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Variability in the contents of representative secondary metabolites in Gentiana pneumonanthe individuals was investigated in relation to population origin, plant parts and developmental stage. Chem...

Natural populations of Gentiana asclepiadea L., located at two mountainous sites, were HPLC-analyzed regarding the contents of six representative secondary metabolites. The contents of swertiamarin (SWM), gentiopicrin (GP), sweroside (SWZ), mangiferin (MGF), isoorientin (ISOOR), and isovitexin (ISOV) were determined in six populations (three per study site), and separately for aboveground and belowground plant parts. PCA showed a clear separation of four groups according to the contents of the analyzed secondary metabolites. Out of six analyzed compounds, five were present in all samples and only one (SWZ) was found in Golija populations (belowground parts) but not in Vlasina populations, and its presence can be indicative of the geolocation of populations. Clear separation of groups was mostly affected by the different contents of chemical compounds in plant parts (aboveground versus belowground) and by the differences related to population origin (higher content of SWM and GP in belowground parts of individuals from Vlasina populations and higher content of MGF and ISOOR of individuals from Golija populations). The results of this study contribute to the spatiochemical profiling of G. asclepiadea populations and a better understanding of inter- and intrapopulation variability of pharmacologically important compounds.

Many biological and related disciplines recognize population as a carrier of species-specific characteristics adapted to habitat requirements. Within a species’ area of distribution, a wide range of biotic and abiotic factors synergistically shape different habitats, and plant populations develop a set of specific features to respond to given environmental conditions. Distinct populations with phenotypic differences determine the ecotypes within the taxon. Similarly, the chemotype is defined as a chemically distinct plant population, according to the composition of secondary metabolites. Many secondary metabolites have pronounced biological activities and implications for human health. With respect to searching for new sources of secondary metabolites with potential health effects, natural populations of plant species attract the substantial attention of researchers because their habitats are highly diverse and unpolluted. Many studies on this subject have confirmed the biological and chemical diversity of natural populations and emphasized the need for the conservation of natural resources.

Inter- and intrapopulation variability in six natural populations of the rare species Gentiana pneumonanthe was examined based on morphological and chemical data. Population size and linear morphometric parameters differed significantly among populations, but without a clear connection to habitat conditions, i. e. water supply and light availability. Leaf shape varied from ovate to lanceolate in all populations, and one population was distinctive in having the largest number of leaves of transitional shape. HPLC analyses of six secondary metabolites were performed separately for belowground parts, and aboveground vegetative and reproductive parts of individual plants (6 populations ×7 individuals ×3 plant parts, n=126) in order to examine differences at the population and individual levels. Three secoiridoids (swertiamarin (SWM), sweroside (SWZ), and gentiopicrin (GP)), one xanthone (mangiferin (MGF)), and two flavones (isoorientin (IO) and isovitexin (IV)) were detected and quantified in the analyzed samples: sweroside dominated in the aboveground reproductive part, mangiferin in the aboveground vegetative part, and gentiopicrin in the belowground part. At the population level, differences in contents of the analyzed chemicals among populations were significant only for a few metabolites. At the individual level, a pronounced organ-dependent distribution of secondary metabolites was revealed. The results of this study contribute to a better understanding of natural variability within populations of the rare and threatened G. pneumonanthe, and provide data on the contents and within-plant distribution of secondary metabolites, which are important as pharmacologically active compounds and may be useful for further biotechnological procedures regarding this species.

Forests influence humans’ life and health in many ways, by regulating specific climatic conditions, oxygen production, global carbon cycle, and by influencing the conditions for social human activities. Forest biodiversity is crucial for maintaining ecological and societal functions. Disturbances in forest vitality and biodiversity cause complex chain of reactions regarding biotic interactions which involve some animal vectors of zoonotic diseases and lead to increased incidences of zoonoses in human population. The disturbance of native forest ecosystems usually occurs through deforestation and landscape modification for other purposes, especially agricultural. Fragmentation of forests and emergence of transitional zones reduce the capacity of ecosystems to self-regulate functions, for example, when food chains between predators and disease vectors are disturbed, leading to emergence of new pathogens. The integration of multiple datasets including land use change by usage of satellite imagery and field data, forest vitality, and biodiversity may contribute to better understanding the dynamics of incidence of some zoonotic diseases. This article aimed to compare ecological datasets with the incidence of Lyme disease and trichinellosis in Serbia for the period 1990–2012.

