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Melanisation in Boreal Lichens Is Accompanied by Variable Changes in Non-Photochemical Quenching

Lichens often grow in microhabitats where they absorb more light than they can use for fixing carbon, and this excess energy can cause the formation of harmful reactive oxygen species (ROS). Lichen mycobionts can reduce ROS formation by synthesizing light-screening pigments such as melanins in the u...

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Autores principales: Ndhlovu, Nqobile Truelove, Solhaug, Knut Asbjørn, Minibayeva, Farida, Beckett, Richard Peter
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9607152/
https://www.ncbi.nlm.nih.gov/pubmed/36297748
http://dx.doi.org/10.3390/plants11202726
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author Ndhlovu, Nqobile Truelove
Solhaug, Knut Asbjørn
Minibayeva, Farida
Beckett, Richard Peter
author_facet Ndhlovu, Nqobile Truelove
Solhaug, Knut Asbjørn
Minibayeva, Farida
Beckett, Richard Peter
author_sort Ndhlovu, Nqobile Truelove
collection PubMed
description Lichens often grow in microhabitats where they absorb more light than they can use for fixing carbon, and this excess energy can cause the formation of harmful reactive oxygen species (ROS). Lichen mycobionts can reduce ROS formation by synthesizing light-screening pigments such as melanins in the upper cortex, while the photobionts can dissipate excess energy radiationlessly using non-photochemical quenching (NPQ). An inherent problem with using fluorimetry techniques to compare NPQ in pale and melanised thalli is that NPQ is normally measured through a variously pigmented upper cortex. Here we used a dissection technique to remove the lower cortices and medullas of Lobaria pulmonaria and Crocodia aurata and then measure NPQ from the underside of the thallus. Results confirmed that NPQ can be satisfactorily assessed with a standard fluorimeter by taking measurement from above using intact thalli. However, photobionts from the bottom of the photobiont layer tend to have slightly lower rates of PSII activity and lower NPQ than those at the top, i.e., display mild “shade” characteristics. Analysis of pale and melanised thalli of other species indicates that NPQ in melanised thalli can be higher, similar or lower than pale thalli, probably depending on the light history of the microhabitat and presence of other tolerance mechanisms.
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spelling pubmed-96071522022-10-28 Melanisation in Boreal Lichens Is Accompanied by Variable Changes in Non-Photochemical Quenching Ndhlovu, Nqobile Truelove Solhaug, Knut Asbjørn Minibayeva, Farida Beckett, Richard Peter Plants (Basel) Article Lichens often grow in microhabitats where they absorb more light than they can use for fixing carbon, and this excess energy can cause the formation of harmful reactive oxygen species (ROS). Lichen mycobionts can reduce ROS formation by synthesizing light-screening pigments such as melanins in the upper cortex, while the photobionts can dissipate excess energy radiationlessly using non-photochemical quenching (NPQ). An inherent problem with using fluorimetry techniques to compare NPQ in pale and melanised thalli is that NPQ is normally measured through a variously pigmented upper cortex. Here we used a dissection technique to remove the lower cortices and medullas of Lobaria pulmonaria and Crocodia aurata and then measure NPQ from the underside of the thallus. Results confirmed that NPQ can be satisfactorily assessed with a standard fluorimeter by taking measurement from above using intact thalli. However, photobionts from the bottom of the photobiont layer tend to have slightly lower rates of PSII activity and lower NPQ than those at the top, i.e., display mild “shade” characteristics. Analysis of pale and melanised thalli of other species indicates that NPQ in melanised thalli can be higher, similar or lower than pale thalli, probably depending on the light history of the microhabitat and presence of other tolerance mechanisms. MDPI 2022-10-15 /pmc/articles/PMC9607152/ /pubmed/36297748 http://dx.doi.org/10.3390/plants11202726 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Ndhlovu, Nqobile Truelove
Solhaug, Knut Asbjørn
Minibayeva, Farida
Beckett, Richard Peter
Melanisation in Boreal Lichens Is Accompanied by Variable Changes in Non-Photochemical Quenching
title Melanisation in Boreal Lichens Is Accompanied by Variable Changes in Non-Photochemical Quenching
title_full Melanisation in Boreal Lichens Is Accompanied by Variable Changes in Non-Photochemical Quenching
title_fullStr Melanisation in Boreal Lichens Is Accompanied by Variable Changes in Non-Photochemical Quenching
title_full_unstemmed Melanisation in Boreal Lichens Is Accompanied by Variable Changes in Non-Photochemical Quenching
title_short Melanisation in Boreal Lichens Is Accompanied by Variable Changes in Non-Photochemical Quenching
title_sort melanisation in boreal lichens is accompanied by variable changes in non-photochemical quenching
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9607152/
https://www.ncbi.nlm.nih.gov/pubmed/36297748
http://dx.doi.org/10.3390/plants11202726
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