Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Recruitment ecology and fungal interactions in mycoheterotrophic Ericaceae
Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

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.
Keyword [en]
454 Pyrosequencing, Dispersal limitation, Dust seeds, Ectomycorrhiza, Ericaceae, Microsite limitation, Monotropa hypopitys, Mycoheterotroph, Pyroleae, Seed limitation, Stable isotopes, Subterranean seedling, Symbiotic germination, Tricholoma
National Category
Ecology
Research subject
Plant Ecology
Identifiers
URN: urn:nbn:se:su:diva-109160ISBN: 978-91-7649-061-7 (print)OAI: oai:DiVA.org:su-109160DiVA: diva2:767181
Public defence
2015-01-30, föreläsningssalen, Institutionen för ekologi, miljö och botanik, Lilla Frescativägen 5, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

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.

Available from: 2015-01-08 Created: 2014-11-14 Last updated: 2015-01-07Bibliographically approved
List of papers
1. Recruitment limitation, germination of dust seeds, and early development of underground seedlings in six Pyroleae species
Open this publication in new window or tab >>Recruitment limitation, germination of dust seeds, and early development of underground seedlings in six Pyroleae species
2013 (English)In: Botany, ISSN 1916-2790, E-ISSN 1916-2804, Vol. 91, no 1, 17-24 p.Article in journal (Refereed) Published
Abstract [en]

We investigated recruitment of six mixotrophic Pyroleae species in relation to soil and adult presence. Pyroleae have dust seeds containing minimal nutrient reserves, and subterranean seedlings are mycoheterotrophic needing fungal hosts for germination and development. Germination and seedling development were studied by retrieving seed bags that had been placed within plots with adults present and at unoccupied control plots. There are two main alternatives to what limits recruitment of plants, seed limitation or microsite limitation. Results suggested that a combination of microsite and seed limitation was important for all investigated species. Microsite availability was the main limiting factor for Chimaphila umbellata (L.) W. P. C. Barton, Orthilia secunda (L.) House, and Pyrola chlorantha Sw., whereas seed availability was the main limiting factor for Pyrola minor L. For Moneses uniflora L. A. Gray and Pyrola rotundifolia L., it was not clear whether microsite or seed limitation dominated. Growth of seedlings responded positively to adult presence (O. secunda and P. minor), whereas others were negatively affected (M. uniflora and P. chlorantha). Increased levels of soil nutrients (N and P) had a negative effect on seedling growth in C. umbellata and P. chlorantha. These results provide the first evidence of the importance of microsite and seed limitation for germination and development of seedlings of Pyroleae species.

Keyword
dust seeds, microsite limitation, mixotrophy, pyroloids, seed limitation, symbiotic germination
National Category
Natural Sciences
Identifiers
urn:nbn:se:su:diva-88243 (URN)10.1139/cjb-2012-0153 (DOI)000314837500003 ()
Funder
Swedish Research Council
Note

AuthorCount:2;

Available from: 2013-03-15 Created: 2013-03-12 Last updated: 2017-12-06Bibliographically approved
2. Dust seed production and dispersal in Swedish Pyroleae species
Open this publication in new window or tab >>Dust seed production and dispersal in Swedish Pyroleae species
2014 (English)In: Nordic Journal of Botany, ISSN 0107-055X, E-ISSN 1756-1051, Vol. 32, no 2, 209-214 p.Article in journal (Refereed) Published
Abstract [en]

Dust seeds are the smallest seeds in angiosperms weighing just about a few micrograms. These seeds are characteristic of most orchids, and several studies have been performed on seed features, fecundity and dispersal of orchid dust seeds. In this study we examine seed features, seed production and seed dispersal in another plant group with dust seeds, the Pyroleae (Monotropoideae, Ericaceae), focusing on six species: Pyrola chlorantha, P. minor, P. rotundifolia, Chimaphila umbellata, Moneses uniflora and Orthilia secunda. Seed production per capsule among these species was in the range between ca 1000 and 7800, and seed production per capsule bearing shoot was in the range between ca 7000 and 60 000. Combining our results with published information on pollen-ovule ratios suggests that these Pyroleae species have a generally efficient pollination system. The most fecund species was P. minor, the only species among the investigated that is probably largely self-pollinating. The investigated Pyroleae species have a seed production comparable to the less fecund orchid species. We studied seed dispersal in the field in one of the species, P. chlorantha. Despite the extremely small and potentially buoyant seeds, the vast majority of seeds are deposited close to the seed source, within a few meters. Further studies on the recruitment ecology of the investigated Pyroleae species are currently under way.

