Maja Lazarević

Distribution and diversity of Arctic-Alpine species in the Balkans

The distributions of 77 Arctic-Alpine species in the Balkans are mapped and the centers of their richness and diversity presented. Within the Dinaric Alps these are Mts Vranica, Durmitor, and Prokletije; in the Scardo-Pindhic mountains, Šarplanina–Rudoka–Korab form a continuous chain; in the Rhodope-Rila mountain system there are Mts Vitoša, Rila, and Pirin; while in the Balkan mountain system there are the West and Central part of Stara planina. A comparison of floristic richness and distribution of Arctic-Alpine flora in relation to altitude, geographical location, and geological substrate is made. Correlations between floristic richness and geographical distance of the Balkan mountains from the two main centers of Arctic-Alpine flora in Central Europe are also provided.

Genetic, cytological and morphological differentiation within the Balkan-Carpathian Sesleria rigida sensu Fl. Eur. (Poaceae): A taxonomically intricate tetraploid-octoploid complex

Reconstruction of relationships among populations of the morphologically polymorphic and taxonomically intricate Sesleria rigida sensu Fl. Eur. based on Amplified Fragment Length Polymorphisms (AFLPs) revealed four clearly differentiated genetic groups that did only partly follow recent taxonomic concepts, but were strictly allopatric. While some of the previ- ously described taxa constitute distinct genetic entities, others have no taxonomic value. Synthesizing our AFLP data with ploidy-level information obtained from all genetically investigated individuals as well as with chromosome counts revealed that tetraploid individuals prevail, while octoploids occur only within S. filifolia. Lack of AFLP divergence between tetra- and octoploids suggests an autopolyploid origin of the latter. The genetic differentiation pattern was reflected by morphological differentiation, allowing for a taxonomic revision of the constituents of S. rigida sensu Fl. Eur. resulting in recognition of the four species S. achtarovii, S. filifolia, S. rigida, and S. serbica.

Resurrection plants of the genus Ramonda: prospective survival strategies – unlock further capacity of adaptation, or embark on the path of evolution?

Paleoendemic species of the monophyletic genus Ramonda (R. myconi, R. serbica and R.~nathaliae) are the remnants of the Tertiary tropical and subtropical flora in Europe. They are the rare resurrection plants of Northern Hemisphere temperate zone. Ramonda serbica and R. nathaliae are chorologically differentiated in the Balkan Peninsula and occupy similar habitats in calcareous, northward slopes in canyons and mountainsides. They remain well-hydrated during spring, late autumn and even in winter. In summer and early autumn when plants are subjected to drought and thermal stress, their desiccation tolerance comes into operation and they fall into anabiosis. Investigations revealed the permanent presence of ubiquitine and its conjugates, high amounts of oxalic acid and proline. Both species are homoiochlorophyllous. It enables them to rapidly resume photosynthesis upon rehydration, but also makes them susceptible to reactive oxygen species formation. Dehydration induces activation of antioxidative enzymes (ascorbate peroxidase, glutathione reductase, polyphenol oxidase), increase in amounts of AsA and GSH, phenolic acids, dehydrins, sucrose, and inorganic ions. Plasma membranes, characterized by high amount of cholesterol, are subjected to decrease in membrane fluidity mostly on account of increased level of lipid saturation. Cytogenetic analysis revealed that R. nathaliae is a diploid (2n = 48) and probably evolutionary older species, while R. serbica is a hexaploid (2n = 144). Two species live together in only two localities forming hybrid individuals (2n = 96). Polyploidization is the major evolutionary mechanism in the genus Ramonda that together with hybridization ability indicates that these relict species which have preserved an ancient survival strategy are not the evolutionary “dead end.”The species of the genus Ramonda are promising sources of data important for understanding the complex strategy of resurrection plants’ survival, appraised through a prism of their evolutionary and adaptive potential for multiple environmental stresses.