Effect of Nano-selenium(SeNPs)in Alleviating Lead Stress and Promoting Growth of Tobacco Seedlings
[Objective]This study is to explore effects of nano-selenium(SeNPs)on growth and stress resistance of tobacco seedlings under lead(Pb)stress,as well as Pb absorption and translocation,aiming to reveal the mechanisms of SeNPs-mediated growth promotion,Se enrichment,and inhibition of Pb uptake and transfer in plants.[Method]Common tobacco(Nicotiana tabacum)was selected as the test crops.Various treatments were designed and used in a series of pot experiments,including low(100 mg/L)and high(200 mg/L)doses of Pb stresses,inorganic Se(Na2SeO3)and SeNPs trteatments as well as blank controls.Physiological and biochemical indexes of tobacco seedlings were quantitatively measured,including biomass,photosynthetic physiological parameters,antioxidant enzyme activities,lipid peroxidation product contents,and the related gene expression levels in tobacco seedling.The contents and distribution of Se and Pb were also examined in both aboveground and underground organs.[Result]Compared with the control group,Se treatments significantly promoted the growth and photosynthesis of tobacco seedlings,with SeNPs showing more significant growth-promoting effect.Se treatments also enhanced the antioxidant enzyme(SOD,CAT,POD and APX)activities and accumulation of lipid peroxidation products(proline,ascorbic acid and glutathione),followed by reducing accumulation of lipid peroxidation products(proline,ascorbic acid and glutathione)in tobacco seedlings.Under Pb stress conditions,Se treatments significantly increased the selenium content in tobacco seedlings,whereas the Pb absorption and transport rate from underground to aboveground parts were largely reduced in tobacco seedlings.[Conclusion]SeNPs demonstrates signicantly growth-promoting effects,including increasing plant biomass,protecting photosynthesis system,activating antioxidant system,blocking lead absorption and transport,facilitating selenium enrichment and improving plant resistance to lead stress.
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