铜对苋菜幼苗光合参数和活性氧代谢影响

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1、5期柯世省：铜对苋菜幼苗光合参数和活性氧代谢的影响1325铜对苋菜幼苗光合参数和活性氧代谢的影响柯世省（台州学院生命科学学院，浙江临海317000）摘要：【目的】明确铜毒影响苋菜（Amaranthustricolor）幼苗光合作用和活性氧代谢的生理机制。【方法】采用土培试验测定了不同水平铜处理下苋菜幼苗生长、光合作用、矿质元素吸收和活性氧代谢的相关指标。【结果】2.0～4.0mmol·kg-1铜处理下植株干重降至无铜处理（对照）的91%～73%，净光合速率和气孔导度均明显减小，但胞间CO2浓度并没发生显著变化，最大光化学效率的变化比实际量子效率小得多，这暗示着光合作用暗反应对ATP和NA

2、DH需求减少使光化学下调。此外，叶片光合色素、水分和矿质元素Fe、K和Mg含量均明显降低，Cu含量明显升高。2.0～4.0mmol·kg-1铜处理显著增加叶片超氧化物歧化酶、过氧化物酶活性和脯氨酸含量，降低过氧化氢酶、抗坏血酸过氧化物酶活性及类胡萝卜素、还原型谷胱甘肽和抗坏血酸含量，并伴随丙二醛含量和细胞电解质渗漏率增加。【结论】2.0mmol·kg-1以上铜处理引起苋菜活性氧代谢失衡，明显降低净光合速率和实际量子效率，加剧过氧化作用，导致植株生长严重受阻。关键词：苋菜；铜毒；光合作用；活性氧代谢EffectsofDifferentCopperLevelsonPhotosynthetic

3、ParametersandActiveOxygenMetabolismofAmaranthustricolorSeedlingsKEShi-sheng(SchoolofLifeSciences,TaizhouUniversity,Linhai317000,Zhejiang)Abstract:【Objective】Theobjectiveofthisstudywastogainbetterinsightintothephysiologicalmechanismsofcopper(Cu)onphotosynthesisandactiveoxygenmetabolisminthree-colo

4、uredamaranthplant(Amaranthustricolor).【Method】Three-colouredamaranthseedlingsweresubjectedtodifferentCulevelsinsoilsduringthewholeexperimentalperiod.Theparametersofgrowth,photosynthesis,mineralelementscontentsandactiveoxygenmetabolismwereinvestigatedbyusingplantphysiologicalmethods.【Result】2.0-4.

5、0mmolCu·kg-1treatmentdecreasedthewholeplantdrymassto91%-73%.Netphotosyntheticrate(Pn)andstomalalconductance(Gs)inthethirdleavesofthree-colouredamaranthseedlingstreatedwith2.0-4.0mmolCu·kg-1weresimilarlyreduced.NoneoftheinvestigatedCulevelsdecreasedinternalCO2concentration(Ci).TheeffectofCuonpoten

6、tialefficiencyofphotosystemⅡ(Fv/Fm)wasnegligible,whiletheeffectofCuonPSⅡquantumefficiency(ΦPSⅡ)afterplantadaptationinactinicirradiationwasmorenoticeable.ThiscouldimplythatthereduceddemandofdarkphaseofphotosynthesisforATPandNADPHinleavescausedadown-regulationofPSⅡphotochemistry.Ontheotherhand,decr

7、easeinwaterpercentage,contentsofphotosyntheticpigmentsandmineralelementsincludingFe,KandMg,significantincreaseinCucontentwereobservedinthirdleavesofCu-treatedplants.Superoxidedismutase(SOD)andguaiacolperoxidase(POD)act