In situ symbiotic seed germination and propagation of terrestrial orchid seedlings for establishment at field sites

2006 ◽  
Vol 54 (4) ◽  
pp. 375 ◽  
Author(s):  
A. L. Batty ◽  
M. C. Brundrett ◽  
K. W. Dixon ◽  
K. Sivasithamparam
Keyword(s):  
Mycorrhizal Fungi ◽  
Seedling Survival ◽  
Natural Habitat ◽  
Survival Rates ◽  
Growing Season ◽  
Individual Species ◽  
Symbiotic Germination ◽  
Terrestrial Orchids ◽  
Eucalypt Woodland

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.

New methods to improve symbiotic propagation of temperate terrestrial orchid seedlings from axenic culture to soil

2006 ◽  
Vol 54 (4) ◽  
pp. 367 ◽  
Author(s):  
A. L. Batty ◽  
M. C. Brundrett ◽  
K. W. Dixon ◽  
K. Sivasithamparam
Keyword(s):  
Mycorrhizal Fungi ◽  
Seedling Survival ◽  
Axenic Culture ◽  
Leaf Size ◽  
Petri Dish ◽  
Terrestrial Orchid ◽  
Symbiotic Germination ◽  
Root Tuber ◽  
Terrestrial Orchids ◽  
Summer Dormancy

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.

scholarly journals A Proposed Framework for Efficient and Cost-Effective Terrestrial Orchid Conservation

2020 ◽  
Author(s):  
Mark Brundrett
Keyword(s):  
Mycorrhizal Fungi ◽  
Habitat Management ◽  
Wild Plants ◽  
Sterile Culture ◽  
Seed Collection ◽  
Orchid Conservation ◽  
Symbiotic Germination ◽  
Terrestrial Orchids ◽  
Conservation Projects

This paper presents a comprehensive and adaptive framework for orchid conservation programs illustrated with data from published and unpublished case studies. There is a specific focus on West Australian terrestrial orchids, but many of the approaches have universal relevance. Aspects of the framework include (1) setting appropriate objectives, (2) establishing effective collaborations between scientists, volunteers and regulators to fill knowledge and funding gaps, (3) use of survey and demographics data to determine extinction risks and management requirements for species, (4) effective habitat management to overcome threats such as grazing, (5) finding potential new habitats by modelling climate and site data, (6) investigating the effectiveness of pollinators and (7) using seed baiting to detect mycorrhizal fungi. The relative cost and effectiveness of different methods used to propagate orchids for translocation are compared. Methods known to be successful, in order of complexity, include placement of seed in situ, vegetative propagation, symbiotic germination in non-sterile organic matter, symbiotic germination in sterile culture, asymbiotic sterile germination and clonal division in tissue culture. These form a continuum of complexity, cost, time required, faculties needed, as well as the capacity to maintain genetic diversity and produce seedlings preadapted to survive in situ. They all start with seed collection and lead to seed storage, living collections used as tuber banks and seed orchards, as well as translocation for conservation. They could also lead to commercial availability and sustainable ecotourism, both of which are needed to reduce pressure on wild plants. Overall, there has been a strong preference to use relatively complex, expensive and time-consuming methods for orchid conservation, despite evidence that simpler approaches have also been successful. These simpler methods, which include in situ seed placement and non-sterile germination on inorganic substrates, should be trialled in combination with more complex orchid propagation methods as part of an adaptive management framework. It is essential that orchid conservation projects harness the unique biological features of orchids, such as abundant seed production and mycorrhizal fungi which are far more widespread than their hosts. This is necessary to increase the efficiency and coverage of recovery actions for the largest and most threatened plant family.

scholarly journals Symbiotic germination of threatened Australian terrestrial orchids and the effect of nursery potting media on seedling survivals

Lankesteriana ◽  
2015 ◽  
Vol 7 (1-2) ◽  
Author(s):  
Magali Wright ◽  
Zoe Smith ◽  
Richard Thomson ◽  
Rob Cross
Keyword(s):  
Research And Development ◽  
Mycorrhizal Fungi ◽  
Ex Situ ◽  
Symbiotic Germination ◽  
Terrestrial Orchids ◽  
Potting Media ◽  
Victorian Department ◽  
The University

Since the early 1990s, the RBG has contributed to the conservation of Victoria’s Endangered orchids through its ex situ propagation program. Working cooperatively with the Victorian Department of Sustainability and Environment (DSE), the Melbourne Zoo, the Australasian Native Orchid Society, The University of Melbourne, RMIT University and Parks Victoria, research and development has lead to a greater understanding of Victoria’s terrestrial orchids and their associated mycorrhizal fungi, and assisted in the implementation of Recovery Plans. 

