纳米硒(SeNPs)缓解烟草幼苗铅胁迫和促生效应

Effect of Nano-selenium(SeNPs)in Alleviating Lead Stress and Promoting Growth of Tobacco Seedlings

【目的】旨在探究纳米硒(SeNPs)对铅(Pb)胁迫烟草幼苗的生长、抗逆性、铅吸收和转运的影响,以揭示SeNPs的促生效应、富硒和阻滞铅吸收及转运的机制。【方法】以普通烟草(Nicotianatabacum)为研究对象,通过盆栽实验设置不同处理,包括低剂量(100 mg/L)和高剂量(200 mg/L)Pb胁迫,无机硒(Na2SeO3)、SeNPs处理和空白对照组。测定各处理组烟草幼苗的生物量、光合生理参数、抗氧化酶活性、脂质过氧化产物含量以及相关基因表达水平,分析铅和硒在植物体内的含量和分布。【结果】与对照组相比,硒处理显著促进了烟草幼苗的生长和光合作用,SeNPs促生效应更显著。硒处理还增强了烟草幼苗的抗氧化酶(SOD、POD和APX等)活性和抗氧化物质(抗坏血酸和谷胱甘肽等)的含量,降低了脂质过氧化产物(H2O2和MDA)的积累。在铅胁迫条件下,硒处理可显著提高烟草幼苗中硒的含量,同时降低铅的吸收和转运率。【结论】纳米硒能显著提高植物生物量,保护光合系统,激活抗氧化系统,阻滞铅吸收和转运,促进植物硒富集和改善植物对铅胁迫的抗性。

【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.