Variations of δ13C and δ15N in oil palm tree organs: An insight into C and N distribution

Abstract

Many studies have shown that seasonal variation in fruit bunch production occurs in relation to climatic factors and internal trophic conditions. As the annual fruit bunch production is important for planters, there is a need to get some insights into the carbon (C) and nitrogen (N) distribution in oil palm tree which are key factors in delineating plant C fluxes and nutrient cycling dynamics. Hence, this study utilises stable C and N isotope analyses to assess possible variations in the δ13C and δ15N signature in oil palm organs. Our study found that the average δ13C of each oil palm tree organs are; root:-27.1‰, frond:-27.9‰, leaflets:-29.1‰, mesocarp:-28.6‰ and kernel:-28.7‰. The δ13C results showed an enrichment of 13C in heterotrophic organs compared to leaflets. Whilst the average δ15N values of oil palm tree organs are; root: 4.4‰, frond: 8.9‰, leaflets: 1.6‰, mesocarp: 10.3‰ and kernel: 6.8‰. The δ15N results also showed 15N enrichment in heterotrophic organs compared to leaflets. In conclusion, there were clear isotopic differences between autotrophic leaflets and heterotrophic organs. This study demonstrates the applicability of stable isotope analysis (SIA) in providing novel insights into C and N distribution in oil palm tree whereby both factors are key in the understanding of oil palm physiology which in turn is crucial in maintaining a productive fruit bunch yield annually.