Dolja Pavlova

Notes on karyomorphology of Melilotus officinalis popu- lations in Bulgaria

Abstract Karyological study was conducted on 9 populations of Melilotus officinalis (L.) Pall. collected from different floristic regions in Bulgaria. The karyotypes of the investigated populations are similar in their chromosomal morphology consisting of metacentric and submetacentric chromosomes. Three cytotypes are delimited on the base of differences in the composition of the karyotypes and marked chromosomal differences as to length and morphological features. A greater difference in the composition of the karyotype in one of the populations is connected with deviations in its macromorphology which are taxonomically presented by separation of a variety arenaria. This taxon is a local endemic and its populations should be placed under control and protection. From a taxonomic point of view the minor differences in the karyotypes established give reasons to consider these cytotypes as infraspecific taxa. The chromosomal polymorphism testifies the susceptibility of the karyotype to the environmental factors resulting in genome modifications.

Characteristics of Honey from Serpentine Area in the Eastern Rhodopes Mt., Bulgaria

Honey samples collected during 2007–2010 from serpentine and non-serpentine localities in the Eastern Rhodopes Mt. (Bulgaria) were characterized on the basis of their pollen content by qualitative melissopalynological analysis and physicochemical composition. Water content, pH, electrical conductivity, macroelements—K, Ca, Mg, P, and microelements—As, Cd, Co, Cr, Cu, Fe, Mn, Na, Ni, Pb, and Zn were determined after the Harmonised Methods of the International Honey Commission and ICP-AES method. The results from serpentine honey samples were compared with data from bee pollen collected from the same serpentine area. Different elements have different concentrations in honey from the same botanical type even collected from the same geographical region, same locality, and same beehive but in different vegetation season. The elements Mg, Mn, Ni, and P contribute mostly for separation of the serpentine honey samples based on measured elemental concentrations and performed principal component analysis. The element concentrations were higher in bee pollen and above the permissible limits for the toxic metals Cd and Pb. No specific indicator plant species was found for identification of the geographical origin of serpentine honey in relation to the forage of bees.

Essential and toxic element concentrations in Hypericum perforatum

The herb Hypericum perforatum L. - otherwise known as St Johns Wort - that grows on serpentine and non-serpentine sites is widely used in traditional medicine in Bulgaria. Plant aerial parts (Hiperici herba) as well as methanol/water (1:1) and water extracts prepared from eight populations growing on and off serpentine were analysed for essential (Fe, Mn, Cr, Co, Cu, Zn) and toxic (Ni, Cd, Pb) elemental concentration using inductively plasma optical emission spectrometry and electro thermal atomic absorption spectrometry. The results showed that metal concentrations variedacrosssites.Non-serpentinepopulationswerewellseparatedbasedontheirtotalmetalconcentrations.TheplantisNi tolerant,buthasthepotentialtoaccumulatetraceelementsattoxiclevels.Thetransferofelementsfromtheherbmaterialtoan extract was solvent and metal dependent. The highest mobility, e.g. percentages of extraction, was found for Cu, Zn and Ni inallextracts.TheamountofCd,NiandCrwasabovethepermissiblelimitsindryplantmaterialandbothtypesofextracts. The element concentrations found in this medicinal plant show that people should be careful when collecting it from serpentine sites and using it for medication.

Contribution to the knowledge of Bulgarian serpentine grasslands and their relationships with Balkan serpentine syntaxa

Serpentine areas, including those in Bulgaria, are rich in endemic taxa, and still remain to be investigated phytocoenologically. We analyse the vegetation types in various sites and compare them with those in other Balkan countries. The main objectives were (1) to explore and describe the relationships between the vegetation in the serpentine areas investigated in Bulgaria with those in the Balkan Peninsula and (2) to explore and classify the diversity of vegetation in grasslands on serpentine rocks in eastern Rhodope, Bulgaria. The classic methodology of the Braun-Blanquet school was applied to the exploration of the vegetation. Average linkage method (unweighted pair group method with arithmetic mean) and principal coordinate analysis were used to evaluate floristic and synoptic similarities. As a result, the new endemic association Onosmo pavlovae-Festucetum dalmaticae was proposed. This association can be included in the alliance Alyssion heldreichii Bergmeier et al. 2009, newly described on serpentine rocks in northern Greece. Our data confirmed the existence of similar or vicariant endemic syntaxa (associations) on isolated serpentine terrains in northern Greece and south-eastern Bulgaria.

Variation in morphology of Teucrium polium aggr. populations in Bulgaria

The aim of this study was to investigate natural serpentine and non-serpentine populations of Teucrium polium aggr. and to document the differences in their morphological traits, as well as estimate which characters are most likely contributing to differentiation of the populations. Nine populations distributed both on and off serpentine soils were investigated, and 12 different morphological features of 270 individuals were studied by univariate and multivariate statistical analyses. The results did not demonstrate clear delimitation of the serpentine from the non-serpentine populations. Using these ecotypes as classification factors in the discriminant analysis, it can be stated that stem height, leaf length in the fifth leaf pair, internode length between the fourth and the fifth leaf pairs, and corolla tube length are features with the greatest discriminant ability. The character variation was generally higher for the vegetative features, while reproductive features failed to demonstrate clear differences. The similarity groupings indicated by the cluster analysis were synchronous with groups distinguished by both the discriminant and PCA analyses. Significant differences were observed between sets of vegetative characters in all populations investigated.

