Symbiotic Seed Germination and Mycorrhizae of Federally Threatened Platanthera praeclara (Orchidaceae)

Sharma, Jyotsna; Zettler, Lawrence W.; Sambeek, J. W. Van; Ellersieck, Mark R.; Starbuck, Christopher J.

doi:10.1674/0003-0031(2003)149[0104:ssgamo]2.0.co;2

Cited by 68 publications

(49 citation statements)

References 9 publications

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“…Analyses of genetic structure among populations (Ross and Travers 2015) up to 200 km apart found relatively low levels of divergence (Gst = 0.08). Previous studies found similar results (Sharma 2002;Pleasants and Klier 1995). In the absence of evidence for ecotypic differentiation among even these distant populations, we predict that inbreeding depression is more important than outbreeding depression in this species.…”

Section: Pollinator Behavior and Self-pollinationsupporting

confidence: 77%

Breeding system and inbreeding depression in the rare orchid,Platanthera praeclara, in a fragmented grassland landscape

Travers

Anderson

Vitt

et al. 2018

Botany

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An important consequence of self-compatibility in plants is that self-pollination can have deleterious effects on plant fitness due to inbreeding. We conducted a hand pollination experiment under field conditions to measure the magnitude of inbreeding depression associated with self-pollination in the rare western prairie fringed-orchid Platanthera praeclara Sheviak and Bowles. By comparing capsules and seeds resulting from cross versus self-pollination treatments, we determined that self-pollination reduces seed quality while having no detectable effect on capsule production or seed numbers. A smaller percentage of seeds resulting from self-pollination contained an embryo (18%) relative to seeds from cross-pollination (46%). Seeds that had an embryo were scored for the size of the embryo, small or large. A smaller proportion of seeds from self-pollination contained a large embryo (75%) relative to seeds from cross-pollination (92%).These results suggest that sexual reproduction and recruitment in this rare plant are dependent on the frequency of pollinator visitations that result in outcrossing.

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Section: Pollinator Behavior and Self-pollinationsupporting

confidence: 77%

Breeding system and inbreeding depression in the rare orchid,Platanthera praeclara, in a fragmented grassland landscape

Travers

Anderson

Vitt

et al. 2018

Botany

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“…Ceratobasidiaceae occur in several Platanthera species, together with more frequent Tulasnellaceae species (occasionally under the anamorphic name 'Epulorhiza'; Currach et al, 1990;Zelmer & Currah, 1995;Zelmer et al, 1996;Sharma et al, 2003). Zettler (2005) induced seed germination and seedling growth to the green leaf stage in Platanthera leucophaea (Nutt.)…”

Section: P Minor Is Specifically Associated With Ceratobasidiaceaementioning

confidence: 99%

“…Most mycobionts of Platanthera species identified are members of the teleomorphic fungal families Ceratobasidiaceae and Tulasnellaceae (Currach et al, 1990;Zelmer & Currah, 1995;Zelmer et al, 1996;Sharma et al, 2003;Bidartondo et al, 2004), which belong to the anamorphic, polyphyletic form-genus Rhizoctonia. The association with Rhizoctonia-type fungi is a common feature of many photosynthetic orchids (Rasmussen, 2002;Dearnaley, 2007).…”

Section: Introductionmentioning

confidence: 99%

Mixotrophy of Platanthera minor, an orchid associated with ectomycorrhiza‐forming Ceratobasidiaceae fungi

et al. 2011

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C, d15 N. Summary• We investigated the fungal symbionts and carbon nutrition of a Japanese forest photosynthetic orchid, Platanthera minor, whose ecology suggests a mixotrophic syndrome, that is, a mycorrhizal association with ectomycorrhiza (ECM)-forming fungi and partial exploitation of fungal carbon.• We performed molecular identification of symbionts by PCR amplifications of the fungal ribosomal DNA on hyphal coils extracted from P. minor roots. We tested for a 13 C and 15 N enrichment characteristic of mixotrophic plants. We also tested the ectomycorrhizal abilities of orchid symbionts using a new protocol of direct inoculation of hyphal coils onto roots of Pinus densiflora seedlings.• In phylogenetic analyses, most isolated fungi were close to ECM-forming Ceratobasidiaceae clades previously detected from a few fully heterotrophic orchids or environmental ectomycorrhiza surveys. The direct inoculation of fungal coils of these fungi resulted in ectomycorrhiza formation on P. densiflora seedlings. Stable isotope analyses indicated mixotrophic nutrition of P. minor, with fungal carbon contributing from 50% to 65%.• This is the first evidence of photosynthetic orchids associated with ectomycorrhizal Ceratobasidiaceae taxa, confirming the evolution of mixotrophy in the Orchideae orchid tribe, and of ectomycorrhizal abilities in the Ceratobasidiaceae. Our new ectomycorrhiza formation technique may enhance the study of unculturable orchid mycorrhizal fungi.

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“…Intraspecific variation in the performance of plants with mycorrhizae has been shown in orchids (Sharma et al, 2003, Taylor et al, 2004, ectomycorrhizal plants (Dixon et al, 1987;Tonnkin et al, 1989;Thompson et al, 1990;Tagu et al, 2001), and arbuscular mycorrhizal plants ( Van der Heijden and Kuyper, 2001). We suspect that such variation may be quite common and perhaps the norm.…”

Section: Variation Among Plantsmentioning

confidence: 99%

Variation in mycorrhizal performance in the epiphytic orchid Tolumnia variegata in vitro: the potential for natural selection

2005

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Symbiotic seed germination is a critical stage in orchid life histories. Natural selection may act to favor plants that efficiently use mycorrhizal fungi. However, the necessary conditions for natural selection -variation, heritability, and differences in fitness -have not been demonstrated for either orchid or fungus. With the epiphytic orchid Tolumnia variegata as a model system, we ask the following questions: (1) Do seeds from different individuals in a population differ in germination and seedling development in the presence of the same fungi? (2) Do different mycorrhizal fungi (Ceratobasidium spp.) differ in ability to stimulate seed germination and growth in T. variegata? And (3) are the Ceratobasidium isolates that best induce seed germination and seedling development more closely related to each other than to isolates that are less effective? We performed symbiotic seed germination experiments in vitro. The experiments were done using mycorrhizal fungi isolated from T. variegata; relationships among the fungi were inferred from nuclear ribosomal ITS sequences. We found significant variation for both symbiotic germination and seedling growth among biparental seed crops obtained from a population of T. variegata plants. Differences among Ceratobasidium fungi in seed germination were significant. The fungi that induced highest seed germination and seedling development belonged to two of four clades of Ceratobasidium. The two experiments show that there is potential for natural selection to act on orchid-fungus relationships. Given that orchids vary in performance, and that mycorrhizal fungi are not geographically distributed homogeneously, mycorrhizae may affect population size, distribution and evolution of orchids.

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Symbiotic Seed Germination and Mycorrhizae of Federally Threatened Platanthera praeclara (Orchidaceae)

Cited by 68 publications

References 9 publications

Breeding system and inbreeding depression in the rare orchid,Platanthera praeclara, in a fragmented grassland landscape

Breeding system and inbreeding depression in the rare orchid,Platanthera praeclara, in a fragmented grassland landscape

Mixotrophy of Platanthera minor, an orchid associated with ectomycorrhiza‐forming Ceratobasidiaceae fungi

Variation in mycorrhizal performance in the epiphytic orchid Tolumnia variegata in vitro: the potential for natural selection

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