PCR-RAPD markers revealed individual variation in F. ornus. A total of 122 fragments were amplified using 7 primers and of these 97 fragments were polymorphic. The percentage of polymorphic loci was between 53.3% and 74.6% with an average of 63.1%. The mean gene diversity for all populations was 0.30 and the mean Shannon’s index was 0.44. Of the total genetic variation 87% was intra-population whilst 13% was inter-population. The Mantel test revealed significant correlation between genetic and geographical distance matrice. Results herein represent the first use of molecular genetic (DNA) markers to characterize genetic variation in F. ornus populations. The partition of total genetic variance indicates a relatively restricted population differentiation as expected in outcrossing species. Present and future information on genetic structure and variability in F. ornus needs to be incorporated into strategies for the preservation of genetic resources of tree species. [Projekat Ministarstva nauke Republike Srbije, br. 173011]

The composition of the essential oil of the twigs and needles of Taxus baccata L. from three natural populations in Serbia has been determined by GC/MS analysis. Of the 91 detected compounds, 87 were identified. The most abundant compound classes were aliphatic alcohols, terpenes, aliphatic hydrocarbons, and aliphatic aldehydes, which together comprised ca. 86.92% of the total oil composition. The dominant constituents were oct-1-en-3-ol (23.48%), (3Z)-hex-3-en-1-ol (11.46%; aliphatic alcohols), and myrtenol (11.38%; oxygenated monoterpene). The PCA of 22 selected compounds revealed differentiations of populations based on geographic distribution. The CA showed that Populations I and II from the Dinaric Alps were similar, and that Population III from the Balkan mountain system was distinct. This was the first investigation of interpopulation variability of T. baccata populations based on essential oil composition. The results of this study were compared with those of previous studies concerning volatile compounds produced by Taxus species. The results indicate that the essential oil content of T. baccata populations from this study is unique, mostly resembling the population from southeast Serbia.

Out of a total number of tree species in Serbian flora, 28% are hermaphrodites, 43% are monoecious and 29% are dioecious. The dendroflora appears to have a larger proportion of unisexual than hermaphrodite species. The monoecious system is the dominant unisexual system within the tree species in Serbia. The possible sex differentiation by RAPD markers and Correspondence Analysis was examined in a population of Fraxinus ornus var. angustifolia. On the basis of 6 selected RAPD bands which contribute to the differentiation in frequency between male and hermaphrodite individuals, Correspondence Analysis visualized the following tendency: 20 trees of each variety were separated into two groups that mainly correspond to sexual types. Our results showed that RAPD markers assisted by Correspondence Analysis could be used in identifying male and hermaphrodite individuals in F. ornus varieties.

A 5-year field survey examined western corn rootworm (WCR) (Diabrotica virgifera virgifera LeConte) beetle density in Serbia from 2002 to 2006. First-, second-, third-, fourth- and fifth-year maize fields were sampled; they represented 64.61%, 21.66%, 9.45%, 3.53% and 0.75% of all sampled fields respectively. Results showed that the mean WCR beetle population density from 794 maize fields differed depending on cropping history. Minimum mean WCR/trap/day was 0.0 in the first-year maize fields in 2002 and 2006. Maximum mean WCR/trap/day was registered in the fourth-year and the fifth-year maize fields (27.8 and 21.2 respectively). Mean population density of WCR adults increased with the number of years of continuous maize from 1.17, 4.61, 6.41, 10.30 up to 13.53 WCR/trap/day for first-fifth-year maize fields respectively. Mean WCR/trap/day ± SE exceeded the economic population threshold of >6 WCR/trap/day in third-year continuous maize fields. Out of 794 maize fields, 697 (87.78%) registered a mean population density below the 6 beetles/trap/day, a finding that predicts a risk of economic damage to a subsequent maize planting. These data are representative of the Serbian situation from 2002 to 2006; they indicate that WCR are well dispersed across commercial maize fields in Serbia. These results provide new insight into the current low WCR population densities in maize fields managed by crop rotation, a finding that can help in creating long-term management strategy.

