Natural 13C distribution in oil palm (Elaeis guineensis Jacq.) and consequences for allocation pattern

Oil palm has now become one of the most important crops, pahn oil representing nearly 25% of global plant oil consumption. Many studies have thus addressed oil palm ecophysiology and photosynthesis-based models of carbon allocation have been used. However, there is a lack of experimental data on carbon fixation and redistribution within pahn trees, and important C-sinks have not been fully characterized yet. Here, we carried out extensive measurement of natural "C-abundance (delta C-13) in oil palm tissues, including fruits at different maturation stages. We Ind a C-13-enrichment in heterotrophic organs compared to mature leaves, with roots being the most C-13-enriched. The delta C-13 in fruits decreased during maturation, reflecting the accumulation in "C-depleted lipids. We further used observed delta C-13 values to compute plausible carbon fluxes using a steady-state model of C-13-distribution including metabolic isotope effects (1211131,). The results suggest that fruits represent a major respiratory loss (approximate to 39% of total tree respiration) and that sink organs such as fruits are fed by sucrose from leaves. That is, glucose appears to be a quantitatively important compound in palm tissues, but computations indicate that it is involved in dynamic starch metabolism rather that C-exchange between organs.