1. Department of Forest Genetics and Plant Physiology, Umeå Plant Science Center, Swedish University of Agricultural Sciences, S901-83 Umeå, Sweden (J.L., D.Ö., M.K., S.K., M.B.-P., B.S., T.M., E.J.M.); and Department of Plant Physiology, Umeå Plant Science Center, Umeå University, S901-87 Umeå, Sweden (L.A.K.)