No abstract

Извод: Дуглaзиja je jeднa oд нajчешће гајених врстa чeтинaрa у плaнтажaмa и шумским културама у више замаља Европе. Moдeл прoвeниjeничнoг тeстa зaснивa се нa aнaлизaмa свojстaвa дуглaзиje (рaстa и aнaтoмских, физиoлoшких, хeмиjских, мeхaничких, као и других особина) с циљем прoвeрe oпрaвдaнoсти трaнсфeрa сeмeнa из Сeвeрнe Aмeрикe у eкoсистeмe Србиje. Овакав прoгрaм сe спрoвoди у Србиjи нa вишe лoкaциja сa дуглaзиjoм рaзличитих прoвeниjeнциja. Како је анализа различитих физиолошких својстава стабала од значаја при интродукцији одређених провенијенција на станишта у Србији, у овом рaду су истрaживaнe вaриjaбилнoсти сaдржaja кaлиjумa у младим чeтинaмa дуглaзиje рaзличитих прoвeниjeнциja на eкспeримeнтaлном пољу у Србиjи. Значај калијума у физиолошким процесима биљака је веома велики. Калијум је есенцијални елемент који учествује у низу биохемијских и физиолошких процеса и има значајну улогу при адаптацији биљака у условима биотичког и абиотичког стреса. Највећи садржај калијума утврђен је код провенијенције "Орегон 205-14", што је једина провенијенција код које садржај калијума статистички значајно одступа од просека, те се она може окарактерисати као супериорна за усвајање и акумулацију овог елемента. Констатовано је да, у овој фази, разлике у концентрацији калијума код стабала у провенијеничном тесту немају значајног утицаја на параметре раста. Даља истраживања треба да укажу на то да ли садржај овог биогеног елемента има утицај на нека друга својства значајна за oдaбир прoвeниjeнциja у прoцeсу интрoдукциje, као што је отпорност на стресне факторе.

The selection of tree species can affect the success of afforestation in the rehabilitation of degraded forest sites and forest restoration. In general, black locust (Robinia pseudoacacia L.) and black pine (Pinus nigra Arnold.) represent the most commonly used species in the afforestation of soils that have been degraded by erosion. As far as the extent of the ameliorative effects of black locust and black pine are concerned, it was found that they may play an important role in the selection of species for the afforestation of extremely degraded sites. This study is aimed at determining the potential of black locust and black pine to affect several soil properties, erosion control and C stock, thus creating favourable site conditions for the restoration of previous forest vegetation. This research was conducted in the Grdelica Gorge in south east Serbia, where eight sample plots with an average size of 0.47 ha were established 60 years ago on terrain afforested with black locust and black pine. In each sample plot, we measured the diameter at breast height of all black locust and black pine trees, and the height of 10 black locust and 10 black pine trees in each diameter class. In addition, samples of mineral soil (from depths of 0-5, 5-10 and 10-20 cm) were taken at 4 randomly selected soil profiles in each sample plot, and 8 samples of litter (30 × 30 cm) were also collected. Additionally, laboratory analyses of the physical and chemical properties of the soil and litter were performed in 2 replicates. The obtained results showed that: (1) at the 0-5 cm depth, there was no statistically significant difference in the reaction of the soil solution, although a significant difference in the reaction of the soil solution between the soils under the two species was observed at soil depths greater than 5 cm; (2) there was a significantly higher N content under black locust in the 0-5 cm soil layer; (3) the reduction of soil loss under black locust is statistically significant in all observation periods; (4) black pine is more efficient in C storage. Our results demonstrate that black locust has the potential to improve soil properties and reduce soil loss caused by erosion, while its favourable impact does not decrease over time, making it more suitable for afforestation on degraded land in the examined area.

The aim of this paper was to examine how the heavy metals cadmium (Cd) and lead (Pb) influence the germination and early growth of seedlings of the fast-growing tree species Ulmus pumila L. Seeds were germinated and seedlings were hydroponically grown in a solution with Cd-nitrate and Pb-nitrate at concentrations of 20 ?M, 50 ?M and 90 ?M. Our results show that seeds can germinate in the presence of these two heavy metals at all of the applied concentrations with no significant reduction in qualitative (germination capacity, germination energy) or quantitative (germination intensity, mean germination period) germination parameters as compared to the controls. Early seedling development was also possible at higher concentrations of both heavy metals. Cd reduced hypocotyl length, but not significantly the length of radicles. Pb did not influence hypocotyl length and stimulated radicle length significantly (95%). These results could mark a step forward in defining the tolerance of U. pumila to the presence of Cd and Pb, and to the possibility of using this fast-growing tree which is resistant to different abiotic and biotic stresses, for phytoremediation or soil reclamation purposes. [Projekat Ministarstva nauke Republike Srbije, br. 43007]

Amorpha fruticosa is in many countries, and also in Serbia, one of the most dangerous invasive species. The detection of mechanisms which inhibit the spreading of Amorpha population would be of great significance for finding the adequate measures of biological control. In this sense, first of all it is necessary, inter alia, to determine Amorpha ecological and coenological characteristics. The vegetation studies of wet sites in Belgrade were compared. The study results indicate that Amorpha is present in forest communities, from the lowest elevations at the timber line to the highest elevations, where the periods of underground and flood waters are the shortest, or where they are absent. Amorpha forms thick brushland on meadows with different water regimes and in forest plantations of different canopy closure. If it is regularly removed by felling, Amorpha does not endanger the structure and the floristic diversity of meadow communities. Amorpha is absent or rare in forest plantations of the densest canopy, as well as in the communities which belong, or once belonged, to the alliance Magnocaricion Br.-Bl