National Category
Botany
Identifiers
urn:nbn:se:su:diva-103971 (URN)10.1111/j.1756-1051.2013.00307.x (DOI)000334799300015 ()
Funder
Swedish Research Council
Note

AuthorCount:3;

Available from: 2014-06-05 Created: 2014-05-27 Last updated: 2017-12-05Bibliographically approved
3. Partial mycoheterotrophy in Pyroleae: nitrogen and carbon stable isotope signatures during development from seedling to adult
Open this publication in new window or tab >>Partial mycoheterotrophy in Pyroleae: nitrogen and carbon stable isotope signatures during development from seedling to adult
2015 (English)In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 177, no 1, 203-211 p.Article in journal (Refereed) Published
Abstract [en]

Mycoheterotrophic plants (MHP) are divided into non-photosynthesizing full MHP and green-leaved partial or initial MHP. We investigated 13C and 15N isotope enrichment in five putatively partial MHP species in the tribe Pyroleae (Ericaceae): Chimaphila umbellata, Moneses uniflora, Orthilia secunda, Pyrola chlorantha and Pyrola minor, sampled from forest sites on Öland, Sweden. For M. uniflora and P. chlorantha, we investigated isotope signatures of subterranean seedlings (which are mycoheterotrophic), to examine how the use of seedlings instead of full MHP species (Hypopitys monotropa) as reference species affects the assessment of partial mycoheterotrophy. Our main findings were as follows: (1) All investigated Pyroleae species were enriched in 15N compared to autotrophic reference plants. (2) significant fungal-derived C among the Pyroleae species was found for O. secunda and P. chlorantha. For the remaining species of C. umbellata, M. uniflora and P. minor, isotope signatures suggested adult autotrophy. (3) C and N gains, calculated using seedlings as a full MHP reference, yielded qualitatively similar results as when using H. monotropa as a reference. However, the estimated differences in C and N gains became larger when using seedlings as an MHP reference. (4) A previously unknown interspecific variation in isotope signature occurs during early ontogeny, from seed production to developing seedlings. Our findings suggest that there is a variation among Pyroleae species concerning partial mycoheterotrophy in adults. Adult autotrophy may be most common in Pyroleae species, and these species may not be as dependent on fungal-derived nutrients as some green orchids.

Keyword
Dust seeds, Ericaceae, Mycoheterotrophy, Stable isotopes, Subterranean seedlings
National Category
Ecology
Research subject
Plant Ecology
Identifiers
urn:nbn:se:su:diva-109724 (URN)10.1007/s00442-014-3137-x (DOI)000347406500019 ()
Available from: 2014-11-28 Created: 2014-11-28 Last updated: 2017-12-05Bibliographically approved
4. Diversity of ectomycorrhizal fungi associated with Pyroleae and  Monotropa hypopitys during germination and seedling development
Open this publication in new window or tab >>Diversity of ectomycorrhizal fungi associated with Pyroleae and  Monotropa hypopitys during germination and seedling development
Show others...
(English)Manuscript (preprint) (Other academic)
Keyword
454 Pyrosequencing, Dust seeds, Ectomycorrhizal fungi, Monotropoideae, Mycoheterotrophy, Nonmetric multidimensional scaling (NMDS), Pyroleae, Symbiotic germination.
National Category
Ecology Botany
Research subject
Ecological Botany
Identifiers
urn:nbn:se:su:diva-109769 (URN)
Available from: 2014-12-01 Created: 2014-12-01 Last updated: 2014-12-01

Open Access in DiVA

Veronika Johansson Dissertation(1159 kB)302 downloads
File information
File name FULLTEXT01.pdfFile size 1159 kBChecksum SHA-512
8e0881847978d45fc36339a681046fb25aa2ca6e9ed222952b1cdd69b4057d540f13069eec92a7e725c133a50e76734307cfcf74b3aa5e6845cc609f488c8838
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Johansson, Veronika A.
By organisation
Department of Ecology, Environment and Plant Sciences
Ecology

Search outside of DiVA

GoogleGoogle Scholar
Total: 302 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 638 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf