Antioxidant potential of ragweeds: Ambrosia artemisiifolia, A. trifida and Iva xanthifolia

The combination of reproductive success with high stress tolerance (through osmotic adjustment and antioxidants) is essential for invasion success, particularly in stressful environments in the frame of global change.Antioxidant capacity could be a possible marker of adaptation to variable environmental conditions, since change in amount of antioxidants represents one of the first responses to various environmental stimuli. Among investigated ragweeds, I. xanthifolia leaves had more pronounced guaiacol-peroxidase (GPx) activity (2.5- to 9.7-fold) than A. artemisiifolia and A. trifida. A. artemisiifolia and I. xanthifolia leaves have similar reduced glutathione (GSH) content (13.05 μmol g-1 fr. w.), while A. trifida had 1.3-fold lower GSH concentration. However, superoxide-dismutase (SOD) activity was invariable in all investigated plants (234.1-247.5 U g-1 fr. w.). The highest content of total phenolics, tannins, flavonoids and proanthocyanidins were detected in A. trifida leaves (up to 3.7-fold the amount of the others). According to antioxidant activity (O2˙-, ˙OH and DPPH-scavenging tests), investigated ragweed species could be presented in a scale: A. trifida > I. xanthifolia > A. artemisiifolia. Accumulation of non-enzymatic antioxidants and lower content of GSH point to different oxidative stress avoidance strategies of A. trifida when compared to A. artemisiifolia and I. xanthifolia within the same environmental conditions

Mineral composition of selected Salvia species growing wild in the Vojvodina Province

Composition of mineral elements has been investigated in three Salvia species (Lumiaceae) growing wild in the Vojvodina Province (Serbia), as well as in a commercial phytopreparation (tea) of Salvia officinalis L. We determined concentrations of micro- and macroelements in dried plant material in order to evaluate their nutritive and medicinal value and to indicate an easily accessible natural source that could be used as a possible food supplement. The study showed that the plants were well supplied with essential elements. Concentrations of potentially harmful heavy metals (Pb, Cd, Ni, Cr) were below their respective toxic levels. From the nutritive and medicinal aspects, the investigated Salvia species may be considered as a natural source of essential microelements, especially Fe and Cu, with a low capacity for heavy metal accumulation

Antioxidant properties of soybean seedlings inoculated with Trichoderma asperellum

This study was conducted in order to assess the effect of inoculation of soybean (Glycine max L.) seeds with Trichoderma asperellum, followed by mites (Tetranychus urticae) exposure on lipid peroxidation (LP) process and the activity of antioxidant enzymes. T. urticae is an occasional pest of soybean that causes biotic stress. Biotic stress leads to overproduction of reactive oxygen species (ROS) which may cause damage to vital biomolecules. Enzymatic antioxidant defense systems protect plants against oxidative stress. T. asperellum is commonly used as biocontrol agent against plant pathogens. It has been suggested that previous inoculation of seeds with T. asperellum may cause induced resistance against biotic stress. The aim of this study was to determine LP intensity and antioxidant enzymes activity in inoculated and non-inoculated soybean seedlings with and without exposure to mites. Noticeably higher LP intensity was detected in non-inoculated group treated with mites compared to control group. Inoculated soybean seedlings treated with mites had lower LP intensity compared to noninoculated group. Also, it has been noticed that inoculation with Trichoderma asperellum itself, produced mild stress in plants. In addition, positive correlation between enzymes activity and LP was noticed. The level of oxidative stress in plants was followed by the change of LP intensity. According to results obtained, it was concluded that the greatest oxidative stress occurred in non-inoculated group treated with mites and that inoculation successfully reduced oxidative stress. The results indicate that inoculation of soybean seeds with T. asperellum improves resistance of soybean seedlings against mites attack. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR-31022