Photosynthetic electron transport at low temperatures in the green algal foliose lichens Lasallia pustulata and Umbilicaria hirsuta affected by manipulated levels of ribitol

Abstract

In lichens, ribitol is known as a carbon storage compound, an osmotic agens involved effectively in cell compartments protection during dehydration of lichen thalli and as a cryoprotective compound. In our study, we investigated the effect of ribitol on photochemical processes of photosynthesis in foliose lichens [Lasallia pustulata (L.) Mérat., Umbilicaria hirsuta (Sw. ex Westr.) Hoffm.] at low temperature. The effects of three concentrations of ribitol, added externally to thalli segments on several chlorophyll (Chl) fluorescence parameters, were evaluated. The 72 h exposition to 8, 16, and 26 mM ribitol led to a concentration-dependent increase in F V /F M , decrease in non-photochemical quenching (NPQ) but no change in quantum yield of photosystem II photochemistry (Φ PSII ) values at -5 o C). At higher temperature (0, +5 o C), no effect of ribitol addition on the photosynthetic parameters was apparent.

Cryoproective role of ribitol in Xanthoparmelia somloensis

“…Thus, ribitol may have positive effect on primary photosynthetic processes in lichens when added in the concentrations ranging between 8 -32 mM. Such conclusion might be supported also by the decrease in NPQ caused by 8 -32 mM ribitol (Hájek et al 2009) while it was Fig. 3.…”

“…Fontaniella et al 2000). In our previous study (Hájek et al 2009), we showed that addition of ribitol improved photosynthetic activity of two foliose lichen species (Lasallia pustulata and Umbilicaria hirsuta) at freezing temperature. In recent experiments, we have focused on utilization of ribitol in synthesis of lichen secondary metabolites.…”

“…This was well documented in our experiment, since positive effect of ribitol addition on F v /F m and Φ PS2 was found exclusively in thalli segments treated at -5 °C and 0 °C. However, concentration-and species-specific differences were experienced; e.g Hájek et al (2009) found positive effect of 8, 16, and 26 mM ribitol concentration on F v /F m in Lasallia pustulata and Umbilicaria hirsuta. In contrast, in this study carried out on X. somloensis we showed that increase in ribitol concentration to 50 mM inhibited F v /F m in thalli treated at -5 °C.…”

Responses of thallus anatomy and chlorophyll fluorescence-based photosynthetic characteristics of two Antarctic species of genus Usnea to low temperature

“…Particular physiological responses to limiting environmental factors, such as resistance to photoinhibition (Balarinová et al 2014), temperature (Colesie et al 2018), freezing tolerance (Hájek et al 2016), and strategies of water uptake, and dehydration resistance (Jonsson Čabrajić et al 2010), were studied as well. Last but not least, several studies have addressed photosynthetic performance evaluated by gas exchange (Kappen et al 1995, Cao et al 2015, chlorophyll (Chl) fluorescence exploiting (1) fast (OJIP) transients (Bednaříková et al 2020a,b), (2) slow Kautsky kinetics with quenching analysis (Hájek et al 2001(Hájek et al , 2009 or (3) monitoring of in situ effective quantum yield of PSII (Cho et al 2020). Some studies combine gas exchange and Chl fluorescence measurements (e.g., ten Veldhuis et al 2020).…”

A method of water-soluble solid fraction saturation concentration evaluation in dry thalli of Antarctic lichenized fungi, in vivo

“…The accumulation of monosaccharides and polyols in lichen mycobiont is an adaptive feature for dealing with the complete dehydration [20] , [21] . Ribitol level modifies the photosynthetic activity in some green algal foliose lichens [22] .…”