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The effect of forest nutrients status on ectomycorrhizal growth and community structure in response to minerals

Berner, Christoffer LU (2013)
Abstract (Swedish)
Popular Abstract in Swedish

Mycorrhiza är en samexistens mellan trädrötter och svampar i jorden. Svampen förser trädet med mineralnäringsämnen från jorden och i utbyte får den socker från trädet. Sockret produceras via fotosyntesen och transporteras sedan ner till rötterna där de förs vidare till svamphyferna.



Det har visats att mycorrhizasvampar kan ta upp näringsämnen direkt från mineraler i jorden. I mitt arbete utforskade jag hur svampar och träd reagerar på mineraler i jorden. Resultaten från mina försök visar att träd som lider av vissa näringsbrister, så som fosfor, kan transportera mer socker till rötterna och till sin symbiotiska svamp som då kan förlänga sina hyfer ut i jorden på jakt efter... (More)
Popular Abstract in Swedish

Mycorrhiza är en samexistens mellan trädrötter och svampar i jorden. Svampen förser trädet med mineralnäringsämnen från jorden och i utbyte får den socker från trädet. Sockret produceras via fotosyntesen och transporteras sedan ner till rötterna där de förs vidare till svamphyferna.



Det har visats att mycorrhizasvampar kan ta upp näringsämnen direkt från mineraler i jorden. I mitt arbete utforskade jag hur svampar och träd reagerar på mineraler i jorden. Resultaten från mina försök visar att träd som lider av vissa näringsbrister, så som fosfor, kan transportera mer socker till rötterna och till sin symbiotiska svamp som då kan förlänga sina hyfer ut i jorden på jakt efter näringsämnen i jorden. Svamptillväxten ökade i skogar som led av fosforbrist, men minskad då skogarna led av magnesiumbrist. Vidare ökade svamptillväxten i påsar som innehöll apatit (fosfor mineral) när trädet led av fosforbrist. Samma ökande svamptillväxt sågs dock inte i påsar som innehöll hornblände (magnesium mineral) då trädet led av magnesium brist eller i påsar med biotit (kalium mineral) då trädet led av kaliumbrist.



Detta kan betyda att trädet och svamparna kan kompensera för trädets fosforbrist genom att ta upp fosfor från mineralkällor medan denna funktion inte existerar när trädet lider av magnesium och kalium brist



Den minskade tillväxten vid magnesiumbrist kan bero på att sockertransporten till rötterna är blockerad. Magnesium tillsattes till en jord med magnesiumbrist vilket ökade sockerflödet till rötterna och till den symbiotiska svampen. Detta visar att gödsling med magnesium i magnesium fattiga skogar kan vara till fördel för näringsupptaget av trädet genom att den symbiotiska svampen kan sprida sig i jorden på jakt efter mineralnäringsämnen.

Svampsamhället har stor mångfald, upp emot 5000 arter har beskrivits och en trädsort kan vara i kontakt med upp till 100 olika svamparter.



Ett antal miljöfaktorer kan påverka svampsamhället. Olika bergrunder, som ger upphov till olika kemiska förhållande i jorden såsom olika pH, olika mängder näringsämnen, har olika svampsamhällen. Däremot ledde inte den ökade svamptillväxten i mineralpåsarna till någon förändring i svampsamhället i påsarna.



Sammanfattningsvis kan man säga att mycorrhizasvampar kan ta upp fosfor från mineraler vid fosforbrist, vilket inte är fallet vid magnesium- eller kaliumbrist. Däremot verkar det inte som om de svampar som gör detta blir belönade med mer socker från trädet. (Less)
Abstract
Ectomycorrhiza are a symbiosis between trees and soil inhabiting fungi. The fungal hyphae ensheath the fine roots creating a mantle and grow in between root cells to create the Hartig net, where the exchange of carbon and mineral nutrients occurs. The ectomycorrhizal fungus is dependent on the host tree to receive the carbon it needs to grow.



Trees with different nutrient deficiencies differ in the amounts of carbon they allocate to the roots and subsequently to the ectomycorrhizal fungi (EMF). It has been suggested that EMF are able to take up nutrients from mineral sources through the process of weathering. Presence of minerals rich in nutrients that the trees are deficient in might affect the growth of the EMF and the... (More)
Ectomycorrhiza are a symbiosis between trees and soil inhabiting fungi. The fungal hyphae ensheath the fine roots creating a mantle and grow in between root cells to create the Hartig net, where the exchange of carbon and mineral nutrients occurs. The ectomycorrhizal fungus is dependent on the host tree to receive the carbon it needs to grow.



Trees with different nutrient deficiencies differ in the amounts of carbon they allocate to the roots and subsequently to the ectomycorrhizal fungi (EMF). It has been suggested that EMF are able to take up nutrients from mineral sources through the process of weathering. Presence of minerals rich in nutrients that the trees are deficient in might affect the growth of the EMF and the EMF community structure.



