白花泡桐幼苗对铅胁迫的耐受机制与积累特性

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中图分类号：S766；Q945.78 文献标志码：A

Abstract：【Objective】To explore the tolerance mechanism and leadacumulationcharacteristicsof Paulownia fortunei seedlings underleadstres，-depthinvestigationofteintrinsicmechanismofulowniafortuneitoleraneofaymetals，soastoproide theoreticalsupportandscientificbasisforthedevelopmentandutilizationofheavymetalcontaminatedland.【Methods】60days Paulownia fortunei seedlings were taken as experimental materialsand five groups of Pb treatments were set up with different concentrations of Pb to simulate the stress environment，and measured the growth indexes，root parameters，antioxidant enzyme activities，MDAcontent，photosynthetic gasparameters，chlorophyll， Pb accumulation，enrichment coefficient and transport coefficient ofthsedlsuldsiedssesosesdl contentin Paulownia seedlingsacrossall treatment groupsdecreased significantly （P<0.05） ），whilethe limitingstomatalconductance （Ls） rose markedly;SODand CATactivities weakened concurrntlywhereas PODactivityremained stable.MDA content increased significantly.At a mass concentration of 800mg/L （P4），above-ground biomass，leaf area， plant height， stem diameter at ground level， andchloroplltetieasdLadtetdntctorinulodinggaualleadital accumulation in plant parts following the pattern：roots > leaves > stems.The transport coefficient exhibiteda zigzag decrease with increasing lead mass concentration.【Conclusion】Under Pb stress，the root uptake function of seedlings was weakened， resulting in growth restriction and significant reduction of several physiological indexes.However， under 800mg/L （P4） treatment， the growth and physiology of P.vesiculosus seedlings were promoted to different degrees.The seedlings accumulatedmostof the Pb in the root system toreducethelevelofmembranelipidperoxidationiducedyheavymetalstre，ndthussowedacertaindegreeoftolerancetothe stress induced by different concentrations of Pb

Keywords：Paulownia fortunei;Pb stres;physiologicalresponse;Pbaccumulation; translocationcoefficient

近年来，随着全球范围内工业活动的迅猛扩张和现代化进程的加速推进，土壤重金属污染问题愈发严峻，成为制约农业可持续发展和生态环境保护的重大障碍[1]，在这一系列重金属污染中，铅（Pb）污染因其来源广泛、毒性持久和生物累积性而尤为引人关注。（剩余20962字）