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.
There are only ambiguous data in literature that suggest the presence of Galanthus gracilis Celak. in the flora of Serbia. Throughout its range G. gracilis is often confused with closely related species G. elwesii Hook., with which it shares several morphological characteristics, and in some cases the same name is erroneously used for both species (G. graecus Orph.). Only about a decade ago, the genus was a subject of taxonomic revision by the English author Aaron P. Davis, whose work eliminated confusion created by the previous conflicting divisions. Therefore, further studies are required to determine the exact distribution of this species. In this paper, we officially report the presence of G. gracilis in Serbia, with a description of its habitat and estimation of the threatened status.
As a contribution to the study of the melliferous flora of Serbia, nectar production in two species of the genus Galanthus L. (G. nivalis L., and G. elwesii Hook.) was investigated. The intensity of nectar secretion was determined directly, using the microcapillary method. The study included determination of the total daily nectar amount per flower, and an analysis of nectar secretion dynamics during the day and during the flower ontogeny. The results show that the total daily amount of nectar per flower is low, and flowers of both species exude nectar only once during the day and during the flower ontogeny. However, despite the low nectar production, Galanthus species represent a first valuable source of nectar and pollen to pollinators in the early spring period, when only a small number of species are in the flowering phenophase.
This paper presents research results on forest decline in Serbia. The results were obtained through monitoring defoliation of 34 tree species at 130 sample plots during the period from 2004 to 2018. This research aimed to determine whether the occurrence of defoliation and tree mortality were caused by drought. Defoliation was assessed in 5% steps according to the International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) methodology. All the trees recorded as dead were singled out, and annual mortality rates were calculated. To determine changes in air temperature and precipitation regimes during the study period, we processed and analysed climatic data related to air temperature and precipitation throughout the year and in the growing season at 28 main weather stations in Serbia. Tree mortality patterns were established by classifying trees into three groups. The first group of trees exhibited a gradual increase in defoliation during the last few years of monitoring, with dying as the final outcome. The second group was characterised by sudden death of trees. The third group of trees reached a higher degree of defoliation immediately after the first monitoring year, and the trees died after several years. Tree mortality rates were compared between years using the Standardised Precipitation Evaporation Index (SPI) and the Standardised Precipitation Evapotranspiration Index (SPEI), the most common methods used to monitor drought. The most intensive forest decline was recorded during the period from 2013 to 2016, when the largest percentage of the total number of all trees died. According to the annual mortality rates calculated for the three observation periods (2004–2008, 2009–2013, and 2014–2018) the highest forest decline rate was recorded in the period from 2014 to 2018, with no statistically significant difference between broadleaved and coniferous tree species. As the sample of coniferous species was small, the number of sample plots should be increased in order to achieve better systematic forest condition monitoring in Serbia. The analysis of the relationship between defoliation and climatic parameters proved the correlation between them. It was noted that the forest decline in Serbia was preceded by an extremely dry period with high temperatures from 2011 to 2013, supporting the hypothesis that it was caused by drought. We therefore conclude that these unfavourable climatic conditions had serious and long-term consequences on forest ecosystems in Serbia.
The paper presents phytosociological characteristics of the sessile oak and hornbeam community (Querco petraeae-Carpinetum betuli Rudski 1949. s.l.) in the area of Kosmaj. Phytosociological relevés of the investigated association were taken at altitudes ranging from 339 to 410 m, with Eastern to northeastern aspects, and the slope of 15-23°. The community occurs on deeply ilimerized soils - luvisols over flysch. The floristic composition of this phytosociological community is diverse, including plants from thermophilicmand mesothermal oak forests and some plants from beech forests. With regard to the spectrum of range types, the investigated community Querco petraeae-Carpinetum betuli Rudski 1949. s.l. has a Central European range of distribution. Regarding the bioloigical spectrum of life forms, most species are considered phanerophytes and hemicryptophytes, with an increased share of geophytes.
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