Plants can be very useful as soil guards, and as an additional source of vitamins and minerals in human nutrition. Some, of them also have medicinal properties. Portulaca oleracea L. contains more antioxidants than spinach. It is also rich in vitamins C and B, including riboflavin, pyridoxine,niacin, carotenoids and traces of minerals such as iron, magnesium and calcium. The following analyses were carried out: determination of moisture in the plant material, preparation of macerates, extraction of samples in the Soxhlet apparatus, ultrasonic extraction of samples, determination of extract density by an aerometer, determination of extraction yield by maceration, determination of extraction yield by Soxhlet extraction, determination of extraction yield by ultrasonic extraction and determination of the content of vitamin C in the extracts obtained. The dry matter content obtained on the basis of three measurements was 7.679% and the moisture content was 92.321%. The smallest extraction yield was obtained by Soxhlet extraction 0.1625 g, followed by maceration 0.3575 g and ultrasonic extraction 0.775 g. The highest density was determined for the ultrasonic extract 0.85 g / cm³, and the smallest for the Soxhlet´s extract 0.70 g / cm³, which was correlated with extraction yields. The content of vitamin C was highest in the ultrasonic extract 15.5 mg / 100 g, slightly lower in the macerate extract 6.5 mg / 100 g, and the smallest in the Soxhlet´s extract 2.5 mg / 100 g. The content of bioactive components in purslane leaf depends on the extraction method.

Extracts were subjected to the following analyses: determination of total phenols, total flavonoids and anthocyanins, and refractometric determination of soluble solids. The results showed that the content of flavonoids was 0.4710 mg/ml in Urtica dioicа extract, 0.3950 mg/ml in Equisetum arvense extract, 0.2997 mg/ml in Thymus serpyllum extract and 0.1556 mg/ml in Achillea millefolium extract. The highest content of phenolic compounds was found in Thymus serpyllum extract (2.3583 mg/ml), followed by Equisetum arvense (2.2724 mg/ml) and Urtica dioicа extract (2.1374 mg/ml), and the lowest in Achillea millefolium (1.8061 mg/ml). The content of anthocyanins was highest in Urtica dioicа extract (3.966mg/l), followed by Thymus serpyllum (3.715mg/l) and Equisetum arvense (3.549mg/l) extracts, and lowest in Achillea millefolium extract (0.0835mg/l). The soluble solids content was highest in Urtica dioicа and Equisetum arvense (2 BRIX% at 20 o C), followed by Thymus serpyllum (1.5 BRIX% at 20 o C), and lowest in Achillea millefolium (1 BRIX% at 20 o C). The results showed that extracts obtained by maceration contained bioactive components; this study, therefore, provides a basis for further and deeper research on the use of these extracts as potential biostimulators in organic agriculture.

It is generally accepted belief that serpentine areas are inhabited by a smaller number of species than known from other types of geological substrates. Based on this idea we selected, as a model system, the area of the northwestern Serbia and Šumadija with well represented serpentinite, carbonate and silicate rocks, in order to evaluate the influence of a different geology and habitat types on the differentiation of the analyzed floras and determine whether the serpentinites are really inhabited by a smaller number of species than other types of geological substrate. Based on the results of several statistical analyses of the investigated area, we found that: i) serpentinites are inhabited by a smaller number of species compared to carbonate, but a higher number of species compared to silicate geological substrate, ii) the particular habitat types on serpentinites exhibit greater floristic diversity than the equivalent habitat types on other geological substrates, iii) similarity within the same habitat type of serpentinite, carbonate and silicate floras is greater than the similarity between the different serpentine floras of the different habitat types, iv) environmental factors such as moisture and habitat type have a larger impact on the differentiation of the flora, compared to the type of geological substrate, and v) the largest number of serpentinophytes were registered in the xerophilous forests and xerophilous grasslands compared to other habitat types.

This study aimed to determine the concentrations of ten metals (Mn, Ni, Ca, Mg, Fe, Zn, Cr, Pb, Cd, Cu) in the soil at depths of 10 and 20 cm and selected plant species (Populus nigra L., Fraxinus ornus L., Salix alba L., Salix caprea L.), as well as to assess the ability of these plants of metal bioaccumulation, translocation and phytoremediation on the location of the mine pit and flotation tailings of the selected mine (in the center of the Republic of Serbia). The concentrations of Pb and Cu in the investigated soil at a depth of 10 cm were above remediation values stated in the regulations of the Republic of Serbia. At the same time, the concentration of Cd, Cr, Pb and Cu was above the limit values in both of the examined soil depths, while Ni in the soil at a depth of 10 cm was above the limit value determined in the Directives of the European Union. The species F. ornus shows the ability to phytoextract Ca, species P. nigra Zn, Ca and Cd, while both Salix species have the capacity to phytoextract Zn and Ca. The results showed that species S. alba is an efficient bioaccumulator of Mn, Fe, Cr, Pb, Zn and Ca, S. caprea of Fe, Cu, Cr, Mg and Pb, and P. nigra of Mn and Cd. The bioaccumulation and translocation of the investigated elements depend on plant species and their organ. The selection of plant species adequate for remediation should take this into account.

One of the major problems confronting agricultural production is heavy metal contamination of agricultural soils, which imposes considerable limitations on productivity and leads to great consumer health and safety concerns about the products obtained on these soils.The objective of this study was to evaluate heavy metal dynamics in the soil-leaf-fruit system in an intensive apple cv. 'Idared' planting located in the Municipality of Goražde. Heavy metal contents in the soil samples and plant material were determined by atomic absorption spectrophotometry using a Shimadzu 7000 AA device, according to the instructions specified in the ISO 11047 method. The dynamics of the heavy metals analysed, excepting zinc, in the soil-leaf-fruit system was characterised by relatively high total levels of heavy metals in the soil and a very low degree of their accumulation in the leaves and in particular the fruits. No fruit sample was found to have toxic levels of any of the heavy metals analysed. In terms of soil contamination, this suggests the suitability of the study location for safe apple fruit production.