Ljiljana Merkulov

Chemical Composition of Essential Oil and Leaf Anatomy of Salvia bertolonii Vis. and Salvia pratensis L. (Sect. Plethiosphace, Lamiaceae)

The taxonomical relationship between Salvia pratensis and S. bertolonii has been unclear for a long time. Salvia bertolonii has alternatively been considered a synonym, a subspecies, a problematic subspecies and a form of Salvia pratensis. However, both these two species are sometimes used in traditional medicine instead of sage (Salvia officinalis) or as an adulteration for the same drug. In order to confirm the status of S. bertolonii, together with the potential identification characteristics for differentiation from sage, both taxa were analyzed through the analysis of their essential oils, together with the micromorphological characteristics of the leaf surface and the anatomy and morphology of the leaves. The obtained results show that there are clear differences in the quantity of essential oil (0.073% for S. pratensis and 0.0016% for S. berolonii). The major compound in the essential oil of S. pratensis was E-caryophyllene (26.4%) while in S. berolonii essential oil caryophyllene oxide was the major component (35.1%). The micromorphological differences are also pronounced in the leaf indumentum (density and distribution of certain types of non-glandular and glandular trichomes). Clear distinction between the investigated Salvia species is also observed in the leaf anatomy (in S. pratensis leaves are thinner, palisade tissue is made of 1-2 layers of cells, and leaves of S. bertolonii are characterized by 2-3 layers of palisade tissue cells, and consequently thicker).

Comparative analysis of qualitative anatomical characters of Trifolium L. (Fabaceae) and their taxonomic implications: preliminary results

A comparative anatomical study of 20 Trifolium species was carried out using light and scanning electron microscopy in order to investigate the structure of their vegetative and reproductive organs and to evaluate the taxonomic significance of qualitative characters for distinguishing between the taxa. Characters were coded and analysed by multiple correspondence analysis. The combination of selected qualitative anatomical characters of the petiole, stipules, stem, peduncle and calyx (not previously studied in detail) were significant in delimiting sections of the genus Trifolium, but not for identification of species. The characters that contributed most to the separation of sections were peduncle cross-section shape, the presence of trichomes on the calyx tubes and the presence of trichomes and crystals in the stipules.

Anatomical Characteristics of Cherry Rootstocks as Possible Preselecting Tools for Prediction of Tree Vigor

An anatomical study of roots and stems of five self-rooted cherry rootstocks with different growth control potentials was performed to compare their structure and xylem anatomy. The aim was to correlate anatomical parameters with rootstock dwarfing potential and theoretical hydraulic conductance (kh), and to evaluate the potential application of anatomical characteristics in the preselection process for prediction of ultimate tree vigor. One of the mechanisms of water transport efficiency reduction in dwarfing rootstock stems is from the rootstock xylem anatomy. Anatomical parameters of ‘Gisela 5’ and ‘Mazzard’ were typical for dwarfing and vigorous rootstocks, respectively, and were thus suggested as reference rootstocks. Significantly greater vessel diameter and frequency were found in invigorating and dwarfing rootstocks, respectively. Higher kh was obtained in roots, compared to stems, due to significantly larger vascular elements. Dwarfing rootstocks had lower kh due to small vessel lumens and percentage and, to a lesser extent, because of low wood/cortex ratios or percentage of wood. A higher percentage of wood or xylem in cherry roots and stems was not always positively correlated with their conductivity and vigor. Thus, these parameters cannot be reliably used in prediction of the ultimate vigor, although this method was previously suggested for some other fruit tree species. The most reliable anatomical parameters for that purpose proved to be vessel frequency, vessel lumen area, and percentage of vessels on wood cross section. These characteristics could thus be an effective way to estimate dwarfing capacity and could be applied in rootstock selection and breeding programs.

Anatomical characteristics and antioxidant properties of Euphorbia nicaeensis ssp. glareosa

Anatomical analyses found that leaves of Euphorbia nicaeensis ssp. glareosa are isolateral, amphistomatous, with two layers of palisade cells on the adaxial and one on the abaxial side. Laticifers are present by vascular bundles, in palisade and spongy tissue. Stem laticifers are located in the pericyclic ring, adjacent to the phloem, in cylinder parenchyma and medullar rays. The structure of pleiochasium and dichasium peduncle is similar to the stem structure. Plants from typical steppe habitat show more xeromorphic features. Phytochemical screening of extracts showed presence of catecholes, flavonoids, tannins, saponins, free quinone derivatives and absence of anthocyanins, leucoanthocyanins, alkaloids, steroid compounds and essential oils. Our results showed that the examined taxon was partially susceptible to the action of reactive oxygen species, such as O2·− and ·OH. The higher quantities of ROS thus provoked an antioxidative response from the plant, both in an enzymatic and non-enzymatic manner. Stable anatomical structure, presence and distribution of laticifers and effective antioxidant properties when exposed to ROS, make Euphorbia nicaeensis subsp. glareosa potentially interesting for further pharmaceutical and phytochemical examinations.

