Zoran Galić

Antioxidant characterization of oak extracts combining spectrophotometric assays and chemometrics.

Antioxidant characteristics of leaves, twigs, and acorns from two Serbian oak species Quercus robur L. and Quercus petraea L. from Vojvodina province (northern Serbia) were investigated. 80% ethanol (in water) extracts were used for antiradical power (ARP) determinations against DPPH•, •NO, and O2 •− radicals, ferric reducing antioxidant power (FRAP), total phenol, tannin, flavonoid, and proanthocyanidin contents. Permanganate reducing antioxidant capacity (PRAC) was determined using water extracts. Beside, mentioned parameters, soluble proteins, lipid peroxidation (LP), pigments and proline contents were also determined. The data of different procedures were compared and analyzed by multivariate techniques (correlation matrix calculation and principal component analysis (PCA)). PCA found that investigated organs of two different oak tree species possess similar antioxidant characteristics. The superior antioxidant characteristics showed oak leaves over twigs and acorns and seem to be promising source of antioxidants with possible use in industry and pharmacy.

Provenance plasticity of European beech leaf traits under differing environmental conditions at two Serbian common garden sites

Climate change will affect European beech (Fagus sylvatica L.) ecosystems negatively due to well-known vulnerability of this species to drought. Phenotypic plasticity has been recognized as the primary means in rapid acclimation to adverse environmental conditions. Provenance trials of forest tree species represent a valuable tool for assessing provenance adaptive potential to changing environments. In the present study, we examined the adaptive response capability (plasticity) of certain leaf anatomical traits in different European beech provenances to contrasting environmental conditions prevailing in two provenance trials. While one location of the trials is an isolated, marginal site, the other is a site within the original geographic range of beech forests in Serbia. The study involved 12 provenances originating from Austria, Bosnia and Herzegovina, Croatia, Germany, Hungary, Romania and Serbia. The results of the study evidenced that genetic differences of the provenances are mainly responsible for the differences in leaf traits. Cluster analysis showed absence of association between provenances from the same geographic regions (e.g., Germany and Balkan Peninsula, respectively), revealing phenotypic heterogeneity between them. Steep reaction norms, observed for anatomical traits studied, indicate the possibility of plastic provenance response to changes in environmental conditions. The highest values of plasticity index, observed for stomatal density and thicknesses of palisade and spongy parenchyma, seem to be the result of a regulative function of stomata and mesophyll structure on physiological adaptation to the unfavorable growth conditions at the marginal site. Such sclerophyllous leaf structures, indicating drought resistance, were observed in certain provenances from Central/Eastern Europe and mesic sites, indicating that beech provenances from warmer sites in Southern Europe may not necessarily be the only source of drought-resistant ecotypes.

Application of pre-emergence herbicides in poplar nursery production

In addition to pests and diseases, weeds are a major problem in poplar nursery production. The possibilities of herbicide application in juvenile poplar growth were researched, taking into account that weeds are one of the main limiting factors. The following pre-emergence herbicides were tested: acetochlor, S-metolachlor, metribuzin, oxifluorfen, and dimethenamid during two vegetation seasons at two locations, which differed by the soil physico-chemical characteristics. The study results show that the number of weeds on sample plots was significantly reduced by the tested herbicides when compared to control plots. The highest reduction in the number of weeds was achieved using the herbicides acetochlor and metribuzin. However, metribuzin showed a phytotoxic effect on sandy soil. Metribuzin application is recommended only on the soils with higher contents of organic matter, where the phytotoxic effect was absent. Acetochlor, S-metolachlor, oxifluorfen, and dimethenamid were not phytotoxic to poplars and can be used for weed suppression in the production of poplar plants.

Soil pro pert ies in sessile oak fore sts (Quercetum montanum typicum Čer. et Jov. 1953) in the are a of Fruška Gora

The soils formed on sandstones in sessile oak forests (Quercetum montanum typicum Cer. et Jov. 1953) were researched in the area of Fruska Gora. On permanent sample plots established in management units “Cortanovacka Forest-Hopovo-Velika Remeta“ and “Beocin-Manastir-Katanske Livade-Osovlje“, in the are of NP “Fruska Gora“, aiming at the monitoring of the effect of light regime on the development of sessile oak progeny in the given environmental conditions, based on the morphogenetic characteristics of the soil and analytic values of the soil properties, and based on the soil classification by Skoric et al. (1985), the following two soil types were defined: acid brown soil (dystric cambisol), and illimerised soil (luvisol). Acid brown soil belongs to the form of medium deep soils, and illimerised soil is classified as deep soil.

Ecological characteristics and the remediation potentials of opencast mines at Celarevo and Sajkas brickyards, Vojvodina, Serbia

Introduction In the Vojvodina province, Northern Serbia, the consequences of soil degradation, damage and devastation are increasingly explicit. The negative processes lead to a significant decrease of the area of farmland, forest and various forms of protected natural parks. An especially endangered soil type is chernozem, the highly productive agricultural soil which occupies approximately 45% of the area of Vojvodina (Živković et al., 1972). The impacts of different processes of degradation, damage, and finally the devastation of the most productive soils are multiple. Unfortunately, the consequences of the adverse effects cannot always be adequately mitigated, i.e. eliminated. One of the most frequent way of soil degradation in Vojvodina is raw material exploitation in many brickyards (Miljković et al., 2001). In this way, in addition to soil damage, a thick layer of parent matherial on which the soil was originally formed, is permanently lost. Raw material exploitation causes the changes of the relief, hydrological, ecological and site conditions in general. The spontaneous soil renewal in the opencast mines of brickyards is a slow process which results in soil formation with the significantly poorer productive properties. Therefore, such areas should be subjected to the adequate rehabilitation procedures. This study presents the complex analyses of the present environmental status and proposes the sustainable rehabilitation methods of the birckyard opencast mines at Čelarevo and Šajkaš.

Dense poplar plantations as the raw material for the production of energy

The higher heating value of wood and bark was determined for several poplar (Populus spp) clones. The study included the juvenile one year old plants of the following clones: P.×euramericana cl. ostia, P. nigra cl.53/86, P. deltoides cl. PE 19/66, P.×euramericana cl. I-214, P. deltoides cl. S6-7 and P.×euramericana cv. robusta. By using FVI which takes into account ash content, wood bulk density, and moisture content, it was determined that poplar wood can be a significant energy raw material, primarily thanks to its short rotation cycle and a very high wood volume increment. Significant differences were determined in the values of wood basic density which affect the higher heating value of the study poplar clones, and consequently the yield (weight) of biomass produced per unit area of dense plantations. This is reflected also on the estimated amount of energy that can be produced by the combustion of biomass of the whole one year old plants.