Responses induced by high concentration of cadmium in Phragmites australis roots

Abstract

Cadmium is an important environmental pollutant with high toxicity to plants. We report the effects of high-dose Cd (100 micro M for 21 days) on the root apparatus of Phragmites australis plants, which are characterized by elevated water detoxification capacity and widely used in phytoremediation programmes. The examination of root sections by light and electron microscopy failed to reveal any significant cadmium-induced structural or ultra-structural modifications. However, histochemical localization of Cd disclosed accumulation of the metal in the parenchyma cells below the exodermis. Phytochelatins (PC) are thiol-rich peptides whose synthesis is induced by a range of metals. Our results indicate that total PC production increases after exposure to Cd, which suggests a pivotal role for phytochelatins in the sequestration of metal. Cd treatment also induced lignin deposition and marked stimulation of root antioxidant systems, suggesting that, because of its ability to adopt different strategies against the harmful effects of cadmium, Phragmites australis is a plant with high detoxification potential.

Passive warming reduces stress and shifts reproductive effort in the Antarctic moss,Polytrichastrum alpinum

“…TBARS were identified by visible spectrophotometry as detailed in previous studies (Ederli et al, 2004), with results expressed in terms of malondialdehyde (MDA) equivalents (Kwon and Watts, 1964;Ederli et al, 2004).…”

Peroxidase activity against guaiacol, NADH, chlorogenic acid, ferulic acid and coniferyl alcohol in root tips of Lotus japonicus and L. corniculatus grown under low pH and aluminium stress

“…On the other hand, spatially localized changes in CW modification such as crosslinking or lignification are involved in the inhibition of root growth but may facilitate root acclimation to drying or toxic environment (Fan et al 2006). CW lignification and suberization of epidermis and exodermis in the RT of Phragmites australis are interpreted as a defence reaction that limits the entry of toxic metals into the roots (Ederli et al 2004). It has been reported that the two times higher lignin deposition was detected into the root endodermis in hyperaccumulator Thlaspi caerulescens in comparison to Arabidopsis thaliana (van de Mortel et al 2006).…”

Lipid peroxidation in plant cells, its physiological role and changes under heavy metal stress

“…Especially, under Cu excess, a metal concentration-dependent increase in MDA+HAE content was observed (Skórzyñska-Polit et al 2004b) but in Phaseolus coccineus plants treated with Cd this kind of lipid oxygenation was limited (Skórzyñska-Polit and Krupa 2005). Similarly, no peroxidation was noticed in Cd-exposed plants and hairy roots of Daucus carota (Sanita di Toppi et al 1999) and in roots of Phragmites australis (Ederli et al 2004).…”