae). Arrays of orchid flowers were placed and moved systematically in proximity to model plants, resulting in rapid attraction of the pollinators of D. brumalis. We compared pollinaria removal (as an indicator of pollination success) in naturally growing orchids with pollinaria removal in arrays of orchid flowers in the same sites. We showed that the proposed method greatly enhances pollinator attractiveness in food deceptive systems with very low pollination rates, and we compared its efficiency with other similar methods. The approach can be used for observing pollinator behavioural patterns and confirming effective pollinators for food deceptive species with low insect visitation rates.
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Batty, A. L., M. C. Brundrett, K. W. Dixon, and K. Sivasithamparam. "In situ symbiotic seed germination and propagation of terrestrial orchid seedlings for establishment at field sites." Australian Journal of Botany 54, no. 4 (2006): 375. http://dx.doi.org/10.1071/bt04024.
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The establishment of five species of temperate terrestrial orchids (Caladenia arenicola Hopper & A.P.Brown, Diuris magnifica D.L.Jones, D. micrantha D.L.Jones, Pterostylis sanginea D.LJones & M.A.Clem. and Thelymitra manginiorum ms) in natural habitat through in situ seed sowing, or by planting of seedlings and dormant tubers, was evaluated. Seed of the Western Australian temperate terrestrial taxa, Caladenia arenicola and Pterostylis sanguinea germinated best when sown into soil inoculated with mycorrhizal fungi at field sites but failed to develop the tubers necessary for surviving summer dormancy. However, seedling survival improved when actively growing symbiotic seedlings were transferred to natural habitat during the growing season. Caladenia arenicola and P. sanguinea seedlings survived the initial transfer to field sites but only P. sanguinea survived into the second growing season. Highest survival was obtained by translocating dormant tubers of C. arenicola and Diuris magnifica, with D. magnifica persisting at the site 5 years after translocation. However, outplanted C. arenicola survived for only 2 years. In another trial, where seedlings and dormant tubers of a rare orchid Thelymitra manginiorum were translocated into eucalypt woodland, 18% persisted after 5 years. The rare orchid D. micrantha exhibited the highest survival rates, with greater than 80% of tubers surviving 5 years after transfer of mature dormant tubers to field sites. This study highlights the benefit of using optimised methods for seedling production by symbiotic germination and nursery growth to produce advanced seedlings or dormant tubers to maximise the survival of translocated plants. It also demonstrates the need to consider different strategies when dealing with individual species.
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Sommerville, Karen D., John P. Siemon, Chris B. Wood, and Catherine A. Offord. "Simultaneous encapsulation of seed and mycorrhizal fungi for long-term storage and propagation of terrestrial orchids." Australian Journal of Botany 56, no. 7 (2008): 609. http://dx.doi.org/10.1071/bt08008.
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Ex situ conservation of threatened terrestrial orchids requires the simultaneous conservation of their mycorrhizal associations. A method for encapsulating both seed and fungi in alginate beads (known as encapsulation–dehydration) was applied to the storage and propagation of two endangered orchid species in NSW, Australia—Pterostylis saxicola D.L.Jones & M.A.Clem. and Diuris arenaria D.L.Jones. We tested the effect of storage duration and temperature on fungal recovery and germination potential in vitro, and recorded survival for seedlings subsequently transferred to potting mix. Storage at 23°C significantly reduced fungal recovery and germination for both species after only 3 months (P < 0.05), whereas storage at 4°C significantly reduced fungal recovery for P. saxicola after 6 months (P < 0.05). Storage for 6 months at −18 and −196°C had no significant effect on the fungal recovery and germination percentages of either species. All beads transferred directly from in vitro culture to potting mix resulted in the establishment of at least one seedling, and production of a healthy tuberoid, when transferred near the commencement of the natural growing season. The encapsulation–dehydration method may have a practical application for use in ex situ conservation of other terrestrial orchids, as well as their mycorrhizal fungi.
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Quay, Letitia, Jen A. McComb, and Kingsley W. Dixon. "Methods for ex Vitro Germination of Australian Terrestrial Orchids." HortScience 30, no. 7 (December 1995): 1445–46. http://dx.doi.org/10.21273/hortsci.30.7.1445.
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Seeds of two Australian terrestrial orchid species (Caladenia latifolia R.Br. and Diuris magnifica D. Jones) were germinated in a potting mix of Allocasuarina fraseriana (Miq.) L. Johnson leaf mulch and perlite (1:1). The potting mix was irradiated (7 Gy for 14 hours), steam pasteurized (70C for 30 minutes) or nontreated, and inoculated with the appropriate mycorrhizal fungus for each species, a sterile red fungus (SRF), or both. Protocorm formation and green shoots were evident at 8 and 10 weeks, respectively, after seed sowing. The highest mean number of seedlings was 84 for C. latifolia and 234 for D. magnifica per 270-ml container in pasteurized potting mix inoculated with mycorrhizal fungi and SRF. Shoots were longest after 20 weeks (28 mm for C. latifolia and 52 mm for D. magnifica, respectively) in pasteurized potting mix inoculated with mycorrhizal fungi only. Germination was absent in control treatments without mycorrhizal fungi; with SRF only; or in nonsterile potting mix with mycorrhizal fungi, SRF, or both.
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Dowling, Nicole, and Manfred Jusaitis. "Asymbiotic in vitro germination and seed quality assessment of Australian terrestrial orchids." Australian Journal of Botany 60, no. 7 (2012): 592. http://dx.doi.org/10.1071/bt12133.
