The Antarctic lichen, Xanthoria elegans, in its hydrated state has several physiological mechanisms to cope with high light effects on the photosynthetic processes of its photobionts. We aim to investigate the changes in primary photochemical processes of photosystem II in response to a short-term photoinhibitory treatment. Several chlorophyll a fluorescence techniques: (1) slow Kautsky kinetics supplemented with quenching mechanism analysis; (2) light response curves of photosynthetic electron transport (ETR); and (3) response curves of non-photochemical quenching (NPQ) were used in order to evaluate the phenomenon of photoinhibition of photosynthesis and its consequent recovery. Our findings suggest that X. elegans copes well with short-term high light (HL) stress due to effective photoprotective mechanisms that are activated during the photoinhibitory treatment. The investigations of quenching mechanisms revealed that photoinhibitory quenching (qIt) was a major non-photochemical quenching in HL-treated X. elegans; qIt relaxed rapidly and returned to pre-photoinhibition levels after a 120 min recovery. We conclude that the Antarctic lichen species X. elegans exhibits a high degree of photoinhibition resistance and effective non-photochemical quenching mechanisms. This photoprotective mechanism may help it survive even repeated periods of high light during the early austral summer season, when lichens are moist and physiologically active.

Lichens can survive and cope with unsufficient water supply resulting in low intrathalline relative water content. Under such conditions, photosynthesis is negatively affected by different degree of dehydration. In our study, fully hydrated samples of Xanthoria elegans, Umbilicaria decussata and Usnea aurantiaco-atra were light-acclimated and during following desiccation from a fully hydrated to dry state, steady-state chlorophyll fluorescence (FS), effective quantum yield of photochemical processes in PSII (ФPSII), and nonphotochemical quenching (qN) were measured in response to decreasing relative water content (RWC). The three experimental lichen species showed a high desiccation tolerance. The desiccation-induced decrease in ФPSII was found in X. elegans, U. decussata and U. aurantiaco-atra, at the RWC values below 30%. This is well comparable to the evidence reached in other Arctic / Antarctic lichen species. Interspecific differences in desiccation tolerance of these selected Antarctic lichens, based on the analysis of photosystem II effectivity and quenching mechanisms, were described and discussed.

Use of cold for preservation of biological materials, avoidance of food spoilage and to manage a variety of medical conditions has been known for centuries. The cryobiological science justified these applications in the 1960s increasing their use in expanding global activities. However, the engineering and technological aspects associated with cryobiology can be expensive and this raises questions about the abilities of resource-restricted low and middle income countries (LMICs) to benefit from the advances. This review was undertaken to understand where or how access to cryobiological advances currently exist and the constraints on their usage. The subject areas investigated were based on themes which commonly appear in the journal Cryobiology. This led in the final analysis for separating the review into two parts, with the first part dealing with cold applied for biopreservation of living cells and tissues in science, health care and agriculture, and the second part dealing with cold destruction of tissues in medicine. The limitations of the approaches used are recognized, but as a first attempt to address these topics surrounding access to cryobiology in LMICs, the review should pave the way for future more subject-specific assessments of the true global uptake of the benefits of cryobiology.

Lichens from the cold regions of Earth exhibit high, but different degree of tolerance to drought and freeze stresses. Therefore, three lichen species Xanthoria elegans, Umbilicaria cylindrica, Usnea sphacelata, and a representative of extremophilic cyanobacteria Nostoc commune were selected to measure temperature response curves of chlorophyll fluorescence parameters in cooling experiment using a constant rate of cooling from 20 to –45°C. Two chlorophyll fluorescence parameters (FV/FM – potential yield of photosynthetic processes in photosystem II and ΦPSII – effective quantum yield) were measured with a modulated fluorometer. For all experimental species, the temperature-response curves of II FV/FM and ΦPSII showed typical triphasic shape: plateau (temperature decrease from 20 to –5°C), decline, and a shoulder reaching the critical point. The phase typically formed a S-curve of different shape as dependent on species and chlorophyll fluorescence parameter. U. cylindrica was the most cryoresistant in terms of photosynthetic processes ongoing in thylakoid membrane of chloroplast at below zero temperature.

Spectral characteristics of the bryophyte carpet and mat subformation on Nelson Island (South Shetlands Islands) and Galindez Island (Argentine Islands, Graham Coast) were analyzed using spectral reflectance characteristics. A set of 9 specific reflectance indices were calculated and compared between two locations for the same type of moss vegetation formed by Sanionia georgicouncinata and Warnstorfia spp. The Normalized Difference Vegetation Index (NDVI) is efficient in discriminating between the two contrasting color/ecological moss community classes, i.e. such as less vigorous or dead and vigorous. However, NDVI is not sufficiently sensitive to discriminate intermediate vitality states. Presented data also demonstrates that complementary application of two indices, NDVI and Photochemical Reflectance Index (PRI), can be promising for follow-up studies focused on the determination of the color differences attributed to ecolophysiological state of a moss community. With the same values of NDVI, bryophyte carpet and mat subformation on Galindez Island are characterized by higher values of the OSAVI, which can be used as an indicator for further monitoring.

Plasma Membrane Permeability of Carp (Cyprinus carpio, L., 1758) Spermatozoa for Water and Cryoprotectants Molecules at Different Stages of Cryopreservation