33 research outputs found
Is callose a barrier for lead ions entering Lemna minor L. root cells?
Plants have developed a range of strategies for resisting environmental stresses. One of the most common is the synthesis and deposition of callose, which functions as a barrier against stress factor penetration. The aim of our study was to examine whether callose forms an efficient barrier against Pb penetration in the roots of Lemna minor L. exposed to this metal. The obtained results showed that Pb induced callose synthesis in L. minor roots, but it was not deposited regularly in all tissues and cells. Callose occurred mainly in the protoderm and in the centre of the root tip (procambial central cylinder). Moreover, continuous callose bands, which could form an efficient barrier for Pb penetration, were formed only in the newly formed and anticlinal cell walls (CWs); while in other CWs, callose formed only small clusters or incomplete bands. Such an arrangement of callose within root CWs inefficiently protected the protoplast from Pb penetration. As a result, Pb was commonly present inside the root cells. In the light of the results, the barrier role of callose against metal ion penetration appears to be less obvious than previously believed. It was indicated that induction of callose synthesis is not enough for a successful blockade of the stress factor penetration. Furthermore, it would appear that the pattern of callose distribution has an important role in this defence strategy
Sites for the selective hydrogenation of ethyne to ethene on supported NiO/Au catalysts
Effects of Transplanting Time on 15-Nitrogen Utilization and Industrial Quality of Flue-Cured Tobacco
Hydrogen Adsorption on PlatinumâGold Bimetallic Nanoparticles: A Density Functional Theory Study
Gold Stabilized by Nanostructured Ceria Supports: Nature of the Active Sites and Catalytic Performance
The structure and development of polyphenolic parenchyma cells in Norway spruce (Picea abies) bark
Effects of UV-C and UV-B on cytomorphology and water permeability of inner epidermal cells of Allium cepa
Electrocatalytic hydrogen redox chemistry on gold nanoparticles
Electrocatalytic proton reduction leading to the formation of adsorbed molecular hydrogen on gold nanoparticles of 1-3 and 14-16 nm diameter stabilized by 1-mercapto-undecane-11-tetra(ethyleneglycol) has been demonstrated by cyclic voltammetry using a hanging mercury drop electrode. The nanoparticles were adsorbed to the electrode from aqueous dispersion and formed robust surface layers transferrable to fresh base electrolyte solutions. Unique electrocatalytic proton redox chemistry was observed that has no comparable counterpart in the electrochemistry of bulk gold electrodes. Depending on size, the nanoparticles have a discrete number of electrocatalytically active sites for the two-electron/two-proton reduction process. The adsorbed hydrogen formed is oxidized with the reverse potential sweep. These findings represent a new example of qualitative different behavior of nanoparticles in comparison with the corresponding bulk material.Fil: Brust, Mathias. University of Liverpool; Reino UnidoFil: Gordillo, Gabriel Jorge. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de QuĂmica InorgĂĄnica, AnalĂtica y QuĂmica FĂsica; Argentin