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Determining the seed quality and germination requirements for threatened orchid species in storage is vital for future conservation efforts. Seeds of many Australian terrestrial orchid species are held in conservation collections around the country, but few have been germinated in vitro, fuelling concerns over their long-term viability. This study tested three methods of assessing orchid seed quality; asymbiotic germination was compared with vital staining using triphenyltetrazolium chloride or fluorescein diacetate. Six culture media were examined for efficacy in promoting asymbiotic seed germination of four Australian terrestrial orchid species (Pterostylis nutans, Microtis arenaria, Thelymitra pauciflora and Prasophyllum pruinosum). Germination occurred on all media but germination rates were consistently highest on BM1 and development was most advanced on BM1, P723 and Malmgren media. Subsequent trials tested the efficacy of BM1 for asymbiotic germination of additional genera (Caladenia, Calochilus and Diuris), several congeneric species, and two species collected from several different provenances within each of their ranges. The results indicate that asymbiotic germination on BM1 medium is an effective technique for testing the performance of Australian terrestrial orchid seeds. The efficacy of vital stains to determine seed viability, however, remains uncertain, as significant disagreement between degree of staining and germinability was observed for some species.
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Batty, A. L., K. W. Dixon, M. Brundrett, and K. Sivasithamparam. "Long-term storage of mycorrhizal fungi and seed as a tool for the conservation of endangered Western Australian terrestrial orchids." Australian Journal of Botany 49, no. 5 (2001): 619. http://dx.doi.org/10.1071/bt01029.
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The impact of seed drying, seed storage and development of testing procedures for seed viability assessment was undertaken for a selection of common taxa with congeners that are rare and endangered (Caladenia, Diuris, Pterostylisand Thelymitra). Freshly collected seed showed significantly lower levels of germination compared with seed that had been subjected to drying over silica gel for 24 h. Seed dried over silica gel for 24 h and plunged into liquid nitrogen exhibited a further increase in germination levels. Germination of seed stored at 4, 18 or 22˚C for 1 year was substantially higher than freshly collected seed (4 weeks after dehiscence), but germination was highest overall after storage of dried seed in liquid nitrogen (–196˚C). Mycorrhizal fungi that promote the germination and growth of plants were also successfully preserved in liquid nitrogen. The use of cryoprotectants on fungal isolates had no observable deleterious effects on fungal regeneration. Histochemical staining procedures (tetrazolium, fluorescein diacetate and Evans blue) substantially overestimated seed viability, relative to symbiotic seed germination, for most seed treatments indicating a need for re-evaluation of the effectiveness of staining procedures for testing viability. The implications of the long-term ex situ storage of orchid seed and fungal symbionts for the conservation of endangered orchids is discussed.
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Duncan, Michael, and Paul D. Moloney. "Comparing wild and reintroduced populations of the threatened orchid Diuris fragrantissima (Orchidaceae) in south-eastern Australia." Australian Journal of Botany 66, no. 7 (2018): 459. http://dx.doi.org/10.1071/bt18047.
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Orchids have high rates of speciation and extinction, and are over-represented on threatened species lists. Reintroductions are being used with increasing frequency as an important tool for threatened orchid recovery. The ultimate aim of these reintroductions is to create a self-sustaining population that will reduce the risk of extinction for the species. In this case study, we test the hypotheses that state transition, annual survival, and seed production rates in a reintroduced population were equivalent to those in the wild population. These hypotheses were tested using long-term demographic monitoring datasets from a wild and a reintroduced population of Diuris fragrantissima, and analysed using Bayesian multistate capture–recapture and multinomial models. The results showed that emergent plants at the reintroduction site were more likely to transition to vegetative or unobserved states, and less likely to flower in the following year, than those at the wild site. This resulted in a strong trend through time away from emergent life states at the reintroduction site. The estimated annual survival rate was >90% at the wild site, and <80% in five of the seven years at the reintroduction site. Flowering was the most frequently recorded life state at the wild site. The fate of an individual flower was not affected by site (wild or reintroduction), but an increase in rainfall increased the probability that a flower would set seed and decreased the probability that it would be browsed. The reintroduction has failed to produce a stable, sustainable, long-term population, but it has been valuable in providing information that will inform the development and improvement of future D. fragrantissima reintroductions. Improving our knowledge in these areas should increase the chances of future D. fragrantissima reintroductions being assessed as a success.
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Batty, A. L., M. C. Brundrett, K. W. Dixon, and K. Sivasithamparam. "New methods to improve symbiotic propagation of temperate terrestrial orchid seedlings from axenic culture to soil." Australian Journal of Botany 54, no. 4 (2006): 367. http://dx.doi.org/10.1071/bt04023.
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This research aimed to improve the success of soil transfer of terrestrial orchid seedlings after symbiotic germination in the laboratory. Three native Western Australian terrestrial orchids (Caladenia arenicola Hopper & A.P.Brown, Diuris magnifica D.L.Jones and Thelymitra crinita Lindley) were used in this study. The key to improved seedling survival on transfer to soil was found to be the use of an intermediate stage between the Petri dish and soil where larger seedlings were grown in an axenic environment with controlled humidity. There was no apparent benefit of pre-inoculating potting medium with appropriate strains of mycorrhizal fungi for subsequent growth of symbiotic seedlings under glasshouse conditions. Initial survival of seedlings in the glasshouse was high. However, some seedlings failed to produce tubers (from modified roots or droppers) necessary for plant survival through the summer dormancy period, and this caused survival to decrease to 40–60% of the glasshouse-grown seedlings in the first year. The initiation of tubers on droppers by C. arenicola was inversely correlated with leaf size, with smaller plants more likely to form tubers. This suggests that leaves and tubers were competing for resources. However, larger seedlings that did tuberise had larger tubers that were more likely to survive summer dormancy. There was no correlation between leaf size and root tuber size in D. magnifica, but the number of tubers produced was greatest in larger plants. As with C. arenicola, plants of D. magnifica and T. crinita with larger tubers were more likely to survive summer dormancy. Methods developed in this study enable the production of both actively growing symbiotic seedlings and dormant tubers which improve the success of translocation of laboratory-grown terrestrial orchids to field sites.
