Effect of Nitric Oxide on Lead Toxicity Stress in Wheat Triticum Aestivum L Seedlings

Abstract

The present study was carried out on wheat (Triticum aestivum L.) seedling to newlinedetermine effect of exogenous lead (Pb) on their growth and antioxidative defence newlinesystem and to explore the role of sodium nitroprusside in ameliorating effects for lead newlinetoxicity. For this investigation, PBW 343 seeds of wheat genotype were pre-treated newlinewith varying concentrations of Pb, SNP and Pb + SNP and growth data was taken at 7 newlinedays of treatments. In comparison to control seedlings the application of 100 and 500 newlineµM of Pb had growth inhibitory effects in wheat seedlings and decreased germination newlinepercentage, shoot and root length and also reduced fresh and dry weight. The results newlineof experiment showed reduction in photosynthesis pigments such as Chl a, Chl b ,total newlinechlorophyll and carotenoid content in germinated wheat seedlings at higher newlineconcentration of Pb. The enhancement of hydrogen peroxide, malondialdehyde and newlineproline content in shoot and roots tissues were recorded after Pb treatment. Treatment newlinewith 500 µM Pb showed reduced CAT and POD enzymes activities whereas newlineincreased SOD activity in shoot and root of wheat seedling. newlineExogenous application of 100 µM SNP had growth promoting effects in wheat newlineseedlings while; higher concentration of SNP inhibited seedling growth. Exogenous newlineapplication of 100 µM SNP increases photosynthetic pigments content in wheat (Chl a, newlineChl b, total chlorophyll and carotenoid). Supplemented with 100 µM SNP enhances newlineactivity of H 2 O 2 scavenging enzymes. A reduction in the activities of antioxidative newlineenzymes was observed at 100 µM SNP along with reduction in hydrogen peroxide, newlinemalondialdehyde and proline contents. Wheat seedlings pre-treated with 100 µM SNP newlineshow up-regulated CAT and POD activities which may a cause for lower H 2 O 2 , MDA newlineand proline content. SNP at lower concentration enhances protein content in wheat newlinevariety PBW 343. newline