László Simon

Cadmium accumulation and distribution in sunflower plant

Abstract Cadmium (Cd) accumulation and distribution was studied in sunflower (Helianthus annuus L., public line HA‐89) plant. From an uncontaminated sandy loam brown forest soil with 162 μg kg‐1 HNO3/H2O2 extractable Cd the HA‐89 sunflower public line accumulated 114 ug kg‐1 Cd in its kernels under open field conditions. This value is rather low as compared to data found by others. Sandy loam brown forest soil was treated with 0, 1 or 10 mg kg‐1 of Cd to study the interaction of this heavy metal with young sunflower plants in a greenhouse pot experiment. The fresh weight and dry matter accumulation of sunflower plant organs (roots, shoots, leaves or heads) was unaffected by cadmium treatment of soil. The nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), copper (Cu), iron (Fe), manganese (Mn), or zinc (Zn) uptake of sunflower plant organs was not influenced by lower or higher Cd‐doses, except sunflower heads where 10 mg kg‐1 of Cd treatment of soil significantly reduced the uptake ...

Chicory (Cichorium intybus L.) and dandelion (Taraxacum officinale Web.) as phytoindicators of cadmium contamination

Chicory (Cichorium intybus L.) and dandelion (Taraxacum officinale Web.) were demonstrated to be potential indicator plants for heavy metal contaminated sites. Chicory, grown with 0.5–50 μM cadmium (Cd) in nutrient solution, accumulated 10–300 μM Cd g−1 in shoots and 10–890 μg Cd μg−1 in roots and rhizomes. With dandelion, 20–410 μg Cd μg−1 was found in shoots and 20–1360 μg Cd μg−1 in roots and rhizomes. An inverse correlation existed between chlorophyll and Cd concentrations in shoots of both species. Accumulation of Cd from nutrient solution was similar with the counter-anions SO42−, Cl1− and NO3− in chicory. In chicory grown in Cd-amended (11.2 kg Cd ha−1 applied five years previously) soils, Cd concentrations were substantially higher than in controls in all plant parts following the order: leaf > caudex > stem > root and rhizome. The above trend was the opposite of that observed in solution culture, where Cd accumulation was higher in roots and rhizomes than in shoots. Higher cadmium accumulation was found from a Cd-treated sand (Grossarenic Paleudult) than from a loamy sand (Typic Kandiudult) soil type. Chicory and dandelion are proposed indicator plants of cadmium contamination, and both have the potential to be an international standard heavy phytomonitor species of heavy metal contaminantion.

Aluminum toxicity in tomato. Part 1. growth and mineral nutrition

Abstract Aluminum (Al) toxicity was studied in two tomato cultivars (Lycopersicon esculentum Mill. ‘Mountain Pride’ and Floramerica) grown in diluted nutrient solution (pH 4.0) at 0, 10, 25, and 50 μM Al levels. In the presence of 25 and 50 μM Al, significant reduction was found in leaf area, dry weight, stem length, and longest root length of both cultivars. Growth of ‘Floramerica’ was less sensitive to Al toxicity than growth of ‘Mountain Pride’. Elemental composition of the nutrient solutions were compared immediately after the first Al addition and four days later. The uptake of micronutrients copper (Cu), manganese (Mn), molybdenum (Mo), zinc (Zn), boron (B), and iron (Fe) from the nutrient solution was reduced in both cultivars with increasing Al levels. Nutrient solution Al gradually decreased in time for every treatment; less in cultures of ‘Floramerica’ than in ‘Mountain Pride’. Aluminum treatments decreased the calcium (Ca), potassium (K), magnesium (Mg), Mn, Fe, and Zn content in the roots, st...

