30th August - 1st September, 2017: XII. Congress of the Hungarian Society for Plant Biology, Szeged, Hungary

[Z. Klencsar]

The Hungarian Society for Plant Biology held its XII. congress during the days of August 30 – September 1, 2017, at the Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary. On the conference Ferenc Fodor, head of the Department of Plant Physiology and Molecular Plant Biology, ELTE Eötvös Loránd University, Budapest, Hungary, presented a lecture about recent findings related to the possible use of iron, manganese and zinc bearing nanoparticles in the alleviation of micronutrient defficiencies common on alkaline soils.

Manufactured nanomaterials: new iron based fertilizers or potentially toxic agents?

Fruzsina Pankaczi 1, Zsuzsanna Farkas 1, Brigitta Müller 1, Krisztina Kovács 2, Zoltán Klencsár 3, Zoltán May 4, Zoltán Sándor 4, Ervin Gy. Szabó 4, Eszter Bódis 4, László Szabó 4, Ernő Kuzmann 2, Zoltán Homonnay 2, Gyula Tolnai 5, Ádám Solti 1, Ferenc Fodor 1

1 Department of Plant Physiology and Molecular Plant Biology, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
2 Department of Analytical Chemistry, Institute of Chemistry, ELTE Eötvös Loránd University, Budapest, Hungary
3 Centre for Energy Research, Hungarian Academy of Sciences, Budapest, Hungary
4 Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
5 168 Fehérvári street, 1116 Budapest, Hungary

Micronutrient deficiency is one of the major agricultural problems worldwide. It may be caused by the soil characteristics such as high pH, organic matter horizon, liming etc. Fe, Mn and Zn are essential heavy metals required by plants in the highest concentration among micronutrients. Fertilizers such as stable Fe-chelates preserve solubility and availability for plant uptake during the growth period but most commercial chelates are not biodegradable. A cheap alternative may be the application of manufactured nanomaterials. Newly designed nanomaterials have been characterised and then applied in hydroponic cultures to cucumber plants in a wide range of concentration. Nanoferrihydrite colloid suspension of 5-8 nm particle size and Mn-Zn-ferrite suspension of 3-5 nm applied in 0.01-0.02 mM concentration and at slightly acidic pH proved to be a good source of Fe, Mn and Zn in various experimental conditions. Mn-Zn-ferrite has also been tested at pH 7 and iron deficient cucumber plants showed a significant recovery after 3 days of application. Ferric chelate reductase assays showed that it is not the normal reduction-based uptake pathway that plays a role in the utilization of these nanoparticles. Elevated concentrations of the nanomaterials at the milimolar range as compared to similar concentrations of micronutrient salts proved to be less toxic. NanoFeCo (ca. 1:1), an insoluble powder has been tested only in 0.1-1 mM concentration. Cucumber plants showed a significant growth inhibition and marked chlorosis. ICP measurements revealed Co accumulation and induced Fe deficiency chlorosis.