Defenceproteinsareakindofchemicaldefencecompounds.Theyplayakeyroleinplantrestrainingbioticandabioticharm.Toilluminateactivitiesofsomedefenseproteinsassociatedwithageorplantfamilyoflarch,thelarchneedleswerecollectedfromtwodifferentfamiliesofKoreanlarch,Larixolgensisandahybridlarch,L.kaempferi×L.gmelinii,respectively,andthentheactivitiesofdefenceproteinsinthoseweretestedusingaUVspectrophotometry.Theresultsshowedthattheactivitiesofprotectiveenzymesatthe16-/17-and19-year-agegroupswerehigherthanthoseattheotheragegroupsinthebothlarchspecies.Whiletheactivitiesofpolyphenoloxidase(PPO)atthe16-/17-year-agegroupandphenylalanineammonia-lyase(PAL)andproteaseinhibitorsatthe19-year-agegroupwerethehighestamongallagegroups.Then,comparedwithL.olgensis,thehybridlarchhadsignificanteffectsontheactivitiesofprotectiveenzymes.TheeffectsofplantfamilyontheactivitiesofPALandchymotrypsininhibitorweresignificantlydifferent,andthenthoseontheactivitiesofPPOwerenotsignificantlydifferent.TheeffectsofthetwofamiliesinL.olgensisontheactivitiesoftrypsininhibitor(TI)weresignificantlydifferent,whilethoseinthehybridlarchontheactivitiesofTIwerecontrary.Toconclusionsshowedthatthedifferentageandplantfamilysignificantlyaffectedtheactivitiesofdefenceproteinsintheneedlesoftwolarchspecies,andthenenhancedthelarchresistancetopests.Thesecouldplayakeyfunctioninforestrytreegeneticimprovementandmanagementinfuture.