Aluminum toxicity in tomato. Part 2.Leaf gas exchange, chlorophyll content, and invertase activity

Abstract The effect of aluminum (Al) toxicity on leaf gas exchange, leaf chlorophyll content, and sucrose metabolizing enzyme activity of two tomato cultivars (Lycopersicon esculentum Mill. ‘Mountain Pride’ and ‘Floramerica) was studied to determine the mechanism of growth reduction observed in a related study (Simon et al., 1994, Part 1). Plants were grown in diluted nutrient solution (pH 4.0) with 0, 10, 25, or 50 μM. Al for 16 days. Leaf gas exchange was reduced 2–3 fold in both cultivars as Al concentration increased. Gas exchange of ‘Mountain Pride’ was more sensitive to Al toxicity than ‘Floramerica’, agreeing with growth responses observed. Reductions in carbon dioxide (CO2) assimilation rate appeared to be due to nonstomatal factors in ‘Floramerica’, but stomatal and non‐stomatal limitations in ‘Mountain Pride’. Chlorophyll content of leaves was not affected by Al. Acid invertase (AI) and neutral invertase (NI) activity of roots responded consistently to Al concentration in both cultivars. Root A...

Evaluation of three herbaceous index plant species for bioavailability of soil cadmium, chromium, nickel and vanadium

Uncultivated plants growing on disturbed sites may be useful for assessing the bioavailability of some metals in soils, and thus the potential for metal mobilization up the terrestrial food chain, an important element in ecological risk assessment. A planted chicory cultivar (Cichorium intybus L. var. foliosum Hegi.) and the uncultivated plants horseweed (Canada fleabane) (Erigeron canadensis L.) and dogfennel (Eupatorium capillifolium (Lam.) Small) were evaluated for their ability to act as index plant species for soil Cd, Cr, Ni, and V at two field sites where these metals had been applied five yr previously to two highly weathered sandy Ultisols. Soil Cd was available to all analyzed plant tissues of all three plant species at both sites, particularly on the sandier Blanton soil. Chicory was an effective index plant for Cd on the finer textured Orangeburg soil but functioned as an indicator plant (toxicity symptoms were observed) on the sandier Blanton soil. Horseweed and dogfennel were effective index plants for Cd in both contaminated soils. Soil Cr, Ni, and V were less bioavailable than soil Cd and plant metal uptake was more sensitive to residual soil Cr, Ni, and V than was soil extraction with double acid. Horseweed and chicory may have potential as index plants for soil Cr. Chicory may have potential as a Ni index plant. Chicory and dogfennel may have potential as V index plants.

Impact of picolinic acid on the chromium accumulation in fodder radish and komatsuna.

Effects of picolinic acid (2-pyridinecarboxylic acid) and chromium(III) picolinate was studied on the chromium (Cr) accumulation of fodder radish (Raphanus sativus L. convar. oleiformis Pers., cv. Leveles olajretek) and komatsuna (Brassica campestris L. subsp. napus f. et Thoms. var. komatsuna Makino, cv. Kuromaru ) grown in a pot experiment. Control cultures, grown in an uncontaminated soil (UCS; humous sand with pHKCl 7.48, sand texture with 12.4% clay+silt content, organic carbon 0.56%, CaCO3 2.2%, CEC 6.2 cmolc kg−1, Cr 10.6 mg kg−1), accumulated low amounts of chromium (less than 5.4 μg g−1) in their roots or shoots. When this UCS was artificially contaminated with 100 mg kg−1 Cr (CrCl3) later picolinic acid treatment promoted the translocation of chromium into the shoots of both species. In fodder radish shoots Cr concentration reached 30.4 μg g−1 and in komatsuna shoots 44.5 μg g−1. Application of ethylene diamine tetra-acetic acid (EDTA) to this Cr contaminated soil had similar effect to picolinic acid. When the UCS was amended with leather factory sewage sediment (which resulted in 853 mg kg−1 Cr in soil), Cr mobilization was observed only after repeated soil picolinic acid applications. From a galvanic mud contaminated soil (brown forest soil with pHKCl 6.77, loamy sand texture with 26.6% clay+silt content, organic carbon 1.23%, CaCO3 0.7%, CEC 24.5 cmolc kg−1, Cd 5.0 mg kg−1, Cr 135 mg kg−1, and Zn 360 mg kg−1) the rate of Cr mobilization was negligible, only a slight increase was observed in Cr concentration of fodder radish shoots after repeated picolinic acid treatments of soil. Presumably picolinic acid forms a water soluble complex (chromium(III) picolinate) with Cr in the soil, which promotes translocation of this element (and also Cu) into the shoots of plants. The rate of complex formation may be related to the binding forms and/or concentration of Cr in soil and also to soil characteristics (i.e. pH, CEC), since the rate of Cr translocation was the following: artificially contaminated soil > leather factory sewage sediment amended soil > galvanic mud contaminated soil. Four times repeated 10 mg kg−1 chromium(III) picolinate application to UCS multiplied the transport of chromium to shoots, as compared to single 10 mg kg−1 CrCl3 treatment. This also suggests that chromium(III) picolinate is forming in the picolinic acid treated Cr-contaminated soils, and plants more readily accumulates and translocates organically bound Cr than ionic Cr. Picolinic acid promotes Cr translocation in soil-plant system. This could be useful in phytoextraction (phytoremediation) of Cr contaminated soils or in the production of Cr enriched foodstuffs.