Occurrence of Vesicular Mycorrhizal Fungi in Dryland Species of Restionaceae and Cyperaceae From South-West Western Australia

1993 ◽  
Vol 41 (6) ◽  
pp. 733 ◽  
Author(s):  
KA Meney ◽  
KW Dixon ◽  
M Scheltema ◽  
JS Pate
Keyword(s):  
Western Australia ◽  
Soil Profile ◽  
Mycorrhizal Fungi ◽  
Natural Habitat ◽  
Growing Season ◽  
Early Winter ◽  
Mycorrhizal Infection ◽  
South West ◽  
Vesicular Arbuscular ◽  
Va Mycorrhizal Fungi

Species of Cyperaceae and Restionaceae were examined for presence of vesicular-arbuscular (VA) mycorrhizal fungi in natural habitat in south-west Western Australia. VA mycorrhizal fungi were detected in roots of two species of Cyperaceae (Lepidosperma gracile and Tetraria capillaris), and two species of Restionaceae (Alexgeorgea nitens and Lyginia barbata), all representing the first records for these genera. Results indicated a very short seasonal period of infection, with VA mycorrhizal fungi representing the genera Acaulospora, Glomus, Scutellospora and Gigaspora identified in roots. VA mycorrhizal fungi were prominent from late autumn to early winter (April-June) and in up to 30% of the young, new season's roots as they penetrated the upper 10 cm region of the soil profile. Mycorrhizal infection was not evident during the dry summer months. This study suggests that mycorrhizas may be important for nutrition of these hosts in these environments but their activity is restricted to a brief period of the growing season.

Introduction, growth and persistence in situ of orchid mycorrhizal fungi

2007 ◽  
Vol 55 (6) ◽  
pp. 665 ◽  
Author(s):  
Penelope S. Hollick ◽  
Jen A. McComb ◽  
Kingsley W. Dixon
Keyword(s):  
Seed Germination ◽  
Mycorrhizal Fungi ◽  
Mycorrhizal Fungus ◽  
Growing Season ◽  
Summer Drought ◽  
Orchid Species ◽  
The Third ◽  
Orchid Mycorrhizal Fungi ◽  
Germination And Growth

The introduction, growth and persistence of orchid mycorrhizal fungi in situ were studied by using a seed-baiting method. A mycorrhizal fungus from the carousel spider orchid, Caladenia arenicola (Hopper & A.P.Br.), was introduced to sites within an area from which the orchid and fungus were absent, adjacent to a natural population of C. arenicola. In the first growing season, the fungus grew up to 50 cm from its introduction point, usually persisted over the summer drought into the second season and even into the third season, stimulating germination and growth to tuber formation of the seeds in the baits. Watering the inoculated areas significantly increased seed germination. This suggests that it is possible to reintroduce the mycorrhizal fungi either before or together with seeds of orchid species needing re-establishment in an area.

Orchidaceous rhizoctonias in pot cultures of vesicular–arbuscular mycorrhizal fungi

1985 ◽  
Vol 63 (7) ◽  
pp. 1329-1333 ◽  
Author(s):  
P. G. Williams
Keyword(s):  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Pasture Legumes ◽  
Affected Plant ◽  
Symbiotic Germination ◽  
Terrestrial Orchids ◽  
Vesicular Arbuscular ◽  
Orchid Seed ◽  
Sebacina Vermifera ◽  
Pot Culture

The paper reports that previously undescribed, sterile, septate fungi (Rhizoctonia) with affinity to and attributes of orchid mycorrhizal fungi, commonly occur in pot cultures of vesicular–arbuscular (V–A) mycorrhizal fungi. Seventeen pot cultures of V–A endophytes from several sources were studied. The endophytes included unidentified organisms as well as species of Glomus, Acaulospora, and Gigaspora. A Rhizoctonia was present in every pot culture. In different cases, Rhizoctonia isolates were obtained from sporelike cells in intramatrical vesicles, extramatrical hyphae, and chlamydospores or roots of pot culture plants. In pure culture, the rhizoctonias formed pale or yellow–brown, submerged colonies composed of narrow, irregularly septate hyphae. Monilioid hyphae and terminal or intercalary, spherical chlamydospores about 12 μm in diameter developed in older mycelia. Fruiting experiments by J. H. Warcup indicated that the teleomorph of three Rhizoctonia isolates is related to Sebacina vermifera Oberwinkler, a mycorrhizal endophyte of certain Australian terrestrial orchids. Positive tests for symbiotic germination of orchid seed with one isolate are described. Pasture legumes and ryegrass plants were inoculated with mycelia of Rhizoctonia strains in the presence or absence of V–A mycorrhizal fungi. Inoculation affected plant growth only when V–A mycorrhizal fungi were present: in steamed soil containing residual inoculum of a V–A endophyte, the growth response following infection by the V–A endophyte occurred in inoculated plants several weeks earlier than in uninoculated plants; in different natural soils, inoculation increased, decreased, or had no effect on growth, depending on the strain of Rhizoctonia used.

