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The current investigation aimed to present an overview of the conservation of biological diversity of rare and endangered plant species. Methods of biodiversity conservation as well as several overview recommendations for the preservation of various rare species have been considered. An overview of the taxa included in the red book has been presented on the example of the Russian Federation. Global and local codes and classifiers of plant rarity were also presented. Future prospects for the conservation of biological diversity and the creation and development of bioresource collections have been considered.

Distribution and level of 16 individual and total polycyclic aromatic hydrocarbons (∑PAHs) were assessed in soils, roots and above-ground tissues of reed (Phragmites australis) on monitoring plots in the city of Kamensk-Shakhtinskyi (Southern Russia, Rostov Region). The total concentration of the 16 PAHs in soil samples ranged between 499.0 to 7177.9 µg kg -1 . Samples from the plot no. 4 had the highest PAHs concentrations of 7177.9 µg kg -1 . The mean concentration of ∑16PAHs in plot no. 3 was noticeably higher than those in other monitoring sites for both root (363.0 µg kg -1 ) and above-ground tissues (239.8 µg kg -1 ). The distribution of PAHs ring size was in the order of 5-6˃4˃3˃2 in soil samples and HMW PAHs fractions represent 57.3% of the total PAHs. The concentrations of 3-4 ring PAHs were higher than HMW PAHs with 5-6 aromatic rings in all P. australis tissues. Diagnostic ratios of PAHs indicated that anthropogenic activities were probably major sources of PAHs. Accordingly, the maximum accumulation was found for phenanthrene among the 16 priority PAHs in the most of the soil and plants samples. More PAHs were accumulated in roots, as reflected by its higher mean concentration of PAHs in each plot. In addition, the BCF and TF values of LMW PAHs with 2-and 3-rings were higher than those of HMW PAHs. Taken together, our results indicated that there were an intensive accumulation of PAHs in the zone of industrial sewage tanks and sludge reservoirs as well as an obvious translocations of PAHs from the polluted soils to plant tissues, therefore, more attention is required to be paid to the PAH contamination in this area.

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<p>Polycyclic aromatic hydrocarbons are a group of organic pollutants influencing different aspects of plants physiology. Physiological responses associated with the impact of phenanthrene (500, 1000, 1500, 2000 ppm) were analysed on Panicum miliaceum L. Seed germination was delayed in all treatments and 2000 ppm of phenanthrene (PHE) significantly retarded the germination rate (28 %) compared to control. The results revealed after 30 day of cultivation, only 1500 and 2000 ppm of PHE had negative impacts on growth parameters as well as photosynthetic pigment contents. Plants exposed to 500 and 1000 ppm of PHE showed an increase in the growth parameters without any symptoms of toxicity, indicating the high tolerance of seedlings to PHE. The activities of antioxidant enzymes were elevated in treated plants. In higher concentrations, H2O2 content also increased despite a reduction in malondialdehyde content. Furthermore, PHE had no effect on root phenol and shoot flavonoid contents and on shoot and root protein contents. Taken together, only higher concentrations of PHE triggered oxidative stress. It can be concluded PHE was not very toxic to P. miliaceum probably because of higher activity of antioxidant system involving in elimination of produced ROS even in plants treated by PHE higher concentrations.</p>