Nevena Mihailović

Chlorophyll Metabolism in Leaves of Higher Poikilohydric Plants Ramonda serbica Panč, and Ramonda nathaliae Panč, et Petrov. during Dehydration and Rehydration

Summary Ramonda serbica and R. nathaliae (Gesneriaceae) are endemo-relic species of the Balkan peninsula and the desiccation-tolerant homoiochlorophyllous flowering plants. In order to follow the pattern of chlorophyll metabolism during dehydration and after rewatering, the chlorophyll content was studied. Its change during the dehydration was monitored in intact plants and during the recovery in intact specimens as well as in cut off leaves. The regreening rate depended on previous hydration state of plants collected from their natural habitat. Eight to 12 h after the start of the rehydration of air-dried detached leaves the resynthesis of chlorophyll began. Rehydration and chlorophyll resynthesis were not light depended. Levulinic acid inhibited completely the chlorophyll resynthesis indicating that the regulatory site on the biosynthetic pathway was located before protoporphyrin formation. Chlorophyllase activity changed during the dehydration and rehydration, but the chlorophyll content was not in direct correlation with this enzyme activity.

Quantification of transfer of 238U, 226Ra, 232Th, 40K and 137Cs in mosses of a semi-natural ecosystem

There is a lack of appropriate data on transfer of some radionuclides on many terrestrial biota groups. To expand the available data concentration ratios of (238)U, (226)Ra, (232)Th, (40)K and (137)Cs in mosses are presented in this paper. The relationship between concentration ratios of radionuclides and physicochemical characteristics of the underlying soil was also investigated. The data on concentration ratios obtained here will provide a useful addition to the currently used database of transfer parameters, particularly for natural radionuclides.

Trace Metals in Soils and Several Brassicaceae Plant Species from Serpentine Sites of Serbia

Abstract Serpentine soils from 16 sample points in Serbia as well as the roots and shoots of eight Brassicaceae family species: Aethionema saxatile, Alyssum montanum, Alyssum repens, Cardamine plumieri, Erysimum linariifolium, Erysimum carniolicum, Isatis tinctoria, Rorippa lippizensis, were analyzed with regard to their concentrations of P, K, Fe, Ca, Mg, Ni, Zn, Mn, Cu, Cr, Cd, and Pb. Most of the soil samples were typical of ultramafic sites with low concentrations of P, K and Ca and high concentrations of Mg, Fe, Ni and Zn. Ca/Mg ratio was <1 in most soil samples and Brassicaceae plants. Only in A. montanum, A. repens, E. linariifolium and R. lippizensis was the Ca/Mg ratio >1. The levels of P, K, Fe and Zn were high, Mn and Cu occurred in low amounts, whereas Cr, Cd, Co and Pb were only traceable. In the roots and shoots of A. montanum and A. repens the measured concentrations of Ni were 657 mg kg-1 and 676 mg kg-1 respectively, which is the first instance that such high concentrations of Ni were detected in these two species.

Transfer of natural and anthropogenic radionuclides to ants, bryophytes and lichen in a semi-natural ecosystem

Few data are available to quantify the transfer of both natural and anthropogenic radionuclides to detritivorous invertebrates to facilitate estimation of the internal dose to such biota in models used to assess radiation exposure. To enhance the available data, activity concentrations of 137Cs, 40K, 90Sr, 239 + 240Pu, 241Am, 235U and 238U were measured in ants (Formicidae) and corresponding undisturbed soil collected from the Zlatibor mountain in Serbia and ant/soil concentration ratios (CR) calculated. The 241Am concentration ratios for ants were fourfold higher than those calculated for ants in a previous study whereas they are similar to the more numerous data previously reported for a range of detritivorous invertebrates in other studies. CR values for 137Cs in ants were similar to the few other reported values and slightly lower than those for a range of detritivorous invertebrates. Those for 239 + 240Pu were slightly higher than those for ants in two other studies but they were close to upper limit of a range of data reported for detritivorous invertebrates. All the CR values will be included in a future revision of the ERICA Tool database and will particularly improve the information available for uranium.

