The vegetative arctic freshwater green alga Zygnema is insensitive to experimental UV exposure

Molecular and morphological diversity of Zygnema and Zygnemopsis (Zygnematophyceae, Streptophyta) from Svalbard (High Arctic)

“…(e.g. Kim et al ., 2008, 2011; Holzinger et al ., 2009). In this study, we confirmed the occurrence of Zygnemopsis (Pichrtová et al ., 2014 b ), and further determined the species as Zygnemopsis lamellata by morphological characterization of a fertile sample observed in the field.…”

“…The function of the ‘wings’ remains unclear, although pectic layers are common in Zygnematophyceae, and usually relate to the water-holding capacity, suggesting that the lamellate appendages could be beneficial when water availability is scarce during zygospore formation. Zygnema / Zygnemopsis mats have been frequently found to dry out during the vegetative season (Holzinger et al ., 2009; Pichrtová et al ., 2014 a ), which could result in incomplete zygospore development. The appendages may therefore help to overcome this problem in Zygnemopsis lamellata .…”

“…Transmission electron microscopy (TEM) was essentially performed as previously described (Holzinger et al ., 2009). The entire fixation and embedding procedure was performed immediately in Svalbard.…”

“…These polar hydro-terrestrial algal mats are often formed by algae of the genus Zygnema C. Agardh that are very well adapted to the harsh conditions of the polar climate, as demonstrated by various ecophysiological studies (Hawes, 1990; Holzinger et al ., 2009; Pichrtová et al ., 2013, 2014 a , 2014 b ; Vilumbrales et al ., 2013; Choi et al ., 2015). Nevertheless, both floristic and ecophysiological publications refer only to ‘ Zygnema spp.’ because species diversity within these mats remains unexplored.…”

“…Conjugation usually takes place only occasionally. In extreme environmental conditions conjugation is rare or never occurs, which is usually attributed to a trade-off between sexual reproduction and growth (Holzinger et al ., 2009), a phenomenon widespread in vascular plants (Eckert, 2002). With the exception of Zygnema cf.…”