In this thesis I used in-growth mesh bags amended with minerals to analyse how these minerals affected the growth of EMF as well and the community structure of the fungi, which grew into the mesh bags. The main results of the thesis are:



- Forests limited in phosphorus (P) have elevated EMF growth due to increased carbon allocation belowground. Magnesium and potassium limitations lead to decreased EMF growth, probably due to impaired belowground carbon allocation arising from these deficiencies.



- Colonisation of apatite (P mineral) by EMF increases during P limitation. Similar increased EMF colonisation was not seen when hornblende (Mg mineral) or biotite (K mineral) was present in Mg and K limited forests. This suggests that EMF growing in the field take up P by weathering of apatit in a similar way as has been found in controlled laboratory experiments. This is, however, not the case for K uptake from biotite or Mg uptake from hornblende during Mg and K limitations.



- Increased colonisation of apatite minerals did not translate to changes in EMF community composition in the mesh bags, suggesting that if some of the EMF species in the mesh bags are enhancing the weathering of minerals they are not rewarded with more carbon from the host tree.



- The impaired carbon allocation during Mg and K deficiency can be reversed by addition of these nutrients to the deficient soil. This also results in increased EMF growth, which enhances the nutrient uptake capacity of the trees. In this way, Mg addition should be considered as a remedy for forests suffering from low Mg status due to acid rain or due to intensive harvesting of forest residues. (Less)
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author
supervisor
opponent
  • Pennanen, Taina, The Finnish Forest Research Institute, Vantaa, Finland
organization
publishing date
type
Thesis
publication status
published
subject
pages
88 pages
publisher
Department of Biology, Lund University
defense location
Ecology building, Sölvegatan 37, 223 62 Lund
defense date
2013-03-01 10:00
ISBN
978-91-7473-447-8
project
BECC
language
English
LU publication?
yes
id
ffbb70c7-bb09-4404-9d15-1c9be991681b (old id 3457126)
date added to LUP
2013-02-06 21:18:28
date last changed
2016-09-19 08:45:10
@phdthesis{ffbb70c7-bb09-4404-9d15-1c9be991681b,
  abstract     = {Ectomycorrhiza are a symbiosis between trees and soil inhabiting fungi. The fungal hyphae ensheath the fine roots creating a mantle and grow in between root cells to create the Hartig net, where the exchange of carbon and mineral nutrients occurs. The ectomycorrhizal fungus is dependent on the host tree to receive the carbon it needs to grow.<br/><br>
<br/><br>
Trees with different nutrient deficiencies differ in the amounts of carbon they allocate to the roots and subsequently to the ectomycorrhizal fungi (EMF). It has been suggested that EMF are able to take up nutrients from mineral sources through the process of weathering. Presence of minerals rich in nutrients that the trees are deficient in might affect the growth of the EMF and the EMF community structure.<br/><br>
<br/><br>
In this thesis I used in-growth mesh bags amended with minerals to analyse how these minerals affected the growth of EMF as well and the community structure of the fungi, which grew into the mesh bags. The main results of the thesis are:<br/><br>
<br/><br>
- Forests limited in phosphorus (P) have elevated EMF growth due to increased carbon allocation belowground. Magnesium and potassium limitations lead to decreased EMF growth, probably due to impaired belowground carbon allocation arising from these deficiencies.<br/><br>
<br/><br>
- Colonisation of apatite (P mineral) by EMF increases during P limitation. Similar increased EMF colonisation was not seen when hornblende (Mg mineral) or biotite (K mineral) was present in Mg and K limited forests. This suggests that EMF growing in the field take up P by weathering of apatit in a similar way as has been found in controlled laboratory experiments. This is, however, not the case for K uptake from biotite or Mg uptake from hornblende during Mg and K limitations.<br/><br>
<br/><br>
- Increased colonisation of apatite minerals did not translate to changes in EMF community composition in the mesh bags, suggesting that if some of the EMF species in the mesh bags are enhancing the weathering of minerals they are not rewarded with more carbon from the host tree.<br/><br>
<br/><br>
- The impaired carbon allocation during Mg and K deficiency can be reversed by addition of these nutrients to the deficient soil. This also results in increased EMF growth, which enhances the nutrient uptake capacity of the trees. In this way, Mg addition should be considered as a remedy for forests suffering from low Mg status due to acid rain or due to intensive harvesting of forest residues.},
  author       = {Berner, Christoffer},
  isbn         = {978-91-7473-447-8},
  language     = {eng},
  pages        = {88},
  publisher    = {Department of Biology, Lund University},
  school       = {Lund University},
  title        = {The effect of forest nutrients status on ectomycorrhizal growth and community structure in response to minerals},
  year         = {2013},
}