Strategies of heavy metal uptake by three Armeria species growing on different geological substrates in Serbia

This study surveyed three species of the genus Armeria Willd. from five ultramafic outcrops, two non-ultramafic (schist) soils, and one tailing heap of an abandoned iron-copper mine from Serbia. Similarities and differences among the three Armeria species growing on different geological substrates in the ability to control uptake and translocate nine metals were examined. Chemical characteristics of the soil and plant samples (concentrations of P2O5, K2O, Ca, Fe, Mn, Ni, Zn, Cu, Cr, Co, Cd, and Pb) are presented. In order to assess accumulative potential of these three Armeria species, biological concentration, accumulation, as well as translocation factors were used. Three investigated Armeria species growing on eight different localities showed large differences in heavy metal uptake, translocation, and accumulation. The differences were present among the plant samples of the same species and even more among three different Armeria species and were primarily the result of the different contents of available heavy metals in the investigated soils. Additionally, differences might be the consequence of diverse responses and possible presence of supplementary resistance mechanisms in the plants from the ultramafic soils. None of the three Armeria species showed shoot hyperaccumulative potential for any of the investigated heavy metals and they could be considered as root accumulators, considering their potential to accumulate medium to large amounts of Zn (BCF up to 134), Cr (BCF up to 148), and Cd (BCF up to 9) in their roots.

Differences in trace element profiles of three subspecies of Silene parnassica (Caryophyllaceae) growing on ophiolitic substrate

The aim of the present study was to compare trace element profiles and the differences in uptake and translocation of trace elements in plants from five populations (three from Greece and two from Serbia) belonging to three subspecies of Silene parnassica Boiss. & Sprun. growing on ophiolitic substrates. For comparison of the subspecies, bioconcentration and translocation factors were used, as well as Spearman’s rank correlation coefficients for concentrations of elements in root and shoot samples. Chemical characteristics of the soil samples (pH, organic C, P2O5, K2O, Ca, Fe, Mg, Mn, Ni, Zn, Cu, Cr, Co, Cd and Pb) and plant samples (P2O5, K2O, Ca, Fe, Mg, Mn, Ni, Zn, Cu, Cr, Co, Cd and Pb) were determined, as well as bioconcentration and translocation factors and correlation matrices. All the three subspecies acted as strong Ni accumulators, with equal concentrations of Ni in roots and shoots, the values being several times higher than 100 mg kg–1, exceeding concentrations of available Ni in the soil. Concentrations of Cu and Cr in the aboveground plant tissues in samples from three localities were several times higher than expected, even for plants growing on metalliferous soils, exceeding, by multiple times, the available concentrations in the soil samples.

Protein molecular forms of insulin-like growth factor binding protein-2 change with aging

Aging is considered to be an adaptive mechanism to altered needs of an organism and/or to altered stimuli. Plasma concentrations of insulin-like growth factor binding protein-2 (IGFBP-2) increase with age and it is generally assumed that IGFBP-2 is a negative predictor of healthy aging. The aim of this study was to examine the distribution of IGFBP-2 molecular forms in different age groups and, specifically, the relationship between IGFBP-2 and alpha-2-macroglobulin (α2M). The relative amount of monomer IGFBP-2 was the highest in young persons, making up approximately 2/3 of the total circulating IGFBP-2. This gradually decreased with age down to 1/3 of total IGFBP-2 in elderly individuals. Fragmented IGFBP-2 increased with age and contributed almost 60% to the total immunoreactive IGFBP-2 in the age group 61-80 years. IGFBP-2/α2M complexes represented 10-12% of the total IGFBP-2 in the two younger groups but half this level in the oldest group. The significance of these changes and whether they affect more IGF-dependent or independent interactions are unknown. Due to drastic proteolysis of IGFBP-2, it may be postulated that either over-release of IGFBP-2-bound IGFs causes unwanted events or IGFBP-2 fragments are able to over-stimulate cellular processes.

Metal accumulation in populations of Calamagrostis epigejos (L.) Roth from diverse anthropogenically degraded sites (SE Europe, Serbia)

Heavy metal accumulation is recognized as a very important global pollution problem in the last decades. Plant species have been recognized as natural bioindicators of environmental pollution, especially the amount of heavy metals in soils. Moreover, only a limited number of plant species can survive in highly contaminated soils. It is also known that metal accumulation can vary greatly among different populations of the same species. This study examines the chemical composition and accumulation potential of the expansive clonal grass Calamagrostis epigejos at five localities exposed to different levels of anthropogenic pressure. Considerable differences were observed between uptake, translocation, and accumulation of total and available heavy metals, such differences corresponding to soil physico-chemical characteristics and the level of site pollution. The results indicate that Calamagrostis epigejos uptakes a significant portion of the available fraction of heavy metals in the soil and stores it in the roots, thereby exhibiting a certain potential for metal phytostabilization.