Exposure to High Concentrations of Cadmium Which Delay Development of Ostrinia Nubilalis Hbn. Larvae Affected the Balance of Bioelements.

All processes involved in metal homeostasis must be coordinated to provide sufficient, but not toxic, concentrations of important bioelements, and to minimize detrimental effects of toxic metals. Our previous studies dealing with the exposure of O. nubilalis non-diapausing larvae to dietary Cd demonstrated that exposure to higher concentrations of Cd caused delay in the development of larvae, induced oxidative stress and also induced defense mechanisms against the toxic effects of Cd. The aim of the present study was to evaluate how acute and chronic exposure of O. nubilalis larvae to increased concentrations of dietary Cd affected the balance of important bioelements. The concentration of bioelements was analyzed in larvae (after short-term exposure) and pupae (after long-term exposure). The short-term exposure of final instar larvae (L5) to Cd did not affect significantly the concentration of any of the analyzed bioelements, while the long-term exposure of developing larvae to higher concentrations of Cd caused increase in the concentrations of Ca, Mg and Na in pupae. The bioaccumulation factor, calculated for bioelements after long-term exposure to Cd, was higher for the most bioelements in groups fed with diet containing higher concentrations of Cd, except K which displayed the opposite trend. Pearson correlation coefficient showed positive correlations between Cd and Ca, Mg, Na, Fe, Cu and Zn, while negative correlation was observed between Cd and K. The results indicate that impact on the balance of important bioelements might be one of the mechanisms of cadmium toxicity and certainly raise numerous questions for future research.

Phytoremediation potential of the naturally occurring wetland species in protected Long Beach in Ulcinj, Montenegro.

Long Beach, situated in southern Montenegro, is subject to considerable biogenic and abiogenic influences. Thus, analyzing total heavy metal content in soil and plants in this region is, while challenging, highly important in order to assess the level for determining the soil degradation level and the phytoremediation potential of naturally growing salt marsh species. This area together with a Bojana river and backshore forms a real vegetation mosaic where habitats of various types coexist. Therefore, it represents good model system. In the present study, the levels of As, Al, B, Cd, Co, Cr, Cu, Hg, Fe, Mn, Mo, Ni, Pb and Zn in coastal soils as well as in eight salt marsh plants: Bolboschoenus maritimus, Juncus acutus, Juncus anceps, Juncus articulatus, Juncus gerardii, Juncus maritimus, Scirpus holoschoenus and Schoenus nigricans, were investigated in order to identify the plant species that can be used for the remediation of polluted sites, especially those located along the coastline. The obtained results show that species J. gerardii, J. articulatus and B. maritimus can be clearly separated from J. acutus, J. anceps, J. maritimus, S. holoschoenus and Sh. nigricans based on the degree of heavy metal accumulation in various organs. Moreover, analyses revealed that the bioaccumulation factor of underground organs is significantly higher relative to that of the aboveground parts for almost all investigated metals and species. The bioaccumulation factor had the highest value in the underground organs of J. gerardii and B. maritimus, where a value of 3.37 was measured for B and 2.54 for Hg, respectively. Hence, as all investigated species are "underground accumulators" for most of the analyzed metals, they could be useful for phytostabilization and phytoremediation of B and Hg in particular. Moreover, each plant species can be used in the phytoremediation process targeting specific heavy metals.

Mercury content in agricultural soils (Vojvodina Province, Serbia).

The Vojvodina Province in northern Serbia is well known for its intensive field crops production. Over 90 % of total arable land, which represents more than 1500.000 ha, is used for field or vegetable crop production. A grid superimposed on Vojvodina land by means of a GIS tool (GIS ArcView 10) has divided land into 4 × 4 km units, each representing an area of 1600 ha. Total number of 1370 bulked soil samples were taken (0-30 cm depth) from agricultural land and analysed for total mercury content THg. The samples were analysed using Direct Mercury Analyzer DMA 80 Milestone. Quality control was carried out with IRMM BCR reference materials 143R. The aim of this study was to determine the total content of Hg in agricultural soils and its spatial distributions in different parts of Vojvodina Province. The obtained results were within interval 0.008-0.974 mg kg-1. The average concentration of Hg was 0.068, with median 0.048 mg kg-1. The correlation was determined between Hg concentration and organic matter content in the soil. Content of Hg coincides with main geomorphological units of Vojvodina Province. Average values of Hg concentrations for soils formatted on different geomorphological units were 0.031 for sandy area with dune fields, 0.048 for alluvial terraces, 0.055 for upper Pleistocene terraces, 0.058 for loess plateaus, 0.083 for mountains and 0.092 mg kg-1 for alluvial plains. Hg spatial distribution confirmed that most of Vojvodina Province area has geochemical origin of Hg. Higher concentration of Hg on alluvial plains indicated that the origin of Hg near rivers could be from anthropogenic source. The main rivers in Vojvodina have been dammed more than a century ago. Thus, higher concentrations of Hg in their alluvial plains out of narrow dammed zone around the rivers must be related to natural and anthropogenic sources located in their huge catchments. Higher content of Hg in mountain region can be explained by high clay content in these soils. Additional hotspots of Hg concentration of top soils are related to geographical locations of major towns. The obtained results also indicated that the measured levels of Hg in the soil are not limiting factors for production of safe food in Vojvodina.

Drought Impact Is Alleviated in Sugar Beets (Beta vulgaris L.) by Foliar Application of Fullerenol Nanoparticles.

Over the past few years, significant efforts have been made to decrease the effects of drought stress on plant productivity and quality. We propose that fullerenol nanoparticles (FNPs, molecular formula C60(OH)24) may help alleviate drought stress by serving as an additional intercellular water supply. Specifically, FNPs are able to penetrate plant leaf and root tissues, where they bind water in various cell compartments. This hydroscopic activity suggests that FNPs could be beneficial in plants. The aim of the present study was to analyse the influence of FNPs on sugar beet plants exposed to drought stress. Our results indicate that intracellular water metabolism can be modified by foliar application of FNPs in drought exposed plants. Drought stress induced a significant increase in the compatible osmolyte proline in both the leaves and roots of control plants, but not in FNP treated plants. These results indicate that FNPs could act as intracellular binders of water, creating an additional water reserve, and enabling adaptation to drought stress. Moreover, analysis of plant antioxidant enzyme activities (CAT, APx and GPx), MDA and GSH content indicate that fullerenol foliar application could have some beneficial effect on alleviating oxidative effects of drought stress, depending on the concentration of nanoparticles applied. Although further studies are necessary to elucidate the biochemical impact of FNPs on plants; the present results could directly impact agricultural practice, where available water supplies are often a limiting factor in plant bioproductivity.