Analyses of citrus leaves and fruits, and radioisotope tracer work showed that the leaves could synthesize limonoids and that the trees could translocate limonoids from leaves to the fruit. These results suggest that limonoids in citrus fruit tissues are synthesized in leaves and translocated to the fruit. No evidence was found to support the presence of limonoid biosynthetic systems in the fruit tissues. © 1977.
Hasegawa, S., & Hoagland, J. E. (1977). Biosynthesis of limonoids in Citrus. Phytochemistry, 16(4), 469–471. https://doi.org/10.1016/S0031-9422(00)94330-9