Genome size and chromosome number are characteristic species trait important in systematics, taxonomy and evaluation of biodiversity. The Adriatic coast of Croatia presents a unique area for biological and chemical research of plant material. Genus Centaurea (Asteraceae family) is already known for many medicinal plants that present a valuable source of potential medicines. In Croatia 79 Centaurea taxa have been listed, comprising 27 endemics. Previous chemical and biological observations of extracts and volatiles isolated from Centaurea species, showed differences in chemical composition and biological activity of volatile substances between different species. Some Centaurea species have many similarities in their morphological appearance, therefore the criteria of genome size and number of chromosomes contribute to plant material identification. Due to a high demand for a clear and authentic plant material identification in chemical research, genome size and number of chromosomes for six Centaurea species have made prior to chemical and biochemical research of isolated plant extracts. The genome size was estimated using flow cytometry. The chromosome number was determined using the standard karyological methods. The plant samples, seeds and leaves, were collected from wild growing natural populations of Croatia. The studied species present three basic chromosome numbers, x= 9, 10 and 11. The ploidy level of investigated species was diploid and tetraploid. Centaurea cristata and C. rhenana were tetraploid, whilst other species were diploid. The nuclear DNA amounts (2C DNA) range from 1.70 to 3.57 pg. Using the Leitch's et al. criteria all these taxa belong to the group of very small genome size. The results present the novel values for C. cristata, and C. rhenana. The studied species will be the object of our future studies concerning the chemical composition of volatile and non-volatile plant extracts and their biological activity and differences in chemical composition due to a level of ploidy.

Abstract Sisyrinchium micranthum and S. rosulatum are part of a species complex in which S. micranthum displays considerable morphological variation. S. rosulatum is a tetraploid species, whereas S. micranthum plants may present three different ploidy levels (2x, 4x, and 6x), so that polyploidy might have an important role in the diversification of this group. Notwithstanding, most cytogenetic studies on these species are based on chromosome counting. Aiming to understand how polyploidy may have impacted the genomes of these species, the DNA content of 184 specimens was estimated; fluorochrome banding with chromomycin A3 and fluorescent in situ hybridization using an 18S-5.8S-26S ribosomal DNA (rDNA) probe were also performed. The results showed a reduction in monoploid genome size (1Cx), as well as in the number of heterochromatin bands and rDNA sites per monoploid genome, from diploids to polyploids. Additionally, intraspecific and within-ploidy variations in genome size and number of rDNA sites were observed. The source of varying structure in genome organization of these plants may be the multiple independent formations of polyploids along with an ongoing diploidization process. However, the intraspecific and within-ploidy polymorphisms indicate genetic mechanisms other than genome duplication and diploidization to be important to the genome evolution of these taxa.

Seven Centaurea species from Croatia ( C. alba , C. calcitrapa , C. cristata , C. rhenana , C. rupestris , C. salonitana and C. solstitialis ) belonging to five sections were studied. Chromosome numbers and metaphase plates are presented. All species studied here were found to be either diploid or tetraploid with the exception of C. salonitana which presented both ploidy levels: one diploid and one tetraploid population were detected

UDK: 577.13:582  Plants produce a numerous and diverse secondary metabolites, organic compounds which are not essential and do not participate directly in the growth and development, but may have very important role in their adaptation and adjustment to particular environmental conditions. For humans, secondary metabolites are very important in medicine, pharmacology, food and cosmetics industries. The presence of eight types of secondary metabolites (anthocyanins, coumarins, emodins, fatty acids, phenols, saponins, steroids and tannins) in water extracts of leaves and barks of 25 broadleaf deciduous species from 15 families was qualitatively investigated by rapid phytochemical screening methods. According to literature data, in this study for the first time is determined the presence of six types of secondary metabolites in analyzed dendro species: anthocyanins in one species; both coumarins and phenols in five species; emodins in six species; saponins in eight species; and tannins in four species. Particular attention in further research should be given to Fagus sylvatica L., Populus tremula L., Quercus petraea (Matt.) Liebl., Robinia pseudoacacia L. and Sorbus aria (L.) Crantz. Since preliminary results of this study are promising it would be desirable both to identify active compounds and assess their potential antimicrobial and antioxidant activities.

