Slobodanka Pajević

Heavy metal accumulation of Danube river aquatic plants — indication of chemical contamination

In this paper, the ecological status of a section of the Danube River flowing through Serbia from Bezdan to Djerdap was evalutated. Using the chemical composition of water, sediment samples from the littoral zone and dominant aquatic macrophytes, the level of chemical pollution was ascertained. Chemical analyses of the water and sediment indicated that the tributaries flowing into the Danube significantly influenced the chemical load of the water and as a direct consequence, the sediment. The concentration of heavy metals including Cu, Mn and Cd found in plants of the Potamogeton genus, further indicated significant chemical pollution, establishing a clear link between the chemical composition of plant tissues and the chemical composition of water and sediment. This paper therefore describes how the chemical composition of aquatic plants can be used as a reliable indicator for heavy metal pollution of aquatic ecosystems.

Primary production dynamics of dominant hydrophytes in Lake Provala (Serbia)

The objective of this investigation was to analyze the primary production of the dominant hydrophytes by monitoring levels of organic matter and organic carbon and estimating photosynthetic potential via the total chlorophyll content. The survey was conducted in Lake Provala (Serbia) throughout the peak vegetation period of the year 2000. The contents of organic matter and organic carbon for Myriophyllum spicatum L. were 105.11 g m−2 and 73.66 g m−2, Nymphoides peltata (Gmel.) Kunt. were 95.51 g m−2 and 45.26 g m−2 and Ceratophyllum demersum L. were 52.17 g m−2 and 29.75 g m−2. Chlorophyll A (Chl a) and chlorophyll A+B (Chl a+b) pigments ranged from 1.54 mg g−1(Chl a) and 2.1 mg g−1(Chl a+b) in M. spicatum to 5.27 mg g−1(Chl a) and 7.53 mg g−1(Chl a+b) in C. demersum. At full leaf out, the latter aquatic plants exceeded 50% cover of the open water surface. All species achieved maximum growth in June, but significant differences in growth dynamics were observed. At the end of the vegetation period, these plants sink to the bottom and decompose

Phytoextraction of Heavy Metals by Fast-Growing Trees: A Review

Phytoextraction, as the most commonly used technique in phytoremediation, involves the utilization of plant-hyperaccumulators for the absorption pollutants (primarily heavy metals) from the environment, their transport, and concentration in the biomass of harvestable organs. This in situ, cost-effective technology could improve the quality of moderately contaminated lands and waters within realistic time scales. For a successful implementation of phytoextraction, the main prerequisite is to identify native plants which are able to extract (absorb), degrade, or sequester hazardous contaminants from growing media and develop strategies for making hybrids and genetically modified plants which are good candidates for phytoextraction. Because of their rapid growth rate and high biomass yield, their adaptability to different ecological conditions and genetic variability is outstanding. Willows and poplars from the Salicaceae family are valuable resources for the use of phytoremediation. Also, species like the eucalypt, black locust, birch, and paulownia are defined by numerous researchers as good candidates for phytoextraction due to their high metal bioconcentration ability and high yield. There have been numerous studies confirming that species with a role in phytoextraction developed a complex network of homeostatic metabolic mechanisms in order to control metal uptake, accumulation, (re)distribution, and detoxification.

Magnesium and iron deficiencies alter Cd accumulation in Salix viminalis L.

ABSTRACT Evidence exists that Cd and certain nutrient elements, such as Fe and Mg, could share similar mechanisms of plant uptake and accumulation. Here we report that Mg and Fe deficiency in mature plants of Salix viminalis, grown in hydroponic solutions containing 5 µg ml−1 of Cd, caused a significant increase in Cd accumulation in roots, stems and leaves. Cd (µg g−1 dry weight) was determined following three treatments: 1) Cd treatment in complete nutrient solution; 2) Cd treatment with Fe deficiency; and 3) Cd treatment with Mg deficiency, yielding, respectively: in young leaves (65.3, 76.1, and 92.2), mature leaves (51.5 to 76.3 and 87.1), upper stems (80.6, 116.8, and 130.6) lower stems (67.2, 119, and 102.3), roots (377.1, 744.8, and 442,5). Our results suggest that Cd utilizes the same uptake and transport pathways as Mg and Fe. Evidence exists that Mg and Fe uptake and translocation could be further facilitated by plants as an adaptive response to deficiency of these elements. Such physiological reaction could additionally stimulate Cd accumulation. Although Cd uptake was mostly confined in roots, high Cd content in aerial plant parts (51.5–130.6 µg g−1) indicates that the analysed Salix viminalis genotype is suitable for phytoextraction.

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.

