Physiology and Biochemistry of Lead Accumulation in Sesbania Drummondii
type: CreativeWork
description: This thesis presents the results of three different studies conducted to elucidate the physiology and biochemistry of lead tolerance of Sesbania drummondii. These studies were conducted to determine: 1) the presence of an antioxidant mechanism in S. drummondii to counteract oxidative stress resulting from Pb exposure, 2) the extent of Pb tolerance of S. drummondii seedlings grown in the presence of Pb and synthetic chelators in soil and 3) the expression of antioxidant enzymes in S. drummondii seedlings exposed to Pb and synthetic chelators in aqueous media. In the first study, Sesbania drummondii plants were grown in soil containing 0-10 g/kg Pb(N03)2 for 0-4 weeks, and were assessed for photosynthetic activity, growth, and Pb accumulation at each harvest. It was observed that S. drummondii seedlings were able to tolerate up to 10 g/kg Pb in soil with the only visible symptom of Pb toxicity being stunted growth. Photosynthetic efficiency of these plants remained unaffected. Plants were also grown in soil containing 7.5 g/kg Pb(N03)2in combination with chelators such as EDTA, DTPA, HEDTA, NTA and citric acid at concentrations of 0, 1.25, 2.5, 5 and 10 mmol/kg. Plants suffered little or no effect on growth and photosynthetic activity. The greatest amount of plant growth was displayed by plants grown in the presence of 7.5 g/kg Pb(N03)2and 10 mmol/kg citric acid. Accumulation of Pb in roots and shoots was also determined. This study provides evidence for the efficacy of chelate application in combination with a large-biomass Pb accumulator plant in a phytoextraction strategy. In the second set of experiments, seedlings of Sesbania drummondii were exposed to 500 mg/L Pb(NOs)2 in presence and absence of EDTA, DTPA and HEDTA for 7-28 days. Plants were assayed for metal-induced stress, which was indicated by increased activities of antioxidant enzymes such as ascorbate peroxidase (APX), guaiacol peroxidase (GPX), catalase (CAT), and superoxide dismutase (SOD). Growth in t…
abstract: This thesis presents the results of three different studies conducted to elucidate the physiology and biochemistry of lead tolerance of Sesbania drummondii. These studies were conducted to determine: 1) the presence of an antioxidant mechanism in S. drummondii to counteract oxidative stress resulting from Pb exposure, 2) the extent of Pb tolerance of S. drummondii seedlings grown in the presence of Pb and synthetic chelators in soil and 3) the expression of antioxidant enzymes in S. drummondii seedlings exposed to Pb and synthetic chelators in aqueous media. In the first study, Sesbania drummondii plants were grown in soil containing 0-10 g/kg Pb(N03)2 for 0-4 weeks, and were assessed for photosynthetic activity, growth, and Pb accumulation at each harvest. It was observed that S. drummondii seedlings were able to tolerate up to 10 g/kg Pb in soil with the only visible symptom of Pb toxicity being stunted growth. Photosynthetic efficiency of these plants remained unaffected. Plants were also grown in soil containing 7.5 g/kg Pb(N03)2in combination with chelators such as EDTA, DTPA, HEDTA, NTA and citric acid at concentrations of 0, 1.25, 2.5, 5 and 10 mmol/kg. Plants suffered little or no effect on growth and photosynthetic activity. The greatest amount of plant growth was displayed by plants grown in the presence of 7.5 g/kg Pb(N03)2and 10 mmol/kg citric acid. Accumulation of Pb in roots and shoots was also determined. This study provides evidence for the efficacy of chelate application in combination with a large-biomass Pb accumulator plant in a phytoextraction strategy. In the second set of experiments, seedlings of Sesbania drummondii were exposed to 500 mg/L Pb(NOs)2 in presence and absence of EDTA, DTPA and HEDTA for 7-28 days. Plants were assayed for metal-induced stress, which was indicated by increased activities of antioxidant enzymes such as ascorbate peroxidase (APX), guaiacol peroxidase (GPX), catalase (CAT), and superoxide dismutase (SOD). Growth in t…
author: Ruley, Adam
keywords: Medical Sciences
date published: 2004-08-01T07:00:00Z
date modified: 2026-07-24T06:07:28Z
provider: Western Kentucky University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Western Kentucky University