Photophysiological investigations of the temperature stress responses of Zygnema spp (Zygnematophyceae) from subpolar and polar habitats (Iceland, Svalbard). Issue 3 (4th May 2022)

• Record Type: Journal Article
• Authors: Permann, Charlotte; Pierangelini, Mattia; Remias, Daniel; Lewis, Louise A.; Holzinger, Andreas
• Is Part Of: Phycologia. Volume 61:Issue 3(2022)
• Page Start: 299
• Page End: 311
• Publication Date: 2022-05-04
• Subjects: Climate change -- Green algae -- Photosynthesis -- rbcL phylogeny -- Streptophyta -- Transmission electron microscopy; Algology -- Periodicals; Algae -- Periodicals; Algae; Natuurkunde; Algae; Periodicals; Electronic journals; 579.805
• DOI: 10.1080/00318884.2022.2043089
• Languages: English
• ISSNs: 0031-8884

Abstract

ABSTRACT: Zygnematophyceae are main primary producers in polar hydro-terrestrial habitats, characterized by extreme abiotic conditions. They are expected to be strongly impacted by climate change, leading to threats to subpolar and polar ecosystems. Two isolates of Zygnema from a subpolar (Iceland, Zygnema sp. I) and a polar Island (Svalbard, Zygnema sp. B) were compared by their photophysiological performance and phenolic content. A phylogenetic analysis was performed in a newly isolated Zygnema I where also morphology and ultrastructure were characterized. The rbc L sequence of the Icelandic Zygnema I was identical to that of Zygnema V, previously isolated from Svalbard, and phylogenetic analysis placed this strain into Zygnema clade 2. Average width of vegetative filaments (28 ± 0.7 µm) and ultrastructure was similar to closely related Zygnema strains. Zygnema I and Zygnema B were exposed to three different treatment temperatures (15, 20 and 25°C) for two weeks, then photophysiological parameters and cellular phenol contents were acquired. The maximum electron transport rate increased significantly with elevated temperatures, but non-photochemical quenching did not change. Net photosynthetic oxygen production was higher in Zygnema B, but decreased in both strains from 10 to 15°C measuring temperature. Zygnema I showed a significant decrease between 15/25°C-treated cultures above 20°C measuring temperature. The phenolic content did not change significantly with experimental treatments, the spectral absorption at 350 nm was significantly lower in Zygnema B when compared with Zygnema I. Taken together our results indicate that Zygnema B and Zygnema I cannot adapt to elevated temperatures.