Three endemic Centaurea species from North Africa are investigated for the first time by chromomycin fluorochrome banding for GC-rich DNA distribution, fluorescence in situ hybridization for physical mapping of rRNA genes, and flow cytometry for genome-size assessment. Investigated species belong to three different sections and possess three basic chromosome numbers: C. tougourensis subsp. tougourensis 2n = 4x = 36 (x = 9), C. musimonum 2n = 2x = 20 (x = 10), and C. maroccana 2n = 2x = 24 (x = 12). The number and distribution of chromomycin positive bands (CMA+) and 18S-5.8S-26S (35S) rDNA loci were different among investigated species and ranged from 6 to 80 chromomycin bands and from 2 to 6 35S rDNA loci. The three species have just one 5S rDNA locus at intercalary position on a separate chromosome pairs, except in the case of C. musimonum in which both rDNA loci were localized on the same chromosome. All rDNA loci were co-localized with CMA+ bands, except three 35S in C. musimonum. Genome size ranged from 2C = 1.66 to 2C = 2.86 pg in diploid species (C. musimonum and C. maroccana, respectively) and to 2C = 4.51 pg in tetraploid C. tougourensis subsp. tougourensis.

BACKGROUND AND AIMS Allopolyploidy and intraspecific heteroploid crosses are associated, in certain groups, with changes in the mating system. The genus Sorbus represents an appropriate model to study the relationships between ploidy and reproductive mode variations. Diploid S. aria and tetraploid apomictic S. austriaca were screened for ploidy and mating system variations within pure and sympatric populations in order to gain insights into their putative causalities. METHODS Flow cytometry was used to assess genome size and ploidy level among 380 S. aria s.l. and S. austriaca individuals from Bosnia and Herzegovina, with 303 single-seed flow cytometric seed screenings being performed to identify their mating system. Pollen viability and seed set were also determined. KEY RESULTS Flow cytometry confirmed the presence of di-, tri- and tetraploid cytotype mixtures in mixed-ploidy populations of S. aria and S. austriaca. No ploidy variation was detected in single-species populations. Diploid S. aria mother plants always produced sexually originated seeds, whereas tetraploid S. austriaca as well as triploid S. aria were obligate apomicts. Tetraploid S. aria preserved sexuality in a low portion of plants. A tendency towards a balanced 2m : 1p parental genome contribution to the endosperm was shared by diploids and tetraploids, regardless of their sexual or asexual origin. In contrast, most triploids apparently tolerated endosperm imbalance. CONCLUSIONS Coexistence of apomictic tetraploids and sexual diploids drives the production of novel polyploid cytotypes with predominantly apomictic reproductive modes. The data suggest that processes governing cytotype diversity and mating system variation in Sorbus from Bosnia and Herzegovina are probably parallel to those in other diversity hotspots of this genus. The results represent a solid contribution to knowledge of the reproduction of Sorbus and will inform future investigations of the molecular and genetic mechanisms involved in triggering and regulating cytotype diversity and alteration of reproductive modes.

UDK: 581.19:547.56:582.477 Various phenolic compounds can be found in a gymnosperms and have been related to their bioactive properties, esspecially as a allelochemicals. Total phenol, flavonoid (flavone and flavonol) and protoanthocyanindin content was estimated quantitatively by using spectrophotometric method in the needle methanol extracts of mature Cryptomeria japonica, Cupressocyparis × leylandii „Castewellan Gold“ and Sequoiadendron giganteum individuals. Although there is a strong intraspecific variability on the basis of the studied group of compounds, Duncan's test showed that C. japonica is clearly distinguishable from the other two taxa analyzed, and in particular on the basis of total proanthocyanidins and phenolics content. On the other hand, S. giganteum and C. × leylandii only differ on the basis of the flavonoid content calculated in terms of quercetin equivalent. In all three taxa proanthocyanidins had the highest variability. The ratios and relatively high content of analyzed phenolic compounds for all three studied taxa indicate that they may be considerd as a potential both chemotaxonomic characters and valuable sources of antioxidants, which should be confirmed by further researchs.

