Arsenic toxicity in Acacia mangium willd. and mimosa Caesalpiniaefolia benth. seedlings

Abstract

SUMMARYAcacia mangium and Mimosa caesalpiniaefolia are fast-growing woody fabaceous species that might be suitable for phytoremediation of arsenic (As)-contaminated sites. To date, few studies on their tolerance to As toxicity have been published. Therefore, this study assessed As toxicity symptoms in A. mangium and M. caesalpiniaefolia seedlings under As stress in a greenhouse. Seedlings of Acacia mangium and M. caesalpiniaefolia were grown for 120 d in an Oxisol-sand mixture with 0, 50, 100, 200, and 400 mg kg -1 As, in four replications in four randomized blocks. The plants were assessed for visible toxicity symptoms, dry matter production, shoot/root ratio, root anatomy and As uptake. Analyses of variance and regression showed that the growth of A. mangium and M. caesalpiniaefolia was severely hindered by As, with a reduction in dry matter production of more than 80 % at the highest As rate. The root/shoot ratio increased with increasing As rates. At a rate of 400 mg kg -1 As, whitish chlorosis appeared on Mimosa caesalpiniaefolia seedlings. The root anatomy of both species was altered, resulting in cell collapse, death of root buds and accumulation of phenolic compounds. Arsenic concentration was several times greater in roots than in shoots, with more than 150 and 350 mg kg -1 in M. caesalpiniaefolia and A. mangium roots, respectively. These species could be suitable for phytostabilization of As-contaminated sites, but growth-stimulating measures should be used.Index terms: arsenate, heavy metals, phytoremediation, root anatomy, soil contamination.(

Phytoremediation of Arsenic in Mine Wastes by Acacia mangium

“…However, no leaves were seen on plants grown on 1,000 and 1,500 mg kg −1 of arsenic indicating the phytotoxicity effect of high arsenic concentrations toward Acacia mangium . Previous work by Cipriani et al (2013) observed a phytotoxicity effect as the soil concentration of arsenic increased to 400 mg kg −1 . The difference could be due to the arsenic compound used in that work, which was arsenic trioxide (As 2 O 3 ) instead of sodium arsenate (Na 3 AsO 4 ) used in this study.…”

“…Acacia has a relatively high biomass production which also allows Acacia to be used for bioenergy production (Gasol et al, 2010), thus adding an economical option for this species to be used post‐phytoremediation. Previous work by Cipriani et al (2013) found that Acacia mangium could survive on soil dosed with up to 400 mg kg −1 of arsenic with higher concentrations of arsenic found in the roots compared with shoots. However, to date, no work has been done to investigate the uptake and survivability of Acacia mangium grown on mine wastes containing high concentrations of arsenic.…”

Enhancement of phytoremediation efficiency of Acacia mangium using earthworms in metal-contaminated soil in Bonoua, Ivory Coast

“…types and quantities of organic acids into the rhizosphere, which may enhance the mobility of metals and their uptake by roots, explaining the immobilization of Cr, Ni and Pb in plant biomass. In addition, the higher content of Cr and Pb in RS and Ni in DS than in plant biomass could be related to the physiological character of Acacia spp., which here seems to exclude a metal in its shoot tissue (Kabas et al, 2017;Majid et al, 2012;Mohd et al, 2013;Cipriani et al, 2013).…”

“…This emphasizes that Acacia may possess metal exclusion strategy, which probably depend to the nature of the metal. The bioconcentration factors (BCF) ([metal]plant biomass/[metal]soil) were BCF <0.1 under CNi and CI treatments (Table 2), which were indicated that Acacia are not hyperaccumulator plant as demonstrated by Cipriani et al (2013). The findings did not differ from those of various studies indicating that Acacia is able to tolerate and uptake heavy metal in its tissues and therefore could be suitable for phytostabilization of metalcontaminated sites (Majid et al, 2012;Mohd et al, 2013).…”

Arsenic: behavior in the environment, plant uptake mechanisms and human health risks

“…Although the contaminants are not removed from the site, phytostabilization allows reducing the risk of erosion and the leaching of pollutants, preventing groundwater phytotoxicity Ma, 2013;De Oliveira et al, 2014). On the other hand, species unable to tolerate or hyperaccumulate As, such as Acácia mangium and Mimosa caesalpiniaefolia (Cipriani et al, 2013), may experience phytotoxicity, affecting their development and causing death. In rice, As uptake occurs in the form of arsenite as well as arsenate, depending on the cultivation conditions: arsenite prevails in rice crops grown in flooded areas, while arsenate prevails under aerobic conditions.…”