Population dynamics of the species Plantago major L. and Poa annua L., typical representatives of ruderal vegetation, was analyzed in a replacement series experiment. The analyzed species were sown in an area with meadow vegetation, where the vegetation present had been previously removed by a total herbicide and additionally by hoeing. The objective of the experiment was to monitor growth dynamics and the effect of intra- and inter-specific interaction of the species Plantago major and Poa annua in conditions of different sowing densities and proportions. The effects of intra- and inter-specific interference and the density-dependent responses were assessed on the basis of several parameters (natality, mortality, age structure, and measures of ontogenetic changes). Based on the study results, it can be concluded that the responses of the species in the experiment were different, which is explained by different adaptive mechanisms, i.e., strategies, in the specific environmental conditions. An effect of the density dependent response was present in both species in the replacement series experiment. The response was amplified by water deficit caused by intensive evapora?tion of the bare soil. No effect of inter-specific interference was observed at the given densities of the study species on the sample plots. An effect of intra-specific interference of the species Plantago major and Poa annua was observed in the guise of a density-negative response of the rate of ontogenetic changes and fecundity.

The results of 20-year monitoring of the population of Mergus merganser in the East Dinaric Mountains are presented in this article. Colonization of the Sjenicko, Zlatarsko, and Radojina Lakes in Serbia by this species and its dispersion on the Zvornicko, Perucac, and Visegradsko Lakes in the Republic of Srpska occurred in this period. The population of goosander is progressive and we sug gest that it will expand to other lakes in the region, ones in Montenegro and the Federation of Bosnia and Herzegovina. Study Area The East Dinaric Mountains are situated in the central part of the Balkan Peninsula, with the highest peaks up to 2500 m a.s.l. The whole Dinaric region belongs to the Black Sea basin, and the Drina River catchment area includes rapid highland rivers with a great amount of water. The climate is highland continental in the area of the upper lakes, whereas sub-Mediterranean climatic elements appear in the lower canyons. Coniferous and deciduous forests with refugial habitats in the canyons make up the vegetation cover of the mountain region. The energy potential of Drina River has been greatly exploited in the past 50 years by the building of nine hydro-electric power plants with artificial lakes. The first of them, Zlatarsko Lake, was formed

Biomass accumulation, leaf longevity and growth rate of two spring forest geophytes, Scilla bifolia L. and Arum maculatum L. were estimated separately for three size groups within each population of these species. Despite the differences in leaf longevity, both species showed a similar pattern of biomass accumulation in relation to their phenologies and reproductive demands. Eco-physiological acclimation to changing light environment was assumed through photosynthetic parameters and dynamics of leaf area index in the predominant size group of each species. A light response curve was measured under natural light for each species through the continuum of its phenology to quantify the photosynthetic photon flux density at light saturation, light-saturated photosynthetic rate, light compensation point, and dark respiration. Light-saturated assimilation per leaf area basis, dark respiration rate and light compensation points were significantly higher in S. bifolia relative to A. maculatum. However, the acclimation of photosynthesis that would respond to light changes in environment was not found in S. bifolia. In contrast, in A. maculatum a marked shift in the light dependence of photosynthesis through the season was noticed, which resulted in a strong photosynthetic acclimation to the low-light conditions. Accompanied by significant leaf area index, this efficient low-light photosynthesis enabled greater leaf longevity, and consequently longer accumulative period to A. maculatum. From the different parameters that we determined (both photosynthetic acclimation and growth strategy) it would appear that these species belong to two distinct subgroups: S. bifolia to the early and A. maculatum to the late vernals. (Managing editor: Ya-Qin)

In studies of population variability, particular attention has to be paid to the selection of a representative sample. The aim of this study was to assess the size of the new representative sample on the basis of the variability of chemical content of the initial sample on the example of a whitebark pine population. Statistical analysis included the content of 19 characteristics (terpene hydrocarbons and their derivates) of the initial sample of 10 elements (trees). It was determined that the new sample should contain 20 trees so that the mean value calculated from it represents a basic set with a probability higher than 95 %. Determination of the lower limit of the representative sample size that guarantees a satisfactory reliability of generalization proved to be very important in order to achieve cost efficiency of the research. [Projekat Ministarstva nauke Republike Srbije, br. OI-173011, br. TR-37002 i br. III-43007]