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Wylie, Stephen J., Hua Li, Kingsley W. Dixon, Helen Richards, and Michael G. K. Jones. "Exotic and indigenous viruses infect wild populations and captive collections of temperate terrestrial orchids (Diuris species) in Australia." Virus Research 171, no. 1 (January 2013): 22–32. http://dx.doi.org/10.1016/j.virusres.2012.10.003.
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Beardsell, DV, MA Clements, JF Hutchinson, and EG Williams. "Pollination of Diuris maculata R Br (Orchidaceae) by Floral Mimicry of the Native Legumes Daviesia spp and Pultenaea scabra R Br." Australian Journal of Botany 34, no. 2 (1986): 165. http://dx.doi.org/10.1071/bt9860165.
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Several species of insects captured while feeding on flowers of the legumes Daviesia virgata and D. mimosoides carried pollinia of the orchid Diuris maculata on their heads. In contrast, insects were difficult to capture on Diuris maculata due to the very low frequency and short duration of visits. More pollinaria were removed from the flowers than pollinia deposited. Pollen loads carried by insects bearing orchid pollinia were almost exclusively from Daviesia spp. and Pultenaea scabra. These data, together with the morphological similarity of the flowers of D. maculata to those of Daviesia spp. and Pultenaea scabra, indicate that the orchid attracts pollinators by floral mimicry.
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Indsto, James O., Peter H. Weston, Mark A. Clements, Adrian G. Dyer, Michael Batley, and Robert J. Whelan. "Pollination of Diuris maculata (Orchidaceae) by male Trichocolletes venustus bees." Australian Journal of Botany 54, no. 7 (2006): 669. http://dx.doi.org/10.1071/bt05146.
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In a previous study, the Australian terrestrial orchid Diuris maculata sensu lato, from a site near Melbourne in Victoria, was suggested to be a floral mimic of several sympatric legume species. The widespread distribution of this orchid species (or species complex) suggests that there may be a number of different model and pollinator species throughout this range, and that additional studies are necessary to characterise its pollination adequately. In this study, the pollination of D. maculata in the Sydney region, mainly at Scheyville National Park, was compared with the results previously obtained in Victoria. At Scheyville National Park, Trichocolletes venustus was the only native bee species found in significant numbers, and the flowers it visited were almost exclusively the legumes Hardenbergia violacea and Daviesia ulicifolia ssp. ulicifolia. Fifty per cent (14 of 28) of captured male bees carried D. maculata orchid pollinaria, or remnants, which were identified by AFLP fingerprinting. Female bees, which appeared about 10–14 days after males, were not observed visiting the orchid or carrying orchid pollinaria. We confirmed that D. maculata flowers lack nectar, and noted that the pea-like flowers possess an UV false nectar guide comparable to the true UV nectar guide of the legume flowers. Colorimetric analysis showed the colour separation between D. ulicifolia ssp. ulicifolia and the orchid is small enough to be likely to produce foraging errors, consistent with mimicry. We conclude that guild mimicry of a diversity of ‘egg and bacon’ legumes best explains the pollination of D. maculata s.l., rather than precise mimicry of any one pea species. Preliminary observations suggest that pea-flower mimicry may range from being highly precise in some species, through to being much more generalised, but still retaining elements of mimicry. The novel finding of comparable UV patterns in Diuris species and putative pea models applies to most species in the genus and we found that the rare D. aequalis shows remarkable similarity in colour, shape and UV patterns to the sympatric legume Gompholobium huegelii, and is likely to be a mimic of this species.
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DeFrank*, Joe, and James J. K. Leary. "The Response of Potted Orchids to Sequential Postemergence Herbicide Applications in Hawaii." HortScience 39, no. 4 (July 2004): 844E—845. http://dx.doi.org/10.21273/hortsci.39.4.844e.
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Two experiment were conducted in 1999 and 2000 to determine the response of orchid cultivars, grown as potted plants, to postemergence herbicides. In a film covered commercial nursery in Pahoa, four orchid cultivars were exposed to five sequential herbicide applications. The cultivars used were: Emma White (Dendrobium), Wildcat Blood Ruby, Volcano Queen (both Oncidiums), and SuFun Beauty (Vanda). The herbicides evaluated in this experiment were diuron and clopyralid applied at the anticipated (1×), 2×, and 4× use rate. Spray applications were made directly to crop foliage using a spray to wet application. The first application was applied on 11 Nov. 1999 with sequential applications made at 20-, 208-, 73-, and 69-day intervals for a total of five sprays. Orchid dry weight accumulation was not significantly reduced and all cultivars responded in a similar way. “Emma White” was the only cultivar to express abnormal growth to clopyralid in the form of J-shaped flower spikes and deformed flowers. The other three cultivars did not show any noticeable injury in response to any of the spray applications. A follow up experiment was conducted on the dry leeward coast of Oahu in a commercial saran house. Diuron was the only herbicide evaluated at one and four times the anticipated labeled use rate. The first application was made on 27 Apr. 2000 with sequential applications made at 50-, 21-, 70-, and 66-day intervals for a total of five sprays. The orchids selected for this experiment included nine Dendrobiums and one Vanda. Treatments were made directly to plant foliage using a spray to wet application. Whole plant dry weight accumulation of the 10 cultivars responded in a similar way and no herbicide treatment reduced dry weight accumulation in comparison to untreated plants.
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Collins, MT, and KW Dixon. "Micropropagation of an Australian terrestrial orchid Diuris longifolia R. Br." Australian Journal of Experimental Agriculture 32, no. 1 (1992): 131. http://dx.doi.org/10.1071/ea9920131.
