Translocation of 14C in ‘Stuart’ Pecan in the Spring following Assimilation of 14CO2 during the Previous Growing Season1

Abstract

Abstract Leaves on selected branches of 3-year-old ‘Stuart’ pecan ( Carya illinoensis (Wang) K. Koch) trees were treated weekly with 14 CO 2 for one growing season. Carbon-14 distribution within the tree during dormancy and its mobilization the following season were followed by autoradiography and liquid scintillation counting. During dormancy, 14 C distribution was predominantly on the treated side of the tree. Tissues that developed during the season of treatment were heavily labelled. Carbon-14 mobilization was evident at bud break. Translocation was primarily to new growth, i.e., to leaves, shoots, pistillate and staminate inflorescences, and new roots. First-formed leaves, veins, and primary growth were more heavily labelled than later leaves, interveinal tissue, or secondary growth. Tissues from treated branches were labelled more intensely than those from untreated branches. Storage substrates decreased as shoots developed.