Symbiotic relationships of <i>alnus glutinosa</i> with arbuscular mycorrhizal fungi and with <i>frankia</i>

The occurrence in Scotland of arbuscular mycorrhizal fungi (AMF) infective on <i>Alnus glutinosa</i> and the effects on early growth of inoculation of seedlings with AMF and <i>Frankia </i>were investigated. AMF characteristic of <i>Glomus</i>-like fungi were detected microscopically in <i>A. glutinosa</i> roots from mineral and loam but not from highly organic soils. Both <i>Glomus</i>- and <i>Gigaspora</i>-like fungi were detected only in roots from sandy soils. Glasshouse experiments showed that <i>Glomus</i> and <i>Gigaspora</i> species gave higher colonisation of roots, and were of higher compatibility with the host plant, than <i>Acutelospora</i> or <i>Scutellospora </i>species.<br/><br/>Colonisation by AMF increased nodulation by <i>Frankia</i> and <i>vice versa</i>. Inoculation with AMF alone and dual inoculation with <i>Gigaspora rosea</i> and <i>Frankia</i> inhibited growth of young <i>A. glutinosa </i>seedlings. Initially after inoculation, AMF colonisation was poor allowing the host to meet the requirements of both developing symbioses. Mycorrhizal plants inoculated with <i>Frankia</i> 15 days after AMF inoculation, were under significant stress and this delayed the beneficial effects of AMF and <i>Frankia </i>symbiosis. Seedlings compensated for the cost of symbiosis by developing a larger, leafy shoot in a period of 25-30 days after AMF inoculation, with or with out, <i>Frankia</i> nodulation.<br/><br/>A significant increase in root length and branching detected after inoculation with AMF and <i>Frankia</i> must impose additional energy requirements. However, the stimulation of lateral root branching that follows AMF colonisation may facilitate nutrient uptake, thus helping the plant to overcome the disadvantages of early retardation of shoot growth. Competition with adjacent plant species for below ground space may also be enhanced thus facilitating competition for growing space with other plant species. These factors may be part of a strategy that assists the survival of very young seedlings in the field.<br/><br/>The data obtained suggest that delaying<i> Frankia</i> inoculation for 3-4 weeks after inoculation with selected AMF should improve the production in Scottish nurseries of robust, well nodulated and mycorrhizal seedlings.

Name dc:type.qualificationname

Doctoral Thesis

Level dc:type.qualificationlevel

Student thesis

Year dc:date.issued

2003

Author dc:creator

• Orfanoudakis , Michail

• f arbuscular mycorrhizal fungi
• Alnus glutinosa
• Common alder
• AMF
• fungi
• infection
• inoculation
• Scotland
• Frankia
• mycorrhizal seedlings

Language dc:language

eng

Identifier

oai:pure.atira.dk:studenttheses/c70364aa-677c-4611-a733-ffd98314a733

OAI identifier oai:identifier

oai:pure.atira.dk:studenttheses/c70364aa-677c-4611-a733-ffd98314a733