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A method is described for the in vitro propagation of the Australian terrestrial orchid Diuris longifolia R. Br. Explants from inflorescences of D. longifolia were successfully cultured on modified Burgeffs N3f containing the cytokinin N6 benzyladenine. Protocorm-like bodies formed after 49 days on explants taken from the basal section of flower buds and axillary nodes from inflorescences. Root formation occurred 70 days after transfer of 10-20-rnm-long shoots onto medium containing coconut water and no cytokinin, and rooted plantlets were transferred to soil and acclimatised 2-3 weeks later. Rooting of in vitro shoots was improved by increasing the sucrose concentration to 40 g/L or by addition of 0.05% activated charcoal to the culture medium. Plantlets developed flowering stems in vitro and flowered in pots 11 months after excision of explants from the parent plant. This tissue culture method has been successfully applied to the propagation of D. purdiei, a rare and threatened species from Western Australia.
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Indsto, James O., Peter H. Weston, and Mark A. Clements. "A molecular phylogenetic analysis of Diuris (Orchidaceae) based on AFLP and ITS reveals three major clades and a basal species." Australian Systematic Botany 22, no. 1 (2009): 1. http://dx.doi.org/10.1071/sb08029.
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Diuris is a terrestrial orchid genus of at least 61 and possibly more than 100 species, restricted to Australia except for one species endemic in Timor. Distinctive species groups have respective eastern and western centres of distribution. Although species affinities have been vaguely understood for many years, no formal infrageneric treatment has been undertaken as Diuris possesses few reliable morphological characters for a classification system. We have undertaken cladistic parsimony and Bayesian phylogenetic analyses of Diuris by using the ITS1–5.8S–ITS2 region of nuclear rDNA and morphological characters, with a subset of samples also studied by amplified fragment length polymorphism (AFLP) as an independent test of phylogenetic relationships. Four major clades with strong bootstrap support were resolved and are named here according to a recently published classification; D. sulphurea forms a lineage (subg. Paradiuris) of its own that is well supported as the sister to the rest of Diuris. Two other major eastern clades contained species related to D. maculata (subg. Xanthodiuris) and D. punctata (subg. Diuris), respectively. Although these latter two subgenera are genetically well resolved, there is minimal genetic variation at species level, consistent with recent, rapid speciation. A fourth clade (subg. Hesperodiuris) has a centre of distribution in Western Australia, and has more genetic and morphological variation than the eastern subgenera. Total evidence analysis provides support for the western clade being sister group to the two eastern subgenera Diuris and Xanthodiuris; however, this relationship was not resolved by molecular data. Hybridisation is known to be common among species within subgenera Diuris and Xanthodiuris. Instances of incongruence between different datasets were found suggestive of hybridisation events between species of different sections of Diuris.
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Smith, Zoë F., Elizabeth A. James, and Cassandra B. McLean. "Mycorrhizal specificity of Diuris fragrantissima (Orchidaceae) and persistence in a reintroduced population." Australian Journal of Botany 58, no. 2 (2010): 97. http://dx.doi.org/10.1071/bt09214.
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This study investigated the diversity and specificity of mycorrhizal fungi associated with five Diuris (Orchidaceae) taxa in south-eastern Australia, as part of a reintroduction program for the endangered species Diuris fragrantissima. We compared fungi isolated from D. fragrantissima occurring naturally in the only remaining population with those from artificially cultivated plants and reintroduced plants 18 months after planting in a new field site west of Melbourne. Genetic similarity of nuclear internal transcribed spacer and nuclear large subunit DNA sequences showed that Diuris taxa associate with a narrow taxonomic range of fungi within the cosmopolitan family Tulasnellaceae in the Rhizoctonia alliance. All fungal isolates induced host seed germination and hence were considered mycorrhizal. Fungal isolates from naturally occurring D. fragrantissima plants showed a higher level of genetic similarity than fungi isolated from cultivated plants. This observation suggests that, historically, the species may have associated with a more genetically variable range of Tulasnella fungi. Artificially cultivated D. fragrantissima were propagated aseptically from seed and spontaneously formed mycorrhizal associations within 6 months of transfer to potting media. Wild collected D. fragrantissima plants maintained in cultivation for over 30 years were found to contain mycorrhizal fungi similar to those isolated from naturally occurring plants in 2004–2006. Mycorrhizal associations in artificially cultivated D. fragrantissima were present in 18 randomly sampled plants 18 months after reintroduction. Further, associations formed between several reintroduced plants and a fungus concurrently inoculated into site soil. We propose that future orchid reintroductions may benefit from the concurrent addition of suitable mycorrhizal fungi to site soil. Maintenance of orchid mycorrhizal relationships after reintroduction is essential to improve long-term viability of reintroduced populations.
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Indsto, James O., Peter H. Weston, Mark A. Clements, and Robert J. Whelan. "Highly sensitive DNA fingerprinting of orchid pollinaria remnants using AFLP." Australian Systematic Botany 18, no. 3 (2005): 207. http://dx.doi.org/10.1071/sb04009.
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Numerous Australian terrestrial orchid species in the genus Diuris may be pollinated by food source mimicry. In our field studies, direct observations of orchid–pollinator interactions were rare, but native bees were frequently captured carrying orchid pollinaria, or pollinaria remnants. Sometimes, pollinaria remnants were minimal and included only the viscidium, a sticky pad that was often highly persistent. Confirmation of such tissue as being of orchid source, and attributing them to a particular species can aid pollination studies. DNA-based methods that may identify more or less intact orchid pollinaria are available, but extremely small and degraded samples can pose technical challenges. We have developed an AFLP protocol for such difficult samples that offers some significant advantages over direct PCR-based analysis. We simulated AFLP profiling of very low-DNA samples using DNA template from serial dilutions. A DNA sample range from 6.4 picograms to at least as high as 100 nanograms (15 500-fold range) all yielded AFLP fingerprints. The practical application of this inherent sensitivity of AFLP is demonstrated by the identification of remnants of orchid pollinaria sampled from bees, presented here as a case study. It is expected that this approach will find many applications where sample DNA is limiting, or possibly where pollen of similar appearance may comprise species mixtures.
