Lead uptake, localization and changes in cell ultrastructure ofFunaria hygrometrica protonemata

Abstract

The main sites of lead entering the protonemata were spores with broken cell walls and apical cells of protonemata. The lead ions could enter the symplast probably by endocytosis but we can not exclude diffusion as the way of entering. Lead deposits inside a protoplast were observed after 2 h of lead application. After 12 h, Pb deposits were commonly present in all cell structures surrounded by a membrane. Some disturbances in ultrastructure of organelles were found after 8 h. The most frequent were: change of endoplasmatic reticulum configuration from linear to concentric one in many cases surrounding other organelles (e.g. mitochondria) and large and numerous plastoglobuli in chloroplasts. Longer treatment of protonemata with lead (24 h or 48 h) caused degeneration of organeUes and even death of the cell.

Antifungal activity of thyme oil againstGeotrichum citri-aurantii in vitroandin vivo

“…However, Maisnier-Patin andRichard (1996) reported that exposure of Listeria innocua to nisin concentrations of 500 and 4000 IU ml )1 induced cell wall thickening as well as irregularities. Krzesłowska and Woźny (1996) founded that 48 h-treatment 4 lmol l )1 PbCl 2 resulted in cell wall thickening at the tip of the apical cell.…”

The cell wall in plant cell response to trace metals: polysaccharide remodeling and its role in defense strategy

“…CW thickenings appeared at the tip of apical cells (Fig. 2d, f), one of the main sites of Pb uptake (Krzesłowska and Woźny 1996). It was striking that the nature of the F. hygrometrica thickenings markedly differed from that of the CW in unexposed plants.…”

“…Hence, TMs, already present within the endomembrane system, can be easily removed from the protoplast by the vesicular secretion pathway and sequestered in the CW (e.g., Malone et al 1974;Woźny et al 1982;Ksią _ zek et al 1984;Hubner et al 1985;Krzesłowska and Woźny 1996;Wierzbicka et al 2007;Meyers et al 2009). Results of recent studies, concerning the uptake and sequestration of Al in A. thaliana (Illéš et al 2006) and Pb in F. hygrometrica (Krzesłowska et al 2010) have provided more compelling evidence for this phenomenon.…”

“…3. ; e.g., Malone et al 1974;Woźny et al 1982;Ksią _ zek et al 1984;Hubner et al 1985;Krzesłowska and Woźny 1996;Illéš et al 2006;Wierzbicka et al 2007;Meyers et al 2009;Krzesłowska et al 2010).…”

“…TMs are categorized into those that are essential for many physiological processes, e.g., Cu, Zn and Fe, the excess as well as deficiency of which can cause harmful effects in plant cells, and nonessential ones, such as Pb, Cd, Al and Hg, which may be toxic even in relatively low concentrations (for review, e.g., Hall 2002;Patra et al 2004;Appenroth 2010). Trace metals can enter the plant cell by diffusion through the plasma membrane (PM) (Krzesłowska et al 2009b), via endocytosis (e.g., Malone et al 1974;Woźny et al 1982;Ksią _ zek et al 1984;Hubner et al 1985;Krzesłowska and Woźny 1996;Illéš et al 2006;Wierzbicka et al 2007;Krzesłowska et al 2009a;Meyers et al 2009), and due to the activity of special metal transporters that function in the PM. The latter aspect has been the subject of a great deal of attention and many review papers are available (e.g., Colangelo and Guerinot 2006;Krämer et al 2007; Krzesłowska et al 2009b;Pilon et al 2009;Puig and Penarrubia 2009).…”