Secondary plant biomolecules are the main agents in biochemical inter?actions between plants and the environment. It is possible to distinguish the role of secondary biomolecules in allelopathic (plant-plant) activity, plant-insect, plant-microbe, plant-herbivore and others. These interactions can significantly affect the productivity of agricultural crops. Application of allelochemicals into agricultural practice may reduce the use of herbicides. Effect of Salvia sclarea L. and Clinopodium menthifolium (Host) aqueous extracts on lipid peroxidation process, as well as the activity of antioxidant enzymes in leaves and roots of Jimson weed (Datura stramonium L.) and soybean (Glycine max L.) seedlings were examined 24 h, 72 h and 120 h after the treatment. The third aim was to evaluate effectiveness of aqueous extract as contact toxicant against Rhyzopertha dominica. Our results showed that S. sclarea aqueous extract induced lipid peroxidation in roots of Jimson weed seedlings 24 h after the treatment. Furthermore, both tested concentrations of C. menthifolium aqueous extract induced lipid peroxidation in Jimson weed roots 72 h and 120 h after the treatment. It was observed that S. sclarea aqueous extract showed toxic effect against R. dominica, with high mortality rate (above 95%).

This study was conducted in order to assess the effect of inoculation of soybean (Glycine max L.) seeds with Trichoderma asperellum, followed by mites (Tetra nychus 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. as perellum 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 non-inoculated 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.

AN TI O XI DANT PO TEN TIAL OF Cli no po di um ment hi fo li um, Sa tu re ja mon ta na AND Sal via Scla rea (La mi a ce ae) EX TRACTS AB STRACT: Plants which be long to La mi a ce ae fa mily are good po ten tial so ur ces of na tu ral an ti o xi dants use ful for pre ven ting oxi da ti ve stress-re la ted di se a ses. The food in du stry is be co ming in cre a singly in te re sted in aro ma tic herbs, in clu ding plants from La mi a ce ae fa mily, be ca u se of the ir an ti-in f lam ma tory pro per ti es and an ti o xi dant ac ti vi ti es, due to growing con su mer de mands for he althy fo ods of na tu ral ori gin. In the pre sent in ve sti ga tion, the com pa ra ti ve an ti o xi dant po ten tial of aqu e o us and ace to ne ex tracts of three La mi a ce ae speci es are de scri bed: Cli no po di um ment hi fo li um (Host), Sa tu re ja mon ta na L., and Sal via scla rea L., using three met hods: 2,2-azi no bis (3-ethyl-ben zot hi a zo li ne-6-sul fo nic acid) ra di cal (ABTS) sca ven ging, 1,1-Dip henyl-2-pi crylh ydrazyl ra di cal (DPPH) sca ven ging, and fer ric re du cing an ti o xi dant po wer (FRAP) as say and the ir cor re la ti ons with to tal pheno lic and f la vo noid con tents. An ti o xi dant ca pa city sho wed a po si ti ve re la ti on ship com pa ring three abo ve men ti o ned tests. An ti o xi dant ca pa city de tec ted by an ti o xi dant ABTS, DPPH, and FRAP as says was po si ti vely co r re la ted with to tal phe no lics con tent. Aqu e o us ex tract of C. ment hi fo li um sho wed gre a ter an ti o xi dant po ten tial. KEYWORDS: ABTS as say, Cli no po di um ment hi fo li um (Host), DPPH as say, FRAP va lue, Sal via scla rea L., Sa tu re ja mon ta na L.