IZVLEČEKBolezen zvijanja listov vinske trte je ena najpomembnejših in najbolj razširjenih virusnih bolezni vinske trte. Povzročitelji te bolezni so z zvijanjem listov vinske trte povezani virusi (Grapevine leafroll associated viruses, GLRaVs). S poskusom v rastlinjaku smo od junija do septembra, v rastni sezoni 2014, spremljali in primerjali fiziološke procese na trtah okuženih z enim (GLRaV-1), oziroma z dvema (GLRaV-1 in GLRaV-3) virusoma iz prej omenjenega kompleksa virusov. V sredini rastne sezone (meseca julija) se je negativni učinek na spremljane fiziološke procese v listih trte močneje izrazil pri mešani okužbi. Neto-fotosinteza (Pn) listov, okuženih z GLRaV-1 in GLRaV-3, je bila v primerjavi s Pn listov okuženih le z GLRaV-1 enkrat manjša. Podobno zmanjšanje smo opazili tudi pri prevodnosti listnih rež in transpiraciji ter v parametrih, povezanih s fotokemično učinkovitostjo fotosintetskega aparata (hitrost transporta elektronov po tilakoidi).Ključne besede: Vitis vinifera L.; bolezen zvijanja listov vinske trte; GLRaV; fotosinteza ABSTRACT PHYSIOLOGICAL RESPONSE OF GRAPEVINE Vitis vinifera L. TO GRAPEVINE LEAFROLL ASSOCIATED VIRUSES (GLRaV-1 and GLRaV-1 + GLRaV-3)Grapevine leafroll disease is one of the most severe viral diseases of grapevine caused by Grapevine leafroll-associated viruses (GLRaVs). Physiological processes were monitored on grapevines with single (GLRaV-1) and mixed (GLRaV-1 and GLRaV -3) viral infection under greenhouse conditions from June to September, in vegetation period 2014. In the mid of the season (July) negative effects of the virus infections on physiological processes were more severe in mixed than in single infection. The net-photosynthesis (Pn) of the leaves infected with GLRaV-1 and GLRaV-3 reached only a half of the Pn in GLRaV-1 infected grapevines. Similar reduction was found for stomatal conductance, transpiration and parameters related to photochemical efficiency (electron transport rate).