Nitrogen-phosphorus relationships in lichens
Nitrogen enrichment promotes phosphomonoesterase (PME) activity in the common heathland lichen Cladonia portentosa. This is associated with a marked increase in thallus N:P mass ratio and significant up-regulation of inorganic phosphate uptake capacity, evidencing a shift from N-limited to P-limite...
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| Format: | Thesis (University of Nottingham only) |
| Language: | English |
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2009
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| Online Access: | https://eprints.nottingham.ac.uk/10906/ |
| _version_ | 1848791151080898560 |
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| author | Hogan, Erika |
| author_facet | Hogan, Erika |
| author_sort | Hogan, Erika |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | Nitrogen enrichment promotes phosphomonoesterase (PME) activity in the common heathland lichen Cladonia portentosa. This is associated with a marked increase in thallus N:P mass ratio and significant up-regulation of inorganic phosphate uptake capacity, evidencing a shift from N-limited to P-limited growth. Phosphomonoesterase activity in C. portentosa responds rapidly to change in N deposition load, with a significant increase in activity recorded within 6 months of transplantation from a low-N to high-N site. The location of PME activity in C. portentosa was revealed using a fluorescent marker and was found to be concentrated on both the outer and inner surfaces of the hollow ‘tube-like’ thallus branches. Activity appeared to be associated exclusively with the mycobiont and was located within the hyphal-lumina, consistent with a membrane bound ecto-enzyme. High PME activity in axenic mycobiont cultures of C. portentosa provided further evidence of a fungal location and confirmed that rates of activity in this lichen are amongst the highest reported for any other plant/fungal system in the literature. Different classes of phosphatases were assayed in a range of N2-fixing and non-N2-fixing lichens in an oligotrophic subarctic environment. No relationship was found between the capacities for nitrogenase and PME activities. Maximum rates of PME activity were recorded in fruticose mat-forming lichens which capture nutrients predominantly from atmospheric deposits. 5´ nucleotide phosphodiesterase activity was readily detected in N2-fixing lichens and was particularly high in rhizine-rich regions of foliose terricolous lichen thalli, consistent with the utilisation of organic phosphates from soil and litter sources. |
| first_indexed | 2025-11-14T18:23:57Z |
| format | Thesis (University of Nottingham only) |
| id | nottingham-10906 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T18:23:57Z |
| publishDate | 2009 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-109062025-02-28T11:10:12Z https://eprints.nottingham.ac.uk/10906/ Nitrogen-phosphorus relationships in lichens Hogan, Erika Nitrogen enrichment promotes phosphomonoesterase (PME) activity in the common heathland lichen Cladonia portentosa. This is associated with a marked increase in thallus N:P mass ratio and significant up-regulation of inorganic phosphate uptake capacity, evidencing a shift from N-limited to P-limited growth. Phosphomonoesterase activity in C. portentosa responds rapidly to change in N deposition load, with a significant increase in activity recorded within 6 months of transplantation from a low-N to high-N site. The location of PME activity in C. portentosa was revealed using a fluorescent marker and was found to be concentrated on both the outer and inner surfaces of the hollow ‘tube-like’ thallus branches. Activity appeared to be associated exclusively with the mycobiont and was located within the hyphal-lumina, consistent with a membrane bound ecto-enzyme. High PME activity in axenic mycobiont cultures of C. portentosa provided further evidence of a fungal location and confirmed that rates of activity in this lichen are amongst the highest reported for any other plant/fungal system in the literature. Different classes of phosphatases were assayed in a range of N2-fixing and non-N2-fixing lichens in an oligotrophic subarctic environment. No relationship was found between the capacities for nitrogenase and PME activities. Maximum rates of PME activity were recorded in fruticose mat-forming lichens which capture nutrients predominantly from atmospheric deposits. 5´ nucleotide phosphodiesterase activity was readily detected in N2-fixing lichens and was particularly high in rhizine-rich regions of foliose terricolous lichen thalli, consistent with the utilisation of organic phosphates from soil and litter sources. 2009-12-10 Thesis (University of Nottingham only) NonPeerReviewed application/pdf en arr https://eprints.nottingham.ac.uk/10906/1/Erika_Hogan_Thesis_250809.pdf Hogan, Erika (2009) Nitrogen-phosphorus relationships in lichens. PhD thesis, University of Nottingham. Nitrogen enrichment Phosphomonoesterase activity Nutrient acquisition in lichens Phosphatase activity Phosphorus in lichens |
| spellingShingle | Nitrogen enrichment Phosphomonoesterase activity Nutrient acquisition in lichens Phosphatase activity Phosphorus in lichens Hogan, Erika Nitrogen-phosphorus relationships in lichens |
| title | Nitrogen-phosphorus relationships in lichens |
| title_full | Nitrogen-phosphorus relationships in lichens |
| title_fullStr | Nitrogen-phosphorus relationships in lichens |
| title_full_unstemmed | Nitrogen-phosphorus relationships in lichens |
| title_short | Nitrogen-phosphorus relationships in lichens |
| title_sort | nitrogen-phosphorus relationships in lichens |
| topic | Nitrogen enrichment Phosphomonoesterase activity Nutrient acquisition in lichens Phosphatase activity Phosphorus in lichens |
| url | https://eprints.nottingham.ac.uk/10906/ |