Leaf Veins Loop Around Defects

Tree branches transport nutrients through a series of essentially straight lines, whereas leaves carry nourishment through a network of loops. A research team lead by Eleni Katifori of The Rockefeller University used mathematical models to compare branch patterns and looped patterns for flexibility and economy in water and nutrient transport.

Computer simulations showed that loops allow leaf networks to be more adaptable. Random damage such as weather and insect trauma can be circumvented by a looped network. Looped systems can also adjust their flow rate more easily, which is useful in temperature extremes. Straight lines may be more efficient but loops were proven more resilient.

The fluorescent dye in the image below is flowing to the leaf tip.  The photograph shows how easily the dye is carried past an injury to the main leaf vein.

resilient leaf looping network

Image credit:  E.Katifori/Rockefeller University

Gray arrow  Videos: Watch Dye Proceed through Leaf Networks
Gray arrow  "Why Leaves Aren't Trees," Physical Review Focus

Gray arrow  "Damage and Fluctuations Induce Loops in Optimal Transport Networks," Phys. Rev. Lett. 104, 048704 (2010)

This research was performed by Eleni Katifori, Center for Studies in Physics and Biology, The Rockefeller University, New York; Gergely J. Szollosi, Biological Physics Department, Eotvos University, Budapest, Hungary; and Marcelo O. Magnasco, Laboratory of Mathematical Physics, The Rockefeller University, New York.  Research results were published in Physical Review Letters in January 2010 and presented at the APS March Meeting 2010.
Gray arrow  March Meeting Image Gallery

Gray arrow  All APS Physics Images