Oxidative Stress Induction by Lead in Leaves of Radish (Raphanus sativus) Seedlings

Abstract

Oxidative stress was induced by lead acetate (Pb) in Raphanus sativus seedlings grown in a hydroponic system using sand as substrate. Thirty day old acclimated seeds were treated for 7 days with five Pb levels (0 as control, 100, 200, 500 and 1000 mg l -1 ). Parameters such as growth, oxidative damage markers (lipid peroxidation, protein oxidation and hydrogen peroxide contents) and enzymatic activities of catalase (CAT) and peroxidase (POD) were investigated. Lead concentration in plant tissues increased with increasing of Pb levels. Shoot fresh weight, chlorophyll and carotenoid concentration were significantly decreased at 100 mg l -1 Pb. Lipid peroxidation, protein oxidation and H 2 O 2 levels were increased at 500 and 1000 mg l -1 Pb compared to control treatment, in shoots. Peroxidase activity showed a straight correlation with H 2 O 2 concentration, whereas CAT activity decreased only in shoots. These changes in enzymatic and non-enzymatic antioxidants showed that the Pb exposition had a significant disturbance on Raphanus sativus plantlets and affect the biochemical and physiological processes.

Ameliorative role of β-estradiol against lead-induced oxidative stressand genotoxic damage in germinating wheat seedlings

“…Increased GPX activity in lead-stressed roots might be due to the increase in the release of peroxidases localized in the cell walls (Lamhamdi et al, 2011) and can serve as an intrinsic defense tool to resist lead-induced oxidative damage (Yang et al, 2011). Enhancements in antioxidant enzyme activities indicate a more powerful defense capacity of plants against lead stress (Biteur et al, 2011). Our results also demonstrated that the antioxidative enzymes can play an important role against oxidative injury induced by lead toxicity.…”

“…Table 2 highlights the changes in these parameters in the roots of wheat affected by treatments of β-estradiol and lead stress. It was determined that lead stress caused a serious elevation in these parameters up to approximately two-fold that of the control groups in radish seedlings (Biteur et al, 2011). The elevation in these parameters clearly showed lead-induced oxidative damage.…”

“…Soluble protein contents were significantly increased by lead application. These increases might have resulted from de novo synthesis of stress proteins provoked by metal exposure (Biteur et al, 2011). In the absence of lead, exogenous β-estradiol application provided a marked increase in the soluble protein contents compared with the control seedlings.…”

“…The overall effect of the antioxidant system depends on the intracellular balance among antioxidant enzymes rather than a single component (Yang et al, 2010). Recently, it has also been reported that the activities of antioxidant enzymes increased in several higher plants under heavy metal stresses (Biteur et al, 2011;Yang et al, 2011). The data from the present study showed that activities of SOD, GPX, APX, and GR increased markedly in the roots of wheat under lead stress alone compared to control plants, whereas CAT activity was decreased severely by lead application.…”

Biochemical Adaptations in Zea mays Roots to Short-Term Pb2+ Exposure: ROS Generation and Metabolism

“…1d). The results are in concordance with that reported by Biteur et al (2011) who noticed carbonyl accumulation in radish exposed to 500-1000 mg L -1 of Pb 2? .…”