ROLE OF CHELATORS IN ALLEVIATING OXIDATIVE DAMAGE IN RADISH SHOOT SUBJECTED TO CADMIUM STRESS | ||||
| Journal of Plant Production | ||||
| Article 7, Volume 2, Issue 10, October 2011, Page 1359-1378 PDF (766.72 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jpp.2011.85663 | ||||
 View on SCiNiTO | ||||
| Author | ||||
S. Farouk  
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| Agric. Botany Dept., Fac. Agric., Mansoura University, Mansoura, Egypt. | ||||
| Abstract | ||||
| Radish (Raphanus sativus L.) plants were grown with 0, 100 and 150 mg/kg soil cadmium chloride and treated with 100 or 200 mg/l chitosan or humic acid as soil additives to study the responses of leaf area, metabolite accumulation, oxidative stress and enzymatic and non-enzymatic antioxidant physiological processes to cadmium or chelators and to show the influence of chelating application on the alleviation of cadmium chloride induced adverse effects. Results revealed that cadmium stress caused reduction in leaf area, parallel to increased hydrogen peroxide levels, lipid peroxidation and electrolyte leakage in shoot tissues which were significantly reversed by either humic acid or chitosan. The antioxygenic enzymes viz. catalase and peroxidase were significantly decreased due to increasing cadmium concentration. Either humic acid or chitosan induced enzymes activities in shoot tissues of cadmium stressed plants. Proline, ascorbic acid, soluble sugars and total phenol significantly increased due to cadmium chloride or chelators as well as their combinations. Anatomically, either chitosan or humic acid increased the diameter of radish root due to an increase in the thickness of cortex and diameter of vascular cylinder as well as diameter of metaxylem vessel, the thickness of radish leaf blade due to the increase in the thickness of mesophyll tissue as well as thickness of both lower and upper epidermal cells. In addition, the thickness of leaf blade through midrib region was also increased, due to the increase in the midrib vascular bundle thickness, as well as the size of the medvien vascular bundle, area of xylem and phloem tissues. Cadmium stress decreased all anatomical characteristics of root and shoot. It appears clearly that both chelators application partially overcame the depression effect of high cadmium level on the radish root and leaf structure. This finding suggests that both chelators, in particular, chitosan might be activating antioxygenic enzymes and elevating antioxidants thereby controlling free radical generation, hence preventing membrane peroxidation and denaturation of biomolecules resulting into improved leaf area of radish plant grown under cadmium stress. | ||||
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