EFFECTS OF ZIRCONIUM ON THE GROWTH AND PHOTOSYNTHETIC PIGMENT COMPOSITION OF CHLORELLA PYRENOIDOSA GREEN ALGAE

The effects of zirconium (Zr) were investigated on the growth rate, dry matter accumulation, and elemental and photosynthetic pigment composition of Chlorella pyrenoidosa green algae. Algae were treated with 0.1–50 μM (≈ 0.009–4.561 mg dm−3) of Zr; inorganic compounds (Zr oxychloride, Zr nitrate) and organic chelates (Zr ascorbate or Zr citrate) were applied. All Zr compounds displayed only a slight insignificant inhibitory effect on the growth rate of algae. Treatment of algae with 1 μM Zr (as Zr ascorbate, a water soluble pH stable chelate) slightly stimulated and 5–50 μM Zr slightly inhibited the dry matter accumulation of Chlorella. Zirconium concentration in the nutrient solution decreased rapidly during the algae propagation, and Chlorella cells accumulated significant amounts of Zr. In the case of 1 μM Zr (Zr ascorbate) treatment, 60.6 μg g−1 Zr was found in the washed cells; after 50 μM Zr application this value was 441 μg g−1 Zr. Zirconium treatment reduced the P, Mg, Cu, and Ti concentrations in algae cells, and the concentration of Fe, Mn, and partly Zn was enhanced. Chlorophyll a, chlorophyll b, xanthophyll, and carotenoid concentrations were equally reduced by 13–33% in Zr-treated cultures. Zirconium treatment changed the chlorophyll a:chlorophyll b ratio and caused appearance of several new chlorophyll derivatives in Chlorella.

Impact of Pseudomonads and Ethylene on the Cadmium and Nickel Rhizofiltration of Sunflower, Squash, and Indian Mustard

Three hydroponic experiments were set up to study the rhizofiltration of cadmium (Cd) or nickel (Ni) from artificially contaminated nutrient solution with sunflower, squash, or Indian mustard. After 48 h of exposure with 2 mg L−1 Cd‐contaminated water, 460, 415, or 1092 µg Cd g−1 (dry weight) was detected in roots of 33‐day‐old sunflower and squash or in 50‐day‐old Indian mustard, respectively. As calculated, 1 g of root dry matter of the tested crop species removed 5.7–12.4% of total Cd content present in the nutrient solution. It was supposed that pseudomonads (soil rhizoplane bacteria) and the plant growth hormone ethylene can enhance the specific surface of roots and hence roots metal adsorption capacity. As a trend, pretreatment of Indian mustard with Pseudomonas fluorescens bacteria enhanced slightly the Cd (from 1793 to 2346 µg g−1) or Ni (from 1088 to 1192 µg g−1) concentration of roots. Cadmium concentration in roots was also enhanced from 2694 to 3273 µg g−1 when the roots of Indian mustard were pretreated with Cd‐tolerant rather than Cd‐sensitive Pseudomonas cepacia. In spite of the occurrence of new root hairs, the pretreatment of roots with ethylene proved to be ineffective in enhancement of the Cd rhizofiltration capacity of Indian mustard.