Histological components of Trifolium L. species related to digestive quality of forage

The microscopic analysis of leaflet, petiole, stem and peduncle of 26 populations of 17 Trifolium species was carried out in order to examine their structural characteristics related to digestibility, to compare them between the populations of forage species and their wild relatives and to evaluate, from histological aspect, the potential of wild-growing species to be used as forages. Forage species had low proportion of the tissues composed of thick-walled cells and high proportion of the tissues composed of thin-walled cells in all examined plant parts. The reduction of the proportion of lignified xylem, sclerenchyma and sclerenchymatous interfascicular parenchyma, were suggested as basic selection criteria in breeding Trifolium species for improved digestibility. T. angulatum, T. medium and T. pannonicum proved to be very similar to the forage species in their histological composition, proportion of thick-walled and thin-walled cells and type of variation of the examined parameters. We believe that these species have some potential for use as forages in their own right, but aditional biochemical, physiological and morphological investigations should be conducted.

Morpho-anatomical differentiation of Suaeda maritima (L.) Dumort. 1827. (Chenopodiaceae) populations from inland and maritime saline area

Morphological analysis of four populations of Suaeda maritima was undertaken in order to examine the variation between populations from inland and maritime saline area, as well as between the two subspecies. Variability and significance of morpho-anatomical differentiation were examined using principal component analysis (PCA), discriminant component analysis (DCA) and cluster analysis. Plants of each population exhibited halomorphic and xeromorphic characteristics. The results of PCA and DCA showed that S. maritima subsp. prostrata and S. maritima subsp. maritima could be clearly separated based on their quantitative anatomical characteristics. Based on our analysis, climate and the amount of salt and ions in the soil, are important factors that enhance the adaptive potential of S. maritima.

MODIFIED STEREOLOGICAL METHOD FOR ANALYSIS OF COMPOUND LEAVES AND AN EXAMPLE OF ITS APPLICATION

Stereology, an interdisciplinary field that enables three-dimensional interpretation of planar sections, contains several methods for evaluation of quantitative parameters. The existing leaf sampling procedures were modified and adapted for compound, trifoliate leaves. The similar sampling method could also be applied on other types of compound leaves. Using Trifolium species as model species, we suggested the new way of application of this method in agronomy — precise determination of volume densities of indigestible lignified tissues (which determines forage digestibility), and of chlorenchyma and intercellulars (important for the photosynthesis). Comparison of the results obtained by classic anatomical analysis of leaf cross sections with the results of stereological analysis showed that both methods could be successfully applied for analysis of compact tissues (epidermis, vascular and mechanical). For the tissues that contained intercellulars (palisade and spongy), stereological method gave more precise results, as it enabled separate determination of volume density of intercellulars. A further advantage is that several leaf segments are analyzed and observed from four different angles. The obtained results opened new possibilities of application of stereological method in botanical and agricultural research, especially in prediction of digestibility and nutritional value of forages.

Variability of acorn anatomical characteristics in Quercus robur L. genotypes

The aim of this study was to examine variability of acorn anatomical characteristics in seventeen Quercus robur L. genotypes. Acorns were collected in clonal seed orchard Banov Brod (Srem, Vojvodina, Serbia). Microscopic measurements were done for pericarp (total thickness, thickness of exocarp and mesocarp), seed coat (total thickness, thickness of outer epidermis, parenchyma, and inner epidermis), and embryo axis (diameter, thickness of cortical region, and diameter of stellar zone). Obtained results revealed certain divergence between genotypes. The thickness of pericarp varied from 418 to 559 mm (genotypes 20 and 22, respectively). On average, the participation of exocarp in the total thickness of pericarp was 36.3%, of mesocarp 61.0%, while of endocarp 2.6%. The thickness of seed coat for individual genotypes ranged from 71 mm (genotype 28) to 157 mm (genotype 38). In addition, anatomic parameters of embryo axis varied among studied genotypes. The lowest cortical zone thickness and stellar zone diameter were measured in genotype 40, while the highest values in genotype 33.