Tünde Takács

The Arbuscular Mycorrhizal Status of Poplar Clones Selected for Phytoremediation of Soils Contaminated with Heavy Metals

Abstract The aim of this work was to study the colonization of indigenous arbuscular mycorrhizal fungi (AMF) species in fine-roots of poplar clones. Roots of 7 poplar clones were sampled from a 1-year-old trial established at an industrial site strongly polluted with heavy metals at Balatonfűzfő , Hungary. The poplar clones have shown variable degrees of colonization by AMF, suggesting differential host susceptibility or mycorrhizal dependency. After outplanting the percentage of poplar survival was strongly correlated with the frequency of AMF infection. Two clones that survived at the lowest ratio after outplanting had not been colonized by AMF in contrast to those which survived to a much higher extent.

Comparative Effects of Rock Phosphates on Arbuscular Mycorrhizal Colonization of Trifolium pratense L.

Abstract The effect of five rock phosphates with different solubility (from Algeria, North Florida, North Carolina, Senegal, and Morocco) and that of single superphosphate (SSP) alone or with lime was investigated on the root colonization of red clover with indigenous arbuscular mycorrhizal fungi (AMF). In a pot experiment, the phosphorus (P) sources were applied at four rates (0, 100, 400, and 1600 mg total P2O5 kg−1 dry soil) to an acidic sandy soil (Nyírlugos) and to an acidic clay loam soil (Ragály). The arbuscule content of the roots was more sensitive to various rock phosphates than the infection frequency. No mycorrhizal colonization of roots was observed in the Nyírlugos soil at the 1600 mg P2O5 kg−1 level of SSP or in either soil at the 1600 mg P2O5 kg−1 level of SSP+lime, indicating that the mycorrhizal dependency of the host was eliminated by the highest soluble P concentrations in the soil.

Environmental Impact of Soil Pollution with Toxic Elements from the Lead And Zinc Mine at Gyöngyösoroszi (Hungary)

Toxic elements from the lead (Pb) and zinc (Zn) mine at Gyöngyösoroszi (Northeast Hungary) cause pollution and potential risk to the ecosystem and human health. The aim of this work was to determine the contamination level at two sites planted with willow (Salix sp. L.) and corn (Zea mays L.) along the Toka valley, to evaluate soil quality by biological and biochemical parameters, and to assess potential risk for human health. Total arsenic (As), cadmium (Cd), copper (Cu), Pb, Zn, and mercury (Hg) contents in polluted soils reached values up to 384, 28.8, 493, 2827, 4417, and 4.46 mg kg−1, respectively. Values of these elements in the polluted soil for willow were 3.7 to 31 times higher and in corn were 2.3 to 20.9 times higher than in the unpolluted soil. All measured parameters therefore indicated soil pollution. Plant emergence percentage and plant and microbial biomass decreased whereas water‐extractable organic carbon (C), phosphatase activity, and corn root infection by arbuscular mychorrizal AM fungi and toxic metal content of the tested plants increased significantly. The results showed a high soil pollution level and consequently a great potential risk for human health (value of the additive hazard quotient was 11.21) and indicated the necessity for remediation of the site.

Effect of Five Phosphate Rocks on Red Clover (Trifolium pratense L.) Yield in Pot Trial

Abstract Phosphorus (P) availability in five phosphate rocks with different P solubility was compared with that in single superphosphate and superphosphate+lime in a pot experiment with red clover as test plant on a Lamellic Arenosol with sand soil texture and on a Haplic Luvisol with clay loam soil texture, both strongly acid with low P supply. Phosphorus rates in the pot experiment were 0, 100, 400, and 1600 mg total P2O5 kg−1. On both soils, there was a weak correlation between total added P and red clover P responses. If P solubility of the PRs was also taken into account, the correlation between formic acid–, citric acid–, or neutral ammonium citrate–soluble P amounts added and red clover responses became much stronger. Soil P availability was estimated by water, Olsen, Lakanen‐Erviö, and ammonium lactate tests. Among the P extractants studied, Olsen soil P test gave the best correlation with red clover yields.

Study of heavy metal uptake of Populus nigra in relation to phytoremediation

Introduction The emission of heavy metals due to anthropogenic activities is an increasing risk for the plant-animal-human food chain. Phytoremediation is regarded as an environmetal friendly cleanup method to rehabilitate soils, sediments or groundwater contaminated with inorganic or organic contaminants (Kimives et al., 2005; Mathene Gaspar and Anton, 2004; Robinson et al., 2006). There are many different kinds of pyhtoremediation technique based on processes of plant uptake such as phytostabilization, phytoextraction, phytovolatilization, rhizofiltration and phytodegradation. Phytoextraction is often used technique to remove heavy metals (HM) from soil and translocate HM’s into plants. Most of HM are accumulated in tissues of roots but several elements are translocated into the above-ground plant tissues. Uptake of heavy metals into plants through roots depends on the plant’s uptake efficiency, the transpiration rate, microbial activities in the rhizoshpere, the HM types and concentration and several soil factors (Adriano et al., 2004; Dietz and Schnoor, 2001). Poplars seem to be favorite and commonly used test plants (Quinn et al., 2001; Takacs et al., 2005) in phytoremediation due to their rapid growth rates, high evapotranspiration rates and ease of propagation. They have tolerance to a wide range of environmental conditions and ability to take up high levels of some contaminants (Quinn et al., 2001; Robinson et al., 2006). On the other hand, they are not part of food chain definietly. We investigated the heavy metal accumulation of poplar trees (Populus nigra) as test plants from soil loaded with five HMs (Cd, Zn, Pb, Ni, Mn) in a pot experiment. Concentrations of HM’s in roots, shoots and leaves were compared in different harvesting times (after 2, 4, 6 and 8 monthes).