Four taxa of Algerian Astragalus L. were studied for their chromosome number, karyotype features, and genome size. Fluorochrome banding was done for detection of GC-rich DNA regions, fluorescence in situ hybridization (FISH) for physical mapping of 35S and 5S rRNA genes, and flow cytometry for nuclear DNA content. All the taxa present the same chromosome number (2n = 2x = 16) and single 35S and 5S rDNA loci, but their distributions on chromosomes are different. The GC heterochromatin pattern was different among studied taxa and an unusually high number of chromomycin-positive bands were observed in A. pseudotrigonus Batt. & Trab. The genome size differed between species, ranging from 2C = 1.39 pg in A. cruciatus Link. to 2C = 2.71 pg in A. armatus subsp. tragacanthoides (Desf.) Maire. No difference in nuclear DNA amount was detected between the 2 subspecies of A. armatus. Although Astragalus is a large genus comprising some 3000 species, such morphometric and molecular cytogenetic karyotype analyses, with genome sizes, are particularly scarce therein. Therefore, published genome sizes have also been compiled into one table.

UDK: 582.632.1:581.45(497.6) Natural interspecies hybrids of black (Alnus glutinosa (L.) Gaertn) and grey (A. incana (L.) Moench) alder are not frequent in nature but they are registered, and according to modern systematic nomenclature are classified within nothospecies A. × pubescens Tausch.. Since the presence of spontaneous intermediate forms of the genus Alnus in Bosnia and Herzegovina is insufficiently explored, the first results of comparative morphological analysis (seven leaf’s characters) of black and grey alder and their hybrids are given in this study. About 10% of hybrid individuals were present in the studied sympatric populations, and they had more heterogeneous leaves than parental species. Good diagnostic characters showed intermediate values in comparison to the parental species, which are: number of pairs of lateral veins, angle from the top of the leaflet to the top of the upper 3rd nerve, and distance from the top of the leaflet to the top of the upper 3rd vein. According to analyzed characters, hybrids either hold intermediate positions between the parental species or are closer to the maternal species (A. incana). Three new findings of nothospecies A. × pubescens for Flora B&H are rivers’ localities Drinjača near Kladanj, Turbe near Travnik, and Stavnja near Vareš. Due to the low frequency of observed individuals of A. x pubescens, they are vulnerable and require special measures of protection and biodiversity conservation activities of autochthonous gene pool, it is necessary to determine the actual state in all previously published hybrid complexes’ findings and expand researches in B&H in the coming period.

It is difficult to distinguish hysteranthous Colchicum species growing in Dalmatia and Bosnia and Herzegovina, even the two most common taxa (C. autumnale and C. neapolitanum subsp. visianii). There are no clear vegetative characteristics suitable for good identification of these species. The nuclear DNA values, however, reveal differences between these two species and also among other taxa. Genome size was studied for the first time in: C. hungaricum Janka (2C = 5.38 ± 0.3 pg); two Dalmatian endemics C. neapolitanum (Ten.) Ten. subsp. kochii (Parl.) Fridl. (2C = 10.9 ± 0.3 pg) and C. neapolitanum (Ten.) Ten. subsp. visianii (Parl.) Fridl. (2C = 10.41 ± 0.32 pg) and for Italian C. neapolitanum (Ten.) Ten. subsp. neapolitanum (2C = 10.0 ± 0.1 pg) endemic to Basilicata - Campania. Genome size of C. autumnale L. from Bosnia and Herzegovina (2C = 6.17 ± 0.31 pg) does not differ from other west European populations. Based on this important character and also on morphological studies, we propose taxonomic revision of some taxa. As genome sizes of the two generally confused species C. neapolitanum subsp. visianii and C. autumnale are very different, flow cytometry is useful for identification, conservation inventories and management concerning these two taxa.