Element Case Studies: Nickel

Initial experiments using Mediterranean Ni-hyperaccumulator plants for the purpose of phytomining were carried out in the 1990s. In order to meet commercial phytoextraction requirements, a technology has been developed using hyperaccumulator species with adapted intensive agronomic practices on natural Ni-rich soils. Ultramafic soils in the Balkans display a great variability in Ni concentrations and available Ni levels, both in Albania and the Pindus Mountains of Greece. In Albania, Vertisols are currently being used for low-productivity agriculture (pasture or arable land) on which phytomining could be included in cropping practices. Alyssum murale occurs widely on these ultramafic Vertisols and is a spontaneous weed that grows among other crops. This review chapter presents the different steps that were investigated during the study of soil suitability, and selection of plants up to optimization of agronomic practices, at field scale, as recently developed to reach the implementation stage of Ni agromining in Albania. During a 7-year study we addressed the following questions: (i) what are the optimal soils for Ni agromining in terms of fertility and Ni availability? (ii) what is the phytoextraction potential of local populations of Ni hyperaccumulator species? (iii) what should be the agronomical practices used to optimize the cropping of A. murale for extensive phytomining adapted to a Balkan agricultural setting?

Pollen morphology and localization of Ni in some Ni-hyperaccumulator taxa of Alyssum L. (Brassicaceae)

Pollen morphology of seven Alyssum L. taxa growing on serpentine soils in different places in the European Mediterranean macrobioclimate territory were studied, described and compared. Cluster analysis was performed to show similarity between species and their populations. The shape of the pollen grains varies among the species and among the grains within the same anther. The pollen grains are 3-colpate, prolate, with long and narrow colpi reaching the poles. The ornamentation of the exine varies from micro-reticulate to reticulate between the species. Pollen sterility/fertility was also calculated. The highest percentage of sterile pollen (73.76%) was calculated for Alyssum murale subsp. murale and the lowest (9.54%) for A. bertolonii subsp. bertolonii. All species are representatives of sect. Odontarrhena (C.A. Meyer) Koch well known as Ni-hyperaccumulators. Nickel and other elements present in pollen and stamen were studied by inductively coupled plasma-mass spectrometry. The stamen parts of all species were micromorphologically analyzed by scanning electron microscopy coupled to an energy-dispersive X-ray probe. Accumulation of Ni was detected in the stamens of all studied species and rarely in the pollen grains. The distribution patterns of Ni were similar among the species examined.

Oxytropis kozhuharovii (Fabaceae), a new species from Bulgaria

Abstract Pavlova, D., Dimitrov, D. & Nikolova, M.: Oxytropis kozhuharovii (Fabaceae), a new species from Bulgaria. — Willdenowia 29: 69–75. 1999. — ISSN 0511-9618. Oxytropis (sect. Orobia) kozhuharovii from the Pirin Mts in SW Bulgaria is described as a species new to science and illustrated. Its karyotype has been investigated and a chromosome number of 2n = 4x = 32 found. The morphological differences to O. prenja and O. halleri are analysed and illustrated.

Nickel effect on root-meristem cell division in Plantago lanceolata (Plantaginaceae) seedlings

The toxic effect of nickel (Ni) on cell division on root-meristem cells in seedlings of Plantago lanceolata L. was studied and compared. Seed material was collected from serpentine and non-serpentine populations of the species distributed in the Rhodope Mountains, Bulgaria. The root-tip meristem cells of germinated seeds were treated with different solutions of 0.01, 0.025, 0.05, 0.1 mM Ni as NiSO4 6H2O with distilled water for 24 h and 48 h respectively. The mitotic index decreased when Ni concentrations and exposure time increased in both type of samples. Significant differences in the mitotic indexes were found between the controls and the roots treated with Ni. The mitotic index was higher in root-meristem cells of serpentine seedlings. C-mitosis, anaphase bridges, chromosome stickiness, laggards and extrusion of nuclear material into the cytoplasm were observed in the root-tip cells treated with Ni. The percentage of aberrations generally increased in a concentration- and time-dependent manner. The percentage of the extruded nuclei was higher in cells treated with 0.05 and 0.1 mM Ni. It can be concluded that P. lanceolata seedlings on serpentine can tolerate higher Ni concentrations than can non-serpentine seedlings.

Spontaneous flora of the Rila Monastery (Bulgaria)

The spontaneous flora of the largest and most popular Rila Monastery, symbol of Bulgaria, included in the UNESCO World Heritage list was investigated during 2008–2012. The objectives of the study were to explore species composition and to characterize the plants spontaneously spread in the inner court of the monastery. The total number of the found vascular plants is 110 species from 43 families and 94 genera. The analysed group included predominantly native species, perennial plants – hemicryptophytes (61 species; 58.65%). The most common species were classified into three groups: (1) species, typical for the rocks flora; (2) common species with wide ecological amplitude and high colonization possibilities; and (3) species, typical for the flora surrounding the monastery. Frequently found species were Sclerochloa dura, Poa annua, Polygonum aviculare, Plantago major, Trifolium repens, Agrostis capillaris, Geum urbanum and Stellaria media. The distribution of the species is a result of specific ecological conditions, such as soil moisture and quantity, lightening of the site area during the day, exposition and intensity of use. The anemochoric woody species (Acer pseudoplatanus, Acer heldreichii, Fraxinus excelsior, and Ulmus glabra) found in the court as seedlings were also observed on the walls and roof of the Hrelyos Tower, which can cause severe damage to the buildings and problems for the conservation of the archaeological monuments.