Effect of Arbuscular Mycorrhizal Fungi on the Growth and Polyphenol Profile of Marjoram, Lemon Balm, and Marigold.

The aim of this study is to examine the effect of arbuscular mycorrhizal fungi (AMF) colonization on biomass, polyphenol profile, and content of economically important herbs. A pot experiment was performed with marjoram, lemon balm, and marigold applying a commercially available AMF mixture for inoculation. Major polyphenols were identified using HPLC-UV-ESI-qTOFMS on the basis of their UV-vis and mass spectral characteristics, and selected ones were quantified. We showed that AMF can provide different services for each herb. Marjoram had the highest level of fungal colonization (82 M%) followed by lemon balm (62 M%) and marigold (17 M%). AMF inoculation significantly increased the biomass of marjoram (1.5-fold), the number of marigold flowers (1.2-fold), and the yield of rosmarinic acid and lithospermic acid isomers of marjoram (1.5-fold) and lemon balm (1.2-fold). Therefore, the quantity and quality of plant material could be improved by the application of optimized AMF inoculum.

Simultaneous monitoring of electrical capacitance and water uptake activity of plant root system

Abstract Pot experiments were designed to test the applicability of root electrical capacitance measurement for in situ monitoring of root water uptake activity by growing cucumber and bean cultivars in a growth chamber. Half of the plants were inoculated with Funneliformis mosseae arbuscular mycorrhizal fungi, while the other half served as non-infected controls. Root electrical capacitance and daily transpiration were monitored during the whole plant ontogeny. Phenology-dependent changes of daily transpiration (related to root water uptake) and root electrical capacitance proved to be similar as they showed upward trends from seedling emergence to the beginning of flowering stage, and thereafter decreased continuously during fruit setting. A few days after arbuscular mycorrhizal fungi-colonization, daily transpiration and root electrical capacitance of infected plants became significantly higher than those of non-infected counterparts, and the relative increment of the measured parameters was greater for the more highly mycorrhizal-dependent bean cultivar compared to that of cucumber. Arbuscular mycorrhizal fungi colonization caused 29 and 69% relative increment in shoot dry mass for cucumbers and beans, respectively. Mycorrhization resulted in 37% increase in root dry mass for beans, but no significant difference was observed for cucumbers. Results indicate the potential of root electrical capacitance measurements for monitoring the changes and differences of root water uptake rate.

Site-Specific Optimization of Arbuscular Mycorrhizal Fungi Mediated Phytoremediation

Anthropogenic contamination of soils with toxic metals has become a global environmental problem. Managed mycorrhization promotes phytoremediation and reuse of damaged fields. Site-specific optimization can be defined as selection of a tolerant fungal strain that is compatible to plants, remediation sites and the bioremediation method to be adapted. The high inter- and intraspecific functional diversity and non-specific association of arbuscular mycorrhizal (AM) fungi provide biological materials to develop fungi host combinations for different soils and contaminants. Both ecological and human health aspects should, however, be considered while planning and designing the phytotechnologies for restoration of metal contaminated sites. Soil characteristics, metal concentration, composition of the indigenous AM fungi and plant community are some of the important factors in developing site-specific remediation technology. The research carried out during the last few years on the role of AM fungi in facilitating phytoremediation of heavy metal contaminated soils under field environment is highlighted.

Estimation of am fungal colonization - Comparability and reliability of classical methods

The characterization of mycorrhizal status in hosts can be a good indicator of symbiotic associations in inoculation experiments or in ecological research. The most common microscopic-based observation methods, such as (i) the gridline intersect method, (ii) the magnified intersections method and (iii) the five-class system of Trouvelot were tested to find the most simple, easily executable, effective and objective ones and their appropriate parameters for characterization of mycorrhizal status. In a pot experiment, white clover (Trifolium repens L.) host plant was inoculated with 6 (BEG144; syn. Rhizophagus intradices) in pumice substrate to monitor the AMF colonization properties during host growth. Eleven (seven classical and four new) colonization parameters were estimated by three researchers in twelve sampling times during plant growth. Variations among methods, observers, parallels, or individual plants were determined and analysed to select the most appropriate parameters and sampling times for monitoring. The comparability of the parameters of the three methods was also tested. As a result of the experiment classical parameters were selected for hyphal colonization: colonization frequency in the first stage or colonization density in the later period, and arbuscular richness of roots. A new parameter was recommended to determine vesicule and spore content of colonized roots at later stages of symbiosis.

Barley root growth and phosphorus bioavailability in soil treated with phosphate rocks.

The effects of five phosphate rocks (originating from Algeria, northern Florida, North Carolina, Senegal, and Morocco) with various phosphorus (P) solubilities on P bioavailability, root growth, and P uptake of spring barley crops were studied on an acidic sandy soil in microlysimeters, in a pot experiment and by dynamic simulation. Root length and P influx varied significantly, influenced by the P and calcium carbonate (CaCO3) content and reactivity of the P sources. Phosphate rock (PR) treatments enhanced root growth. The simulation results demonstrated the contribution of root hair formation and P mobilization by rhizosphere acidification in the increased acquisition efficiency of barley in PR‐treated soil.