Nitrogen status and light environment influence dry matter partitioning incauliflower

Concepts of above-ground dry matter partitioning in cauliflower [Brassica o leracea L. (Botrytis Group)] as dependent on nitrogen (N) supply and light environment are presented. Leaf and stem partitioning depends on a function al relationship between stem dry weight and leaf area, independent of N sta tus. Dry matter partitioning into the inflorescence is sink-limited (potent ial capacity) at the beginning, and source limited (daily available assimil ates) later. The intrinsic specific growth rate of the inflorescence is dep endent on leaf N content. The model is parameterized and evaluated with dat a from field experiments. Applied to an independent data set, the model pre dictions of proportions of inflorescence, leaf, and stem on total dry matte r corresponded with measurements (r = 0.84,0.92 and 0.22, respectively) for different N fertilization rates and light treatments.