Recruitment ecology and fungal interactions in mycoheterotrophic Ericaceae
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
There are generally two contrasting alternatives to what limits recruitment in plants, namely the availability of seeds (seed limitation) or the quality or quantity of suitable sites (microsite limitation). Dust seeds, the smallest existing seeds, lack or have minimal nutrient reserves. During germination and initial development they consequently parasitize on mycorrhizal fungi. This is called mycoheterotrophy, and can vary in degree of fungal dependency in adult plants from full, partial or initial mycoheterotrophy.
The aim of this thesis was to investigate the recruitment ecology of mycoheterotrophic Ericaceae (tribe Pyroleae) species with dust seeds, and to determine what limits their recruitment. The investigated species were: Chimaphila umbellata, Moneses uniflora, Orthilia secunda, Pyrola chlorantha, P. minor and P. rotundifolia. This aim was achieved by combining field experiments (seed sowing) with isotope analysis and fungal host pyrosequencing.
Results provide evidence that the species in Pyroleae are heterogeneous, not only with regard to their degree of mycoheterotrophy, but also concerning germination and early seedling development. A combination of microsite and seed limitation is thus likely to be of importance for all studied species, but the relative importance of these limitations varies among species. Despite having adaptations for wind dispersal the majority of the seeds were deposited in close vicinity of the seed source. But with high seed production at least some seeds should be able to disperse long-distance. Seedlings of all studied species were found to associate with a wide range of ectomycorrhizal fungi, at least during their initial developmental stages. There seems to be a tendency for host narrowing in some Pyroleae species, but not as strict as the host specialization seen in fully mycoheterotrophic Monotropa hypopitys, supporting the hypothesis of geographical and developmental host shifts.
Place, publisher, year, edition, pages
Stockholm: Department of Ecology, Environment and Plant Sciences, Stockholm University , 2014. , 46 p.
454 Pyrosequencing, Dispersal limitation, Dust seeds, Ectomycorrhiza, Ericaceae, Microsite limitation, Monotropa hypopitys, Mycoheterotroph, Pyroleae, Seed limitation, Stable isotopes, Subterranean seedling, Symbiotic germination, Tricholoma
Research subject Plant Ecology
IdentifiersURN: urn:nbn:se:su:diva-109160ISBN: 978-91-7649-061-7OAI: oai:DiVA.org:su-109160DiVA: diva2:767181
2015-01-30, föreläsningssalen, Institutionen för ekologi, miljö och botanik, Lilla Frescativägen 5, Stockholm, 10:00 (English)
Taylor, Andrew, Professor
Eriksson, Ove, Professor
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: In press. Paper 4: Manuscript.2015-01-082014-11-142015-01-07Bibliographically approved
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