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Evidences on the Ability of Mycorrhizal Genus Piloderma to Use Organic Nitrogen and Deliver It to Scots Pine.

Heinonsalo J, Sun H, Santalahti M, Bäcklund K, Hari P, Pumpanen J - PLoS ONE (2015)

Bottom Line: We also tested the effect of Piloderma olivaceum on host plant organic N nutrition in the laboratory.The results showed that Piloderma sp. was highly abundant in the field and produced extracellular proteases, which correlated positively with the gross primary production, temperature and soil respiration.As Piloderma sp. abundance appeared to be seasonally highly variable, recycling of fungal-bound N after hyphal death may therefore be of primary importance for the N cycling in boreal ecosystems.

View Article: PubMed Central - PubMed

Affiliation: Department of Food and Environmental Sciences, University of Helsinki, Helsinki, Finland.

ABSTRACT
Ectomycorrhizal (ECM) symbiosis has been proposed to link plant photosynthesis and soil organic matter (SOM) decomposition through the production of fungal enzymes which promote SOM degradation and nitrogen (N) uptake. However, laboratory and field evidence for the existence of these processes are rare. Piloderma sp., a common ECM genus in boreal forest soil, was chosen as model mycorrhiza for this study. The abundance of Piloderma sp. was studied in root tips and soil over one growing season and in winter. Protease production was measured from ectomycorrhiza and soil solution in the field and pure fungal cultures. We also tested the effect of Piloderma olivaceum on host plant organic N nutrition in the laboratory. The results showed that Piloderma sp. was highly abundant in the field and produced extracellular proteases, which correlated positively with the gross primary production, temperature and soil respiration. In the laboratory, Piloderma olivaceum could improve the ability of Pinus sylvestris L. to utilize N from extragenous proteins. We suggest that ECM fungi, although potentially retaining N in their hyphae, are important in forest C and N cycling due to their ability to access proteinaeous N. As Piloderma sp. abundance appeared to be seasonally highly variable, recycling of fungal-bound N after hyphal death may therefore be of primary importance for the N cycling in boreal ecosystems.

No MeSH data available.


The average protease quantities in soil solution and in all ECM root tips over one growth season.The data was extrapolated to represent protease quantities (μg) per surface of soil (m2). No data was available for April. The Y-axis is in a logarithmic scale. Differences between protease quantities in soil solution and ECM root tips or between months were not significantly different due to large variation.
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pone.0131561.g003: The average protease quantities in soil solution and in all ECM root tips over one growth season.The data was extrapolated to represent protease quantities (μg) per surface of soil (m2). No data was available for April. The Y-axis is in a logarithmic scale. Differences between protease quantities in soil solution and ECM root tips or between months were not significantly different due to large variation.

Mentions: In soil solution, higher protease production per m2 forest soil was observed than that in all ECM root tips together: protease production averages in soil were 15–300 times higher than that in ECM tips (Fig 3) but the differences were not statistically significant due to large variation (independent-samples non-parametric Kruskal-Wallis test, P = 0.309). However, the production in ECM appeared more stable throughout the year. Protease production in soil was highest in March, under snow cover, whereas the peak of protease production in ECM root tips was in spring and autumn (Fig 3). Protease quantities did not differ significantly between months (independent-samples non-parametric Kruskal-Wallis test, P = 0.115 for soil solution, P = 0.370 for ECM). The number of protease-producing ECM root tips seemed to peak in early summer and in autumn whereas the number of protease-producing Piloderma sp. tips during the summer months (Fig 4). On average, 13% of all ECM root tips showed protease production and this proportion was relatively stable over the growing season.


Evidences on the Ability of Mycorrhizal Genus Piloderma to Use Organic Nitrogen and Deliver It to Scots Pine.

Heinonsalo J, Sun H, Santalahti M, Bäcklund K, Hari P, Pumpanen J - PLoS ONE (2015)

The average protease quantities in soil solution and in all ECM root tips over one growth season.The data was extrapolated to represent protease quantities (μg) per surface of soil (m2). No data was available for April. The Y-axis is in a logarithmic scale. Differences between protease quantities in soil solution and ECM root tips or between months were not significantly different due to large variation.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4489387&req=5

pone.0131561.g003: The average protease quantities in soil solution and in all ECM root tips over one growth season.The data was extrapolated to represent protease quantities (μg) per surface of soil (m2). No data was available for April. The Y-axis is in a logarithmic scale. Differences between protease quantities in soil solution and ECM root tips or between months were not significantly different due to large variation.
Mentions: In soil solution, higher protease production per m2 forest soil was observed than that in all ECM root tips together: protease production averages in soil were 15–300 times higher than that in ECM tips (Fig 3) but the differences were not statistically significant due to large variation (independent-samples non-parametric Kruskal-Wallis test, P = 0.309). However, the production in ECM appeared more stable throughout the year. Protease production in soil was highest in March, under snow cover, whereas the peak of protease production in ECM root tips was in spring and autumn (Fig 3). Protease quantities did not differ significantly between months (independent-samples non-parametric Kruskal-Wallis test, P = 0.115 for soil solution, P = 0.370 for ECM). The number of protease-producing ECM root tips seemed to peak in early summer and in autumn whereas the number of protease-producing Piloderma sp. tips during the summer months (Fig 4). On average, 13% of all ECM root tips showed protease production and this proportion was relatively stable over the growing season.

Bottom Line: We also tested the effect of Piloderma olivaceum on host plant organic N nutrition in the laboratory.The results showed that Piloderma sp. was highly abundant in the field and produced extracellular proteases, which correlated positively with the gross primary production, temperature and soil respiration.As Piloderma sp. abundance appeared to be seasonally highly variable, recycling of fungal-bound N after hyphal death may therefore be of primary importance for the N cycling in boreal ecosystems.

View Article: PubMed Central - PubMed

Affiliation: Department of Food and Environmental Sciences, University of Helsinki, Helsinki, Finland.

ABSTRACT
Ectomycorrhizal (ECM) symbiosis has been proposed to link plant photosynthesis and soil organic matter (SOM) decomposition through the production of fungal enzymes which promote SOM degradation and nitrogen (N) uptake. However, laboratory and field evidence for the existence of these processes are rare. Piloderma sp., a common ECM genus in boreal forest soil, was chosen as model mycorrhiza for this study. The abundance of Piloderma sp. was studied in root tips and soil over one growing season and in winter. Protease production was measured from ectomycorrhiza and soil solution in the field and pure fungal cultures. We also tested the effect of Piloderma olivaceum on host plant organic N nutrition in the laboratory. The results showed that Piloderma sp. was highly abundant in the field and produced extracellular proteases, which correlated positively with the gross primary production, temperature and soil respiration. In the laboratory, Piloderma olivaceum could improve the ability of Pinus sylvestris L. to utilize N from extragenous proteins. We suggest that ECM fungi, although potentially retaining N in their hyphae, are important in forest C and N cycling due to their ability to access proteinaeous N. As Piloderma sp. abundance appeared to be seasonally highly variable, recycling of fungal-bound N after hyphal death may therefore be of primary importance for the N cycling in boreal ecosystems.

No MeSH data available.