Oriented translocation of energy in grafted reef corals

Colonies of the Red Sea reef coral Stylophora pistillata were grafted with alien branches (alografts), which had been labelled by NaH¹⁴CO₃ in the light. The "cold" host-colonies translocated the ¹⁴C-containing photosynthetic metabolites in an oriented pathway from the grafted branches into their own tissues. The highest accumulations of ¹⁴C products were detected in specific branch-tips of the host, away from the contact zones. The "recipient" colonies utilize these energy-rich materials for their metabolic requirements. The ¹⁴CO₂ produced through respiration is consequently detected in the skeletal-carbonate of the tips as Ca¹⁴CO₃. The purple morph of S. pistillata is found to be superior to the yellow morph.