Nitrogen Metabolism in Lichens

Millbank, J. W.; Kershaw, K. A.

doi:10.1111/j.1469-8137.1969.tb06476.x

Cited by 52 publications

(25 citation statements)

References 14 publications

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“…Henriksson and Simu (1971), for example, in their investigation of the capacity of Collema and Peltigera to fix nitrogen in the laboratory after various periods of desiccation, expressed their results relative to the dry weight of the thallus rather than to the Nostoc phycobiont. When fixation was related to the amount of Nostoc present, Millbank and Kershaw (1969) reported the rates were strikingly rapid, and the present paper has amplified this finding. Stewart et al (1968) report mean rates of acetylene reduction of 3.7 nM/minute/mg protein, w ith a maximum of 4. i, in A^.…”

Section: Discussionsupporting

confidence: 74%

“…Bond and Scott, 1955;Scott, 1956;Henriksson and Simu, 1971;Millbank and Kershaw, 1969;Kershaw and Millbank, 1970), little quantitative data on the rates of fixation exhibited by the symbiont responsible for the process have been reported. Henriksson and Simu (1971), for example, in their investigation of the capacity of Collema and Peltigera to fix nitrogen in the laboratory after various periods of desiccation, expressed their results relative to the dry weight of the thallus rather than to the Nostoc phycobiont.…”

Section: Discussionmentioning

confidence: 99%

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NITROGEN METABOLISM IN LICHENS IV. THE NITROGENASE ACTIVITY OF THE NOSTOC PHYCOBIONT IN PELTIGERA CANINA

Millbank

1972

New Phytologist

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Summary The content of the blue‐green alga phycobiont, Nostoc sp. in the lichen Peltigera canina has been estimated using various techniques and represents on average 2.7% of the total thallus nitrogen. Expressed in terms of cell numbers, this represents approximately 3 × 106 cells cm2, mature thallus. The nitrogenase activity, expressed as nil ethylene evolved/minute/mg Sostoc protein, varies considerably with the thallus sample, but a mean value of 10, considerably greater than that in free‐living Nostoc, has been found. The nitrogenase activity of the algal cells is particularly sensitive to disturbance of the thallus structure and the implications of these findings are discussed.

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Section: Discussionsupporting

confidence: 74%

Section: Discussionmentioning

confidence: 99%

NITROGEN METABOLISM IN LICHENS IV. THE NITROGENASE ACTIVITY OF THE NOSTOC PHYCOBIONT IN PELTIGERA CANINA

Millbank

1972

New Phytologist

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“…5 K. Trebouxia sp. was isolated from R. yasudae according to Millbank and Kershaw (1969) with slight modifications (Kosugi et al 2009). …”

Section: Sample Preparationmentioning

confidence: 99%

Multiple dissipation components of excess light energy in dry lichen revealed by ultrafast fluorescence study at 5 K

et al. 2011

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A time-resolved fluorescence study of living lichen thalli at 5 K was conducted to clarify the dynamics and mechanism of the effective dissipation of excess light energy taking place in lichen under extreme drought conditions. The decay-associated spectra obtained from the experiment at 5 K were characterized by a drastically sharpened spectral band which could not be resolved by experiments at higher temperatures. The present results indicated the existence of two distinct dissipation components of excess light energy in desiccated lichen; one is characterized as rapid fluorescence decay with a time constant of 27 ps in the far-red region that was absent in wet lichen thalli, and the other is recognized as accelerated fluorescence decay in the 685-700 nm spectral region. The former energy-dissipation component with extremely high quenching efficiency is most probably ascribed to the emergence of a rapid quenching state in the peripheral-antenna system of photosystem II (PS II) on desiccation. This is an extremely effective protection mechanism of PS II under desiccation, which lichens have developed to survive in the severely desiccated environments. The latter, which is less efficient at 5 K, might have a supplementary role and take place either in the core antenna of PS II or aggregated peripheral antenna of PS II.

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“…8]. Although their importance as an N source in boreal and arctic ecosystems has been recognized for decades [9][10][11][12], no attempts have been made so far to assess the contribution of different N 2 fixer associations to the N cycle at ecosystem level.…”

Section: Introductionmentioning

confidence: 99%

Across-Habitat Comparison of Diazotroph Activity in the Subarctic

et al. 2014

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Nitrogen (N) fixation by N2-fixing bacteria (diazotrophs) is the primary N input to pristine ecosystems like boreal forests and subarctic and arctic tundra. However, the contribution by the various diazotrophs to habitat N2 fixation remains unclear. We present results from in situ assessments of N2 fixation of five diazotroph associations (with a legume, lichen, feather moss, Sphagnum moss and free-living) incorporating the ground cover of the associations in five typical habitats in the subarctic (wet and dry heath, polygon-heath, birch forest, mire). Further, we assessed the importance of soil and air temperature, as well as moisture conditions for N2 fixation. Across the growing season, the legume had the highest total as well as the highest fraction of N2 fixation rates at habitat level in the heaths (>85 % of habitat N2 fixation), whereas the free-living diazotrophs had the highest N2 fixation rates in the polygon heath (56 %), the lichen in the birch forest (87 %) and Sphagnum in the mire (100 %). The feather moss did not contribute more than 15 % to habitat N2 fixation in any of the habitats despite its high ground cover. Moisture content seemed to be a major driver of N2 fixation in the lichen, feather moss and free-living diazotrophs. Our results show that the range of N2 fixers found in pristine habitats contribute differently to habitat N2 fixation and that ground cover of the associates does not necessarily mirror contribution.

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Nitrogen Metabolism in Lichens

Cited by 52 publications

References 14 publications

NITROGEN METABOLISM IN LICHENS IV. THE NITROGENASE ACTIVITY OF THE NOSTOC PHYCOBIONT IN PELTIGERA CANINA

NITROGEN METABOLISM IN LICHENS IV. THE NITROGENASE ACTIVITY OF THE NOSTOC PHYCOBIONT IN PELTIGERA CANINA

Multiple dissipation components of excess light energy in dry lichen revealed by ultrafast fluorescence study at 5 K

Across-Habitat Comparison of Diazotroph Activity in the Subarctic

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