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Smith, Zoë F., Elizabeth A. James, Mark J. McDonnell, and Cassandra B. McLean. "Planting conditions improve translocation success of the endangered terrestrial orchid Diuris fragrantissima (Orchidaceae)." Australian Journal of Botany 57, no. 3 (2009): 200. http://dx.doi.org/10.1071/bt09072.
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By conducting reintroductions of the endangered terrestrial orchid Diuris fragrantissima D.L.Jones & M.A.Clem. we compared planting at the following three stages of the natural perennial growth cycle: as actively growing symbiotic plants in spring and autumn and as dormant tubers in summer. Plants reintroduced in spring and autumn were incorporated into randomised treatments involving soil aeration and addition of a mycorrhizal fungus. The addition of a mycorrhizal fungus and soil aeration together significantly increased survival and flowering of plants reintroduced in spring, whereas they had no significant effect on plants reintroduced in autumn. Addition of a fungus without soil aeration did not improve plant survival or flowering. Reintroducing actively growing plants was more successful than reintroducing dormant tubers, with 32.5% and 29.1% plants (reintroduced in spring and autumn, respectively) and 11.0% of tubers persisting after 4 years. Although survival of reintroduced plants declined at a rate of 16.9% per year for 4 years following reintroduction, survival of remnant plants remained relatively constant, ranging from 80.0 to 93.0%. Tuber size was positively correlated with survival and flowering of reintroduced plants for 2 years following reintroduction. A general trend was observed towards the increased likelihood of re-emergence and flowering of plants that flowered in previous seasons.
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Indsto, James O., Peter H. Weston, Mark A. Clements, and Robert J. Whelan. "Corrigendum to: Highly sensitive DNA fingerprinting of orchid pollinaria remnants using AFLP." Australian Systematic Botany 18, no. 5 (2005): 473. http://dx.doi.org/10.1071/sb04009_co.
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Numerous Australian terrestrial orchid species in the genus Diuris may be pollinated by food source mimicry. In our field studies, direct observations of orchid.pollinator interactions were rare, but native bees were frequently captured carrying orchid pollinaria, or pollinaria remnants. Sometimes, pollinaria remnants were minimal and included only the viscidium, a sticky pad that was often highly persistent. Confirmation of such tissue as being of orchid source, and attributing them to a particular species can aid pollination studies. DNA-based methods that may identify more or less intact orchid pollinaria are available, but extremely small and degraded samples can pose technical challenges. We have developed an AFLP protocol for such difficult samples that offers some significant advantages over direct PCR-based analysis. We simulated AFLP profiling of very low-DNA samples using DNA template from serial dilutions. A DNA sample range from 6.4 picograms to at least as high as 100 nanograms (15�500-fold range) all yielded AFLP fingerprints. The practical application of this inherent sensitivity of AFLP is demonstrated by the identification of remnants of orchid pollinaria sampled from bees, presented here as a case study. It is expected that this approach will find many applications where sample DNA is limiting, or possibly where pollen of similar appearance may comprise species mixtures.
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Scaccabarozzi, Daniela, Lorenzo Guzzetti, Ryan D. Phillips, Lynne Milne, Nicola Tommasi, Salvatore Cozzolino, and Kingsley W. Dixon. "Ecological factors driving pollination success in an orchid that mimics a range of Fabaceae." Botanical Journal of the Linnean Society 194, no. 2 (August 5, 2020): 253–69. http://dx.doi.org/10.1093/botlinnean/boaa039.
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Abstract Rewarding plants can enhance the pollination success of co-occurring plants pollinated by food mimicry. However, it is not always possible to readily discern between the effect of model and magnet species. Here, we tested for mimicry of co-occurring Fabaceae by the rewardless Diuris magnifica (Orchidaceae) and whether the number of flowers of Fabaceae, habitat remnant size and frequency of conspecifics, influenced the pollination success of D. magnifica. Trichocolletes bees were the primary pollinators of D. magnifica, on which they displayed similar behaviour as seen when feeding on Fabaceae. Quantification of spectral reflectance suggested that flowers of Bossiaea eriocarpa, Daviesia divaricata and Jacksonia sternbergiana may represent models for D. magnifica, whereas Hardenbergia comptoniana strongly differed in colour. Orchid pollination success was not directly affected by the number of model flowers, but the pollination rate was enhanced by increased numbers of Hardenbergia flowers. Pollination success of the orchid decreased with higher density of conspecifics, but did not exhibit a significant relationship with Trichocolletes occurrence, possibly because of the contribution of sub-optimal pollinator species. Fruit set of the orchid was greater in larger habitat remnants. Overall, pollination success of D. magnifica is affected by ecological factors related to the effectiveness of mimicry, numbers of co-flowering plants and anthropogenic landscape alteration.
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Bell, Stephen A. J. "Successful recruitment following translocation of a threatened terrestrial orchid ( Diuris tricolor ) into mining rehabilitation in the Hunter Valley of NSW." Ecological Management & Restoration 22, no. 2 (April 10, 2021): 204–7. http://dx.doi.org/10.1111/emr.12473.
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Derr, Jeffrey F. "Biological Assessment of Herbicide Use in Apple Production II. Estimated Impacts following Loss of Specific Herbicides." HortTechnology 11, no. 1 (January 2001): 20–25. http://dx.doi.org/10.21273/horttech.11.1.20.
