Transfer of photosynthate and naturally occurring insecticidal compounds from host plants to the root hemiparasite Santalum acuminatum (Santalaceae)

Plant hemiparasites obtain a wide range of primary compounds from their hos t plants, including carbon, water and ions. In this paper, we examine the t ransfer of carbon from the host plant Myoporum parvifolium and the movement of an insecticidal compound from the host Melia azedarach to the root hemi parasite Santalum acuminatum (R. Br) (quandong). By using C-14 we determine d that glucose was moving from the M. parvifolium host to the parasite whil e the carbon fixed by quandongs was found to be mostly in mannitol. Mannito l occurred in fruit, leaf, stem and root tissue and also in xylem sap. We a lso provide evidence from direct infusion electrospray mass spectrometry (D IEMS) that quandong fruit from trees growing near Melia azedarach (L.) cont ain an insecticidal compound. This was supported by results from a bioassay in which apple moth (Epiphyas postvittana Walker) larvae suffered higher m ortality when fed only on quandong fruit that was growing near M. azedarach than those fed on quandong fruit from trees growing away from M. azedarach .