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

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 cha...

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Bibliographic Details
Published in:Photosynthesis research 2011-10, Vol.110 (1), p.39-48
Main Authors: Miyake, Hirohisa, Komura, Masayuki, Itoh, Shigeru, Kosugi, Makiko, Kashino, Yasuhiro, Satoh, Kazuhiko, Shibata, Yutaka
Format: Article
Language:English
Subjects:
Biochemistry
Biomedical and Life Sciences
Desiccation
Droughts
Energy dissipation
Energy Transfer - radiation effects
Fluorescence
Japan
Lichens
Lichens - metabolism
Lichens - radiation effects
Life Sciences
Light
Photosynthesis
Photosynthesis - radiation effects
Photosystem II Protein Complex - radiation effects
Plant Genetics and Genomics
Plant Physiology
Plant Sciences
Regular Paper
Spectrometry, Fluorescence - methods
Stress, Physiological
Temperature
Time Factors
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Summary: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.
ISSN:0166-8595
1573-5079
DOI:10.1007/s11120-011-9691-8