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Assessing herbicide impacts are difficult due to the indirect effects of weeds on apple (Malus domestica Borkh) growth and development. Herbicide loss will increase potential for development of herbicide-resistant weeds. A limited number of alternatives exist for herbicides currently used in apple production. Switching to certain herbicides increases potential for crop injury. Certain alternatives have higher acute toxicity or are more expensive. No alternatives exist to 2,4-D for broadleaf control in grass alleyways. Nonselective herbicides are alternatives to 2,4-D within the row but pose a greater risk of crop injury. It is difficult to assess long-term impact of 2,4-D loss due to impact on pollination and pest management. Loss of glyphosate will result in yield losses in apple production. Most alternatives to glyphosate are less effective on perennial weed species. Paraquat, one alternative to glyphosate, poses greater hazard to the applicator due to its higher acute toxicity. Diuron is important for rotation with simazine to prevent the development of herbicide-resistance weeds. Norflurazon has an important use in recently planted orchards, where few alternatives exist for yellow nutsedge (Cyperus esculentus L.) control. Oryzalin is commonly used for newly planted orchards and certain alternatives can only be used on nonbearing trees. Alternatives to paraquat pose greater risk of tree injury, although there would be increased worker safety with alternative products. Glyphosate would be the predominate alternative if paraquat was no longer available. Simazine would be the predominate replacement if diuron were no longer available and diuron would be the predominant alternative if simazine was no longer registered for use. Resistance management would be negatively impacted if growers relied on simazine or diuron as their primary preemergence herbicide.
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D. Lunt, Ian. "Variation in flower production of nine grassland species with time since fire, and implications for grassland management and restoration." Pacific Conservation Biology 1, no. 4 (1994): 359. http://dx.doi.org/10.1071/pc940359.
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The impact of time since fire on flower production was examined in a temperate Themeda triandra grassland in Gippsland, Victoria. Flower production by nine species (Arthropodium strictum, Bulbine bulbosa, Burchardia umbellata, Chrysocephalum apiculatum, Craspedia variabilis, Diuris punctata, Helichrysum scorpioides, Leptorhynchos squamatus and Pimelea humilis) was compared between areas burnt six months and two years previously. Thick grass in the area burnt two years previously inhibited flowering by most species. All species except C. apiculatum and D. punctata flowered most abundantly in the area burnt six months earlier, and flower production by B. bulbosa, A. strictum and C. variabilis was largely restricted to that area. There were over 100 times as many flowering plants of B. bulbosa in the most recently burnt area. C. apiculatum produced similar quantities of flowers in both zones, but D. punctata countered the general pattern for greater flower production in the most recently burnt area by flowering most abundantly in the area burnt two years previously. Some of the species studied form transient seed banks, so maximum recruitment may be attained by burning sites the year immediately after a season of high flower production, rather than delaying burning until later years, when little flowering occurs and few seeds are present for recruitment. Annual autumn burning could eliminate the threatened orchid, D. punctata.
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De Prado, Rafael, Carmen Dominguez, and Manuel Tena. "Characterization of Triazine-Resistant Biotypes of Common Lambsquarters (Chenopodium album), Hairy Fleabane (Conyza bonaeriensis), and Yellow Foxtail (Setaria glauca) Found in Spain." Weed Science 37, no. 1 (January 1989): 1–4. http://dx.doi.org/10.1017/s0043174500055752.
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Triazine-resistant (R) biotypes of common lambsquarters, yellow foxtail, and hairy fleabane were found in the Province of Córdoba (Andalusia, Southern Spain). The former two R biotypes came from atrazine-treated cornfields, whereas the latter came from simazine-treated nontilled olive orchards. The R biotypes of common lambsquarters and yellow foxtail and the R biotype of hairy fleabane survived at doses up to 5 kg ai/ha of soil-applied atrazine or simazine, respectively. Photosynthetic electron transport in R biotypes was unaffected by atrazine and simazine but was inhibited by diuron, as shown by fluorescence induction measurements in whole leaves. In Hill reaction assays, the R biotypes showed high resistance to atrazine and simazine (resistance factors in the range of 350 to 550), medium to high resistance to ametryn, terbumeton, metribuzin, and monolinuron (resistance factors in the range of 80 to 250), slight resistance to diuron and methabenzthiazuron (resistance factors in the range of 1.1 to 15.7), and reverse resistance to swep, ioxynil, and DNOC (resistance factors less than 1). It is concluded that the R biotypes have a chloroplast mode of resistance similar to that previously described for other triazine-resistant weed biotypes.
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Rouchaud, J., O. Neus, R. Bulcke, K. Cools, H. Eelen, and T. Dekkers. "Soil Dissipation of Diuron, Chlorotoluron, Simazine, Propyzamide, and Diflufenican Herbicides After Repeated Applications in Fruit Tree Orchards." Archives of Environmental Contamination and Toxicology 39, no. 1 (June 30, 2000): 60–65. http://dx.doi.org/10.1007/s002440010080.
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Pérez-López, Macrina, Fidel González-Torralva, Hugo Cruz-Hipólito, Francisco Santos, José A. Domínguez-Valenzuela, and Rafael De Prado. "Characterization of Glyphosate-Resistant Tropical Sprangletop (Leptochloa virgata) and Its Alternative Chemical Control in Persian Lime Orchards in Mexico." Weed Science 62, no. 3 (September 2014): 441–50. http://dx.doi.org/10.1614/ws-d-13-00177.1.
