Catalysis of the reaction: UDP-apiose + 7-O-beta-D-glucosyl-5,7,4'-trihydroxyflavone = UDP + 7-O-(beta-D-apiofuranosyl-1,2-beta-D-glucosyl)-5,7,4'-trihydroxyflavone.
UDP-apiose:7-O-(beta-D-glucosyl)-flavone apiosyltransferase activity