Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 10, 2007
Publication Date: August 15, 2008
Citation: Bai, C., Wood, B.W., Reilly, C.C. 2008. Insights into the nutritional physiology of nickel. Acta Horticulturae. 772:365-368. Interpretive Summary: Little is known about the role of the nickel in plants, especially regarding its role in nitrogen usage by growing plants. This work found that nickel deficient trees exhibit a disruption of normal metabolism of various organic forms of nitrogen needed for normal growth and developmental processes. It is apparent that nitrogen management in agricultural systems is influenced by plant nickel nutritional status.
Technical Abstract: Nickel (Ni) is essential for plants, yet its physiological role is poorly understood. Ni-deficient and Ni-sufficient pecan [Carya illinoinensis (Wangenh.) K. Koch] trees were compared regarding the impact of Ni nutritional status on reduced nitrogen (N) forms present in xylem sap at spring bud break. High performance liquid chromatography (HPLC) of xylem sap of Ni-sufficient trees found organic reduced N-forms to be primarily ureides (73%; citrulline > xanthine > ureidoglycolate > allantoic acid ' allantoin ' uric acid ' urea), followed by amide-N (26%; asparagine), and amino-N (1%; tryptamine and '-phenylethylamine). Nickel deficiency reduced xylem sap concentration of xanthine, asparagine, and '-phenylethylamine, yet greatly increased citrulline and allantoic acid. These data indicate that pecan is likely a ureide-N transporter and that Ni deficiency potentially disrupts ureide catabolism and Urea Cycle functionality; thus potentially disrupting normal N-cycling during early spring when N reserves are being remobilized to sinks.