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Oxidative stress in soybean seedlings and the length of the soybean stem lesions infected with the fungus Macrophomina phaseolina (Tassi) Goid were evaluated to determine the most tolerant soybean cultivar to this pathogen. The level of superoxide anion radical production, the activity of the antioxidant enzyme superoxide-dismutase (SOD), and the intensity of lipid peroxidation (LP) were measured in four soybean cultivars: Favorit, Atlas, Victoria, and Rubin. Results showed that superoxide anion radical production and SOD activity were the most elevated in the cv. Favorit inoculated with M. phaseolina, while the level of lipid peroxidation intensity was the lowest compared to the control. This indicates that the soybean cv. Favorit has managed to prevent infection with M. phaseolina. Furthermore, higher superoxide anion radical production and lower SOD enzyme activity were measured in cv. Victoria, with enhanced lipid peroxidation. This means that the cv. Victoria was infected with M. phaseolina, and was the most sensitive. None of the tested oxidative stress parameters showed a significant difference in the cvs. Atlas and Rubin compared to the control. Furthermore, the highest lesion length was measured in the cv. Victoria, followed by cv. Favorit, while the lowest lesion length was measured in cv. Atlas followed by cv. Rubin; and thus, the cv. Atlas followed by cv. Rubin, were the most tolerant soybean cultivars to this pathogen.

Brown rot (the causal agent: Monilinia laxa Aderh. and Ruhl.) is one of the most common and most destructive diseases among stone fruit, sweet cherries in particular. The objective of this paper was to determine different responses to brown rot among nine sweet cherry genotypes grown under the field conditions of infection in open field. In terms of enzyme and antioxidant activity occurring under infection, the studied genotypes showed significant differences in comparison with healthy fruits. However, at the biochemical level, soluble proteins (SP), superoxid dismutase activity (SOD), guaiacol peroxidase activity (GPX), pyrogallol peroxidase activity (PPX), lipid peroxidation (LP) and antioxidant activity (ABTS and TRC assays) in sweet cherry fruits was significantly affected by genotype, plant disease and interaction of these two factors. Significant differences between studied parameters of healthy and infected fruits were recorded in genotypes Junska rana, Merchant, Sue and III/VAL. The parameters studied can be used as a method of assessment of resistance to brown rot among sweet cherry cultivars. Mrka trulež (uzročnik: Monilinia laxa Aderh. i Ruhl.) je jedna od najčešćih i najdestruktivnijih bolesti koštičavih voćaka, naročito trešnje. Cilj ovog rada je bio da se utvrde različiti odgovori na mrku trulež ploda između devet genotipova trešnje, uzgajanih u uslovima prirodne infekcije na otvorenom polju. U pogledu enzimatske i antioksidativne aktivnosti koja se javila u uslovima infekcije, ispitivani genotipovi su pokazali značajne razlike u odnosu na zdrave plodove. Na razlike u biohemijskom pogledu uticali su: genotip, prisustvo biljne bolesti kao i interakcija ova dva faktora. Biohemijski parametri koji su pokazali razlike u uslovima infekcije su: sadržaj rastvorljivih proteina (SP), aktivnost supereksid dismutaze (SOD), aktivnost gvajakol peroksidaze (GPX), aktivnost pirogalol peroksidaze (PPX), lipidna peroksidacija (LP) i antioksidativna aktivnost (ABTS i TRC testovi). Značajne razlike između ispitivanih parametara zdravih i zaraženih plodova zabeležene su u genotipovima Junska rana, Merchant, Sue i III/VAL. Ispitani parametri se mogu koristiti kao metoda procene otpornosti na mrku trulež izmedju genotipova trešnje.

Changes in enzymatic and non-enzymatic antioxidant systems in soybean (cv. Becejka) and maize (hybrid NS 640) seedlings were studied after inoculation with Rhizoctonia solani AG 2-2 IIIB. Enzymes such as plant peroxidases and phenylalanine ammonia-lyase were induced in the analyzed organs of both plant species. Nevertheless, increase in superoxide dismutase activity was recorded only in infected maize roots. After inoculation, lipid peroxidation was enhanced only in soybean plants. Seedlings showed ability to accumulate phenolic compounds, some of which correlated with disease intensity. A significant decrease in total carotenoid amounts was recorded in infected soybean and maize plants. After R. solani infection, the enzymatic and nonenzymatic antioxidant systems were more efficient in maize than in soybean seedlings.