Effect of gallium on photosynthetic pigments and peroxidase activity of Chlorella pyrenoidosa

Abstract Green algae (Chorella pyrenoidosa) were grown in iron‐deficient and normal iron supplied nutrient solution and treated with 1 uM gallium. Treatment with gallium enhanced the growth rate and chlorophyll content of algae cultures. Significant changes were recorded in individual photosynthetic pigment composition of treated cultures. In both iron‐deficient and normal iron supplied cultures, gallium treatment enhanced peroxidase enzyme activity. Partially purified peroxidase showed different kinetic properties in the samples treated with gallium. An iron‐gallium interaction is proposed that affects chlorophyll metabolism and peroxidase activity in green algae.

Sensitive or tolerant adaptation of rhizobium bacteria as a function of the short- or long-term loads of the zinc metal salt

Department of Land and Environmental Management, College of Nyiregyhaza, Nyiregyhaza, Hungary. Introduction The heavy metals or toxic elements are posing serious problems in the various soil-plant ecosystems of the world (Mathe-Gaspar et al. 2006). In case of the beneficial microbes, such as the nitrogen-fixing Rhizobium bacteria, or the phoshorus-mobilising arbuscular mycorrhizal fungi (AMF), however there is a discrepancy in the literature regarding their metal tolerant abilities and their functions in the plant performance and plant fitness (Biro et al. 1998, Takacs et al. 2006). The trustable long-term field experiments, which are not so frequent in Europe, can serve therefore, as valuable tools to study those effects and the behaviour of the heavy metals among the natural conditions (Kadar and Nemeth, 2005). Other studies can show mainly the direct effect of the metals, but due to the multifactorial manner of the environmental conditions, only the long-term experiments can show both the abundance and the functioning of the plant-microbe interactions. It is also known, that the effect of heavy metals can be different, if other amendments, such as the organic or inorganic additives, or soil conditioners are given to the metal-polluted soils (Posta, Fuleky 1997; Simon, Biro 2005). In such soils the introduction of the higher plants can be more successful by increasing the relevance of the soil-technological and phytoremediation techniques (Lakatos et al. 2001). The combination of those procedures with the metal-tolerant beneficial microbes and/or microsymbionts can have further benefits, ie. stabilising the metals in the rhizosphere and improve the nutrient supply or the growth and fitness of the higher plants (Simon, Biro 2005; Vivas et al. 2006). Among the field conditions a particular pattern of the metal- or salt-tolerant abilities was found seasonally and annually (Biro et al. 1999, Naar and Biro 2006, Fuzy et al. 2006). Depending on the severity of the stress the beneficial microbes could confer the stress-tolerant abilities toward the macrosymbiont hosts (Vivas et al. 2006), more particularly if they are well-adapted to the certain environment. Other findings with non-adapted fungi have shown also the potential applicability of the symbiosis in the other way of the phytoremediation, such as the phytoextraction (Takacs and Voros 2003). Some of the toxic elements, i.e. the As and Se could even more intensify the microbial functioning of the nitrogen-fixing abilities of the rhizobium bacteria (Biro et al. 1999). At the different Cd loads, the role of the AM fungi was found to be the part of the surviving mechanism, as well. But how the adaptation process is developed in a particular population (among the most sensitive nitrogen-fixing rhizobia), when applying the same heavy metal loads within a shorter or a longer application periods? How the known essential Zn micronutrient become a toxic element in the sewage sludge treated soil? Those questions are addressed in the study.