Seasonal dynamics of dominant species of arbuscular mycorrhizae in burned and unburned sand prairies

1993 ◽  
Vol 71 (12) ◽  
pp. 1625-1630 ◽  
Author(s):  
Shivcharn S. Dhillion ◽  
Roger C. Anderson
Keyword(s):  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizae ◽  
Root Zone ◽  
Arbuscular Mycorrhizal ◽  
Sampling Period ◽  
Growing Season ◽  
Individual Species ◽  
Seasonal Patterns ◽  
Growing Seasons ◽  
Spore Abundance

Seasonal variation in abundance of spores of arbuscular mycorrhizal fungi was examined for four growing seasons on burned and unburned sand prairies in Illinois. The three leading mycorrhizal species were an undescribed species of Glomus, Scutettospora heterogama, and Sclerocystis rubiformis, in order of decreasing abundance. Mycorrhizal spore abundance for all species generally showed similar seasonal patterns on burned and unburned sites during the sampling period, i.e., minimal in the middle of the growing season and maximal near the end of the season. Individual species, however, exhibited different seasonal patterns of sporulation or sporulation strategies. Burning caused a 2-year depression in spore abundance for Glomus species and Scutellospora heterogama, and a 3-year long depression in spore abundance for Sclerocystis rubiformis. The seasonal patterns observed were more discernible in root zone than in randomly collected soil. Spore abundances were always significantly lower on burned sites than on unburned sites early in the growing season. The results of this study, and studies conducted parallel to this one, suggest that the greater decline in spore abundance in burned sites than in unburned sites early in the growing season may be indirectly due to greater root growth, and (or) related changes in host physiology, in response to fire. Key words: mycorrhizae, fire, sand prairie, grassland, sporulation, inoculum, fungi.

scholarly journals In Vitro Symbiotic Germination: A Revitalized Heuristic Approach for Orchid Species Conservation

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1742
Author(s):  
Galih Chersy Pujasatria ◽  
Chihiro Miura ◽  
Hironori Kaminaka
Keyword(s):  
Natural Habitat ◽  
Species Conservation ◽  
In Vitro Study ◽  
Species Interaction ◽  
Life Cycles ◽  
Mycorrhizal Symbiosis ◽  
Promising Alternative ◽  
Symbiotic Germination

As one of the largest families of flowering plants, Orchidaceae is well-known for its high diversity and complex life cycles. Interestingly, such exquisite plants originate from minute seeds, going through challenges to germinate and establish in nature. Alternatively, orchid utilization as an economically important plant gradually decreases its natural population, therefore, driving the need for conservation. As with any conservation attempts, broad knowledge is required, including the species’ interaction with other organisms. All orchids establish mycorrhizal symbiosis with certain lineages of fungi to germinate naturally. Since the whole in situ study is considerably complex, in vitro symbiotic germination study is a promising alternative. It serves as a tool for extensive studies at morphophysiological and molecular levels. In addition, it provides insights before reintroduction into its natural habitat. Here we reviewed how mycorrhiza contributes to orchid lifecycles, methods to conduct in vitro study, and how it can be utilized for conservation needs.

scholarly journals Tulasnella calospora (UAMH 9824) retains its effectiveness at facilitating orchid symbiotic germination in vitro after two decades of subculturing

2021 ◽  
Vol 62 (1) ◽  
Author(s):  
Lawrence W. Zettler ◽  
Caleb J. Dvorak
Keyword(s):  
Mycorrhizal Fungi ◽  
Terrestrial Orchid ◽  
Orchid Species ◽  
The North ◽  
Symbiotic Germination ◽  
Germinating Seeds ◽  
Tulasnella Calospora

Abstract Background The technique of symbiotic germination—using mycorrhizal fungi to propagate orchids from seed in vitro—has been used as one method to cultivate orchids in North America and abroad for > 30 years. A long-held assumption is that mycorrhizal fungi used for this purpose lose their effectiveness at germinating seeds over time with repeated subculturing. Results We provide evidence for the lingering efficacy of one particular strain of Tulasnella calospora (266; UAMH 9824) to stimulate seed germination exemplified by the North American terrestrial orchid, Spiranthes cernua, as a case study. This fungus was originally acquired from roots from Spiranthes brevilabris in 1999 and sub-cultured during the two decades since. Seeds inoculated with the fungus in vitro developed to an advanced protocorm stage after 16 days, and leaf elongation was pronounced after 42 days. In a pilot study, seedlings co-cultured with Tulasnella calospora 266 were deflasked after 331 days and later transferred to soil under greenhouse conditions where they eventually initiated anthesis. During the course of two decades, seeds of 39 orchid species, cultivars and hybrids spanning 21 genera, germinated in vitro co-cultured with Tulasnella calospora 266. These orchids included temperate terrestrials and tropical epiphytes alike. Conclusions The sustained effectiveness of this fungus is noteworthy because it argues against the concept of mycorrhizal fungi losing their symbiotic capability through prolonged subculturing. This study serves as an example of why in situ habitat preservation is essential for the conservation of orchids as a source of potentially useful mycorrhizal fungi.

scholarly journals Finding a mycorrhizal fungus for reintroductions of the threatened terrestrial orchid Diuris fragrantissima

Lankesteriana ◽  
2015 ◽  
Vol 7 (1-2) ◽  
Author(s):  
Zoe Smith ◽  
Elizabeth James ◽  
Cassandra McLean
Keyword(s):  
Mycorrhizal Fungi ◽  
Mycorrhizal Fungus ◽  
Single Site ◽  
Critically Endangered ◽  
Terrestrial Orchid ◽  
Important Prerequisite ◽  
Terrestrial Orchids

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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