Species- and strain-specific strategies of microalgal strains (desmids, genus Cosmarium, Zygnematophyceae, Streptophyta) as protection against excessive photosynthetically active radiation
2017
Document Type:
Conference object (Published version)
,
© 2017 by The Society for Experimental Biology
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Show full item recordAbstract:
We examined the influence of irradiance on protection strategies
of four microalgal strain belonging to the genus Cosmarium
(Zygnematophyceae, Streptophyta), which were isolated from
various climatic zones and cultured long term (>15 years). The
photosynthetic behaviour and composition of photosynthetic
pigments of the Cosmarium strains were examined under low,
moderate and photoinhibitory white light by means of PAM
fluorometry, and high-performance liquid chromatography.
Generally, the Cosmarium strains displayed the photosynthetic
performance and pigment composition corresponding to that of
high-light adapted plants and algae. Yet, all the Cosmarium strains
demonstrated physiological responses that were consistent with
the light intensity prevailing at their source location as concluded
from chlorophyll fluorescence and changes of pigment composition,
confirming that these responses are genetically preserved.
Addition of inhibitors of chloroplast-encoded protein synthesis
(chloramphenicol and streptomycin) and violaxanthin de-epoxidase
(dithiothreitol) indicated that the Cosmarium strains developed
“sun- or shade-plant” protection strategies, in accordance with
the climate at their sampling sites. Strikingly, the typical arctic
taxon, C. crenatum var. boldtianum, displayed the incomplete
violaxanthin cycle yielding an accumulation of antheraxanthin
during high light stress, which is considered as an adaptation to
occasional high irradiances in the polar zone due to the albedo.
Antheraxanthin actively participated in the heat dissipation from
PSII centres in C. crenatum, as concluded from a significant positive
correlation between non-photochemical quenching and the quantity
of antheraxanthin. The species- and strain-specific ecophysiological
adaptations discussed in this study may enable desmids to cope with
In:
- Abstract Book: SEB Gothenburg 2017: Scientific Smärgåsbord; 2017 Jul 3-6; Gothenburg, Sweden. Lancaster: The Society for Experimental Biology; 2017. p. 59.