Cadmium tolerance in Thlaspi caerulescensII. Localization of cadmium in Thlaspi caerulescens

Distribution and concentration of cadmium in root tissue of Populus alba determined by scanning electron microscopy and energy-dispersive x-ray microanalysis

“…However, a specific analysis on vessel lumina associated with changes in wall strength in response to metal was not done, and possible effects of Cd on plant transport system cannot be ruled out. In plants subjected to long-term treat ment with Cd, alterations of the root struc ture might also influence redistribution and accumulation of the metal in different root tissues and/or cell compartments (Wójcik et al 2005). …”

“…However, compared with other important ions (e.g., Ca, showing a rather diffuse alloc ation), the distribution of Cd within the root (similar to that of K) was preferentially loc alized in the surroundings of central cylin der. Many studies have shown that the main site of Cd accumulation in roots is the apo plast, particularly cell walls (Wójcik et al 2005). Khan et al (1984) and LozanoRodríguez et al (1997) found that in maize roots the metal was mainly detected in cell walls of cortex parenchyma, endodermis and pericycle, while much smaller amounts were found in protoplasts.…”

“…Some authors suggest that in roots, the capacity to bind Cd in the cell wall has a protective action against the deleterious effect of Cd by redu cing the amounts of cytosolic Cd (LozanoRodríguez et al 1997, Ramos et al 2002, Zornoza et al 2002. Again, Wójcik et al (2005) and Vögeli-Lange & Wagner (1990) suggest that the cell wall plays a minor role in Cd retention in leaves, and the main mechanisms of Cd detoxification are located inside cells, in vacuoles. Cadmium may in duce synthesis of metal binding organic sub stances for metal detoxification in the cyto plasm (Reese & Wagner 1987, Weigel & Jäger 1980.…”

“…There are different methods for determining ele ments distribution in plant tissues such as histochemical (Vázquez et al 1992b, Seregin & Ivanov 1997, cell fractionation (LozanoRodríguez et al 1997), x-ray microanalysis (Khan et al 1984, Vázquez et al 1992a, Vázquez et al 1992b, particle-induced x-ray emission (micro-PIXE - Ager et al 2002) or nuclear micro-probe technique (NMP -Ager et al 2003). Although not always useful at very low metal concentrations, x-ray mi croanalysis provides specific signals com pared to other methods (Wójcik et al 2005(Wójcik et al et al 2005. In the present work we used x-ray microanalysis to determine tissue localiza tion and concentration of Cd in root tips of Populus alba clones (6K3 and 14P11).…”

Antioxidant enzymes and proteins of wetland plants: Their relation to Pb tolerance and accumulation

“…In the present study, our results showed that those species with higher Pb tolerance were able to maintain higher levels of POD activity under higher Pb stress. POD also participates in lignin biosynthesis (Podazza et al 2012), an important tolerance mechanism protecting the protoplast from toxic effects of heavy metals (Wojcik et al 2005;Adhikari et al 2010). It suggests that the wetland species with higher POD activity may be more efficient in avoiding damage from Pb.…”