SalicorniaBigelovii

HORTSCIENCE49(9):1154–1157.2014.PotentialofProducingSalicorniabigeloviiHydroponicallyasaVegetableatModerateNaClSalinityYunKongandYoubinZheng1SchoolofEnvironmentalSciences,UniversityofGuelph,Guelph,ONN1G2W1,Canada;andVinelandResearchandInnovationCentre,Vineland,Ontario,CanadaAdditionalindexwords.biomassaccumulation,NaClconcentration,plantgrowth,sodiumuptake,waterconsumptionAbstract.Salicorniabigeloviiisahalophytethatiscapableofgrowingunderhighsalinity.ToevaluatethepotentialofproducingS.bigeloviihydroponicallyasavegetableatmoderateNaClconcentrations,plantsweregrowninnutrientsolutionswith6,8,and10mMNaCl,andwith200mMNaClasacontrol.Resultsshowedthatplantshadareducedmainstemlength,canopywidth,stemdiameter,androotsystemlengthin6to10mMNaClcomparedwiththosein200mM.Also,freshweightincrease,freshanddryweightsofindividualplants,marketableyield,andwateruseefficiencyoftheplantsgrowninsolutionswith6to10mMNaClweresignificantlylowerthanthosegrownin200mM.Associatedwiththereducedgrowthattributes,remarkabledecreasesinsodiumuptakebytheplantswerealsoobtainedin6to10vs.200mMNaCl.TheresultssuggestthatS.bigeloviiisnotagoodcandidateforhydroponicproductionasavegetableatmoderateNaClsalinityresultingfromreducedgrowthattributes,whicharepossiblyassociatedwithdecreasedsodiumuptake.Hydroponicvegetablegrowersaresearch-ingforwaysofreducingdischargeandin-creasingon-farmreuseofdrainage(ShannonandGrieve,2000),becausedischargewastesbothwaterandfertilizer,pollutestheenvi-ronment,andsometimesevenresultsinsoilsalinization(Varlagasetal.,2010).Oneofthemostimportantfactorslimitingthereuseofnutrientsolutionsforhydroponicproductionofcommonvegetables(e.g.,cucumber,to-mato,andpepper)iselevatedsalinity(VanOs,1998),resultingmainlyfromNa+andCl–accumulationsattributabletodifferentialionuptakebythesecrops(KronzuckerandBritto,2011;Savvasetal.,2005).Analternativestrategyistoreusethesesalinizedsolutionsforhydroponicproductionofanothereco-nomicallyvaluableandmoresalt-tolerantcrop(GrieveandSuarez,1997;KongandZheng,2014;Pardossietal.,1999).Itrequiresthatthisspecieshastheabilitytowithstandelevatedsalinitylevelswithoutgrowthin-hibitionandreducedproductivitywhilepro-vidingasaleableproduct(Adleretal.,2003;GrieveandSuarez,1997).Salicorniabigeloviihasbeenlistedasoneofthemostsalt-tolerantspeciesamong1560halophytesandhasbeenshowntomaintainnormalgrowthevenwhensoilNaClconcen-trationexceeds1.3M,twotimesgreaterthanfull-strengthseawatersalinity(500mMNaCl;Glennetal.,1999).Also,S.bigeloviihasbeenintroducedtoU.S.andEuropeanfreshproducemarketsasaspecialtyvegeta-blewhereitssucculentyoungshootsaresoldas‘Samphire’or‘Seaasparagus’andareinhighdemandingourmetkitchensnotonlyfortheirsaltytaste,butalsofortheirhighnutri-tionalvalue(Venturaetal.,2011;VenturaandSagi,2013).S.bigeloviihasbeenevaluatedandcultivatedcommerciallyasavegetableinMexico,theMiddleEast,andAfrica(JaradatandShahid,2012;VenturaandSagi,2013;Zeraietal.,2010).CanS.bigeloviibeusedforhydroponicproductionasavegetableinthesalinizeddischargedsolutionsmentionedbefore?Cur-rently,limitedinformationisavailabletoanswerthisquestion.Grattanetal.(2008)hasfoundthatS.bigeloviihasthepotentialtoreusehypersalinedrainagewaterandthatitisabletogrowwellatone-thirdstrengthtofull-strengthseawatersalinity.Inthepre-viouslymentionedstudy,theplantswereevaluatedunderrelativelyhighNaClcon-centrations,i.e.,150to500mM(Grattanetal.,2008).However,theNaClconcentra-tionofmostnutrientsolutionsdischargedfromhydroponicproductionofcommonvegetablesrangesfrom6to8mM,amoderateNaClsalinity(VanOs,1998).SomestudiesindicatethatS.bigeloviiinhabitsthebroadestrangeofsalinityandhasverylittlepheno-typicresponsetosalinitygradient(Dagar,2005;JaradatandShahid,2012).Also,theplantsofthisspecieshavenotshownsig-nificantdifferencesinthegrowthrateandbiomassaccumulationatasalinitybetween0.5and10ppt(9and180mMNaCl,respectively)until35ppt(630mMNaCl;Brownetal.,1999).Conversely,otherstudiessuggesttheoptimalNaClconcentrationforS.bigeloviigrowthrangesfrom170to200mM(AyalaandO’Leary,1995;Webb,1966)or100to400mM(Parksetal.,2002),andasuboptimalNaClconcentrationof5mMcancausedecreasedplantgrowthassociatedwithreducedsodiumuptake(AyalaandO’Leary,1995).Becausethereportedresultsdiffer,furtherresearchisneededtodeterminewhethertherewillbesignificantreductionsinplantgrowthandsodiumuptakeforS.bigeloviigrownhydroponicallyatmoder-ateNaClconcentrations(i.e.,6to10mM).TheoverallobjectiveofthisstudywastoevaluatethepotentialofproducingS.bi-geloviihydroponicallyasavegetableatmod-erateNaClconcentrations,thesalinitylevelofnutrientsolutiondischargedfromhydro-ponicproductionofcommonvegetables.MaterialsandMethodsPlantmaterialsandgrowingconditions.ThestudywasconductedinagreenhouseintheEdmundC.BoveybuildingattheUni-versityofGuelph,Guelph,Ontario,Canada(lat.4333´N,long.8015´W).SeedsofS.bigelovii(SerraMarisCompany,Ninove,Belgium)weresowninamediumwithapeat-perliteratioof1:1byvolumeon21June2013.Onemonthaftersowing,seed-lingswithaheightof3cmweretrans-plantedintorockwoolcubes(1.5$StarterPlugs;GrodanInc.,Ontario,Canada),whichweree