Accumulation of Four Metals in Tissues of Corchorus olitorius and Possible Mechanisms of Their Tolerance

Abstract

Corchorus olitorius plants treated by 5 µg cm -3 of Cd, Pb, Al or Cu in hydroponic culture accumulated in leaves 190, 150, 350 and 325 µg g -1 (d.m.) of these metals, respectively, after 6 d of exposure. Exposure of Corchorus plants to tested metals resulted in a sharp rise in content of amino acids in leaf tissues, however the magnitude of accumulation was different from one metal to another. Presence of sulphur in the growth medium significantly increased uptake of Cd and Pb and cysteine (cyst) was more effective than K 2 SO 4 . Similarly, addition of salicylic acid (SA) in the growth medium significantly enhanced the ability of Corchorus plants to accumulate all these metals. Growth of Corchorus plants was significantly reduced by treatment with any of the four metals except Cu and added cyst, K 2 SO 4 or SA alleviated the growth retarding effect of metals.

The influence of duckweed species diversity on ecophysiological tolerance to copper exposure

“…Excessive copper accumulation in plant tissues can affect nitrogen metabolism with reduction of total nitrogen (Llorens et al, 2000;Mazen, 2004). Our results agreed with their reports and also revealed that the protein content clearly declined with high copper accumulation (Table 1).…”

Lead-induced oxidative stress and metabolic alterations in Cassia angustifolia Vahl.

“…Thus, membrane lipid peroxidation is an indicator of oxidative damage resulting in the loss of cell membrane lipids caused by free radicals and hydroperoxides (Thompson 1988, Smirnoff 1993. Ultimately, a reduction in biomass is caused by heavy metal stress (Mazen 2004) and also a decreased yield of metabolites as also observed in this study. Accumulation of TBARS, the decomposition product of polyunsaturated fatty acids of biomembranes, certain amino acids and DNA, in tissues of Pb-treated plants indicates that Pb is capable of inducing oxidative stress in the plant system and accelerates the senescence rate.…”

“…There are only few reports about the effect of abiotic stresses on the functioning of secondary metabolism, particularly on the concentration of secondary metabolites of therapeutic properties (Singh et al 1999, Arshi et al 2002, 2004. Moreover, the effects of heavy metals and oxidative stress and their interactions on secondary metabolism are yet to be understood.…”

Phytoremediation Using Algae and Macrophytes: I

“…Several heavy metal tolerance mechanisms within the plants have been suggested by various researchers (Mazen 2004 ;Hall 2002 ) including: (1) synthesis of metal-binding compounds such as amino acids, citric acid, malic acid, and phytochelatins (PCs) (Reilly 1972 ;Thurman and Rankin 1982 ;Brookes et al 1981 ;Grill et al 1985, Rtiegsegger and Brunold 1992Cobbett and Goldsbrough 2002 ;Hall 2002 ); (2) alterations of membrane structures (De Vos et al 1988 ); (3) complex formation in vacuoles (Fernando and Fernando 1994 ); and (4) synthesis of stress metabolites including proteins (Neumann et al 1994 ). It is also evident that of the abovementioned mechanisms more than one mechanism may be working together in the same species (Hall 2002 ).…”