Photosynthetic and biochemical characteristics of invasive species ( Ambrosia artemisiifolia L., Ambrosia trifida L. and Iva xanthifolia Nutt. ) depending on soil humidity and phenological phase

Environmental factors like temperature and soil humidity are recognized as influencing factors on photosynthetic response and organic productivity, distribution and biochemical characteristics of plants. Here we present measurements of gas exchange parameters, water-use efficiency (WUE) and nitrogen-use efficiency (NUE) of field-grown invasive species Ambrosia artemisiifolia L., Ambrosia trifida L. and Iva xanthifolia Nutt., in order to define their potentials as colonizers. Biogenic volatile organic compounds (BVOC) in leaves and flowers depending on soil humidity were also investigated.Results indicated species A. artemisiifolia as the colonizer with the highest physiological potential because of its high WUE in its vegetative phase and also the highest NUE and the highest photosynthesis/dark respiration ratio in its flowering phenological phase. It was found that the volatile compounds of Ambrosia species and Iva xanthifolia consist mainly of terpenic compounds. There was a significant difference among the species regarding qualitative composition of monoterpens and sesquiterpens and specific qualitative and quantitative ratio of monoterpens in flowers and leaves of A. artemisiifolia.

Hydroponic screening of black locust families for heavy metal tolerance and accumulation.

abstract Present work examines phytoextraction potential of four black locust families (half-sibs 54, 56, 115, and 135) grown hydroponically. Plants were treated with 6 ppm of cadmium (Cd), 100 ppm of nickel (Ni), and 40 ppm of lead (Pb) added in Hoagland nutrient solution, accompanying with simultaneously applied all three metals. Responses to metals exposure among families were different, ranging from severe to slight reduction of root and shoot biomass production of treated plants. Calculated tolerance indices are indicating tested families as highly tolerant (Ti > 60). Family 135 had the lowest tolerance index, pointing that it was highly susceptible to applied metals. Comparing photosynthetic activities of tested families it has been noticed that they were highly sensitive to stress induced by heavy metals. Net photosynthetic rate of nickel treated plants was the most affected by applied concentration. Cadmium and nickel concentrations in stems and leaves of black locust families exceeded 100 mg Cd kg−1 and 1000 mg Ni kg−1, in both single and multipollution context. On the contrary, accumulation of lead in above ground biomass was highly affected by multipollution treatment. Tf and BCF significantly varied between investigated treatments and families of black locust. Concerning obtained results of heavy metals accumulation and tolerance of black locust families can be concluded that tested families might be a promising tool for phytoextraction purposes, but it takes to be further confirmed in field trials.

Responses of Wheat (Triticum Aestivum L.) and Maize (Zea Mays L.) Plants to Cadmium Toxicity in Relation to Magnesium Nutrition

Abstract The influence of cadmium (Cd) on physiological processes in wheat (Triticum aestivum L.) and maize (Zea mays L.) plants exposed to either optimal mineral nutrition or the absence of magnesium (Mg) as well as the accumulation of cadmium and magnesium in plant organs were studied using the method of water culture in a greenhouse. Cd treatment reduced shoot fresh mass more strongly in Mg-supplied than in Mg-deficient plants. Negative effect of Cd on photosynthetic activity was more pronounced in T. aestivum than in Z. mays plants. Cd treatment decreased leaf chlorophyll and carotenoid concentration in both Z. mays and T. aestivum, irrespective of the Mg supply. Cd was preferentially accumulated in the roots of both species. Catalase activity in T. aestivum leaves and roots was unaffected by Cd and Mg supply. Cd treatment did not affect Fe accumulation in the leaves of either species, while in the roots a considerable increase occurred, irrespective of the Mg nutrition. Higher tolerance of Z. mays and T. aestivum plants to Cd toxicity exposed to Mg deficiency could partly be ascribed to the preservation of Fe nutrition.

Daily dynamics of photosynthetic parametersin beech population under periodical droughtconditions

Abstract The paper presents the impact of periodic soil drought on physiological parameters important for bioproductivity of mountain beech populations. The investigated forest population was located near Fruška gora mountain peak, where water runs off quickly, and consequently lack of soil humidity develops very often. Decreasing trends of photosynthesis, transpiration, water use efficiency and stomatal conductance (gs) during the growing season were evident, in correlation with a shortage of precipitation. Diurnally, photosynthesis of beech leaves showed rhythmical changes. It was the most intensive in the morning, then decreased between noon and 1 pm, and increased again during early afternoon. High leaf temperature and water deficit in the deeper soil layers caused a decreasing trend in photosynthesis and daily rhythmic changes of the transpiration rate and water use efficiency. Although surface soil water capacity did not show a significant decreasing trend from July to September, a lack of precipitation was observed, which probably caused a lack of moisture in deeper soil layers, resulting in a decline in photosynthesis and transpiration. Physiological status, linked to primary photosynthetic productivity of forests, could be a significant indicator of environmental conditions and trends in climate changes.

Comparative assessment of mineral elements and heavy metals accumulation in vegetable species

The heavy metal (cadmium, lead, nickel, chromium) and mineral element (potassium, phosphorus, calcium, magnesium) levels in edible parts of tomato, potato, spinach, beetroot, parsley, parsnip, carrot, cauliflower, pepper and broccoli were determined by atomic absorption spectrophotometry. Six samples for each species originating from different localities were collected from green markets. The heavy metal concentrations ranged from calcium > phosphorus > magnesium. The highest mean levels of the heavy metals, as well as of potassium, calcium and magnesium, were found in spinach. A large number of samples containing high levels of toxic heavy metals, especially of cadmium and lead, impose the necessity for strict regulative guidelines concerning individual vegetable crops production, harvest, handling and storing, in order to diminish possibility of contamination.