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Field, greenhouse, and laboratory experiments were conducted to investigate resistance to glyphosate in tropical sprangletop biotypes (Lv8 and Lv9) collected in Persian lime from Veracruz, Mexico. Assays to determine the dose required to reduce seedling fresh weight by 50% indicated a resistance factor (RF) of 4.9 and 3.2 for biotypes Lv8 and Lv9, respectively; whereas the LD50showed a RF of 4.4 and 3.3 for biotypes Lv8 and Lv9, respectively. On the other hand, the RFs using whole plant dose–response assays were lower (RF of 3 for Lv8 and 2.3 for Lv9). The susceptible biotype (LvS) accumulated 5.5 and 11.8 times more shikimate than biotypes Lv8 and Lv9, respectively, at 96 h after treatment (HAT). In field experiments, alternatives to glyphosate-resistant tropical sprangletop management were identified. Indaziflam + glufosinate and paraquat + diuron provided over 80% control of in-field populations of tropical sprangletop at 60 d after treatment (DAT). These results confirmed the first reported case of glyphosate-resistant tropical sprangletop.
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Grey, Timothy L., Fred S. Turpin, Lenny Wells, and Theodore M. Webster. "A Survey of Weeds and Herbicides in Georgia Pecan." Weed Technology 28, no. 3 (September 2014): 552–59. http://dx.doi.org/10.1614/wt-d-13-00126.1.
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A survey was conducted in 2012 in Georgia to determine the most troublesome weeds in pecan orchards and document common herbicide weed control practices. Weed control practices and infestations in pecan were divided between winter and summer seasons. The most troublesome pecan winter weed species were wild radish and Italian ryegrass, whereas the most troublesome summer season weeds were Palmer amaranth and bermudagrass. Other weeds included crabgrass species, bahiagrass, Florida pusley, purslane species, morningglory species, curly dock, and cutleaf evening-primrose. The most widely used POST herbicide in both the winter and summer season was glyphosate. The most commonly used year-round herbicides with soil persistence were pendimethalin, diuron, flumioxazin, halosulfuron, simazine, indaziflam, and oryzalin. Use of multiple herbicides, PRE- and POST-contact and soil-persistent, with various herbicide mechanisms of action, have benefited pecan producers by providing year-round weed control, despite herbicide-resistant weeds being widely established in this region.
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Ramirez, Analiza Henedina M., Amit J. Jhala, and Megh Singh. "Efficacy of PRE and POST Herbicides for Control of Citron Melon (Citrullus lanatusvar.citroides)." Weed Technology 26, no. 4 (December 2012): 783–88. http://dx.doi.org/10.1614/wt-d-12-00063.1.
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Citron melon is a monoecious and hairy annual vine commonly found in citrus orchards and cotton and peanut fields. There is limited information available on citron melon control with PRE- and POST-applied herbicides in Florida citrus. Experiments were conducted to evaluate the response of citron melon to 11 PRE and 18 POST herbicides under greenhouse conditions. Indaziflam applied PRE at 0.095 kg ai ha−1resulted in 13% citron melon emergence at 14 d after treatment (DAT). The majority of PRE herbicides did not affect emergence at 14 DAT. Efficacy of PRE herbicides at 21 DAT resulted in > 90% control of citron melon with bromacil, premix formulation of bromacil + diuron, flumioxazin, indaziflam at 0.073 and 0.095, norflurazon, and simazine. Citron melon control was < 30% 21 DAT following PRE-applied diuron, oryzalin, and flazasulfuron. Control of citron melon varied by POST herbicides and growth stage. Regardless of citron melon growth stage, glyphosate, glufosinate, saflufenacil, paraquat, and flumioxazin provided > 90% at 7 and 14 DAT. Carfentrazone, flazasulfuron, imazapic, pyrithiobac-Na, rimsulfuron, trifloxysulfuron, and premix of 2,4-D + glyphosate controlled citron melon at least 90% when applied to two- to four-leaf plants. Control was reduced when application was delayed to the six- to eight-leaf stage. Bentazon and halosulfuron controlled citron melon 11 to 31% regardless of growth stage. Biomass of citron melon at 14 DAT was reduced > 50% in all herbicide treatments except with bentazon and halosulfuron applied at both stages, and dicamba, mesotrione, imazapic, and rimsulfuron applied to six- to eight-leaf citron melon. The results of this study indicate that citron melon can be adequately controlled with several PRE- or POST-applied herbicides; however, research is required to evaluate PRE followed by POST programs or their tank mixtures for season-long control of citron melon under field conditions.
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Smith, Zoe, Elizabeth James, and Cassandra McLean. "Finding a mycorrhizal fungus for reintroductions of the threatened terrestrial orchid Diuris fragrantissima." Lankesteriana 7, no. 1-2 (June 17, 2015). http://dx.doi.org/10.15517/lank.v7i1-2.19570.
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Australian terrestrial orchids rely on associations with suitable mycorrhizal fungi for in situ seed germi- nation and establishment, an important prerequisite for self sustaining populations. Finding an appropri- ate mycorrhizal fungus is therefore imperative to suc- cessful reintroductions. Reintroductions have been planned to conserve the terrestrial orchid Diuris fra- grantissima, which is Critically Endangered in Victoria, Australia, having been reduced to less than 25 plants at a single site.
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Davis, Belinda, Wei-Han Lim, Hans Lambers, Kingsley W. Dixon, and David J. Read. "Inorganic phosphorus nutrition in green-leaved terrestrial orchid seedlings." Annals of Botany, March 5, 2022. http://dx.doi.org/10.1093/aob/mcac030.
