Effects of Antimony and Arsenic on Antioxidant Enzyme Activities of Two Steppic Plant Species in an Old Antimony Mining Area

Abstract

The present work was undertaken to determine strategies and antioxidant enzyme activities involved in the adaptation of two wild steppic plants (Hedysarum pallidum Desf. and Lygeum spartum L.) to the toxic environment of the abandoned antimony mining area of Djebel Hamimat (Algeria). For this purpose, soils and plants were collected in different zones coinciding with a Sb and As concentrations gradient in the soil. Antimony (Sb) and arsenic (As) were analyzed by ICP-OES in the soils and the aboveground parts and roots of the plants. Malondialdehyde (MDA) and antioxidant enzyme activities were measured by spectrometry. Results show levels of Sb and As exceptionally high in most soil and plant samples. The two species accumulate differently Sb and As in their above and belowground parts. MDA levels, in the two parts of both species, increase significantly with increasing soil Sb and As concentrations, but they are significantly higher in H. pallidum than in L. spartum. The activities of antioxidant enzymes differ significantly according to the soil metalloid concentrations, the plant species considered and the plant part. Apart from superoxide dismutase (SOD) whose activity is, overall, higher in H. pallidum than in L. spartum, the activities of all the other enzymes studied (glutathione S-transferase (GST), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX)) are generally higher in L. spartum than in H. pallidum. For both species, APX and GST are overall more active in the upper parts than in the roots, while it is the reverse for SOD and CAT. POD is more active in the upper parts than in the roots of L. spartum and the reverse applies to H. pallidum. It appears that the two studied plant species use different tolerance strategies to protect themselves against elevated As and Sb concentrations.

Effects of antimony on redox activities and antioxidant defence systems in sunflower (Helianthus annuus L.) plants

“…Nonetheless, in neither organ was this increase in SOD activity sufficient to avoid overaccumulation of O 2 .- . These results are similar to those described by other workers [ 41 , 72 ] who have observed a strong increase in SOD activity in response to Sb toxicity, both in leaves and in roots. They are also consistent with those described by Feigl et al [ 39 ] in B .…”

“…The stress induced in plants by high concentrations of Sb leads to different responses depending on the species studied. Thus, in areas of Sb mines, preferential accumulation has been observed in roots [ 41 ]. But with other species, and even sometimes in other work, greater accumulation has been obtained in the leaves [ 6 , 11 , 19 ], and the process depends on the presence of other elements that may interfere with the absorption and transport of Sb, as is the case with Sb-mining soils and Dittrichia viscosa [ 6 , 11 ].…”

Antioxidative Enzyme Responses to Antimony Stress of Serratia marcescens – an Endophytic Bacteria of Hedysarum pallidum Roots

“…The sampling was carried out in March 2016 in the most contaminated station of the study area, which presents the following physicochemical properties as determined by previous authors [14]: 62000±4924 mg/kg of antimony (Sb), 2300±186 mg/kg of arsenic (As), 0.9±0.04% of organic matter (OM), 38.7±1.82% of CaCO 3 , 23.0 ± 4.9% of Clay, 16.3±1.02% of Silt, 53.7±3.22% of sand and a pH of 8.01±0.09.…”

“…The CAT activity was determined using the extinction coefficient 39.4 mM −1 cm −1 and specific activity was given as μM min -1 mg -1 proteins. Peroxidase (POD) activity (EC.1.11.1.7) was assayed by the method described by Benhamdi et al [14]. The amount of purpurogalin released after the reaction of pyrogallol with H 2 O 2 was measured at 420 nm.…”

“…In northeastern Algerian, a previous study revealed very high Sb levels in soils surrounding spoils of an old antimony mine (up to 81.446 mg/kg) involving modifications of the spontaneous vegetation and the survival of certain resistant plants [13]. This is the case of Hedysarum pallidum Desf., a Fabaceae, which concentrates up to 263 mg/kg of Sb in its upper parts and 183 mg/kg of this element in its underground parts [14]. According to these authors, the adaptation of this plant to high Sb concentrations resulted in the activation of its antioxidant enzymes such as CAT, SOD, APX and POD.…”