Lead Accumulation Potential inAcacia victoria

Abstract

To assess the potential of Pb+2 accumulation in different parts of Acacia victoria, one year old A. victoria seedlings were exposed to Pb2+(NO3)2 in 5 different concentrations: 0, 50, 250, 500 and 1000 (mg Pb2+ L(-1)) for 45 days. Subsequently, Pb2+ uptake was quantified in roots, shoots and leaves of the seedlings by Atomic Absorption Spectroscopy (AAS). In addition, some physiological parameters such as biomass production, shoots and roots length, plant appearance, tissue concentrations and chlorophyll content were examined. Tissue concentrations increased as Pb2+ concentration increased for A. victoria. The visible toxicity symptoms (chlorosis and necrosis) appeared only to the highest concentration (1000 mg Pb2+ L(-1)), resulting in photosynthesis decrease, plant height, root length and dry biomass reduction. Almost 70% (up to 3580 mg Kg(-1) of dry tissue) from the Pb2+ was accumulated in the entire plant tissues was retained in the roots in the seedlings exposed to 1000 mg Pb2+ L(-1). The seedlings accumulated between 403 to 913 mg Kg(-1) of Pb2+ in shoots and 286 to 650 mg Kg(-1) of Pb2+ in leaves at different treatments. Bioconcentration and translocation factors were determined 5.14 and 0.255, respectively. The results show that A. victoria is suitable for lead-phytostabilization in Pb(2+) -contaminated soil.

Differential expression of zinc accumulation during two growing seasons of Acacia victoriae

“…Bioconcentration factor (BCF) was defined as the ratio of Zn concentrations in plant tissues (roots, shoots and leafs) ([Zn] plant ) to Zn concentration in the soil medium ([Zn] medium ) (Maldonado-Magana et al 2011;Mahdavi et al 2014). That is a dimensionless number representing how much of a chemical is in a tissue relevant to how much of that chemical exists in the medium.…”

“…The translocation factor (TF) indicates the ability of plant to translocate heavy metals from roots to the harvestable aerial part (Waranusantigul et al 2008;Mahdavi et al 2014). It was calculated on a dry weight basis by dividing the metal concentration in shoots and leafs by the metal concentration in roots (Waranusantigul et al 2008;Mahdavi et al 2014)…”

“…The dried samples (roots, shoots, and leafs) were digested in a microwave oven at high temperature (up to 235°C) using 8 mL of HNO 3 (65 %), 2 mL of H 2 SO 4 , 1 mL of HClO 4 (70 %) (Moreira et al 2011;Mahdavi et al 2014). Zn concentrations were determined by an Atomic Absorption Spectrophotometer (AAS) (CTA-2000 AAS, Chem Tech Analytical) and the values were expressed as mg per Kg dry weight.…”

“…The root length can be used as an important TI (Piechalak et al 2002). TI was calculated as follows (MaldonadoMagana et al 2011;Mahdavi et al 2014).…”

“…Then, 1 mL of the surface solution was removed and adjusted with 4 mL 80 % acetone. After that, the optical density of the solution was measured by PD-303 UV spectrophotometer at different wavelengths i.e., 645, 663 nm and chlorophyll content was calculated using relevant formulae (Strain and Svec 1966;Mahdavi et al 2014).…”