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Abstract Background and Aims Many terrestrial orchids have an obligate dependence on their mycorrhizal associations for nutrient acquisition, particularly during germination and early seedling growth. Though important in plant growth and development, phosphorus (P) nutrition studies in mixotrophic orchids have been limited to only a few orchid species and their fungal symbionts. For the first time, we demonstrate the role of a range of fungi in the acquisition and transport of inorganic P to four phylogenetically distinct green-leaved terrestrial orchid species (Diuris magnifica, Disa bracteata, Pterostylis sanguinea and Microtis media subsp. media) that naturally grow in P-impoverished soils. Methods Mycorrhizal P uptake and transfer to orchids was determined and visualized using agar microcosms with a diffusion barrier between P source (33P orthophosphate) and orchid seedlings, allowing extramatrical hyphae to reach the source. Key Results Extramatrical hyphae of the studied orchid species were effective in capturing and transporting inorganic P into the plant. Following 7 d of exposure, between 0.5 % (D. bracteata) and 47 % (D. magnifica) of the P supplied was transported to the plants (at rates between 0.001 and 0.097 fmol h−1). This experimental approach was capable of distinguishing species based on their P-foraging efficiency, and highlighted the role that fungi play in P nutrition during early seedling development. Conclusions Our study shows that orchids occurring naturally on P-impoverished soils can obtain significant amounts of inorganic P from their mycorrhizal partners, and significantly more uptake of P supplied than previously shown in other green-leaved orchids. These results provide support for differences in mycorrhiza-mediated P acquisition between orchid species and fungal symbionts in green-leaved orchids at the seedling stage. The plant–fungus combinations of this study also provide evidence for plant-mediated niche differentiation occurring, with ecological implications in P-limited systems.
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Smith, Zoe, Elizabeth James, and Cassandra McLean. "Experimental reintroduction of the threatened terrestrial orchid Diuris fragrantissima." Lankesteriana 7, no. 1-2 (June 17, 2015). http://dx.doi.org/10.15517/lank.v7i1-2.19569.
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Diuris fragrantissima D. L. Jones et M. A. Clem. is a perennial terrestrial orchid endemic to the state of Victoria, Australia. The species is listed as Critically Endangered in Victoria under the criteria of the International Union for the Conservation of Nature and Natural Resources (IUCN), having suf- fered a severe population decline since the 1930s, largely attributable to habitat destruction for agricul- tural and urban development.
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"Micropropagation of an Australian terrestrial orchid Diuris longifolia R. Br." Biological Conservation 66, no. 2 (1993): 147. http://dx.doi.org/10.1016/0006-3207(93)90154-s.
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Martín-Forés, I., S. L. Bywaters, B. Sparrow, and G. R. Guerin. "Orchid fruiting success is unrelated to surrounding floral resources in South Australian plant communities." Journal of Plant Ecology, July 31, 2022. http://dx.doi.org/10.1093/jpe/rtac074.
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Abstract To maintain recruitment in orchid populations in an ecosystem setting, we must understand how surrounding floral resources affect fruiting success. We studied fruiting success in two endemic Australian species, Diruis pardina and Glossodia major, in relation to surrounding floral resources. Diuris pardina has a visually deceptive pollination strategy via mimicry of pea flowers, attracting pollinators associated with co-flowering plants of Pultenaea. Glossodia major displays dummy anthers and has a more generalist pollination strategy. We expected fruiting success of both species to positively correlate to conspecific and heterospecific floral density because orchid pollination should be enhanced by the attraction of higher densities of native bees. We expected fruiting success of D. pardina to positively correlate with abundance of Pultenaea flowers. Surveying 18 plots in South Australia, we counted species, individuals and flowers of conspecifics and heterospecifics and returned to count flowers that set fruit. We conducted Pearson correlations between fruiting success and density of conspecific flowers, richness, abundance and Shannon index of surrounding floral resources and floral abundance of individual species. Fruiting success was correlated with conspecific floral density for Diuris pardina but not G. major. No relationship was found between fruiting success and heterospecific floral resources. Fruiting success of D. pardina was not correlated with abundance of Pultenaea; instead it was positively correlated with the invasive species Lavandula stoechas.
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Lunau, Klaus, Daniela Scaccabarozzi, Larissa Willing, and Kingsley Dixon. "A bee’s eye view of remarkable floral colour patterns in the south-west Australian biodiversity hotspot revealed by false colour photography." Annals of Botany, July 3, 2021. http://dx.doi.org/10.1093/aob/mcab088.
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Abstract Background and Aims Colour pattern is a key cue of bee attraction selectively driving the appeal of pollinators. It comprises the main colour of the flower with extra fine patterns, indicating a reward focal point such as nectar, nectaries, pollen, stamens and floral guides. Such advertising of floral traits guides visitation by the insects, ensuring precision in pollen gathering and deposition. The study, focused in the Southwest Australian Floristic Region, aimed to spot bee colour patterns that are usual and unusual, missing, accomplished by mimicry of pollen and anthers, and overlapping between mimic-model species in floral mimicry cases. Methods Floral colour patterns were examined by false colour photography in 55 flower species of multiple highly diverse natural plant communities in south-west Australia. False colour photography is a method to transform a UV photograph and a colour photograph into a false colour photograph based on the trichromatic vision of bees. This method is particularly effective for rapid screening of large numbers of flowers for the presence of fine-scale bee-sensitive structures and surface roughness that are not detectable using standard spectrophotometry. Key Results Bee- and bird-pollinated flowers showed the expected but also some remarkable and unusual previously undetected floral colour pattern syndromes. Typical colour patterns include cases of pollen and flower mimicry and UV-absorbing targets. Among the atypical floral colour patterns are unusual white and UV-reflecting flowers of bee-pollinated plants, bicoloured floral guides, consistently occurring in Fabaceae spp., and flowers displaying a selective attractiveness to birds only. In the orchid genera (Diuris and Thelymitra) that employ floral mimicry of model species, we revealed a surprising mimicry phenomenon of anthers mimicked in turn by model species. Conclusion The study demonstrates the applicability of ‘bee view’ colour imaging for deciphering pollinator cues in a biodiverse flora with potential to be applied to other eco regions. The technique provides an exciting opportunity for indexing floral traits on a biome scale to establish pollination drivers of ecological and evolutionary relevance.