简介：Threetreatmentsconsistingof0%,15%,and30%seawaterwereinvestigatedtoanalysetheecotypicvariabilitiesamongfivepopulationsofJerusalemartichoke(Helianthustuberosus)regardingtheirresponsestoseawaterstressunderahydroponicculturesystem.Analysesweredone2,4,and6daysaftertreatments.The15%and30%seawatertreatmentsreducedthegrowthratesofrootsandshootsofH.tuberosuspopulations.Theactivitiesofsuperoxidedismutase,peroxidase,andcatalasemajoredintheleaveswerestimulatedundertheseawaterstress.Theelectrolyteleakageandmalondialdehydecontentsoftheleaveswerealsostimulatedowingtoseawaterstress.Thecontentsofprolineandsoluble-sugarsintheleavesincreasedsignificantlywithincreasingseawaterconcentrations.TheconcentrationsofNa+,K+,andCl-intheaerialpartsandrootsincreasedwithanincreaseintheseawaterconcentrationthroughouttheexperimentalperiod.TherewereecotypicdifferencesamongthefivepopulationsofH.tuberosusasevidencedbytheanalysesoftheaboveitemsinbothaerialpartsandrootsunderseawatertreatment.Themagnitudeoftheecotypicvariancecomponentsindicatedthatasubstantialproportionofthetotalvariationforthesephysiologicalandbiochemicalresponseswereowingtoecotype,indicatingthepossibilityofimprovementthroughhybridizationandselection.

简介：Cadmium(Cd)ishighlytoxictoplants,animals,andhumans.Limitedinformationisavailableontheroleofnitricoxide(NO)and/or24-epibrassinolide(EBR)inresponseofplantstoCdstress.Inthisstudy,ahydroponicexperimentwasperformedtoinvestigatetheeffectsofNOand/orEBRonpeanutplantssubjectedtoCdstress(200μmolL-1)withsodiumnitroprusside(SNP,anexogenousNOdonor)(250μmolL-1)and/orEBR(0.1μmolL-1)addition.TheresultsshowedthatCdexposureinhibitedplantgrowth,andthisstresswasalleviatedbyexogenousNOorEBR,andespeciallythecombinationofthetwo.TreatmentwithCdinhibitedthegrowthofpeanutseedlings,decreasedchlorophyllcontent,andsignificantlyincreasedtheCdconcentrationinplants.Furthermore,theconcentrationofreactiveoxygenspecies(ROS)markedlyincreasedinpeanutseedlingsunderCdstress,resultingintheaccumulationofmalondialdehyde(MDA)andprolineinleavesandroots.UnderCdstress,applicationsofSNP,EBR,andespeciallythetwoincombinationsignificantlyreducedthetranslocationofCdfromrootstoleaves,increasedthechlorophyllcontent,decreasedtheconcentrationsofROS,MDA,andproline,andsignificantlyenhancedtheactivitiesofsuperoxidedismutase(SOD),peroxidase(POD),andcatalase(CAT)inpeanutseedlings.ExogenousNOand/orEBRalsostimulatedtheactivitiesofnitratereductase(NR)andnitricoxidesynthase(NOS)andincreasedthecontentsofantioxidants,suchasascorbicacid(AsA)andreducedglutathione(GSH).Furthermore,exogenousNOand/orEBRenhancedCdaccumulationinthecellwallandthusdecreasedCddistributionintheorganellesintheroots.Theconcentrationsofcalcium(Ca),iron(Fe),magnesium(Mg),andzinc(Zn)werealsoregulatedbyexogenousNOorEBR,andespeciallybythetwoincombination.TheseresultsindicatedthatSNPandEBR,aloneandparticularlyincombination,canmitigatethenegativeeffectsofCdstressinpeanutplants.