Resistance of F1, F2, and BC1 generations from crosses between cultivated sunflower inbreds with different tolerance towards Sclerotinia, as well as the inbred lines themselves to different forms and methods of infection with Sclerotinia in order to find out the genotypes of interest for breeding was tested. All tested genotypes showed a high level of tolerance toward artificial root inoculation with sclerotia, where three out of five tested hybrids were more resistant than their respective mother line. All tested genotypes, except for PR-ST-3A, were more susceptible to stem inoculation with sclerotia than stem infection with mycelium. All hybrids and all progeny from back crosses with the mother line were more resistant to stem infection with mycelium than parental lines, and progeny from back crosses was more resistant than or equally resistant as hybrids. In artificial inoculation of heads with mycelium and sclerotia, some tested genotypes were more susceptible to mycelium test, while others were more susceptible to sclerotia lest. There was no regularity in susceptibility of hybrids to sclerotia test regarding parental lines. All hybrids, except for Ha-48A x RUS-RF-OL-168, were significantly more susceptible to sclerotia test on stem than both parents. Hybrid Ha-48A x RUS-RF-OL-168 had the similar level of resistance as better parent. Ispitivana je otpornost F1, F2, i BC1 generacija nastalih ukrštanjem inbred linija gajenog suncokreta različite tolerantnosti prema Sclerotinia, kao i samih inbred linija na različite forme i metode infekcije sa Sclerotinia u cilju pronalaženja genotipova interesantnih za proces oplemenjivanja. Svi ispitivani genotipovi su pokazali visok stepen tolerancije prema veštačkoj zarazi korena sklerocijama, pri čemu je tri od pet testiranih hibrida bilo otpornije od linije majke. Svi ispitivani genotipovi, osim PR-ST-3A, su bili osetljiviji na veštačko zaražavanje stabla sklerocijama u odnosu na veštačku inokulaciju micelijom. Svi hibridi kao i svo potomstvo iz povratnih ukrštanja sa linijom majke su bili otporniji na veštačku inokulaciju stabla micelijom od roditelja, s tim što je potomstvo iz tih povratnih ukrštanja bilo otpornije ili u nivou sa hibridima. Prilikom veštačke inokulacije glava micelijom i sklerocijama, pojedini ispitivani genotipovi su bili osetljiviji na metod veštačke inokulacije sa micelijom, dok su drugi bili osetljiviji na veštaču zarazu sklerocijama. Nije uočena pravilnost u osetljivosti hibrida na veštačku zarazu sklerocijama u odnosu na roditeljske komponente. Svi hibridi osim Ha-48A x RUS-RF-OL-168, su bili značajno osetljiviji na test sklerocijom na stablu od oba roditelja. Hibrid Ha-48Ax RUS-RF-OL-168 je bio u nivou boljeg roditelja.

The effect of exogenously applied auxins on oxidative stress was studied in six rootstock selections of Prunus cerasus, P. mahaleb and P. fruticosa aiming at the effect of phytohormones on the level of the lipid peroxidation (LP). Standard rootstock PHL-A was used as a control. Leaves were collected on 0, 1st, 3rd and 7th day of inserting cuttings into the rooting substrate. Auxin mixture consisted of 0.8% α-naphthylacetic acid and 0.5% indolebutyric acid. Differences in intensity of the LP between auxin-treated and -untreated cuttings were examined. Almost all of investigated selections had lower LP intensity after auxin application (11.4-47.2%). The most prominent change was in leaves of PHL-A (49.2%). LP-lowering effect were recorded in leaves of P. fruticosa (56.9%) on 7th day and in P. mahaleb on 1st and 3rd day (5.9, 5.8%). Intensity of LP could be used as one of the biochemical parameters in further rootstock selection and production.